1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
Patch-Source: https://src.fedoraproject.org/rpms/dnsmasq/blob/f36/f/dnsmasq-2.77-underflow.patch
--
From 77c7cabbeab1fbe1f7296f33762771f208586e59 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 | 3 +++
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/src/edns0.c b/src/edns0.c
index 7bd26b8..7f96414 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 3d638e4..e254e35 100644
--- a/src/forward.c
+++ b/src/forward.c
@@ -1558,6 +1558,10 @@ 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_CONNTRACK
#ifdef HAVE_AUTH
if (!auth_dns || local_auth)
diff --git a/src/rfc1035.c b/src/rfc1035.c
index 6fc4f26..66fa00c 100644
--- a/src/rfc1035.c
+++ b/src/rfc1035.c
@@ -1396,6 +1396,9 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
size_t len;
int rd_bit = (header->hb3 & HB3_RD);
+ // 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 (ntohs(header->ancount) != 0 ||
ntohs(header->nscount) != 0 ||
--
2.31.1
|
