From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D6711C433F1 for ; Mon, 27 Jul 2020 17:03:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B3CEA2078A for ; Mon, 27 Jul 2020 17:03:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="RYz1YCi4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729230AbgG0RDH (ORCPT ); Mon, 27 Jul 2020 13:03:07 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:39514 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728999AbgG0RDH (ORCPT ); Mon, 27 Jul 2020 13:03:07 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06RH1m1l115287; Mon, 27 Jul 2020 17:02:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=TeNtDqDqIQ7vUEFJe8evTe6FYY6zKZvMIc3ENnPMQc0=; b=RYz1YCi4flsp2nsaalElHjr/hSEq9BFy53s+1DZ+5n+d1AvmCPHXu6sh5Y145WTuFAai HU0TACE1RDbQRpWN8Z8XTQB98axZVsYGs7DSYIoz/h7Klai8PAGqwKRTLDbKImfMts3S P+PsgiBo0fou1y6SAFN9Hpuk/GMdlLoiKrPK69KDT+4x6bJ2UE1bkWLpW+GLclUvh5Dw uGR1Dpzy+80qdnAlIFuEp6v4lk8LH6FusYE8y+/sTrhAFxKylcskhlPSMXWjNYe0nDFJ H5EbxXytrIkHX1d3qQwm16zuK82R9R5HiCQh7J2V0isgUvT+NIRyX4CtBbCtekUKREkg wQ== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 32hu1j2rah-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 27 Jul 2020 17:02:13 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 06RGgWKE055548; Mon, 27 Jul 2020 17:02:12 GMT Received: from pps.reinject (localhost [127.0.0.1]) by userp3020.oracle.com with ESMTP id 32hu5r9fa8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Mon, 27 Jul 2020 17:02:12 +0000 Received: from userp3020.oracle.com (userp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 06RGuWGh111604; Mon, 27 Jul 2020 17:02:12 GMT Received: from ca-qasparc-x86-2.us.oracle.com (ca-qasparc-x86-2.us.oracle.com [10.147.24.103]) by userp3020.oracle.com with ESMTP id 32hu5r9f7r-3; Mon, 27 Jul 2020 17:02:12 +0000 From: Anthony Yznaga To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: mhocko@kernel.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, gerg@linux-m68k.org, ktkhai@virtuozzo.com, christian.brauner@ubuntu.com, peterz@infradead.org, esyr@redhat.com, jgg@ziepe.ca, christian@kellner.me, areber@redhat.com, cyphar@cyphar.com, steven.sistare@oracle.com Subject: [RFC PATCH 2/5] mm: do not assume only the stack vma exists in setup_arg_pages() Date: Mon, 27 Jul 2020 10:11:24 -0700 Message-Id: <1595869887-23307-3-git-send-email-anthony.yznaga@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> References: <1595869887-23307-1-git-send-email-anthony.yznaga@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9695 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 bulkscore=0 mlxlogscore=999 lowpriorityscore=0 malwarescore=0 clxscore=1015 mlxscore=0 impostorscore=0 phishscore=0 adultscore=0 suspectscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007270117 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In preparation for allowing vmas to be preserved across exec do not assume that there is no prev vma to pass to mprotect_fixup() in setup_arg_pages(). Also, setup_arg_pages() expands the initial stack of a process by 128k or to the stack size limit, whichever is smaller. expand_stack() assumes there is no vma between the vma passed to it and the address to expand to, so check before calling it. Signed-off-by: Anthony Yznaga --- fs/exec.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/exec.c b/fs/exec.c index e6e8a9a70327..262112e5f9f8 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -720,7 +720,7 @@ int setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_shift; struct mm_struct *mm = current->mm; struct vm_area_struct *vma = bprm->vma; - struct vm_area_struct *prev = NULL; + struct vm_area_struct *prev = vma->vm_prev; unsigned long vm_flags; unsigned long stack_base; unsigned long stack_size; @@ -819,6 +819,10 @@ int setup_arg_pages(struct linux_binprm *bprm, else stack_base = vma->vm_start - stack_expand; #endif + if (vma != find_vma(mm, stack_base)) { + ret = -EFAULT; + goto out_unlock; + } current->mm->start_stack = bprm->p; ret = expand_stack(vma, stack_base); if (ret) -- 1.8.3.1