From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1182439-1521807445-2-17817066090005728357 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, 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='CN', 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=arctest; t=1521807445; b=TWZ0TcJXVqmDv2lzPK/wujVUToyaPfztEdrD0DjORJcMJs/ 5kGlp9WPepffeYsPLDEfQ1i8e2TihEx5D78n0udcEl/2EQ2u0X/EgWay3Rpj3MF9 FPxT/fbjFIkycg59gLfs8yQZhjMv64hQgg1Jy4gMPIs6fSUxYUg3LdBlr8dDvHNn mvxP/Ik5hfjJbMpN0R5x8r23/RvfKJ6QqfakiMdqie6ey1jGEh2Q3+nnhDoaoAaA G0T2XCHd/lQ3tQMFsYRqJGzjb3ACJ6FCcOjG1szQNXB8Gg3Q5aWia6Vs1X5y2GyK N+7RuOMVmFBumksWl1UAHeX1f3ZEP9MbeKDPaQw== 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=arctest; t=1521807445; bh=SidtmFYYjT0ZscZrcoP4EURt7Y Cr5JtqWfYILWSBif8=; b=vVdGjspFkUPmTAHmMc5w6jWoFKK+ZWq+s99/I3v8PC Lq4F85DpIp5lkXen67qlR4DhImllwVHZ95CMNhwOg3DBTJRwQjR9MNX4/ny75Tlu ddFgMT7qKchnUCfD9DUr85cNutP8jVzmCzGx+YrSAUlhsKdR36u6Mi15dEGA/SvJ oc7WdAaIpnOaNI8ztw+g6JsjmUF+1OmkBl7KpsrToiUHbKHo37LPtNU7j9A85YI2 Y0p9Y+GcN1F1CVGgtGZXZHIhPsCo81kGMyZI4PYqvixDq5Ijn3XWv0OLfYVtUAF3 D+XTy5Pca619jTynE9jq3AgfvrVS3VYF+oqRyVuQuMNg== ARC-Authentication-Results: i=1; mx6.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-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: mx6.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-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 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752365AbeCWJ4S (ORCPT ); Fri, 23 Mar 2018 05:56:18 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:33920 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752305AbeCWJ4Q (ORCPT ); Fri, 23 Mar 2018 05:56:16 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+d7a918a7a8e1c952bc36@syzkaller.appspotmail.com, Yisheng Xie , "Joel Fernandes (Google)" Subject: [PATCH 4.15 02/84] staging: android: ashmem: Fix possible deadlock in ashmem_ioctl Date: Fri, 23 Mar 2018 10:53:16 +0100 Message-Id: <20180323095412.279971390@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323095411.913234798@linuxfoundation.org> References: <20180323095411.913234798@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: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yisheng Xie commit 740a5759bf222332fbb5eda42f89aa25ba38f9b2 upstream. ashmem_mutex may create a chain of dependencies like: CPU0 CPU1 mmap syscall ioctl syscall -> mmap_sem (acquired) -> ashmem_ioctl -> ashmem_mmap -> ashmem_mutex (acquired) -> ashmem_mutex (try to acquire) -> copy_from_user -> mmap_sem (try to acquire) There is a lock odering problem between mmap_sem and ashmem_mutex causing a lockdep splat[1] during a syzcaller test. This patch fixes the problem by move copy_from_user out of ashmem_mutex. [1] https://www.spinics.net/lists/kernel/msg2733200.html Fixes: ce8a3a9e76d0 (staging: android: ashmem: Fix a race condition in pin ioctls) Reported-by: syzbot+d7a918a7a8e1c952bc36@syzkaller.appspotmail.com Signed-off-by: Yisheng Xie Cc: "Joel Fernandes (Google)" Signed-off-by: Greg Kroah-Hartman --- drivers/staging/android/ashmem.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/staging/android/ashmem.c +++ b/drivers/staging/android/ashmem.c @@ -709,16 +709,14 @@ static int ashmem_pin_unpin(struct ashme size_t pgstart, pgend; int ret = -EINVAL; + if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) + return -EFAULT; + mutex_lock(&ashmem_mutex); if (unlikely(!asma->file)) goto out_unlock; - if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) { - ret = -EFAULT; - goto out_unlock; - } - /* per custom, you can pass zero for len to mean "everything onward" */ if (!pin.len) pin.len = PAGE_ALIGN(asma->size) - pin.offset;