* grub-core/lib/libgcrypt/mpi/mpih-div.c (_gcry_mpih_divrem):

Use grub_fatal rather than divide by zero.
	* grub-core/lib/libgcrypt/mpi/mpi-pow.c (gcry_mpi_powm): Likewise.

grub-core/lib/libgcrypt/mpi/mpi-pow.c

@@ -77,7 +77,7 @@ gcry_mpi_powm (gcry_mpi_t res,
   ep = expo->d;
 
   if (!msize)
-    msize = 1 / msize;	    /* Provoke a signal.  */
+    grub_fatal ("mpi division by zero");
 
   if (!esize)
     {

grub-core/lib/libgcrypt/mpi/mpih-div.c

@@ -214,7 +214,8 @@ _gcry_mpih_divrem( mpi_ptr_t qp, mpi_size_t qextra_limbs,
       case 0:
 	/* We are asked to divide by zero, so go ahead and do it!  (To make
 	   the compiler not remove this statement, return the value.)  */
-	return 1 / dsize;
+	grub_fatal ("mpi division by zero");
+	return 0;
 
       case 1:
 	{