nixpkgs/pkgs/development/libraries/glibc/cve-2014-8121.patch
Vladimír Čunát 1fbbeff0c1 glibc: apply four security fixes from upstream
Fixes CVE-2014-8121, CVE-2015-1781 and two unnumbered problems (apparently).
All these commits should be contained in the 2.22 release,
but we don't want that yet due to unresolved locale incompatibilites.
2015-08-18 20:58:39 +02:00

231 lines
6.9 KiB
Diff

From 03d2730b44cc2236318fd978afa2651753666c55 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Wed, 29 Apr 2015 14:41:25 +0200
Subject: [PATCH] CVE-2014-8121: Do not close NSS files database during
iteration [BZ #18007]
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit
Robin Hack discovered Samba would enter an infinite loop processing
certain quota-related requests. We eventually tracked this down to a
glibc issue.
Running a (simplified) test case under strace shows that /etc/passwd
is continuously opened and closed:
…
open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
lseek(3, 0, SEEK_CUR) = 0
read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 2717
lseek(3, 2717, SEEK_SET) = 2717
close(3) = 0
open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
lseek(3, 0, SEEK_CUR) = 0
lseek(3, 0, SEEK_SET) = 0
read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 2717
lseek(3, 2717, SEEK_SET) = 2717
close(3) = 0
open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
lseek(3, 0, SEEK_CUR) = 0
…
The lookup function implementation in
nss/nss_files/files-XXX.c:DB_LOOKUP has code to prevent that. It is
supposed skip closing the input file if it was already open.
/* Reset file pointer to beginning or open file. */ \
status = internal_setent (keep_stream); \
\
if (status == NSS_STATUS_SUCCESS) \
{ \
/* Tell getent function that we have repositioned the file pointer. */ \
last_use = getby; \
\
while ((status = internal_getent (result, buffer, buflen, errnop \
H_ERRNO_ARG EXTRA_ARGS_VALUE)) \
== NSS_STATUS_SUCCESS) \
{ break_if_match } \
\
if (! keep_stream) \
internal_endent (); \
} \
keep_stream is initialized from the stayopen flag in internal_setent.
internal_setent is called from the set*ent implementation as:
status = internal_setent (stayopen);
However, for non-host database, this flag is always 0, per the
STAYOPEN magic in nss/getXXent_r.c.
Thus, the fix is this:
- status = internal_setent (stayopen);
+ status = internal_setent (1);
This is not a behavioral change even for the hosts database (where the
application can specify the stayopen flag) because with a call to
sethostent(0), the file handle is still not closed in the
implementation of gethostent.
---
ChangeLog | 8 ++++
NEWS | 12 +++--
nss/Makefile | 2 +-
nss/nss_files/files-XXX.c | 2 +-
nss/tst-nss-getpwent.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 136 insertions(+), 6 deletions(-)
create mode 100644 nss/tst-nss-getpwent.c
diff --git a/nss/Makefile b/nss/Makefile
index d75dad2..65ab7b5 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -47,7 +47,7 @@ install-bin := getent makedb
makedb-modules = xmalloc hash-string
extra-objs += $(makedb-modules:=.o)
-tests = test-netdb tst-nss-test1 test-digits-dots
+tests = test-netdb tst-nss-test1 test-digits-dots tst-nss-getpwent
xtests = bug-erange
# Specify rules for the nss_* modules. We have some services.
diff --git a/nss/nss_files/files-XXX.c b/nss/nss_files/files-XXX.c
index a7a45e5..a7ce5ea 100644
--- a/nss/nss_files/files-XXX.c
+++ b/nss/nss_files/files-XXX.c
@@ -134,7 +134,7 @@ CONCAT(_nss_files_set,ENTNAME) (int stayopen)
__libc_lock_lock (lock);
- status = internal_setent (stayopen);
+ status = internal_setent (1);
if (status == NSS_STATUS_SUCCESS && fgetpos (stream, &position) < 0)
{
diff --git a/nss/tst-nss-getpwent.c b/nss/tst-nss-getpwent.c
new file mode 100644
index 0000000..f2e8abc
--- /dev/null
+++ b/nss/tst-nss-getpwent.c
@@ -0,0 +1,118 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <pwd.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int
+do_test (void)
+{
+ /* Count the number of entries in the password database, and fetch
+ data from the first and last entries. */
+ size_t count = 0;
+ struct passwd * pw;
+ char *first_name = NULL;
+ uid_t first_uid = 0;
+ char *last_name = NULL;
+ uid_t last_uid = 0;
+ setpwent ();
+ while ((pw = getpwent ()) != NULL)
+ {
+ if (first_name == NULL)
+ {
+ first_name = strdup (pw->pw_name);
+ if (first_name == NULL)
+ {
+ printf ("strdup: %m\n");
+ return 1;
+ }
+ first_uid = pw->pw_uid;
+ }
+
+ free (last_name);
+ last_name = strdup (pw->pw_name);
+ if (last_name == NULL)
+ {
+ printf ("strdup: %m\n");
+ return 1;
+ }
+ last_uid = pw->pw_uid;
+ ++count;
+ }
+ endpwent ();
+
+ if (count == 0)
+ {
+ printf ("No entries in the password database.\n");
+ return 0;
+ }
+
+ /* Try again, this time interleaving with name-based and UID-based
+ lookup operations. The counts do not match if the interleaved
+ lookups affected the enumeration. */
+ size_t new_count = 0;
+ setpwent ();
+ while ((pw = getpwent ()) != NULL)
+ {
+ if (new_count == count)
+ {
+ printf ("Additional entry in the password database.\n");
+ return 1;
+ }
+ ++new_count;
+ struct passwd *pw2 = getpwnam (first_name);
+ if (pw2 == NULL)
+ {
+ printf ("getpwnam (%s) failed: %m\n", first_name);
+ return 1;
+ }
+ pw2 = getpwnam (last_name);
+ if (pw2 == NULL)
+ {
+ printf ("getpwnam (%s) failed: %m\n", last_name);
+ return 1;
+ }
+ pw2 = getpwuid (first_uid);
+ if (pw2 == NULL)
+ {
+ printf ("getpwuid (%llu) failed: %m\n",
+ (unsigned long long) first_uid);
+ return 1;
+ }
+ pw2 = getpwuid (last_uid);
+ if (pw2 == NULL)
+ {
+ printf ("getpwuid (%llu) failed: %m\n",
+ (unsigned long long) last_uid);
+ return 1;
+ }
+ }
+ endpwent ();
+ if (new_count < count)
+ {
+ printf ("Missing entry in the password database.\n");
+ return 1;
+ }
+
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"