From ca7933730681bf3a42261fdf045dc1d929cbee48 Mon Sep 17 00:00:00 2001 From: Kevin Darbyshire-Bryant Date: Tue, 29 Aug 2017 14:29:18 +0100 Subject: [PATCH] dnsmasq: forward.c: fix CVE-2017-13704 Fix SIGSEGV in rfc1035.c answer_request() line 1228 where memset() is called with header & limit pointing at the same address and thus tries to clear memory from before the buffer begins. answer_request() is called with an invalid edns packet size provided by the client. Ensure the udp_size provided by the client is bounded by 512 and configured maximum as per RFC 6891 6.2.3 "Values lower than 512 MUST be treated as equal to 512" The client that exposed the problem provided a payload udp size of 0. Signed-off-by: Kevin Darbyshire-Bryant Acked-by: Hans Dedecker --- package/network/services/dnsmasq/Makefile | 2 +- .../patches/025-fix-CVE-2017-13704.patch | 37 +++++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) create mode 100644 package/network/services/dnsmasq/patches/025-fix-CVE-2017-13704.patch diff --git a/package/network/services/dnsmasq/Makefile b/package/network/services/dnsmasq/Makefile index d7f14f98ad..bd7f61010d 100644 --- a/package/network/services/dnsmasq/Makefile +++ b/package/network/services/dnsmasq/Makefile @@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk PKG_NAME:=dnsmasq PKG_VERSION:=2.77 -PKG_RELEASE:=9 +PKG_RELEASE:=10 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq/ diff --git a/package/network/services/dnsmasq/patches/025-fix-CVE-2017-13704.patch b/package/network/services/dnsmasq/patches/025-fix-CVE-2017-13704.patch new file mode 100644 index 0000000000..8848131dac --- /dev/null +++ b/package/network/services/dnsmasq/patches/025-fix-CVE-2017-13704.patch @@ -0,0 +1,37 @@ +From 38af9b1ac3242a4128e88069c495024caa565f0e Mon Sep 17 00:00:00 2001 +From: Kevin Darbyshire-Bryant +Date: Tue, 29 Aug 2017 12:35:40 +0100 +Subject: [PATCH] forward.c: fix CVE-2017-13704 + +Fix SIGSEGV in rfc1035.c answer_request() line 1228 where memset() +is called with header & limit pointing at the same address and thus +tries to clear memory from before the buffer begins. + +answer_request() is called with an invalid edns packet size provided by +the client. Ensure the udp_size provided by the client is bounded by +512 and configured maximum as per RFC 6891 6.2.3 "Values lower than 512 +MUST be treated as equal to 512" + +The client that exposed the problem provided a payload udp size of 0. + +Signed-off-by: Kevin Darbyshire-Bryant +--- + src/forward.c | 2 ++ + 1 file changed, 2 insertions(+) + +diff --git a/src/forward.c b/src/forward.c +index f22556a..62c5a5a 100644 +--- a/src/forward.c ++++ b/src/forward.c +@@ -1408,6 +1408,8 @@ void receive_query(struct listener *listen, time_t now) + defaults to 512 */ + if (udp_size > daemon->edns_pktsz) + udp_size = daemon->edns_pktsz; ++ if (udp_size < 512) ++ udp_size = 512; /* RFC 6891 6.2.3 */ + } + + #ifdef HAVE_AUTH +-- +2.7.4 + -- 2.25.1