On (12/04/16 12:07), Sumit Bose wrote:
On Tue, Apr 12, 2016 at 11:08:54AM +0200, Pavel Březina wrote:
> On 04/11/2016 05:58 PM, Lukas Slebodnik wrote:
> >On (11/04/16 15:01), Lukas Slebodnik wrote:
> >>ehlo,
> >>
> >>attached patch fix crash in #2980
> >>
> >>LS
> >
> >>From 422abe6e6263c3c907611a8611fa3f28d6e93ae0 Mon Sep 17 00:00:00 2001
> >>From: Lukas Slebodnik <lslebodn(a)redhat.com>
> >>Date: Mon, 11 Apr 2016 14:46:47 +0200
> >>Subject: [PATCH] IPA: Check RDN in ipa_add_ad_memberships_get_next
> >>
> >>LDB functions ldb_dn_get_component_val and ldb_dn_get_rdn_val
> >>validate dn before returning component value.
> >>It should be valid DN according to RFC4514.
> >>
> >>IPA/389ds might return problematic DN due to replication conflicts.
> >>e.g. "cn=System: Read Service
Delegations+nsuniqueid=b0736336-d06e11e5-8e8acabe-ce8d458d,cn=permissions,dc=example,dc=com"
> >>
> >>It's better to check return value of these LDb function rather than
> >>crash because of dereference of NULL pointer.
> >>
> >>Resolves:
> >>https://fedorahosted.org/sssd/ticket/2980
> >>---
> >>src/providers/ipa/ipa_subdomains_ext_groups.c | 8 +++++++-
> >>1 file changed, 7 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/src/providers/ipa/ipa_subdomains_ext_groups.c
b/src/providers/ipa/ipa_subdomains_ext_groups.c
> >>index
8e006663a31ff60b86cf6392c15ce711c52cf0fc..445538be8798d58aee5d0cabf53ce91d94467a26 100644
> >>--- a/src/providers/ipa/ipa_subdomains_ext_groups.c
> >>+++ b/src/providers/ipa/ipa_subdomains_ext_groups.c
> >>@@ -862,7 +862,13 @@ static void ipa_add_ad_memberships_get_next(struct
tevent_req *req)
> >> goto fail;
> >> }
> >>
> >>- val = ldb_dn_get_component_val(group_dn, 0);
> >>+ val = ldb_dn_get_rdn_val(group_dn);
> >>+ if (val == NULL) {
> >>+ DEBUG(SSSDBG_OP_FAILURE,
> >>+ "Invalid group DN [%s].\n",
state->groups[state->iter]);
> >>+ ret = EINVAL;
> >>+ goto fail;
> >>+ }
> >
> >Alternative solution is to validate group_dn with ldb_dn_validate
> >but it's already done in ldb_dn_get_component_val/ldb_dn_get_rdn_val
> >
>
> Did you consider using ipa_get_rdn instead? It would also check that dn has
> proper format.
I don't think this DN check is needed here, nevertheless like in
_ipa_get_rdn() the result of ldb_dn_get_rdn_val() should be checked for
+ if (val == NULL || val->data == NULL) {
Not a bad idea.
LS