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From d4f2e0b8d8f0b5daa0d468f62a0d5f1df58ac325 Mon Sep 17 00:00:00 2001
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From: Doran Moppert <dmoppert@redhat.com>
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Date: Tue, 26 Sep 2017 14:48:20 +0930
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Subject: [PATCH 9/9] google patch hand-applied
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---
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src/edns0.c | 10 +++++-----
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src/forward.c | 4 ++++
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src/rfc1035.c | 6 ++++--
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3 files changed, 13 insertions(+), 7 deletions(-)
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diff --git a/src/edns0.c b/src/edns0.c
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index 0552d38..bec4a36 100644
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--- a/src/edns0.c
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+++ b/src/edns0.c
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@@ -212,11 +212,11 @@ size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *l
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/* Copy back any options */
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if (buff)
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{
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- if (p + rdlen > limit)
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- {
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- free(buff);
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- return plen; /* Too big */
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- }
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+ if (p + rdlen > limit)
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+ {
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+ free(buff);
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+ return plen; /* Too big */
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+ }
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memcpy(p, buff, rdlen);
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free(buff);
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p += rdlen;
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diff --git a/src/forward.c b/src/forward.c
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index 0f8f462..a729c06 100644
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--- a/src/forward.c
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+++ b/src/forward.c
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@@ -1412,6 +1412,10 @@ void receive_query(struct listener *listen, time_t now)
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udp_size = PACKETSZ; /* Sanity check - can't reduce below default. RFC 6891 6.2.3 */
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}
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+ // Make sure the udp size is not smaller than the incoming message so that we
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+ // do not underflow
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+ if (udp_size < n) udp_size = n;
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+
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#ifdef HAVE_AUTH
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if (auth_dns)
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{
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diff --git a/src/rfc1035.c b/src/rfc1035.c
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index 917bac2..ae65702 100644
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--- a/src/rfc1035.c
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+++ b/src/rfc1035.c
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@@ -1182,8 +1182,8 @@ int add_resource_record(struct dns_header *header, char *limit, int *truncp, int
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va_end(ap); /* clean up variable argument pointer */
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j = p - sav - 2;
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- /* this has already been checked against limit before */
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- PUTSHORT(j, sav); /* Now, store real RDLength */
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+ /* this has already been checked against limit before */
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+ PUTSHORT(j, sav); /* Now, store real RDLength */
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/* check for overflow of buffer */
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if (limit && ((unsigned char *)limit - p) < 0)
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@@ -1243,6 +1243,8 @@ size_t answer_request(struct dns_header *header, char *limit, size_t qlen,
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int nxdomain = 0, auth = 1, trunc = 0, sec_data = 1;
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struct mx_srv_record *rec;
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size_t len;
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+ // Make sure we do not underflow here too.
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+ if (qlen > (limit - ((char *)header))) return 0;
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if (ntohs(header->ancount) != 0 ||
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ntohs(header->nscount) != 0 ||
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--
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2.9.5
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