Fixed a problem with shifting MPIs by 0.

Add a way to check whether the RNG is in fake mode.

2 files changed, 16 insertions, 1 deletions

diff --git a/mpi/ChangeLog b/mpi/ChangeLog
index 176ccf22..c670967e 100644
--- a/mpi/ChangeLog
+++ b/mpi/ChangeLog
@@ -1,3 +1,8 @@
+2006-08-25  Werner Koch  <wk@g10code.com>
+
+	* mpi-bit.c (gcry_mpi_rshift): Don't shift if N == 0 but do a
+	plain copy.
+
 2006-08-04  Werner Koch  <wk@g10code.com>
 
 	* mpi-bit.c (gcry_mpi_rshift): Rewritten to remove the limitation
diff --git a/mpi/mpi-bit.c b/mpi/mpi-bit.c
index d16eaae1..fe4895dc 100644
--- a/mpi/mpi-bit.c
+++ b/mpi/mpi-bit.c
@@ -256,7 +256,17 @@ gcry_mpi_rshift ( gcry_mpi_t x, gcry_mpi_t a, unsigned int n )
       x->nlimbs = xsize;
       
       if ( xsize )
-        _gcry_mpih_rshift (x->d, a->d, x->nlimbs, nbits );
+        {
+          if (nbits )
+            _gcry_mpih_rshift (x->d, a->d, x->nlimbs, nbits );
+          else
+            {
+              /* The rshift helper function is not specified for
+                 NBITS==0, thus we do a plain copy here. */
+              for (i=0; i < x->nlimbs; i++ )
+                x->d[i] = a->d[i];
+            }
+        }
     }
   MPN_NORMALIZE (x->d, x->nlimbs);
 }