Fix mpi_bigendian_to_host() on bigendian systems
The previous implementation of mpi_bigendian_to_host() did
a byte-swapping regardless of the endianness of the system.
Fixes #2622.
diff --git a/library/bignum.c b/library/bignum.c
index 4194618..a1822fc 100644
--- a/library/bignum.c
+++ b/library/bignum.c
@@ -742,10 +742,15 @@
static mbedtls_mpi_uint mpi_uint_bigendian_to_host_c( mbedtls_mpi_uint x )
{
uint8_t i;
+ unsigned char *x_ptr;
mbedtls_mpi_uint tmp = 0;
- /* This works regardless of the endianness. */
- for( i = 0; i < ciL; i++, x >>= 8 )
- tmp |= ( x & 0xFF ) << ( ( ciL - 1 - i ) << 3 );
+
+ for( i = 0, x_ptr = (unsigned char*) &x; i < ciL; i++, x_ptr++ )
+ {
+ tmp <<= CHAR_BIT;
+ tmp |= (mbedtls_mpi_uint) *x_ptr;
+ }
+
return( tmp );
}