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 77A2BC43463 for ; Fri, 18 Sep 2020 02:13:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3F12F23447 for ; Fri, 18 Sep 2020 02:13:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395199; bh=x8jtC8Q1lphuUcKtQz2n3M+Vhekuau3Ukrj1emkaMfk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mbu+l+4iWYZTG989ulznKmygmb7j6Zm7TxzRZFn495tiVzF0YXKMF7r9O8kmmqBAp brX6jqRmkrztxXsHAsGQvm0pJqt6iBEhL1Xkhy7C38RLRPjyLrku0mieTK0B0EpZuT JcrscXzTxk/FQ95Qd0phfYYN1SweYWojQTDEdEu8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728493AbgIRCNS (ORCPT ); Thu, 17 Sep 2020 22:13:18 -0400 Received: from mail.kernel.org ([198.145.29.99]:40176 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727130AbgIRCNN (ORCPT ); Thu, 17 Sep 2020 22:13:13 -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 0B2B32376E; Fri, 18 Sep 2020 02:13:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600395192; bh=x8jtC8Q1lphuUcKtQz2n3M+Vhekuau3Ukrj1emkaMfk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u+EV3DHEtp1ppHHb/JXwxMIB1oV+ollLQp8+5SK3JY0YfCdXaCVsuiCQzp77S3VdM 4sABm8TIZX8Dlh3nnus6jbtZ7vLa7GiGDR+3BOGi7/rlj01EibL7FQqb41k57ohUyH cUzKFYet2OBRHrdHTqDA5r+IIr/f3l/N+DdTQ/JA= 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 4.14 044/127] selinux: sel_avc_get_stat_idx should increase position index Date: Thu, 17 Sep 2020 22:10:57 -0400 Message-Id: <20200918021220.2066485-44-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200918021220.2066485-1-sashal@kernel.org> References: <20200918021220.2066485-1-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 00eed842c491c..bf50fead9f8c0 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1425,6 +1425,7 @@ 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