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384febcdc2
openssh/openssh-9.6p1-gssapi-keyex.patch
Zoltan Fridrich 384febcdc2 Gssapi-keyex: fix issues found by static analysis 
Related: RHEL-60564

Signed-off-by: Zoltan Fridrich <zfridric@redhat.com>
2024-10-14 16:05:48 +02:00

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diff --color -ruNp a/auth2.c b/auth2.c
--- a/auth2.c 2024-09-16 11:45:56.858133241 +0200
+++ b/auth2.c 2024-09-16 11:46:34.688939755 +0200
@@ -71,6 +71,7 @@ extern Authmethod method_passwd;
extern Authmethod method_kbdint;
extern Authmethod method_hostbased;
#ifdef GSSAPI
+extern Authmethod method_gsskeyex;
extern Authmethod method_gssapi;
#endif
@@ -78,6 +79,7 @@ Authmethod *authmethods[] = {
&method_none,
&method_pubkey,
#ifdef GSSAPI
+ &method_gsskeyex,
&method_gssapi,
#endif
&method_passwd,
diff --color -ruNp a/auth2-gss.c b/auth2-gss.c
--- a/auth2-gss.c 2024-09-16 11:45:56.858133241 +0200
+++ b/auth2-gss.c 2024-09-16 11:46:34.689939776 +0200
@@ -51,6 +51,7 @@
#define SSH_GSSAPI_MAX_MECHS 2048
extern ServerOptions options;
+extern struct authmethod_cfg methodcfg_gsskeyex;
extern struct authmethod_cfg methodcfg_gssapi;
static int input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh);
@@ -59,6 +60,48 @@ static int input_gssapi_exchange_complet
static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
/*
+ * The 'gssapi_keyex' userauth mechanism.
+ */
+static int
+userauth_gsskeyex(struct ssh *ssh, const char *method)
+{
+ Authctxt *authctxt = ssh->authctxt;
+ int r, authenticated = 0;
+ struct sshbuf *b = NULL;
+ gss_buffer_desc mic, gssbuf;
+ u_char *p;
+ size_t len;
+
+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal_fr(r, "parsing");
+
+ if ((b = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ mic.value = p;
+ mic.length = len;
+
+ ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
+ "gssapi-keyex", ssh->kex->session_id);
+
+ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
+ fatal_f("sshbuf_mutable_ptr failed");
+ gssbuf.length = sshbuf_len(b);
+
+ /* gss_kex_context is NULL with privsep, so we can't check it here */
+ if (!GSS_ERROR(mm_ssh_gssapi_checkmic(gss_kex_context,
+ &gssbuf, &mic)))
+ authenticated = mm_ssh_gssapi_userok(authctxt->user,
+ authctxt->pw, 1);
+
+ sshbuf_free(b);
+ free(mic.value);
+
+ return (authenticated);
+}
+
+/*
* We only support those mechanisms that we know about (ie ones that we know
* how to check local user kuserok and the like)
*/
@@ -267,7 +310,7 @@ input_gssapi_exchange_complete(int type,
if ((r = sshpkt_get_end(ssh)) != 0)
fatal_fr(r, "parse packet");
- authenticated = mm_ssh_gssapi_userok(authctxt->user);
+ authenticated = mm_ssh_gssapi_userok(authctxt->user, authctxt->pw, 1);
authctxt->postponed = 0;
ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
@@ -315,7 +358,7 @@ input_gssapi_mic(int type, u_int32_t ple
gssbuf.length = sshbuf_len(b);
if (!GSS_ERROR(mm_ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic)))
- authenticated = mm_ssh_gssapi_userok(authctxt->user);
+ authenticated = mm_ssh_gssapi_userok(authctxt->user, authctxt->pw, 0);
else
logit("GSSAPI MIC check failed");
@@ -333,6 +376,11 @@ input_gssapi_mic(int type, u_int32_t ple
return 0;
}
+Authmethod method_gsskeyex = {
+ &methodcfg_gsskeyex,
+ userauth_gsskeyex,
+};
+
Authmethod method_gssapi = {
&methodcfg_gssapi,
userauth_gssapi,
diff --color -ruNp a/auth2-methods.c b/auth2-methods.c
--- a/auth2-methods.c 2024-07-01 06:36:28.000000000 +0200
+++ b/auth2-methods.c 2024-09-16 11:46:34.689939776 +0200
@@ -50,6 +50,11 @@ struct authmethod_cfg methodcfg_pubkey =
&options.pubkey_authentication
};
#ifdef GSSAPI
+struct authmethod_cfg methodcfg_gsskeyex = {
+ "gssapi-keyex",
+ NULL,
+ &options.gss_authentication
+};
struct authmethod_cfg methodcfg_gssapi = {
"gssapi-with-mic",
NULL,
@@ -76,6 +81,7 @@ static struct authmethod_cfg *authmethod
&methodcfg_none,
&methodcfg_pubkey,
#ifdef GSSAPI
+ &methodcfg_gsskeyex,
&methodcfg_gssapi,
#endif
&methodcfg_passwd,
diff --color -ruNp a/auth.c b/auth.c
--- a/auth.c 2024-07-01 06:36:28.000000000 +0200
+++ b/auth.c 2024-09-16 11:46:34.690939798 +0200
@@ -356,7 +356,8 @@ auth_root_allowed(struct ssh *ssh, const
case PERMIT_NO_PASSWD:
if (strcmp(method, "publickey") == 0 ||
strcmp(method, "hostbased") == 0 ||
- strcmp(method, "gssapi-with-mic") == 0)
+ strcmp(method, "gssapi-with-mic") == 0 ||
+ strcmp(method, "gssapi-keyex") == 0)
return 1;
break;
case PERMIT_FORCED_ONLY:
diff --color -ruNp a/canohost.c b/canohost.c
--- a/canohost.c 2024-07-01 06:36:28.000000000 +0200
+++ b/canohost.c 2024-09-16 11:46:34.690939798 +0200
@@ -35,6 +35,99 @@
#include "canohost.h"
#include "misc.h"
+/*
+ * Returns the remote DNS hostname as a string. The returned string must not
+ * be freed. NB. this will usually trigger a DNS query the first time it is
+ * called.
+ * This function does additional checks on the hostname to mitigate some
+ * attacks on legacy rhosts-style authentication.
+ * XXX is RhostsRSAAuthentication vulnerable to these?
+ * XXX Can we remove these checks? (or if not, remove RhostsRSAAuthentication?)
+ */
+
+char *
+remote_hostname(struct ssh *ssh)
+{
+ struct sockaddr_storage from;
+ socklen_t fromlen;
+ struct addrinfo hints, *ai, *aitop;
+ char name[NI_MAXHOST], ntop2[NI_MAXHOST];
+ const char *ntop = ssh_remote_ipaddr(ssh);
+
+ /* Get IP address of client. */
+ fromlen = sizeof(from);
+ memset(&from, 0, sizeof(from));
+ if (getpeername(ssh_packet_get_connection_in(ssh),
+ (struct sockaddr *)&from, &fromlen) == -1) {
+ debug("getpeername failed: %.100s", strerror(errno));
+ return xstrdup(ntop);
+ }
+
+ ipv64_normalise_mapped(&from, &fromlen);
+ if (from.ss_family == AF_INET6)
+ fromlen = sizeof(struct sockaddr_in6);
+
+ debug3("Trying to reverse map address %.100s.", ntop);
+ /* Map the IP address to a host name. */
+ if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name),
+ NULL, 0, NI_NAMEREQD) != 0) {
+ /* Host name not found. Use ip address. */
+ return xstrdup(ntop);
+ }
+
+ /*
+ * if reverse lookup result looks like a numeric hostname,
+ * someone is trying to trick us by PTR record like following:
+ * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_socktype = SOCK_DGRAM; /*dummy*/
+ hints.ai_flags = AI_NUMERICHOST;
+ if (getaddrinfo(name, NULL, &hints, &ai) == 0) {
+ logit("Nasty PTR record \"%s\" is set up for %s, ignoring",
+ name, ntop);
+ freeaddrinfo(ai);
+ return xstrdup(ntop);
+ }
+
+ /* Names are stored in lowercase. */
+ lowercase(name);
+
+ /*
+ * Map it back to an IP address and check that the given
+ * address actually is an address of this host. This is
+ * necessary because anyone with access to a name server can
+ * define arbitrary names for an IP address. Mapping from
+ * name to IP address can be trusted better (but can still be
+ * fooled if the intruder has access to the name server of
+ * the domain).
+ */
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = from.ss_family;
+ hints.ai_socktype = SOCK_STREAM;
+ if (getaddrinfo(name, NULL, &hints, &aitop) != 0) {
+ logit("reverse mapping checking getaddrinfo for %.700s "
+ "[%s] failed.", name, ntop);
+ return xstrdup(ntop);
+ }
+ /* Look for the address from the list of addresses. */
+ for (ai = aitop; ai; ai = ai->ai_next) {
+ if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2,
+ sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 &&
+ (strcmp(ntop, ntop2) == 0))
+ break;
+ }
+ freeaddrinfo(aitop);
+ /* If we reached the end of the list, the address was not there. */
+ if (ai == NULL) {
+ /* Address not found for the host name. */
+ logit("Address %.100s maps to %.600s, but this does not "
+ "map back to the address.", ntop, name);
+ return xstrdup(ntop);
+ }
+ return xstrdup(name);
+}
+
void
ipv64_normalise_mapped(struct sockaddr_storage *addr, socklen_t *len)
{
diff --color -ruNp a/canohost.h b/canohost.h
--- a/canohost.h 2024-07-01 06:36:28.000000000 +0200
+++ b/canohost.h 2024-09-16 11:46:34.690939798 +0200
@@ -15,6 +15,9 @@
#ifndef _CANOHOST_H
#define _CANOHOST_H
+struct ssh;
+
+char *remote_hostname(struct ssh *);
char *get_peer_ipaddr(int);
int get_peer_port(int);
char *get_local_ipaddr(int);
diff --color -ruNp a/clientloop.c b/clientloop.c
--- a/clientloop.c 2024-07-01 06:36:28.000000000 +0200
+++ b/clientloop.c 2024-09-16 11:46:34.690939798 +0200
@@ -115,6 +115,10 @@
#include "ssherr.h"
#include "hostfile.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
/* Permitted RSA signature algorithms for UpdateHostkeys proofs */
#define HOSTKEY_PROOF_RSA_ALGS "rsa-sha2-512,rsa-sha2-256"
@@ -1590,6 +1594,14 @@ client_loop(struct ssh *ssh, int have_pt
/* Do channel operations. */
channel_after_poll(ssh, pfd, npfd_active);
+#ifdef GSSAPI
+ if (options.gss_renewal_rekey &&
+ ssh_gssapi_credentials_updated(NULL)) {
+ debug("credentials updated - forcing rekey");
+ need_rekeying = 1;
+ }
+#endif
+
/* Buffer input from the connection. */
if (conn_in_ready)
client_process_net_input(ssh);
diff --color -ruNp a/configure.ac b/configure.ac
--- a/configure.ac 2024-09-16 11:45:56.870133497 +0200
+++ b/configure.ac 2024-09-16 11:46:34.691939819 +0200
@@ -774,6 +774,30 @@ int main(void) { if (NSVersionOfRunTimeL
[Use tunnel device compatibility to OpenBSD])
AC_DEFINE([SSH_TUN_PREPEND_AF], [1],
[Prepend the address family to IP tunnel traffic])
+ AC_MSG_CHECKING([if we have the Security Authorization Session API])
+ AC_TRY_COMPILE([#include <Security/AuthSession.h>],
+ [SessionCreate(0, 0);],
+ [ac_cv_use_security_session_api="yes"
+ AC_DEFINE([USE_SECURITY_SESSION_API], [1],
+ [platform has the Security Authorization Session API])
+ LIBS="$LIBS -framework Security"
+ AC_MSG_RESULT([yes])],
+ [ac_cv_use_security_session_api="no"
+ AC_MSG_RESULT([no])])
+ AC_MSG_CHECKING([if we have an in-memory credentials cache])
+ AC_TRY_COMPILE(
+ [#include <Kerberos/Kerberos.h>],
+ [cc_context_t c;
+ (void) cc_initialize (&c, 0, NULL, NULL);],
+ [AC_DEFINE([USE_CCAPI], [1],
+ [platform uses an in-memory credentials cache])
+ LIBS="$LIBS -framework Security"
+ AC_MSG_RESULT([yes])
+ if test "x$ac_cv_use_security_session_api" = "xno"; then
+ AC_MSG_ERROR([*** Need a security framework to use the credentials cache API ***])
+ fi],
+ [AC_MSG_RESULT([no])]
+ )
m4_pattern_allow([AU_IPv])
AC_CHECK_DECL([AU_IPv4], [],
AC_DEFINE([AU_IPv4], [0], [System only supports IPv4 audit records])
diff --color -ruNp a/gss-genr.c b/gss-genr.c
--- a/gss-genr.c 2024-07-01 06:36:28.000000000 +0200
+++ b/gss-genr.c 2024-09-16 11:46:34.708940181 +0200
@@ -42,9 +42,33 @@
#include "sshbuf.h"
#include "log.h"
#include "ssh2.h"
+#include "cipher.h"
+#include "sshkey.h"
+#include "kex.h"
+#include "digest.h"
+#include "packet.h"
#include "ssh-gss.h"
+typedef struct {
+ char *encoded;
+ gss_OID oid;
+} ssh_gss_kex_mapping;
+
+/*
+ * XXX - It would be nice to find a more elegant way of handling the
+ * XXX passing of the key exchange context to the userauth routines
+ */
+
+Gssctxt *gss_kex_context = NULL;
+
+static ssh_gss_kex_mapping *gss_enc2oid = NULL;
+
+int
+ssh_gssapi_oid_table_ok(void) {
+ return (gss_enc2oid != NULL);
+}
+
/* sshbuf_get for gss_buffer_desc */
int
ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
@@ -60,6 +84,159 @@ ssh_gssapi_get_buffer_desc(struct sshbuf
return 0;
}
+/* sshpkt_get of gss_buffer_desc */
+int
+ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *ssh, gss_buffer_desc *g)
+{
+ int r;
+ u_char *p;
+ size_t len;
+
+ if ((r = sshpkt_get_string(ssh, &p, &len)) != 0)
+ return r;
+ g->value = p;
+ g->length = len;
+ return 0;
+}
+
+/*
+ * Return a list of the gss-group1-sha1 mechanisms supported by this program
+ *
+ * We test mechanisms to ensure that we can use them, to avoid starting
+ * a key exchange with a bad mechanism
+ */
+
+char *
+ssh_gssapi_client_mechanisms(const char *host, const char *client,
+ const char *kex) {
+ gss_OID_set gss_supported = NULL;
+ OM_uint32 min_status;
+
+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &gss_supported)))
+ return NULL;
+
+ return ssh_gssapi_kex_mechs(gss_supported, ssh_gssapi_check_mechanism,
+ host, client, kex);
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+ const char *host, const char *client, const char *kex) {
+ struct sshbuf *buf = NULL;
+ size_t i;
+ int r = SSH_ERR_ALLOC_FAIL;
+ int oidpos, enclen;
+ char *mechs, *encoded;
+ u_char digest[SSH_DIGEST_MAX_LENGTH];
+ char deroid[2];
+ struct ssh_digest_ctx *md = NULL;
+ char *s, *cp, *p;
+
+ if (gss_enc2oid != NULL) {
+ for (i = 0; gss_enc2oid[i].encoded != NULL; i++)
+ free(gss_enc2oid[i].encoded);
+ free(gss_enc2oid);
+ }
+
+ gss_enc2oid = xmalloc(sizeof(ssh_gss_kex_mapping) *
+ (gss_supported->count + 1));
+
+ if ((buf = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ oidpos = 0;
+ s = cp = xstrdup(kex);
+ for (i = 0; i < gss_supported->count; i++) {
+ if (gss_supported->elements[i].length < 128 &&
+ (*check)(NULL, &(gss_supported->elements[i]), host, client)) {
+
+ deroid[0] = SSH_GSS_OIDTYPE;
+ deroid[1] = gss_supported->elements[i].length;
+
+ if ((md = ssh_digest_start(SSH_DIGEST_MD5)) == NULL ||
+ (r = ssh_digest_update(md, deroid, 2)) != 0 ||
+ (r = ssh_digest_update(md,
+ gss_supported->elements[i].elements,
+ gss_supported->elements[i].length)) != 0 ||
+ (r = ssh_digest_final(md, digest, sizeof(digest))) != 0)
+ fatal_fr(r, "digest failed");
+ ssh_digest_free(md);
+ md = NULL;
+
+ encoded = xmalloc(ssh_digest_bytes(SSH_DIGEST_MD5)
+ * 2);
+ enclen = __b64_ntop(digest,
+ ssh_digest_bytes(SSH_DIGEST_MD5), encoded,
+ ssh_digest_bytes(SSH_DIGEST_MD5) * 2);
+
+ cp = strncpy(s, kex, strlen(kex));
+ for ((p = strsep(&cp, ",")); p && *p != '\0';
+ (p = strsep(&cp, ","))) {
+ if (sshbuf_len(buf) != 0 &&
+ (r = sshbuf_put_u8(buf, ',')) != 0)
+ fatal_fr(r, "sshbuf_put_u8 error");
+ if ((r = sshbuf_put(buf, p, strlen(p))) != 0 ||
+ (r = sshbuf_put(buf, encoded, enclen)) != 0)
+ fatal_fr(r, "sshbuf_put error");
+ }
+
+ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
+ gss_enc2oid[oidpos].encoded = encoded;
+ oidpos++;
+ }
+ }
+ free(s);
+ gss_enc2oid[oidpos].oid = NULL;
+ gss_enc2oid[oidpos].encoded = NULL;
+
+ if ((mechs = sshbuf_dup_string(buf)) == NULL)
+ fatal_f("sshbuf_dup_string failed");
+
+ sshbuf_free(buf);
+
+ if (strlen(mechs) == 0) {
+ free(mechs);
+ mechs = NULL;
+ }
+
+ return (mechs);
+}
+
+gss_OID
+ssh_gssapi_id_kex(Gssctxt *ctx, char *name, int kex_type) {
+ int i = 0;
+
+#define SKIP_KEX_NAME(type) \
+ case type: \
+ if (strlen(name) < sizeof(type##_ID)) \
+ return GSS_C_NO_OID; \
+ name += sizeof(type##_ID) - 1; \
+ break;
+
+ switch (kex_type) {
+ SKIP_KEX_NAME(KEX_GSS_GRP1_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_GRP14_SHA256)
+ SKIP_KEX_NAME(KEX_GSS_GRP16_SHA512)
+ SKIP_KEX_NAME(KEX_GSS_GEX_SHA1)
+ SKIP_KEX_NAME(KEX_GSS_NISTP256_SHA256)
+ SKIP_KEX_NAME(KEX_GSS_C25519_SHA256)
+ default:
+ return GSS_C_NO_OID;
+ }
+
+#undef SKIP_KEX_NAME
+
+ while (gss_enc2oid[i].encoded != NULL &&
+ strcmp(name, gss_enc2oid[i].encoded) != 0)
+ i++;
+
+ if (gss_enc2oid[i].oid != NULL && ctx != NULL)
+ ssh_gssapi_set_oid(ctx, gss_enc2oid[i].oid);
+
+ return gss_enc2oid[i].oid;
+}
+
/* Check that the OID in a data stream matches that in the context */
int
ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
@@ -168,6 +345,7 @@ ssh_gssapi_build_ctx(Gssctxt **ctx)
(*ctx)->creds = GSS_C_NO_CREDENTIAL;
(*ctx)->client = GSS_C_NO_NAME;
(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
+ (*ctx)->first = 1;
}
/* Delete our context, providing it has been built correctly */
@@ -193,6 +371,12 @@ ssh_gssapi_delete_ctx(Gssctxt **ctx)
gss_release_name(&ms, &(*ctx)->client);
if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
gss_release_cred(&ms, &(*ctx)->client_creds);
+ sshbuf_free((*ctx)->shared_secret);
+ sshbuf_free((*ctx)->server_pubkey);
+ sshbuf_free((*ctx)->server_host_key_blob);
+ sshbuf_free((*ctx)->server_blob);
+ explicit_bzero((*ctx)->hash, sizeof((*ctx)->hash));
+ BN_clear_free((*ctx)->dh_client_pub);
free(*ctx);
*ctx = NULL;
@@ -216,7 +400,7 @@ ssh_gssapi_init_ctx(Gssctxt *ctx, int de
}
ctx->major = gss_init_sec_context(&ctx->minor,
- GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
+ ctx->client_creds, &ctx->context, ctx->name, ctx->oid,
GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
0, NULL, recv_tok, NULL, send_tok, flags, NULL);
@@ -246,8 +430,42 @@ ssh_gssapi_import_name(Gssctxt *ctx, con
}
OM_uint32
+ssh_gssapi_client_identity(Gssctxt *ctx, const char *name)
+{
+ gss_buffer_desc gssbuf;
+ gss_name_t gssname;
+ OM_uint32 status;
+ gss_OID_set oidset;
+
+ gssbuf.value = (void *) name;
+ gssbuf.length = strlen(gssbuf.value);
+
+ gss_create_empty_oid_set(&status, &oidset);
+ gss_add_oid_set_member(&status, ctx->oid, &oidset);
+
+ ctx->major = gss_import_name(&ctx->minor, &gssbuf,
+ GSS_C_NT_USER_NAME, &gssname);
+
+ if (!ctx->major)
+ ctx->major = gss_acquire_cred(&ctx->minor,
+ gssname, 0, oidset, GSS_C_INITIATE,
+ &ctx->client_creds, NULL, NULL);
+
+ gss_release_name(&status, &gssname);
+ gss_release_oid_set(&status, &oidset);
+
+ if (ctx->major)
+ ssh_gssapi_error(ctx);
+
+ return(ctx->major);
+}
+
+OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_t buffer, gss_buffer_t hash)
{
+ if (ctx == NULL)
+ return -1;
+
if ((ctx->major = gss_get_mic(&ctx->minor, ctx->context,
GSS_C_QOP_DEFAULT, buffer, hash)))
ssh_gssapi_error(ctx);
@@ -255,6 +473,19 @@ ssh_gssapi_sign(Gssctxt *ctx, gss_buffer
return (ctx->major);
}
+/* Priviledged when used by server */
+OM_uint32
+ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+{
+ if (ctx == NULL)
+ return -1;
+
+ ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
+ gssbuf, gssmic, NULL);
+
+ return (ctx->major);
+}
+
void
ssh_gssapi_buildmic(struct sshbuf *b, const char *user, const char *service,
const char *context, const struct sshbuf *session_id)
@@ -271,11 +502,16 @@ ssh_gssapi_buildmic(struct sshbuf *b, co
}
int
-ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host)
+ssh_gssapi_check_mechanism(Gssctxt **ctx, gss_OID oid, const char *host,
+ const char *client)
{
gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
OM_uint32 major, minor;
gss_OID_desc spnego_oid = {6, (void *)"\x2B\x06\x01\x05\x05\x02"};
+ Gssctxt *intctx = NULL;
+
+ if (ctx == NULL)
+ ctx = &intctx;
/* RFC 4462 says we MUST NOT do SPNEGO */
if (oid->length == spnego_oid.length &&
@@ -285,6 +521,10 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx
ssh_gssapi_build_ctx(ctx);
ssh_gssapi_set_oid(*ctx, oid);
major = ssh_gssapi_import_name(*ctx, host);
+
+ if (!GSS_ERROR(major) && client)
+ major = ssh_gssapi_client_identity(*ctx, client);
+
if (!GSS_ERROR(major)) {
major = ssh_gssapi_init_ctx(*ctx, 0, GSS_C_NO_BUFFER, &token,
NULL);
@@ -294,10 +534,66 @@ ssh_gssapi_check_mechanism(Gssctxt **ctx
GSS_C_NO_BUFFER);
}
- if (GSS_ERROR(major))
+ if (GSS_ERROR(major) || intctx != NULL)
ssh_gssapi_delete_ctx(ctx);
return (!GSS_ERROR(major));
}
+int
+ssh_gssapi_credentials_updated(Gssctxt *ctxt) {
+ static gss_name_t saved_name = GSS_C_NO_NAME;
+ static OM_uint32 saved_lifetime = 0;
+ static gss_OID saved_mech = GSS_C_NO_OID;
+ static gss_name_t name;
+ static OM_uint32 last_call = 0;
+ OM_uint32 lifetime, now, major, minor;
+ int equal;
+
+ now = time(NULL);
+
+ if (ctxt) {
+ debug("Rekey has happened - updating saved versions");
+
+ if (saved_name != GSS_C_NO_NAME)
+ gss_release_name(&minor, &saved_name);
+
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &saved_name, &saved_lifetime, NULL, NULL);
+
+ if (!GSS_ERROR(major)) {
+ saved_mech = ctxt->oid;
+ saved_lifetime+= now;
+ } else {
+ /* Handle the error */
+ }
+ return 0;
+ }
+
+ if (now - last_call < 10)
+ return 0;
+
+ last_call = now;
+
+ if (saved_mech == GSS_C_NO_OID)
+ return 0;
+
+ major = gss_inquire_cred(&minor, GSS_C_NO_CREDENTIAL,
+ &name, &lifetime, NULL, NULL);
+ if (major == GSS_S_CREDENTIALS_EXPIRED)
+ return 0;
+ else if (GSS_ERROR(major))
+ return 0;
+
+ major = gss_compare_name(&minor, saved_name, name, &equal);
+ gss_release_name(&minor, &name);
+ if (GSS_ERROR(major))
+ return 0;
+
+ if (equal && (saved_lifetime < lifetime + now - 10))
+ return 1;
+
+ return 0;
+}
+
#endif /* GSSAPI */
diff --color -ruNp a/gss-serv.c b/gss-serv.c
--- a/gss-serv.c 2024-07-01 06:36:28.000000000 +0200
+++ b/gss-serv.c 2024-09-16 11:46:34.692939840 +0200
@@ -1,7 +1,7 @@
/* $OpenBSD: gss-serv.c,v 1.32 2020/03/13 03:17:07 djm Exp $ */
/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -44,17 +44,19 @@
#include "session.h"
#include "misc.h"
#include "servconf.h"
+#include "uidswap.h"
#include "ssh-gss.h"
+#include "monitor_wrap.h"
extern ServerOptions options;
static ssh_gssapi_client gssapi_client =
- { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER,
- GSS_C_NO_CREDENTIAL, NULL, {NULL, NULL, NULL, NULL}};
+ { GSS_C_EMPTY_BUFFER, GSS_C_EMPTY_BUFFER, GSS_C_NO_CREDENTIAL,
+ GSS_C_NO_NAME, NULL, {NULL, NULL, NULL, NULL, NULL}, 0, 0};
ssh_gssapi_mech gssapi_null_mech =
- { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL};
+ { NULL, NULL, {0, NULL}, NULL, NULL, NULL, NULL, NULL};
#ifdef KRB5
extern ssh_gssapi_mech gssapi_kerberos_mech;
@@ -141,6 +143,29 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss
}
/* Unprivileged */
+char *
+ssh_gssapi_server_mechanisms(void) {
+ if (supported_oids == NULL)
+ ssh_gssapi_prepare_supported_oids();
+ return (ssh_gssapi_kex_mechs(supported_oids,
+ &ssh_gssapi_server_check_mech, NULL, NULL,
+ options.gss_kex_algorithms));
+}
+
+/* Unprivileged */
+int
+ssh_gssapi_server_check_mech(Gssctxt **dum, gss_OID oid, const char *data,
+ const char *dummy) {
+ Gssctxt *ctx = NULL;
+ int res;
+
+ res = !GSS_ERROR(mm_ssh_gssapi_server_ctx(&ctx, oid));
+ ssh_gssapi_delete_ctx(&ctx);
+
+ return (res);
+}
+
+/* Unprivileged */
void
ssh_gssapi_supported_oids(gss_OID_set *oidset)
{
@@ -150,7 +175,9 @@ ssh_gssapi_supported_oids(gss_OID_set *o
gss_OID_set supported;
gss_create_empty_oid_set(&min_status, oidset);
- gss_indicate_mechs(&min_status, &supported);
+
+ if (GSS_ERROR(gss_indicate_mechs(&min_status, &supported)))
+ return;
while (supported_mechs[i]->name != NULL) {
if (GSS_ERROR(gss_test_oid_set_member(&min_status,
@@ -276,8 +303,48 @@ OM_uint32
ssh_gssapi_getclient(Gssctxt *ctx, ssh_gssapi_client *client)
{
int i = 0;
+ int equal = 0;
+ gss_name_t new_name = GSS_C_NO_NAME;
+ gss_buffer_desc ename = GSS_C_EMPTY_BUFFER;
+
+ if (options.gss_store_rekey && client->used && ctx->client_creds) {
+ if (client->mech->oid.length != ctx->oid->length ||
+ (memcmp(client->mech->oid.elements,
+ ctx->oid->elements, ctx->oid->length) !=0)) {
+ debug("Rekeyed credentials have different mechanism");
+ return GSS_S_COMPLETE;
+ }
- gss_buffer_desc ename;
+ if ((ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
+ ctx->client_creds, ctx->oid, &new_name,
+ NULL, NULL, NULL))) {
+ ssh_gssapi_error(ctx);
+ return (ctx->major);
+ }
+
+ ctx->major = gss_compare_name(&ctx->minor, client->name,
+ new_name, &equal);
+
+ if (GSS_ERROR(ctx->major)) {
+ ssh_gssapi_error(ctx);
+ return (ctx->major);
+ }
+
+ if (!equal) {
+ debug("Rekeyed credentials have different name");
+ return GSS_S_COMPLETE;
+ }
+
+ debug("Marking rekeyed credentials for export");
+
+ gss_release_name(&ctx->minor, &client->name);
+ gss_release_cred(&ctx->minor, &client->creds);
+ client->name = new_name;
+ client->creds = ctx->client_creds;
+ ctx->client_creds = GSS_C_NO_CREDENTIAL;
+ client->updated = 1;
+ return GSS_S_COMPLETE;
+ }
client->mech = NULL;
@@ -292,6 +359,13 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_g
if (client->mech == NULL)
return GSS_S_FAILURE;
+ if (ctx->client_creds &&
+ (ctx->major = gss_inquire_cred_by_mech(&ctx->minor,
+ ctx->client_creds, ctx->oid, &client->name, NULL, NULL, NULL))) {
+ ssh_gssapi_error(ctx);
+ return (ctx->major);
+ }
+
if ((ctx->major = gss_display_name(&ctx->minor, ctx->client,
&client->displayname, NULL))) {
ssh_gssapi_error(ctx);
@@ -309,6 +383,8 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_g
return (ctx->major);
}
+ gss_release_buffer(&ctx->minor, &ename);
+
/* We can't copy this structure, so we just move the pointer to it */
client->creds = ctx->client_creds;
ctx->client_creds = GSS_C_NO_CREDENTIAL;
@@ -319,11 +395,20 @@ ssh_gssapi_getclient(Gssctxt *ctx, ssh_g
void
ssh_gssapi_cleanup_creds(void)
{
- if (gssapi_client.store.filename != NULL) {
- /* Unlink probably isn't sufficient */
- debug("removing gssapi cred file\"%s\"",
- gssapi_client.store.filename);
- unlink(gssapi_client.store.filename);
+ krb5_ccache ccache = NULL;
+ krb5_error_code problem;
+
+ if (gssapi_client.store.data != NULL) {
+ if ((problem = krb5_cc_resolve(gssapi_client.store.data, gssapi_client.store.envval, &ccache))) {
+ debug_f("krb5_cc_resolve(): %.100s",
+ krb5_get_err_text(gssapi_client.store.data, problem));
+ } else if ((problem = krb5_cc_destroy(gssapi_client.store.data, ccache))) {
+ debug_f("krb5_cc_destroy(): %.100s",
+ krb5_get_err_text(gssapi_client.store.data, problem));
+ } else {
+ krb5_free_context(gssapi_client.store.data);
+ gssapi_client.store.data = NULL;
+ }
}
}
@@ -356,19 +441,23 @@ ssh_gssapi_do_child(char ***envp, u_int
/* Privileged */
int
-ssh_gssapi_userok(char *user)
+ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
{
OM_uint32 lmin;
+ (void) kex; /* used in privilege separation */
+
if (gssapi_client.exportedname.length == 0 ||
gssapi_client.exportedname.value == NULL) {
debug("No suitable client data");
return 0;
}
if (gssapi_client.mech && gssapi_client.mech->userok)
- if ((*gssapi_client.mech->userok)(&gssapi_client, user))
+ if ((*gssapi_client.mech->userok)(&gssapi_client, user)) {
+ gssapi_client.used = 1;
+ gssapi_client.store.owner = pw;
return 1;
- else {
+ } else {
/* Destroy delegated credentials if userok fails */
gss_release_buffer(&lmin, &gssapi_client.displayname);
gss_release_buffer(&lmin, &gssapi_client.exportedname);
@@ -382,14 +471,85 @@ ssh_gssapi_userok(char *user)
return (0);
}
-/* Privileged */
-OM_uint32
-ssh_gssapi_checkmic(Gssctxt *ctx, gss_buffer_t gssbuf, gss_buffer_t gssmic)
+/* These bits are only used for rekeying. The unpriviledged child is running
+ * as the user, the monitor is root.
+ *
+ * In the child, we want to :
+ * *) Ask the monitor to store our credentials into the store we specify
+ * *) If it succeeds, maybe do a PAM update
+ */
+
+/* Stuff for PAM */
+
+#ifdef USE_PAM
+static int ssh_gssapi_simple_conv(int n, const struct pam_message **msg,
+ struct pam_response **resp, void *data)
{
- ctx->major = gss_verify_mic(&ctx->minor, ctx->context,
- gssbuf, gssmic, NULL);
+ return (PAM_CONV_ERR);
+}
+#endif
- return (ctx->major);
+void
+ssh_gssapi_rekey_creds(void) {
+ int ok;
+#ifdef USE_PAM
+ int ret;
+ pam_handle_t *pamh = NULL;
+ struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
+ char *envstr;
+#endif
+
+ if (gssapi_client.store.filename == NULL &&
+ gssapi_client.store.envval == NULL &&
+ gssapi_client.store.envvar == NULL)
+ return;
+
+ ok = mm_ssh_gssapi_update_creds(&gssapi_client.store);
+
+ if (!ok)
+ return;
+
+ debug("Rekeyed credentials stored successfully");
+
+ /* Actually managing to play with the ssh pam stack from here will
+ * be next to impossible. In any case, we may want different options
+ * for rekeying. So, use our own :)
+ */
+#ifdef USE_PAM
+ ret = pam_start("sshd-rekey", gssapi_client.store.owner->pw_name,
+ &pamconv, &pamh);
+ if (ret)
+ return;
+
+ xasprintf(&envstr, "%s=%s", gssapi_client.store.envvar,
+ gssapi_client.store.envval);
+
+ ret = pam_putenv(pamh, envstr);
+ if (!ret)
+ pam_setcred(pamh, PAM_REINITIALIZE_CRED);
+ pam_end(pamh, PAM_SUCCESS);
+#endif
+}
+
+int
+ssh_gssapi_update_creds(ssh_gssapi_ccache *store) {
+ int ok = 0;
+
+ /* Check we've got credentials to store */
+ if (!gssapi_client.updated)
+ return 0;
+
+ gssapi_client.updated = 0;
+
+ temporarily_use_uid(gssapi_client.store.owner);
+ if (gssapi_client.mech && gssapi_client.mech->updatecreds)
+ ok = (*gssapi_client.mech->updatecreds)(store, &gssapi_client);
+ else
+ debug("No update function for this mechanism");
+
+ restore_uid();
+
+ return ok;
}
/* Privileged */
diff --color -ruNp a/gss-serv-krb5.c b/gss-serv-krb5.c
--- a/gss-serv-krb5.c 2024-07-01 06:36:28.000000000 +0200
+++ b/gss-serv-krb5.c 2024-09-16 11:46:34.692939840 +0200
@@ -1,7 +1,7 @@
/* $OpenBSD: gss-serv-krb5.c,v 1.9 2018/07/09 21:37:55 markus Exp $ */
/*
- * Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
+ * Copyright (c) 2001-2007 Simon Wilkinson. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -120,7 +120,7 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_cl
krb5_error_code problem;
krb5_principal princ;
OM_uint32 maj_status, min_status;
- int len;
+ const char *new_ccname, *new_cctype;
const char *errmsg;
if (client->creds == NULL) {
@@ -180,11 +180,26 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_cl
return;
}
- client->store.filename = xstrdup(krb5_cc_get_name(krb_context, ccache));
+ new_cctype = krb5_cc_get_type(krb_context, ccache);
+ new_ccname = krb5_cc_get_name(krb_context, ccache);
+
client->store.envvar = "KRB5CCNAME";
- len = strlen(client->store.filename) + 6;
- client->store.envval = xmalloc(len);
- snprintf(client->store.envval, len, "FILE:%s", client->store.filename);
+#ifdef USE_CCAPI
+ xasprintf(&client->store.envval, "API:%s", new_ccname);
+ client->store.filename = NULL;
+#else
+ if (new_ccname[0] == ':')
+ new_ccname++;
+ xasprintf(&client->store.envval, "%s:%s", new_cctype, new_ccname);
+ if (strcmp(new_cctype, "DIR") == 0) {
+ char *p;
+ p = strrchr(client->store.envval, '/');
+ if (p)
+ *p = '\0';
+ }
+ if ((strcmp(new_cctype, "FILE") == 0) || (strcmp(new_cctype, "DIR") == 0))
+ client->store.filename = xstrdup(new_ccname);
+#endif
#ifdef USE_PAM
if (options.use_pam)
@@ -193,9 +208,76 @@ ssh_gssapi_krb5_storecreds(ssh_gssapi_cl
krb5_cc_close(krb_context, ccache);
+ client->store.data = krb_context;
+
return;
}
+int
+ssh_gssapi_krb5_updatecreds(ssh_gssapi_ccache *store,
+ ssh_gssapi_client *client)
+{
+ krb5_ccache ccache = NULL;
+ krb5_principal principal = NULL;
+ char *name = NULL;
+ krb5_error_code problem;
+ OM_uint32 maj_status, min_status;
+
+ if ((problem = krb5_cc_resolve(krb_context, store->envval, &ccache))) {
+ logit("krb5_cc_resolve(): %.100s",
+ krb5_get_err_text(krb_context, problem));
+ return 0;
+ }
+
+ /* Find out who the principal in this cache is */
+ if ((problem = krb5_cc_get_principal(krb_context, ccache,
+ &principal))) {
+ logit("krb5_cc_get_principal(): %.100s",
+ krb5_get_err_text(krb_context, problem));
+ krb5_cc_close(krb_context, ccache);
+ return 0;
+ }
+
+ if ((problem = krb5_unparse_name(krb_context, principal, &name))) {
+ logit("krb5_unparse_name(): %.100s",
+ krb5_get_err_text(krb_context, problem));
+ krb5_free_principal(krb_context, principal);
+ krb5_cc_close(krb_context, ccache);
+ return 0;
+ }
+
+
+ if (strcmp(name,client->exportedname.value)!=0) {
+ debug("Name in local credentials cache differs. Not storing");
+ krb5_free_principal(krb_context, principal);
+ krb5_cc_close(krb_context, ccache);
+ krb5_free_unparsed_name(krb_context, name);
+ return 0;
+ }
+ krb5_free_unparsed_name(krb_context, name);
+
+ /* Name matches, so lets get on with it! */
+
+ if ((problem = krb5_cc_initialize(krb_context, ccache, principal))) {
+ logit("krb5_cc_initialize(): %.100s",
+ krb5_get_err_text(krb_context, problem));
+ krb5_free_principal(krb_context, principal);
+ krb5_cc_close(krb_context, ccache);
+ return 0;
+ }
+
+ krb5_free_principal(krb_context, principal);
+
+ if ((maj_status = gss_krb5_copy_ccache(&min_status, client->creds,
+ ccache))) {
+ logit("gss_krb5_copy_ccache() failed. Sorry!");
+ krb5_cc_close(krb_context, ccache);
+ return 0;
+ }
+
+ return 1;
+}
+
ssh_gssapi_mech gssapi_kerberos_mech = {
"toWM5Slw5Ew8Mqkay+al2g==",
"Kerberos",
@@ -203,7 +285,8 @@ ssh_gssapi_mech gssapi_kerberos_mech = {
NULL,
&ssh_gssapi_krb5_userok,
NULL,
- &ssh_gssapi_krb5_storecreds
+ &ssh_gssapi_krb5_storecreds,
+ &ssh_gssapi_krb5_updatecreds
};
#endif /* KRB5 */
diff --color -ruNp a/kex.c b/kex.c
--- a/kex.c 2024-07-01 06:36:28.000000000 +0200
+++ b/kex.c 2024-09-16 11:46:34.692939840 +0200
@@ -297,17 +297,37 @@ static int
kex_compose_ext_info_server(struct ssh *ssh, struct sshbuf *m)
{
int r;
+ int have_key = 0;
+ int ext_count = 2;
+
+#ifdef GSSAPI
+ /*
+ * Currently GSS KEX don't provide host keys as optional message, so
+ * no reasons to announce the publickey-hostbound extension
+ */
+ if (ssh->kex->gss == NULL)
+ have_key = 1;
+#endif
+ ext_count += have_key;
+
if (ssh->kex->server_sig_algs == NULL &&
(ssh->kex->server_sig_algs = sshkey_alg_list(0, 1, 1, ',')) == NULL)
return SSH_ERR_ALLOC_FAIL;
- if ((r = sshbuf_put_u32(m, 3)) != 0 ||
+ if ((r = sshbuf_put_u32(m, ext_count)) != 0 ||
(r = sshbuf_put_cstring(m, "server-sig-algs")) != 0 ||
- (r = sshbuf_put_cstring(m, ssh->kex->server_sig_algs)) != 0 ||
- (r = sshbuf_put_cstring(m,
- "publickey-hostbound@openssh.com")) != 0 ||
- (r = sshbuf_put_cstring(m, "0")) != 0 ||
- (r = sshbuf_put_cstring(m, "ping@openssh.com")) != 0 ||
+ (r = sshbuf_put_cstring(m, ssh->kex->server_sig_algs)) != 0) {
+ error_fr(r, "compose");
+ return r;
+ }
+ if (have_key) {
+ if ((r = sshbuf_put_cstring(m, "publickey-hostbound@openssh.com")) != 0 ||
+ (r = sshbuf_put_cstring(m, "0")) != 0) {
+ error_fr(r, "compose");
+ return r;
+ }
+ }
+ if ((r = sshbuf_put_cstring(m, "ping@openssh.com")) != 0 ||
(r = sshbuf_put_cstring(m, "0")) != 0) {
error_fr(r, "compose");
return r;
@@ -737,6 +757,9 @@ kex_free(struct kex *kex)
sshbuf_free(kex->server_version);
sshbuf_free(kex->client_pub);
sshbuf_free(kex->session_id);
+#ifdef GSSAPI
+ free(kex->gss_host);
+#endif /* GSSAPI */
sshbuf_free(kex->initial_sig);
sshkey_free(kex->initial_hostkey);
free(kex->failed_choice);
diff --color -ruNp a/kexdh.c b/kexdh.c
--- a/kexdh.c 2024-07-01 06:36:28.000000000 +0200
+++ b/kexdh.c 2024-09-16 11:46:34.693939862 +0200
@@ -49,13 +49,23 @@ kex_dh_keygen(struct kex *kex)
{
switch (kex->kex_type) {
case KEX_DH_GRP1_SHA1:
+#ifdef GSSAPI
+ case KEX_GSS_GRP1_SHA1:
+#endif
kex->dh = dh_new_group1();
break;
case KEX_DH_GRP14_SHA1:
case KEX_DH_GRP14_SHA256:
+#ifdef GSSAPI
+ case KEX_GSS_GRP14_SHA1:
+ case KEX_GSS_GRP14_SHA256:
+#endif
kex->dh = dh_new_group14();
break;
case KEX_DH_GRP16_SHA512:
+#ifdef GSSAPI
+ case KEX_GSS_GRP16_SHA512:
+#endif
kex->dh = dh_new_group16();
break;
case KEX_DH_GRP18_SHA512:
diff --color -ruNp a/kexgen.c b/kexgen.c
--- a/kexgen.c 2024-07-01 06:36:28.000000000 +0200
+++ b/kexgen.c 2024-09-16 11:46:34.693939862 +0200
@@ -44,7 +44,7 @@
static int input_kex_gen_init(int, u_int32_t, struct ssh *);
static int input_kex_gen_reply(int type, u_int32_t seq, struct ssh *ssh);
-static int
+int
kex_gen_hash(
int hash_alg,
const struct sshbuf *client_version,
diff --color -ruNp a/kexgssc.c b/kexgssc.c
--- a/kexgssc.c 1970-01-01 01:00:00.000000000 +0100
+++ b/kexgssc.c 2024-10-14 15:18:02.491798105 +0200
@@ -0,0 +1,706 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+
+#include "includes.h"
+
+#include <openssl/crypto.h>
+#include <openssl/bn.h>
+
+#include <string.h>
+
+#include "xmalloc.h"
+#include "sshbuf.h"
+#include "ssh2.h"
+#include "sshkey.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+#include "packet.h"
+#include "dh.h"
+#include "digest.h"
+#include "ssherr.h"
+
+#include "ssh-gss.h"
+
+static int input_kexgss_hostkey(int, u_int32_t, struct ssh *);
+static int input_kexgss_continue(int, u_int32_t, struct ssh *);
+static int input_kexgss_complete(int, u_int32_t, struct ssh *);
+static int input_kexgss_error(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_group(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_continue(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_complete(int, u_int32_t, struct ssh *);
+
+static int
+kexgss_final(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ struct sshbuf *empty = NULL;
+ struct sshbuf *shared_secret = NULL;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ int r;
+
+ /*
+ * We _must_ have received a COMPLETE message in reply from the
+ * server, which will have set server_blob and msg_tok
+ */
+
+ /* compute shared secret */
+ switch (kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ case KEX_GSS_GRP14_SHA256:
+ case KEX_GSS_GRP16_SHA512:
+ r = kex_dh_dec(kex, gss->server_blob, &shared_secret);
+ break;
+ case KEX_GSS_C25519_SHA256:
+ if (sshbuf_ptr(gss->server_blob)[sshbuf_len(gss->server_blob)] & 0x80)
+ fatal("The received key has MSB of last octet set!");
+ r = kex_c25519_dec(kex, gss->server_blob, &shared_secret);
+ break;
+ case KEX_GSS_NISTP256_SHA256:
+ if (sshbuf_len(gss->server_blob) != 65)
+ fatal("The received NIST-P256 key did not match "
+ "expected length (expected 65, got %zu)",
+ sshbuf_len(gss->server_blob));
+
+ if (sshbuf_ptr(gss->server_blob)[0] != POINT_CONVERSION_UNCOMPRESSED)
+ fatal("The received NIST-P256 key does not have first octet 0x04");
+
+ r = kex_ecdh_dec(kex, gss->server_blob, &shared_secret);
+ break;
+ default:
+ r = SSH_ERR_INVALID_ARGUMENT;
+ break;
+ }
+ if (r != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ goto out;
+ }
+
+ if ((empty = sshbuf_new()) == NULL) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ hashlen = sizeof(hash);
+ r = kex_gen_hash(kex->hash_alg, kex->client_version,
+ kex->server_version, kex->my, kex->peer,
+ (gss->server_host_key_blob ? gss->server_host_key_blob : empty),
+ kex->client_pub, gss->server_blob, shared_secret,
+ hash, &hashlen);
+ sshbuf_free(empty);
+ if (r != 0)
+ fatal_f("Unexpected KEX type %d", kex->kex_type);
+
+ gss->buf.value = hash;
+ gss->buf.length = hashlen;
+
+ /* Verify that the hash matches the MIC we just got. */
+ if (GSS_ERROR(ssh_gssapi_checkmic(gss, &gss->buf, &gss->msg_tok)))
+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
+
+ gss_release_buffer(&gss->minor, &gss->msg_tok);
+
+ if (kex->gss_deleg_creds)
+ ssh_gssapi_credentials_updated(gss);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = gss;
+ else
+ ssh_gssapi_delete_ctx(&kex->gss);
+
+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+ r = kex_send_newkeys(ssh);
+
+ if (kex->gss != NULL) {
+ sshbuf_free(gss->server_host_key_blob);
+ gss->server_host_key_blob = NULL;
+ sshbuf_free(gss->server_blob);
+ gss->server_blob = NULL;
+ }
+out:
+ explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
+ explicit_bzero(hash, sizeof(hash));
+ sshbuf_free(shared_secret);
+ sshbuf_free(kex->client_pub);
+ kex->client_pub = NULL;
+ return r;
+}
+
+static int
+kexgss_init_ctx(struct ssh *ssh,
+ gss_buffer_desc *token_ptr)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags;
+ int r;
+
+ debug("Calling gss_init_sec_context");
+
+ gss->major = ssh_gssapi_init_ctx(gss, kex->gss_deleg_creds,
+ token_ptr, &send_tok, &ret_flags);
+
+ if (GSS_ERROR(gss->major)) {
+ /* XXX Useless code: Missing send? */
+ if (send_tok.length != 0) {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ fatal("gss_init_context failed");
+ }
+
+ /* If we've got an old receive buffer get rid of it */
+ if (token_ptr != GSS_C_NO_BUFFER)
+ gss_release_buffer(&gss->minor, token_ptr);
+
+ if (gss->major == GSS_S_COMPLETE) {
+ /* If mutual state flag is not true, kex fails */
+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
+ fatal("Mutual authentication failed");
+
+ /* If integ avail flag is not true kex fails */
+ if (!(ret_flags & GSS_C_INTEG_FLAG))
+ fatal("Integrity check failed");
+ }
+
+ /*
+ * If we have data to send, then the last message that we
+ * received cannot have been a 'complete'.
+ */
+ if (send_tok.length != 0) {
+ if (gss->first) {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
+ (r = sshpkt_put_stringb(ssh, kex->client_pub)) != 0)
+ fatal("failed to construct packet: %s", ssh_err(r));
+ gss->first = 0;
+ } else {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
+ fatal("failed to construct packet: %s", ssh_err(r));
+ }
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal("failed to send packet: %s", ssh_err(r));
+ gss_release_buffer(&gss->minor, &send_tok);
+
+ /* If we've sent them data, they should reply */
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, &input_kexgss_hostkey);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, &input_kexgss_continue);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, &input_kexgss_complete);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, &input_kexgss_error);
+ return 0;
+ }
+ /* No data, and not complete */
+ if (gss->major != GSS_S_COMPLETE)
+ fatal("Not complete, and no token output");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return kexgss_init_ctx(ssh, token_ptr);
+
+ return kexgss_final(ssh);
+}
+
+int
+kexgss_client(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ int r;
+
+ /* Initialise our GSSAPI world */
+ ssh_gssapi_build_ctx(&kex->gss);
+ if (ssh_gssapi_id_kex(kex->gss, kex->name, kex->kex_type) == GSS_C_NO_OID)
+ fatal("Couldn't identify host exchange");
+
+ if (ssh_gssapi_import_name(kex->gss, kex->gss_host))
+ fatal("Couldn't import hostname");
+
+ if (kex->gss_client &&
+ ssh_gssapi_client_identity(kex->gss, kex->gss_client))
+ fatal("Couldn't acquire client credentials");
+
+ /* Step 1 */
+ switch (kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ case KEX_GSS_GRP14_SHA256:
+ case KEX_GSS_GRP16_SHA512:
+ r = kex_dh_keypair(kex);
+ break;
+ case KEX_GSS_NISTP256_SHA256:
+ r = kex_ecdh_keypair(kex);
+ break;
+ case KEX_GSS_C25519_SHA256:
+ r = kex_c25519_keypair(kex);
+ break;
+ default:
+ fatal_f("Unexpected KEX type %d", kex->kex_type);
+ }
+ if (r != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ return r;
+ }
+ return kexgss_init_ctx(ssh, GSS_C_NO_BUFFER);
+}
+
+static int
+input_kexgss_hostkey(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ u_char *tmp = NULL;
+ size_t tmp_len = 0;
+ int r;
+
+ debug("Received KEXGSS_HOSTKEY");
+ if (gss->server_host_key_blob)
+ fatal("Server host key received more than once");
+ if ((r = sshpkt_get_string(ssh, &tmp, &tmp_len)) != 0)
+ fatal("Failed to read server host key: %s", ssh_err(r));
+ if ((gss->server_host_key_blob = sshbuf_from(tmp, tmp_len)) == NULL)
+ fatal("sshbuf_from failed");
+ return 0;
+}
+
+static int
+input_kexgss_continue(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, NULL);
+
+ debug("Received GSSAPI_CONTINUE");
+ if (gss->major == GSS_S_COMPLETE)
+ fatal("GSSAPI Continue received from server when complete");
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("Failed to read token: %s", ssh_err(r));
+ if (!(gss->major & GSS_S_CONTINUE_NEEDED))
+ fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
+ return kexgss_init_ctx(ssh, &recv_tok);
+}
+
+static int
+input_kexgss_complete(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ u_char c;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, NULL);
+
+ debug("Received GSSAPI_COMPLETE");
+ if (gss->msg_tok.value != NULL)
+ fatal("Received GSSAPI_COMPLETE twice?");
+ if ((r = sshpkt_getb_froms(ssh, &gss->server_blob)) != 0 ||
+ (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &gss->msg_tok)) != 0)
+ fatal("Failed to read message: %s", ssh_err(r));
+
+ /* Is there a token included? */
+ if ((r = sshpkt_get_u8(ssh, &c)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ if (c) {
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0)
+ fatal("Failed to read token: %s", ssh_err(r));
+ /* If we're already complete - protocol error */
+ if (gss->major == GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
+ } else {
+ if (gss->major != GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
+ }
+ if ((r = sshpkt_get_end(ssh)) != 0)
+ fatal("Expecting end of packet.");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return kexgss_init_ctx(ssh, &recv_tok);
+
+ gss_release_buffer(&gss->minor, &recv_tok);
+ return kexgss_final(ssh);
+}
+
+static int
+input_kexgss_error(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ u_char *msg;
+ int r;
+
+ debug("Received Error");
+ if ((r = sshpkt_get_u32(ssh, &gss->major)) != 0 ||
+ (r = sshpkt_get_u32(ssh, &gss->minor)) != 0 ||
+ (r = sshpkt_get_string(ssh, &msg, NULL)) != 0 ||
+ (r = sshpkt_get_string(ssh, NULL, NULL)) != 0 || /* lang tag */
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt_get failed: %s", ssh_err(r));
+ fatal("GSSAPI Error: \n%.400s", msg);
+ return 0;
+}
+
+/*******************************************************/
+/******************** KEXGSSGEX ************************/
+/*******************************************************/
+
+int
+kexgssgex_client(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ int r;
+
+ /* Initialise our GSSAPI world */
+ ssh_gssapi_build_ctx(&kex->gss);
+ if (ssh_gssapi_id_kex(kex->gss, kex->name, kex->kex_type) == GSS_C_NO_OID)
+ fatal("Couldn't identify host exchange");
+
+ if (ssh_gssapi_import_name(kex->gss, kex->gss_host))
+ fatal("Couldn't import hostname");
+
+ if (kex->gss_client &&
+ ssh_gssapi_client_identity(kex->gss, kex->gss_client))
+ fatal("Couldn't acquire client credentials");
+
+ debug("Doing group exchange");
+ kex->min = DH_GRP_MIN;
+ kex->max = DH_GRP_MAX;
+ kex->nbits = dh_estimate(kex->dh_need * 8);
+
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUPREQ)) != 0 ||
+ (r = sshpkt_put_u32(ssh, kex->min)) != 0 ||
+ (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
+ (r = sshpkt_put_u32(ssh, kex->max)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("Failed to construct a packet: %s", ssh_err(r));
+
+ debug("Wait SSH2_MSG_KEXGSS_GROUP");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_GROUP, &input_kexgssgex_group);
+ return 0;
+}
+
+static int
+kexgssgex_final(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ struct sshbuf *buf = NULL;
+ struct sshbuf *empty = NULL;
+ struct sshbuf *shared_secret = NULL;
+ BIGNUM *dh_server_pub = NULL;
+ const BIGNUM *pub_key, *dh_p, *dh_g;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ int r = SSH_ERR_INTERNAL_ERROR;
+
+ /*
+ * We _must_ have received a COMPLETE message in reply from the
+ * server, which will have set server_blob and msg_tok
+ */
+
+ /* 7. C verifies that the key Q_S is valid */
+ /* 8. C computes shared secret */
+ if ((buf = sshbuf_new()) == NULL ||
+ (r = sshbuf_put_stringb(buf, gss->server_blob)) != 0 ||
+ (r = sshbuf_get_bignum2(buf, &dh_server_pub)) != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ goto out;
+ }
+ sshbuf_free(buf);
+ buf = NULL;
+
+ if ((shared_secret = sshbuf_new()) == NULL) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ if ((r = kex_dh_compute_key(kex, dh_server_pub, shared_secret)) != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ goto out;
+ }
+
+ if ((empty = sshbuf_new()) == NULL) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ DH_get0_key(kex->dh, &pub_key, NULL);
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
+ hashlen = sizeof(hash);
+ r = kexgex_hash(kex->hash_alg, kex->client_version,
+ kex->server_version, kex->my, kex->peer,
+ (gss->server_host_key_blob ? gss->server_host_key_blob : empty),
+ kex->min, kex->nbits, kex->max, dh_p, dh_g, pub_key,
+ dh_server_pub, sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
+ hash, &hashlen);
+ sshbuf_free(empty);
+ if (r != 0)
+ fatal("Failed to calculate hash: %s", ssh_err(r));
+
+ gss->buf.value = hash;
+ gss->buf.length = hashlen;
+
+ /* Verify that the hash matches the MIC we just got. */
+ if (GSS_ERROR(ssh_gssapi_checkmic(gss, &gss->buf, &gss->msg_tok)))
+ sshpkt_disconnect(ssh, "Hash's MIC didn't verify");
+
+ gss_release_buffer(&gss->minor, &gss->msg_tok);
+
+ if (kex->gss_deleg_creds)
+ ssh_gssapi_credentials_updated(gss);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = gss;
+ else
+ ssh_gssapi_delete_ctx(&kex->gss);
+
+ /* Finally derive the keys and send them */
+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+ r = kex_send_newkeys(ssh);
+
+ if (kex->gss != NULL) {
+ sshbuf_free(gss->server_host_key_blob);
+ gss->server_host_key_blob = NULL;
+ sshbuf_free(gss->server_blob);
+ gss->server_blob = NULL;
+ }
+out:
+ explicit_bzero(hash, sizeof(hash));
+ DH_free(kex->dh);
+ kex->dh = NULL;
+ BN_clear_free(dh_server_pub);
+ sshbuf_free(shared_secret);
+ return r;
+}
+
+static int
+kexgssgex_init_ctx(struct ssh *ssh,
+ gss_buffer_desc *token_ptr)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ const BIGNUM *pub_key;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags;
+ int r;
+
+ /* Step 2 - call GSS_Init_sec_context() */
+ debug("Calling gss_init_sec_context");
+
+ gss->major = ssh_gssapi_init_ctx(gss, kex->gss_deleg_creds,
+ token_ptr, &send_tok, &ret_flags);
+
+ if (GSS_ERROR(gss->major)) {
+ /* XXX Useless code: Missing send? */
+ if (send_tok.length != 0) {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ fatal("gss_init_context failed");
+ }
+
+ /* If we've got an old receive buffer get rid of it */
+ if (token_ptr != GSS_C_NO_BUFFER)
+ gss_release_buffer(&gss->minor, token_ptr);
+
+ if (gss->major == GSS_S_COMPLETE) {
+ /* If mutual state flag is not true, kex fails */
+ if (!(ret_flags & GSS_C_MUTUAL_FLAG))
+ fatal("Mutual authentication failed");
+
+ /* If integ avail flag is not true kex fails */
+ if (!(ret_flags & GSS_C_INTEG_FLAG))
+ fatal("Integrity check failed");
+ }
+
+ /*
+ * If we have data to send, then the last message that we
+ * received cannot have been a 'complete'.
+ */
+ if (send_tok.length != 0) {
+ if (gss->first) {
+ DH_get0_key(kex->dh, &pub_key, NULL);
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_INIT)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, pub_key)) != 0)
+ fatal("failed to construct packet: %s", ssh_err(r));
+ gss->first = 0;
+ } else {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok.value, send_tok.length)) != 0)
+ fatal("failed to construct packet: %s", ssh_err(r));
+ }
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal("failed to send packet: %s", ssh_err(r));
+ gss_release_buffer(&gss->minor, &send_tok);
+
+ /* If we've sent them data, they should reply */
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, &input_kexgss_hostkey);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, &input_kexgssgex_continue);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, &input_kexgssgex_complete);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, &input_kexgss_error);
+ return 0;
+ }
+ /* No data, and not complete */
+ if (gss->major != GSS_S_COMPLETE)
+ fatal("Not complete, and no token output");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return kexgssgex_init_ctx(ssh, token_ptr);
+
+ return kexgssgex_final(ssh);
+}
+
+static int
+input_kexgssgex_group(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ BIGNUM *p = NULL;
+ BIGNUM *g = NULL;
+ int r;
+
+ debug("Received SSH2_MSG_KEXGSS_GROUP");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_GROUP, NULL);
+
+ if ((r = sshpkt_get_bignum2(ssh, &p)) != 0 ||
+ (r = sshpkt_get_bignum2(ssh, &g)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("shpkt_get_bignum2 failed: %s", ssh_err(r));
+
+ if (BN_num_bits(p) < kex->min || BN_num_bits(p) > kex->max)
+ fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
+ kex->min, BN_num_bits(p), kex->max);
+
+ if ((kex->dh = dh_new_group(g, p)) == NULL)
+ fatal("dn_new_group() failed");
+ p = g = NULL; /* belong to kex->dh now */
+
+ if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ DH_free(kex->dh);
+ kex->dh = NULL;
+ return r;
+ }
+
+ return kexgssgex_init_ctx(ssh, GSS_C_NO_BUFFER);
+}
+
+static int
+input_kexgssgex_continue(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, NULL);
+
+ debug("Received GSSAPI_CONTINUE");
+ if (gss->major == GSS_S_COMPLETE)
+ fatal("GSSAPI Continue received from server when complete");
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("Failed to read token: %s", ssh_err(r));
+ if (!(gss->major & GSS_S_CONTINUE_NEEDED))
+ fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
+ return kexgssgex_init_ctx(ssh, &recv_tok);
+}
+
+static int
+input_kexgssgex_complete(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok = GSS_C_EMPTY_BUFFER;
+ u_char c;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_HOSTKEY, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_COMPLETE, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_ERROR, NULL);
+
+ debug("Received GSSAPI_COMPLETE");
+ if (gss->msg_tok.value != NULL)
+ fatal("Received GSSAPI_COMPLETE twice?");
+ if ((r = sshpkt_getb_froms(ssh, &gss->server_blob)) != 0 ||
+ (r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &gss->msg_tok)) != 0)
+ fatal("Failed to read message: %s", ssh_err(r));
+
+ /* Is there a token included? */
+ if ((r = sshpkt_get_u8(ssh, &c)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ if (c) {
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0)
+ fatal("Failed to read token: %s", ssh_err(r));
+ /* If we're already complete - protocol error */
+ if (gss->major == GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: received token when complete");
+ } else {
+ if (gss->major != GSS_S_COMPLETE)
+ sshpkt_disconnect(ssh, "Protocol error: did not receive final token");
+ }
+ if ((r = sshpkt_get_end(ssh)) != 0)
+ fatal("Expecting end of packet.");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return kexgssgex_init_ctx(ssh, &recv_tok);
+
+ gss_release_buffer(&gss->minor, &recv_tok);
+ return kexgssgex_final(ssh);
+}
+
+#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
diff --color -ruNp a/kexgsss.c b/kexgsss.c
--- a/kexgsss.c 1970-01-01 01:00:00.000000000 +0100
+++ b/kexgsss.c 2024-10-14 15:18:02.491798105 +0200
@@ -0,0 +1,601 @@
+/*
+ * Copyright (c) 2001-2009 Simon Wilkinson. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+
+#include <string.h>
+
+#include <openssl/crypto.h>
+#include <openssl/bn.h>
+
+#include "xmalloc.h"
+#include "sshbuf.h"
+#include "ssh2.h"
+#include "sshkey.h"
+#include "cipher.h"
+#include "kex.h"
+#include "log.h"
+#include "packet.h"
+#include "dh.h"
+#include "ssh-gss.h"
+#include "monitor_wrap.h"
+#include "misc.h" /* servconf.h needs misc.h for struct ForwardOptions */
+#include "servconf.h"
+#include "ssh-gss.h"
+#include "digest.h"
+#include "ssherr.h"
+
+extern ServerOptions options;
+
+static int input_kexgss_init(int, u_int32_t, struct ssh *);
+static int input_kexgss_continue(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_groupreq(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_init(int, u_int32_t, struct ssh *);
+static int input_kexgssgex_continue(int, u_int32_t, struct ssh *);
+
+int
+kexgss_server(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ gss_OID oid;
+ char *mechs;
+
+ /* Initialise GSSAPI */
+
+ /* If we're rekeying, privsep means that some of the private structures
+ * in the GSSAPI code are no longer available. This kludges them back
+ * into life
+ */
+ if (!ssh_gssapi_oid_table_ok()) {
+ mechs = ssh_gssapi_server_mechanisms();
+ free(mechs);
+ }
+
+ debug2_f("Identifying %s", kex->name);
+ oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
+ if (oid == GSS_C_NO_OID)
+ fatal("Unknown gssapi mechanism");
+
+ debug2_f("Acquiring credentials");
+
+ if (GSS_ERROR(mm_ssh_gssapi_server_ctx(&kex->gss, oid)))
+ fatal("Unable to acquire credentials for the server");
+
+ ssh_gssapi_build_ctx(&kex->gss);
+ if (kex->gss == NULL)
+ fatal("Unable to allocate memory for gss context");
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, &input_kexgss_init);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, &input_kexgss_continue);
+ debug("Wait SSH2_MSG_KEXGSS_INIT");
+ return 0;
+}
+
+static inline void
+kexgss_accept_ctx(struct ssh *ssh,
+ gss_buffer_desc *recv_tok,
+ gss_buffer_desc *send_tok,
+ OM_uint32 *ret_flags)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ int r;
+
+ gss->major = mm_ssh_gssapi_accept_ctx(gss, recv_tok, send_tok, ret_flags);
+ gss_release_buffer(&gss->minor, recv_tok);
+
+ if (gss->major != GSS_S_COMPLETE && send_tok->length == 0)
+ fatal("Zero length token output when incomplete");
+
+ if (gss->buf.value == NULL)
+ fatal("No client public key");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED) {
+ debug("Sending GSSAPI_CONTINUE");
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ gss_release_buffer(&gss->minor, send_tok);
+ }
+}
+
+static inline int
+kexgss_final(struct ssh *ssh,
+ gss_buffer_desc *send_tok,
+ OM_uint32 *ret_flags)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ gss_buffer_desc msg_tok;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ struct sshbuf *shared_secret = NULL;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+
+ if (GSS_ERROR(gss->major)) {
+ if (send_tok->length > 0) {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ fatal("accept_ctx died");
+ }
+
+ if (!(*ret_flags & GSS_C_MUTUAL_FLAG))
+ fatal("Mutual Authentication flag wasn't set");
+
+ if (!(*ret_flags & GSS_C_INTEG_FLAG))
+ fatal("Integrity flag wasn't set");
+
+ if (GSS_ERROR(mm_ssh_gssapi_sign(gss, &gss->buf, &msg_tok)))
+ fatal("Couldn't get MIC");
+
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
+ (r = sshpkt_put_stringb(ssh, gss->server_pubkey)) != 0 ||
+ (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ if (send_tok->length != 0) {
+ if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ } else {
+ if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt_send failed: %s", ssh_err(r));
+
+ gss_release_buffer(&gss->minor, send_tok);
+ gss_release_buffer(&gss->minor, &msg_tok);
+
+ hashlen = gss->hashlen;
+ memcpy(hash, gss->hash, hashlen);
+ explicit_bzero(gss->hash, sizeof(gss->hash));
+ shared_secret = gss->shared_secret;
+ gss->shared_secret = NULL;
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = gss;
+ else
+ ssh_gssapi_delete_ctx(&kex->gss);
+
+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+ r = kex_send_newkeys(ssh);
+
+ /* If this was a rekey, then save out any delegated credentials we
+ * just exchanged. */
+ if (options.gss_store_rekey)
+ ssh_gssapi_rekey_creds();
+
+ if (kex->gss != NULL) {
+ sshbuf_free(gss->server_pubkey);
+ gss->server_pubkey = NULL;
+ }
+ explicit_bzero(hash, sizeof(hash));
+ sshbuf_free(shared_secret);
+ return r;
+}
+
+static int
+input_kexgss_init(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ struct sshbuf *empty;
+ struct sshbuf *client_pubkey = NULL;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
+ debug("SSH2_MSG_KEXGSS_INIT received");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, NULL);
+
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_getb_froms(ssh, &client_pubkey)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ switch (kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ case KEX_GSS_GRP14_SHA256:
+ case KEX_GSS_GRP16_SHA512:
+ r = kex_dh_enc(kex, client_pubkey, &gss->server_pubkey, &gss->shared_secret);
+ break;
+ case KEX_GSS_NISTP256_SHA256:
+ r = kex_ecdh_enc(kex, client_pubkey, &gss->server_pubkey, &gss->shared_secret);
+ break;
+ case KEX_GSS_C25519_SHA256:
+ r = kex_c25519_enc(kex, client_pubkey, &gss->server_pubkey, &gss->shared_secret);
+ break;
+ default:
+ fatal_f("Unexpected KEX type %d", kex->kex_type);
+ }
+ if (r != 0) {
+ sshbuf_free(client_pubkey);
+ gss_release_buffer(&gss->minor, &recv_tok);
+ ssh_gssapi_delete_ctx(&kex->gss);
+ return r;
+ }
+
+ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
+
+ if ((empty = sshbuf_new()) == NULL) {
+ sshbuf_free(client_pubkey);
+ gss_release_buffer(&gss->minor, &recv_tok);
+ ssh_gssapi_delete_ctx(&kex->gss);
+ return SSH_ERR_ALLOC_FAIL;
+ }
+
+ /* Calculate the hash early so we can free the
+ * client_pubkey, which has reference to the parent
+ * buffer state->incoming_packet
+ */
+ gss->hashlen = sizeof(gss->hash);
+ r = kex_gen_hash(kex->hash_alg, kex->client_version, kex->server_version,
+ kex->peer, kex->my, empty, client_pubkey, gss->server_pubkey,
+ gss->shared_secret, gss->hash, &gss->hashlen);
+ sshbuf_free(empty);
+ sshbuf_free(client_pubkey);
+ if (r != 0) {
+ gss_release_buffer(&gss->minor, &recv_tok);
+ ssh_gssapi_delete_ctx(&kex->gss);
+ return r;
+ }
+
+ gss->buf.value = gss->hash;
+ gss->buf.length = gss->hashlen;
+
+ kexgss_accept_ctx(ssh, &recv_tok, &send_tok, &ret_flags);
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return 0;
+
+ return kexgss_final(ssh, &send_tok, &ret_flags);
+}
+
+static int
+input_kexgss_continue(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ kexgss_accept_ctx(ssh, &recv_tok, &send_tok, &ret_flags);
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return 0;
+
+ return kexgss_final(ssh, &send_tok, &ret_flags);
+}
+
+/*******************************************************/
+/******************** KEXGSSGEX ************************/
+/*******************************************************/
+
+int
+kexgssgex_server(struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ gss_OID oid;
+ char *mechs;
+
+ /* Initialise GSSAPI */
+
+ /* If we're rekeying, privsep means that some of the private structures
+ * in the GSSAPI code are no longer available. This kludges them back
+ * into life
+ */
+ if (!ssh_gssapi_oid_table_ok()) {
+ mechs = ssh_gssapi_server_mechanisms();
+ free(mechs);
+ }
+
+ debug2_f("Identifying %s", kex->name);
+ oid = ssh_gssapi_id_kex(NULL, kex->name, kex->kex_type);
+ if (oid == GSS_C_NO_OID)
+ fatal("Unknown gssapi mechanism");
+
+ debug2_f("Acquiring credentials");
+
+ if (GSS_ERROR(mm_ssh_gssapi_server_ctx(&kex->gss, oid)))
+ fatal("Unable to acquire credentials for the server");
+
+ ssh_gssapi_build_ctx(&kex->gss);
+ if (kex->gss == NULL)
+ fatal("Unable to allocate memory for gss context");
+
+ debug("Doing group exchange");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_GROUPREQ, &input_kexgssgex_groupreq);
+ return 0;
+}
+
+static inline void
+kexgssgex_accept_ctx(struct ssh *ssh,
+ gss_buffer_desc *recv_tok,
+ gss_buffer_desc *send_tok,
+ OM_uint32 *ret_flags)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ int r;
+
+ gss->major = mm_ssh_gssapi_accept_ctx(gss, recv_tok, send_tok, ret_flags);
+ gss_release_buffer(&gss->minor, recv_tok);
+
+ if (gss->major != GSS_S_COMPLETE && send_tok->length == 0)
+ fatal("Zero length token output when incomplete");
+
+ if (gss->dh_client_pub == NULL)
+ fatal("No client public key");
+
+ if (gss->major & GSS_S_CONTINUE_NEEDED) {
+ debug("Sending GSSAPI_CONTINUE");
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ gss_release_buffer(&gss->minor, send_tok);
+ }
+}
+
+static inline int
+kexgssgex_final(struct ssh *ssh,
+ gss_buffer_desc *send_tok,
+ OM_uint32 *ret_flags)
+{
+ struct kex *kex = ssh->kex;
+ Gssctxt *gss = kex->gss;
+ gss_buffer_desc msg_tok;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ const BIGNUM *pub_key, *dh_p, *dh_g;
+ struct sshbuf *shared_secret = NULL;
+ struct sshbuf *empty = NULL;
+ int r;
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, NULL);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, NULL);
+
+ if (GSS_ERROR(gss->major)) {
+ if (send_tok->length > 0) {
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_CONTINUE)) != 0 ||
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ fatal("accept_ctx died");
+ }
+
+ if (!(*ret_flags & GSS_C_MUTUAL_FLAG))
+ fatal("Mutual Authentication flag wasn't set");
+
+ if (!(*ret_flags & GSS_C_INTEG_FLAG))
+ fatal("Integrity flag wasn't set");
+
+ /* calculate shared secret */
+ shared_secret = sshbuf_new();
+ if (shared_secret == NULL) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+ if ((r = kex_dh_compute_key(kex, gss->dh_client_pub, shared_secret)) != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ goto out;
+ }
+
+ if ((empty = sshbuf_new()) == NULL) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ r = SSH_ERR_ALLOC_FAIL;
+ goto out;
+ }
+
+ DH_get0_key(kex->dh, &pub_key, NULL);
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
+ hashlen = sizeof(hash);
+ r = kexgex_hash(kex->hash_alg, kex->client_version, kex->server_version,
+ kex->peer, kex->my, empty, kex->min, kex->nbits, kex->max, dh_p, dh_g,
+ gss->dh_client_pub, pub_key, sshbuf_ptr(shared_secret),
+ sshbuf_len(shared_secret), hash, &hashlen);
+ sshbuf_free(empty);
+ if (r != 0)
+ fatal("kexgex_hash failed: %s", ssh_err(r));
+
+ gss->buf.value = hash;
+ gss->buf.length = hashlen;
+
+ if (GSS_ERROR(mm_ssh_gssapi_sign(gss, &gss->buf, &msg_tok)))
+ fatal("Couldn't get MIC");
+
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_COMPLETE)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, pub_key)) != 0 ||
+ (r = sshpkt_put_string(ssh, msg_tok.value, msg_tok.length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ if (send_tok->length != 0) {
+ if ((r = sshpkt_put_u8(ssh, 1)) != 0 || /* true */
+ (r = sshpkt_put_string(ssh, send_tok->value, send_tok->length)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+ } else {
+ if ((r = sshpkt_put_u8(ssh, 0)) != 0) /* false */
+ fatal("sshpkt failed: %s", ssh_err(r));
+ }
+ if ((r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt_send failed: %s", ssh_err(r));
+
+ gss_release_buffer(&gss->minor, send_tok);
+ gss_release_buffer(&gss->minor, &msg_tok);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = gss;
+ else
+ ssh_gssapi_delete_ctx(&kex->gss);
+
+ /* Finally derive the keys and send them */
+ if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+ r = kex_send_newkeys(ssh);
+
+ /* If this was a rekey, then save out any delegated credentials we
+ * just exchanged. */
+ if (options.gss_store_rekey)
+ ssh_gssapi_rekey_creds();
+
+ if (kex->gss != NULL)
+ BN_clear_free(gss->dh_client_pub);
+
+out:
+ explicit_bzero(hash, sizeof(hash));
+ DH_free(kex->dh);
+ kex->dh = NULL;
+ sshbuf_free(shared_secret);
+ return r;
+}
+
+static int
+input_kexgssgex_groupreq(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ struct kex *kex = ssh->kex;
+ const BIGNUM *dh_p, *dh_g;
+ int min = -1, max = -1, nbits = -1;
+ int cmin = -1, cmax = -1; /* client proposal */
+ int r;
+
+ /* 5. S generates an ephemeral key pair (do the allocations early) */
+
+ debug("SSH2_MSG_KEXGSS_GROUPREQ received");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_GROUPREQ, NULL);
+
+ /* store client proposal to provide valid signature */
+ if ((r = sshpkt_get_u32(ssh, &cmin)) != 0 ||
+ (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
+ (r = sshpkt_get_u32(ssh, &cmax)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ kex->nbits = nbits;
+ kex->min = cmin;
+ kex->max = cmax;
+ min = MAX(DH_GRP_MIN, cmin);
+ max = MIN(DH_GRP_MAX, cmax);
+ nbits = MAXIMUM(DH_GRP_MIN, nbits);
+ nbits = MINIMUM(DH_GRP_MAX, nbits);
+
+ if (max < min || nbits < min || max < nbits)
+ fatal("GSS_GEX, bad parameters: %d !< %d !< %d", min, nbits, max);
+
+ kex->dh = mm_choose_dh(min, nbits, max);
+ if (kex->dh == NULL) {
+ sshpkt_disconnect(ssh, "Protocol error: no matching group found");
+ fatal("Protocol error: no matching group found");
+ }
+
+ DH_get0_pqg(kex->dh, &dh_p, NULL, &dh_g);
+ if ((r = sshpkt_start(ssh, SSH2_MSG_KEXGSS_GROUP)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, dh_p)) != 0 ||
+ (r = sshpkt_put_bignum2(ssh, dh_g)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ if ((r = ssh_packet_write_wait(ssh)) != 0)
+ fatal("ssh_packet_write_wait: %s", ssh_err(r));
+
+ /* Compute our exchange value in parallel with the client */
+ if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0) {
+ ssh_gssapi_delete_ctx(&kex->gss);
+ DH_free(kex->dh);
+ kex->dh = NULL;
+ return r;
+ }
+
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, &input_kexgssgex_init);
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_CONTINUE, &input_kexgssgex_continue);
+ debug("Wait SSH2_MSG_KEXGSS_INIT");
+ return 0;
+}
+
+static int
+input_kexgssgex_init(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
+ debug("SSH2_MSG_KEXGSS_INIT received");
+ ssh_dispatch_set(ssh, SSH2_MSG_KEXGSS_INIT, NULL);
+
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_get_bignum2(ssh, &gss->dh_client_pub)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
+
+ kexgssgex_accept_ctx(ssh, &recv_tok, &send_tok, &ret_flags);
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return 0;
+
+ return kexgssgex_final(ssh, &send_tok, &ret_flags);
+}
+
+static int
+input_kexgssgex_continue(int type,
+ u_int32_t seq,
+ struct ssh *ssh)
+{
+ Gssctxt *gss = ssh->kex->gss;
+ gss_buffer_desc recv_tok, send_tok = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ret_flags = 0;
+ int r;
+
+ if ((r = ssh_gssapi_sshpkt_get_buffer_desc(ssh, &recv_tok)) != 0 ||
+ (r = sshpkt_get_end(ssh)) != 0)
+ fatal("sshpkt failed: %s", ssh_err(r));
+
+ kexgssgex_accept_ctx(ssh, &recv_tok, &send_tok, &ret_flags);
+ if (gss->major & GSS_S_CONTINUE_NEEDED)
+ return 0;
+
+ return kexgssgex_final(ssh, &send_tok, &ret_flags);
+}
+
+#endif /* defined(GSSAPI) && defined(WITH_OPENSSL) */
diff --color -ruNp a/kex.h b/kex.h
--- a/kex.h 2024-07-01 06:36:28.000000000 +0200
+++ b/kex.h 2024-09-16 11:46:34.710940224 +0200
@@ -29,6 +29,10 @@
#include "mac.h"
#include "crypto_api.h"
+#ifdef GSSAPI
+# include "ssh-gss.h" /* Gssctxt */
+#endif
+
#ifdef WITH_OPENSSL
# include <openssl/bn.h>
# include <openssl/dh.h>
@@ -102,6 +106,15 @@ enum kex_exchange {
KEX_C25519_SHA256,
KEX_KEM_SNTRUP761X25519_SHA512,
KEX_KEM_MLKEM768X25519_SHA256,
+#ifdef GSSAPI
+ KEX_GSS_GRP1_SHA1,
+ KEX_GSS_GRP14_SHA1,
+ KEX_GSS_GRP14_SHA256,
+ KEX_GSS_GRP16_SHA512,
+ KEX_GSS_GEX_SHA1,
+ KEX_GSS_NISTP256_SHA256,
+ KEX_GSS_C25519_SHA256,
+#endif
KEX_MAX
};
@@ -164,6 +177,13 @@ struct kex {
u_int flags;
int hash_alg;
int ec_nid;
+#ifdef GSSAPI
+ Gssctxt *gss;
+ int gss_deleg_creds;
+ int gss_trust_dns;
+ char *gss_host;
+ char *gss_client;
+#endif
char *failed_choice;
int (*verify_host_key)(struct sshkey *, struct ssh *);
struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
@@ -189,8 +209,10 @@ int kex_hash_from_name(const char *);
int kex_nid_from_name(const char *);
int kex_names_valid(const char *);
char *kex_alg_list(char);
+char *kex_gss_alg_list(char);
char *kex_names_cat(const char *, const char *);
int kex_has_any_alg(const char *, const char *);
+int kex_gss_names_valid(const char *);
int kex_assemble_names(char **, const char *, const char *);
void kex_proposal_populate_entries(struct ssh *, char *prop[PROPOSAL_MAX],
const char *, const char *, const char *, const char *, const char *);
@@ -224,6 +246,12 @@ int kexgex_client(struct ssh *);
int kexgex_server(struct ssh *);
int kex_gen_client(struct ssh *);
int kex_gen_server(struct ssh *);
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+int kexgssgex_client(struct ssh *);
+int kexgssgex_server(struct ssh *);
+int kexgss_client(struct ssh *);
+int kexgss_server(struct ssh *);
+#endif
int kex_dh_keypair(struct kex *);
int kex_dh_enc(struct kex *, const struct sshbuf *, struct sshbuf **,
@@ -256,6 +284,12 @@ int kexgex_hash(int, const struct sshbu
const BIGNUM *, const u_char *, size_t,
u_char *, size_t *);
+int kex_gen_hash(int hash_alg, const struct sshbuf *client_version,
+ const struct sshbuf *server_version, const struct sshbuf *client_kexinit,
+ const struct sshbuf *server_kexinit, const struct sshbuf *server_host_key_blob,
+ const struct sshbuf *client_pub, const struct sshbuf *server_pub,
+ const struct sshbuf *shared_secret, u_char *hash, size_t *hashlen);
+
void kexc25519_keygen(u_char key[CURVE25519_SIZE], u_char pub[CURVE25519_SIZE])
__attribute__((__bounded__(__minbytes__, 1, CURVE25519_SIZE)))
__attribute__((__bounded__(__minbytes__, 2, CURVE25519_SIZE)));
diff --color -ruNp a/kex-names.c b/kex-names.c
--- a/kex-names.c 2024-07-01 06:36:28.000000000 +0200
+++ b/kex-names.c 2024-09-16 11:46:34.694939883 +0200
@@ -45,6 +45,10 @@
#include "ssherr.h"
#include "xmalloc.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
struct kexalg {
char *name;
u_int type;
@@ -83,15 +87,28 @@ static const struct kexalg kexalgs[] = {
#endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
{ NULL, 0, -1, -1},
};
+static const struct kexalg gss_kexalgs[] = {
+#ifdef GSSAPI
+ { KEX_GSS_GEX_SHA1_ID, KEX_GSS_GEX_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_GSS_GRP1_SHA1_ID, KEX_GSS_GRP1_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_GSS_GRP14_SHA1_ID, KEX_GSS_GRP14_SHA1, 0, SSH_DIGEST_SHA1 },
+ { KEX_GSS_GRP14_SHA256_ID, KEX_GSS_GRP14_SHA256, 0, SSH_DIGEST_SHA256 },
+ { KEX_GSS_GRP16_SHA512_ID, KEX_GSS_GRP16_SHA512, 0, SSH_DIGEST_SHA512 },
+ { KEX_GSS_NISTP256_SHA256_ID, KEX_GSS_NISTP256_SHA256,
+ NID_X9_62_prime256v1, SSH_DIGEST_SHA256 },
+ { KEX_GSS_C25519_SHA256_ID, KEX_GSS_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
+#endif
+ { NULL, 0, -1, -1},
+};
-char *
-kex_alg_list(char sep)
+static char *
+kex_alg_list_internal(char sep, const struct kexalg *algs)
{
char *ret = NULL, *tmp;
size_t nlen, rlen = 0;
const struct kexalg *k;
- for (k = kexalgs; k->name != NULL; k++) {
+ for (k = algs; k->name != NULL; k++) {
if (ret != NULL)
ret[rlen++] = sep;
nlen = strlen(k->name);
@@ -106,6 +123,18 @@ kex_alg_list(char sep)
return ret;
}
+char *
+kex_alg_list(char sep)
+{
+ return kex_alg_list_internal(sep, kexalgs);
+}
+
+char *
+kex_gss_alg_list(char sep)
+{
+ return kex_alg_list_internal(sep, gss_kexalgs);
+}
+
static const struct kexalg *
kex_alg_by_name(const char *name)
{
@@ -115,6 +144,10 @@ kex_alg_by_name(const char *name)
if (strcmp(k->name, name) == 0)
return k;
}
+ for (k = gss_kexalgs; k->name != NULL; k++) {
+ if (strncmp(k->name, name, strlen(k->name)) == 0)
+ return k;
+ }
return NULL;
}
@@ -328,3 +361,26 @@ kex_assemble_names(char **listp, const c
free(ret);
return r;
}
+
+/* Validate GSS KEX method name list */
+int
+kex_gss_names_valid(const char *names)
+{
+ char *s, *cp, *p;
+
+ if (names == NULL || *names == '\0')
+ return 0;
+ s = cp = xstrdup(names);
+ for ((p = strsep(&cp, ",")); p && *p != '\0';
+ (p = strsep(&cp, ","))) {
+ if (strncmp(p, "gss-", 4) != 0
+ || kex_alg_by_name(p) == NULL) {
+ error("Unsupported KEX algorithm \"%.100s\"", p);
+ free(s);
+ return 0;
+ }
+ }
+ debug3("gss kex names ok: [%s]", names);
+ free(s);
+ return 1;
+}
diff --color -ruNp a/Makefile.in b/Makefile.in
--- a/Makefile.in 2024-09-16 11:45:56.868133454 +0200
+++ b/Makefile.in 2024-09-16 11:46:34.695939904 +0200
@@ -114,6 +114,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
kex.o kex-names.o kexdh.o kexgex.o kexecdh.o kexc25519.o \
kexgexc.o kexgexs.o \
kexsntrup761x25519.o kexmlkem768x25519.o sntrup761.o kexgen.o \
+ kexgssc.o \
sftp-realpath.o platform-pledge.o platform-tracing.o platform-misc.o \
sshbuf-io.o
@@ -135,7 +136,7 @@ SSHD_SESSION_OBJS=sshd-session.o auth-rh
auth2-chall.o groupaccess.o \
auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
auth2-none.o auth2-passwd.o auth2-pubkey.o auth2-pubkeyfile.o \
- monitor.o monitor_wrap.o auth-krb5.o \
+ monitor.o monitor_wrap.o auth-krb5.o kexgsss.o \
auth2-gss.o gss-serv.o gss-serv-krb5.o \
loginrec.o auth-pam.o auth-shadow.o auth-sia.o \
sftp-server.o sftp-common.o \
@@ -529,7 +530,7 @@ regress-prep:
ln -s `cd $(srcdir) && pwd`/regress/Makefile `pwd`/regress/Makefile
REGRESSLIBS=libssh.a $(LIBCOMPAT)
-TESTLIBS=$(LIBS) $(CHANNELLIBS)
+TESTLIBS=$(LIBS) $(CHANNELLIBS) $(GSSLIBS)
regress/modpipe$(EXEEXT): $(srcdir)/regress/modpipe.c $(REGRESSLIBS)
$(CC) $(CFLAGS) $(CPPFLAGS) -o $@ $(srcdir)/regress/modpipe.c \
diff --color -ruNp a/monitor.c b/monitor.c
--- a/monitor.c 2024-09-16 11:45:56.861133305 +0200
+++ b/monitor.c 2024-09-16 11:46:34.696939926 +0200
@@ -143,6 +143,8 @@ int mm_answer_gss_setup_ctx(struct ssh *
int mm_answer_gss_accept_ctx(struct ssh *, int, struct sshbuf *);
int mm_answer_gss_userok(struct ssh *, int, struct sshbuf *);
int mm_answer_gss_checkmic(struct ssh *, int, struct sshbuf *);
+int mm_answer_gss_sign(struct ssh *, int, struct sshbuf *);
+int mm_answer_gss_updatecreds(struct ssh *, int, struct sshbuf *);
#endif
#ifdef SSH_AUDIT_EVENTS
@@ -219,11 +221,18 @@ struct mon_table mon_dispatch_proto20[]
{MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
{MONITOR_REQ_GSSUSEROK, MON_ONCE|MON_AUTHDECIDE, mm_answer_gss_userok},
{MONITOR_REQ_GSSCHECKMIC, MON_ONCE, mm_answer_gss_checkmic},
+ {MONITOR_REQ_GSSSIGN, MON_ONCE, mm_answer_gss_sign},
#endif
{0, 0, NULL}
};
struct mon_table mon_dispatch_postauth20[] = {
+#ifdef GSSAPI
+ {MONITOR_REQ_GSSSETUP, 0, mm_answer_gss_setup_ctx},
+ {MONITOR_REQ_GSSSTEP, 0, mm_answer_gss_accept_ctx},
+ {MONITOR_REQ_GSSSIGN, 0, mm_answer_gss_sign},
+ {MONITOR_REQ_GSSUPCREDS, 0, mm_answer_gss_updatecreds},
+#endif
#ifdef WITH_OPENSSL
{MONITOR_REQ_MODULI, 0, mm_answer_moduli},
#endif
@@ -292,6 +301,10 @@ monitor_child_preauth(struct ssh *ssh, s
/* Permit requests for moduli and signatures */
monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
+#ifdef GSSAPI
+ /* and for the GSSAPI key exchange */
+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
+#endif
/* The first few requests do not require asynchronous access */
while (!authenticated) {
@@ -344,8 +357,15 @@ monitor_child_preauth(struct ssh *ssh, s
if (ent->flags & (MON_AUTHDECIDE|MON_ALOG)) {
auth_log(ssh, authenticated, partial,
auth_method, auth_submethod);
- if (!partial && !authenticated)
+ if (!partial && !authenticated) {
+#ifdef GSSAPI
+ /* If gssapi-with-mic failed, MONITOR_REQ_GSSCHECKMIC is disabled.
+ * We have to reenable it to try again for gssapi-keyex */
+ if (strcmp(auth_method, "gssapi-with-mic") == 0 && options.gss_keyex)
+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
+#endif
authctxt->failures++;
+ }
if (authenticated || partial) {
auth2_update_session_info(authctxt,
auth_method, auth_submethod);
@@ -413,6 +433,10 @@ monitor_child_postauth(struct ssh *ssh,
monitor_permit(mon_dispatch, MONITOR_REQ_MODULI, 1);
monitor_permit(mon_dispatch, MONITOR_REQ_SIGN, 1);
monitor_permit(mon_dispatch, MONITOR_REQ_TERM, 1);
+#ifdef GSSAPI
+ /* and for the GSSAPI key exchange */
+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSETUP, 1);
+#endif
if (auth_opts->permit_pty_flag) {
monitor_permit(mon_dispatch, MONITOR_REQ_PTY, 1);
@@ -1793,6 +1817,17 @@ monitor_apply_keystate(struct ssh *ssh,
# ifdef OPENSSL_HAS_ECC
kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
# endif
+# ifdef GSSAPI
+ if (options.gss_keyex) {
+ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
+ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
+ kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
+ kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
+ kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
+ kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
+ kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
+ }
+# endif
#endif /* WITH_OPENSSL */
kex->kex[KEX_C25519_SHA256] = kex_gen_server;
kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
@@ -1885,8 +1920,8 @@ mm_answer_gss_setup_ctx(struct ssh *ssh,
u_char *p;
int r;
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
if ((r = sshbuf_get_string(m, &p, &len)) != 0)
fatal_fr(r, "parse");
@@ -1918,8 +1953,8 @@ mm_answer_gss_accept_ctx(struct ssh *ssh
OM_uint32 flags = 0; /* GSI needs this */
int r;
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
fatal_fr(r, "ssh_gssapi_get_buffer_desc");
@@ -1939,6 +1974,7 @@ mm_answer_gss_accept_ctx(struct ssh *ssh
monitor_permit(mon_dispatch, MONITOR_REQ_GSSSTEP, 0);
monitor_permit(mon_dispatch, MONITOR_REQ_GSSUSEROK, 1);
monitor_permit(mon_dispatch, MONITOR_REQ_GSSCHECKMIC, 1);
+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSSIGN, 1);
}
return (0);
}
@@ -1950,8 +1986,8 @@ mm_answer_gss_checkmic(struct ssh *ssh,
OM_uint32 ret;
int r;
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
(r = ssh_gssapi_get_buffer_desc(m, &mic)) != 0)
@@ -1977,13 +2013,17 @@ mm_answer_gss_checkmic(struct ssh *ssh,
int
mm_answer_gss_userok(struct ssh *ssh, int sock, struct sshbuf *m)
{
- int r, authenticated;
+ int r, authenticated, kex;
const char *displayname;
- if (!options.gss_authentication)
- fatal_f("GSSAPI authentication not enabled");
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
- authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
+ if ((r = sshbuf_get_u32(m, &kex)) != 0)
+ fatal_fr(r, "buffer error");
+
+ authenticated = authctxt->valid &&
+ ssh_gssapi_userok(authctxt->user, authctxt->pw, kex);
sshbuf_reset(m);
if ((r = sshbuf_put_u32(m, authenticated)) != 0)
@@ -1992,7 +2032,11 @@ mm_answer_gss_userok(struct ssh *ssh, in
debug3_f("sending result %d", authenticated);
mm_request_send(sock, MONITOR_ANS_GSSUSEROK, m);
- auth_method = "gssapi-with-mic";
+ if (kex) {
+ auth_method = "gssapi-keyex";
+ } else {
+ auth_method = "gssapi-with-mic";
+ }
if ((displayname = ssh_gssapi_displayname()) != NULL)
auth2_record_info(authctxt, "%s", displayname);
@@ -2000,5 +2044,84 @@ mm_answer_gss_userok(struct ssh *ssh, in
/* Monitor loop will terminate if authenticated */
return (authenticated);
}
+
+int
+mm_answer_gss_sign(struct ssh *ssh, int socket, struct sshbuf *m)
+{
+ gss_buffer_desc data;
+ gss_buffer_desc hash = GSS_C_EMPTY_BUFFER;
+ OM_uint32 major, minor;
+ size_t len;
+ u_char *p = NULL;
+ int r;
+
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
+
+ if ((r = sshbuf_get_string(m, &p, &len)) != 0)
+ fatal_fr(r, "buffer error");
+ data.value = p;
+ data.length = len;
+ /* Lengths of SHA-1, SHA-256 and SHA-512 hashes that are used */
+ if (data.length != 20 && data.length != 32 && data.length != 64)
+ fatal_f("data length incorrect: %d", (int) data.length);
+
+ /* Save the session ID on the first time around */
+ if (session_id2_len == 0) {
+ session_id2_len = data.length;
+ session_id2 = xmalloc(session_id2_len);
+ memcpy(session_id2, data.value, session_id2_len);
+ }
+ major = ssh_gssapi_sign(gsscontext, &data, &hash);
+
+ free(data.value);
+
+ sshbuf_reset(m);
+
+ if ((r = sshbuf_put_u32(m, major)) != 0 ||
+ (r = sshbuf_put_string(m, hash.value, hash.length)) != 0)
+ fatal_fr(r, "buffer error");
+
+ mm_request_send(socket, MONITOR_ANS_GSSSIGN, m);
+
+ gss_release_buffer(&minor, &hash);
+
+ /* Turn on getpwnam permissions */
+ monitor_permit(mon_dispatch, MONITOR_REQ_PWNAM, 1);
+
+ /* And credential updating, for when rekeying */
+ monitor_permit(mon_dispatch, MONITOR_REQ_GSSUPCREDS, 1);
+
+ return (0);
+}
+
+int
+mm_answer_gss_updatecreds(struct ssh *ssh, int socket, struct sshbuf *m) {
+ ssh_gssapi_ccache store;
+ int r, ok;
+
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal_f("GSSAPI not enabled");
+
+ if ((r = sshbuf_get_string(m, (u_char **)&store.filename, NULL)) != 0 ||
+ (r = sshbuf_get_string(m, (u_char **)&store.envvar, NULL)) != 0 ||
+ (r = sshbuf_get_string(m, (u_char **)&store.envval, NULL)) != 0)
+ fatal_fr(r, "buffer error");
+
+ ok = ssh_gssapi_update_creds(&store);
+
+ free(store.filename);
+ free(store.envvar);
+ free(store.envval);
+
+ sshbuf_reset(m);
+ if ((r = sshbuf_put_u32(m, ok)) != 0)
+ fatal_fr(r, "buffer error");
+
+ mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
+
+ return(0);
+}
+
#endif /* GSSAPI */
diff --color -ruNp a/monitor.h b/monitor.h
--- a/monitor.h 2024-09-16 11:45:56.861133305 +0200
+++ b/monitor.h 2024-09-16 11:46:34.696939926 +0200
@@ -67,6 +67,8 @@ enum monitor_reqtype {
MONITOR_REQ_PAM_FREE_CTX = 110, MONITOR_ANS_PAM_FREE_CTX = 111,
MONITOR_REQ_AUDIT_EVENT = 112, MONITOR_REQ_AUDIT_COMMAND = 113,
+ MONITOR_REQ_GSSSIGN = 150, MONITOR_ANS_GSSSIGN = 151,
+ MONITOR_REQ_GSSUPCREDS = 152, MONITOR_ANS_GSSUPCREDS = 153,
};
struct ssh;
diff --color -ruNp a/monitor_wrap.c b/monitor_wrap.c
--- a/monitor_wrap.c 2024-09-16 11:45:56.862133326 +0200
+++ b/monitor_wrap.c 2024-09-16 11:46:34.697939947 +0200
@@ -1075,13 +1075,15 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss
}
int
-mm_ssh_gssapi_userok(char *user)
+mm_ssh_gssapi_userok(char *user, struct passwd *pw, int kex)
{
struct sshbuf *m;
int r, authenticated = 0;
if ((m = sshbuf_new()) == NULL)
fatal_f("sshbuf_new failed");
+ if ((r = sshbuf_put_u32(m, kex)) != 0)
+ fatal_fr(r, "buffer error");
mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUSEROK, m);
mm_request_receive_expect(pmonitor->m_recvfd,
@@ -1094,6 +1096,59 @@ mm_ssh_gssapi_userok(char *user)
debug3_f("user %sauthenticated", authenticated ? "" : "not ");
return (authenticated);
}
+
+OM_uint32
+mm_ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *data, gss_buffer_desc *hash)
+{
+ struct sshbuf *m;
+ OM_uint32 major;
+ int r;
+
+ if ((m = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+ if ((r = sshbuf_put_string(m, data->value, data->length)) != 0)
+ fatal_fr(r, "buffer error");
+
+ mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSSIGN, m);
+ mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSSIGN, m);
+
+ if ((r = sshbuf_get_u32(m, &major)) != 0 ||
+ (r = ssh_gssapi_get_buffer_desc(m, hash)) != 0)
+ fatal_fr(r, "buffer error");
+
+ sshbuf_free(m);
+
+ return (major);
+}
+
+int
+mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store)
+{
+ struct sshbuf *m;
+ int r, ok;
+
+ if ((m = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ if ((r = sshbuf_put_cstring(m,
+ store->filename ? store->filename : "")) != 0 ||
+ (r = sshbuf_put_cstring(m,
+ store->envvar ? store->envvar : "")) != 0 ||
+ (r = sshbuf_put_cstring(m,
+ store->envval ? store->envval : "")) != 0)
+ fatal_fr(r, "buffer error");
+
+ mm_request_send(pmonitor->m_recvfd, MONITOR_REQ_GSSUPCREDS, m);
+ mm_request_receive_expect(pmonitor->m_recvfd, MONITOR_ANS_GSSUPCREDS, m);
+
+ if ((r = sshbuf_get_u32(m, &ok)) != 0)
+ fatal_fr(r, "buffer error");
+
+ sshbuf_free(m);
+
+ return (ok);
+}
+
#endif /* GSSAPI */
/*
diff --color -ruNp a/monitor_wrap.h b/monitor_wrap.h
--- a/monitor_wrap.h 2024-09-16 11:45:56.862133326 +0200
+++ b/monitor_wrap.h 2024-09-16 11:46:34.697939947 +0200
@@ -67,8 +67,10 @@ void mm_decode_activate_server_options(s
OM_uint32 mm_ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
OM_uint32 mm_ssh_gssapi_accept_ctx(Gssctxt *,
gss_buffer_desc *, gss_buffer_desc *, OM_uint32 *);
-int mm_ssh_gssapi_userok(char *user);
+int mm_ssh_gssapi_userok(char *user, struct passwd *, int kex);
OM_uint32 mm_ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
+OM_uint32 mm_ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
+int mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *);
#endif
#ifdef USE_PAM
diff --color -ruNp a/readconf.c b/readconf.c
--- a/readconf.c 2024-07-01 06:36:28.000000000 +0200
+++ b/readconf.c 2024-09-16 11:46:34.699939990 +0200
@@ -70,6 +70,7 @@
#include "uidswap.h"
#include "myproposal.h"
#include "digest.h"
+#include "ssh-gss.h"
/* Format of the configuration file:
@@ -164,6 +165,8 @@ typedef enum {
oClearAllForwardings, oNoHostAuthenticationForLocalhost,
oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
oAddressFamily, oGssAuthentication, oGssDelegateCreds,
+ oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
+ oGssServerIdentity, oGssKexAlgorithms,
oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
oHashKnownHosts,
@@ -210,10 +213,22 @@ static struct {
/* Sometimes-unsupported options */
#if defined(GSSAPI)
{ "gssapiauthentication", oGssAuthentication },
+ { "gssapikeyexchange", oGssKeyEx },
{ "gssapidelegatecredentials", oGssDelegateCreds },
+ { "gssapitrustdns", oGssTrustDns },
+ { "gssapiclientidentity", oGssClientIdentity },
+ { "gssapiserveridentity", oGssServerIdentity },
+ { "gssapirenewalforcesrekey", oGssRenewalRekey },
+ { "gssapikexalgorithms", oGssKexAlgorithms },
# else
{ "gssapiauthentication", oUnsupported },
+ { "gssapikeyexchange", oUnsupported },
{ "gssapidelegatecredentials", oUnsupported },
+ { "gssapitrustdns", oUnsupported },
+ { "gssapiclientidentity", oUnsupported },
+ { "gssapiserveridentity", oUnsupported },
+ { "gssapirenewalforcesrekey", oUnsupported },
+ { "gssapikexalgorithms", oUnsupported },
#endif
#ifdef ENABLE_PKCS11
{ "pkcs11provider", oPKCS11Provider },
@@ -1227,10 +1242,42 @@ parse_time:
intptr = &options->gss_authentication;
goto parse_flag;
+ case oGssKeyEx:
+ intptr = &options->gss_keyex;
+ goto parse_flag;
+
case oGssDelegateCreds:
intptr = &options->gss_deleg_creds;
goto parse_flag;
+ case oGssTrustDns:
+ intptr = &options->gss_trust_dns;
+ goto parse_flag;
+
+ case oGssClientIdentity:
+ charptr = &options->gss_client_identity;
+ goto parse_string;
+
+ case oGssServerIdentity:
+ charptr = &options->gss_server_identity;
+ goto parse_string;
+
+ case oGssRenewalRekey:
+ intptr = &options->gss_renewal_rekey;
+ goto parse_flag;
+
+ case oGssKexAlgorithms:
+ arg = argv_next(&ac, &av);
+ if (!arg || *arg == '\0')
+ fatal("%.200s line %d: Missing argument.",
+ filename, linenum);
+ if (!kex_gss_names_valid(arg))
+ fatal("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
+ filename, linenum, arg ? arg : "<NONE>");
+ if (*activep && options->gss_kex_algorithms == NULL)
+ options->gss_kex_algorithms = xstrdup(arg);
+ break;
+
case oBatchMode:
intptr = &options->batch_mode;
goto parse_flag;
@@ -2542,7 +2589,13 @@ initialize_options(Options * options)
options->fwd_opts.streamlocal_bind_unlink = -1;
options->pubkey_authentication = -1;
options->gss_authentication = -1;
+ options->gss_keyex = -1;
options->gss_deleg_creds = -1;
+ options->gss_trust_dns = -1;
+ options->gss_renewal_rekey = -1;
+ options->gss_client_identity = NULL;
+ options->gss_server_identity = NULL;
+ options->gss_kex_algorithms = NULL;
options->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->kbd_interactive_devices = NULL;
@@ -2705,8 +2758,18 @@ fill_default_options(Options * options)
options->pubkey_authentication = SSH_PUBKEY_AUTH_ALL;
if (options->gss_authentication == -1)
options->gss_authentication = 0;
+ if (options->gss_keyex == -1)
+ options->gss_keyex = 0;
if (options->gss_deleg_creds == -1)
options->gss_deleg_creds = 0;
+ if (options->gss_trust_dns == -1)
+ options->gss_trust_dns = 0;
+ if (options->gss_renewal_rekey == -1)
+ options->gss_renewal_rekey = 0;
+#ifdef GSSAPI
+ if (options->gss_kex_algorithms == NULL)
+ options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
+#endif
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
@@ -3533,7 +3596,14 @@ dump_client_config(Options *o, const cha
dump_cfg_fmtint(oGatewayPorts, o->fwd_opts.gateway_ports);
#ifdef GSSAPI
dump_cfg_fmtint(oGssAuthentication, o->gss_authentication);
+ dump_cfg_fmtint(oGssKeyEx, o->gss_keyex);
dump_cfg_fmtint(oGssDelegateCreds, o->gss_deleg_creds);
+ dump_cfg_fmtint(oGssTrustDns, o->gss_trust_dns);
+ dump_cfg_fmtint(oGssRenewalRekey, o->gss_renewal_rekey);
+ dump_cfg_string(oGssClientIdentity, o->gss_client_identity);
+ dump_cfg_string(oGssServerIdentity, o->gss_server_identity);
+ dump_cfg_string(oGssKexAlgorithms, o->gss_kex_algorithms ?
+ o->gss_kex_algorithms : GSS_KEX_DEFAULT_KEX);
#endif /* GSSAPI */
dump_cfg_fmtint(oHashKnownHosts, o->hash_known_hosts);
dump_cfg_fmtint(oHostbasedAuthentication, o->hostbased_authentication);
diff --color -ruNp a/readconf.h b/readconf.h
--- a/readconf.h 2024-07-01 06:36:28.000000000 +0200
+++ b/readconf.h 2024-09-16 11:46:34.699939990 +0200
@@ -40,7 +40,13 @@ typedef struct {
int pubkey_authentication; /* Try ssh2 pubkey authentication. */
int hostbased_authentication; /* ssh2's rhosts_rsa */
int gss_authentication; /* Try GSS authentication */
+ int gss_keyex; /* Try GSS key exchange */
int gss_deleg_creds; /* Delegate GSS credentials */
+ int gss_trust_dns; /* Trust DNS for GSS canonicalization */
+ int gss_renewal_rekey; /* Credential renewal forces rekey */
+ char *gss_client_identity; /* Principal to initiate GSSAPI with */
+ char *gss_server_identity; /* GSSAPI target principal */
+ char *gss_kex_algorithms; /* GSSAPI kex methods to be offered by client. */
int password_authentication; /* Try password
* authentication. */
int kbd_interactive_authentication; /* Try keyboard-interactive auth. */
diff --color -ruNp a/servconf.c b/servconf.c
--- a/servconf.c 2024-07-01 06:36:28.000000000 +0200
+++ b/servconf.c 2024-09-16 11:46:34.700940011 +0200
@@ -68,6 +68,7 @@
#include "auth.h"
#include "myproposal.h"
#include "digest.h"
+#include "ssh-gss.h"
#if !defined(SSHD_PAM_SERVICE)
# define SSHD_PAM_SERVICE "sshd"
@@ -137,8 +138,11 @@ initialize_server_options(ServerOptions
options->kerberos_ticket_cleanup = -1;
options->kerberos_get_afs_token = -1;
options->gss_authentication=-1;
+ options->gss_keyex = -1;
options->gss_cleanup_creds = -1;
options->gss_strict_acceptor = -1;
+ options->gss_store_rekey = -1;
+ options->gss_kex_algorithms = NULL;
options->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->permit_empty_passwd = -1;
@@ -376,10 +380,18 @@ fill_default_server_options(ServerOption
options->kerberos_get_afs_token = 0;
if (options->gss_authentication == -1)
options->gss_authentication = 0;
+ if (options->gss_keyex == -1)
+ options->gss_keyex = 0;
if (options->gss_cleanup_creds == -1)
options->gss_cleanup_creds = 1;
if (options->gss_strict_acceptor == -1)
options->gss_strict_acceptor = 1;
+ if (options->gss_store_rekey == -1)
+ options->gss_store_rekey = 0;
+#ifdef GSSAPI
+ if (options->gss_kex_algorithms == NULL)
+ options->gss_kex_algorithms = strdup(GSS_KEX_DEFAULT_KEX);
+#endif
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
@@ -558,6 +570,7 @@ typedef enum {
sPerSourcePenalties, sPerSourcePenaltyExemptList,
sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
+ sGssKeyEx, sGssKexAlgorithms, sGssStoreRekey,
sAcceptEnv, sSetEnv, sPermitTunnel,
sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
sUsePrivilegeSeparation, sAllowAgentForwarding,
@@ -643,12 +656,22 @@ static struct {
#ifdef GSSAPI
{ "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
{ "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
+ { "gssapicleanupcreds", sGssCleanupCreds, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
+ { "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL },
+ { "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL },
+ { "gssapikexalgorithms", sGssKexAlgorithms, SSHCFG_GLOBAL },
#else
{ "gssapiauthentication", sUnsupported, SSHCFG_ALL },
{ "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapicleanupcreds", sUnsupported, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapikexalgorithms", sUnsupported, SSHCFG_GLOBAL },
#endif
+ { "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
{ "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
{ "challengeresponseauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL }, /* alias */
@@ -1585,6 +1608,10 @@ process_server_config_line_depth(ServerO
intptr = &options->gss_authentication;
goto parse_flag;
+ case sGssKeyEx:
+ intptr = &options->gss_keyex;
+ goto parse_flag;
+
case sGssCleanupCreds:
intptr = &options->gss_cleanup_creds;
goto parse_flag;
@@ -1593,6 +1620,22 @@ process_server_config_line_depth(ServerO
intptr = &options->gss_strict_acceptor;
goto parse_flag;
+ case sGssStoreRekey:
+ intptr = &options->gss_store_rekey;
+ goto parse_flag;
+
+ case sGssKexAlgorithms:
+ arg = argv_next(&ac, &av);
+ if (!arg || *arg == '\0')
+ fatal("%.200s line %d: Missing argument.",
+ filename, linenum);
+ if (!kex_gss_names_valid(arg))
+ fatal("%.200s line %d: Bad GSSAPI KexAlgorithms '%s'.",
+ filename, linenum, arg ? arg : "<NONE>");
+ if (*activep && options->gss_kex_algorithms == NULL)
+ options->gss_kex_algorithms = xstrdup(arg);
+ break;
+
case sPasswordAuthentication:
intptr = &options->password_authentication;
goto parse_flag;
@@ -3178,6 +3221,10 @@ dump_config(ServerOptions *o)
#ifdef GSSAPI
dump_cfg_fmtint(sGssAuthentication, o->gss_authentication);
dump_cfg_fmtint(sGssCleanupCreds, o->gss_cleanup_creds);
+ dump_cfg_fmtint(sGssKeyEx, o->gss_keyex);
+ dump_cfg_fmtint(sGssStrictAcceptor, o->gss_strict_acceptor);
+ dump_cfg_fmtint(sGssStoreRekey, o->gss_store_rekey);
+ dump_cfg_string(sGssKexAlgorithms, o->gss_kex_algorithms);
#endif
dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
dump_cfg_fmtint(sKbdInteractiveAuthentication,
diff --color -ruNp a/servconf.h b/servconf.h
--- a/servconf.h 2024-07-01 06:36:28.000000000 +0200
+++ b/servconf.h 2024-09-16 11:46:34.700940011 +0200
@@ -149,8 +149,11 @@ typedef struct {
int kerberos_get_afs_token; /* If true, try to get AFS token if
* authenticated with Kerberos. */
int gss_authentication; /* If true, permit GSSAPI authentication */
+ int gss_keyex; /* If true, permit GSSAPI key exchange */
int gss_cleanup_creds; /* If true, destroy cred cache on logout */
int gss_strict_acceptor; /* If true, restrict the GSSAPI acceptor name */
+ int gss_store_rekey;
+ char *gss_kex_algorithms; /* GSSAPI kex methods to be offered by client. */
int password_authentication; /* If true, permit password
* authentication. */
int kbd_interactive_authentication; /* If true, permit */
diff --color -ruNp a/session.c b/session.c
--- a/session.c 2024-09-16 11:45:56.866133411 +0200
+++ b/session.c 2024-09-16 11:46:34.701940032 +0200
@@ -2674,13 +2674,19 @@ do_cleanup(struct ssh *ssh, Authctxt *au
#ifdef KRB5
if (options.kerberos_ticket_cleanup &&
- authctxt->krb5_ctx)
+ authctxt->krb5_ctx) {
+ temporarily_use_uid(authctxt->pw);
krb5_cleanup_proc(authctxt);
+ restore_uid();
+ }
#endif
#ifdef GSSAPI
- if (options.gss_cleanup_creds)
+ if (options.gss_cleanup_creds) {
+ temporarily_use_uid(authctxt->pw);
ssh_gssapi_cleanup_creds();
+ restore_uid();
+ }
#endif
/* remove agent socket */
diff --color -ruNp a/ssh.1 b/ssh.1
--- a/ssh.1 2024-09-16 11:45:56.875133603 +0200
+++ b/ssh.1 2024-09-16 11:46:34.701940032 +0200
@@ -536,7 +536,13 @@ For full details of the options listed b
.It GatewayPorts
.It GlobalKnownHostsFile
.It GSSAPIAuthentication
+.It GSSAPIKeyExchange
+.It GSSAPIClientIdentity
.It GSSAPIDelegateCredentials
+.It GSSAPIKexAlgorithms
+.It GSSAPIRenewalForcesRekey
+.It GSSAPIServerIdentity
+.It GSSAPITrustDns
.It HashKnownHosts
.It Host
.It HostbasedAcceptedAlgorithms
@@ -624,6 +630,8 @@ flag),
(supported message integrity codes),
.Ar kex
(key exchange algorithms),
+.Ar kex-gss
+(GSSAPI key exchange algorithms),
.Ar key
(key types),
.Ar key-ca-sign
diff --color -ruNp a/ssh.c b/ssh.c
--- a/ssh.c 2024-07-01 06:36:28.000000000 +0200
+++ b/ssh.c 2024-09-16 11:46:34.702940054 +0200
@@ -827,6 +827,8 @@ main(int ac, char **av)
else if (strcmp(optarg, "kex") == 0 ||
strcasecmp(optarg, "KexAlgorithms") == 0)
cp = kex_alg_list('\n');
+ else if (strcmp(optarg, "kex-gss") == 0)
+ cp = kex_gss_alg_list('\n');
else if (strcmp(optarg, "key") == 0)
cp = sshkey_alg_list(0, 0, 0, '\n');
else if (strcmp(optarg, "key-cert") == 0)
@@ -857,8 +859,8 @@ main(int ac, char **av)
} else if (strcmp(optarg, "help") == 0) {
cp = xstrdup(
"cipher\ncipher-auth\ncompression\nkex\n"
- "key\nkey-cert\nkey-plain\nkey-sig\nmac\n"
- "protocol-version\nsig");
+ "kex-gss\nkey\nkey-cert\nkey-plain\n"
+ "key-sig\nmac\nprotocol-version\nsig");
}
if (cp == NULL)
fatal("Unsupported query \"%s\"", optarg);
diff --color -ruNp a/ssh_config b/ssh_config
--- a/ssh_config 2024-09-16 11:45:56.884133795 +0200
+++ b/ssh_config 2024-09-16 11:46:34.702940054 +0200
@@ -24,6 +24,8 @@
# HostbasedAuthentication no
# GSSAPIAuthentication no
# GSSAPIDelegateCredentials no
+# GSSAPIKeyExchange no
+# GSSAPITrustDNS no
# BatchMode no
# CheckHostIP no
# AddressFamily any
diff --color -ruNp a/ssh_config.5 b/ssh_config.5
--- a/ssh_config.5 2024-07-01 06:36:28.000000000 +0200
+++ b/ssh_config.5 2024-09-16 11:46:34.703940075 +0200
@@ -938,10 +938,68 @@ The default is
Specifies whether user authentication based on GSSAPI is allowed.
The default is
.Cm no .
+.It Cm GSSAPIClientIdentity
+If set, specifies the GSSAPI client identity that ssh should use when
+connecting to the server. The default is unset, which means that the default
+identity will be used.
.It Cm GSSAPIDelegateCredentials
Forward (delegate) credentials to the server.
The default is
.Cm no .
+.It Cm GSSAPIKeyExchange
+Specifies whether key exchange based on GSSAPI may be used. When using
+GSSAPI key exchange the server need not have a host key.
+The default is
+.Dq no .
+.It Cm GSSAPIRenewalForcesRekey
+If set to
+.Dq yes
+then renewal of the client's GSSAPI credentials will force the rekeying of the
+ssh connection. With a compatible server, this will delegate the renewed
+credentials to a session on the server.
+.Pp
+Checks are made to ensure that credentials are only propagated when the new
+credentials match the old ones on the originating client and where the
+receiving server still has the old set in its cache.
+.Pp
+The default is
+.Dq no .
+.Pp
+For this to work
+.Cm GSSAPIKeyExchange
+needs to be enabled in the server and also used by the client.
+.It Cm GSSAPIServerIdentity
+If set, specifies the GSSAPI server identity that ssh should expect when
+connecting to the server. The default is unset, which means that the
+expected GSSAPI server identity will be determined from the target
+hostname.
+.It Cm GSSAPITrustDns
+Set to
+.Dq yes
+to indicate that the DNS is trusted to securely canonicalize
+the name of the host being connected to. If
+.Dq no ,
+the hostname entered on the
+command line will be passed untouched to the GSSAPI library.
+The default is
+.Dq no .
+.It Cm GSSAPIKexAlgorithms
+The list of key exchange algorithms that are offered for GSSAPI
+key exchange. Possible values are
+.Bd -literal -offset 3n
+gss-gex-sha1-,
+gss-group1-sha1-,
+gss-group14-sha1-,
+gss-group14-sha256-,
+gss-group16-sha512-,
+gss-nistp256-sha256-,
+gss-curve25519-sha256-
+.Ed
+.Pp
+The default is
+.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,
+gss-curve25519-sha256-,gss-group14-sha1-,gss-gex-sha1- .
+This option only applies to connections using GSSAPI.
.It Cm HashKnownHosts
Indicates that
.Xr ssh 1
diff --color -ruNp a/sshconnect2.c b/sshconnect2.c
--- a/sshconnect2.c 2024-07-01 06:36:28.000000000 +0200
+++ b/sshconnect2.c 2024-09-16 11:46:34.703940075 +0200
@@ -222,6 +222,11 @@ ssh_kex2(struct ssh *ssh, char *host, st
char *all_key, *hkalgs = NULL;
int r, use_known_hosts_order = 0;
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+ char *orig = NULL, *gss = NULL;
+ char *gss_host = NULL;
+#endif
+
xxx_host = host;
xxx_hostaddr = hostaddr;
xxx_conn_info = cinfo;
@@ -255,6 +260,42 @@ ssh_kex2(struct ssh *ssh, char *host, st
compression_alg_list(options.compression),
hkalgs ? hkalgs : options.hostkeyalgorithms);
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+ if (options.gss_keyex) {
+ /* Add the GSSAPI mechanisms currently supported on this
+ * client to the key exchange algorithm proposal */
+ orig = myproposal[PROPOSAL_KEX_ALGS];
+
+ if (options.gss_server_identity) {
+ gss_host = xstrdup(options.gss_server_identity);
+ } else if (options.gss_trust_dns) {
+ gss_host = remote_hostname(ssh);
+ /* Fall back to specified host if we are using proxy command
+ * and can not use DNS on that socket */
+ if (strcmp(gss_host, "UNKNOWN") == 0) {
+ free(gss_host);
+ gss_host = xstrdup(host);
+ }
+ } else {
+ gss_host = xstrdup(host);
+ }
+
+ gss = ssh_gssapi_client_mechanisms(gss_host,
+ options.gss_client_identity, options.gss_kex_algorithms);
+ if (gss) {
+ debug("Offering GSSAPI proposal: %s", gss);
+ xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
+ "%s,%s", gss, orig);
+
+ /* If we've got GSSAPI algorithms, then we also support the
+ * 'null' hostkey, as a last resort */
+ orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
+ xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
+ "%s,null", orig);
+ }
+ }
+#endif
+
free(hkalgs);
/* start key exchange */
@@ -271,15 +312,45 @@ ssh_kex2(struct ssh *ssh, char *host, st
# ifdef OPENSSL_HAS_ECC
ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
# endif
-#endif
+# ifdef GSSAPI
+ if (options.gss_keyex) {
+ ssh->kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
+ ssh->kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
+ ssh->kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_client;
+ ssh->kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_client;
+ ssh->kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_client;
+ ssh->kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_client;
+ ssh->kex->kex[KEX_GSS_C25519_SHA256] = kexgss_client;
+ }
+# endif
+#endif /* WITH_OPENSSL */
ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
ssh->kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_client;
ssh->kex->verify_host_key=&verify_host_key_callback;
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+ if (options.gss_keyex) {
+ ssh->kex->gss_deleg_creds = options.gss_deleg_creds;
+ ssh->kex->gss_trust_dns = options.gss_trust_dns;
+ ssh->kex->gss_client = options.gss_client_identity;
+ ssh->kex->gss_host = gss_host;
+ }
+#endif
+
ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done);
kex_proposal_free_entries(myproposal);
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+ /* repair myproposal after it was crumpled by the */
+ /* ext-info removal above */
+ if (gss) {
+ orig = myproposal[PROPOSAL_KEX_ALGS];
+ xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
+ "%s,%s", gss, orig);
+ free(gss);
+ }
+#endif
#ifdef DEBUG_KEXDH
/* send 1st encrypted/maced/compressed message */
if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 ||
@@ -368,6 +439,7 @@ static int input_gssapi_response(int typ
static int input_gssapi_token(int type, u_int32_t, struct ssh *);
static int input_gssapi_error(int, u_int32_t, struct ssh *);
static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
+static int userauth_gsskeyex(struct ssh *);
#endif
void userauth(struct ssh *, char *);
@@ -384,6 +456,11 @@ static char *authmethods_get(void);
Authmethod authmethods[] = {
#ifdef GSSAPI
+ {"gssapi-keyex",
+ userauth_gsskeyex,
+ NULL,
+ &options.gss_keyex,
+ NULL},
{"gssapi-with-mic",
userauth_gssapi,
userauth_gssapi_cleanup,
@@ -755,12 +832,32 @@ userauth_gssapi(struct ssh *ssh)
OM_uint32 min;
int r, ok = 0;
gss_OID mech = NULL;
+ char *gss_host = NULL;
+
+ if (options.gss_server_identity) {
+ gss_host = xstrdup(options.gss_server_identity);
+ } else if (options.gss_trust_dns) {
+ gss_host = remote_hostname(ssh);
+ /* Fall back to specified host if we are using proxy command
+ * and can not use DNS on that socket */
+ if (strcmp(gss_host, "UNKNOWN") == 0) {
+ free(gss_host);
+ gss_host = xstrdup(authctxt->host);
+ }
+ } else {
+ gss_host = xstrdup(authctxt->host);
+ }
/* Try one GSSAPI method at a time, rather than sending them all at
* once. */
if (authctxt->gss_supported_mechs == NULL)
- gss_indicate_mechs(&min, &authctxt->gss_supported_mechs);
+ if (GSS_ERROR(gss_indicate_mechs(&min,
+ &authctxt->gss_supported_mechs))) {
+ authctxt->gss_supported_mechs = NULL;
+ free(gss_host);
+ return 0;
+ }
/* Check to see whether the mechanism is usable before we offer it */
while (authctxt->mech_tried < authctxt->gss_supported_mechs->count &&
@@ -769,13 +866,15 @@ userauth_gssapi(struct ssh *ssh)
elements[authctxt->mech_tried];
/* My DER encoding requires length<128 */
if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt,
- mech, authctxt->host)) {
+ mech, gss_host, options.gss_client_identity)) {
ok = 1; /* Mechanism works */
} else {
authctxt->mech_tried++;
}
}
+ free(gss_host);
+
if (!ok || mech == NULL)
return 0;
@@ -1009,6 +1108,55 @@ input_gssapi_error(int type, u_int32_t p
free(lang);
return r;
}
+
+int
+userauth_gsskeyex(struct ssh *ssh)
+{
+ struct sshbuf *b = NULL;
+ Authctxt *authctxt = ssh->authctxt;
+ gss_buffer_desc gssbuf;
+ gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ms;
+ int r;
+
+ static int attempt = 0;
+ if (attempt++ >= 1)
+ return (0);
+
+ if (gss_kex_context == NULL) {
+ debug("No valid Key exchange context");
+ return (0);
+ }
+
+ if ((b = sshbuf_new()) == NULL)
+ fatal_f("sshbuf_new failed");
+
+ ssh_gssapi_buildmic(b, authctxt->server_user, authctxt->service,
+ "gssapi-keyex", ssh->kex->session_id);
+
+ if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL)
+ fatal_f("sshbuf_mutable_ptr failed");
+ gssbuf.length = sshbuf_len(b);
+
+ if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
+ sshbuf_free(b);
+ return (0);
+ }
+
+ if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
+ (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
+ (r = sshpkt_put_string(ssh, mic.value, mic.length)) != 0 ||
+ (r = sshpkt_send(ssh)) != 0)
+ fatal_fr(r, "parsing");
+
+ sshbuf_free(b);
+ gss_release_buffer(&ms, &mic);
+
+ return (1);
+}
+
#endif /* GSSAPI */
static int
diff --color -ruNp a/sshd.c b/sshd.c
--- a/sshd.c 2024-07-01 06:36:28.000000000 +0200
+++ b/sshd.c 2024-09-16 11:46:34.704940096 +0200
@@ -1551,7 +1551,8 @@ main(int ac, char **av)
free(fp);
}
accumulate_host_timing_secret(cfg, NULL);
- if (!sensitive_data.have_ssh2_key) {
+ /* The GSSAPI key exchange can run without a host key */
+ if (!sensitive_data.have_ssh2_key && !options.gss_keyex) {
logit("sshd: no hostkeys available -- exiting.");
exit(1);
}
diff --color -ruNp a/sshd_config b/sshd_config
--- a/sshd_config 2024-09-16 11:45:56.888133880 +0200
+++ b/sshd_config 2024-09-16 11:46:34.704940096 +0200
@@ -77,6 +77,8 @@ AuthorizedKeysFile .ssh/authorized_keys
# GSSAPI options
#GSSAPIAuthentication no
#GSSAPICleanupCredentials yes
+#GSSAPIStrictAcceptorCheck yes
+#GSSAPIKeyExchange no
# Set this to 'yes' to enable PAM authentication, account processing,
# and session processing. If this is enabled, PAM authentication will
diff --color -ruNp a/sshd_config.5 b/sshd_config.5
--- a/sshd_config.5 2024-09-16 11:45:56.885133816 +0200
+++ b/sshd_config.5 2024-09-16 11:46:34.704940096 +0200
@@ -739,6 +739,11 @@ Specifies whether to automatically destr
on logout.
The default is
.Cm yes .
+.It Cm GSSAPIKeyExchange
+Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange
+doesn't rely on ssh keys to verify host identity.
+The default is
+.Cm no .
.It Cm GSSAPIStrictAcceptorCheck
Determines whether to be strict about the identity of the GSSAPI acceptor
a client authenticates against.
@@ -753,6 +758,32 @@ machine's default store.
This facility is provided to assist with operation on multi homed machines.
The default is
.Cm yes .
+.It Cm GSSAPIStoreCredentialsOnRekey
+Controls whether the user's GSSAPI credentials should be updated following a
+successful connection rekeying. This option can be used to accepted renewed
+or updated credentials from a compatible client. The default is
+.Dq no .
+.Pp
+For this to work
+.Cm GSSAPIKeyExchange
+needs to be enabled in the server and also used by the client.
+.It Cm GSSAPIKexAlgorithms
+The list of key exchange algorithms that are accepted by GSSAPI
+key exchange. Possible values are
+.Bd -literal -offset 3n
+gss-gex-sha1-,
+gss-group1-sha1-,
+gss-group14-sha1-,
+gss-group14-sha256-,
+gss-group16-sha512-,
+gss-nistp256-sha256-,
+gss-curve25519-sha256-
+.Ed
+.Pp
+The default is
+.Dq gss-group14-sha256-,gss-group16-sha512-,gss-nistp256-sha256-,
+gss-curve25519-sha256-,gss-group14-sha1-,gss-gex-sha1- .
+This option only applies to connections using GSSAPI.
.It Cm HostbasedAcceptedAlgorithms
Specifies the signature algorithms that will be accepted for hostbased
authentication as a list of comma-separated patterns.
diff --color -ruNp a/sshd-session.c b/sshd-session.c
--- a/sshd-session.c 2024-09-16 11:45:56.888133880 +0200
+++ b/sshd-session.c 2024-09-16 11:46:34.705940118 +0200
@@ -660,8 +660,8 @@ notify_hostkeys(struct ssh *ssh)
}
debug3_f("sent %u hostkeys", nkeys);
if (nkeys == 0)
- fatal_f("no hostkeys");
- if ((r = sshpkt_send(ssh)) != 0)
+ debug3_f("no hostkeys");
+ else if ((r = sshpkt_send(ssh)) != 0)
sshpkt_fatal(ssh, r, "%s: send", __func__);
sshbuf_free(buf);
}
@@ -1180,8 +1180,9 @@ main(int ac, char **av)
break;
}
}
- if (!have_key)
- fatal("internal error: monitor received no hostkeys");
+ /* The GSSAPI key exchange can run without a host key */
+ if (!have_key && !options.gss_keyex)
+ fatal("internal error: monitor received no hostkeys and GSS KEX is not configured");
/* Ensure that umask disallows at least group and world write */
new_umask = umask(0077) | 0022;
@@ -1462,6 +1463,48 @@ do_ssh2_kex(struct ssh *ssh)
free(hkalgs);
+#if defined(GSSAPI) && defined(WITH_OPENSSL)
+ {
+ char *orig;
+ char *gss = NULL;
+ char *newstr = NULL;
+ orig = myproposal[PROPOSAL_KEX_ALGS];
+
+ /*
+ * If we don't have a host key, then there's no point advertising
+ * the other key exchange algorithms
+ */
+
+ if (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]) == 0)
+ orig = NULL;
+
+ if (options.gss_keyex)
+ gss = ssh_gssapi_server_mechanisms();
+ else
+ gss = NULL;
+
+ if (gss && orig)
+ xasprintf(&newstr, "%s,%s", gss, orig);
+ else if (gss)
+ xasprintf(&newstr, "%s,%s", gss, "kex-strict-s-v00@openssh.com");
+ else if (orig)
+ newstr = orig;
+
+ /*
+ * If we've got GSSAPI mechanisms, then we've got the 'null' host
+ * key alg, but we can't tell people about it unless its the only
+ * host key algorithm we support
+ */
+ if (gss && (strlen(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS])) == 0)
+ myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = xstrdup("null");
+
+ if (newstr)
+ myproposal[PROPOSAL_KEX_ALGS] = newstr;
+ else
+ fatal("No supported key exchange algorithms");
+ }
+#endif
+
/* start key exchange */
if ((r = kex_setup(ssh, myproposal)) != 0)
fatal_r(r, "kex_setup");
@@ -1479,7 +1522,18 @@ do_ssh2_kex(struct ssh *ssh)
#ifdef OPENSSL_HAS_ECC
kex->kex[KEX_ECDH_SHA2] = kex_gen_server;
#endif
-#endif
+# ifdef GSSAPI
+ if (options.gss_keyex) {
+ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_server;
+ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_server;
+ kex->kex[KEX_GSS_GRP14_SHA256] = kexgss_server;
+ kex->kex[KEX_GSS_GRP16_SHA512] = kexgss_server;
+ kex->kex[KEX_GSS_GEX_SHA1] = kexgssgex_server;
+ kex->kex[KEX_GSS_NISTP256_SHA256] = kexgss_server;
+ kex->kex[KEX_GSS_C25519_SHA256] = kexgss_server;
+ }
+# endif
+#endif /* WITH_OPENSSL */
kex->kex[KEX_C25519_SHA256] = kex_gen_server;
kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_server;
kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_server;
diff --color -ruNp a/ssh-gss.h b/ssh-gss.h
--- a/ssh-gss.h 2024-07-01 06:36:28.000000000 +0200
+++ b/ssh-gss.h 2024-09-16 11:46:34.710940224 +0200
@@ -61,10 +61,36 @@
#define SSH_GSS_OIDTYPE 0x06
+#define SSH2_MSG_KEXGSS_INIT 30
+#define SSH2_MSG_KEXGSS_CONTINUE 31
+#define SSH2_MSG_KEXGSS_COMPLETE 32
+#define SSH2_MSG_KEXGSS_HOSTKEY 33
+#define SSH2_MSG_KEXGSS_ERROR 34
+#define SSH2_MSG_KEXGSS_GROUPREQ 40
+#define SSH2_MSG_KEXGSS_GROUP 41
+#define KEX_GSS_GRP1_SHA1_ID "gss-group1-sha1-"
+#define KEX_GSS_GRP14_SHA1_ID "gss-group14-sha1-"
+#define KEX_GSS_GRP14_SHA256_ID "gss-group14-sha256-"
+#define KEX_GSS_GRP16_SHA512_ID "gss-group16-sha512-"
+#define KEX_GSS_GEX_SHA1_ID "gss-gex-sha1-"
+#define KEX_GSS_NISTP256_SHA256_ID "gss-nistp256-sha256-"
+#define KEX_GSS_C25519_SHA256_ID "gss-curve25519-sha256-"
+
+#define GSS_KEX_DEFAULT_KEX \
+ KEX_GSS_GRP14_SHA256_ID "," \
+ KEX_GSS_GRP16_SHA512_ID "," \
+ KEX_GSS_NISTP256_SHA256_ID "," \
+ KEX_GSS_C25519_SHA256_ID "," \
+ KEX_GSS_GRP14_SHA1_ID "," \
+ KEX_GSS_GEX_SHA1_ID
+
+#include "digest.h" /* SSH_DIGEST_MAX_LENGTH */
+
typedef struct {
char *filename;
char *envvar;
char *envval;
+ struct passwd *owner;
void *data;
} ssh_gssapi_ccache;
@@ -72,8 +98,11 @@ typedef struct {
gss_buffer_desc displayname;
gss_buffer_desc exportedname;
gss_cred_id_t creds;
+ gss_name_t name;
struct ssh_gssapi_mech_struct *mech;
ssh_gssapi_ccache store;
+ int used;
+ int updated;
} ssh_gssapi_client;
typedef struct ssh_gssapi_mech_struct {
@@ -84,6 +113,7 @@ typedef struct ssh_gssapi_mech_struct {
int (*userok) (ssh_gssapi_client *, char *);
int (*localname) (ssh_gssapi_client *, char **);
void (*storecreds) (ssh_gssapi_client *);
+ int (*updatecreds) (ssh_gssapi_ccache *, ssh_gssapi_client *);
} ssh_gssapi_mech;
typedef struct {
@@ -94,10 +124,21 @@ typedef struct {
gss_OID oid; /* client */
gss_cred_id_t creds; /* server */
gss_name_t client; /* server */
- gss_cred_id_t client_creds; /* server */
+ gss_cred_id_t client_creds; /* both */
+ struct sshbuf *shared_secret; /* both */
+ struct sshbuf *server_pubkey; /* server */
+ struct sshbuf *server_blob; /* client */
+ struct sshbuf *server_host_key_blob; /* client */
+ gss_buffer_desc msg_tok; /* client */
+ gss_buffer_desc buf; /* both */
+ u_char hash[SSH_DIGEST_MAX_LENGTH]; /* both */
+ size_t hashlen; /* both */
+ int first; /* client */
+ BIGNUM *dh_client_pub; /* server (gex) */
} Gssctxt;
extern ssh_gssapi_mech *supported_mechs[];
+extern Gssctxt *gss_kex_context;
int ssh_gssapi_check_oid(Gssctxt *, void *, size_t);
void ssh_gssapi_set_oid_data(Gssctxt *, void *, size_t);
@@ -108,6 +149,7 @@ OM_uint32 ssh_gssapi_test_oid_supported(
struct sshbuf;
int ssh_gssapi_get_buffer_desc(struct sshbuf *, gss_buffer_desc *);
+int ssh_gssapi_sshpkt_get_buffer_desc(struct ssh *, gss_buffer_desc *);
OM_uint32 ssh_gssapi_import_name(Gssctxt *, const char *);
OM_uint32 ssh_gssapi_init_ctx(Gssctxt *, int,
@@ -122,17 +164,33 @@ void ssh_gssapi_delete_ctx(Gssctxt **);
OM_uint32 ssh_gssapi_sign(Gssctxt *, gss_buffer_t, gss_buffer_t);
void ssh_gssapi_buildmic(struct sshbuf *, const char *,
const char *, const char *, const struct sshbuf *);
-int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *);
+int ssh_gssapi_check_mechanism(Gssctxt **, gss_OID, const char *, const char *);
+OM_uint32 ssh_gssapi_client_identity(Gssctxt *, const char *);
+int ssh_gssapi_credentials_updated(Gssctxt *);
/* In the server */
+typedef int ssh_gssapi_check_fn(Gssctxt **, gss_OID, const char *,
+ const char *);
+char *ssh_gssapi_client_mechanisms(const char *, const char *, const char *);
+char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, const char *,
+ const char *, const char *);
+gss_OID ssh_gssapi_id_kex(Gssctxt *, char *, int);
+int ssh_gssapi_server_check_mech(Gssctxt **,gss_OID, const char *,
+ const char *);
OM_uint32 ssh_gssapi_server_ctx(Gssctxt **, gss_OID);
-int ssh_gssapi_userok(char *name);
+int ssh_gssapi_userok(char *name, struct passwd *, int kex);
OM_uint32 ssh_gssapi_checkmic(Gssctxt *, gss_buffer_t, gss_buffer_t);
void ssh_gssapi_do_child(char ***, u_int *);
void ssh_gssapi_cleanup_creds(void);
void ssh_gssapi_storecreds(void);
const char *ssh_gssapi_displayname(void);
+char *ssh_gssapi_server_mechanisms(void);
+int ssh_gssapi_oid_table_ok(void);
+
+int ssh_gssapi_update_creds(ssh_gssapi_ccache *store);
+void ssh_gssapi_rekey_creds(void);
+
#endif /* GSSAPI */
#endif /* _SSH_GSS_H */
diff --color -ruNp a/sshkey.c b/sshkey.c
--- a/sshkey.c 2024-07-01 06:36:28.000000000 +0200
+++ b/sshkey.c 2024-09-16 11:46:34.706940139 +0200
@@ -131,6 +131,75 @@ extern const struct sshkey_impl sshkey_x
extern const struct sshkey_impl sshkey_xmss_cert_impl;
#endif
+static int ssh_gss_equal(const struct sshkey *, const struct sshkey *)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_serialize_public(const struct sshkey *, struct sshbuf *,
+ enum sshkey_serialize_rep)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_deserialize_public(const char *, struct sshbuf *,
+ struct sshkey *)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_serialize_private(const struct sshkey *, struct sshbuf *,
+ enum sshkey_serialize_rep)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_deserialize_private(const char *, struct sshbuf *,
+ struct sshkey *)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_copy_public(const struct sshkey *, struct sshkey *)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static int ssh_gss_verify(const struct sshkey *, const u_char *, size_t,
+ const u_char *, size_t, const char *, u_int,
+ struct sshkey_sig_details **)
+{
+ return SSH_ERR_FEATURE_UNSUPPORTED;
+}
+
+static const struct sshkey_impl_funcs sshkey_gss_funcs = {
+ /* .size = */ NULL,
+ /* .alloc = */ NULL,
+ /* .cleanup = */ NULL,
+ /* .equal = */ ssh_gss_equal,
+ /* .ssh_serialize_public = */ ssh_gss_serialize_public,
+ /* .ssh_deserialize_public = */ ssh_gss_deserialize_public,
+ /* .ssh_serialize_private = */ ssh_gss_serialize_private,
+ /* .ssh_deserialize_private = */ ssh_gss_deserialize_private,
+ /* .generate = */ NULL,
+ /* .copy_public = */ ssh_gss_copy_public,
+ /* .sign = */ NULL,
+ /* .verify = */ ssh_gss_verify,
+};
+
+/* The struct is intentionally dummy and has no gss calls */
+static const struct sshkey_impl sshkey_gss_kex_impl = {
+ /* .name = */ "null",
+ /* .shortname = */ "null",
+ /* .sigalg = */ NULL,
+ /* .type = */ KEY_NULL,
+ /* .nid = */ 0,
+ /* .cert = */ 0,
+ /* .sigonly = */ 0,
+ /* .keybits = */ 0, /* FIXME */
+ /* .funcs = */ &sshkey_gss_funcs,
+};
+
const struct sshkey_impl * const keyimpls[] = {
&sshkey_ed25519_impl,
&sshkey_ed25519_cert_impl,
@@ -169,6 +238,7 @@ const struct sshkey_impl * const keyimpl
&sshkey_xmss_impl,
&sshkey_xmss_cert_impl,
#endif
+ &sshkey_gss_kex_impl,
NULL
};
@@ -324,7 +394,7 @@ sshkey_alg_list(int certs_only, int plai
for (i = 0; keyimpls[i] != NULL; i++) {
impl = keyimpls[i];
- if (impl->name == NULL)
+ if (impl->name == NULL || impl->type == KEY_NULL)
continue;
if (!include_sigonly && impl->sigonly)
continue;
diff --color -ruNp a/sshkey.h b/sshkey.h
--- a/sshkey.h 2024-07-01 06:36:28.000000000 +0200
+++ b/sshkey.h 2024-09-16 11:46:34.706940139 +0200
@@ -71,6 +71,7 @@ enum sshkey_types {
KEY_ECDSA_SK_CERT,
KEY_ED25519_SK,
KEY_ED25519_SK_CERT,
+ KEY_NULL,
KEY_UNSPEC
};
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