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=-16.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 18AC7C43463 for ; Fri, 18 Sep 2020 02:15:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2B8D238A0 for ; Fri, 18 Sep 2020 02:15:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395350; bh=R0qJl8cpdipNiLHHrTKFMp6DOFeRLJGND6qxED8fQE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rsWN5/4KCEbQKbQ7ZwyRjfuCvMUV8yvk/0czGNHgUVFyWp9A1YuAZSd2PSMWof9CO HVrdYGtBJmYcCNbBlQ9Fj43FNLHqkkjvTo3ISnc8bdbwC1oOVa0regSKU7lVB5zM7l YOM/l2bo0fWFA1SIPPlGNPRwfoBMkJ2efkZoOKPE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729290AbgIRCPt (ORCPT ); Thu, 17 Sep 2020 22:15:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:44648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728540AbgIRCPj (ORCPT ); Thu, 17 Sep 2020 22:15:39 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (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 A6860238A0; Fri, 18 Sep 2020 02:15:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395338; bh=R0qJl8cpdipNiLHHrTKFMp6DOFeRLJGND6qxED8fQE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XbhFUspmtErsytcoLku1vNYaZ4lEf1uoW3gvt5e0dDhZZFbQJVePMVJUiHDXJ/4Lb 3ah+g5vZ2kWfG7Y+OJYrC4GNxag1YKFkQeeYr6xWQF1d6FbrTtWzzmU9l1ibuRHI6y zGlIoCyaYb1l+YVTYsSalfw+OAFrJtRrupXe97x0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Vasily Averin , Stephen Smalley , Paul Moore , Sasha Levin , selinux@tycho.nsa.gov, linux-security-module@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 35/90] selinux: sel_avc_get_stat_idx should increase position index Date: Thu, 17 Sep 2020 22:14:00 -0400 Message-Id: <20200918021455.2067301-35-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021455.2067301-1-sashal@kernel.org> References: <20200918021455.2067301-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Vasily Averin [ Upstream commit 8d269a8e2a8f0bca89022f4ec98de460acb90365 ] If seq_file .next function does not change position index, read after some lseek can generate unexpected output. $ dd if=/sys/fs/selinux/avc/cache_stats # usual output lookups hits misses allocations reclaims frees 817223 810034 7189 7189 6992 7037 1934894 1926896 7998 7998 7632 7683 1322812 1317176 5636 5636 5456 5507 1560571 1551548 9023 9023 9056 9115 0+1 records in 0+1 records out 189 bytes copied, 5,1564e-05 s, 3,7 MB/s $# read after lseek to midle of last line $ dd if=/sys/fs/selinux/avc/cache_stats bs=180 skip=1 dd: /sys/fs/selinux/avc/cache_stats: cannot skip to specified offset 056 9115 <<<< end of last line 1560571 1551548 9023 9023 9056 9115 <<< whole last line once again 0+1 records in 0+1 records out 45 bytes copied, 8,7221e-05 s, 516 kB/s $# read after lseek beyond end of of file $ dd if=/sys/fs/selinux/avc/cache_stats bs=1000 skip=1 dd: /sys/fs/selinux/avc/cache_stats: cannot skip to specified offset 1560571 1551548 9023 9023 9056 9115 <<<< generates whole last line 0+1 records in 0+1 records out 36 bytes copied, 9,0934e-05 s, 396 kB/s https://bugzilla.kernel.org/show_bug.cgi?id=206283 Signed-off-by: Vasily Averin Acked-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Sasha Levin --- security/selinux/selinuxfs.c | 1 + 1 file changed, 1 insertion(+) diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c index 72c145dd799f1..ef1226c1c3add 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1416,6 +1416,7 @@ static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx) *idx = cpu + 1; return &per_cpu(avc_cache_stats, cpu); } + (*idx)++; return NULL; } -- 2.25.1