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=-4.0 required=3.0 tests=BAYES_00,FROM_LOCAL_HEX, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C54E8C433E0 for ; Wed, 12 Aug 2020 21:28:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9910E2076B for ; Wed, 12 Aug 2020 21:28:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726542AbgHLV2Q (ORCPT ); Wed, 12 Aug 2020 17:28:16 -0400 Received: from mail-il1-f197.google.com ([209.85.166.197]:39015 "EHLO mail-il1-f197.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726508AbgHLV2P (ORCPT ); Wed, 12 Aug 2020 17:28:15 -0400 Received: by mail-il1-f197.google.com with SMTP id i66so2763247ile.6 for ; Wed, 12 Aug 2020 14:28:14 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:date:in-reply-to:message-id:subject :from:to; bh=ilCTY64RuUG02GFuuWjDIx1Ci3e/PJFPZPYdOkrJo64=; b=gPalZwtZkjLXy1VB5dXvwxgJ2DtGKlTKY86fjeMedTKk2DBWuwJSbFbfeSaz+32bfZ LXXCqXAkmdAw2f+rur9xM+aar794CL4lorT1rO9Ww/mR71w1WmDK0HdDTOSffx1GhI+s 7qHZ9+o5Rq6g18RxwNhiotJsQnNnbP+wERG+nIoWlJgGkNs0cx+0ATilmBctmg1W5un3 KlnK9wZoRsNvlIkzrnwJXzfQQkISLqneXgP7mWS4/VuSiEwi9lu1J/eE7tLQ1bbS+8Rm +cHyyGCW8NTaDq5+4BxU5YEL5I3cfErztEYU9hfHG2rjhYWys14zMR2Ztjj0LZ5J6D1C qAtQ== X-Gm-Message-State: AOAM5336m/w2QzJanxlJxhEKtGMzoO/8LZyjrIyKSSo/AYN9+o4IgcLM KC0R5CObOrPYti/chN9B7+U53WVg1ZlIr8BDd2N4v6Hoye5v X-Google-Smtp-Source: ABdhPJw33yFNC2zXSn+p5lX5ZDyAPSvDLXh/be+FiUata4vDh7uXDJLRiUIDIPGB5q7w3Dy5crJD3YjdBt0+8CgnWYplEalN/W0s MIME-Version: 1.0 X-Received: by 2002:a92:aa4b:: with SMTP id j72mr1651939ili.141.1597267694581; Wed, 12 Aug 2020 14:28:14 -0700 (PDT) Date: Wed, 12 Aug 2020 14:28:14 -0700 In-Reply-To: <000000000000f0724405aca59f64@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000008bfef305acb4ddee@google.com> Subject: Re: KASAN: use-after-free Read in path_init (2) From: syzbot To: arnd@arndb.de, christian.brauner@ubuntu.com, hch@lst.de, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux@dominikbrodowski.net, syzkaller-bugs@googlegroups.com, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org syzbot has found a reproducer for the following issue on: HEAD commit: fb893de3 Merge tag 'tag-chrome-platform-for-v5.9' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16139be2900000 kernel config: https://syzkaller.appspot.com/x/.config?x=f1fedc63022bf07e dashboard link: https://syzkaller.appspot.com/bug?extid=bbeb1c88016c7db4aa24 compiler: gcc (GCC) 10.1.0-syz 20200507 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15fa83e2900000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15920c4a900000 The issue was bisected to: commit e24ab0ef689de43649327f54cd1088f3dad25bb3 Author: Christoph Hellwig Date: Tue Jul 21 08:48:15 2020 +0000 fs: push the getname from do_rmdir into the callers bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=155f36c2900000 final oops: https://syzkaller.appspot.com/x/report.txt?x=175f36c2900000 console output: https://syzkaller.appspot.com/x/log.txt?x=135f36c2900000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+bbeb1c88016c7db4aa24@syzkaller.appspotmail.com Fixes: e24ab0ef689d ("fs: push the getname from do_rmdir into the callers") ================================================================== BUG: KASAN: use-after-free in path_init+0x116b/0x13c0 fs/namei.c:2207 Read of size 8 at addr ffff8880950a8a80 by task syz-executor167/6821 CPU: 0 PID: 6821 Comm: syz-executor167 Not tainted 5.8.0-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 path_init+0x116b/0x13c0 fs/namei.c:2207 path_parentat+0x22/0x1b0 fs/namei.c:2384 filename_parentat+0x188/0x560 fs/namei.c:2407 do_rmdir+0xa8/0x440 fs/namei.c:3732 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4403e9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 7b 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffd4e3bdb58 EFLAGS: 00000246 ORIG_RAX: 0000000000000054 RAX: ffffffffffffffda RBX: 69662f7375622f2e RCX: 00000000004403e9 RDX: 00000000004403e9 RSI: 00000000004403e9 RDI: 0000000020000080 RBP: 2f31656c69662f2e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401bf0 R13: 0000000000401c80 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 6821: 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 getname_flags.part.0+0x50/0x4f0 fs/namei.c:138 getname_flags include/linux/audit.h:320 [inline] getname fs/namei.c:209 [inline] __do_sys_rmdir fs/namei.c:3783 [inline] __se_sys_rmdir fs/namei.c:3781 [inline] __x64_sys_rmdir+0xb1/0x100 fs/namei.c:3781 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6821: 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 putname+0xe1/0x120 fs/namei.c:259 do_rmdir+0x145/0x440 fs/namei.c:3773 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880950a8a80 which belongs to the cache names_cache of size 4096 The buggy address is located 0 bytes inside of 4096-byte region [ffff8880950a8a80, ffff8880950a9a80) The buggy address belongs to the page: page:00000000c8532513 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x950a8 head:00000000c8532513 order:1 compound_mapcount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea0002540e88 ffffea000251ef88 ffff88821bc47a00 raw: 0000000000000000 ffff8880950a8a80 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880950a8980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff8880950a8a00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8880950a8a80: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880950a8b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880950a8b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================