From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755156AbdLUXvU (ORCPT ); Thu, 21 Dec 2017 18:51:20 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:35450 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752301AbdLUXvR (ORCPT ); Thu, 21 Dec 2017 18:51:17 -0500 From: Colin King To: Vinod Koul , Sanyog Kale , alsa-devel@alsa-project.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][next] soundwire: fix sign extension when shifting buf[2] 24 places Date: Thu, 21 Dec 2017 23:51:13 +0000 Message-Id: <20171221235113.9274-1-colin.king@canonical.com> X-Mailer: git-send-email 2.14.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King The buf[2] left shift by 24 bits is promoted to int (32 bit signed) and then signed-extended to unsigned long long. Hence if the upper bit to buf[2] is set then all the upper bits of addr end up as 1. Fix this by casting it to u64 before shifting it. Also replace the unsigned long long casts to u64 casts to match the same type of addr. Detected by CoverityScan, CID#1463147 ("Unintended sign extension") Fixes: d52d7a1be02c ("soundwire: Add Slave status handling helpers") Signed-off-by: Colin Ian King --- drivers/soundwire/bus.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 4c345197eb55..7211ecc62015 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -522,8 +522,8 @@ static int sdw_program_device_num(struct sdw_bus *bus) * bits to avoid truncation due to size limit. */ addr = buf[5] | (buf[4] << 8) | (buf[3] << 16) | - (buf[2] << 24) | ((unsigned long long)buf[1] << 32) | - ((unsigned long long)buf[0] << 40); + ((u64)buf[2] << 24) | ((u64)buf[1] << 32) | + ((u64)buf[0] << 40); sdw_extract_slave_id(bus, addr, &id); -- 2.14.1