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openssh/openssh-7.8p1-gsskex.patch

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diff -up openssh/auth2.c.gsskex openssh/auth2.c
--- openssh/auth2.c.gsskex 2018-08-22 11:47:33.260216045 +0200
+++ openssh/auth2.c 2018-08-22 11:47:33.307216424 +0200
@@ -74,6 +74,7 @@ extern Authmethod method_passwd;
extern Authmethod method_kbdint;
extern Authmethod method_hostbased;
#ifdef GSSAPI
+extern Authmethod method_gsskeyex;
extern Authmethod method_gssapi;
#endif
@@ -81,6 +82,7 @@ Authmethod *authmethods[] = {
&method_none,
&method_pubkey,
#ifdef GSSAPI
+ &method_gsskeyex,
&method_gssapi,
#endif
&method_passwd,
diff -up openssh/auth2-gss.c.gsskex openssh/auth2-gss.c
--- openssh/auth2-gss.c.gsskex 2018-08-22 11:47:33.260216045 +0200
+++ openssh/auth2-gss.c 2018-08-22 13:00:48.722680124 +0200
@@ -31,6 +31,7 @@
#include <sys/types.h>
#include <stdarg.h>
+#include <string.h>
#include "xmalloc.h"
#include "sshkey.h"
@@ -54,6 +55,44 @@ static int input_gssapi_mic(int type, u_
static int input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh);
static int input_gssapi_errtok(int, u_int32_t, struct ssh *);
+/*
+ * The 'gssapi_keyex' userauth mechanism.
+ */
+static int
+userauth_gsskeyex(struct ssh *ssh)
+{
+ Authctxt *authctxt = ssh->authctxt;
+ int authenticated = 0;
+ struct sshbuf *b = NULL;
+ gss_buffer_desc mic, gssbuf;
+ u_int len;
+
+ mic.value = packet_get_string(&len);
+ mic.length = len;
+
+ packet_check_eom();
+
+ if ((b = sshbuf_new()) == NULL)
+ fatal("%s: sshbuf_new failed", __func__);
+
+ ssh_gssapi_buildmic(b, authctxt->user, authctxt->service,
+ "gssapi-keyex");
+
+ gssbuf.value = sshbuf_mutable_ptr(b);
+ gssbuf.length = sshbuf_len(b);
+
+ /* gss_kex_context is NULL with privsep, so we can't check it here */
+ if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gss_kex_context,
+ &gssbuf, &mic))))
+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+ authctxt->pw));
+
+ 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)
@@ -260,7 +296,8 @@ input_gssapi_exchange_complete(int type,
if ((r = sshpkt_get_end(ssh)) != 0)
fatal("%s: %s", __func__, ssh_err(r));
- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+ authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user,
+ authctxt->pw));
if ((!use_privsep || mm_is_monitor()) &&
(displayname = ssh_gssapi_displayname()) != NULL)
@@ -313,7 +350,8 @@ input_gssapi_mic(int type, u_int32_t ple
gssbuf.length = sshbuf_len(b);
if (!GSS_ERROR(PRIVSEP(ssh_gssapi_checkmic(gssctxt, &gssbuf, &mic))))
- authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));
+ authenticated =
+ PRIVSEP(ssh_gssapi_userok(authctxt->user, authctxt->pw));
else
logit("GSSAPI MIC check failed");
@@ -335,6 +373,12 @@ input_gssapi_mic(int type, u_int32_t ple
return 0;
}
+Authmethod method_gsskeyex = {
+ "gssapi-keyex",
+ userauth_gsskeyex,
+ &options.gss_authentication
+};
+
Authmethod method_gssapi = {
"gssapi-with-mic",
userauth_gssapi,
diff -up openssh/auth.c.gsskex openssh/auth.c
--- openssh/auth.c.gsskex 2018-08-22 11:47:33.274216158 +0200
+++ openssh/auth.c 2018-08-22 11:47:33.308216432 +0200
@@ -395,6 +395,7 @@ auth_root_allowed(struct ssh *ssh, const
case PERMIT_NO_PASSWD:
if (strcmp(method, "publickey") == 0 ||
strcmp(method, "hostbased") == 0 ||
+ strcmp(method, "gssapi-keyex") == 0 ||
strcmp(method, "gssapi-with-mic") == 0)
return 1;
break;
diff -up openssh/clientloop.c.gsskex openssh/clientloop.c
--- openssh/clientloop.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/clientloop.c 2018-08-22 11:47:33.309216441 +0200
@@ -112,6 +112,10 @@
#include "ssherr.h"
#include "hostfile.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
/* import options */
extern Options options;
@@ -1357,9 +1361,18 @@ client_loop(struct ssh *ssh, int have_pt
break;
/* Do channel operations unless rekeying in progress. */
- if (!ssh_packet_is_rekeying(ssh))
+ if (!ssh_packet_is_rekeying(ssh)) {
channel_after_select(ssh, readset, writeset);
+#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. */
client_process_net_input(readset);
diff -up openssh/configure.ac.gsskex openssh/configure.ac
--- openssh/configure.ac.gsskex 2018-08-22 11:47:33.296216335 +0200
+++ openssh/configure.ac 2018-08-22 11:47:33.309216441 +0200
@@ -673,6 +673,30 @@ main() { if (NSVersionOfRunTimeLibrary("
[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 -up openssh/gss-genr.c.gsskex openssh/gss-genr.c
--- openssh/gss-genr.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/gss-genr.c 2018-08-22 13:18:47.444383602 +0200
@@ -35,18 +35,179 @@
#include <string.h>
#include <signal.h>
#include <unistd.h>
+#include <openssl/evp.h>
#include "xmalloc.h"
#include "ssherr.h"
#include "sshbuf.h"
#include "log.h"
#include "ssh2.h"
+#include "cipher.h"
+#include "sshkey.h"
+#include "kex.h"
#include "ssh-gss.h"
extern u_char *session_id2;
extern u_int session_id2_len;
+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() {
+ return (gss_enc2oid != NULL);
+}
+
+/*
+ * 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) {
+ gss_OID_set gss_supported;
+ 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));
+}
+
+char *
+ssh_gssapi_kex_mechs(gss_OID_set gss_supported, ssh_gssapi_check_fn *check,
+ const char *host, const char *client) {
+ struct sshbuf *buf;
+ size_t i;
+ int oidpos, enclen, r;
+ char *mechs, *encoded;
+ u_char digest[EVP_MAX_MD_SIZE];
+ char deroid[2];
+ const EVP_MD *evp_md = EVP_md5();
+ EVP_MD_CTX *md;
+
+ 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("%s: sshbuf_new failed", __func__);
+
+ md = EVP_MD_CTX_new();
+ oidpos = 0;
+ 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;
+
+ EVP_DigestInit(md, evp_md);
+ EVP_DigestUpdate(md, deroid, 2);
+ EVP_DigestUpdate(md,
+ gss_supported->elements[i].elements,
+ gss_supported->elements[i].length);
+ EVP_DigestFinal(md, digest, NULL);
+
+ encoded = xmalloc(EVP_MD_size(evp_md) * 2);
+ enclen = __b64_ntop(digest, EVP_MD_size(evp_md),
+ encoded, EVP_MD_size(evp_md) * 2);
+
+ if (oidpos != 0)
+ if ((r = sshbuf_put_u8(buf, ',')) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ if ((r = sshbuf_put(buf, KEX_GSS_GEX_SHA1_ID,
+ sizeof(KEX_GSS_GEX_SHA1_ID) - 1)) != 0 ||
+ (r = sshbuf_put(buf, encoded, enclen)) != 0 ||
+ (r = sshbuf_put_u8(buf, ',')) != 0 ||
+ (r = sshbuf_put(buf, KEX_GSS_GRP1_SHA1_ID,
+ sizeof(KEX_GSS_GRP1_SHA1_ID) - 1)) != 0 ||
+ (r = sshbuf_put(buf, encoded, enclen)) != 0 ||
+ (r = sshbuf_put_u8(buf, ',')) != 0 ||
+ (r = sshbuf_put(buf, KEX_GSS_GRP14_SHA1_ID,
+ sizeof(KEX_GSS_GRP14_SHA1_ID) - 1)) != 0 ||
+ (r = sshbuf_put(buf, encoded, enclen)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ gss_enc2oid[oidpos].oid = &(gss_supported->elements[i]);
+ gss_enc2oid[oidpos].encoded = encoded;
+ oidpos++;
+ }
+ }
+ EVP_MD_CTX_free(md);
+ gss_enc2oid[oidpos].oid = NULL;
+ gss_enc2oid[oidpos].encoded = NULL;
+
+ if ((r = sshbuf_put_u8(buf, '\0')) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ mechs = xmalloc(sshbuf_len(buf));
+ sshbuf_get(buf, mechs, sshbuf_len(buf));
+ 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;
+
+ switch (kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GRP1_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GRP1_SHA1_ID) - 1;
+ break;
+ case KEX_GSS_GRP14_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GRP14_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GRP14_SHA1_ID) - 1;
+ break;
+ case KEX_GSS_GEX_SHA1:
+ if (strlen(name) < sizeof(KEX_GSS_GEX_SHA1_ID))
+ return GSS_C_NO_OID;
+ name += sizeof(KEX_GSS_GEX_SHA1_ID) - 1;
+ break;
+ default:
+ return GSS_C_NO_OID;
+ }
+
+ 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;
+}
+
/* sshbuf_get for gss_buffer_desc */
int
ssh_gssapi_get_buffer_desc(struct sshbuf *b, gss_buffer_desc *g)
@@ -218,7 +373,7 @@ 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);
@@ -248,8 +403,42 @@ 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);
@@ -257,6 +446,19 @@ 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)
@@ -273,11 +475,16 @@ 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 &&
@@ -287,6 +494,10 @@ 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);
@@ -296,10 +507,66 @@ 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 -up openssh/gss-serv.c.gsskex openssh/gss-serv.c
--- openssh/gss-serv.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/gss-serv.c 2018-08-22 11:47:33.310216448 +0200
@@ -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}, 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 +143,28 @@ ssh_gssapi_server_ctx(Gssctxt **ctx, gss
}
/* Unprivileged */
+char *
+ssh_gssapi_server_mechanisms() {
+ if (supported_oids == NULL)
+ ssh_gssapi_prepare_supported_oids();
+ return (ssh_gssapi_kex_mechs(supported_oids,
+ &ssh_gssapi_server_check_mech, NULL, NULL));
+}
+
+/* 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(PRIVSEP(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 +174,9 @@ 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 +302,48 @@ 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;
+ }
+
+ 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_buffer_desc ename;
+ 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 +358,13 @@ 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 +382,8 @@ 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 +394,20 @@ 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("%s: krb5_cc_resolve(): %.100s", __func__,
+ krb5_get_err_text(gssapi_client.store.data, problem));
+ } else if ((problem = krb5_cc_destroy(gssapi_client.store.data, ccache))) {
+ debug("%s: krb5_cc_resolve(): %.100s", __func__,
+ krb5_get_err_text(gssapi_client.store.data, problem));
+ } else {
+ krb5_free_context(gssapi_client.store.data);
+ gssapi_client.store.data = NULL;
+ }
}
}
@@ -356,7 +440,7 @@ ssh_gssapi_do_child(char ***envp, u_int
/* Privileged */
int
-ssh_gssapi_userok(char *user)
+ssh_gssapi_userok(char *user, struct passwd *pw)
{
OM_uint32 lmin;
@@ -366,9 +450,11 @@ ssh_gssapi_userok(char *user)
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 +468,89 @@ 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() {
+ int ok;
+ int ret;
+#ifdef USE_PAM
+ pam_handle_t *pamh = NULL;
+ struct pam_conv pamconv = {ssh_gssapi_simple_conv, NULL};
+ char *envstr;
+#endif
+
+ if (gssapi_client.store.envval == NULL &&
+ gssapi_client.store.envvar == NULL)
+ return;
+
+ ok = PRIVSEP(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
+ if (!use_privsep) {
+ debug("Not even going to try and do PAM with privsep disabled");
+ return;
+ }
+
+ 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 -up openssh/gss-serv-krb5.c.gsskex openssh/gss-serv-krb5.c
--- openssh/gss-serv-krb5.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/gss-serv-krb5.c 2018-08-22 11:47:33.311216457 +0200
@@ -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 +180,23 @@ 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);
+#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';
+ }
+#endif
#ifdef USE_PAM
if (options.use_pam)
@@ -193,9 +205,76 @@ 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 +282,8 @@ 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 -up openssh/kex.c.gsskex openssh/kex.c
--- openssh/kex.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/kex.c 2018-08-22 11:47:33.311216457 +0200
@@ -54,6 +54,10 @@
#include "sshbuf.h"
#include "digest.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+
/* prototype */
static int kex_choose_conf(struct ssh *);
static int kex_input_newkeys(int, u_int32_t, struct ssh *);
@@ -103,6 +107,11 @@ static const struct kexalg kexalgs[] = {
{ KEX_CURVE25519_SHA256, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
{ KEX_CURVE25519_SHA256_OLD, KEX_C25519_SHA256, 0, SSH_DIGEST_SHA256 },
#endif /* HAVE_EVP_SHA256 || !WITH_OPENSSL */
+#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 },
+#endif
{ NULL, -1, -1, -1},
};
@@ -136,6 +145,12 @@ kex_alg_by_name(const char *name)
for (k = kexalgs; k->name != NULL; k++) {
if (strcmp(k->name, name) == 0)
return k;
+#ifdef GSSAPI
+ if (strncmp(name, "gss-", 4) == 0) {
+ if (strncmp(k->name, name, strlen(k->name)) == 0)
+ return k;
+ }
+#endif
}
return NULL;
}
diff -up openssh/kexgssc.c.gsskex openssh/kexgssc.c
--- openssh/kexgssc.c.gsskex 2018-08-22 11:47:33.311216457 +0200
+++ openssh/kexgssc.c 2018-08-22 11:47:33.311216457 +0200
@@ -0,0 +1,341 @@
+/*
+ * 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"
+
+#ifdef GSSAPI
+
+#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 "ssh-gss.h"
+
+int
+kexgss_client(struct ssh *ssh) {
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ gss_buffer_desc recv_tok, gssbuf, msg_tok, *token_ptr;
+ Gssctxt *ctxt;
+ OM_uint32 maj_status, min_status, ret_flags;
+ u_int klen, kout, slen = 0, strlen;
+ DH *dh;
+ BIGNUM *dh_server_pub = NULL;
+ BIGNUM *shared_secret = NULL;
+ BIGNUM *p = NULL;
+ BIGNUM *g = NULL;
+ const BIGNUM *pub_key, *p1, *g1;
+ u_char *kbuf;
+ u_char *serverhostkey = NULL;
+ u_char *empty = "";
+ char *msg;
+ char *lang;
+ int type = 0;
+ int first = 1;
+ int nbits = 0, min = DH_GRP_MIN, max = DH_GRP_MAX;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+
+ /* Initialise our GSSAPI world */
+ ssh_gssapi_build_ctx(&ctxt);
+ if (ssh_gssapi_id_kex(ctxt, ssh->kex->name, ssh->kex->kex_type)
+ == GSS_C_NO_OID)
+ fatal("Couldn't identify host exchange");
+
+ if (ssh_gssapi_import_name(ctxt, ssh->kex->gss_host))
+ fatal("Couldn't import hostname");
+
+ if (ssh->kex->gss_client &&
+ ssh_gssapi_client_identity(ctxt, ssh->kex->gss_client))
+ fatal("Couldn't acquire client credentials");
+
+ switch (ssh->kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ dh = dh_new_group1();
+ break;
+ case KEX_GSS_GRP14_SHA1:
+ dh = dh_new_group14();
+ break;
+ case KEX_GSS_GEX_SHA1:
+ debug("Doing group exchange\n");
+ nbits = dh_estimate(ssh->kex->we_need * 8);
+ packet_start(SSH2_MSG_KEXGSS_GROUPREQ);
+ packet_put_int(min);
+ packet_put_int(nbits);
+ packet_put_int(max);
+
+ packet_send();
+
+ packet_read_expect(SSH2_MSG_KEXGSS_GROUP);
+
+ if ((p = BN_new()) == NULL)
+ fatal("BN_new() failed");
+ packet_get_bignum2(p);
+ if ((g = BN_new()) == NULL)
+ fatal("BN_new() failed");
+ packet_get_bignum2(g);
+ packet_check_eom();
+
+ if (BN_num_bits(p) < min || BN_num_bits(p) > max)
+ fatal("GSSGRP_GEX group out of range: %d !< %d !< %d",
+ min, BN_num_bits(p), max);
+
+ dh = dh_new_group(g, p);
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
+ }
+
+ /* Step 1 - e is pub_key */
+ dh_gen_key(dh, ssh->kex->we_need * 8);
+ DH_get0_key(dh, &pub_key, NULL);
+
+ /* This is f, we initialise it now to make life easier */
+ dh_server_pub = BN_new();
+ if (dh_server_pub == NULL)
+ fatal("dh_server_pub == NULL");
+
+ token_ptr = GSS_C_NO_BUFFER;
+
+ do {
+ debug("Calling gss_init_sec_context");
+
+ maj_status = ssh_gssapi_init_ctx(ctxt,
+ ssh->kex->gss_deleg_creds, token_ptr, &send_tok,
+ &ret_flags);
+
+ if (GSS_ERROR(maj_status)) {
+ if (send_tok.length != 0) {
+ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+ packet_put_string(send_tok.value,
+ send_tok.length);
+ }
+ fatal("gss_init_context failed");
+ }
+
+ /* If we've got an old receive buffer get rid of it */
+ if (token_ptr != GSS_C_NO_BUFFER)
+ free(recv_tok.value);
+
+ if (maj_status == 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 (first) {
+ packet_start(SSH2_MSG_KEXGSS_INIT);
+ packet_put_string(send_tok.value,
+ send_tok.length);
+ packet_put_bignum2((BIGNUM *)pub_key);
+ first = 0;
+ } else {
+ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+ packet_put_string(send_tok.value,
+ send_tok.length);
+ }
+ packet_send();
+ gss_release_buffer(&min_status, &send_tok);
+
+ /* If we've sent them data, they should reply */
+ do {
+ type = packet_read();
+ if (type == SSH2_MSG_KEXGSS_HOSTKEY) {
+ debug("Received KEXGSS_HOSTKEY");
+ if (serverhostkey)
+ fatal("Server host key received more than once");
+ serverhostkey =
+ packet_get_string(&slen);
+ }
+ } while (type == SSH2_MSG_KEXGSS_HOSTKEY);
+
+ switch (type) {
+ case SSH2_MSG_KEXGSS_CONTINUE:
+ debug("Received GSSAPI_CONTINUE");
+ if (maj_status == GSS_S_COMPLETE)
+ fatal("GSSAPI Continue received from server when complete");
+ recv_tok.value = packet_get_string(&strlen);
+ recv_tok.length = strlen;
+ break;
+ case SSH2_MSG_KEXGSS_COMPLETE:
+ debug("Received GSSAPI_COMPLETE");
+ packet_get_bignum2(dh_server_pub);
+ msg_tok.value = packet_get_string(&strlen);
+ msg_tok.length = strlen;
+
+ /* Is there a token included? */
+ if (packet_get_char()) {
+ recv_tok.value=
+ packet_get_string(&strlen);
+ recv_tok.length = strlen;
+ /* If we're already complete - protocol error */
+ if (maj_status == GSS_S_COMPLETE)
+ packet_disconnect("Protocol error: received token when complete");
+ } else {
+ /* No token included */
+ if (maj_status != GSS_S_COMPLETE)
+ packet_disconnect("Protocol error: did not receive final token");
+ }
+ break;
+ case SSH2_MSG_KEXGSS_ERROR:
+ debug("Received Error");
+ maj_status = packet_get_int();
+ min_status = packet_get_int();
+ msg = packet_get_string(NULL);
+ lang = packet_get_string(NULL);
+ fatal("GSSAPI Error: \n%.400s",msg);
+ default:
+ packet_disconnect("Protocol error: didn't expect packet type %d",
+ type);
+ }
+ token_ptr = &recv_tok;
+ } else {
+ /* No data, and not complete */
+ if (maj_status != GSS_S_COMPLETE)
+ fatal("Not complete, and no token output");
+ }
+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
+
+ /*
+ * We _must_ have received a COMPLETE message in reply from the
+ * server, which will have set dh_server_pub and msg_tok
+ */
+
+ if (type != SSH2_MSG_KEXGSS_COMPLETE)
+ fatal("Didn't receive a SSH2_MSG_KEXGSS_COMPLETE when I expected it");
+
+ /* Check f in range [1, p-1] */
+ if (!dh_pub_is_valid(dh, dh_server_pub))
+ packet_disconnect("bad server public DH value");
+
+ /* compute K=f^x mod p */
+ klen = DH_size(dh);
+ kbuf = xmalloc(klen);
+ kout = DH_compute_key(kbuf, dh_server_pub, dh);
+ if ((int)kout < 0)
+ fatal("DH_compute_key: failed");
+
+ shared_secret = BN_new();
+ if (shared_secret == NULL)
+ fatal("kexgss_client: BN_new failed");
+
+ if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
+ fatal("kexdh_client: BN_bin2bn failed");
+
+ memset(kbuf, 0, klen);
+ free(kbuf);
+
+ hashlen = sizeof(hash);
+ switch (ssh->kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ kex_dh_hash(ssh->kex->hash_alg, ssh->kex->client_version_string,
+ ssh->kex->server_version_string,
+ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
+ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
+ (serverhostkey ? serverhostkey : empty), slen,
+ pub_key, /* e */
+ dh_server_pub, /* f */
+ shared_secret, /* K */
+ hash, &hashlen
+ );
+ break;
+ case KEX_GSS_GEX_SHA1:
+ DH_get0_pqg(dh, &p1, NULL, &g1);
+ kexgex_hash(
+ ssh->kex->hash_alg,
+ ssh->kex->client_version_string,
+ ssh->kex->server_version_string,
+ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
+ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
+ (serverhostkey ? serverhostkey : empty), slen,
+ min, nbits, max,
+ p, g,
+ pub_key,
+ dh_server_pub,
+ shared_secret,
+ hash, &hashlen
+ );
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
+ }
+
+ gssbuf.value = hash;
+ gssbuf.length = hashlen;
+
+ /* Verify that the hash matches the MIC we just got. */
+ if (GSS_ERROR(ssh_gssapi_checkmic(ctxt, &gssbuf, &msg_tok)))
+ packet_disconnect("Hash's MIC didn't verify");
+
+ free(msg_tok.value);
+
+ DH_free(dh);
+ if (serverhostkey)
+ free(serverhostkey);
+ BN_clear_free(dh_server_pub);
+
+ /* save session id */
+ if (ssh->kex->session_id == NULL) {
+ ssh->kex->session_id_len = hashlen;
+ ssh->kex->session_id = xmalloc(ssh->kex->session_id_len);
+ memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len);
+ }
+
+ if (ssh->kex->gss_deleg_creds)
+ ssh_gssapi_credentials_updated(ctxt);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = ctxt;
+ else
+ ssh_gssapi_delete_ctx(&ctxt);
+
+ kex_derive_keys_bn(ssh, hash, hashlen, shared_secret);
+ BN_clear_free(shared_secret);
+ return kex_send_newkeys(ssh);
+}
+
+#endif /* GSSAPI */
diff -up openssh/kexgsss.c.gsskex openssh/kexgsss.c
--- openssh/kexgsss.c.gsskex 2018-08-22 11:47:33.311216457 +0200
+++ openssh/kexgsss.c 2018-08-22 11:47:33.311216457 +0200
@@ -0,0 +1,300 @@
+/*
+ * 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"
+
+#ifdef GSSAPI
+
+#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"
+
+extern ServerOptions options;
+
+int
+kexgss_server(struct ssh *ssh)
+{
+ OM_uint32 maj_status, min_status;
+
+ /*
+ * Some GSSAPI implementations use the input value of ret_flags (an
+ * output variable) as a means of triggering mechanism specific
+ * features. Initializing it to zero avoids inadvertently
+ * activating this non-standard behaviour.
+ */
+
+ OM_uint32 ret_flags = 0;
+ gss_buffer_desc gssbuf, recv_tok, msg_tok;
+ gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
+ Gssctxt *ctxt = NULL;
+ u_int slen, klen, kout;
+ u_char *kbuf;
+ DH *dh;
+ int min = -1, max = -1, nbits = -1;
+ int cmin = -1, cmax = -1; /* client proposal */
+ BIGNUM *shared_secret = NULL;
+ BIGNUM *dh_client_pub = NULL;
+ int type = 0;
+ gss_OID oid;
+ char *mechs;
+ u_char hash[SSH_DIGEST_MAX_LENGTH];
+ size_t hashlen;
+ const BIGNUM *p, *g, *pub_key;
+
+ /* 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())
+ if ((mechs = ssh_gssapi_server_mechanisms()))
+ free(mechs);
+
+ debug2("%s: Identifying %s", __func__, ssh->kex->name);
+ oid = ssh_gssapi_id_kex(NULL, ssh->kex->name, ssh->kex->kex_type);
+ if (oid == GSS_C_NO_OID)
+ fatal("Unknown gssapi mechanism");
+
+ debug2("%s: Acquiring credentials", __func__);
+
+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_server_ctx(&ctxt, oid))))
+ fatal("Unable to acquire credentials for the server");
+
+ switch (ssh->kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ dh = dh_new_group1();
+ break;
+ case KEX_GSS_GRP14_SHA1:
+ dh = dh_new_group14();
+ break;
+ case KEX_GSS_GEX_SHA1:
+ debug("Doing group exchange");
+ packet_read_expect(SSH2_MSG_KEXGSS_GROUPREQ);
+ /* store client proposal to provide valid signature */
+ cmin = packet_get_int();
+ nbits = packet_get_int();
+ cmax = packet_get_int();
+ min = MAX(DH_GRP_MIN, cmin);
+ max = MIN(DH_GRP_MAX, cmax);
+ packet_check_eom();
+ if (max < min || nbits < min || max < nbits)
+ fatal("GSS_GEX, bad parameters: %d !< %d !< %d",
+ min, nbits, max);
+ dh = PRIVSEP(choose_dh(min, nbits, max));
+ if (dh == NULL)
+ packet_disconnect("Protocol error: no matching group found");
+
+ DH_get0_pqg(dh, &p, NULL, &g);
+ packet_start(SSH2_MSG_KEXGSS_GROUP);
+ packet_put_bignum2((BIGNUM *)p);
+ packet_put_bignum2((BIGNUM *)g);
+ packet_send();
+
+ packet_write_wait();
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
+ }
+
+ dh_gen_key(dh, ssh->kex->we_need * 8);
+
+ do {
+ debug("Wait SSH2_MSG_GSSAPI_INIT");
+ type = packet_read();
+ switch(type) {
+ case SSH2_MSG_KEXGSS_INIT:
+ if (dh_client_pub != NULL)
+ fatal("Received KEXGSS_INIT after initialising");
+ recv_tok.value = packet_get_string(&slen);
+ recv_tok.length = slen;
+
+ if ((dh_client_pub = BN_new()) == NULL)
+ fatal("dh_client_pub == NULL");
+
+ packet_get_bignum2(dh_client_pub);
+
+ /* Send SSH_MSG_KEXGSS_HOSTKEY here, if we want */
+ break;
+ case SSH2_MSG_KEXGSS_CONTINUE:
+ recv_tok.value = packet_get_string(&slen);
+ recv_tok.length = slen;
+ break;
+ default:
+ packet_disconnect(
+ "Protocol error: didn't expect packet type %d",
+ type);
+ }
+
+ maj_status = PRIVSEP(ssh_gssapi_accept_ctx(ctxt, &recv_tok,
+ &send_tok, &ret_flags));
+
+ free(recv_tok.value);
+
+ if (maj_status != GSS_S_COMPLETE && send_tok.length == 0)
+ fatal("Zero length token output when incomplete");
+
+ if (dh_client_pub == NULL)
+ fatal("No client public key");
+
+ if (maj_status & GSS_S_CONTINUE_NEEDED) {
+ debug("Sending GSSAPI_CONTINUE");
+ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+ packet_put_string(send_tok.value, send_tok.length);
+ packet_send();
+ gss_release_buffer(&min_status, &send_tok);
+ }
+ } while (maj_status & GSS_S_CONTINUE_NEEDED);
+
+ if (GSS_ERROR(maj_status)) {
+ if (send_tok.length > 0) {
+ packet_start(SSH2_MSG_KEXGSS_CONTINUE);
+ packet_put_string(send_tok.value, send_tok.length);
+ packet_send();
+ }
+ 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 (!dh_pub_is_valid(dh, dh_client_pub))
+ packet_disconnect("bad client public DH value");
+
+ klen = DH_size(dh);
+ kbuf = xmalloc(klen);
+ kout = DH_compute_key(kbuf, dh_client_pub, dh);
+ if ((int)kout < 0)
+ fatal("DH_compute_key: failed");
+
+ shared_secret = BN_new();
+ if (shared_secret == NULL)
+ fatal("kexgss_server: BN_new failed");
+
+ if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
+ fatal("kexgss_server: BN_bin2bn failed");
+
+ memset(kbuf, 0, klen);
+ free(kbuf);
+
+ DH_get0_key(dh, &pub_key, NULL);
+ hashlen = sizeof(hash);
+ switch (ssh->kex->kex_type) {
+ case KEX_GSS_GRP1_SHA1:
+ case KEX_GSS_GRP14_SHA1:
+ kex_dh_hash(ssh->kex->hash_alg,
+ ssh->kex->client_version_string, ssh->kex->server_version_string,
+ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
+ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
+ NULL, 0, /* Change this if we start sending host keys */
+ dh_client_pub, pub_key, shared_secret,
+ hash, &hashlen
+ );
+ break;
+ case KEX_GSS_GEX_SHA1:
+ kexgex_hash(
+ ssh->kex->hash_alg,
+ ssh->kex->client_version_string, ssh->kex->server_version_string,
+ sshbuf_ptr(ssh->kex->peer), sshbuf_len(ssh->kex->peer),
+ sshbuf_ptr(ssh->kex->my), sshbuf_len(ssh->kex->my),
+ NULL, 0,
+ cmin, nbits, cmax,
+ p, g,
+ dh_client_pub,
+ pub_key,
+ shared_secret,
+ hash, &hashlen
+ );
+ break;
+ default:
+ fatal("%s: Unexpected KEX type %d", __func__, ssh->kex->kex_type);
+ }
+
+ BN_clear_free(dh_client_pub);
+
+ if (ssh->kex->session_id == NULL) {
+ ssh->kex->session_id_len = hashlen;
+ ssh->kex->session_id = xmalloc(ssh->kex->session_id_len);
+ memcpy(ssh->kex->session_id, hash, ssh->kex->session_id_len);
+ }
+
+ gssbuf.value = hash;
+ gssbuf.length = hashlen;
+
+ if (GSS_ERROR(PRIVSEP(ssh_gssapi_sign(ctxt,&gssbuf,&msg_tok))))
+ fatal("Couldn't get MIC");
+
+ packet_start(SSH2_MSG_KEXGSS_COMPLETE);
+ packet_put_bignum2(pub_key);
+ packet_put_string(msg_tok.value,msg_tok.length);
+
+ if (send_tok.length != 0) {
+ packet_put_char(1); /* true */
+ packet_put_string(send_tok.value, send_tok.length);
+ } else {
+ packet_put_char(0); /* false */
+ }
+ packet_send();
+
+ gss_release_buffer(&min_status, &send_tok);
+ gss_release_buffer(&min_status, &msg_tok);
+
+ if (gss_kex_context == NULL)
+ gss_kex_context = ctxt;
+ else
+ ssh_gssapi_delete_ctx(&ctxt);
+
+ DH_free(dh);
+
+ kex_derive_keys_bn(ssh, hash, hashlen, shared_secret);
+ BN_clear_free(shared_secret);
+ 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();
+ return 0;
+}
+#endif /* GSSAPI */
diff -up openssh/kex.h.gsskex openssh/kex.h
--- openssh/kex.h.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/kex.h 2018-08-22 11:47:33.311216457 +0200
@@ -100,6 +100,11 @@ enum kex_exchange {
KEX_DH_GEX_SHA256,
KEX_ECDH_SHA2,
KEX_C25519_SHA256,
+#ifdef GSSAPI
+ KEX_GSS_GRP1_SHA1,
+ KEX_GSS_GRP14_SHA1,
+ KEX_GSS_GEX_SHA1,
+#endif
KEX_MAX
};
@@ -148,6 +153,12 @@ struct kex {
u_int flags;
int hash_alg;
int ec_nid;
+#ifdef GSSAPI
+ int gss_deleg_creds;
+ int gss_trust_dns;
+ char *gss_host;
+ char *gss_client;
+#endif
char *client_version_string;
char *server_version_string;
char *failed_choice;
@@ -197,6 +208,10 @@ int kexecdh_client(struct ssh *);
int kexecdh_server(struct ssh *);
int kexc25519_client(struct ssh *);
int kexc25519_server(struct ssh *);
+#ifdef GSSAPI
+int kexgss_client(struct ssh *);
+int kexgss_server(struct ssh *);
+#endif
int kex_dh_hash(int, const char *, const char *,
const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
diff -up openssh/Makefile.in.gsskex openssh/Makefile.in
--- openssh/Makefile.in.gsskex 2018-08-22 11:47:33.312216465 +0200
+++ openssh/Makefile.in 2018-08-22 13:19:54.955928277 +0200
@@ -100,6 +100,7 @@ LIBSSH_OBJS=${LIBOPENSSH_OBJS} \
readpass.o ttymodes.o xmalloc.o addrmatch.o \
atomicio.o dispatch.o mac.o uuencode.o misc.o utf8.o \
monitor_fdpass.o rijndael.o ssh-dss.o ssh-ecdsa.o ssh-rsa.o dh.o \
+ kexgssc.o \
msg.o progressmeter.o dns.o entropy.o gss-genr.o umac.o umac128.o \
ssh-pkcs11.o smult_curve25519_ref.o \
poly1305.o chacha.o cipher-chachapoly.o \
@@ -121,7 +122,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passw
auth-bsdauth.o auth2-hostbased.o auth2-kbdint.o \
auth2-none.o auth2-passwd.o auth2-pubkey.o \
monitor.o monitor_wrap.o auth-krb5.o \
- auth2-gss.o gss-serv.o gss-serv-krb5.o \
+ auth2-gss.o gss-serv.o gss-serv-krb5.o kexgsss.o \
loginrec.o auth-pam.o auth-shadow.o auth-sia.o md5crypt.o \
sftp-server.o sftp-common.o \
sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
diff -up openssh/monitor.c.gsskex openssh/monitor.c
--- openssh/monitor.c.gsskex 2018-08-22 11:47:33.263216069 +0200
+++ openssh/monitor.c 2018-08-22 13:22:19.589095240 +0200
@@ -146,6 +146,8 @@ int mm_answer_gss_setup_ctx(int, struct
int mm_answer_gss_accept_ctx(int, struct sshbuf *);
int mm_answer_gss_userok(int, struct sshbuf *);
int mm_answer_gss_checkmic(int, struct sshbuf *);
+int mm_answer_gss_sign(int, struct sshbuf *);
+int mm_answer_gss_updatecreds(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
@@ -293,6 +302,10 @@ monitor_child_preauth(Authctxt *_authctx
/* 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) {
@@ -405,6 +418,10 @@ monitor_child_postauth(struct monitor *p
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);
@@ -1695,6 +1712,13 @@ monitor_apply_keystate(struct monitor *p
# endif
#endif /* WITH_OPENSSL */
kex->kex[KEX_C25519_SHA256] = kexc25519_server;
+#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_GEX_SHA1] = kexgss_server;
+ }
+#endif
kex->load_host_public_key=&get_hostkey_public_by_type;
kex->load_host_private_key=&get_hostkey_private_by_type;
kex->host_key_index=&get_hostkey_index;
@@ -1785,7 +1809,7 @@ mm_answer_gss_setup_ctx(int sock, struct
u_char *p;
int r;
- if (!options.gss_authentication)
+ if (!options.gss_authentication && !options.gss_keyex)
fatal("%s: GSSAPI authentication not enabled", __func__);
if ((r = sshbuf_get_string(m, &p, &len)) != 0)
@@ -1818,7 +1842,7 @@ mm_answer_gss_accept_ctx(int sock, struc
OM_uint32 flags = 0; /* GSI needs this */
int r;
- if (!options.gss_authentication)
+ if (!options.gss_authentication && !options.gss_keyex)
fatal("%s: GSSAPI authentication not enabled", __func__);
if ((r = ssh_gssapi_get_buffer_desc(m, &in)) != 0)
@@ -1839,6 +1863,7 @@ mm_answer_gss_accept_ctx(int sock, struc
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);
}
@@ -1850,7 +1875,7 @@ mm_answer_gss_checkmic(int sock, struct
OM_uint32 ret;
int r;
- if (!options.gss_authentication)
+ if (!options.gss_authentication && !options.gss_keyex)
fatal("%s: GSSAPI authentication not enabled", __func__);
if ((r = ssh_gssapi_get_buffer_desc(m, &gssbuf)) != 0 ||
@@ -1880,10 +1905,11 @@ mm_answer_gss_userok(int sock, struct ss
int r, authenticated;
const char *displayname;
- if (!options.gss_authentication)
+ if (!options.gss_authentication && !options.gss_keyex)
fatal("%s: GSSAPI authentication not enabled", __func__);
- authenticated = authctxt->valid && ssh_gssapi_userok(authctxt->user);
+ authenticated = authctxt->valid &&
+ ssh_gssapi_userok(authctxt->user, authctxt->pw);
sshbuf_reset(m);
if ((r = sshbuf_put_u32(m, authenticated)) != 0)
@@ -1900,5 +1926,74 @@ mm_answer_gss_userok(int sock, struct ss
/* Monitor loop will terminate if authenticated */
return (authenticated);
}
+
+int
+mm_answer_gss_sign(int socket, struct sshbuf *m)
+{
+ gss_buffer_desc data;
+ gss_buffer_desc hash = GSS_C_EMPTY_BUFFER;
+ OM_uint32 major, minor;
+ int r;
+
+ if (!options.gss_authentication && !options.gss_keyex)
+ fatal("In GSSAPI monitor when GSSAPI is disabled");
+
+ if ((r = sshbuf_get_string(m, (u_char **)&data.value, &data.length)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+ if (data.length != 20)
+ fatal("%s: data length incorrect: %d", __func__,
+ (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("%s: buffer error: %s", __func__, ssh_err(r));
+
+ 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(int socket, struct sshbuf *m) {
+ ssh_gssapi_ccache store;
+ int ok, r;
+
+ if ((r = sshbuf_get_cstring(m, &store.envvar, NULL)) != 0 ||
+ (r = sshbuf_get_cstring(m, &store.envval, NULL)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ ok = ssh_gssapi_update_creds(&store);
+
+ free(store.envvar);
+ free(store.envval);
+
+ sshbuf_reset(m);
+ if ((r = sshbuf_put_u32(m, ok)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ mm_request_send(socket, MONITOR_ANS_GSSUPCREDS, m);
+
+ return(0);
+}
+
#endif /* GSSAPI */
diff -up openssh/monitor.h.gsskex openssh/monitor.h
--- openssh/monitor.h.gsskex 2018-08-22 11:47:33.263216069 +0200
+++ openssh/monitor.h 2018-08-22 11:47:33.313216473 +0200
@@ -58,6 +58,8 @@ enum monitor_reqtype {
#ifdef WITH_SELINUX
MONITOR_REQ_AUTHROLE = 80,
#endif
+ MONITOR_REQ_GSSSIGN = 82, MONITOR_ANS_GSSSIGN = 83,
+ MONITOR_REQ_GSSUPCREDS = 84, MONITOR_ANS_GSSUPCREDS = 85,
MONITOR_REQ_PAM_START = 100,
MONITOR_REQ_PAM_ACCOUNT = 102, MONITOR_ANS_PAM_ACCOUNT = 103,
diff -up openssh/monitor_wrap.c.gsskex openssh/monitor_wrap.c
--- openssh/monitor_wrap.c.gsskex 2018-08-22 11:47:33.313216473 +0200
+++ openssh/monitor_wrap.c 2018-08-22 13:27:38.665669643 +0200
@@ -1004,7 +1004,7 @@ mm_ssh_gssapi_checkmic(Gssctxt *ctx, gss
}
int
-mm_ssh_gssapi_userok(char *user)
+mm_ssh_gssapi_userok(char *user, struct passwd *pw)
{
struct sshbuf *m;
int r, authenticated = 0;
@@ -1023,4 +1023,52 @@ mm_ssh_gssapi_userok(char *user)
debug3("%s: user %sauthenticated",__func__, 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("%s: sshbuf_new failed", __func__);
+ if ((r = sshbuf_put_string(m, data->value, data->length)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ 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 = sshbuf_get_string(m, (u_char **)&hash->value, &hash->length)) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ sshbuf_free(m);
+
+ return (major);
+}
+
+int
+mm_ssh_gssapi_update_creds(ssh_gssapi_ccache *store)
+{
+ struct sshbuf *m;
+ int ok, r;
+
+ if ((m = sshbuf_new()) == NULL)
+ fatal("%s: sshbuf_new failed", __func__);
+
+ if ((r = sshbuf_put_cstring(m, store->envvar ? store->envvar : "")) != 0 ||
+ (r = sshbuf_put_cstring(m, store->envval ? store->envval : "")) != 0)
+ fatal("%s: buffer error: %s", __func__, ssh_err(r));
+
+ 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("%s: buffer error: %s", __func__, ssh_err(r));
+
+ sshbuf_free(m);
+
+ return (ok);
+}
#endif /* GSSAPI */
diff -up openssh/monitor_wrap.h.gsskex openssh/monitor_wrap.h
--- openssh/monitor_wrap.h.gsskex 2018-08-22 11:47:33.263216069 +0200
+++ openssh/monitor_wrap.h 2018-08-22 11:47:33.313216473 +0200
@@ -63,8 +63,10 @@ int mm_sshkey_verify(const struct sshkey
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 *);
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 -up openssh/readconf.c.gsskex openssh/readconf.c
--- openssh/readconf.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/readconf.c 2018-08-22 13:28:17.487982869 +0200
@@ -161,6 +161,8 @@ typedef enum {
oClearAllForwardings, oNoHostAuthenticationForLocalhost,
oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
oAddressFamily, oGssAuthentication, oGssDelegateCreds,
+ oGssTrustDns, oGssKeyEx, oGssClientIdentity, oGssRenewalRekey,
+ oGssServerIdentity,
oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
oHashKnownHosts,
@@ -201,10 +203,19 @@ static struct {
/* Sometimes-unsupported options */
#if defined(GSSAPI)
{ "gssapiauthentication", oGssAuthentication },
+ { "gssapikeyexchange", oGssKeyEx },
{ "gssapidelegatecredentials", oGssDelegateCreds },
+ { "gssapitrustdns", oGssTrustDns },
+ { "gssapiclientidentity", oGssClientIdentity },
+ { "gssapiserveridentity", oGssServerIdentity },
+ { "gssapirenewalforcesrekey", oGssRenewalRekey },
# else
{ "gssapiauthentication", oUnsupported },
+ { "gssapikeyexchange", oUnsupported },
{ "gssapidelegatecredentials", oUnsupported },
+ { "gssapitrustdns", oUnsupported },
+ { "gssapiclientidentity", oUnsupported },
+ { "gssapirenewalforcesrekey", oUnsupported },
#endif
#ifdef ENABLE_PKCS11
{ "smartcarddevice", oPKCS11Provider },
@@ -973,10 +984,30 @@ 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 oBatchMode:
intptr = &options->batch_mode;
goto parse_flag;
@@ -1817,7 +1848,12 @@ initialize_options(Options * options)
options->pubkey_authentication = -1;
options->challenge_response_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->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->kbd_interactive_devices = NULL;
@@ -1962,8 +1998,14 @@ fill_default_options(Options * options)
options->challenge_response_authentication = 1;
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;
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
diff -up openssh/readconf.h.gsskex openssh/readconf.h
--- openssh/readconf.h.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/readconf.h 2018-08-22 11:47:33.314216481 +0200
@@ -40,7 +40,12 @@ typedef struct {
int challenge_response_authentication;
/* Try S/Key or TIS, authentication. */
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 */
int password_authentication; /* Try password
* authentication. */
int kbd_interactive_authentication; /* Try keyboard-interactive auth. */
diff -up openssh/regress/cert-hostkey.sh.gsskex openssh/regress/cert-hostkey.sh
--- openssh/regress/cert-hostkey.sh.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/regress/cert-hostkey.sh 2018-08-22 11:47:33.314216481 +0200
@@ -66,7 +66,7 @@ touch $OBJ/host_revoked_plain
touch $OBJ/host_revoked_cert
cat $OBJ/host_ca_key.pub $OBJ/host_ca_key2.pub > $OBJ/host_revoked_ca
-PLAIN_TYPES=`$SSH -Q key-plain | sed 's/^ssh-dss/ssh-dsa/g;s/^ssh-//'`
+PLAIN_TYPES=`$SSH -Q key-plain | grep -v null | sed 's/^ssh-dss/ssh-dsa/g;s/^ssh-//'`
if echo "$PLAIN_TYPES" | grep '^rsa$' >/dev/null 2>&1 ; then
PLAIN_TYPES="$PLAIN_TYPES rsa-sha2-256 rsa-sha2-512"
diff -up openssh/regress/cert-userkey.sh.gsskex openssh/regress/cert-userkey.sh
--- openssh/regress/cert-userkey.sh.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/regress/cert-userkey.sh 2018-08-22 11:47:33.314216481 +0200
@@ -7,7 +7,7 @@ rm -f $OBJ/authorized_keys_$USER $OBJ/us
cp $OBJ/sshd_proxy $OBJ/sshd_proxy_bak
cp $OBJ/ssh_proxy $OBJ/ssh_proxy_bak
-PLAIN_TYPES=`$SSH -Q key-plain | sed 's/^ssh-dss/ssh-dsa/;s/^ssh-//'`
+PLAIN_TYPES=`$SSH -Q key-plain | grep -v null | sed 's/^ssh-dss/ssh-dsa/;s/^ssh-//'`
EXTRA_TYPES=""
if echo "$PLAIN_TYPES" | grep '^rsa$' >/dev/null 2>&1 ; then
diff -up openssh/regress/kextype.sh.gsskex openssh/regress/kextype.sh
--- openssh/regress/kextype.sh.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/regress/kextype.sh 2018-08-22 11:47:33.315216489 +0200
@@ -14,6 +14,9 @@ echo "KexAlgorithms=$KEXOPT" >> $OBJ/ssh
tries="1 2 3 4"
for k in `${SSH} -Q kex`; do
+ if [ $k = "gss-gex-sha1-" -o $k = "gss-group1-sha1-" -o $k = "gss-group14-sha1-" ]; then
+ continue
+ fi
verbose "kex $k"
for i in $tries; do
${SSH} -F $OBJ/ssh_proxy -o KexAlgorithms=$k x true
diff -up openssh/regress/rekey.sh.gsskex openssh/regress/rekey.sh
--- openssh/regress/rekey.sh.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/regress/rekey.sh 2018-08-22 11:47:33.315216489 +0200
@@ -38,6 +38,9 @@ increase_datafile_size 300
opts=""
for i in `${SSH} -Q kex`; do
+ if [ $i = "gss-gex-sha1-" -o $i = "gss-group1-sha1-" -o $i = "gss-group14-sha1-" ]; then
+ continue
+ fi
opts="$opts KexAlgorithms=$i"
done
for i in `${SSH} -Q cipher`; do
@@ -56,6 +59,9 @@ done
if ${SSH} -Q cipher-auth | grep '^.*$' >/dev/null 2>&1 ; then
for c in `${SSH} -Q cipher-auth`; do
for kex in `${SSH} -Q kex`; do
+ if [ $kex = "gss-gex-sha1-" -o $kex = "gss-group1-sha1-" -o $kex = "gss-group14-sha1-" ]; then
+ continue
+ fi
verbose "client rekey $c $kex"
ssh_data_rekeying "KexAlgorithms=$kex" -oRekeyLimit=256k -oCiphers=$c
done
diff -up openssh/servconf.c.gsskex openssh/servconf.c
--- openssh/servconf.c.gsskex 2018-08-22 11:47:33.296216335 +0200
+++ openssh/servconf.c 2018-08-22 13:28:41.905179879 +0200
@@ -124,8 +124,10 @@ 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->password_authentication = -1;
options->kbd_interactive_authentication = -1;
options->challenge_response_authentication = -1;
@@ -334,10 +336,14 @@ 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;
if (options->password_authentication == -1)
options->password_authentication = 1;
if (options->kbd_interactive_authentication == -1)
@@ -484,7 +490,7 @@ typedef enum {
sHostKeyAlgorithms,
sClientAliveInterval, sClientAliveCountMax, sAuthorizedKeysFile,
sGssAuthentication, sGssCleanupCreds, sGssStrictAcceptor,
- sAcceptEnv, sSetEnv, sPermitTunnel,
+ sGssKeyEx, sGssStoreRekey, sAcceptEnv, sSetEnv, sPermitTunnel,
sMatch, sPermitOpen, sPermitListen, sForceCommand, sChrootDirectory,
sUsePrivilegeSeparation, sAllowAgentForwarding,
sHostCertificate,
@@ -559,11 +565,17 @@ static struct {
{ "gssapiauthentication", sGssAuthentication, SSHCFG_ALL },
{ "gssapicleanupcredentials", sGssCleanupCreds, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sGssStrictAcceptor, SSHCFG_GLOBAL },
+ { "gssapikeyexchange", sGssKeyEx, SSHCFG_GLOBAL },
+ { "gssapistorecredentialsonrekey", sGssStoreRekey, SSHCFG_GLOBAL },
#else
{ "gssapiauthentication", sUnsupported, SSHCFG_ALL },
{ "gssapicleanupcredentials", sUnsupported, SSHCFG_GLOBAL },
{ "gssapistrictacceptorcheck", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapikeyexchange", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapistorecredentialsonrekey", sUnsupported, SSHCFG_GLOBAL },
#endif
+ { "gssusesessionccache", sUnsupported, SSHCFG_GLOBAL },
+ { "gssapiusesessioncredcache", sUnsupported, SSHCFG_GLOBAL },
{ "passwordauthentication", sPasswordAuthentication, SSHCFG_ALL },
{ "kbdinteractiveauthentication", sKbdInteractiveAuthentication, SSHCFG_ALL },
{ "challengeresponseauthentication", sChallengeResponseAuthentication, SSHCFG_GLOBAL },
@@ -1463,6 +1475,10 @@ process_server_config_line(ServerOptions
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;
@@ -1471,6 +1487,10 @@ process_server_config_line(ServerOptions
intptr = &options->gss_strict_acceptor;
goto parse_flag;
+ case sGssStoreRekey:
+ intptr = &options->gss_store_rekey;
+ goto parse_flag;
+
case sPasswordAuthentication:
intptr = &options->password_authentication;
goto parse_flag;
@@ -2560,6 +2580,9 @@ 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);
#endif
dump_cfg_fmtint(sPasswordAuthentication, o->password_authentication);
dump_cfg_fmtint(sKbdInteractiveAuthentication,
diff -up openssh/servconf.h.gsskex openssh/servconf.h
--- openssh/servconf.h.gsskex 2018-08-22 11:47:33.296216335 +0200
+++ openssh/servconf.h 2018-08-22 11:47:33.316216497 +0200
@@ -124,8 +124,10 @@ 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;
int password_authentication; /* If true, permit password
* authentication. */
int kbd_interactive_authentication; /* If true, permit */
diff -up openssh/ssh_config.5.gsskex openssh/ssh_config.5
--- openssh/ssh_config.5.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/ssh_config.5 2018-08-22 11:47:33.316216497 +0200
@@ -718,10 +718,40 @@ 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 can delegate the renewed
+credentials to a session on the server.
+The default is
+.Dq no .
+.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 HashKnownHosts
Indicates that
.Xr ssh 1
diff -up openssh/ssh_config.gsskex openssh/ssh_config
--- openssh/ssh_config.gsskex 2018-08-22 11:47:33.289216279 +0200
+++ openssh/ssh_config 2018-08-22 11:47:33.316216497 +0200
@@ -24,6 +24,8 @@
# HostbasedAuthentication no
# GSSAPIAuthentication no
# GSSAPIDelegateCredentials no
+# GSSAPIKeyExchange no
+# GSSAPITrustDNS no
# BatchMode no
# CheckHostIP yes
# AddressFamily any
diff -up openssh/sshconnect2.c.gsskex openssh/sshconnect2.c
--- openssh/sshconnect2.c.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/sshconnect2.c 2018-08-22 13:33:01.674275795 +0200
@@ -82,6 +82,124 @@ extern char *client_version_string;
extern char *server_version_string;
extern Options options;
+/* XXX from auth.h -- refactoring move these useful functions away of client context*/
+
+/*
+ * 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?)
+ */
+
+static 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) < 0) {
+ debug("getpeername failed: %.100s", strerror(errno));
+ return strdup(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 strdup(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 strdup(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 strdup(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 strdup(ntop);
+ }
+ return strdup(name);
+}
+
+/*
+ * Return the canonical name of the host in the other side of the current
+ * connection. The host name is cached, so it is efficient to call this
+ * several times.
+ */
+
+const char *
+get_canonical_hostname(struct ssh *ssh, int use_dns)
+{
+ static char *dnsname;
+
+ if (!use_dns)
+ return ssh_remote_ipaddr(ssh);
+ else if (dnsname != NULL)
+ return dnsname;
+ else {
+ dnsname = remote_hostname(ssh);
+ return dnsname;
+ }
+}
+
+
+
/*
* SSH2 key exchange
*/
@@ -162,9 +280,36 @@ ssh_kex2(char *host, struct sockaddr *ho
struct kex *kex;
int r;
+#ifdef GSSAPI
+ char *orig = NULL, *gss = NULL;
+ char *gss_host = NULL;
+#endif
+
xxx_host = host;
xxx_hostaddr = hostaddr;
+#ifdef GSSAPI
+ if (options.gss_keyex) {
+ /* Add the GSSAPI mechanisms currently supported on this
+ * client to the key exchange algorithm proposal */
+ orig = options.kex_algorithms;
+
+ if (options.gss_server_identity)
+ gss_host = options.gss_server_identity;
+ else if (options.gss_trust_dns)
+ gss_host = (char *)get_canonical_hostname(active_state, 1);
+ else
+ gss_host = host;
+
+ gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
+ if (gss) {
+ debug("Offering GSSAPI proposal: %s", gss);
+ xasprintf(&options.kex_algorithms,
+ "%s,%s", gss, orig);
+ }
+ }
+#endif
+
if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
fatal("%s: kex_names_cat", __func__);
myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s);
@@ -194,6 +337,17 @@ ssh_kex2(char *host, struct sockaddr *ho
order_hostkeyalgs(host, hostaddr, port));
}
+#ifdef GSSAPI
+ /* If we've got GSSAPI algorithms, then we also support the
+ * 'null' hostkey, as a last resort */
+ if (options.gss_keyex && gss) {
+ orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
+ xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
+ "%s,null", orig);
+ free(gss);
+ }
+#endif
+
if (options.rekey_limit || options.rekey_interval)
packet_set_rekey_limits(options.rekey_limit,
options.rekey_interval);
@@ -214,11 +368,31 @@ ssh_kex2(char *host, struct sockaddr *ho
kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
# endif
#endif
+#ifdef GSSAPI
+ if (options.gss_keyex) {
+ kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
+ kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
+ kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
+ }
+#endif
kex->kex[KEX_C25519_SHA256] = kexc25519_client;
kex->client_version_string=client_version_string;
kex->server_version_string=server_version_string;
kex->verify_host_key=&verify_host_key_callback;
+#ifdef GSSAPI
+ if (options.gss_keyex) {
+ kex->gss_deleg_creds = options.gss_deleg_creds;
+ kex->gss_trust_dns = options.gss_trust_dns;
+ kex->gss_client = options.gss_client_identity;
+ if (options.gss_server_identity) {
+ kex->gss_host = options.gss_server_identity;
+ } else {
+ kex->gss_host = gss_host;
+ }
+ }
+#endif
+
ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done);
/* remove ext-info from the KEX proposals for rekeying */
@@ -314,6 +488,7 @@ int input_gssapi_token(int type, u_int32
int input_gssapi_hash(int type, u_int32_t, struct ssh *);
int input_gssapi_error(int, u_int32_t, struct ssh *);
int input_gssapi_errtok(int, u_int32_t, struct ssh *);
+int userauth_gsskeyex(Authctxt *authctxt);
#endif
void userauth(Authctxt *, char *);
@@ -330,6 +505,11 @@ static char *authmethods_get(void);
Authmethod authmethods[] = {
#ifdef GSSAPI
+ {"gssapi-keyex",
+ userauth_gsskeyex,
+ NULL,
+ &options.gss_authentication,
+ NULL},
{"gssapi-with-mic",
userauth_gssapi,
NULL,
@@ -657,19 +837,31 @@ userauth_gssapi(Authctxt *authctxt)
static u_int mech = 0;
OM_uint32 min;
int r, ok = 0;
+ const char *gss_host;
+
+ if (options.gss_server_identity)
+ gss_host = options.gss_server_identity;
+ else if (options.gss_trust_dns)
+ gss_host = get_canonical_hostname(active_state, 1);
+ else
+ gss_host = authctxt->host;
/* Try one GSSAPI method at a time, rather than sending them all at
* once. */
if (gss_supported == NULL)
- gss_indicate_mechs(&min, &gss_supported);
+ if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
+ gss_supported = NULL;
+ return 0;
+ }
/* Check to see if the mechanism is usable before we offer it */
while (mech < gss_supported->count && !ok) {
/* My DER encoding requires length<128 */
if (gss_supported->elements[mech].length < 128 &&
ssh_gssapi_check_mechanism(&gssctxt,
- &gss_supported->elements[mech], authctxt->host)) {
+ &gss_supported->elements[mech], gss_host,
+ options.gss_client_identity)) {
ok = 1; /* Mechanism works */
} else {
mech++;
@@ -906,6 +1098,51 @@ input_gssapi_error(int type, u_int32_t p
free(lang);
return r;
}
+
+int
+userauth_gsskeyex(Authctxt *authctxt)
+{
+ struct sshbuf *b = NULL;
+ gss_buffer_desc gssbuf;
+ gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
+ OM_uint32 ms;
+
+ 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("%s: sshbuf_new failed", __func__);
+
+ ssh_gssapi_buildmic(b, authctxt->server_user, authctxt->service,
+ "gssapi-keyex");
+
+ gssbuf.value = sshbuf_mutable_ptr(b);
+ gssbuf.length = sshbuf_len(b);
+
+ if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
+ sshbuf_free(b);
+ return (0);
+ }
+
+ packet_start(SSH2_MSG_USERAUTH_REQUEST);
+ packet_put_cstring(authctxt->server_user);
+ packet_put_cstring(authctxt->service);
+ packet_put_cstring(authctxt->method->name);
+ packet_put_string(mic.value, mic.length);
+ packet_send();
+
+ sshbuf_free(b);
+ gss_release_buffer(&ms, &mic);
+
+ return (1);
+}
+
#endif /* GSSAPI */
int
diff -up openssh/sshd.c.gsskex openssh/sshd.c
--- openssh/sshd.c.gsskex 2018-08-22 11:47:33.299216360 +0200
+++ openssh/sshd.c 2018-08-22 13:34:28.455975954 +0200
@@ -887,8 +887,9 @@ notify_hostkeys(struct ssh *ssh)
}
debug3("%s: sent %u hostkeys", __func__, nkeys);
if (nkeys == 0)
- fatal("%s: no hostkeys", __func__);
- packet_send();
+ debug3("%s: no hostkeys", __func__);
+ else
+ packet_send();
sshbuf_free(buf);
}
@@ -1841,7 +1842,8 @@ 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);
}
@@ -2321,6 +2323,48 @@ do_ssh2_kex(void)
myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = compat_pkalg_proposal(
list_hostkey_types());
+#ifdef GSSAPI
+ {
+ 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)
+ newstr = gss;
+ 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] = "null";
+
+ if (newstr)
+ myproposal[PROPOSAL_KEX_ALGS] = newstr;
+ else
+ fatal("No supported key exchange algorithms");
+ }
+#endif
+
/* start key exchange */
if ((r = kex_setup(active_state, myproposal)) != 0)
fatal("kex_setup: %s", ssh_err(r));
@@ -2338,6 +2382,13 @@ do_ssh2_kex(void)
# endif
#endif
kex->kex[KEX_C25519_SHA256] = kexc25519_server;
+#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_GEX_SHA1] = kexgss_server;
+ }
+#endif
kex->server = 1;
kex->client_version_string=client_version_string;
kex->server_version_string=server_version_string;
diff -up openssh/sshd_config.5.gsskex openssh/sshd_config.5
--- openssh/sshd_config.5.gsskex 2018-08-22 11:47:33.297216344 +0200
+++ openssh/sshd_config.5 2018-08-22 13:35:05.531275099 +0200
@@ -642,6 +642,11 @@ 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
+.Dq no .
.It Cm GSSAPIStrictAcceptorCheck
Determines whether to be strict about the identity of the GSSAPI acceptor
a client authenticates against.
@@ -656,6 +661,11 @@ 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 .
.It Cm HostbasedAcceptedKeyTypes
Specifies the key types that will be accepted for hostbased authentication
as a list of comma-separated patterns.
diff -up openssh/sshd_config.gsskex openssh/sshd_config
--- openssh/sshd_config.gsskex 2018-08-22 11:47:33.299216360 +0200
+++ openssh/sshd_config 2018-08-22 11:47:33.318216513 +0200
@@ -85,6 +85,8 @@ ChallengeResponseAuthentication no
# GSSAPI options
GSSAPIAuthentication yes
GSSAPICleanupCredentials no
+#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 -up openssh/ssh-gss.h.gsskex openssh/ssh-gss.h
--- openssh/ssh-gss.h.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/ssh-gss.h 2018-08-22 13:36:44.773075793 +0200
@@ -1,6 +1,6 @@
/* $OpenBSD: ssh-gss.h,v 1.14 2018/07/10 09:13:30 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
@@ -61,10 +61,22 @@
#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_GEX_SHA1_ID "gss-gex-sha1-"
+
typedef struct {
char *filename;
char *envvar;
char *envval;
+ struct passwd *owner;
void *data;
} ssh_gssapi_ccache;
@@ -72,8 +84,11 @@ 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 +99,7 @@ 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 +110,11 @@ 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 */
} 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);
@@ -123,17 +140,33 @@ 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 *);
-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 *);
+char *ssh_gssapi_kex_mechs(gss_OID_set, ssh_gssapi_check_fn *, 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 *);
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();
+
+int ssh_gssapi_update_creds(ssh_gssapi_ccache *store);
+
+void ssh_gssapi_rekey_creds(void);
#endif /* GSSAPI */
#endif /* _SSH_GSS_H */
diff -up openssh/sshkey.c.gsskex openssh/sshkey.c
--- openssh/sshkey.c.gsskex 2018-08-22 11:47:33.319216521 +0200
+++ openssh/sshkey.c 2018-08-22 13:37:18.979351804 +0200
@@ -140,6 +140,7 @@ static const struct keytype keytypes[] =
# endif /* OPENSSL_HAS_NISTP521 */
# endif /* OPENSSL_HAS_ECC */
#endif /* WITH_OPENSSL */
+ { "null", "null", NULL, KEY_NULL, 0, 0, 1 },
{ NULL, NULL, NULL, -1, -1, 0, 0 }
};
diff -up openssh/sshkey.h.gsskex openssh/sshkey.h
--- openssh/sshkey.h.gsskex 2018-08-20 07:57:29.000000000 +0200
+++ openssh/sshkey.h 2018-08-22 11:47:33.320216529 +0200
@@ -63,6 +63,7 @@ enum sshkey_types {
KEY_ED25519_CERT,
KEY_XMSS,
KEY_XMSS_CERT,
+ KEY_NULL,
KEY_UNSPEC
};
--- openssh/sshconnect2.c.orig 2017-01-04 19:47:10.000000000 +0100
+++ openssh/sshconnect2.c 2017-01-05 04:13:08.977425272 +0100
@@ -344,7 +344,6 @@
orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
"%s,null", orig);
- free(gss);
}
#endif
@@ -398,6 +397,16 @@
/* remove ext-info from the KEX proposals for rekeying */
myproposal[PROPOSAL_KEX_ALGS] =
compat_kex_proposal(options.kex_algorithms);
+#ifdef GSSAPI
+ /* 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
if ((r = kex_prop2buf(kex->my, myproposal)) != 0)
fatal("kex_prop2buf: %s", ssh_err(r));
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