From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1511654-1518325946-2-14556579938648498658 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.001, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='uk', MailFrom='org' X-Spam-charsets: plain='UTF-8' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1518325945; b=F/igbxAKkZ7bOYc8kpGqnknPYjpFJ7W1FKmGTSFa5vdideJ Uo4bTlcz2qIPWfvF0qeAjmr5mKYUzzw/Rk8f8H3mhtCZV5BR7UiVYupRrYU8S9CW roHghlGvx002reQLdR+Tw7tMcb7tC5R0pbCZ6SD4VD++vubXMp4VWQEXTnCH1fHO d+TkxbojnE5rVF9FQId1K8DAcao4lftPK+BNpgbvz51rgPYscM55A+vNUix1knXg GtxvGloL+ByMjqPjfIpwKwz0wkXCgyW8Uba9HtMwTASHitY+gbMxB4kBY5XlF20f vw2DkQpUq647D215meZXzsrkSnH7VV7y2F++1WQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=content-type:content-transfer-encoding :mime-version:from:to:cc:date:message-id:subject:in-reply-to :sender:list-id; s=arctest; t=1518325945; bh=w8ShemzT2ulHYa1MXBO zleI4h3c+NmYh1QYbRXbUl64=; b=iPRuI3wdfcRvqkv7kWEr1d5rWoeIGCbYQbY G6vtVoocuA0ErJWVSraBUrZ6YTJZnFLYZdk6MJGDDaZvpbDYLzrEmvxZW0VVjk/n gFA/psksN+wg3rSgNPxXclOuOMQ8o22S09EXvIkRZ4FFjhZztK53/Ym9ZkZaiod/ w4rI4/o+4DmTiw+8gXJjjpFUSSMU0DvcwXSyDx55YSRQEblDIc0b6NyhRlYpftig byv50VlgOzxMj2xPBaeRO3mI1W/BicQDXnI0lfYxgPPELjzmvusftXzJAG0A0nIc epQdagKoeMOXpAsR3gErAhWukJzhrn0faZ7e24drp2jQfUaF7ew== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=decadent.org.uk; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=decadent.org.uk header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752665AbeBKFMX (ORCPT ); Sun, 11 Feb 2018 00:12:23 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41381 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752602AbeBKEdl (ORCPT ); Sat, 10 Feb 2018 23:33:41 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Al Viro" , "Ian Kent" Date: Sun, 11 Feb 2018 04:20:06 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.2 50/79] autofs4: catatonic_mode vs. notify_daemon race In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 3.2.99-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro commit 8753333266be67ff3a984ac1f6566d31c260bee4 upstream. we need to hold ->wq_mutex while we are forming the packet to send, lest we have autofs4_catatonic_mode() setting wq->name.name to NULL just as autofs4_notify_daemon() decides to memcpy() from it... We do have check for catatonic mode immediately after that (under ->wq_mutex, as it ought to be) and packet won't be actually sent, but it'll be too late for us if we oops on that memcpy() from NULL... Fix is obvious - just extend the area covered by ->wq_mutex over that switch and check whether it's catatonic *before* doing anything else. Acked-by: Ian Kent Signed-off-by: Al Viro Signed-off-by: Ben Hutchings --- fs/autofs4/waitq.c | 25 ++++++++++++++----------- 1 file changed, 14 insertions(+), 11 deletions(-) --- a/fs/autofs4/waitq.c +++ b/fs/autofs4/waitq.c @@ -110,6 +110,13 @@ static void autofs4_notify_daemon(struct pkt.hdr.proto_version = sbi->version; pkt.hdr.type = type; + mutex_lock(&sbi->wq_mutex); + + /* Check if we have become catatonic */ + if (sbi->catatonic) { + mutex_unlock(&sbi->wq_mutex); + return; + } switch (type) { /* Kernel protocol v4 missing and expire packets */ case autofs_ptype_missing: @@ -163,22 +170,18 @@ static void autofs4_notify_daemon(struct } default: printk("autofs4_notify_daemon: bad type %d!\n", type); + mutex_unlock(&sbi->wq_mutex); return; } - /* Check if we have become catatonic */ - mutex_lock(&sbi->wq_mutex); - if (!sbi->catatonic) { - pipe = sbi->pipe; - get_file(pipe); - } + pipe = sbi->pipe; + get_file(pipe); + mutex_unlock(&sbi->wq_mutex); - if (pipe) { - if (autofs4_write(pipe, &pkt, pktsz)) - autofs4_catatonic_mode(sbi); - fput(pipe); - } + if (autofs4_write(pipe, &pkt, pktsz)) + autofs4_catatonic_mode(sbi); + fput(pipe); } static int autofs4_getpath(struct autofs_sb_info *sbi,