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Security fix, CVE-2017-14491, DNS heap buffer overflow.

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Further fix to 0549c73b7ea6b22a3c49beb4d432f185a81efcbc
Handles case when RR name is not a pointer to the question,
only occurs for some auth-mode replies, therefore not
detected by fuzzing (?)

Signed-off-by: Petr Menšík <pemensik@redhat.com>
This commit is contained in:
Petr Menšík 2017-10-02 17:17:17 +02:00
parent dfac991c15
commit 6379c5b2d4
2 changed files with 70 additions and 0 deletions
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68
dnsmasq-2.77-CVE-2017-14491-2.patch Normal file
View File

@ -0,0 +1,68 @@
From 62cb936cb7ad5f219715515ae7d32dd281a5aa1f Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Tue, 26 Sep 2017 22:00:11 +0100
Subject: [PATCH 10/10] Security fix, CVE-2017-14491, DNS heap buffer overflow.
Further fix to 0549c73b7ea6b22a3c49beb4d432f185a81efcbc
Handles case when RR name is not a pointer to the question,
only occurs for some auth-mode replies, therefore not
detected by fuzzing (?)
---
src/rfc1035.c | 27 +++++++++++++++------------
1 file changed, 15 insertions(+), 12 deletions(-)
diff --git a/src/rfc1035.c b/src/rfc1035.c
index 27af023..56ab88b 100644
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -1086,32 +1086,35 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
va_start(ap, format); /* make ap point to 1st unamed argument */
- /* nameoffset (1 or 2) + type (2) + class (2) + ttl (4) + 0 (2) */
- CHECK_LIMIT(12);
-
if (nameoffset > 0)
{
+ CHECK_LIMIT(2);
PUTSHORT(nameoffset | 0xc000, p);
}
else
{
char *name = va_arg(ap, char *);
- if (name)
- p = do_rfc1035_name(p, name, limit);
- if (!p)
- {
- va_end(ap);
- goto truncated;
- }
-
+ if (name && !(p = do_rfc1035_name(p, name, limit)))
+ {
+ va_end(ap);
+ goto truncated;
+ }
+
if (nameoffset < 0)
{
+ CHECK_LIMIT(2);
PUTSHORT(-nameoffset | 0xc000, p);
}
else
- *p++ = 0;
+ {
+ CHECK_LIMIT(1);
+ *p++ = 0;
+ }
}
+ /* type (2) + class (2) + ttl (4) + rdlen (2) */
+ CHECK_LIMIT(10);
+
PUTSHORT(type, p);
PUTSHORT(class, p);
PUTLONG(ttl, p); /* TTL */
--
2.9.5

2
dnsmasq.spec
View File

@ -30,6 +30,7 @@ Patch5: dnsmasq-2.77-CVE-2017-14494.patch
Patch6: dnsmasq-2.77-CVE-2017-14496.patch
Patch7: dnsmasq-2.77-CVE-2017-14495.patch
Patch8: dnsmasq-2.77-misc-cleanups.patch
Patch9: dnsmasq-2.77-CVE-2017-14491-2.patch
BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -72,6 +73,7 @@ query/remove a DHCP server's leases.
%patch6 -p1 -b .CVE-2017-14496
%patch7 -p1 -b .CVE-2017-14495
%patch8 -p1 -b .misc-cleanups
%patch9 -p1 -b .CVE-2017-14491-2
# 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