From patchwork Mon Apr 20 12:39:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 227459 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, 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 E9C4BC3815B for ; Mon, 20 Apr 2020 12:47:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CC0492078E for ; Mon, 20 Apr 2020 12:47:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587386833; bh=HaUo+E5NxLGCGdFw4NKrqAONKCA3eOeOzeVolfXxgx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=dAzP998YSBzdLIt+dCk0PzsSKAId0RIljITqCg/RXnCMOJljWNFCSLQ4oxw+6MOhP lsGgDjTrDMV2yoxMOkkAjgjRGO25Fom4sih7dcqI6OtFxdodQevt35ZoQYInfUarFh ahZXa1FHVBwOCcmkdICGLJzGm/ss4Cds/NbBd6vg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729043AbgDTMrN (ORCPT ); Mon, 20 Apr 2020 08:47:13 -0400 Received: from mail.kernel.org ([198.145.29.99]:43040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729039AbgDTMrM (ORCPT ); Mon, 20 Apr 2020 08:47:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 A67F4206DD; Mon, 20 Apr 2020 12:47:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587386831; bh=HaUo+E5NxLGCGdFw4NKrqAONKCA3eOeOzeVolfXxgx4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CcFhuSVb+ksShl3JkuC+WsYq0aJWNJmPPHaQAiaIAI8jFF0lqPWSyyMb8JDb9JbuO xocPU3Gwl7v6PpfmWdMfvz5UUDm55OYRKf4Oo9bKwQyIU/B5Wyz0KKsLTa9RnOy+E/ YYKFQhkrY9Fkb1pXXzCBhpLDtYmHAeWxekoYmimw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vasily Averin , David Howells , Jarkko Sakkinen , Linus Torvalds Subject: [PATCH 5.4 42/60] keys: Fix proc_keys_next to increase position index Date: Mon, 20 Apr 2020 14:39:20 +0200 Message-Id: <20200420121512.118553683@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200420121500.490651540@linuxfoundation.org> References: <20200420121500.490651540@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Vasily Averin commit 86d32f9a7c54ad74f4514d7fef7c847883207291 upstream. If seq_file .next function does not change position index, read after some lseek can generate unexpected output: $ dd if=/proc/keys bs=1 # full usual output 0f6bfdf5 I--Q--- 2 perm 3f010000 1000 1000 user 4af2f79ab8848d0a: 740 1fb91b32 I--Q--- 3 perm 1f3f0000 1000 65534 keyring _uid.1000: 2 27589480 I--Q--- 1 perm 0b0b0000 0 0 user invocation_id: 16 2f33ab67 I--Q--- 152 perm 3f030000 0 0 keyring _ses: 2 33f1d8fa I--Q--- 4 perm 3f030000 1000 1000 keyring _ses: 1 3d427fda I--Q--- 2 perm 3f010000 1000 1000 user 69ec44aec7678e5a: 740 3ead4096 I--Q--- 1 perm 1f3f0000 1000 65534 keyring _uid_ses.1000: 1 521+0 records in 521+0 records out 521 bytes copied, 0,00123769 s, 421 kB/s But a read after lseek in middle of last line results in the partial last line and then a repeat of the final line: $ dd if=/proc/keys bs=500 skip=1 dd: /proc/keys: cannot skip to specified offset g _uid_ses.1000: 1 3ead4096 I--Q--- 1 perm 1f3f0000 1000 65534 keyring _uid_ses.1000: 1 0+1 records in 0+1 records out 97 bytes copied, 0,000135035 s, 718 kB/s and a read after lseek beyond end of file results in the last line being shown: $ dd if=/proc/keys bs=1000 skip=1 # read after lseek beyond end of file dd: /proc/keys: cannot skip to specified offset 3ead4096 I--Q--- 1 perm 1f3f0000 1000 65534 keyring _uid_ses.1000: 1 0+1 records in 0+1 records out 76 bytes copied, 0,000119981 s, 633 kB/s See https://bugzilla.kernel.org/show_bug.cgi?id=206283 Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...") Signed-off-by: Vasily Averin Signed-off-by: David Howells Reviewed-by: Jarkko Sakkinen Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- security/keys/proc.c | 2 ++ 1 file changed, 2 insertions(+) --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -139,6 +139,8 @@ static void *proc_keys_next(struct seq_f n = key_serial_next(p, v); if (n) *_pos = key_node_serial(n); + else + (*_pos)++; return n; }