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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3f8a27f9e27b Linux 4.19.211
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=14e691e4880000
kernel config: https://syzkaller.appspot.com/x/.config?x=9b9277b418617afe
dashboard link: https://syzkaller.appspot.com/bug?extid=2730d8d265202f5a580b
compiler: gcc version 10.2.1 20210110 (Debian 10.2.1-6)

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2730d8...@syzkaller.appspotmail.com

Bluetooth: hci0: advertising data len corrected
Bluetooth: hci0: advertising data len corrected
Bluetooth: Unknown advertising packet type: 0x63c0
Bluetooth: Unknown advertising packet type: 0x4b16
==================================================================
BUG: KASAN: slab-out-of-bounds in process_adv_report+0xd8f/0xe70 net/bluetooth/hci_event.c:5215
Read of size 1 at addr ffff88804c88ff76 by task kworker/u5:5/8143

CPU: 0 PID: 8143 Comm: kworker/u5:5 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
Workqueue: hci0 hci_rx_work
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load1_noabort+0x88/0x90 mm/kasan/report.c:430
process_adv_report+0xd8f/0xe70 net/bluetooth/hci_event.c:5215
hci_le_ext_adv_report_evt net/bluetooth/hci_event.c:5470 [inline]
hci_le_meta_evt+0x2049/0x3f20 net/bluetooth/hci_event.c:5714
hci_event_packet+0x34ad/0x7e20 net/bluetooth/hci_event.c:5959
hci_rx_work+0x4ad/0xc70 net/bluetooth/hci_core.c:4380
process_one_work+0x864/0x1570 kernel/workqueue.c:2153
worker_thread+0x64c/0x1130 kernel/workqueue.c:2296
kthread+0x33f/0x460 kernel/kthread.c:259
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Allocated by task 8411:
__do_kmalloc_node mm/slab.c:3689 [inline]
__kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3703
__kmalloc_reserve net/core/skbuff.c:137 [inline]
__alloc_skb+0xae/0x560 net/core/skbuff.c:205
alloc_skb include/linux/skbuff.h:995 [inline]
bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline]
vhci_get_user drivers/bluetooth/hci_vhci.c:180 [inline]
vhci_write+0xbd/0x450 drivers/bluetooth/hci_vhci.c:299
call_write_iter include/linux/fs.h:1821 [inline]
new_sync_write fs/read_write.c:474 [inline]
__vfs_write+0x51b/0x770 fs/read_write.c:487
vfs_write+0x1f3/0x540 fs/read_write.c:549
ksys_write+0x12b/0x2a0 fs/read_write.c:599
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7529:
__cache_free mm/slab.c:3503 [inline]
kfree+0xcc/0x210 mm/slab.c:3822
skb_free_head net/core/skbuff.c:563 [inline]
skb_release_data+0x6de/0x920 net/core/skbuff.c:583
skb_release_all net/core/skbuff.c:640 [inline]
__kfree_skb net/core/skbuff.c:654 [inline]
consume_skb+0x113/0x3d0 net/core/skbuff.c:714
skb_free_datagram+0x16/0xf0 net/core/datagram.c:329
netlink_recvmsg+0x627/0xea0 net/netlink/af_netlink.c:1996
sock_recvmsg_nosec net/socket.c:859 [inline]
sock_recvmsg net/socket.c:866 [inline]
sock_recvmsg+0xca/0x110 net/socket.c:862
___sys_recvmsg+0x255/0x570 net/socket.c:2389
__sys_recvmsg net/socket.c:2438 [inline]
__do_sys_recvmsg net/socket.c:2448 [inline]
__se_sys_recvmsg net/socket.c:2445 [inline]
__x64_sys_recvmsg+0x12f/0x220 net/socket.c:2445
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88804c88fb40
which belongs to the cache kmalloc-1024 of size 1024
The buggy address is located 54 bytes to the right of
1024-byte region [ffff88804c88fb40, ffff88804c88ff40)
The buggy address belongs to the page:
page:ffffea0001322380 count:1 mapcount:0 mapping:ffff88813bff0ac0 index:0xffff88804c88f6c0 compound_mapcount: 0
flags: 0xfff00000008100(slab|head)
raw: 00fff00000008100 ffffea0001318888 ffffea0002ba1308 ffff88813bff0ac0
raw: ffff88804c88f6c0 ffff88804c88e040 0000000100000005 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88804c88fe00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88804c88fe80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804c88ff00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
^
ffff88804c88ff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88804c890000: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================


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