linux-kernel - KASAN: vmalloc-out-of-bounds Write in lzo

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Date:   Wed, 13 Jan 2021 02:37:16 -0800
From:   syzbot <syzbot+6fba78f99b9afd4b5634@...kaller.appspotmail.com>
To:     akpm@...ux-foundation.org, hch@....de,
        linux-kernel@...r.kernel.org, phillip@...ashfs.org.uk,
        pliard@...gle.com, syzkaller-bugs@...glegroups.com,
        torvalds@...ux-foundation.org
Subject: KASAN: vmalloc-out-of-bounds Write in lzo_uncompress

Hello,

syzbot found the following issue on:

HEAD commit:    a0d54b4f Merge tag 'trace-v5.11-rc2' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11afe9eb500000
kernel config:  https://syzkaller.appspot.com/x/.config?x=c066f800cf2824be
dashboard link: https://syzkaller.appspot.com/bug?extid=6fba78f99b9afd4b5634
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=143237db500000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17eff0af500000

The issue was bisected to:

commit 93e72b3c612adcaca13d874fcc86c53e6c8da541
Author: Philippe Liard <pliard@...gle.com>
Date:   Tue Jun 2 04:45:23 2020 +0000

    squashfs: migrate from ll_rw_block usage to BIO

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1704fbfb500000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1484fbfb500000
console output: https://syzkaller.appspot.com/x/log.txt?x=1084fbfb500000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6fba78f99b9afd4b5634@...kaller.appspotmail.com
Fixes: 93e72b3c612a ("squashfs: migrate from ll_rw_block usage to BIO")

loop0: detected capacity change from 98 to 0
==================================================================
BUG: KASAN: vmalloc-out-of-bounds in memcpy include/linux/string.h:447 [inline]
BUG: KASAN: vmalloc-out-of-bounds in lzo_uncompress+0x44c/0x620 fs/squashfs/lzo_wrapper.c:80
Write of size 4096 at addr ffffc90000ea1e75 by task syz-executor001/8476

CPU: 0 PID: 8476 Comm: syz-executor001 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5/0x2c6 mm/kasan/report.c:230
 __kasan_report mm/kasan/report.c:396 [inline]
 kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/generic.c:179 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:185
 memcpy+0x39/0x60 mm/kasan/shadow.c:65
 memcpy include/linux/string.h:447 [inline]
 lzo_uncompress+0x44c/0x620 fs/squashfs/lzo_wrapper.c:80
 squashfs_decompress+0xcc/0x160 fs/squashfs/decompressor_single.c:70
 squashfs_read_data+0x1f8/0xe30 fs/squashfs/block.c:214
 squashfs_cache_get+0x4a9/0xd50 fs/squashfs/cache.c:110
 squashfs_read_metadata+0x134/0x460 fs/squashfs/cache.c:344
 squashfs_read_inode+0x182/0x1b40 fs/squashfs/inode.c:115
 squashfs_fill_super+0x1140/0x23b0 fs/squashfs/super.c:310
 get_tree_bdev+0x440/0x760 fs/super.c:1291
 vfs_get_tree+0x89/0x2f0 fs/super.c:1496
 do_new_mount fs/namespace.c:2878 [inline]
 path_mount+0x13ad/0x20c0 fs/namespace.c:3208
 do_mount fs/namespace.c:3221 [inline]
 __do_sys_mount fs/namespace.c:3429 [inline]
 __se_sys_mount fs/namespace.c:3406 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3406
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446d2a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 fd ad fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 da ad fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffc49d40db8 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffc49d40e10 RCX: 0000000000446d2a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffc49d40dd0
RBP: 00007ffc49d40dd0 R08: 00007ffc49d40e10 R09: 00007ffc00000015
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003


Memory state around the buggy address:
 ffffc90000ea1f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90000ea1f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90000ea2000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                   ^
 ffffc90000ea2080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffffc90000ea2100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================


---
This report is generated by a bot. It may contain errors.
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches