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

From: syzbot
Date: Sun Jul 14 2019 - 20:24:12 EST

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syzbot has found a reproducer for the following crash on:

HEAD commit: 6a3599ce usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=169777b8600000
kernel config: https://syzkaller.appspot.com/x/.config?x=d90745bdf884fc0a
dashboard link: https://syzkaller.appspot.com/bug?extid=5b7575b3f6820232e17c
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11dd33b8600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5b7575b3f6820232e17c@xxxxxxxxxxxxxxxxxxxxxxxxx

==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x3a5d/0x5340 kernel/locking/lockdep.c:3665
Read of size 8 at addr ffff8881cfd80808 by task v4l_id/3788

CPU: 1 PID: 3788 Comm: v4l_id Not tainted 5.2.0-rc6+ #14
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+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x67/0x231 mm/kasan/report.c:188
__kasan_report.cold+0x1a/0x32 mm/kasan/report.c:317
kasan_report+0xe/0x20 mm/kasan/common.c:614
__lock_acquire+0x3a5d/0x5340 kernel/locking/lockdep.c:3665
lock_acquire+0x100/0x2b0 kernel/locking/lockdep.c:4303
__mutex_lock_common kernel/locking/mutex.c:926 [inline]
__mutex_lock+0xf9/0x12b0 kernel/locking/mutex.c:1073
__video_do_ioctl+0x5c7/0xb30 drivers/media/v4l2-core/v4l2-ioctl.c:2839
video_usercopy+0x446/0xee0 drivers/media/v4l2-core/v4l2-ioctl.c:3053
v4l2_ioctl+0x147/0x1a0 drivers/media/v4l2-core/v4l2-dev.c:360
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:696
ksys_ioctl+0x9b/0xc0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:718
do_syscall_64+0xb7/0x560 arch/x86/entry/common.c:301
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fbaeda44347
Code: 90 90 90 48 8b 05 f1 fa 2a 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 90 90 90 90 90 90 90 90 90 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c1 fa 2a 00 31 d2 48 29 c2 64
RSP: 002b:00007ffeeb4faf58 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fbaeda44347
RDX: 00007ffeeb4faf60 RSI: 0000000080685600 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400884
R13: 00007ffeeb4fb0b0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 107:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:489 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:462
slab_post_alloc_hook mm/slab.h:437 [inline]
slab_alloc_node mm/slub.c:2748 [inline]
__kmalloc_node_track_caller+0xee/0x370 mm/slub.c:4363
alloc_dr drivers/base/devres.c:103 [inline]
devm_kmalloc+0x87/0x190 drivers/base/devres.c:815
devm_kzalloc include/linux/device.h:679 [inline]
usb_raremono_probe+0x2f/0x231 drivers/media/radio/radio-raremono.c:298
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_set_configuration+0xdf6/0x1670 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x8c1/0x1016 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1b3d/0x35f0 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 107:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:451
slab_free_hook mm/slub.c:1421 [inline]
slab_free_freelist_hook mm/slub.c:1448 [inline]
slab_free mm/slub.c:2994 [inline]
kfree+0xd7/0x280 mm/slub.c:3949
release_nodes+0x4a1/0x910 drivers/base/devres.c:508
devres_release_all+0x74/0xc3 drivers/base/devres.c:529
__device_release_driver drivers/base/dd.c:1085 [inline]
device_release_driver_internal+0x21b/0x4c0 drivers/base/dd.c:1112
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x460/0xb80 drivers/base/core.c:2274
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x830 drivers/usb/core/hub.c:2199
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x143d/0x35f0 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8881cfd80000
which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2056 bytes inside of
4096-byte region [ffff8881cfd80000, ffff8881cfd81000)
The buggy address belongs to the page:
page:ffffea00073f6000 refcount:1 mapcount:0 mapping:ffff8881dac02600 index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000200 ffff8881dac02600
raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cfd80700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cfd80780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

ffff8881cfd80800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^
ffff8881cfd80880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cfd80900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

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Previous message: Turritopsis Dohrnii Teo En Ming: "What are the differences between cointelpro and coamdpro?"
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