From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 404C6ECE587 for ; Mon, 14 Oct 2019 13:16:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F7552089C for ; Mon, 14 Oct 2019 13:16:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731517AbfJNNQN (ORCPT ); Mon, 14 Oct 2019 09:16:13 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:38785 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727789AbfJNNQM (ORCPT ); Mon, 14 Oct 2019 09:16:12 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1iK0Cn-0005Vt-14; Mon, 14 Oct 2019 13:16:09 +0000 From: Colin King To: Jaroslav Kysela , "Rafael J . Wysocki" Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] PNP: fix unintended sign extension on left shifts Date: Mon, 14 Oct 2019 14:16:08 +0100 Message-Id: <20191014131608.31335-1-colin.king@canonical.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Ian King Shifting a u8 left will cause the value to be promoted to an integer. If the top bit of the u8 is set then the following conversion to a 64 bit resource_size_t will sign extend the value causing the upper 32 bits to be set in the result. Fix this by casting the u8 value to a resource_size_t before the shift. Original commit is pre-git history. Signed-off-by: Colin Ian King --- drivers/pnp/isapnp/core.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/drivers/pnp/isapnp/core.c b/drivers/pnp/isapnp/core.c index 179b737280e1..c947b1673041 100644 --- a/drivers/pnp/isapnp/core.c +++ b/drivers/pnp/isapnp/core.c @@ -511,10 +511,14 @@ static void __init isapnp_parse_mem32_resource(struct pnp_dev *dev, unsigned char flags; isapnp_peek(tmp, size); - min = (tmp[4] << 24) | (tmp[3] << 16) | (tmp[2] << 8) | tmp[1]; - max = (tmp[8] << 24) | (tmp[7] << 16) | (tmp[6] << 8) | tmp[5]; - align = (tmp[12] << 24) | (tmp[11] << 16) | (tmp[10] << 8) | tmp[9]; - len = (tmp[16] << 24) | (tmp[15] << 16) | (tmp[14] << 8) | tmp[13]; + min = ((resource_size_t)tmp[4] << 24) | (tmp[3] << 16) | + (tmp[2] << 8) | tmp[1]; + max = ((resource_size_t)tmp[8] << 24) | (tmp[7] << 16) | + (tmp[6] << 8) | tmp[5]; + align = ((resource_size_t)tmp[12] << 24) | (tmp[11] << 16) | + (tmp[10] << 8) | tmp[9]; + len = ((resource_size_t)tmp[16] << 24) | (tmp[15] << 16) | + (tmp[14] << 8) | tmp[13]; flags = tmp[0]; pnp_register_mem_resource(dev, option_flags, min, max, align, len, flags); @@ -532,8 +536,10 @@ static void __init isapnp_parse_fixed_mem32_resource(struct pnp_dev *dev, unsigned char flags; isapnp_peek(tmp, size); - base = (tmp[4] << 24) | (tmp[3] << 16) | (tmp[2] << 8) | tmp[1]; - len = (tmp[8] << 24) | (tmp[7] << 16) | (tmp[6] << 8) | tmp[5]; + base = ((resource_size_t)tmp[4] << 24) | (tmp[3] << 16) | + (tmp[2] << 8) | tmp[1]; + len = ((resource_size_t)tmp[8] << 24) | (tmp[7] << 16) | + (tmp[6] << 8) | tmp[5]; flags = tmp[0]; pnp_register_mem_resource(dev, option_flags, base, base, 0, len, flags); } -- 2.20.1