88 lines
2.9 KiB
Diff
88 lines
2.9 KiB
Diff
From 5c281d182ecdd0a424b64f7698f32467f8f67b71 Mon Sep 17 00:00:00 2001
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From: Jukka Rissanen <jukka.rissanen@linux.intel.com>
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Date: Wed, 9 Aug 2017 10:16:46 +0300
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Subject: dnsproxy: Fix crash on malformed DNS response
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If the response query string is malformed, we might access memory
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pass the end of "name" variable in parse_response().
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CVE: CVE-2017-12865
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Upstream-Status: Backport [https://git.kernel.org/pub/scm/network/connman/connman.git/patch/?id=5c281d182ecdd0a424b64f7698f32467f8f67b71]
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Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>
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---
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src/dnsproxy.c | 16 ++++++++++------
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1 file changed, 10 insertions(+), 6 deletions(-)
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diff --git a/src/dnsproxy.c b/src/dnsproxy.c
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index 38ac5bf..40b4f15 100644
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--- a/src/dnsproxy.c
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+++ b/src/dnsproxy.c
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@@ -838,7 +838,7 @@ static struct cache_entry *cache_check(gpointer request, int *qtype, int proto)
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static int get_name(int counter,
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unsigned char *pkt, unsigned char *start, unsigned char *max,
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unsigned char *output, int output_max, int *output_len,
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- unsigned char **end, char *name, int *name_len)
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+ unsigned char **end, char *name, size_t max_name, int *name_len)
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{
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unsigned char *p;
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@@ -859,7 +859,7 @@ static int get_name(int counter,
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return get_name(counter + 1, pkt, pkt + offset, max,
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output, output_max, output_len, end,
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- name, name_len);
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+ name, max_name, name_len);
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} else {
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unsigned label_len = *p;
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@@ -869,6 +869,9 @@ static int get_name(int counter,
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if (*output_len > output_max)
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return -ENOBUFS;
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+ if ((*name_len + 1 + label_len + 1) > max_name)
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+ return -ENOBUFS;
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+
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/*
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* We need the original name in order to check
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* if this answer is the correct one.
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@@ -900,14 +903,14 @@ static int parse_rr(unsigned char *buf, unsigned char *start,
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unsigned char *response, unsigned int *response_size,
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uint16_t *type, uint16_t *class, int *ttl, int *rdlen,
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unsigned char **end,
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- char *name)
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+ char *name, size_t max_name)
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{
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struct domain_rr *rr;
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int err, offset;
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int name_len = 0, output_len = 0, max_rsp = *response_size;
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err = get_name(0, buf, start, max, response, max_rsp,
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- &output_len, end, name, &name_len);
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+ &output_len, end, name, max_name, &name_len);
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if (err < 0)
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return err;
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@@ -1033,7 +1036,8 @@ static int parse_response(unsigned char *buf, int buflen,
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memset(rsp, 0, sizeof(rsp));
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ret = parse_rr(buf, ptr, buf + buflen, rsp, &rsp_len,
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- type, class, ttl, &rdlen, &next, name);
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+ type, class, ttl, &rdlen, &next, name,
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+ sizeof(name) - 1);
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if (ret != 0) {
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err = ret;
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goto out;
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@@ -1099,7 +1103,7 @@ static int parse_response(unsigned char *buf, int buflen,
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*/
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ret = get_name(0, buf, next - rdlen, buf + buflen,
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rsp, rsp_len, &output_len, &end,
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- name, &name_len);
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+ name, sizeof(name) - 1, &name_len);
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if (ret != 0) {
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/* just ignore the error at this point */
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ptr = next;
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--
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cgit v1.1
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