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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 4D64AC3A589 for ; Tue, 20 Aug 2019 13:46:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E0C922DA9 for ; Tue, 20 Aug 2019 13:46:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308776; bh=QSnNxxMoohRzifLH0u+uYpnq0gUgkQHKqDHmE1Cvx4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2OtgnhocMLzgHDtiry34E0B3Rs075RQ+1zllqydYaoV5SLtlgybK6KvtuNTay72FX V0sGNxLoN90MwBGR2P9YyNEQbibVCbjSoXERftxfUPstYIRCKuB4HpFOl9Rf0vucUf gwQjGJ0WMtxXmVENCdk+bXS0K2dkQdRHCL7kvXb8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730579AbfHTNmT (ORCPT ); Tue, 20 Aug 2019 09:42:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:37596 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729956AbfHTNmT (ORCPT ); Tue, 20 Aug 2019 09:42:19 -0400 Received: from sasha-vm.mshome.net (unknown [12.236.144.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 03C5422DD6; Tue, 20 Aug 2019 13:42:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1566308538; bh=QSnNxxMoohRzifLH0u+uYpnq0gUgkQHKqDHmE1Cvx4c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Gw6Y8jL731kSFpJycv4r3FgG6kdBAiv4N8nhSOqkE0JkT/kGSDlMLlN79+DwFTRrG AyUR0u4iR8FBDit7C0GJy3oIdJmTSPtrxMWfJAbX5AXu4oAadEEbC6+S+apG+auK2q zmXMXB6lV1iniqbw2dbw9dGHKryR2nWVcMYgNzbk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jia-Ju Bai , David Howells , Sasha Levin , linux-afs@lists.infradead.org Subject: [PATCH AUTOSEL 4.19 05/27] fs: afs: Fix a possible null-pointer dereference in afs_put_read() Date: Tue, 20 Aug 2019 09:41:51 -0400 Message-Id: <20190820134213.11279-5-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190820134213.11279-1-sashal@kernel.org> References: <20190820134213.11279-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jia-Ju Bai [ Upstream commit a6eed4ab5dd4bfb696c1a3f49742b8d1846a66a0 ] In afs_read_dir(), there is an if statement on line 255 to check whether req->pages is NULL: if (!req->pages) goto error; If req->pages is NULL, afs_put_read() on line 337 is executed. In afs_put_read(), req->pages[i] is used on line 195. Thus, a possible null-pointer dereference may occur in this case. To fix this possible bug, an if statement is added in afs_put_read() to check req->pages. This bug is found by a static analysis tool STCheck written by us. Fixes: f3ddee8dc4e2 ("afs: Fix directory handling") Signed-off-by: Jia-Ju Bai Signed-off-by: David Howells Signed-off-by: Sasha Levin --- fs/afs/file.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/fs/afs/file.c b/fs/afs/file.c index 7d4f26198573d..843d3b970b845 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -193,11 +193,13 @@ void afs_put_read(struct afs_read *req) int i; if (refcount_dec_and_test(&req->usage)) { - for (i = 0; i < req->nr_pages; i++) - if (req->pages[i]) - put_page(req->pages[i]); - if (req->pages != req->array) - kfree(req->pages); + if (req->pages) { + for (i = 0; i < req->nr_pages; i++) + if (req->pages[i]) + put_page(req->pages[i]); + if (req->pages != req->array) + kfree(req->pages); + } kfree(req); } } -- 2.20.1