From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3269524-1523477719-2-8859717424535748837 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 0.25, MAILING_LIST_MULTI -1, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, 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='org', 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=fm2; t= 1523477718; b=AFJaluZPbbqDwvbbhsvHiMJ4xej0n26JTERdWR1yTRIG0oOg6n 1x+OAfabM7hW7r9zjlKnesczVf0EkAnr8h4mxWJSwLDz2nSpgzEaXYHtyR4FZ9ST yWzGmaRG+wo8Sp7grPquclKNq3hUNYCXOCLtuFyJ49t0IyvZ0ipuHNEzhIdl8pbV VrV3Ldv3lEaoXrLdkcY1gMqaYJcnWG42QB6bHWombua8Bg7MPKwPm3o5ynRrXBNA bFgrUBcSG3iGNFIUDu8vhuYnmG8PPbatTV4L9lSbUrZ6jbYOlmwL2LvIr9BYtCMf gL64+YEWmwB3o7hT8Wa6m8EO98MM01WhULQA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-type:sender :list-id; s=fm2; t=1523477718; bh=zftvxMogSVHAuWnsa6LXC7h6vPQlbA MKE/htGsM8wB4=; b=sHtv/847sr42ZaAceYxCuk9OC0QeQISps34DAtc4H3wqnG sMTORM1Wq4qImO9k+zM9FlEsw6B21nq/O8troUz4jEM9tAc4d3NFZ1smCmyvUQG+ M7PS1ZTEPCv/1AJDtMAlRTJxLCSvMGfG/+rO6zqLZfiiQgNozztF/EHA4fnaREDW EgfbwaDK6bVZ+2btrR11TThfCogI3Biq4pB15PMGYcPm0Haw2QM7FJeYuyqUUS+C Ll/ZRZI8fM+x5kWUY6YddhaZpe5PjejV7bASx7wBicpWhDOzLma+hSNfAqL1Agng DJ3HzyzpRbM/f2EWTDBZ3eEWKJtphpwYfdNSZw1A== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; 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-cm=none score=0; 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=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; 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-cm=none score=0; 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=linuxfoundation.org header.result=pass header_is_org_domain=yes; x-vs=clean score=-100 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfETKWaHd0bnyiHdN1BPFUE1PqxSJp7v1g9QJxa5KmARhufxsQo2U+tP2A6UbHDrrmqu6GKI17mO6QTojLF5aoc6PGzBXkUBE2G7OQK4njkJgoNM0VWii HTkfyZuz52L+zGqElcAQb1VxASreNa+Ii6ZnKBn2+rDKwBagIKshMfuLENiM2pIE28C/zMsp25pCms+lnM00yqeiLRWjEJMw9sIQPL9GdocEVi9NnPk2zOo5 X-CM-Analysis: v=2.3 cv=Tq3Iegfh c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=IkcTkHD0fZMA:10 a=Kd1tUaAdevIA:10 a=TYBLyS7eAAAA:8 a=VwQbUJbxAAAA:8 a=6rqHouBjAAAA:8 a=20KFwNOVAAAA:8 a=cm27Pg_UAAAA:8 a=mK_AVkanAAAA:8 a=drOt6m5kAAAA:8 a=xVhDTqbCAAAA:8 a=PtDNVHqPAAAA:8 a=SOq6UgPBAAAA:8 a=hBqU3vQJAAAA:8 a=Z4Rwk6OoAAAA:8 a=yMhMjlubAAAA:8 a=ag1SF4gXAAAA:8 a=rNsULVQiV86SHlLWsYUA:9 a=HxKWDZkTf5y79ZnT:21 a=BoBft98koqt4epYC:21 a=QEXdDO2ut3YA:10 a=zvYvwCWiE4KgVXXeO06c:22 a=AjGcO6oz07-iQ99wixmX:22 a=Hx1yvPaMooE3kwe23bt7:22 a=xmb-EsYY8bH0VWELuYED:22 a=3gWm3jAn84ENXaBijsEo:22 a=RMMjzBEyIzXRtoq5n5K6:22 a=GrmWmAYt4dzCMttCBZOh:22 a=BpimnaHY1jUKGyF_4-AF:22 a=3hv5r9HjGAh9o5iR9qwG:22 a=WLjMIN4s_96MqnBbPenP:22 a=HkZW87K1Qel5hWWM3VKY:22 a=Yupwre4RP9_Eg_Bd0iYG:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756438AbeDKUPD (ORCPT ); Wed, 11 Apr 2018 16:15:03 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33752 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933264AbeDKSxZ (ORCPT ); Wed, 11 Apr 2018 14:53:25 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kirill Tkhai , Cyrill Gorcunov , Andrei Vagin , Andreas Gruenbacher , Kees Cook , Michael Kerrisk , Al Viro , Oleg Nesterov , Paul Moore , Eric Biederman , Andy Lutomirski , Ingo Molnar , Serge Hallyn , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.9 022/310] pidns: disable pid allocation if pid_ns_prepare_proc() is failed in alloc_pid() Date: Wed, 11 Apr 2018 20:32:41 +0200 Message-Id: <20180411183623.247331431@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180411183622.305902791@linuxfoundation.org> References: <20180411183622.305902791@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 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: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kirill Tkhai [ Upstream commit 8896c23d2ef803f1883fea73117a435925c2b4c4 ] alloc_pidmap() advances pid_namespace::last_pid. When first pid allocation fails, then next created process will have pid 2 and pid_ns_prepare_proc() won't be called. So, pid_namespace::proc_mnt will never be initialized (not to mention that there won't be a child reaper). I saw crash stack of such case on kernel 3.10: BUG: unable to handle kernel NULL pointer dereference at (null) IP: proc_flush_task+0x8f/0x1b0 Call Trace: release_task+0x3f/0x490 wait_consider_task.part.10+0x7ff/0xb00 do_wait+0x11f/0x280 SyS_wait4+0x7d/0x110 We may fix this by restore of last_pid in 0 or by prohibiting of futher allocations. Since there was a similar issue in Oleg Nesterov's commit 314a8ad0f18a ("pidns: fix free_pid() to handle the first fork failure"). and it was fixed via prohibiting allocation, let's follow this way, and do the same. Link: http://lkml.kernel.org/r/149201021004.4863.6762095011554287922.stgit@localhost.localdomain Signed-off-by: Kirill Tkhai Acked-by: Cyrill Gorcunov Cc: Andrei Vagin Cc: Andreas Gruenbacher Cc: Kees Cook Cc: Michael Kerrisk Cc: Al Viro Cc: Oleg Nesterov Cc: Paul Moore Cc: Eric Biederman Cc: Andy Lutomirski Cc: Ingo Molnar Cc: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/pid.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/kernel/pid.c +++ b/kernel/pid.c @@ -322,8 +322,10 @@ struct pid *alloc_pid(struct pid_namespa } if (unlikely(is_child_reaper(pid))) { - if (pid_ns_prepare_proc(ns)) + if (pid_ns_prepare_proc(ns)) { + disable_pid_allocation(ns); goto out_free; + } } get_pid_ns(ns);