s3:winbind:idmap_ldap: fix a crash bug in idmap_ldap_unixids_to_sids (#6387)

This fixes a crash bug hit when multiple mappings were found by
the ldap search. This crash was caused by an ldap asssertion
in ldap_next_entry because was set to NULL in each iteration.

The corresponding fix was applied to the idmap_ldap_sids_to_unixids()
by Jerry in 2007 (b066668b74768d9ed547f16bf7b6ba6aea5df20a).

This fixes the crash part of bug #6387.

There is a logic part, too:
The problem currently only occurs when multiple mappings are found
for one given unixid. Now winbindd does not crash any more but
it does not correctly handle this situation. It just returns the
last mapping from the ldap search results.
This needs fixing.

Michael
(cherry picked from commit e9010fa366746ec1ae948dbcf3493d446e23b14c)

Signed-off-by: Michael Adam <obnox@samba.org>
(cherry picked from commit 15652ee4259201a6d794c735d7e81631338f1050)

diff --git a/source/winbindd/idmap_ldap.c b/source/winbindd/idmap_ldap.c
index 53f63103b1d0185c3481e1b1a1edd0bb44cb2bb2..d4bf65bb58e7a32d357b50efb546d43130492984 100644 (file)
--- a/source/winbindd/idmap_ldap.c
+++ b/source/winbindd/idmap_ldap.c
@@ -893,6 +893,7 @@ static NTSTATUS idmap_ldap_unixids_to_sids(struct idmap_domain *dom,
        TALLOC_CTX *memctx;
        struct idmap_ldap_context *ctx;
        LDAPMessage *result = NULL;
+       LDAPMessage *entry = NULL;
        const char *uidNumber;
        const char *gidNumber;
        const char **attr_list;
@@ -988,7 +989,6 @@ again:
        }
 
        for (i = 0; i < count; i++) {
-               LDAPMessage *entry = NULL;
                char *sidstr = NULL;
                char *tmp = NULL;
                enum id_type type;