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Backport KCM retrieval fixes

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Resolves: #1956403
This commit is contained in:
Robbie Harwood 2021-06-10 15:23:28 -04:00
parent aec30dcfcb
commit d223dacd67
6 changed files with 799 additions and 1 deletions
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359
Add-KCM_OP_GET_CRED_LIST-for-faster-iteration.patch Normal file
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@ -0,0 +1,359 @@
From baf60dbdeceb3cad35cad7d9930782f94b6c8221 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20B=C5=99ezina?= <pbrezina@redhat.com>
Date: Thu, 11 Feb 2021 15:33:10 +0100
Subject: [PATCH] Add KCM_OP_GET_CRED_LIST for faster iteration
For large caches, one IPC operation per credential dominates the cost
of iteration. Instead transfer the whole list of credentials to the
client in one IPC operation.
Add optional support for the new opcode to the test KCM server to
allow testing of the main and fallback code paths.
[ghudson@mit.edu: fixed memory leaks and potential memory errors;
adjusted code style and comments; rewrote commit message; added
kcmserver.py support and tests]
ticket: 8990 (new)
(cherry picked from commit 81bdb47d8ded390263d8ee48f71d5c312b4f1736)
(cherry picked from commit a0ee8b02e56c65e5dcd569caed0e151cef004ef4)
---
src/include/kcm.h | 12 ++-
src/lib/krb5/ccache/cc_kcm.c | 144 ++++++++++++++++++++++++++++++++---
src/tests/kcmserver.py | 28 ++++++-
src/tests/t_ccache.py | 10 ++-
4 files changed, 175 insertions(+), 19 deletions(-)
diff --git a/src/include/kcm.h b/src/include/kcm.h
index 5ea1447cd..e4140c3a0 100644
--- a/src/include/kcm.h
+++ b/src/include/kcm.h
@@ -51,9 +51,9 @@
*
* All replies begin with a 32-bit big-endian reply code.
*
- * Parameters are appended to the request or reply with no delimiters. Flags
- * and time offsets are stored as 32-bit big-endian integers. Names are
- * marshalled as zero-terminated strings. Principals and credentials are
+ * Parameters are appended to the request or reply with no delimiters. Flags,
+ * time offsets, and lengths are stored as 32-bit big-endian integers. Names
+ * are marshalled as zero-terminated strings. Principals and credentials are
* marshalled in the v4 FILE ccache format. UUIDs are 16 bytes. UUID lists
* are not delimited, so nothing can come after them.
*/
@@ -89,7 +89,11 @@ typedef enum kcm_opcode {
KCM_OP_HAVE_NTLM_CRED,
KCM_OP_DEL_NTLM_CRED,
KCM_OP_DO_NTLM_AUTH,
- KCM_OP_GET_NTLM_USER_LIST
+ KCM_OP_GET_NTLM_USER_LIST,
+
+ /* MIT extensions */
+ KCM_OP_MIT_EXTENSION_BASE = 13000,
+ KCM_OP_GET_CRED_LIST, /* (name) -> (count, count*{len, cred}) */
} kcm_opcode;
#endif /* KCM_H */
diff --git a/src/lib/krb5/ccache/cc_kcm.c b/src/lib/krb5/ccache/cc_kcm.c
index 9093f894d..772928e4d 100644
--- a/src/lib/krb5/ccache/cc_kcm.c
+++ b/src/lib/krb5/ccache/cc_kcm.c
@@ -61,6 +61,17 @@ struct uuid_list {
size_t pos;
};
+struct cred_list {
+ krb5_creds *creds;
+ size_t count;
+ size_t pos;
+};
+
+struct kcm_cursor {
+ struct uuid_list *uuids;
+ struct cred_list *creds;
+};
+
struct kcmio {
SOCKET fd;
#ifdef __APPLE__
@@ -489,6 +500,69 @@ free_uuid_list(struct uuid_list *uuids)
free(uuids);
}
+static void
+free_cred_list(struct cred_list *list)
+{
+ size_t i;
+
+ if (list == NULL)
+ return;
+
+ /* Creds are transferred to the caller as list->pos is incremented, so we
+ * can start freeing there. */
+ for (i = list->pos; i < list->count; i++)
+ krb5_free_cred_contents(NULL, &list->creds[i]);
+ free(list->creds);
+ free(list);
+}
+
+/* Fetch a cred list from req->reply. */
+static krb5_error_code
+kcmreq_get_cred_list(struct kcmreq *req, struct cred_list **creds_out)
+{
+ struct cred_list *list;
+ const unsigned char *data;
+ krb5_error_code ret = 0;
+ size_t count, len, i;
+
+ *creds_out = NULL;
+
+ /* Check a rough bound on the count to prevent very large allocations. */
+ count = k5_input_get_uint32_be(&req->reply);
+ if (count > req->reply.len / 4)
+ return KRB5_KCM_MALFORMED_REPLY;
+
+ list = malloc(sizeof(*list));
+ if (list == NULL)
+ return ENOMEM;
+
+ list->creds = NULL;
+ list->count = count;
+ list->pos = 0;
+ list->creds = k5calloc(count, sizeof(*list->creds), &ret);
+ if (list->creds == NULL) {
+ free(list);
+ return ret;
+ }
+
+ for (i = 0; i < count; i++) {
+ len = k5_input_get_uint32_be(&req->reply);
+ data = k5_input_get_bytes(&req->reply, len);
+ if (data == NULL)
+ break;
+ ret = k5_unmarshal_cred(data, len, 4, &list->creds[i]);
+ if (ret)
+ break;
+ }
+ if (i < count) {
+ free_cred_list(list);
+ return (ret == ENOMEM) ? ENOMEM : KRB5_KCM_MALFORMED_REPLY;
+ }
+
+ *creds_out = list;
+ return 0;
+}
+
static void
kcmreq_free(struct kcmreq *req)
{
@@ -753,33 +827,53 @@ kcm_start_seq_get(krb5_context context, krb5_ccache cache,
{
krb5_error_code ret;
struct kcmreq req = EMPTY_KCMREQ;
- struct uuid_list *uuids;
+ struct uuid_list *uuids = NULL;
+ struct cred_list *creds = NULL;
+ struct kcm_cursor *cursor;
*cursor_out = NULL;
get_kdc_offset(context, cache);
- kcmreq_init(&req, KCM_OP_GET_CRED_UUID_LIST, cache);
+ kcmreq_init(&req, KCM_OP_GET_CRED_LIST, cache);
ret = cache_call(context, cache, &req);
- if (ret)
+ if (ret == 0) {
+ /* GET_CRED_LIST is available. */
+ ret = kcmreq_get_cred_list(&req, &creds);
+ if (ret)
+ goto cleanup;
+ } else if (ret == KRB5_FCC_INTERNAL) {
+ /* Fall back to GET_CRED_UUID_LIST. */
+ kcmreq_free(&req);
+ kcmreq_init(&req, KCM_OP_GET_CRED_UUID_LIST, cache);
+ ret = cache_call(context, cache, &req);
+ if (ret)
+ goto cleanup;
+ ret = kcmreq_get_uuid_list(&req, &uuids);
+ if (ret)
+ goto cleanup;
+ } else {
goto cleanup;
- ret = kcmreq_get_uuid_list(&req, &uuids);
- if (ret)
+ }
+
+ cursor = k5alloc(sizeof(*cursor), &ret);
+ if (cursor == NULL)
goto cleanup;
- *cursor_out = (krb5_cc_cursor)uuids;
+ cursor->uuids = uuids;
+ cursor->creds = creds;
+ *cursor_out = (krb5_cc_cursor)cursor;
cleanup:
kcmreq_free(&req);
return ret;
}
-static krb5_error_code KRB5_CALLCONV
-kcm_next_cred(krb5_context context, krb5_ccache cache, krb5_cc_cursor *cursor,
- krb5_creds *cred_out)
+static krb5_error_code
+next_cred_by_uuid(krb5_context context, krb5_ccache cache,
+ struct uuid_list *uuids, krb5_creds *cred_out)
{
krb5_error_code ret;
struct kcmreq req;
- struct uuid_list *uuids = (struct uuid_list *)*cursor;
memset(cred_out, 0, sizeof(*cred_out));
@@ -797,11 +891,39 @@ kcm_next_cred(krb5_context context, krb5_ccache cache, krb5_cc_cursor *cursor,
return map_invalid(ret);
}
+static krb5_error_code KRB5_CALLCONV
+kcm_next_cred(krb5_context context, krb5_ccache cache, krb5_cc_cursor *cursor,
+ krb5_creds *cred_out)
+{
+ struct kcm_cursor *c = (struct kcm_cursor *)*cursor;
+ struct cred_list *list;
+
+ if (c->uuids != NULL)
+ return next_cred_by_uuid(context, cache, c->uuids, cred_out);
+
+ list = c->creds;
+ if (list->pos >= list->count)
+ return KRB5_CC_END;
+
+ /* Transfer memory ownership of one cred to the caller. */
+ *cred_out = list->creds[list->pos];
+ memset(&list->creds[list->pos], 0, sizeof(*list->creds));
+ list->pos++;
+
+ return 0;
+}
+
static krb5_error_code KRB5_CALLCONV
kcm_end_seq_get(krb5_context context, krb5_ccache cache,
krb5_cc_cursor *cursor)
{
- free_uuid_list((struct uuid_list *)*cursor);
+ struct kcm_cursor *c = *cursor;
+
+ if (c == NULL)
+ return 0;
+ free_uuid_list(c->uuids);
+ free_cred_list(c->creds);
+ free(c);
*cursor = NULL;
return 0;
}
diff --git a/src/tests/kcmserver.py b/src/tests/kcmserver.py
index 57432e5a7..8c5e66ff1 100644
--- a/src/tests/kcmserver.py
+++ b/src/tests/kcmserver.py
@@ -23,6 +23,7 @@
# traceback.print_exception(etype, value, tb, file=f)
# sys.excepthook = ehook
+import optparse
import select
import socket
import struct
@@ -49,12 +50,14 @@ class KCMOpcodes(object):
SET_DEFAULT_CACHE = 21
GET_KDC_OFFSET = 22
SET_KDC_OFFSET = 23
+ GET_CRED_LIST = 13001
class KRB5Errors(object):
KRB5_CC_END = -1765328242
KRB5_CC_NOSUPP = -1765328137
KRB5_FCC_NOFILE = -1765328189
+ KRB5_FCC_INTERNAL = -1765328188
def make_uuid():
@@ -183,6 +186,14 @@ def op_set_kdc_offset(argbytes):
return 0, b''
+def op_get_cred_list(argbytes):
+ name, rest = unmarshal_name(argbytes)
+ cache = get_cache(name)
+ creds = [cache.creds[u] for u in cache.cred_uuids]
+ return 0, (struct.pack('>L', len(creds)) +
+ b''.join(struct.pack('>L', len(c)) + c for c in creds))
+
+
ophandlers = {
KCMOpcodes.GEN_NEW : op_gen_new,
KCMOpcodes.INITIALIZE : op_initialize,
@@ -197,7 +208,8 @@ ophandlers = {
KCMOpcodes.GET_DEFAULT_CACHE : op_get_default_cache,
KCMOpcodes.SET_DEFAULT_CACHE : op_set_default_cache,
KCMOpcodes.GET_KDC_OFFSET : op_get_kdc_offset,
- KCMOpcodes.SET_KDC_OFFSET : op_set_kdc_offset
+ KCMOpcodes.SET_KDC_OFFSET : op_set_kdc_offset,
+ KCMOpcodes.GET_CRED_LIST : op_get_cred_list
}
# Read and respond to a request from the socket s.
@@ -215,7 +227,11 @@ def service_request(s):
majver, minver, op = struct.unpack('>BBH', req[:4])
argbytes = req[4:]
- code, payload = ophandlers[op](argbytes)
+
+ if op in ophandlers:
+ code, payload = ophandlers[op](argbytes)
+ else:
+ code, payload = KRB5Errors.KRB5_FCC_INTERNAL, b''
# The KCM response is the code (4 bytes) and the response payload.
# The Heimdal IPC response is the length of the KCM response (4
@@ -226,9 +242,15 @@ def service_request(s):
s.sendall(hipc_response)
return True
+parser = optparse.OptionParser()
+parser.add_option('-c', '--credlist', action='store_true', dest='credlist',
+ default=False, help='Support KCM_OP_GET_CRED_LIST')
+(options, args) = parser.parse_args()
+if not options.credlist:
+ del ophandlers[KCMOpcodes.GET_CRED_LIST]
server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
-server.bind(sys.argv[1])
+server.bind(args[0])
server.listen(5)
select_input = [server,]
sys.stderr.write('starting...\n')
diff --git a/src/tests/t_ccache.py b/src/tests/t_ccache.py
index 66804afa5..90040fb7b 100755
--- a/src/tests/t_ccache.py
+++ b/src/tests/t_ccache.py
@@ -125,10 +125,18 @@ def collection_test(realm, ccname):
collection_test(realm, 'DIR:' + os.path.join(realm.testdir, 'cc'))
+
+# Test KCM without and with GET_CRED_LIST support.
kcmserver_path = os.path.join(srctop, 'tests', 'kcmserver.py')
-realm.start_server([sys.executable, kcmserver_path, kcm_socket_path],
+kcmd = realm.start_server([sys.executable, kcmserver_path, kcm_socket_path],
+ 'starting...')
+collection_test(realm, 'KCM:')
+stop_daemon(kcmd)
+os.remove(kcm_socket_path)
+realm.start_server([sys.executable, kcmserver_path, '-c', kcm_socket_path],
'starting...')
collection_test(realm, 'KCM:')
+
if test_keyring:
def cleanup_keyring(anchor, name):
out = realm.run(['keyctl', 'list', anchor])

104
Fix-KCM-flag-transmission-for-remove_cred.patch Normal file
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@ -0,0 +1,104 @@
From ddbb295dee2adcc6cec26944974420bba188f191 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Mon, 29 Mar 2021 14:32:56 -0400
Subject: [PATCH] Fix KCM flag transmission for remove_cred
MIT krb5 uses low bits for KRB5_TC flags, while Heimdal uses high bits
so that the same flag word can also hold KRB5_GC flags. Add a mapping
function and send the Heimdal flag values when performing a
remove_cred operation.
ticket: 8995
(cherry picked from commit 11a82cf424f9c905bb73680c64524f087090d4ef)
(cherry picked from commit 04f0de4420508161ce439f262f2761ff51a07ab0)
---
src/include/kcm.h | 19 +++++++++++++++++++
src/lib/krb5/ccache/cc_kcm.c | 36 +++++++++++++++++++++++++++++++++++-
2 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/src/include/kcm.h b/src/include/kcm.h
index e4140c3a0..9b66f1cbd 100644
--- a/src/include/kcm.h
+++ b/src/include/kcm.h
@@ -56,8 +56,27 @@
* are marshalled as zero-terminated strings. Principals and credentials are
* marshalled in the v4 FILE ccache format. UUIDs are 16 bytes. UUID lists
* are not delimited, so nothing can come after them.
+ *
+ * Flag words must use Heimdal flag values, which are not the same as MIT krb5
+ * values for KRB5_GC and KRB5_TC constants. The same flag word may contain
+ * both kinds of flags in Heimdal, but not in MIT krb5. Defines for the
+ * applicable Heimdal flag values are given below using KCM_GC and KCM_TC
+ * prefixes.
*/
+#define KCM_GC_CACHED (1U << 0)
+
+#define KCM_TC_DONT_MATCH_REALM (1U << 31)
+#define KCM_TC_MATCH_KEYTYPE (1U << 30)
+#define KCM_TC_MATCH_SRV_NAMEONLY (1U << 29)
+#define KCM_TC_MATCH_FLAGS_EXACT (1U << 28)
+#define KCM_TC_MATCH_FLAGS (1U << 27)
+#define KCM_TC_MATCH_TIMES_EXACT (1U << 26)
+#define KCM_TC_MATCH_TIMES (1U << 25)
+#define KCM_TC_MATCH_AUTHDATA (1U << 24)
+#define KCM_TC_MATCH_2ND_TKT (1U << 23)
+#define KCM_TC_MATCH_IS_SKEY (1U << 22)
+
/* Opcodes without comments are currently unused in the MIT client
* implementation. */
typedef enum kcm_opcode {
diff --git a/src/lib/krb5/ccache/cc_kcm.c b/src/lib/krb5/ccache/cc_kcm.c
index 772928e4d..1f81a2190 100644
--- a/src/lib/krb5/ccache/cc_kcm.c
+++ b/src/lib/krb5/ccache/cc_kcm.c
@@ -110,6 +110,40 @@ map_invalid(krb5_error_code code)
KRB5_KCM_MALFORMED_REPLY : code;
}
+/*
+ * Map an MIT krb5 KRB5_TC flag word to the equivalent Heimdal flag word. Note
+ * that there is no MIT krb5 equivalent for Heimdal's KRB5_TC_DONT_MATCH_REALM
+ * (which is like KRB5_TC_MATCH_SRV_NAMEONLY but also applies to the client
+ * principal) and no Heimdal equivalent for MIT krb5's KRB5_TC_SUPPORTED_KTYPES
+ * (which matches against enctypes from the krb5_context rather than the
+ * matching cred).
+ */
+static inline krb5_flags
+map_tcflags(krb5_flags mitflags)
+{
+ krb5_flags heimflags = 0;
+
+ if (mitflags & KRB5_TC_MATCH_TIMES)
+ heimflags |= KCM_TC_MATCH_TIMES;
+ if (mitflags & KRB5_TC_MATCH_IS_SKEY)
+ heimflags |= KCM_TC_MATCH_IS_SKEY;
+ if (mitflags & KRB5_TC_MATCH_FLAGS)
+ heimflags |= KCM_TC_MATCH_FLAGS;
+ if (mitflags & KRB5_TC_MATCH_TIMES_EXACT)
+ heimflags |= KCM_TC_MATCH_TIMES_EXACT;
+ if (mitflags & KRB5_TC_MATCH_FLAGS_EXACT)
+ heimflags |= KCM_TC_MATCH_FLAGS_EXACT;
+ if (mitflags & KRB5_TC_MATCH_AUTHDATA)
+ heimflags |= KCM_TC_MATCH_AUTHDATA;
+ if (mitflags & KRB5_TC_MATCH_SRV_NAMEONLY)
+ heimflags |= KCM_TC_MATCH_SRV_NAMEONLY;
+ if (mitflags & KRB5_TC_MATCH_2ND_TKT)
+ heimflags |= KCM_TC_MATCH_2ND_TKT;
+ if (mitflags & KRB5_TC_MATCH_KTYPE)
+ heimflags |= KCM_TC_MATCH_KEYTYPE;
+ return heimflags;
+}
+
/* Begin a request for the given opcode. If cache is non-null, supply the
* cache name as a request parameter. */
static void
@@ -936,7 +970,7 @@ kcm_remove_cred(krb5_context context, krb5_ccache cache, krb5_flags flags,
struct kcmreq req;
kcmreq_init(&req, KCM_OP_REMOVE_CRED, cache);
- k5_buf_add_uint32_be(&req.reqbuf, flags);
+ k5_buf_add_uint32_be(&req.reqbuf, map_tcflags(flags));
k5_marshal_mcred(&req.reqbuf, mcred);
ret = cache_call(context, cache, &req);
kcmreq_free(&req);

63
Fix-KCM-retrieval-support-for-sssd.patch Normal file
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@ -0,0 +1,63 @@
From 6a00fd149edd017ece894566771e2e9d4ba089f4 Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Tue, 11 May 2021 14:04:07 -0400
Subject: [PATCH] Fix KCM retrieval support for sssd
Commit 795ebba8c039be172ab93cd41105c73ffdba0fdb added a retrieval
handler using KCM_OP_RETRIEVE, falling back on the same error codes as
the previous KCM_OP_GET_CRED_LIST support. But sssd (as of 2.4)
returns KRB5_CC_NOSUPP instead of KRB5_CC_IO if it recognizes an
opcode but does not implement it. Add a helper function to recognize
all known unsupported-opcode error codes, and use it in kcm_retrieve()
and kcm_start_seq_get().
ticket: 8997
(cherry picked from commit da103e36e13f3c846bcddbe38dd518a21e5260a0)
(cherry picked from commit a5b2cff51808cd86fe8195e7ac074ecd25c3344d)
---
src/lib/krb5/ccache/cc_kcm.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/src/lib/krb5/ccache/cc_kcm.c b/src/lib/krb5/ccache/cc_kcm.c
index 23fcf13ea..18505cd3d 100644
--- a/src/lib/krb5/ccache/cc_kcm.c
+++ b/src/lib/krb5/ccache/cc_kcm.c
@@ -144,6 +144,20 @@ map_tcflags(krb5_flags mitflags)
return heimflags;
}
+/*
+ * Return true if code could indicate an unsupported operation. Heimdal's KCM
+ * returns KRB5_FCC_INTERNAL. sssd's KCM daemon (as of sssd 2.4) returns
+ * KRB5_CC_NO_SUPP if it recognizes the operation but does not implement it,
+ * and KRB5_CC_IO if it doesn't recognize the operation (which is unfortunate
+ * since it could also indicate a communication failure).
+ */
+static krb5_boolean
+unsupported_op_error(krb5_error_code code)
+{
+ return code == KRB5_FCC_INTERNAL || code == KRB5_CC_IO ||
+ code == KRB5_CC_NOSUPP;
+}
+
/* Begin a request for the given opcode. If cache is non-null, supply the
* cache name as a request parameter. */
static void
@@ -841,7 +855,7 @@ kcm_retrieve(krb5_context context, krb5_ccache cache, krb5_flags flags,
ret = cache_call(context, cache, &req);
/* Fall back to iteration if the server does not support retrieval. */
- if (ret == KRB5_FCC_INTERNAL || ret == KRB5_CC_IO) {
+ if (unsupported_op_error(ret)) {
ret = k5_cc_retrieve_cred_default(context, cache, flags, mcred,
cred_out);
goto cleanup;
@@ -922,7 +936,7 @@ kcm_start_seq_get(krb5_context context, krb5_ccache cache,
ret = kcmreq_get_cred_list(&req, &creds);
if (ret)
goto cleanup;
- } else if (ret == KRB5_FCC_INTERNAL || ret == KRB5_CC_IO) {
+ } else if (unsupported_op_error(ret)) {
/* Fall back to GET_CRED_UUID_LIST. */
kcmreq_free(&req);
kcmreq_init(&req, KCM_OP_GET_CRED_UUID_LIST, cache);

27
Make-KCM-iteration-fallback-work-with-sssd-kcm.patch Normal file
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@ -0,0 +1,27 @@
From f7702c5b11bdd186d03fed32568c9a252d049d44 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20B=C5=99ezina?= <pbrezina@redhat.com>
Date: Tue, 30 Mar 2021 14:35:28 +0200
Subject: [PATCH] Make KCM iteration fallback work with sssd-kcm
sssd-kcm returns KRB5_CC_IO if the operation code is not known.
ticket: 8990
(cherry picked from commit 06afae820a44c1dc96ad88a0b16c3e50bc938b2a)
(cherry picked from commit 2dbca7e14c945d6394e0e05f285a068dcd541295)
---
src/lib/krb5/ccache/cc_kcm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/lib/krb5/ccache/cc_kcm.c b/src/lib/krb5/ccache/cc_kcm.c
index 1f81a2190..46705f1da 100644
--- a/src/lib/krb5/ccache/cc_kcm.c
+++ b/src/lib/krb5/ccache/cc_kcm.c
@@ -876,7 +876,7 @@ kcm_start_seq_get(krb5_context context, krb5_ccache cache,
ret = kcmreq_get_cred_list(&req, &creds);
if (ret)
goto cleanup;
- } else if (ret == KRB5_FCC_INTERNAL) {
+ } else if (ret == KRB5_FCC_INTERNAL || ret == KRB5_CC_IO) {
/* Fall back to GET_CRED_UUID_LIST. */
kcmreq_free(&req);
kcmreq_init(&req, KCM_OP_GET_CRED_UUID_LIST, cache);

236
Use-KCM_OP_RETRIEVE-in-KCM-client.patch Normal file
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@ -0,0 +1,236 @@
From ac0a117096324fa73afae291ed467f2ea66e279b Mon Sep 17 00:00:00 2001
From: Greg Hudson <ghudson@mit.edu>
Date: Fri, 26 Mar 2021 23:38:54 -0400
Subject: [PATCH] Use KCM_OP_RETRIEVE in KCM client
In kcm_retrieve(), try KCM_OP_RETRIEVE. Fall back to iteration if the
server doesn't implement it, or if we can an answer incompatible with
KRB5_TC_SUPPORTED_KTYPES.
In kcmserver.py, implement partial decoding for creds and cred tags so
that we can do a basic principal name match.
ticket: 8997 (new)
(cherry picked from commit 795ebba8c039be172ab93cd41105c73ffdba0fdb)
(cherry picked from commit c56d4b87de0f30a38dc61d374ad225d02d581eb3)
---
src/include/kcm.h | 2 +-
src/lib/krb5/ccache/cc_kcm.c | 52 +++++++++++++++++++++++++++++++++---
src/tests/kcmserver.py | 44 +++++++++++++++++++++++++++---
src/tests/t_ccache.py | 11 +++++---
4 files changed, 99 insertions(+), 10 deletions(-)
diff --git a/src/include/kcm.h b/src/include/kcm.h
index 9b66f1cbd..85c20d345 100644
--- a/src/include/kcm.h
+++ b/src/include/kcm.h
@@ -87,7 +87,7 @@ typedef enum kcm_opcode {
KCM_OP_INITIALIZE, /* (name, princ) -> () */
KCM_OP_DESTROY, /* (name) -> () */
KCM_OP_STORE, /* (name, cred) -> () */
- KCM_OP_RETRIEVE,
+ KCM_OP_RETRIEVE, /* (name, flags, credtag) -> (cred) */
KCM_OP_GET_PRINCIPAL, /* (name) -> (princ) */
KCM_OP_GET_CRED_UUID_LIST, /* (name) -> (uuid, ...) */
KCM_OP_GET_CRED_BY_UUID, /* (name, uuid) -> (cred) */
diff --git a/src/lib/krb5/ccache/cc_kcm.c b/src/lib/krb5/ccache/cc_kcm.c
index 46705f1da..23fcf13ea 100644
--- a/src/lib/krb5/ccache/cc_kcm.c
+++ b/src/lib/krb5/ccache/cc_kcm.c
@@ -826,9 +826,55 @@ static krb5_error_code KRB5_CALLCONV
kcm_retrieve(krb5_context context, krb5_ccache cache, krb5_flags flags,
krb5_creds *mcred, krb5_creds *cred_out)
{
- /* There is a KCM opcode for retrieving creds, but Heimdal's client doesn't
- * use it. It causes the KCM daemon to actually make a TGS request. */
- return k5_cc_retrieve_cred_default(context, cache, flags, mcred, cred_out);
+ krb5_error_code ret;
+ struct kcmreq req = EMPTY_KCMREQ;
+ krb5_creds cred;
+ krb5_enctype *enctypes = NULL;
+
+ memset(&cred, 0, sizeof(cred));
+
+ /* Include KCM_GC_CACHED in flags to prevent Heimdal's sssd from making a
+ * TGS request itself. */
+ kcmreq_init(&req, KCM_OP_RETRIEVE, cache);
+ k5_buf_add_uint32_be(&req.reqbuf, map_tcflags(flags) | KCM_GC_CACHED);
+ k5_marshal_mcred(&req.reqbuf, mcred);
+ ret = cache_call(context, cache, &req);
+
+ /* Fall back to iteration if the server does not support retrieval. */
+ if (ret == KRB5_FCC_INTERNAL || ret == KRB5_CC_IO) {
+ ret = k5_cc_retrieve_cred_default(context, cache, flags, mcred,
+ cred_out);
+ goto cleanup;
+ }
+ if (ret)
+ goto cleanup;
+
+ ret = k5_unmarshal_cred(req.reply.ptr, req.reply.len, 4, &cred);
+ if (ret)
+ goto cleanup;
+
+ /* In rare cases we might retrieve a credential with a session key this
+ * context can't support, in which case we must retry using iteration. */
+ if (flags & KRB5_TC_SUPPORTED_KTYPES) {
+ ret = krb5_get_tgs_ktypes(context, cred.server, &enctypes);
+ if (ret)
+ goto cleanup;
+ if (!k5_etypes_contains(enctypes, cred.keyblock.enctype)) {
+ ret = k5_cc_retrieve_cred_default(context, cache, flags, mcred,
+ cred_out);
+ goto cleanup;
+ }
+ }
+
+ *cred_out = cred;
+ memset(&cred, 0, sizeof(cred));
+
+cleanup:
+ kcmreq_free(&req);
+ krb5_free_cred_contents(context, &cred);
+ free(enctypes);
+ /* Heimdal's KCM returns KRB5_CC_END if no cred is found. */
+ return (ret == KRB5_CC_END) ? KRB5_CC_NOTFOUND : map_invalid(ret);
}
static krb5_error_code KRB5_CALLCONV
diff --git a/src/tests/kcmserver.py b/src/tests/kcmserver.py
index 8c5e66ff1..25e6f2bbe 100644
--- a/src/tests/kcmserver.py
+++ b/src/tests/kcmserver.py
@@ -40,6 +40,7 @@ class KCMOpcodes(object):
INITIALIZE = 4
DESTROY = 5
STORE = 6
+ RETRIEVE = 7
GET_PRINCIPAL = 8
GET_CRED_UUID_LIST = 9
GET_CRED_BY_UUID = 10
@@ -54,6 +55,7 @@ class KCMOpcodes(object):
class KRB5Errors(object):
+ KRB5_CC_NOTFOUND = -1765328243
KRB5_CC_END = -1765328242
KRB5_CC_NOSUPP = -1765328137
KRB5_FCC_NOFILE = -1765328189
@@ -86,11 +88,29 @@ def get_cache(name):
return cache
+def unpack_data(argbytes):
+ dlen, = struct.unpack('>L', argbytes[:4])
+ return argbytes[4:dlen+4], argbytes[dlen+4:]
+
+
def unmarshal_name(argbytes):
offset = argbytes.find(b'\0')
return argbytes[0:offset], argbytes[offset+1:]
+def unmarshal_princ(argbytes):
+ # Ignore the type at argbytes[0:4].
+ ncomps, = struct.unpack('>L', argbytes[4:8])
+ realm, rest = unpack_data(argbytes[8:])
+ comps = []
+ for i in range(ncomps):
+ comp, rest = unpack_data(rest)
+ comps.append(comp)
+ # Asssume no quoting is needed.
+ princ = b'/'.join(comps) + b'@' + realm
+ return princ, rest
+
+
def op_gen_new(argbytes):
# Does not actually check for uniqueness.
global next_unique
@@ -126,6 +146,22 @@ def op_store(argbytes):
return 0, b''
+def op_retrieve(argbytes):
+ name, rest = unmarshal_name(argbytes)
+ # Ignore the flags at rest[0:4] and the header at rest[4:8].
+ # Assume there are client and server creds in the tag and match
+ # only against them.
+ cprinc, rest = unmarshal_princ(rest[8:])
+ sprinc, rest = unmarshal_princ(rest)
+ cache = get_cache(name)
+ for cred in (cache.creds[u] for u in cache.cred_uuids):
+ cred_cprinc, rest = unmarshal_princ(cred)
+ cred_sprinc, rest = unmarshal_princ(rest)
+ if cred_cprinc == cprinc and cred_sprinc == sprinc:
+ return 0, cred
+ return KRB5Errors.KRB5_CC_NOTFOUND, b''
+
+
def op_get_principal(argbytes):
name, rest = unmarshal_name(argbytes)
cache = get_cache(name)
@@ -199,6 +235,7 @@ ophandlers = {
KCMOpcodes.INITIALIZE : op_initialize,
KCMOpcodes.DESTROY : op_destroy,
KCMOpcodes.STORE : op_store,
+ KCMOpcodes.RETRIEVE : op_retrieve,
KCMOpcodes.GET_PRINCIPAL : op_get_principal,
KCMOpcodes.GET_CRED_UUID_LIST : op_get_cred_uuid_list,
KCMOpcodes.GET_CRED_BY_UUID : op_get_cred_by_uuid,
@@ -243,10 +280,11 @@ def service_request(s):
return True
parser = optparse.OptionParser()
-parser.add_option('-c', '--credlist', action='store_true', dest='credlist',
- default=False, help='Support KCM_OP_GET_CRED_LIST')
+parser.add_option('-f', '--fallback', action='store_true', dest='fallback',
+ default=False, help='Do not support RETRIEVE/GET_CRED_LIST')
(options, args) = parser.parse_args()
-if not options.credlist:
+if options.fallback:
+ del ophandlers[KCMOpcodes.RETRIEVE]
del ophandlers[KCMOpcodes.GET_CRED_LIST]
server = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
diff --git a/src/tests/t_ccache.py b/src/tests/t_ccache.py
index 90040fb7b..6ea9fb969 100755
--- a/src/tests/t_ccache.py
+++ b/src/tests/t_ccache.py
@@ -25,7 +25,7 @@ from k5test import *
kcm_socket_path = os.path.join(os.getcwd(), 'testdir', 'kcm')
conf = {'libdefaults': {'kcm_socket': kcm_socket_path,
'kcm_mach_service': '-'}}
-realm = K5Realm(create_host=False, krb5_conf=conf)
+realm = K5Realm(krb5_conf=conf)
keyctl = which('keyctl')
out = realm.run([klist, '-c', 'KEYRING:process:abcd'], expected_code=1)
@@ -71,6 +71,11 @@ def collection_test(realm, ccname):
realm.kinit('alice', password('alice'))
realm.run([klist], expected_msg='Default principal: alice@')
realm.run([klist, '-A', '-s'])
+ realm.run([kvno, realm.host_princ], expected_msg = 'kvno = 1')
+ realm.run([kvno, realm.host_princ], expected_msg = 'kvno = 1')
+ out = realm.run([klist])
+ if out.count(realm.host_princ) != 1:
+ fail('Wrong number of service tickets in cache')
realm.run([kdestroy])
output = realm.run([klist], expected_code=1)
if 'No credentials cache' not in output and 'not found' not in output:
@@ -126,14 +131,14 @@ def collection_test(realm, ccname):
collection_test(realm, 'DIR:' + os.path.join(realm.testdir, 'cc'))
-# Test KCM without and with GET_CRED_LIST support.
+# Test KCM with and without RETRIEVE and GET_CRED_LIST support.
kcmserver_path = os.path.join(srctop, 'tests', 'kcmserver.py')
kcmd = realm.start_server([sys.executable, kcmserver_path, kcm_socket_path],
'starting...')
collection_test(realm, 'KCM:')
stop_daemon(kcmd)
os.remove(kcm_socket_path)
-realm.start_server([sys.executable, kcmserver_path, '-c', kcm_socket_path],
+realm.start_server([sys.executable, kcmserver_path, '-f', kcm_socket_path],
'starting...')
collection_test(realm, 'KCM:')

11
krb5.spec
View File

@ -42,7 +42,7 @@
Summary: The Kerberos network authentication system
Name: krb5
Version: 1.19.1
Release: %{?zdpd}5%{?dist}
Release: %{?zdpd}6%{?dist}
# rharwood has trust path to signing key and verifies on check-in
Source0: https://web.mit.edu/kerberos/dist/krb5/%{version}/krb5-%{version}%{?dashpre}.tar.gz
@ -79,6 +79,11 @@ Patch14: Use-OpenSSL-s-SSKDF-in-PKINIT-when-available.patch
Patch15: Use-OpenSSL-s-KBKDF-and-KRB5KDF-for-deriving-long-te.patch
Patch16: Handle-OpenSSL-3-s-providers.patch
Patch17: Handle-SSL_read-changed-behavior-on-server-hangup.patch
Patch18: Add-KCM_OP_GET_CRED_LIST-for-faster-iteration.patch
Patch19: Fix-KCM-flag-transmission-for-remove_cred.patch
Patch20: Make-KCM-iteration-fallback-work-with-sssd-kcm.patch
Patch21: Use-KCM_OP_RETRIEVE-in-KCM-client.patch
Patch22: Fix-KCM-retrieval-support-for-sssd.patch
License: MIT
URL: https://web.mit.edu/kerberos/www/
@ -640,6 +645,10 @@ exit 0
%{_libdir}/libkadm5srv_mit.so.*
%changelog
* Thu Jun 10 2021 Robbie Harwood <rharwood@redhat.com> - 1.19.1-6
- Backport KCM retrieval fixes
- Resolves: #1956403
* Thu May 20 2021 Robbie Harwood <rharwood@redhat.com> - 1.19.1-5
- Fix DES3 mention in KDFs
- Resolves: #1955873