Pull out, rework and dedup the code that determines the highest shared

version.

ok beck@ doug@

4 files changed, 62 insertions, 79 deletions

diff --git a/src/lib/libssl/s23_clnt.c b/src/lib/libssl/s23_clnt.c
index 2511a94b28..c4fad5b011 100644
--- a/src/lib/libssl/s23_clnt.c
+++ b/src/lib/libssl/s23_clnt.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s23_clnt.c,v 1.48 2016/12/30 16:57:01 jsing Exp $ */
+/* $OpenBSD: s23_clnt.c,v 1.49 2017/01/03 16:57:15 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -239,7 +239,7 @@ ssl23_client_hello(SSL *s)
         if (s->state == SSL23_ST_CW_CLNT_HELLO_A) {
                 arc4random_buf(s->s3->client_random, SSL3_RANDOM_SIZE);
 
-                if (ssl_enabled_version_range(s, NULL, &version) == -1) {
+                if (ssl_enabled_version_range(s, NULL, &version) != 1) {
                         SSLerr(SSL_F_SSL23_CLIENT_HELLO,
                             SSL_R_NO_PROTOCOLS_AVAILABLE);
                         return (-1);
diff --git a/src/lib/libssl/s23_srvr.c b/src/lib/libssl/s23_srvr.c
index edb1f637ea..35bc271f00 100644
--- a/src/lib/libssl/s23_srvr.c
+++ b/src/lib/libssl/s23_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s23_srvr.c,v 1.48 2016/11/04 18:33:11 guenther Exp $ */
+/* $OpenBSD: s23_srvr.c,v 1.49 2017/01/03 16:57:15 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -220,17 +220,16 @@ ssl23_get_client_hello(SSL *s)
          *  6-8   length           > Client Hello message
          *  9/10  client_version  /
          */
+        uint16_t client_version = 0;
+        uint16_t shared_version;
         unsigned char *p, *d, *d_len, *dd;
         unsigned int i;
         unsigned int csl, sil, cl;
         int n = 0, j;
         int type = 0;
-        int v[2];
 
         if (s->state == SSL23_ST_SR_CLNT_HELLO_A) {
                 /* read the initial header */
-                v[0] = v[1] = 0;
-
                 if (!ssl3_setup_buffers(s))
                         return -1;
 
@@ -246,37 +245,14 @@ ssl23_get_client_hello(SSL *s)
                         /*
                          * SSLv2 header
                          */
-                        if ((p[3] == 0x00) && (p[4] == 0x02)) {
-                                /* SSLv2 support has been removed */
+                        client_version = p[3] << 8 | p[4];
+
+                        if (!ssl_max_shared_version(s, client_version,
+                            &shared_version))
                                 goto unsupported;
 
-                        } else if (p[3] == SSL3_VERSION_MAJOR) {
-                                v[0] = p[3];
-                                v[1] = p[4];
-                                /* SSLv3/TLS */
-
-                                if (p[4] >= TLS1_VERSION_MINOR) {
-                                        if (p[4] >= TLS1_2_VERSION_MINOR &&
-                                            !(s->options & SSL_OP_NO_TLSv1_2)) {
-                                                s->version = TLS1_2_VERSION;
-                                                s->state = SSL23_ST_SR_CLNT_HELLO_B;
-                                        } else if (p[4] >= TLS1_1_VERSION_MINOR &&
-                                            !(s->options & SSL_OP_NO_TLSv1_1)) {
-                                                s->version = TLS1_1_VERSION;
-                                                /* type=2; */ /* done later to survive restarts */
-                                                s->state = SSL23_ST_SR_CLNT_HELLO_B;
-                                        } else if (!(s->options & SSL_OP_NO_TLSv1)) {
-                                                s->version = TLS1_VERSION;
-                                                /* type=2; */ /* done later to survive restarts */
-                                                s->state = SSL23_ST_SR_CLNT_HELLO_B;
-                                        } else {
-                                                goto unsupported;
-                                        }
-                                } else {
-                                        /* SSLv3 support has been removed */
-                                        goto unsupported;
-                                }
-                        }
+                        s->version = shared_version;
+                        s->state = SSL23_ST_SR_CLNT_HELLO_B;
                 } else if ((p[0] == SSL3_RT_HANDSHAKE) &&
                     (p[1] == SSL3_VERSION_MAJOR) &&
                     (p[5] == SSL3_MT_CLIENT_HELLO) &&
@@ -286,7 +262,6 @@ ssl23_get_client_hello(SSL *s)
                          * SSLv3 or tls1 header
                          */
 
-                        v[0] = p[1]; /* major version (= SSL3_VERSION_MAJOR) */
                         /* We must look at client_version inside the Client Hello message
                          * to get the correct minor version.
                          * However if we have only a pathologically small fragment of the
@@ -300,43 +275,21 @@ ssl23_get_client_hello(SSL *s)
                                     SSL_R_RECORD_TOO_SMALL);
                                 return -1;
                         }
-                        /* if major version number > 3 set minor to a value
-                         * which will use the highest version 3 we support.
-                         * If TLS 2.0 ever appears we will need to revise
-                         * this....
-                         */
-                        if (p[9] > SSL3_VERSION_MAJOR)
-                                v[1] = 0xff;
-                        else
-                                v[1] = p[10]; /* minor version according to client_version */
-                        if (v[1] >= TLS1_VERSION_MINOR) {
-                                if (v[1] >= TLS1_2_VERSION_MINOR &&
-                                    !(s->options & SSL_OP_NO_TLSv1_2)) {
-                                        s->version = TLS1_2_VERSION;
-                                        type = 3;
-                                } else if (v[1] >= TLS1_1_VERSION_MINOR &&
-                                    !(s->options & SSL_OP_NO_TLSv1_1)) {
-                                        s->version = TLS1_1_VERSION;
-                                        type = 3;
-                                } else if (!(s->options & SSL_OP_NO_TLSv1)) {
-                                        s->version = TLS1_VERSION;
-                                        type = 3;
-                                } else {
-                                        goto unsupported;
-                                }
-                        } else {
-                                /* SSLv3 */
-                                if (!(s->options & SSL_OP_NO_TLSv1)) {
-                                        /* we won't be able to use TLS of course,
-                                         * but this will send an appropriate alert */
-                                        s->version = TLS1_VERSION;
-                                        type = 3;
-                                } else {
+                        client_version = p[9] << 8 | p[10];
+
+                        if (!ssl_max_shared_version(s, client_version,
+                            &shared_version)) {
+                                if (s->options & SSL_OP_NO_TLSv1)
                                         goto unsupported;
-                                }
+                                /*
+                                 * We won't be able to use TLS of course,
+                                 * but this will send an appropriate alert.
+                                 */
+                                shared_version = TLS1_VERSION;
                         }
-                }
-                else if ((strncmp("GET ", (char *)p, 4) == 0) ||
+                        s->version = shared_version;
+                        type = 3;
+                } else if ((strncmp("GET ", (char *)p, 4) == 0) ||
                     (strncmp("POST ",(char *)p, 5) == 0) ||
                     (strncmp("HEAD ",(char *)p, 5) == 0) ||
                     (strncmp("PUT ", (char *)p, 4) == 0)) {
@@ -362,8 +315,7 @@ ssl23_get_client_hello(SSL *s)
 
                 type = 2;
                 p = s->packet;
-                v[0] = p[3]; /* == SSL3_VERSION_MAJOR */
-                v[1] = p[4];
+                client_version = p[3] << 8 | p[4];
 
                 /* An SSLv3/TLSv1 backwards-compatible CLIENT-HELLO in an SSLv2
                  * header is sent directly on the wire, not wrapped as a TLS
@@ -421,8 +373,8 @@ ssl23_get_client_hello(SSL *s)
                 d += 3;
 
                 /* client_version */
-                *(d++) = SSL3_VERSION_MAJOR; /* == v[0] */
-                *(d++) = v[1];
+                *(d++) = client_version >> 8;
+                *(d++) = client_version & 0xff;
 
                 /* lets populate the random area */
                 /* get the challenge_length */
diff --git a/src/lib/libssl/ssl_lib.c b/src/lib/libssl/ssl_lib.c
index 11f46161a9..a4ca1afb1d 100644
--- a/src/lib/libssl/ssl_lib.c
+++ b/src/lib/libssl/ssl_lib.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_lib.c,v 1.123 2016/12/30 16:57:01 jsing Exp $ */
+/* $OpenBSD: ssl_lib.c,v 1.124 2017/01/03 16:57:15 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -2516,14 +2516,44 @@ ssl_enabled_version_range(SSL *s, uint16_t *min_ver, uint16_t *max_ver)
 
         /* Everything has been disabled... */
         if (min_version == 0 || max_version == 0)
-                return -1;
+                return 0;
 
         if (min_ver != NULL)
                 *min_ver = min_version;
         if (max_ver != NULL)
                 *max_ver = max_version;
 
-        return 0;
+        return 1;
+}
+
+int
+ssl_max_shared_version(SSL *s, uint16_t peer_ver, uint16_t *max_ver)
+{
+        uint16_t min_version, max_version, shared_version;
+
+        *max_ver = 0;
+
+        if (peer_ver >= TLS1_2_VERSION)
+                shared_version = TLS1_2_VERSION;
+        else if (peer_ver >= TLS1_1_VERSION)
+                shared_version = TLS1_1_VERSION;
+        else if (peer_ver >= TLS1_VERSION)
+                shared_version = TLS1_VERSION;
+        else
+                return 0;
+
+        if (!ssl_enabled_version_range(s, &min_version, &max_version))
+                return 0;
+
+        if (shared_version < min_version)
+                return 0;
+
+        if (shared_version > max_version)
+                shared_version = max_version;
+
+        *max_ver = shared_version;
+
+        return 1;
 }
 
 uint16_t
diff --git a/src/lib/libssl/ssl_locl.h b/src/lib/libssl/ssl_locl.h
index e8fbd23572..800c56e31b 100644
--- a/src/lib/libssl/ssl_locl.h
+++ b/src/lib/libssl/ssl_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.143 2016/12/30 16:57:01 jsing Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.144 2017/01/03 16:57:15 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -498,6 +498,7 @@ extern SSL_CIPHER ssl3_ciphers[];
 
 const char *ssl_version_string(int ver);
 int ssl_enabled_version_range(SSL *s, uint16_t *min_ver, uint16_t *max_ver);
+int ssl_max_shared_version(SSL *s, uint16_t peer_ver, uint16_t *max_ver);
 uint16_t ssl_max_server_version(SSL *s);
 
 extern SSL3_ENC_METHOD DTLSv1_enc_data;