syzbot


KASAN: invalid-free in skb_free_head

Status: fixed on 2019/12/13 00:31
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+a0d209a4676664613e76@syzkaller.appspotmail.com
Fix commit: cf94da6f502d Bluetooth: Fix invalid-free in bcsp_close()
First crash: 1687d, last: 1687d
Cause bisection: introduced by (bisect log) :
commit 4ce9146e0370fcd573f0372d9b4e5a211112567c
Author: Tomas Bortoli <tomasbortoli@gmail.com>
Date: Tue May 28 13:42:58 2019 +0000

  Bluetooth: hci_bcsp: Fix memory leak in rx_skb

Crash: KASAN: invalid-free in skb_free_head (log)
Repro: C syz .config
  
Discussions (8)
Title Replies (including bot) Last reply
[PATCH 4.19 000/306] 4.19.87-stable review 359 (359) 2020/01/28 13:29
[PATCH 4.4 000/132] 4.4.204-stable review 142 (142) 2019/12/03 18:58
[PATCH 4.14 000/211] 4.14.157-stable review 220 (220) 2019/11/29 18:48
[PATCH 5.4 00/66] 5.4.1-stable review 75 (75) 2019/11/29 08:52
[PATCH 4.9 000/151] 4.9.204-stable review 156 (156) 2019/11/29 00:03
[PATCH 5.3 00/95] 5.3.14-stable review 100 (100) 2019/11/28 21:29
[PATCH] Fix invalid-free in bcsp_close() 5 (5) 2019/11/26 08:12
KASAN: invalid-free in skb_free_head 0 (1) 2019/11/01 15:42
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: invalid-free in skb_free_head (2) net C error 25 413d 478d 22/27 fixed on 2023/06/08 14:41

Sample crash report:
==================================================================
BUG: KASAN: double-free or invalid-free in skb_free_head+0x93/0xb0 net/core/skbuff.c:591

CPU: 1 PID: 9156 Comm: syz-executor213 Not tainted 5.4.0-rc5+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.constprop.0.cold+0xd4/0x30b mm/kasan/report.c:374
 kasan_report_invalid_free+0x65/0xa0 mm/kasan/report.c:468
 __kasan_slab_free+0x13a/0x150 mm/kasan/common.c:450
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 skb_free_head+0x93/0xb0 net/core/skbuff.c:591
 skb_release_data+0x42d/0x7c0 net/core/skbuff.c:611
 skb_release_all+0x4d/0x60 net/core/skbuff.c:665
 __kfree_skb net/core/skbuff.c:679 [inline]
 kfree_skb net/core/skbuff.c:697 [inline]
 kfree_skb+0x101/0x3c0 net/core/skbuff.c:691
 bcsp_close+0xc7/0x130 drivers/bluetooth/hci_bcsp.c:748
 hci_uart_tty_close+0x21e/0x280 drivers/bluetooth/hci_ldisc.c:548
 tty_ldisc_close.isra.0+0x119/0x1a0 drivers/tty/tty_ldisc.c:494
 tty_ldisc_kill+0x9c/0x160 drivers/tty/tty_ldisc.c:642
 tty_ldisc_release+0xe9/0x2b0 drivers/tty/tty_ldisc.c:814
 tty_release_struct+0x1b/0x50 drivers/tty/tty_io.c:1612
 tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1785
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x904/0x2e60 kernel/exit.c:817
 do_group_exit+0x135/0x360 kernel/exit.c:921
 get_signal+0x47c/0x2500 kernel/signal.c:2734
 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:159
 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:274 [inline]
 do_syscall_64+0x65f/0x760 arch/x86/entry/common.c:300
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446809
Code: Bad RIP value.
RSP: 002b:00007feedabcfdb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 00000000006dbc38 RCX: 0000000000446809
RDX: 000000000000005b RSI: 0000000020000080 RDI: 0000000000000007
RBP: 00000000006dbc30 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc3c
R13: 00007fff8abe57cf R14: 00007feedabd09c0 R15: 0000000000000000

Allocated by task 9184:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 __kasan_kmalloc mm/kasan/common.c:510 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:483
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:524
 __do_kmalloc_node mm/slab.c:3615 [inline]
 __kmalloc_node_track_caller+0x4e/0x70 mm/slab.c:3629
 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:141
 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:209
 alloc_skb include/linux/skbuff.h:1049 [inline]
 bt_skb_alloc include/net/bluetooth/bluetooth.h:339 [inline]
 bcsp_recv+0x8c1/0x13a0 drivers/bluetooth/hci_bcsp.c:670
 hci_uart_tty_receive+0x279/0x6e0 drivers/bluetooth/hci_ldisc.c:613
 tty_ldisc_receive_buf+0x15f/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x7d/0xb0 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x222/0x390 drivers/tty/tty_buffer.c:533
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 9184:
 save_stack+0x23/0x90 mm/kasan/common.c:69
 set_track mm/kasan/common.c:77 [inline]
 kasan_set_free_info mm/kasan/common.c:332 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:471
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:480
 __cache_free mm/slab.c:3425 [inline]
 kfree+0x10a/0x2c0 mm/slab.c:3756
 skb_free_head+0x93/0xb0 net/core/skbuff.c:591
 skb_release_data+0x42d/0x7c0 net/core/skbuff.c:611
 skb_release_all+0x4d/0x60 net/core/skbuff.c:665
 __kfree_skb net/core/skbuff.c:679 [inline]
 kfree_skb net/core/skbuff.c:697 [inline]
 kfree_skb+0x101/0x3c0 net/core/skbuff.c:691
 bcsp_recv+0x2d8/0x13a0 drivers/bluetooth/hci_bcsp.c:608
 hci_uart_tty_receive+0x279/0x6e0 drivers/bluetooth/hci_ldisc.c:613
 tty_ldisc_receive_buf+0x15f/0x1c0 drivers/tty/tty_buffer.c:465
 tty_port_default_receive_buf+0x7d/0xb0 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:481 [inline]
 flush_to_ldisc+0x222/0x390 drivers/tty/tty_buffer.c:533
 process_one_work+0x9af/0x1740 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8880946e4000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 0 bytes inside of
 8192-byte region [ffff8880946e4000, ffff8880946e6000)
The buggy address belongs to the page:
page:ffffea000251b900 refcount:1 mapcount:0 mapping:ffff8880aa4021c0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea00024a2e08 ffffea0002631c08 ffff8880aa4021c0
raw: 0000000000000000 ffff8880946e4000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880946e3f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880946e3f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880946e4000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff8880946e4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880946e4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/11/01 10:56 upstream e472c64aa4fa a41ca8fa .config console log report syz C ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.