Remove dead preprocessor code

There's no way currently (see below regarding the future) that ECC-based
key exchanges are enabled without ECP_C being defined. So, the #if was
fully redundant with the checks surrounding the function, as it always
evaluated to true.

The situation arose as, in the old days (before Mbed TLS 2.0),
mbedtls_ssl_conf_curves() (or ssl_set_curves() as it was called back
then) was optional, controlled by its own compile-time option
POLARSSL_SSL_SET_CURVES. So, in turn mbedtls_ssl_check_curve() depended
on POLARSSL_SSL_SET_CURVES too, and all calls to it were guarded by
that.

When it was made non-optional, a blind
s/POLARSSL_SSL_SET_CURVES/MBEDTLS_ECP_C/ was done, which resulted in
stupid situations like this with redundant checks for ECP_C.

Note regarding the future: at some point it will be possible to compile
with ECC-based key exchanges but without ECP_C. This doesn't change
anything to the reasoning above: mbedtls_ssl_check_curve() will be
available in all builds where ECC is used; it will just need a new
definition (with new guards), but that doesn't change anything for its
callers.

Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
This commit is contained in:
Manuel Pégourié-Gonnard 2022-01-18 12:41:48 +01:00
parent 4a0ac1f160
commit 3caa0edb9b

View file

@ -2334,12 +2334,7 @@ static int ssl_check_server_ecdh_params( const mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 2, ( "ECDH curve: %s", curve_info->name ) );
#if defined(MBEDTLS_ECP_C)
if( mbedtls_ssl_check_curve( ssl, grp_id ) != 0 )
#else
if( ssl->handshake->ecdh_ctx.grp.nbits < 163 ||
ssl->handshake->ecdh_ctx.grp.nbits > 521 )
#endif
return( -1 );
MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,