From patchwork Tue Apr 14 15:01:08 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 11487979 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7B21814DD for ; Tue, 14 Apr 2020 15:01:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 60B7020787 for ; Tue, 14 Apr 2020 15:01:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Thn6i5Nl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405517AbgDNPBZ (ORCPT ); Tue, 14 Apr 2020 11:01:25 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:55678 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2405178AbgDNPBU (ORCPT ); Tue, 14 Apr 2020 11:01:20 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1586876479; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=BNJ2ShHeuV6cRZ6cvuASvIdGYqCK2PoGgkFRTICHqX4=; b=Thn6i5NlU3C5yhNgG2Df5SZCT611+IK5Q+pepsfEBcmyMgU6SITyP3qCwppTQpXA1G7cqq GTXSNLh8OyMiclmQ3blVs0YFn4k+VRJD0l+oLVYsmYHBK5H8sHIJNuyf6amEnCUjsis41l DCgb2IznFQ1/q5EvEPuhrTijorbHV1U= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-441-kQ2e62LZMdOYkQ8zuUBLYg-1; Tue, 14 Apr 2020 11:01:11 -0400 X-MC-Unique: kQ2e62LZMdOYkQ8zuUBLYg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4997E149C0; Tue, 14 Apr 2020 15:01:10 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-113-129.rdu2.redhat.com [10.10.113.129]) by smtp.corp.redhat.com (Postfix) with ESMTP id 71B7B126510; Tue, 14 Apr 2020 15:01:09 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Jarkko Sakkinen cc: dhowells@redhat.com, vvs@virtuozzo.com, keyrings@vger.kernel.org Subject: [PATCH] keys: Fix proc_keys_next to increase position index MIME-Version: 1.0 Content-ID: <3881683.1586876468.1@warthog.procyon.org.uk> Date: Tue, 14 Apr 2020 16:01:08 +0100 Message-ID: <3881684.1586876468@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: keyrings-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org Hi Jarkko, I'm planning on passing this on to Linus if you're okay with it. Note that I've altered the subject and the body slightly. David --- commit 3e87bc31455f887a0372276990249a150e31fc5a Author: Vasily Averin Date: Thu Jan 30 13:16:27 2020 +0300 keys: Fix proc_keys_next to increase position index 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 $ dd if=/proc/keys bs=500 skip=1 # read after lseek in middle of last line dd: /proc/keys: cannot skip to specified offset g _uid_ses.1000: 1 <<<< end of last line 3ead4096 I--Q--- 1 perm 1f3f0000 1000 65534 keyring _uid_ses.1000: 1 <<<< and whole last line again 0+1 records in 0+1 records out 97 bytes copied, 0,000135035 s, 718 kB/s $ 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 <<<< generates last line 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 Cc: stable@vger.kernel.org Fixes: 1f4aace60b0e ("fs/seq_file.c: simplify seq_file iteration code ...") Signed-off-by: Vasily Averin Signed-off-by: David Howells diff --git a/security/keys/proc.c b/security/keys/proc.c index 415f3f1c2da0..d0cde6685627 100644 --- a/security/keys/proc.c +++ b/security/keys/proc.c @@ -139,6 +139,8 @@ static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos) n = key_serial_next(p, v); if (n) *_pos = key_node_serial(n); + else + (*_pos)++; return n; }