KASAN: use-after-free Read in ath9k_htc_txcompletion_cb

From: syzbot
Date: Sat Apr 11 2020 - 07:09:19 EST


Hello,

syzbot found the following crash on:

HEAD commit: 0fa84af8 Merge tag 'usb-serial-5.7-rc1' of https://git.ker..
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=10af83b3e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=6b9c154b0c23aecf
dashboard link: https://syzkaller.appspot.com/bug?extid=809d3bdcdb4650cdbc83
compiler: gcc (GCC) 9.0.0 20181231 (experimental)

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

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+809d3bdcdb4650cdbc83@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in ath9k_htc_txcompletion_cb+0x285/0x2b0 drivers/net/wireless/ath/ath9k/htc_hst.c:341
Read of size 8 at addr ffff8881d1caf488 by task kworker/0:0/24267

CPU: 0 PID: 24267 Comm: kworker/0:0 Not tainted 5.6.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events request_firmware_work_func
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xef/0x16e lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xd3/0x314 mm/kasan/report.c:374
__kasan_report.cold+0x37/0x77 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:641
ath9k_htc_txcompletion_cb+0x285/0x2b0 drivers/net/wireless/ath/ath9k/htc_hst.c:341
hif_usb_regout_cb+0x10b/0x1b0 drivers/net/wireless/ath/ath9k/hif_usb.c:90
__usb_hcd_giveback_urb+0x1f2/0x470 drivers/usb/core/hcd.c:1648
usb_hcd_giveback_urb+0x368/0x420 drivers/usb/core/hcd.c:1713
dummy_timer+0x1258/0x32ae drivers/usb/gadget/udc/dummy_hcd.c:1966
call_timer_fn+0x195/0x6f0 kernel/time/timer.c:1404
expire_timers kernel/time/timer.c:1449 [inline]
__run_timers kernel/time/timer.c:1773 [inline]
__run_timers kernel/time/timer.c:1740 [inline]
run_timer_softirq+0x5f9/0x1500 kernel/time/timer.c:1786
__do_softirq+0x21e/0x950 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:373 [inline]
irq_exit+0x178/0x1a0 kernel/softirq.c:413
exiting_irq arch/x86/include/asm/apic.h:546 [inline]
smp_apic_timer_interrupt+0x141/0x540 arch/x86/kernel/apic/apic.c:1146
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
</IRQ>
RIP: 0010:arch_local_irq_restore arch/x86/include/asm/irqflags.h:85 [inline]
RIP: 0010:console_unlock+0xa6b/0xca0 kernel/printk/printk.c:2481
Code: 00 89 ee 48 c7 c7 60 3e 14 87 e8 10 c3 03 00 65 ff 0d c1 ed d8 7e e9 b5 f9 ff ff e8 0f 37 16 00 e8 0a 7f 1b 00 ff 74 24 30 9d <e9> fd fd ff ff e8 fb 36 16 00 48 8d 7d 08 48 89 f8 48 c1 e8 03 42
RSP: 0018:ffff8881d9227a50 EFLAGS: 00000293 ORIG_RAX: ffffffffffffff13
RAX: 0000000000000007 RBX: 0000000000000200 RCX: 0000000000000006
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff8881aba6d1cc
RBP: 0000000000000000 R08: ffff8881aba6c980 R09: fffffbfff1266485
R10: fffffbfff1266484 R11: ffffffff89332427 R12: ffffffff82a092b0
R13: ffffffff874d3950 R14: 0000000000000057 R15: dffffc0000000000
vprintk_emit+0x171/0x3d0 kernel/printk/printk.c:1996
vprintk_func+0x75/0x113 kernel/printk/printk_safe.c:386
printk+0xba/0xed kernel/printk/printk.c:2056
ath9k_htc_hw_init.cold+0x17/0x2a drivers/net/wireless/ath/ath9k/htc_hst.c:502
ath9k_hif_usb_firmware_cb+0x26b/0x500 drivers/net/wireless/ath/ath9k/hif_usb.c:1187
request_firmware_work_func+0x126/0x242 drivers/base/firmware_loader/main.c:976
process_one_work+0x94b/0x1620 kernel/workqueue.c:2266
worker_thread+0x96/0xe20 kernel/workqueue.c:2412
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 24267:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:515 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:488
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2786 [inline]
kmem_cache_alloc_node+0xdc/0x330 mm/slub.c:2822
__alloc_skb+0xba/0x5a0 net/core/skbuff.c:198
alloc_skb include/linux/skbuff.h:1081 [inline]
htc_connect_service+0x2cc/0x840 drivers/net/wireless/ath/ath9k/htc_hst.c:257
ath9k_wmi_connect+0xd2/0x1a0 drivers/net/wireless/ath/ath9k/wmi.c:265
ath9k_init_htc_services.constprop.0+0xb4/0x650 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146
ath9k_htc_probe_device+0x25a/0x1d80 drivers/net/wireless/ath/ath9k/htc_drv_init.c:959
ath9k_htc_hw_init+0x31/0x60 drivers/net/wireless/ath/ath9k/htc_hst.c:501
ath9k_hif_usb_firmware_cb+0x26b/0x500 drivers/net/wireless/ath/ath9k/hif_usb.c:1187
request_firmware_work_func+0x126/0x242 drivers/base/firmware_loader/main.c:976
process_one_work+0x94b/0x1620 kernel/workqueue.c:2266
worker_thread+0x96/0xe20 kernel/workqueue.c:2412
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 24267:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:337 [inline]
__kasan_slab_free+0x117/0x160 mm/kasan/common.c:476
slab_free_hook mm/slub.c:1444 [inline]
slab_free_freelist_hook mm/slub.c:1477 [inline]
slab_free mm/slub.c:3034 [inline]
kmem_cache_free+0x9b/0x360 mm/slub.c:3050
kfree_skbmem net/core/skbuff.c:622 [inline]
kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:616
__kfree_skb net/core/skbuff.c:679 [inline]
kfree_skb net/core/skbuff.c:696 [inline]
kfree_skb+0x102/0x3d0 net/core/skbuff.c:690
htc_connect_service.cold+0xa9/0x109 drivers/net/wireless/ath/ath9k/htc_hst.c:282
ath9k_wmi_connect+0xd2/0x1a0 drivers/net/wireless/ath/ath9k/wmi.c:265
ath9k_init_htc_services.constprop.0+0xb4/0x650 drivers/net/wireless/ath/ath9k/htc_drv_init.c:146
ath9k_htc_probe_device+0x25a/0x1d80 drivers/net/wireless/ath/ath9k/htc_drv_init.c:959
ath9k_htc_hw_init+0x31/0x60 drivers/net/wireless/ath/ath9k/htc_hst.c:501
ath9k_hif_usb_firmware_cb+0x26b/0x500 drivers/net/wireless/ath/ath9k/hif_usb.c:1187
request_firmware_work_func+0x126/0x242 drivers/base/firmware_loader/main.c:976
process_one_work+0x94b/0x1620 kernel/workqueue.c:2266
worker_thread+0x96/0xe20 kernel/workqueue.c:2412
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881d1caf3c0
which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 200 bytes inside of
224-byte region [ffff8881d1caf3c0, ffff8881d1caf4a0)
The buggy address belongs to the page:
page:ffffea0007472bc0 refcount:1 mapcount:0 mapping:ffff8881da16b400 index:0xffff8881d1caf280
flags: 0x200000000000200(slab)
raw: 0200000000000200 ffffea00074473c0 0000000900000009 ffff8881da16b400
raw: ffff8881d1caf280 00000000800c000b 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d1caf380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
ffff8881d1caf400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881d1caf480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff8881d1caf500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d1caf580: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.