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-rw-r--r--main/dnsmasq/CVE-2017-14496.patch66
1 files changed, 66 insertions, 0 deletions
diff --git a/main/dnsmasq/CVE-2017-14496.patch b/main/dnsmasq/CVE-2017-14496.patch
new file mode 100644
index 0000000000..85ac34202b
--- /dev/null
+++ b/main/dnsmasq/CVE-2017-14496.patch
@@ -0,0 +1,66 @@
+From 897c113fda0886a28a986cc6ba17bb93bd6cb1c7 Mon Sep 17 00:00:00 2001
+From: Simon Kelley <simon@thekelleys.org.uk>
+Date: Mon, 25 Sep 2017 20:11:58 +0100
+Subject: [PATCH] Security fix, CVE-2017-14496, Integer underflow in DNS
+ response creation.
+
+Fix DoS in DNS. Invalid boundary checks in the
+add_pseudoheader function allows a memcpy call with negative
+size An attacker which can send malicious DNS queries
+to dnsmasq can trigger a DoS remotely.
+dnsmasq is vulnerable only if one of the following option is
+specified: --add-mac, --add-cpe-id or --add-subnet.
+---
+ src/edns0.c | 13 ++++++++++++-
+ 1 file changed, 12 insertions(+), 1 deletion(-)
+
+diff --git a/src/edns0.c b/src/edns0.c
+index f5b798c..95b74ee 100644
+--- a/src/edns0.c
++++ b/src/edns0.c
+@@ -144,7 +144,7 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
+ GETSHORT(len, p);
+
+ /* malformed option, delete the whole OPT RR and start again. */
+- if (i + len > rdlen)
++ if (i + 4 + len > rdlen)
+ {
+ rdlen = 0;
+ is_last = 0;
+@@ -193,6 +193,8 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
+ ntohs(header->ancount) + ntohs(header->nscount) + ntohs(header->arcount),
+ header, plen)))
+ return plen;
++ if (p + 11 > limit)
++ return plen; /* Too big */
+ *p++ = 0; /* empty name */
+ PUTSHORT(T_OPT, p);
+ PUTSHORT(udp_sz, p); /* max packet length, 512 if not given in EDNS0 header */
+@@ -204,6 +206,11 @@ 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 */
++ }
+ memcpy(p, buff, rdlen);
+ free(buff);
+ p += rdlen;
+@@ -220,8 +227,12 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
+ /* Add new option */
+ if (optno != 0 && replace != 2)
+ {
++ if (p + 4 > limit)
++ return plen; /* Too big */
+ PUTSHORT(optno, p);
+ PUTSHORT(optlen, p);
++ if (p + optlen > limit)
++ return plen; /* Too big */
+ memcpy(p, opt, optlen);
+ p += optlen;
+ PUTSHORT(p - datap, lenp);
+--
+2.9.5
+