More patches related to CVE-2017-14491

Signed-off-by: Petr Menšík <pemensik@redhat.com>
This commit is contained in:
Petr Menšík 2017-10-03 13:53:42 +02:00
parent d528970d82
commit 35c602043d
3 changed files with 126 additions and 1 deletions

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@ -0,0 +1,44 @@
From a3303e196e5d304ec955c4d63afb923ade66c6e8 Mon Sep 17 00:00:00 2001
From: Simon Kelley <simon@thekelleys.org.uk>
Date: Thu, 7 Sep 2017 20:45:00 +0100
Subject: [PATCH] Don't return arcount=1 if EDNS0 RR won't fit in the packet.
Omitting the EDNS0 RR but setting arcount gives a malformed packet.
Also, don't accept UDP packet size less than 512 in recieved EDNS0.
---
src/edns0.c | 5 ++++-
src/forward.c | 2 ++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/src/edns0.c b/src/edns0.c
index 3fde17f..f5b798c 100644
--- a/src/edns0.c
+++ b/src/edns0.c
@@ -208,7 +208,10 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
free(buff);
p += rdlen;
}
- header->arcount = htons(ntohs(header->arcount) + 1);
+
+ /* Only bump arcount if RR is going to fit */
+ if (((ssize_t)optlen) <= (limit - (p + 4)))
+ header->arcount = htons(ntohs(header->arcount) + 1);
}
if (((ssize_t)optlen) > (limit - (p + 4)))
diff --git a/src/forward.c b/src/forward.c
index e3fa94b..942b02d 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -1412,6 +1412,8 @@ void receive_query(struct listener *listen, time_t now)
defaults to 512 */
if (udp_size > daemon->edns_pktsz)
udp_size = daemon->edns_pktsz;
+ else if (udp_size < PACKETSZ)
+ udp_size = PACKETSZ; /* Sanity check - can't reduce below default. RFC 6891 6.2.3 */
}
#ifdef HAVE_AUTH
--
2.9.5

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@ -0,0 +1,74 @@
From 9d2757b9714523b53ed487b57e740f1b5beb4e0b Mon Sep 17 00:00:00 2001
From: Doran Moppert <dmoppert@redhat.com>
Date: Tue, 26 Sep 2017 14:48:20 +0930
Subject: [PATCH] google patch hand-applied
---
src/edns0.c | 10 +++++-----
src/forward.c | 4 ++++
src/rfc1035.c | 6 ++++--
3 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/src/edns0.c b/src/edns0.c
index 9c6dbcb..268fbe7 100644
--- a/src/edns0.c
+++ b/src/edns0.c
@@ -212,11 +212,11 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
/* Copy back any options */
if (buff)
{
- if (p + rdlen > limit)
- {
- free(buff);
- return plen; /* Too big */
- }
+ if (p + rdlen > limit)
+ {
+ free(buff);
+ return plen; /* Too big */
+ }
memcpy(p, buff, rdlen);
free(buff);
p += rdlen;
diff --git a/src/forward.c b/src/forward.c
index d1962be..6b9c16e 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -1417,6 +1417,10 @@ void receive_query(struct listener *listen, time_t now)
udp_size = PACKETSZ; /* Sanity check - can't reduce below default. RFC 6891 6.2.3 */
}
+ // Make sure the udp size is not smaller than the incoming message so that we
+ // do not underflow
+ if (udp_size < n) udp_size = n;
+
#ifdef HAVE_AUTH
if (auth_dns)
{
diff --git a/src/rfc1035.c b/src/rfc1035.c
index 0bf3bcc..3513455 100644
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -1198,8 +1198,8 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
va_end(ap); /* clean up variable argument pointer */
j = p - sav - 2;
- /* this has already been checked against limit before */
- PUTSHORT(j, sav); /* Now, store real RDLength */
+ /* this has already been checked against limit before */
+ PUTSHORT(j, sav); /* Now, store real RDLength */
/* check for overflow of buffer */
if (limit && ((unsigned char *)limit - p) < 0)
@@ -1259,6 +1259,8 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
int nxdomain = 0, auth = 1, trunc = 0, sec_data = 1;
struct mx_srv_record *rec;
size_t len;
+ // Make sure we do not underflow here too.
+ if (qlen > (limit - ((char *)header))) return 0;
if (ntohs(header->ancount) != 0 ||
ntohs(header->nscount) != 0 ||
--
2.9.5

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@ -13,7 +13,7 @@
Name: dnsmasq Name: dnsmasq
Version: 2.77 Version: 2.77
Release: 8%{?extraversion:.%{extraversion}}%{?dist} Release: 9%{?extraversion:.%{extraversion}}%{?dist}
Summary: A lightweight DHCP/caching DNS server Summary: A lightweight DHCP/caching DNS server
Group: System Environment/Daemons Group: System Environment/Daemons
@ -32,6 +32,8 @@ Patch7: dnsmasq-2.77-CVE-2017-14495.patch
Patch8: dnsmasq-2.77-misc-cleanups.patch Patch8: dnsmasq-2.77-misc-cleanups.patch
Patch9: dnsmasq-2.77-CVE-2017-14491-2.patch Patch9: dnsmasq-2.77-CVE-2017-14491-2.patch
Patch10: dnsmasq-2.77-stdio.h.patch Patch10: dnsmasq-2.77-stdio.h.patch
Patch11: dnsmasq-2.77-arcount.patch
Patch12: dnsmasq-2.77-underflow.patch
BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n) BuildRoot: %{_tmppath}/%{name}-%{version}-%{release}-root-%(%{__id_u} -n)
@ -76,6 +78,8 @@ query/remove a DHCP server's leases.
%patch8 -p1 -b .misc-cleanups %patch8 -p1 -b .misc-cleanups
%patch9 -p1 -b .CVE-2017-14491-2 %patch9 -p1 -b .CVE-2017-14491-2
%patch10 -p1 -b .stdio.h %patch10 -p1 -b .stdio.h
%patch11 -p1 -b .arcount
%patch12 -p1 -b .underflow
# use /var/lib/dnsmasq instead of /var/lib/misc # 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 for file in dnsmasq.conf.example man/dnsmasq.8 man/es/dnsmasq.8 src/config.h; do
@ -162,6 +166,9 @@ rm -rf $RPM_BUILD_ROOT
%{_mandir}/man1/dhcp_* %{_mandir}/man1/dhcp_*
%changelog %changelog
* Tue Oct 03 2017 Petr Menšík <pemensik@redhat.com> - 2.77-9
- More patches related to CVE-2017-14491
* Mon Oct 02 2017 Petr Menšík <pemensik@redhat.com> - 2.77-8 * Mon Oct 02 2017 Petr Menšík <pemensik@redhat.com> - 2.77-8
- Security fix, CVE-2017-14491, DNS heap buffer overflow - Security fix, CVE-2017-14491, DNS heap buffer overflow
- Security fix, CVE-2017-14492, DHCPv6 RA heap overflow - Security fix, CVE-2017-14492, DHCPv6 RA heap overflow