Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752397AbbLEVdQ (ORCPT ); Sat, 5 Dec 2015 16:33:16 -0500 Received: from mail-lf0-f42.google.com ([209.85.215.42]:35431 "EHLO mail-lf0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751379AbbLEVdP (ORCPT ); Sat, 5 Dec 2015 16:33:15 -0500 From: Rasmus Villemoes To: Ursula Braun , Martin Schwidefsky , Heiko Carstens Cc: Rasmus Villemoes , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] qeth: don't rely on signedness of char Date: Sat, 5 Dec 2015 22:32:52 +0100 Message-Id: <1449351173-6915-1-git-send-email-linux@rasmusvillemoes.dk> X-Mailer: git-send-email 2.6.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1544 Lines: 41 AFAICT, char is unsigned on s390. Relying on that is a little subtle. The problem here is that if char happens to be signed and e.g. card->info.mcl_level[2] contains the value -16, the formatted output will be "fffffff0", thus overflowing card->info.mcl_level (which has size 5). To help future readers, simply do an explicit mask so that the value passed to sprintf is in 0-255. If char is indeed unsigned, gcc should be able to elide the masking. In any case, the subsequent 0-termination is redundant, since sprintf has done that. Signed-off-by: Rasmus Villemoes --- drivers/s390/net/qeth_core_main.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c index 31ac53fa5cee..84bc4b862fbb 100644 --- a/drivers/s390/net/qeth_core_main.c +++ b/drivers/s390/net/qeth_core_main.c @@ -2682,10 +2682,8 @@ void qeth_print_status_message(struct qeth_card *card) * */ if (!card->info.mcl_level[0]) { sprintf(card->info.mcl_level, "%02x%02x", - card->info.mcl_level[2], - card->info.mcl_level[3]); - - card->info.mcl_level[QETH_MCL_LENGTH] = 0; + card->info.mcl_level[2] & 0xff, + card->info.mcl_level[3] & 0xff); break; } /* fallthrough */ -- 2.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/