dnsmasq/dnsmasq-2.77-underflow.patch

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From 0ef799244732871e043d848f2f845c797f5a0745 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 | 2 ++
3 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/src/edns0.c b/src/edns0.c
index af33877..ba6ff0c 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 3dd8633..64af66f 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -1577,6 +1577,10 @@ 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 6290f22..a943ecb 100644
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -1292,6 +1292,8 @@ 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;
/* never answer queries with RD unset, to avoid cache snooping. */
if (!(header->hb3 & HB3_RD) ||
--
2.14.4