From 32230e2e4d543e75e73da794cdaf58f83b6f45c3 Mon Sep 17 00:00:00 2001 From: Joseph Sutton Date: Wed, 16 Feb 2022 17:03:10 +1300 Subject: [PATCH 1/2] s4/dsdb/samldb: Check for empty values array This avoids potentially trying to access the first element of an empty array. BUG: https://bugzilla.samba.org/show_bug.cgi?id=15008 Signed-off-by: Joseph Sutton --- source4/dsdb/samdb/ldb_modules/samldb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/source4/dsdb/samdb/ldb_modules/samldb.c b/source4/dsdb/samdb/ldb_modules/samldb.c index 24971d521aa..116c3ec1f00 100644 --- a/source4/dsdb/samdb/ldb_modules/samldb.c +++ b/source4/dsdb/samdb/ldb_modules/samldb.c @@ -751,7 +751,7 @@ static int samldb_schema_add_handle_linkid(struct samldb_ctx *ac) return ret; } - if (el == NULL) { + if (el == NULL || el->num_values == 0) { return LDB_SUCCESS; } @@ -919,7 +919,7 @@ static int samldb_schema_add_handle_mapiid(struct samldb_ctx *ac) return ret; } - if (el == NULL) { + if (el == NULL || el->num_values == 0) { return LDB_SUCCESS; } -- 2.35.0 From 6cd3312f866cf788087c5198106357e1674b3a6f Mon Sep 17 00:00:00 2001 From: Joseph Sutton Date: Thu, 17 Feb 2022 11:11:53 +1300 Subject: [PATCH 2/2] s4/dsdb/util: Use correct value for loop count limit Currently, we can crash the server by sending a large number of values of a specific attribute (such as sAMAccountName) spread across a few message elements. If val_count is larger than the total number of elements, we get an access beyond the elements array. Similarly, we can include unrelated message elements prior to the message elements of the attribute in question, so that not all of the attribute's values are copied into the returned elements values array. This can cause the server to access uninitialised data, likely resulting in a crash or unexpected behaviour. BUG: https://bugzilla.samba.org/show_bug.cgi?id=15008 Signed-off-by: Joseph Sutton --- source4/dsdb/samdb/ldb_modules/util.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/source4/dsdb/samdb/ldb_modules/util.c b/source4/dsdb/samdb/ldb_modules/util.c index 405febf0b3d..14947746837 100644 --- a/source4/dsdb/samdb/ldb_modules/util.c +++ b/source4/dsdb/samdb/ldb_modules/util.c @@ -1546,7 +1546,7 @@ int dsdb_get_expected_new_values(TALLOC_CTX *mem_ctx, v = _el->values; - for (i = 0; i < val_count; i++) { + for (i = 0; i < msg->num_elements; i++) { if (ldb_attr_cmp(msg->elements[i].name, attr_name) == 0) { if ((operation == LDB_MODIFY) && (LDB_FLAG_MOD_TYPE(msg->elements[i].flags) -- 2.35.0