Fix unchecked return in bignum

Signed-off-by: Paul Elliott <[email protected]>

ChangeLog.d/fix_bignum_unchecked_return.txt

@@ -0,0 +1,2 @@
+Bugfix
+   * Fix unchecked return in bignum module.

library/bignum.c

@@ -1666,8 +1666,7 @@ int mbedtls_mpi_mul_int( mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_uint
      * calculating the result is trivial in those cases. */
     if( b == 0 || n == 0 )
     {
-        mbedtls_mpi_lset( X, 0 );
-        return( 0 );
+        return mbedtls_mpi_lset( X, 0 );
     }
 
     /* Calculate A*b as A + A*(b-1) to take advantage of mpi_mul_hlp */