Check for integer overflow in content-length.

Also only allow single digits in the HTTP version.
Need multiple digits? Convince me.

http_parser.rl

@@ -23,6 +23,7 @@
  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 
  */
 #include "http_parser.h"
+#include <limits.h>
 #ifndef NDEBUG
 # include <assert.h>
 #endif
@@ -198,6 +199,10 @@ do {                                                                 \
   }
 
   action content_length {
+    if (parser->content_length > INT_MAX) {
+      parser->buffer_overflow = TRUE;
+      return 0;
+    }
     parser->content_length *= 10;
     parser->content_length += *p - '0';
   }
@@ -308,7 +313,7 @@ do {                                                                 \
            | "UNLOCK"    %{ parser->method = HTTP_UNLOCK;    }
            ); # Not allowing extension methods
 
-  HTTP_Version = "HTTP/" digit+ $version_major "." digit+ $version_minor;
+  HTTP_Version = "HTTP/" digit $version_major "." digit $version_minor;
 
   scheme = ( alpha | digit | "+" | "-" | "." )* ;
   absolute_uri = (scheme ":" (uchar | reserved )*);