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Security fix, CVE-2017-14495, OOM in DNS response

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creation.

    Fix out-of-memory Dos vulnerability. An attacker which can
    send malicious DNS queries to dnsmasq can trigger memory
    allocations in the add_pseudoheader function
    The allocated memory is never freed which leads to a DoS
    through memory exhaustion. dnsmasq is vulnerable only
    if one of the following option is specified:
    --add-mac, --add-cpe-id or --add-subnet.

Signed-off-by: Petr Menšík <pemensik@redhat.com>
This commit is contained in:
Petr Menšík 2017-09-26 18:00:01 +02:00
parent d75aef2c01
commit ce9aecdce0
2 changed files with 44 additions and 0 deletions
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41
dnsmasq-2.77-CVE-2017-14495.patch Normal file
View File

@ -0,0 +1,41 @@
From 51eadb692a5123b9838e5a68ecace3ac579a3a45 Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Mon, 25 Sep 2017 20:16:50 +0100
Subject: [PATCH 7/9] Security fix, CVE-2017-14495, OOM in DNS response
creation.
Fix out-of-memory Dos vulnerability. An attacker which can
send malicious DNS queries to dnsmasq can trigger memory
allocations in the add_pseudoheader function
The allocated memory is never freed which leads to a DoS
through memory exhaustion. dnsmasq is vulnerable only
if one of the following option is specified:
--add-mac, --add-cpe-id or --add-subnet.
---
src/edns0.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/src/edns0.c b/src/edns0.c
index 95b74ee..89b2692 100644
--- a/src/edns0.c
+++ b/src/edns0.c
@@ -192,9 +192,15 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
!(p = skip_section(p,
ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount),
header, plen)))
+ {
+ free(buff);
return plen;
+ }
if (p + 11 > limit)
- return plen; /* Too big */
+ {
+ free(buff);
+ return plen; /* Too big */
+ }
*p++ = 0; /* empty name */
PUTSHORT(T_OPT, p);
PUTSHORT(udp_sz, p); /* max packet length, 512 if not given in EDNS0 header */
--
2.9.5

3
dnsmasq.spec
View File

@ -28,6 +28,7 @@ Patch3: dnsmasq-2.77-CVE-2017-14492.patch
Patch4: dnsmasq-2.77-CVE-2017-14493.patch
Patch5: dnsmasq-2.77-CVE-2017-14494.patch
Patch6: dnsmasq-2.77-CVE-2017-14496.patch
Patch7: dnsmasq-2.77-CVE-2017-14495.patch
BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -68,6 +69,7 @@ query/remove a DHCP server's leases.
%patch4 -p1 -b .CVE-2017-14493
%patch5 -p1 -b .CVE-2017-14494
%patch6 -p1 -b .CVE-2017-14496
%patch7 -p1 -b .CVE-2017-14495
# use /var/lib/dnsmasq instead of /var/lib/misc
for file in dnsmasq.conf.example man/dnsmasq.8 man/es/dnsmasq.8 src/config.h; do
@ -160,6 +162,7 @@ rm -rf $RPM_BUILD_ROOT
- Security fix, CVE-2017-14493, DHCPv6 - Stack buffer overflow
- Security fix, CVE-2017-14494, Infoleak handling DHCPv6
- Security fix, CVE-2017-14496, Integer underflow in DNS response creation
- Security fix, CVE-2017-14495, OOM in DNS response creation
* Thu Sep 14 2017 Petr Menšík <pemensik@redhat.com> - 2.77-7
- Fix CVE-2017-13704