Added a test for null (zero) integers in MPI scanning.

diff --git a/lib/gnutls_mpi.c b/lib/gnutls_mpi.c
index 2dcdc3a2dc85bd9932dc3baa226af0652704bf73..1b27f172fa1b70114d2e7ccbd91e7b48f737bce6 100644 (file)
--- a/lib/gnutls_mpi.c
+++ b/lib/gnutls_mpi.c
@@ -36,12 +36,38 @@ void _gnutls_mpi_release( GNUTLS_MPI* x) {
        *x=NULL;
 }
 
+/* returns zero on success
+ */
 int _gnutls_mpi_scan( GNUTLS_MPI *ret_mpi, const opaque *buffer, size_t *nbytes ) {
-       return gcry_mpi_scan( ret_mpi, GCRYMPI_FMT_USG, buffer, nbytes);
+       int ret;
+       
+       ret = gcry_mpi_scan( ret_mpi, GCRYMPI_FMT_USG, buffer, nbytes);
+       if (ret) return ret;
+       
+       /* MPIs with 0 bits are illegal
+        */
+       if (_gnutls_mpi_get_nbits( *ret_mpi) == 0) {
+               _gnutls_mpi_release( ret_mpi);
+               return 1;
+       }
+
+       return 0;
 }
 
 int _gnutls_mpi_scan_pgp( GNUTLS_MPI *ret_mpi, const opaque *buffer, size_t *nbytes ) {
-       return gcry_mpi_scan( ret_mpi, GCRYMPI_FMT_PGP, buffer, nbytes);
+int ret;
+       ret = gcry_mpi_scan( ret_mpi, GCRYMPI_FMT_PGP, buffer, nbytes);
+
+       if (ret) return ret;
+
+       /* MPIs with 0 bits are illegal
+        */
+       if (_gnutls_mpi_get_nbits( *ret_mpi) == 0) {
+               _gnutls_mpi_release( ret_mpi);
+               return 1;
+       }
+
+       return 0;
 }
 
 int _gnutls_mpi_print( opaque *buffer, size_t *nbytes, const GNUTLS_MPI a ) {