KASAN: slab-out-of-bounds Read in hci_le_meta_evt

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 5a30a789 Merge tag 'x86-urgent-2020-08-02' of git://git.ke..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11cd21cc900000
kernel config: https://syzkaller.appspot.com/x/.config?x=c0cfcf935bcc94d2
dashboard link: https://syzkaller.appspot.com/bug?extid=24ebd650e20bd263ca01
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10fd4504900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=14aa36a4900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+24ebd6...@syzkaller.appspotmail.com

Bluetooth: hci0: unknown advertising packet type: 0x2b
==================================================================
BUG: KASAN: slab-out-of-bounds in hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5850 [inline]
BUG: KASAN: slab-out-of-bounds in hci_le_meta_evt+0x380c/0x3eb0 net/bluetooth/hci_event.c:5914
Read of size 1 at addr ffff8880a727de0c by task kworker/u5:0/1535

CPU: 1 PID: 1535 Comm: kworker/u5:0 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
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/0x436 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
hci_le_direct_adv_report_evt net/bluetooth/hci_event.c:5850 [inline]
hci_le_meta_evt+0x380c/0x3eb0 net/bluetooth/hci_event.c:5914
hci_event_packet+0x245a/0x86f5 net/bluetooth/hci_event.c:6167
hci_rx_work+0x22e/0xb10 net/bluetooth/hci_core.c:4705
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:291
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 6834:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
__kmalloc_reserve net/core/skbuff.c:142 [inline]
__alloc_skb+0xae/0x550 net/core/skbuff.c:210
alloc_skb include/linux/skbuff.h:1083 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:377 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:165 [inline]
vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:285
call_write_iter include/linux/fs.h:1908 [inline]
new_sync_write+0x422/0x650 fs/read_write.c:503
vfs_write+0x59d/0x6b0 fs/read_write.c:578
ksys_write+0x12d/0x250 fs/read_write.c:631
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6627:
save_stack+0x1b/0x40 mm/kasan/common.c:48
set_track mm/kasan/common.c:56 [inline]
kasan_set_free_info mm/kasan/common.c:316 [inline]
__kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
__cache_free mm/slab.c:3426 [inline]
kfree+0x103/0x2c0 mm/slab.c:3757
tomoyo_find_next_domain+0x81d/0x1f77 security/tomoyo/domain.c:885
tomoyo_bprm_check_security security/tomoyo/tomoyo.c:101 [inline]
tomoyo_bprm_check_security+0x121/0x1a0 security/tomoyo/tomoyo.c:91
security_bprm_check+0x45/0xa0 security/security.c:840
search_binary_handler fs/exec.c:1737 [inline]
exec_binprm fs/exec.c:1790 [inline]
__do_execve_file+0x1577/0x2ee0 fs/exec.c:1926
do_execveat_common fs/exec.c:1980 [inline]
do_execve+0x35/0x50 fs/exec.c:1997
__do_sys_execve fs/exec.c:2073 [inline]
__se_sys_execve fs/exec.c:2068 [inline]
__x64_sys_execve+0x7c/0xa0 fs/exec.c:2068
do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a727dc00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 12 bytes to the right of
512-byte region [ffff8880a727dc00, ffff8880a727de00)
The buggy address belongs to the page:
page:ffffea00029c9f40 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029e3848 ffffea0002731b88 ffff8880aa000a80
raw: 0000000000000000 ffff8880a727d000 0000000100000004 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a727dd00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff8880a727dd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a727de00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8880a727de80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880a727df00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
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[Russell King - ARM Linux admin]

Dear syzbot,

Please explain why you are spamming me with all these reports - four so
far. I don't understand why you think I should be doing anything with
these.

Thanks.

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

[Eric Biggers]

On Mon, Aug 03, 2020 at 06:12:33PM +0100, Russell King - ARM Linux admin wrote:
> Dear syzbot,
>
> Please explain why you are spamming me with all these reports - four so
> far. I don't understand why you think I should be doing anything with
> these.
>
> Thanks.

syzbot just uses get_maintainer.pl.

$ ./scripts/get_maintainer.pl net/bluetooth/hci_event.c
Marcel Holtmann <mar...@holtmann.org> (maintainer:BLUETOOTH SUBSYSTEM)
Johan Hedberg <johan....@gmail.com> (maintainer:BLUETOOTH SUBSYSTEM)
"David S. Miller" <da...@davemloft.net> (maintainer:NETWORKING [GENERAL])
Jakub Kicinski <ku...@kernel.org> (maintainer:NETWORKING [GENERAL])
Russell King <li...@armlinux.org.uk> (maintainer:SFF/SFP/SFP+ MODULE SUPPORT)
linux-b...@vger.kernel.org (open list:BLUETOOTH SUBSYSTEM)
net...@vger.kernel.org (open list:NETWORKING [GENERAL])
linux-...@vger.kernel.org (open list)

[Russell King - ARM Linux admin]

Ah, and, because the file mentions "phylink" (although it makes no use
of the phylink code), get_maintainer spits out my address. Great.

So how do I get get_maintainer to identify patches that are making use
of phylink, but avoid this bluetooth code... (that's not a question.)

[Eric Biggers]

I think "K: " (content regex) in MAINTAINERS is best avoided. This isn't the
first time that someone has volunteered to maintain all files containing $foo,
then complained when they receive emails for those files as they requested...

If you do really want to use it, can you use a more specific regex? E.g. a
regex that matches "#include <linux/phylink.h>" or some specific function(s)?

- Eric