From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755217AbdCTN6X (ORCPT ); Mon, 20 Mar 2017 09:58:23 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:34957 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755012AbdCTN6N (ORCPT ); Mon, 20 Mar 2017 09:58:13 -0400 From: Colin King To: Mark Brown , linux-spi@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] spi: loopback-test: fix potential integer overflow on multiple Date: Mon, 20 Mar 2017 13:58:05 +0000 Message-Id: <20170320135805.10182-1-colin.king@canonical.com> X-Mailer: git-send-email 2.11.0 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 A multiplication of 8U * xfer-len with the type of a 32 bit unsigned int is evaluated using 32 bit arithmetic and then used in a context that expects an expression of type unsigned long long (64 bits). Avoid any potential overflow by casting BITS_PER_BYTE to unsigned long long. Detected by CoverityScan, CID#1419691 ("Unintentional integer overflow") Fixes: ea9936f324356 ("spi: loopback-test: add elapsed time check") Signed-off-by: Colin Ian King --- drivers/spi/spi-loopback-test.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-loopback-test.c b/drivers/spi/spi-loopback-test.c index 0d0739142cd3..51c0ceab04cc 100644 --- a/drivers/spi/spi-loopback-test.c +++ b/drivers/spi/spi-loopback-test.c @@ -521,7 +521,8 @@ static int spi_test_check_elapsed_time(struct spi_device *spi, for (i = 0; i < test->transfer_count; i++) { struct spi_transfer *xfer = test->transfers + i; - unsigned long long nbits = BITS_PER_BYTE * xfer->len; + unsigned long long nbits = (unsigned long long)BITS_PER_BYTE * + xfer->len; delay_usecs += xfer->delay_usecs; if (!xfer->speed_hz) -- 2.11.0