Change functions to pass in a limit rather than calculate it

Some extension handling functions were passing in a pointer to the start
of the data, plus the length in order to calculate the end, rather than
just passing in the end to start with. This change makes things a little
more readable.

Reviewed-by: Emilia Käsper <emilia@openssl.org>

diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c
index acd3b9e964a239b8b01f7aa84179c8e4f09a0e14..a355fde047cdb21b3e7fea263cb24133425bff6b 100644 (file)
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -1231,7 +1231,7 @@ int ssl3_get_client_hello(SSL *s)
 #ifndef OPENSSL_NO_TLSEXT
     /* TLS extensions */
     if (s->version >= SSL3_VERSION) {
-        if (!ssl_parse_clienthello_tlsext(s, &p, d, n)) {
+        if (!ssl_parse_clienthello_tlsext(s, &p, d + n)) {
             SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_PARSE_TLSEXT);
             goto err;
         }

diff --git a/ssl/ssl_locl.h b/ssl/ssl_locl.h
index 6c2c551e5e341e05fd44520ccb411895537021a7..1caf83b8a6ef29faf29bf1b1fedb11e7ee345f7b 100644 (file)
--- a/ssl/ssl_locl.h
+++ b/ssl/ssl_locl.h
@@ -1366,7 +1366,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf,
 unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf,
                                           unsigned char *limit, int *al);
 int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **data,
-                                 unsigned char *d, int n);
+                                 unsigned char *limit);
 int tls1_set_server_sigalgs(SSL *s);
 int ssl_check_clienthello_tlsext_late(SSL *s);
 int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **data,

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index 33af933ea934c2828527d7b9618bf199b4c96f26..ba098483603d3a16523af90031b545cfde5a97de 100644 (file)
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -1837,7 +1837,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf,
  * 10.8..10.8.3 (which don't work).
  */
 static void ssl_check_for_safari(SSL *s, const unsigned char *data,
-                                 const unsigned char *d, int n)
+                                 const unsigned char *limit)
 {
     unsigned short type, size;
     static const unsigned char kSafariExtensionsBlock[] = {
@@ -1866,11 +1866,11 @@ static void ssl_check_for_safari(SSL *s, const unsigned char *data,
         0x02, 0x03,             /* SHA-1/ECDSA */
     };
 
-    if (data >= (d + n - 2))
+    if (data >= (limit - 2))
         return;
     data += 2;
 
-    if (data > (d + n - 4))
+    if (data > (limit - 4))
         return;
     n2s(data, type);
     n2s(data, size);
@@ -1878,7 +1878,7 @@ static void ssl_check_for_safari(SSL *s, const unsigned char *data,
     if (type != TLSEXT_TYPE_server_name)
         return;
 
-    if (data + size > d + n)
+    if (data + size > limit)
         return;
     data += size;
 
@@ -1886,7 +1886,7 @@ static void ssl_check_for_safari(SSL *s, const unsigned char *data,
         const size_t len1 = sizeof(kSafariExtensionsBlock);
         const size_t len2 = sizeof(kSafariTLS12ExtensionsBlock);
 
-        if (data + len1 + len2 != d + n)
+        if (data + len1 + len2 != limit)
             return;
         if (memcmp(data, kSafariExtensionsBlock, len1) != 0)
             return;
@@ -1895,7 +1895,7 @@ static void ssl_check_for_safari(SSL *s, const unsigned char *data,
     } else {
         const size_t len = sizeof(kSafariExtensionsBlock);
 
-        if (data + len != d + n)
+        if (data + len != limit)
             return;
         if (memcmp(data, kSafariExtensionsBlock, len) != 0)
             return;
@@ -1974,7 +1974,7 @@ static int tls1_alpn_handle_client_hello(SSL *s, const unsigned char *data,
 }
 
 static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
-                                       unsigned char *d, int n, int *al)
+                                       unsigned char *limit, int *al)
 {
     unsigned short type;
     unsigned short size;
@@ -1999,7 +1999,7 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
 
 # ifndef OPENSSL_NO_EC
     if (s->options & SSL_OP_SAFARI_ECDHE_ECDSA_BUG)
-        ssl_check_for_safari(s, data, d, n);
+        ssl_check_for_safari(s, data, limit);
 # endif                         /* !OPENSSL_NO_EC */
 
     /* Clear any signature algorithms extension received */
@@ -2016,22 +2016,22 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
 
     s->srtp_profile = NULL;
 
-    if (data == d + n)
+    if (data == limit)
         goto ri_check;
 
-    if (data > (d + n - 2))
+    if (data > (limit - 2))
         goto err;
 
     n2s(data, len);
 
-    if (data + len != d + n)
+    if (data + len != limit)
         goto err;
 
-    while (data <= (d + n - 4)) {
+    while (data <= (limit - 4)) {
         n2s(data, type);
         n2s(data, size);
 
-        if (data + size > (d + n))
+        if (data + size > (limit))
             goto err;
 # if 0
         fprintf(stderr, "Received extension type %d size %d\n", type, size);
@@ -2405,7 +2405,7 @@ static int ssl_scan_clienthello_tlsext(SSL *s, unsigned char **p,
     }
 
     /* Spurious data on the end */
-    if (data != d + n)
+    if (data != limit)
         goto err;
 
     *p = data;
@@ -2465,8 +2465,8 @@ static int ssl_scan_clienthello_custom_tlsext(SSL *s,
     return 1;
 }
 
-int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
-                                 int n)
+int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p,
+                                 unsigned char *limit)
 {
     int al = -1;
     unsigned char *ptmp = *p;
@@ -2476,7 +2476,7 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
      * switch the parent context using SSL_set_SSL_CTX and custom extensions
      * need to be handled by the new SSL_CTX structure.
      */
-    if (ssl_scan_clienthello_tlsext(s, p, d, n, &al) <= 0) {
+    if (ssl_scan_clienthello_tlsext(s, p, limit, &al) <= 0) {
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
         return 0;
     }
@@ -2487,7 +2487,7 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d,
     }
 
     custom_ext_init(&s->cert->srv_ext);
-    if (ssl_scan_clienthello_custom_tlsext(s, ptmp, d + n, &al) <= 0) {
+    if (ssl_scan_clienthello_custom_tlsext(s, ptmp, limit, &al) <= 0) {
         ssl3_send_alert(s, SSL3_AL_FATAL, al);
         return 0;
     }