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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 F1FA0C433E1 for ; Fri, 21 Aug 2020 21:48:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CA22E207DA for ; Fri, 21 Aug 2020 21:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598046538; bh=iIaeUgLSgkWB0DZ8zJv3oEjOhq/RVmzyUipTHDfrVSM=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=MXApY1XOQZcF8zzyqY8cDolluZTKxevOEjbFOMrTjnNyXIhJ/0Llku7DOyrOobJqx OyVdpTzuyukPTfRtDvURaIBGqJemL30aHPbAazg6tjyTmwOxQmbNJYoOmcJGbMEfVN WQIVs8v7ildSaf7xMBFp/SDiBg/pjyK/gqjn9UUs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726773AbgHUVs6 (ORCPT ); Fri, 21 Aug 2020 17:48:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:33676 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726187AbgHUVs6 (ORCPT ); Fri, 21 Aug 2020 17:48:58 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1CD09207CD; Fri, 21 Aug 2020 21:48:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598046537; bh=iIaeUgLSgkWB0DZ8zJv3oEjOhq/RVmzyUipTHDfrVSM=; h=Date:From:To:Subject:In-Reply-To:From; b=ul2fK1+GxBERq3edkKfSJ+7hlule6ftoasTdwBxaQ5TTpohe8VtL9ihF2VTOANy9u bFDPRezAz5PJSN7vWViA7Sg21oNEpUqRvZCneHt103VGlhM1viL95TcB/EBEhdJAlW 6Is+PG2PMWRePDQ0UbdTZwUuXYBSC1cBxtxhg9fs= Date: Fri, 21 Aug 2020 14:48:56 -0700 From: Andrew Morton To: jack@suse.cz, mm-commits@vger.kernel.org, shy828301@gmail.com, stable@vger.kernel.org Subject: + mm-madvise-fix-vma-user-after-free.patch added to -mm tree Message-ID: <20200821214856.zMblD0Ajx%akpm@linux-foundation.org> In-Reply-To: <20200820174132.67fd4a7a9359048f807a533b@linux-foundation.org> User-Agent: s-nail v14.8.16 Sender: mm-commits-owner@vger.kernel.org Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: madvise: fix vma user-after-free has been added to the -mm tree. Its filename is mm-madvise-fix-vma-user-after-free.patch This patch should soon appear at https://ozlabs.org/~akpm/mmots/broken-out/mm-madvise-fix-vma-user-after-free.patch and later at https://ozlabs.org/~akpm/mmotm/broken-out/mm-madvise-fix-vma-user-after-free.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Yang Shi Subject: mm: madvise: fix vma user-after-free The syzbot reported the below use-after-free: BUG: KASAN: use-after-free in madvise_willneed mm/madvise.c:293 [inline] BUG: KASAN: use-after-free in madvise_vma mm/madvise.c:942 [inline] BUG: KASAN: use-after-free in do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 Read of size 8 at addr ffff8880a6163eb0 by task syz-executor.0/9996 CPU: 0 PID: 9996 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530 madvise_willneed mm/madvise.c:293 [inline] madvise_vma mm/madvise.c:942 [inline] do_madvise.part.0+0x1c8b/0x1cf0 mm/madvise.c:1145 do_madvise mm/madvise.c:1169 [inline] __do_sys_madvise mm/madvise.c:1171 [inline] __se_sys_madvise mm/madvise.c:1169 [inline] __x64_sys_madvise+0xd9/0x110 mm/madvise.c:1169 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45d4d9 Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f04f7464c78 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 0000000000020800 RCX: 000000000045d4d9 RDX: 0000000000000003 RSI: 0000000000600003 RDI: 0000000020000000 RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec R13: 00007ffc579cce7f R14: 00007f04f74659c0 R15: 000000000118cfec Allocated by task 9992: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461 slab_post_alloc_hook mm/slab.h:518 [inline] slab_alloc mm/slab.c:3312 [inline] kmem_cache_alloc+0x138/0x3a0 mm/slab.c:3482 vm_area_alloc+0x1c/0x110 kernel/fork.c:347 mmap_region+0x8e5/0x1780 mm/mmap.c:1743 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 9992: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kmem_cache_free.part.0+0x67/0x1f0 mm/slab.c:3693 remove_vma+0x132/0x170 mm/mmap.c:184 remove_vma_list mm/mmap.c:2613 [inline] __do_munmap+0x743/0x1170 mm/mmap.c:2869 do_munmap mm/mmap.c:2877 [inline] mmap_region+0x257/0x1780 mm/mmap.c:1716 do_mmap+0xcf9/0x11d0 mm/mmap.c:1545 vm_mmap_pgoff+0x195/0x200 mm/util.c:506 ksys_mmap_pgoff+0x43a/0x560 mm/mmap.c:1596 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 It is because vma is accessed after releasing mmap_lock, but someone else acquired the mmap_lock and the vma is gone. Releasing mmap_lock after accessing vma should fix the problem. Link: https://lkml.kernel.org/r/20200816141204.162624-1-shy828301@gmail.com Fixes: 692fe62433d4c ("mm: Handle MADV_WILLNEED through vfs_fadvise()") Reported-by: syzbot+b90df26038d1d5d85c97@syzkaller.appspotmail.com Signed-off-by: Yang Shi Cc: Jan Kara Cc: [5.4+] Signed-off-by: Andrew Morton --- mm/madvise.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/madvise.c~mm-madvise-fix-vma-user-after-free +++ a/mm/madvise.c @@ -289,9 +289,9 @@ static long madvise_willneed(struct vm_a */ *prev = NULL; /* tell sys_madvise we drop mmap_lock */ get_file(file); - mmap_read_unlock(current->mm); offset = (loff_t)(start - vma->vm_start) + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + mmap_read_unlock(current->mm); vfs_fadvise(file, offset, end - start, POSIX_FADV_WILLNEED); fput(file); mmap_read_lock(current->mm); _ Patches currently in -mm which might be from shy828301@gmail.com are mm-madvise-fix-vma-user-after-free.patch