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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 DCEA9C4727F for ; Tue, 29 Sep 2020 12:01:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 81E882074A for ; Tue, 29 Sep 2020 12:01:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601380864; bh=i1ZgjExRvDCjhGcCJkiP8I89j+dferq7go6VHY189IY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jbZATVb29N7tc7KgcjTMExO32feJ5DK3kHzBOFZZjWImaK0wzkwM7FOzrRIxVL/0y gXmkeNKKPLWvpE8BB41vN4LLPqIK9li/FI49/1iymbyPRLEgLIftBkKIkGMLFLjouv 5cWOnBkD1P5kEniVXlLKvRl3DrISf2WTqMcBEavs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731290AbgI2MBD (ORCPT ); Tue, 29 Sep 2020 08:01:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:36830 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730571AbgI2Lku (ORCPT ); Tue, 29 Sep 2020 07:40:50 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3C14723A5D; Tue, 29 Sep 2020 11:23:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378627; bh=i1ZgjExRvDCjhGcCJkiP8I89j+dferq7go6VHY189IY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aoI5z0xdFcE8PW3akf13/z358AKDHC2Jk5ZT29PYDHWfW4DxrCH9uSK88eJ57y2+q 75t1/7oKCDurIQLwmOXUwTm6gv/onr+yJYrJRupT5BCxlRlUsgoixS7tz7PZRVoQ7l FKktzsYBnsJew6ckuwPfDX4raQ6EcIZpmvubzc58= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vasily Averin , Stephen Smalley , Paul Moore , Sasha Levin Subject: [PATCH 4.19 074/245] selinux: sel_avc_get_stat_idx should increase position index Date: Tue, 29 Sep 2020 12:58:45 +0200 Message-Id: <20200929105950.598465758@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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 f3a5a138a096d..60b3f16bb5c7b 100644 --- a/security/selinux/selinuxfs.c +++ b/security/selinux/selinuxfs.c @@ -1509,6 +1509,7 @@ 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