Fix limit checks in ssl_add_clienthello_tlsext and ssl_add_serverhello_tlsext.

Some of the limit checks reference p rather than ret. p is the original buffer
position, not the current one. Fix those and rename p to orig so it's clearer.

BUF_MEM_grow allocates 4/3 the size requested, so it doesn't overflow the
actual allocation.

BUG=none

Review URL: https://codereview.chromium.org/258143004

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/openssl@267648 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

4 files changed, 145 insertions, 18 deletions

diff --git a/README.chromium b/README.chromium
index d994e1b..dcc03de 100644
--- a/README.chromium
+++ b/README.chromium
@@ -198,6 +198,10 @@ located in patches.chromium/. Currently this consists of:
 
   mac_osx32_assembly.patch
     Add support for 32 bit OS X with assembly optimization.
+
+  fix_limit_checks.patch
+    Fix limit checks in writing extensions. BUF_MEM_grow allocates 4/3 the size
+    requested, so it doesn't overflow the actual allocation.
      
 **************************************************************************
 Adding new Chromium patches:
diff --git a/openssl/ssl/ssl_locl.h b/openssl/ssl/ssl_locl.h
index 3732825..4e27d9e 100644
--- a/openssl/ssl/ssl_locl.h
+++ b/openssl/ssl/ssl_locl.h
@@ -1127,8 +1127,8 @@ int tls1_ec_nid2curve_id(int nid);
 #endif /* OPENSSL_NO_EC */
 
 #ifndef OPENSSL_NO_TLSEXT
-unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit); 
-unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit); 
+unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit); 
+unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit); 
 int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n, int *al);
 int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n, int *al);
 int ssl_prepare_clienthello_tlsext(SSL *s);
diff --git a/openssl/ssl/t1_lib.c b/openssl/ssl/t1_lib.c
index 7a507f9..a53d56b 100644
--- a/openssl/ssl/t1_lib.c
+++ b/openssl/ssl/t1_lib.c
@@ -341,15 +341,16 @@ int tls12_get_req_sig_algs(SSL *s, unsigned char *p)
 	return (int)slen;
 	}
 
-unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
+unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
 	{
 	int extdatalen=0;
-	unsigned char *ret = p;
+	unsigned char *orig = buf;
+	unsigned char *ret = buf;
 
 	/* don't add extensions for SSLv3 unless doing secure renegotiation */
 	if (s->client_version == SSL3_VERSION
 					&& !s->s3->send_connection_binding)
-		return p;
+		return orig;
 
 	ret+=2;
 
@@ -398,7 +399,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
               return NULL;
               }
 
-          if((limit - p - 4 - el) < 0) return NULL;
+          if((limit - ret - 4 - el) < 0) return NULL;
           
           s2n(TLSEXT_TYPE_renegotiate,ret);
           s2n(el,ret);
@@ -647,7 +648,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
 
                 ssl_add_clienthello_use_srtp_ext(s, 0, &el, 0);
                 
-                if((limit - p - 4 - el) < 0) return NULL;
+                if((limit - ret - 4 - el) < 0) return NULL;
 
                 s2n(TLSEXT_TYPE_use_srtp,ret);
                 s2n(el,ret);
@@ -686,24 +687,25 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
 	}
 
 
-	if ((extdatalen = ret-p-2)== 0) 
-		return p;
+	if ((extdatalen = ret-orig-2)== 0) 
+		return orig;
 
-	s2n(extdatalen,p);
+	s2n(extdatalen, orig);
 	return ret;
 	}
 
-unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
+unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
 	{
 	int extdatalen=0;
-	unsigned char *ret = p;
+	unsigned char *orig = buf;
+	unsigned char *ret = buf;
 #ifndef OPENSSL_NO_NEXTPROTONEG
 	int next_proto_neg_seen;
 #endif
 
 	/* don't add extensions for SSLv3, unless doing secure renegotiation */
 	if (s->version == SSL3_VERSION && !s->s3->send_connection_binding)
-		return p;
+		return orig;
 	
 	ret+=2;
 	if (ret>=limit) return NULL; /* this really never occurs, but ... */
@@ -726,7 +728,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
               return NULL;
               }
 
-          if((limit - p - 4 - el) < 0) return NULL;
+          if((limit - ret - 4 - el) < 0) return NULL;
           
           s2n(TLSEXT_TYPE_renegotiate,ret);
           s2n(el,ret);
@@ -806,7 +808,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
 
                 ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0);
                 
-                if((limit - p - 4 - el) < 0) return NULL;
+                if((limit - ret - 4 - el) < 0) return NULL;
 
                 s2n(TLSEXT_TYPE_use_srtp,ret);
                 s2n(el,ret);
@@ -885,10 +887,10 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
 		s2n(0,ret);
 		}
 
-	if ((extdatalen = ret-p-2)== 0) 
-		return p;
+	if ((extdatalen = ret-orig-2)== 0) 
+		return orig;
 
-	s2n(extdatalen,p);
+	s2n(extdatalen, orig);
 	return ret;
 	}
 
diff --git a/patches.chromium/0011-fix_limit_checks.patch b/patches.chromium/0011-fix_limit_checks.patch
new file mode 100644
index 0000000..b4ab8a3
--- /dev/null
+++ b/patches.chromium/0011-fix_limit_checks.patch
@@ -0,0 +1,121 @@
+diff --git android-openssl.orig/ssl/ssl_locl.h android-openssl/ssl/ssl_locl.h
+index 3732825..4e27d9e 100644
+--- android-openssl.orig/ssl/ssl_locl.h
++++ android-openssl/ssl/ssl_locl.h
+@@ -1127,8 +1127,8 @@ int tls1_ec_nid2curve_id(int nid);
+ #endif /* OPENSSL_NO_EC */
+ 
+ #ifndef OPENSSL_NO_TLSEXT
+-unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit); 
+-unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit); 
++unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit); 
++unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit); 
+ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n, int *al);
+ int ssl_parse_serverhello_tlsext(SSL *s, unsigned char **data, unsigned char *d, int n, int *al);
+ int ssl_prepare_clienthello_tlsext(SSL *s);
+diff --git android-openssl.orig/ssl/t1_lib.c android-openssl/ssl/t1_lib.c
+index 7a507f9..a53d56b 100644
+--- android-openssl.orig/ssl/t1_lib.c
++++ android-openssl/ssl/t1_lib.c
+@@ -341,15 +341,16 @@ int tls12_get_req_sig_algs(SSL *s, unsigned char *p)
+ 	return (int)slen;
+ 	}
+ 
+-unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
++unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
+ 	{
+ 	int extdatalen=0;
+-	unsigned char *ret = p;
++	unsigned char *orig = buf;
++	unsigned char *ret = buf;
+ 
+ 	/* don't add extensions for SSLv3 unless doing secure renegotiation */
+ 	if (s->client_version == SSL3_VERSION
+ 					&& !s->s3->send_connection_binding)
+-		return p;
++		return orig;
+ 
+ 	ret+=2;
+ 
+@@ -398,7 +399,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
+               return NULL;
+               }
+ 
+-          if((limit - p - 4 - el) < 0) return NULL;
++          if((limit - ret - 4 - el) < 0) return NULL;
+           
+           s2n(TLSEXT_TYPE_renegotiate,ret);
+           s2n(el,ret);
+@@ -647,7 +648,7 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
+ 
+                 ssl_add_clienthello_use_srtp_ext(s, 0, &el, 0);
+                 
+-                if((limit - p - 4 - el) < 0) return NULL;
++                if((limit - ret - 4 - el) < 0) return NULL;
+ 
+                 s2n(TLSEXT_TYPE_use_srtp,ret);
+                 s2n(el,ret);
+@@ -686,24 +687,25 @@ unsigned char *ssl_add_clienthello_tlsext(SSL *s, unsigned char *p, unsigned cha
+ 	}
+ 
+ 
+-	if ((extdatalen = ret-p-2)== 0) 
+-		return p;
++	if ((extdatalen = ret-orig-2)== 0) 
++		return orig;
+ 
+-	s2n(extdatalen,p);
++	s2n(extdatalen, orig);
+ 	return ret;
+ 	}
+ 
+-unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned char *limit)
++unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf, unsigned char *limit)
+ 	{
+ 	int extdatalen=0;
+-	unsigned char *ret = p;
++	unsigned char *orig = buf;
++	unsigned char *ret = buf;
+ #ifndef OPENSSL_NO_NEXTPROTONEG
+ 	int next_proto_neg_seen;
+ #endif
+ 
+ 	/* don't add extensions for SSLv3, unless doing secure renegotiation */
+ 	if (s->version == SSL3_VERSION && !s->s3->send_connection_binding)
+-		return p;
++		return orig;
+ 	
+ 	ret+=2;
+ 	if (ret>=limit) return NULL; /* this really never occurs, but ... */
+@@ -726,7 +728,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
+               return NULL;
+               }
+ 
+-          if((limit - p - 4 - el) < 0) return NULL;
++          if((limit - ret - 4 - el) < 0) return NULL;
+           
+           s2n(TLSEXT_TYPE_renegotiate,ret);
+           s2n(el,ret);
+@@ -806,7 +808,7 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
+ 
+                 ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0);
+                 
+-                if((limit - p - 4 - el) < 0) return NULL;
++                if((limit - ret - 4 - el) < 0) return NULL;
+ 
+                 s2n(TLSEXT_TYPE_use_srtp,ret);
+                 s2n(el,ret);
+@@ -885,10 +887,10 @@ unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *p, unsigned cha
+ 		s2n(0,ret);
+ 		}
+ 
+-	if ((extdatalen = ret-p-2)== 0) 
+-		return p;
++	if ((extdatalen = ret-orig-2)== 0) 
++		return orig;
+ 
+-	s2n(extdatalen,p);
++	s2n(extdatalen, orig);
+ 	return ret;
+ 	}
+