This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
[PATCH] Fix endless loop in nss_dns getnetbyname [BZ #17630]
- From: Florian Weimer <fweimer at redhat dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Cc: Roland McGrath <roland at hack dot frob dot com>
- Date: Mon, 15 Dec 2014 17:44:34 +0100
- Subject: [PATCH] Fix endless loop in nss_dns getnetbyname [BZ #17630]
- Authentication-results: sourceware.org; auth=none
The outer loop never advanced the alias pointer in case of a parse
error. I think this patch restores the original intent, but I'm not sure.
Tested on x86_64-redhat-linux-gnu.
I have requested CVE assignment on oss-security.
--
Florian Weimer / Red Hat Product Security
>From ac3dc70d931d9eb427085e67514a6dbef7142902 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Mon, 15 Dec 2014 17:41:13 +0100
Subject: [PATCH] Avoid infinite loop in nss_dns getnetbyname [BZ #17630]
2014-12-15 Florian Weimer <fweimer@redhat.com>
[BZ #17630]
* resolv/nss_dns/dns-network.c (getanswer_r): Iterate over alias
names.
diff --git a/NEWS b/NEWS
index a324c10..39f326e 100644
--- a/NEWS
+++ b/NEWS
@@ -13,8 +13,8 @@ Version 2.21
15884, 16469, 16617, 16619, 16657, 16740, 16857, 17192, 17266, 17344,
17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506, 17508,
17522, 17555, 17570, 17571, 17572, 17573, 17574, 17581, 17582, 17583,
- 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625, 17633, 17634,
- 17647, 17653, 17664, 17665, 17668, 17682.
+ 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625, 17630, 17633,
+ 17634, 17647, 17653, 17664, 17665, 17668, 17682.
* CVE-2104-7817 The wordexp function could ignore the WRDE_NOCMD flag
under certain input conditions resulting in the execution of a shell for
@@ -25,6 +25,9 @@ Version 2.21
* CVE-2012-3406 printf-style functions could run into a stack overflow when
processing format strings with a large number of format specifiers.
+* The nss_dns implementation of getnetbyname could run into an infinite loop
+ if the DNS response contained a PTR record of an unexpected format.
+
* The minimum GCC version that can be used to build this version of the GNU
C Library is GCC 4.6. Older GCC versions, and non-GNU compilers, can
still be used to compile programs using the GNU C Library.
diff --git a/resolv/nss_dns/dns-network.c b/resolv/nss_dns/dns-network.c
index 0a77c8b..08cf0a6 100644
--- a/resolv/nss_dns/dns-network.c
+++ b/resolv/nss_dns/dns-network.c
@@ -398,8 +398,8 @@ getanswer_r (const querybuf *answer, int anslen, struct netent *result,
case BYNAME:
{
- char **ap = result->n_aliases++;
- while (*ap != NULL)
+ char **ap;
+ for (ap = result->n_aliases; *ap != NULL; ++ap)
{
/* Check each alias name for being of the forms:
4.3.2.1.in-addr.arpa = net 1.2.3.4
--
2.1.0