From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932131AbdL1SMx (ORCPT ); Thu, 28 Dec 2017 13:12:53 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:58899 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754102AbdL1RNT (ORCPT ); Thu, 28 Dec 2017 12:13:19 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Colin Ian King" , "Jonathan Cameron" Date: Thu, 28 Dec 2017 16:59:12 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 34/94] staging: iio: ade7759: fix signed extension bug on shift of a u8 In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2.97-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Colin Ian King commit 13ffe9a26df4e156363579b25c904dd0b1e31bfb upstream. The current shift of st->rx[2] left shifts a u8 24 bits left, promotes the integer to a an int and then to a unsigned u64. If the top bit of st->rx[2] is set then we end up with all the upper bits being set to 1. Fix this by casting st->rx[2] to a u64 before the 24 bit left shift. Detected by CoverityScan CID#144940 ("Unintended sign extension") Fixes: 2919fa54ef64 ("staging: iio: meter: new driver for ADE7759 devices") Signed-off-by: Colin Ian King Signed-off-by: Jonathan Cameron Signed-off-by: Ben Hutchings --- drivers/staging/iio/meter/ade7759.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/staging/iio/meter/ade7759.c +++ b/drivers/staging/iio/meter/ade7759.c @@ -128,7 +128,7 @@ static int ade7759_spi_read_reg_40(struc reg_address); goto error_ret; } - *val = ((u64)st->rx[1] << 32) | (st->rx[2] << 24) | + *val = ((u64)st->rx[1] << 32) | ((u64)st->rx[2] << 24) | (st->rx[3] << 16) | (st->rx[4] << 8) | st->rx[5]; error_ret: