[SSSD] [PATCH] IPA: handle searches by SID in apply_subdomain_homedir

Jakub Hrozek jhrozek at redhat.com
Tue Aug 12 08:54:13 UTC 2014


Hi,

the attached patch fixes https://fedorahosted.org/sssd/ticket/2391

To reproduce, request a group by SID, like this:

$ python
    import pysss_nss_idmap
    pysss_nss_idmap.getnamebysid('S-1-5-21-1104576142-166023250-1132398744-513')
    {'S-1-5-21-1104576142-166023250-1132398744-513': {'type': 2, 'name': u'domain users at win.example.com'}}
-------------- next part --------------
>From 95ef335f17739c441bb6c9793a6b4d7c6185ca2b Mon Sep 17 00:00:00 2001
From: Jakub Hrozek <jhrozek at redhat.com>
Date: Tue, 12 Aug 2014 10:32:33 +0200
Subject: [PATCH] IPA: handle searches by SID in apply_subdomain_homedir

https://fedorahosted.org/sssd/ticket/2391

apply_subdomain_homedir() didn't handle the situation where an entity
that doesn't match was requested from the cache. For user and group
lookups this wasn't a problem because the negative match was caught
sooner.

But SID lookups can match either user or group. When a group SID was
requested, the preceding LDAP request matched the SID and stored the
group in the cache. Then apply_subdomain_homedir() only tried to search
user by SID, didn't find the entry and accessed a NULL pointer.

A simple reproducer is:
$ python
>>> import pysss_nss_idmap
>>> pysss_nss_idmap.getnamebysid(group_sid)

The group_sid can be anything, including Domain Users (XXX-513)
---
 src/providers/ipa/ipa_subdomains_id.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/src/providers/ipa/ipa_subdomains_id.c b/src/providers/ipa/ipa_subdomains_id.c
index 113bc6c06f82bc631b3efa92b87a1cadc7f22605..7857cd566f7585663d2e0fc94b1265132f4af739 100644
--- a/src/providers/ipa/ipa_subdomains_id.c
+++ b/src/providers/ipa/ipa_subdomains_id.c
@@ -516,18 +516,22 @@ apply_subdomain_homedir(TALLOC_CTX *mem_ctx, struct sss_domain_info *dom,
         goto done;
     }
 
-    if (ret != EOK && ret != ENOENT) {
-        DEBUG(SSSDBG_OP_FAILURE,
-              "Failed to make request to our cache: [%d]: [%s]\n",
-               ret, sss_strerror(ret));
-        goto done;
-    }
-
     if ((res && res->count == 0) || (msg && msg->num_elements == 0)) {
         ret = ENOENT;
         goto done;
     }
 
+    if (ret != EOK && ret != ENOENT) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "Failed to make request to our cache: [%d]: [%s]\n",
+               ret, sss_strerror(ret));
+        goto done;
+    } else if (ret == ENOENT) {
+        DEBUG(SSSDBG_TRACE_FUNC, "Cannot find [%s] with search type [%d]\n",
+              filter_value, filter_type);
+        goto done;
+    }
+
     if (res != NULL) {
         msg = res->msgs[0];
     }
-- 
1.9.3



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