From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1025519-1521802485-2-6292106131538215999 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=1521802485; b=QUYrCgARWVLPQeMq+kSMov/UVqOMOEDEl+EgNiI3Mj9jZrd wI1/j6XFCCNzCSnKnyNwF6hhIwnZUWCIfyrZjT9Xt22uYrUJ65q8Q9r1Z1MHpydF FKZy1D2V1r/qcocBApiH+3CfqsPxNbhNbJrd0IXg8cmmjHvBlDR+tlgaq1aUdYEv 6hEtG24hsd04Qv8VifP8q5Eb+T4Q3KEou6i+4imLynnlx7gTnvnjP+17wfExD/oW +Bpfou+VfPLsqrCvqBYIpuhAhWM0iysNZGrIeosju96gaTil49mnbH5DYPxElLlc SfUs8jf82MjECkSqrVvtw7xbMfvlKg8SvZZZLcQ== 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=1521802485; bh=ALjsDzKmvOKYRsFsNX+Gm6Rn9Y leBzaF6iaJKr56b+M=; b=Lm6j328ApWPTWdcap6aZFSXPoNzR3qSv7BLT7u818o FjoMkQqrm1eht0hWIKT1ZQWz+v3WvYTvw/AIaX9xF0YmWg+HTlg43N2vDh/q26p9 W45alC5C/2pXrMK1NLL83Y/K/wEh5FjXK1lA1Yjur2qhidMThHtW+abC67WrVjQk oiH2iigYGRzYuHfwsONF9cHkwEm6/uetDetgJJ+dBFFQ3aI0McpYGDYx9H8h763C ezFE8dhvrC20ydzvCcsR9UofHaTXKjGjH85izUCgaOfTmLM24Pi53qKbYtxR08Ua uO2w99zDn6t2OO/7lmQmcwdyjRcYJhDJL7UpisPuqE2A== 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=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: 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=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 S1755875AbeCWKNa (ORCPT ); Fri, 23 Mar 2018 06:13:30 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:44816 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755860AbeCWKN2 (ORCPT ); Fri, 23 Mar 2018 06:13:28 -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 4.4 05/97] staging: android: ashmem: Fix possible deadlock in ashmem_ioctl Date: Fri, 23 Mar 2018 10:53:52 +0100 Message-Id: <20180323094157.843632674@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180323094157.535925724@linuxfoundation.org> References: <20180323094157.535925724@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: 4.4-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 @@ -703,16 +703,14 @@ 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;