syzbot


KASAN: use-after-free Read in skb_release_data (2)

Status: upstream: reported syz repro on 2020/03/03 17:50
Reported-by: syzbot+32ab713350c43e6736ca@syzkaller.appspotmail.com
First crash: 890d, last: 890d

Fix bisection: the fix commit could be any of (bisect log):
  5ac3462e1921 ALSA: pcm: oss: Avoid plugin buffer overflow
  59dfa43ef54a ALSA: pcm: oss: Remove WARNING from snd_pcm_plug_alloc() checks
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-49 KASAN: use-after-free Read in skb_release_data 1 1554d 1554d 0/3 auto-closed as invalid on 2019/02/22 12:31
linux-4.14 KASAN: use-after-free Read in skb_release_data 1 1102d 1102d 0/1 auto-closed as invalid on 2019/12/02 22:53
upstream KASAN: use-after-free Read in skb_release_data syz 7 1821d 1821d 3/23 fixed on 2017/10/24 06:54
upstream KASAN: use-after-free Read in skb_release_data (2) syz done done 1 892d 892d 0/23 upstream: reported syz repro on 2020/03/01 19:13

Sample crash report:
Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
Bluetooth: Invalid header checksum
==================================================================
BUG: KASAN: use-after-free in skb_release_data+0x563/0x7b0 net/core/skbuff.c:567
Read of size 1 at addr ffff8880994b77c2 by task kworker/u4:7/8147
Bluetooth: Invalid header checksum

CPU: 0 PID: 8147 Comm: kworker/u4:7 Not tainted 4.14.172-syzkaller #0
Bluetooth: Invalid header checksum
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Bluetooth: Invalid header checksum
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x13e/0x194 lib/dump_stack.c:58
 print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report mm/kasan/report.c:409 [inline]
 kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
 skb_release_data+0x563/0x7b0 net/core/skbuff.c:567
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 kfree_skb+0xae/0x340 net/core/skbuff.c:663
 h5_reset_rx+0x47/0x100 drivers/bluetooth/hci_h5.c:499
 h5_rx_3wire_hdr+0x2a2/0x360 drivers/bluetooth/hci_h5.c:409
Bluetooth: Invalid header checksum
 h5_recv+0x232/0x3b0 drivers/bluetooth/hci_h5.c:532
Bluetooth: Invalid header checksum
 hci_uart_tty_receive+0x1ec/0x4c0 drivers/bluetooth/hci_ldisc.c:616
 tty_ldisc_receive_buf+0x12e/0x170 drivers/tty/tty_buffer.c:459
 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:475 [inline]
 flush_to_ldisc+0x1dd/0x3f0 drivers/tty/tty_buffer.c:527
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

Allocated by task 8147:
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc mm/kasan/kasan.c:551 [inline]
 kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
 __do_kmalloc_node mm/slab.c:3682 [inline]
 __kmalloc_node_track_caller+0x4c/0x70 mm/slab.c:3696
 __kmalloc_reserve.isra.0+0x35/0xd0 net/core/skbuff.c:137
 __alloc_skb+0xca/0x4c0 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:980 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:336 [inline]
 h5_rx_pkt_start+0xbf/0x260 drivers/bluetooth/hci_h5.c:443
 h5_recv+0x232/0x3b0 drivers/bluetooth/hci_h5.c:532
 hci_uart_tty_receive+0x1ec/0x4c0 drivers/bluetooth/hci_ldisc.c:616
 tty_ldisc_receive_buf+0x12e/0x170 drivers/tty/tty_buffer.c:459
 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:37
 receive_buf drivers/tty/tty_buffer.c:475 [inline]
 flush_to_ldisc+0x1dd/0x3f0 drivers/tty/tty_buffer.c:527
 process_one_work+0x813/0x1540 kernel/workqueue.c:2114
 worker_thread+0x5d1/0x1070 kernel/workqueue.c:2248
 kthread+0x30d/0x420 kernel/kthread.c:232
Bluetooth: Invalid header checksum
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Bluetooth: Invalid header checksum

Freed by task 8494:
Bluetooth: Invalid header checksum
 save_stack+0x32/0xa0 mm/kasan/kasan.c:447
Bluetooth: Invalid header checksum
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xcb/0x260 mm/slab.c:3815
 skb_free_head+0x83/0xa0 net/core/skbuff.c:554
 skb_release_data+0x528/0x7b0 net/core/skbuff.c:574
 skb_release_all+0x46/0x60 net/core/skbuff.c:631
 __kfree_skb net/core/skbuff.c:645 [inline]
 kfree_skb+0xae/0x340 net/core/skbuff.c:663
 h5_reset_rx+0x47/0x100 drivers/bluetooth/hci_h5.c:499
 h5_rx_3wire_hdr+0x2a2/0x360 drivers/bluetooth/hci_h5.c:409
 h5_recv+0x232/0x3b0 drivers/bluetooth/hci_h5.c:532
 hci_uart_tty_receive+0x1ec/0x4c0 drivers/bluetooth/hci_ldisc.c:616
 tiocsti drivers/tty/tty_io.c:2186 [inline]
 tty_ioctl+0xd5b/0x1220 drivers/tty/tty_io.c:2572
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8880994b5900
 which belongs to the cache kmalloc-8192 of size 8192
The buggy address is located 7874 bytes inside of
 8192-byte region [ffff8880994b5900, ffff8880994b7900)
The buggy address belongs to the page:
page:ffffea0002652d00 count:1 mapcount:0 mapping:ffff8880994b5900 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880994b5900 0000000000000000 0000000100000001
raw: ffffea0001e04320 ffffea0002613520 ffff88812fe55080 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880994b7680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880994b7700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880994b7780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8880994b7800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880994b7880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/03/03 17:49 linux-4.14.y 78d697fc93f9 350a7a26 .config log report syz