aboutsummaryrefslogtreecommitdiffstats
path: root/meta/recipes-connectivity/bind/bind/CVE-2016-2088.patch
blob: 1b84d46b78d101a810d17cb53a232b2d98b12949 (plain)
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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
CVE-2016-2088

Backport commit d7ff9a1c41bf0ba9773cb3adb08b48b9fd57c956 from the
v9_10_3_patch branch.

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-2088
https://kb.isc.org/article/AA-01351

CVE: CVE-2016-2088
Upstream-Status: Backport
Signed-off-by: Jussi Kukkonen <jussi.kukkonen@intel.com>


Original commit message from Mark Andrews <marka@isc.org> below:

4322.   [security]      Duplicate EDNS COOKIE options in a response could
                        trigger an assertion failure. (CVE-2016-2088)
                        [RT #41809]

(cherry picked from commit 455c0848f80a8acda27aad1466c72987cafaa029)
(cherry picked from commit 7cd300abd6ee8b8ee8730593daf742ba53f90bc3)
---
 CHANGES            |  4 ++++
 bin/dig/dighost.c  |  9 +++++++++
 bin/named/client.c | 33 +++++++++++++++++++++++----------
 doc/arm/notes.xml  |  7 +++++++
 lib/dns/resolver.c | 14 +++++++++++++-
 5 files changed, 56 insertions(+), 11 deletions(-)

diff --git a/CHANGES b/CHANGES
index c5b5d2b..d2e3360 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,7 @@
+4322.  [security]      Duplicate EDNS COOKIE options in a response could
+                       trigger an assertion failure. (CVE-2016-2088)
+                       [RT #41809]
+
 4319.  [security]      Fix resolver assertion failure due to improper
                        DNAME handling when parsing fetch reply messages.
                        (CVE-2016-1286) [RT #41753]
diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index ca82f8e..340904f 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -3458,6 +3458,7 @@ process_opt(dig_lookup_t *l, dns_message_t *msg) {
 	isc_buffer_t optbuf;
 	isc_uint16_t optcode, optlen;
 	dns_rdataset_t *opt = msg->opt;
+	isc_boolean_t seen_cookie = ISC_FALSE;
 
 	result = dns_rdataset_first(opt);
 	if (result == ISC_R_SUCCESS) {
@@ -3470,7 +3471,15 @@ process_opt(dig_lookup_t *l, dns_message_t *msg) {
 			optlen = isc_buffer_getuint16(&optbuf);
 			switch (optcode) {
 			case DNS_OPT_COOKIE:
+				/*
+				 * Only process the first cookie option.
+				 */
+				if (seen_cookie) {
+					isc_buffer_forward(&optbuf, optlen);
+					break;
+				}
 				process_sit(l, msg, &optbuf, optlen);
+				seen_cookie = ISC_TRUE;
 				break;
 			default:
 				isc_buffer_forward(&optbuf, optlen);
diff --git a/bin/named/client.c b/bin/named/client.c
index 683305c..0d7331a 100644
--- a/bin/named/client.c
+++ b/bin/named/client.c
@@ -120,7 +120,10 @@
  */
 #endif
 
-#define SIT_SIZE 24U /* 8 + 4 + 4 + 8 */
+#define COOKIE_SIZE 24U /* 8 + 4 + 4 + 8 */
+
+#define WANTNSID(x) (((x)->attributes & NS_CLIENTATTR_WANTNSID) != 0)
+#define WANTEXPIRE(x) (((x)->attributes & NS_CLIENTATTR_WANTEXPIRE) != 0)
 
 /*% nameserver client manager structure */
 struct ns_clientmgr {
@@ -1395,7 +1398,7 @@ ns_client_addopt(ns_client_t *client, dns_message_t *message,
 {
 	char nsid[BUFSIZ], *nsidp;
 #ifdef ISC_PLATFORM_USESIT
-	unsigned char sit[SIT_SIZE];
+	unsigned char sit[COOKIE_SIZE];
 #endif
 	isc_result_t result;
 	dns_view_t *view;
@@ -1420,7 +1423,7 @@ ns_client_addopt(ns_client_t *client, dns_message_t *message,
 	flags = client->extflags & DNS_MESSAGEEXTFLAG_REPLYPRESERVE;
 
 	/* Set EDNS options if applicable */
-	if ((client->attributes & NS_CLIENTATTR_WANTNSID) != 0 &&
+	if (WANTNSID(client) &&
 	    (ns_g_server->server_id != NULL ||
 	     ns_g_server->server_usehostname)) {
 		if (ns_g_server->server_usehostname) {
@@ -1453,7 +1456,7 @@ ns_client_addopt(ns_client_t *client, dns_message_t *message,
 
 		INSIST(count < DNS_EDNSOPTIONS);
 		ednsopts[count].code = DNS_OPT_COOKIE;
-		ednsopts[count].length = SIT_SIZE;
+		ednsopts[count].length = COOKIE_SIZE;
 		ednsopts[count].value = sit;
 		count++;
 	}
@@ -1661,19 +1664,26 @@ compute_sit(ns_client_t *client, isc_uint32_t when, isc_uint32_t nonce,
 
 static void
 process_sit(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
-	unsigned char dbuf[SIT_SIZE];
+	unsigned char dbuf[COOKIE_SIZE];
 	unsigned char *old;
 	isc_stdtime_t now;
 	isc_uint32_t when;
 	isc_uint32_t nonce;
 	isc_buffer_t db;
 
+	/*
+	 * If we have already seen a ECS option skip this ECS option.
+	 */
+	if ((client->attributes & NS_CLIENTATTR_WANTSIT) != 0) {
+		isc_buffer_forward(buf, optlen);
+		return;
+	}
 	client->attributes |= NS_CLIENTATTR_WANTSIT;
 
 	isc_stats_increment(ns_g_server->nsstats,
 			    dns_nsstatscounter_sitopt);
 
-	if (optlen != SIT_SIZE) {
+	if (optlen != COOKIE_SIZE) {
 		/*
 		 * Not our token.
 		 */
@@ -1717,14 +1727,13 @@ process_sit(ns_client_t *client, isc_buffer_t *buf, size_t optlen) {
 	isc_buffer_init(&db, dbuf, sizeof(dbuf));
 	compute_sit(client, when, nonce, &db);
 
-	if (!isc_safe_memequal(old, dbuf, SIT_SIZE)) {
+	if (!isc_safe_memequal(old, dbuf, COOKIE_SIZE)) {
 		isc_stats_increment(ns_g_server->nsstats,
 				    dns_nsstatscounter_sitnomatch);
 		return;
 	}
 	isc_stats_increment(ns_g_server->nsstats,
 			    dns_nsstatscounter_sitmatch);
-
 	client->attributes |= NS_CLIENTATTR_HAVESIT;
 }
 #endif
@@ -1783,7 +1792,9 @@ process_opt(ns_client_t *client, dns_rdataset_t *opt) {
 			optlen = isc_buffer_getuint16(&optbuf);
 			switch (optcode) {
 			case DNS_OPT_NSID:
-				isc_stats_increment(ns_g_server->nsstats,
+				if (!WANTNSID(client))
+					isc_stats_increment(
+						    ns_g_server->nsstats,
 						    dns_nsstatscounter_nsidopt);
 				client->attributes |= NS_CLIENTATTR_WANTNSID;
 				isc_buffer_forward(&optbuf, optlen);
@@ -1794,7 +1805,9 @@ process_opt(ns_client_t *client, dns_rdataset_t *opt) {
 				break;
 #endif
 			case DNS_OPT_EXPIRE:
-				isc_stats_increment(ns_g_server->nsstats,
+				if (!WANTEXPIRE(client))
+					isc_stats_increment(
+						  ns_g_server->nsstats,
 						  dns_nsstatscounter_expireopt);
 				client->attributes |= NS_CLIENTATTR_WANTEXPIRE;
 				isc_buffer_forward(&optbuf, optlen);
diff --git a/doc/arm/notes.xml b/doc/arm/notes.xml
index ebf4f55..095eb5b 100644
--- a/doc/arm/notes.xml
+++ b/doc/arm/notes.xml
@@ -51,6 +51,13 @@
     <title>Security Fixes</title>
     <itemizedlist>
       <listitem>
+       <para>
+         Duplicate EDNS COOKIE options in a response could trigger
+         an assertion failure. This flaw is disclosed in CVE-2016-2088.
+         [RT #41809]
+       </para>
+      </listitem>
+      <listitem>
 	<para>
 	  Specific APL data could trigger an INSIST.  This flaw
 	  was discovered by Brian Mitchell and is disclosed in
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index a797e3f..ba1ae23 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -7502,7 +7502,9 @@ process_opt(resquery_t *query, dns_rdataset_t *opt) {
 	unsigned char *sit;
 	dns_adbaddrinfo_t *addrinfo;
 	unsigned char cookie[8];
+	isc_boolean_t seen_cookie = ISC_FALSE;
 #endif
+	isc_boolean_t seen_nsid = ISC_FALSE;
 
 	result = dns_rdataset_first(opt);
 	if (result == ISC_R_SUCCESS) {
@@ -7516,14 +7518,23 @@ process_opt(resquery_t *query, dns_rdataset_t *opt) {
 			INSIST(optlen <= isc_buffer_remaininglength(&optbuf));
 			switch (optcode) {
 			case DNS_OPT_NSID:
-				if (query->options & DNS_FETCHOPT_WANTNSID)
+				if (!seen_nsid &&
+				    query->options & DNS_FETCHOPT_WANTNSID)
 					log_nsid(&optbuf, optlen, query,
 						 ISC_LOG_DEBUG(3),
 						 query->fctx->res->mctx);
 				isc_buffer_forward(&optbuf, optlen);
+				seen_nsid = ISC_TRUE;
 				break;
 #ifdef ISC_PLATFORM_USESIT
 			case DNS_OPT_COOKIE:
+				/*
+				 * Only process the first cookie option.
+				 */
+				if (seen_cookie) {
+					isc_buffer_forward(&optbuf, optlen);
+					break;
+				}
 				sit = isc_buffer_current(&optbuf);
 				compute_cc(query, cookie, sizeof(cookie));
 				INSIST(query->fctx->rmessage->sitbad == 0 &&
@@ -7541,6 +7552,7 @@ process_opt(resquery_t *query, dns_rdataset_t *opt) {
 				isc_buffer_forward(&optbuf, optlen);
 				inc_stats(query->fctx->res,
 					  dns_resstatscounter_sitin);
+				seen_cookie = ISC_TRUE;
 				break;
 #endif
 			default:
-- 
2.1.4