package/dnsmasq: fix CVE-2019-14834

A vulnerability was found in dnsmasq before version 2.81, where the
memory leak allows remote attackers to cause a denial of service
(memory consumption) via vectors involving DHCP response creation.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Fabrice Fontaine 2020-02-29 14:34:37 +01:00 committed by Yann E. MORIN
parent 4390b365a2
commit d0063f2ff1
2 changed files with 52 additions and 0 deletions

View File

@ -0,0 +1,49 @@
From 69bc94779c2f035a9fffdb5327a54c3aeca73ed5 Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Wed, 14 Aug 2019 20:44:50 +0100
Subject: [PATCH] Fix memory leak in helper.c
Thanks to Xu Mingjie <xumingjie1995@outlook.com> for spotting this.
[Retrieved from:
http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commit;h=69bc94779c2f035a9fffdb5327a54c3aeca73ed5]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
src/helper.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/src/helper.c b/src/helper.c
index 33ba120..c392eec 100644
--- a/src/helper.c
+++ b/src/helper.c
@@ -80,7 +80,8 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
pid_t pid;
int i, pipefd[2];
struct sigaction sigact;
-
+ unsigned char *alloc_buff = NULL;
+
/* create the pipe through which the main program sends us commands,
then fork our process. */
if (pipe(pipefd) == -1 || !fix_fd(pipefd[1]) || (pid = fork()) == -1)
@@ -186,11 +187,16 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
struct script_data data;
char *p, *action_str, *hostname = NULL, *domain = NULL;
unsigned char *buf = (unsigned char *)daemon->namebuff;
- unsigned char *end, *extradata, *alloc_buff = NULL;
+ unsigned char *end, *extradata;
int is6, err = 0;
int pipeout[2];
- free(alloc_buff);
+ /* Free rarely-allocated memory from previous iteration. */
+ if (alloc_buff)
+ {
+ free(alloc_buff);
+ alloc_buff = NULL;
+ }
/* we read zero bytes when pipe closed: this is our signal to exit */
if (!read_write(pipefd[0], (unsigned char *)&data, sizeof(data), 1))
--
1.7.10.4

View File

@ -15,6 +15,9 @@ DNSMASQ_DEPENDENCIES = host-pkgconf $(TARGET_NLS_DEPENDENCIES)
DNSMASQ_LICENSE = GPL-2.0 or GPL-3.0
DNSMASQ_LICENSE_FILES = COPYING COPYING-v3
# 0004-Fix-memory-leak-in-helper-c.patch
DNSMASQ_IGNORE_CVES += CVE-2019-14834
DNSMASQ_I18N = $(if $(BR2_SYSTEM_ENABLE_NLS),-i18n)
ifneq ($(BR2_PACKAGE_DNSMASQ_DHCP),y)