From bb66dac9717682795486898ed986a1151ca7ce64 Mon Sep 17 00:00:00 2001 From: Gilles Peskine Date: Thu, 13 May 2021 00:00:45 +0200 Subject: [PATCH] Fix spurious -Wstringop-overflow with GCC 11.1 A previous fix in d596ca8a1e34b6ef2fda293250829d014e5d33af worked with beta versions of GCC 11, but not with the final 11.1 release. This time, just disable the warning locally. Fix #4130 Signed-off-by: Gilles Peskine --- library/ssl_tls.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/library/ssl_tls.c b/library/ssl_tls.c index e367fbd9c..133b2c2ee 100644 --- a/library/ssl_tls.c +++ b/library/ssl_tls.c @@ -3265,8 +3265,6 @@ static void ssl_calc_finished_tls_sha256( #if defined(MBEDTLS_SHA512_C) -typedef int (*finish_sha384_t)(mbedtls_sha512_context*, unsigned char*); - static void ssl_calc_finished_tls_sha384( mbedtls_ssl_context *ssl, unsigned char *buf, int from ) { @@ -3325,13 +3323,19 @@ static void ssl_calc_finished_tls_sha384( MBEDTLS_SSL_DEBUG_BUF( 4, "finished sha512 state", (unsigned char *) sha512.state, sizeof( sha512.state ) ); #endif - /* - * 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(). + /* mbedtls_sha512_finish_ret's output parameter is declared as a + * 64-byte buffer, but sice we're using SHA-384, we know that the + * output fits in 48 bytes. This is correct C, but GCC 11.1 warns + * about it. */ - finish_sha384_t finish = (finish_sha384_t)mbedtls_sha512_finish_ret; - finish( &sha512, padbuf ); +#if defined(__GNUC__) && __GNUC__ >= 11 +#pragma GCC diagnostic push +#pragma GCC diagnostic ignored "-Wstringop-overflow" +#endif + mbedtls_sha512_finish_ret( &sha512, padbuf ); +#if defined(__GNUC__) && __GNUC__ >= 11 +#pragma GCC diagnostic pop +#endif mbedtls_sha512_free( &sha512 ); #endif