Remove a kludge for the output size of mbedtls_sha512_finish_ret

Remove a kludge to avoid a warning in GCC 11 when calling
mbedtls_sha512_finish_ret with a 48-byte output buffer. This is correct
since we're calculating SHA-384. When mbedtls_sha512_finish_ret's output
parameter was declared as a 64-byte array, GCC 11 -Wstringop-overflow
emitted a well-meaning, but inaccurate buffer overflow warning, which we
tried to work around (successfully with beta releases but unsuccessfully
with GCC 11.1.0 as released). Now that the output parameter is declared as a
pointer, no workaround is necessary.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
This commit is contained in:
Gilles Peskine 2021-05-13 00:26:17 +02:00
parent e02e02f203
commit 3e3a6789d1

View file

@ -2897,8 +2897,6 @@ static void ssl_calc_finished_tls_sha256(
#if defined(MBEDTLS_SHA512_C) #if defined(MBEDTLS_SHA512_C)
typedef int (*finish_sha384_t)(mbedtls_sha512_context*, unsigned char*);
static void ssl_calc_finished_tls_sha384( static void ssl_calc_finished_tls_sha384(
mbedtls_ssl_context *ssl, unsigned char *buf, int from ) mbedtls_ssl_context *ssl, unsigned char *buf, int from )
{ {
@ -2957,13 +2955,7 @@ static void ssl_calc_finished_tls_sha384(
MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *) MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *)
sha512.state, sizeof( sha512.state ) ); sha512.state, sizeof( sha512.state ) );
#endif #endif
/* mbedtls_sha512_finish_ret( &sha512, padbuf );
* For SHA-384, we can save 16 bytes by keeping padbuf 48 bytes long.
* However, to avoid stringop-overflow warning in gcc, we have to cast
* mbedtls_sha512_finish_ret().
*/
finish_sha384_t finish = (finish_sha384_t)mbedtls_sha512_finish_ret;
finish( &sha512, padbuf );
mbedtls_sha512_free( &sha512 ); mbedtls_sha512_free( &sha512 );
#endif #endif