Re: KASAN: use-after-free Read in hci_send_acl

2020-08-03 Thread syzbot
syzbot has bisected this issue to:

commit 4ffcd582301bd020b1f9d00c55473af305ec19b5
Author: Michael Chan 
Date:   Mon Sep 19 07:58:07 2016 +

bnxt_en: Pad TX packets below 52 bytes.

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=167b0f0490
start commit:   ac3a0c84 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:   upstream
final oops: https://syzkaller.appspot.com/x/report.txt?x=157b0f0490
console output: https://syzkaller.appspot.com/x/log.txt?x=117b0f0490
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0cfcf935bcc94d2
dashboard link: https://syzkaller.appspot.com/bug?extid=98228e7407314d2d4ba2
syz repro:  https://syzkaller.appspot.com/x/repro.syz?x=152f190490
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1482dfca90

Reported-by: syzbot+98228e7407314d2d4...@syzkaller.appspotmail.com
Fixes: 4ffcd582301b ("bnxt_en: Pad TX packets below 52 bytes.")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection


KASAN: use-after-free Read in hci_send_acl

2020-08-02 Thread syzbot
Hello,

syzbot found the following issue on:

HEAD commit:ac3a0c84 Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:   upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1348290490
kernel config:  https://syzkaller.appspot.com/x/.config?x=c0cfcf935bcc94d2
dashboard link: https://syzkaller.appspot.com/bug?extid=98228e7407314d2d4ba2
compiler:   gcc (GCC) 10.1.0-syz 20200507
syz repro:  https://syzkaller.appspot.com/x/repro.syz?x=152f190490
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1482dfca90

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+98228e7407314d2d4...@syzkaller.appspotmail.com

==
BUG: KASAN: use-after-free in hci_send_acl+0xabe/0xc60 
net/bluetooth/hci_core.c:3991
Read of size 8 at addr 8880a6ff8818 by task kworker/u5:2/6855

CPU: 1 PID: 6855 Comm: kworker/u5:2 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_send_acl+0xabe/0xc60 net/bluetooth/hci_core.c:3991
 l2cap_send_cmd+0x6d5/0x8a0 net/bluetooth/l2cap_core.c:949
 l2cap_send_move_chan_cfm_icid net/bluetooth/l2cap_core.c:4917 [inline]
 l2cap_move_fail net/bluetooth/l2cap_core.c:5401 [inline]
 l2cap_move_channel_rsp net/bluetooth/l2cap_core.c:5440 [inline]
 l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5719 [inline]
 l2cap_sig_channel net/bluetooth/l2cap_core.c:6418 [inline]
 l2cap_recv_frame+0x6936/0xae10 net/bluetooth/l2cap_core.c:7660
 l2cap_recv_acldata+0x7f6/0x8e0 net/bluetooth/l2cap_core.c:8313
 hci_acldata_packet net/bluetooth/hci_core.c:4520 [inline]
 hci_rx_work+0x4c7/0xb10 net/bluetooth/hci_core.c:4710
 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 6855:
 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
 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 hci_chan_create+0x9b/0x330 net/bluetooth/hci_conn.c:1692
 l2cap_conn_add.part.0+0x1e/0xe10 net/bluetooth/l2cap_core.c:7699
 l2cap_conn_add net/bluetooth/l2cap_core.c:8139 [inline]
 l2cap_connect_cfm+0x23b/0x1090 net/bluetooth/l2cap_core.c:8097
 hci_connect_cfm include/net/bluetooth/hci_core.h:1340 [inline]
 hci_remote_features_evt net/bluetooth/hci_event.c:3210 [inline]
 hci_event_packet+0x3e01/0x86f5 net/bluetooth/hci_event.c:6061
 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

Freed by task 6855:
 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
 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:4999 [inline]
 hci_event_packet+0x319a/0x86f5 net/bluetooth/hci_event.c:6188
 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

The buggy address belongs to the object at 8880a6ff8800
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [8880a6ff8800, 8880a6ff8880)
The buggy address belongs to the page:
page:ea00029bfe00 refcount:1 mapcount:0 mapping: 
index:0x8880a6ff8c00
flags: 0xfffe000200(slab)
raw: 00fffe000200 ea0002934388 8880aa001540 8880aa000700
raw: 8880a6ff8c00 8880a6ff8000 0001000c 
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 8880a6ff8700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 8880a6ff8780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>8880a6ff8800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
 8880a6ff8880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 8880a6ff8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb