Remove last use of non-bit operations
According to https://www.bearssl.org/ctmul.html even single-precision
multiplication is not constant-time on some older platforms.
An added benefit of the new code is that it removes the somewhat mysterious
constant 0x1ff - which was selected because at that point the maximum value of
padlen was 256. The new code is perhaps a bit more readable for that reason.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 6091834..e5def64 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -1679,7 +1679,7 @@
if( padlen > 0 && correct == 0 )
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad padding byte detected" ) );
#endif
- padlen &= correct * 0x1FF;
+ padlen &= mbedtls_ssl_cf_mask_from_bit( correct );
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
