Fix return values when adding serverinfo fails.

Reviewed-by: NRich Salz <rsalz@openssl.org>
MR #1128

ssl/ssl_rsa.c

@@ -747,31 +747,31 @@ static int serverinfo_find_extension(const unsigned char *serverinfo,
     *extension_data = NULL;
     *extension_length = 0;
     if (serverinfo == NULL || serverinfo_length == 0)
-        return 0;
+        return -1;
     for (;;) {
         unsigned int type = 0;
         size_t len = 0;
 
         /* end of serverinfo */
         if (serverinfo_length == 0)
-            return -1;          /* Extension not found */
+            return 0;           /* Extension not found */
 
         /* read 2-byte type field */
         if (serverinfo_length < 2)
-            return 0;           /* Error */
+            return -1;          /* Error */
         type = (serverinfo[0] << 8) + serverinfo[1];
         serverinfo += 2;
         serverinfo_length -= 2;
 
         /* read 2-byte len field */
         if (serverinfo_length < 2)
-            return 0;           /* Error */
+            return -1;          /* Error */
         len = (serverinfo[0] << 8) + serverinfo[1];
         serverinfo += 2;
         serverinfo_length -= 2;
 
         if (len > serverinfo_length)
-            return 0;           /* Error */
+            return -1;          /* Error */
 
         if (type == extension_type) {
             *extension_data = serverinfo;
@@ -811,10 +811,12 @@ static int serverinfo_srv_add_cb(SSL *s, unsigned int ext_type,
         /* Find the relevant extension from the serverinfo */
         int retval = serverinfo_find_extension(serverinfo, serverinfo_length,
                                                ext_type, out, outlen);
+        if (retval == -1) {
+            *al = SSL_AD_DECODE_ERROR;
+            return -1;          /* Error */
+        }
         if (retval == 0)
-            return 0;           /* Error */
-        if (retval == -1)
-            return -1;          /* No extension found, don't send extension */
+            return 0;           /* No extension found, don't send extension */
         return 1;               /* Send extension */
     }
     return -1;                  /* No serverinfo data found, don't send