KASAN: use-after-free Read in chaoskey_disconnect

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syzbot

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Oct 30, 2019, 8:52:09 AM10/30/19
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Hello,

syzbot found the following crash on:

HEAD commit: ff6409a6 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=15e1ba24e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=169b8904e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166f3104e00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+6d8505...@syzkaller.appspotmail.com

usb 3-1: string descriptor 0 read error: -71
usb 3-1: USB disconnect, device number 2
==================================================================
BUG: KASAN: use-after-free in atomic_read
include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x72/0x1e0
lib/refcount.c:123
Read of size 4 at addr ffff8881cf679820 by task kworker/1:1/1730

CPU: 1 PID: 1730 Comm: kworker/1:1 Not tainted 5.4.0-rc5+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:634
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x128/0x190 mm/kasan/generic.c:192
atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
refcount_inc_not_zero_checked+0x72/0x1e0 lib/refcount.c:123
refcount_inc_checked+0x12/0x60 lib/refcount.c:156
get_task_struct include/linux/sched/task.h:110 [inline]
kthread_stop+0x6c/0x610 kernel/kthread.c:554
hwrng_unregister+0x190/0x210 drivers/char/hw_random/core.c:538
chaoskey_disconnect+0x1b2/0x200 drivers/usb/misc/chaoskey.c:232
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x420/0xb20 drivers/base/core.c:2376
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2200
hub_port_connect drivers/usb/core/hub.c:5035 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
port_event drivers/usb/core/hub.c:5470 [inline]
hub_event+0x16f2/0x3800 drivers/usb/core/hub.c:5552
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 2:
save_stack+0x1b/0x80 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+0xbf/0xd0 mm/kasan/common.c:483
slab_post_alloc_hook mm/slab.h:584 [inline]
slab_alloc_node mm/slub.c:2779 [inline]
kmem_cache_alloc_node+0xdc/0x310 mm/slub.c:2815
alloc_task_struct_node kernel/fork.c:169 [inline]
dup_task_struct kernel/fork.c:865 [inline]
copy_process+0x4201/0x6470 kernel/fork.c:1851
_do_fork+0x129/0xec0 kernel/fork.c:2366
kernel_thread+0xaa/0xe0 kernel/fork.c:2453
create_kthread kernel/kthread.c:278 [inline]
kthreadd+0x4a2/0x680 kernel/kthread.c:596
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Freed by task 16:
save_stack+0x1b/0x80 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+0x130/0x180 mm/kasan/common.c:471
slab_free_hook mm/slub.c:1424 [inline]
slab_free_freelist_hook mm/slub.c:1475 [inline]
slab_free mm/slub.c:3025 [inline]
kmem_cache_free+0xb9/0x380 mm/slub.c:3041
__put_task_struct+0x1e2/0x4c0 kernel/fork.c:748
put_task_struct include/linux/sched/task.h:119 [inline]
delayed_put_task_struct+0x1b4/0x2c0 kernel/exit.c:182
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x630/0x1ca0 kernel/rcu/tree.c:2377
__do_softirq+0x221/0x912 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881cf679800
which belongs to the cache task_struct of size 5888
The buggy address is located 32 bytes inside of
5888-byte region [ffff8881cf679800, ffff8881cf67af00)
The buggy address belongs to the page:
page:ffffea00073d9e00 refcount:1 mapcount:0 mapping:ffff8881da116000
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da116000
raw: 0000000000000000 0000000080050005 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cf679700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881cf679780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881cf679800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881cf679880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881cf679900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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 syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

Stephen Boyd

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Nov 15, 2019, 1:19:23 PM11/15/19
to alexandr...@bootlin.com, andre...@google.com, ar...@arndb.de, gre...@linuxfoundation.org, her...@gondor.apana.org.au, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, lvi...@redhat.com, mchehab...@kernel.org, m...@selenic.com, syzbot, syzkall...@googlegroups.com, ty...@mit.edu
Quoting syzbot (2019-10-30 05:52:08)
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: ff6409a6 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=15e1ba24e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
> dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=169b8904e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166f3104e00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6d8505...@syzkaller.appspotmail.com
>

Ok, let's try that again

#syz test: https://github.com/google/kasan.git ff6409a6

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 5b799aa973a3..c487709499fc 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2440,8 +2440,8 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
* We'll be woken up again once below random_write_wakeup_thresh,
* or when the calling thread is about to terminate.
*/
- wait_event_freezable(random_write_wait,
- kthread_should_stop() ||
+ wait_event_interruptible(random_write_wait,
+ kthread_should_stop() || freezing(current) ||
ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
mix_pool_bytes(poolp, buffer, count);
credit_entropy_bits(poolp, entropy);

syzbot

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Nov 16, 2019, 12:55:01 AM11/16/19
to alexandr...@bootlin.com, andre...@google.com, ar...@arndb.de, gre...@linuxfoundation.org, her...@gondor.apana.org.au, linux-...@vger.kernel.org, linux-...@vger.kernel.org, linu...@vger.kernel.org, lvi...@redhat.com, mch...@kernel.org, m...@selenic.com, swb...@chromium.org, syzkall...@googlegroups.com, ty...@mit.edu
Hello,

syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: use-after-free Read in chaoskey_disconnect

usb 5-1: USB disconnect, device number 2
==================================================================
BUG: KASAN: use-after-free in atomic_read
include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x72/0x1e0
lib/refcount.c:123
Read of size 4 at addr ffff8881d3106020 by task kworker/0:1/12

CPU: 0 PID: 12 Comm: kworker/0:1 Not tainted 5.4.0-rc5+ #0
Freed by task 9:
save_stack+0x1b/0x80 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+0x130/0x180 mm/kasan/common.c:471
slab_free_hook mm/slub.c:1424 [inline]
slab_free_freelist_hook mm/slub.c:1475 [inline]
slab_free mm/slub.c:3025 [inline]
kmem_cache_free+0xb9/0x380 mm/slub.c:3041
__put_task_struct+0x1e2/0x4c0 kernel/fork.c:748
put_task_struct include/linux/sched/task.h:119 [inline]
delayed_put_task_struct+0x1b4/0x2c0 kernel/exit.c:182
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x630/0x1ca0 kernel/rcu/tree.c:2377
__do_softirq+0x221/0x912 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881d3106000
which belongs to the cache task_struct of size 5888
The buggy address is located 32 bytes inside of
5888-byte region [ffff8881d3106000, ffff8881d3107700)
The buggy address belongs to the page:
page:ffffea00074c4000 refcount:1 mapcount:0 mapping:ffff8881da116000
index:0xffff8881d3101800 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da116000
raw: ffff8881d3101800 0000000080050004 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881d3105f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881d3105f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ffff8881d3106000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d3106080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d3106100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: ff6409a6 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=16dd8772e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=14236abae00000

syzbot

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Nov 19, 2019, 3:59:01 AM11/19/19
to linu...@vger.kernel.org, one...@suse.com, syzkall...@googlegroups.com
Hello,

syzbot has tested the proposed patch and the reproducer did not trigger
crash:

Reported-and-tested-by:
syzbot+6d8505...@syzkaller.appspotmail.com

Tested on:

commit: ff6409a6 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=1660128ce00000

Note: testing is done by a robot and is best-effort only.

Oliver Neukum

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May 6, 2020, 5:56:15 AM5/6/20
to syzbot, alexandr...@bootlin.com, andre...@google.com, ar...@arndb.de, gre...@linuxfoundation.org, her...@gondor.apana.org.au, lvi...@redhat.com, mchehab...@kernel.org, m...@selenic.com, swb...@chromium.org, syzkall...@googlegroups.com, ty...@mit.edu
Am Mittwoch, den 30.10.2019, 05:52 -0700 schrieb syzbot:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: ff6409a6 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=15e1ba24e00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
> dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=169b8904e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166f3104e00000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6d8505...@syzkaller.appspotmail.com
>
> usb 3-1: string descriptor 0 read error: -71
> usb 3-1: USB disconnect, device number 2
> ==================================================================
> BUG: KASAN: use-after-free in atomic_read
> include/asm-generic/atomic-instrumented.h:26 [inline]
> BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x72/0x1e0
> lib/refcount.c:123
> Read of size 4 at addr ffff8881cf679820 by task kworker/1:1/1730

0001-chaoskey-make-sure-an-unregistration-of-the-hwrng-is.patch

syzbot

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May 6, 2020, 6:24:06 AM5/6/20
to alexandr...@bootlin.com, andre...@google.com, ar...@arndb.de, gre...@linuxfoundation.org, her...@gondor.apana.org.au, lvi...@redhat.com, mch...@kernel.org, m...@selenic.com, one...@suse.de, swb...@chromium.org, syzkall...@googlegroups.com, ty...@mit.edu
Hello,

syzbot has tested the proposed patch but the reproducer still triggered crash:
KASAN: use-after-free Read in chaoskey_disconnect

usb 6-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0
usb 6-1: string descriptor 0 read error: -71
usb 6-1: USB disconnect, device number 4
==================================================================
BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
BUG: KASAN: use-after-free in refcount_inc_not_zero_checked+0x72/0x1e0 lib/refcount.c:123
Read of size 4 at addr ffff8881ce51c820 by task kworker/0:2/101

CPU: 0 PID: 101 Comm: kworker/0:2 Not tainted 5.4.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description.constprop.0+0x36/0x50 mm/kasan/report.c:374
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:634
check_memory_region_inline mm/kasan/generic.c:185 [inline]
check_memory_region+0x128/0x190 mm/kasan/generic.c:192
atomic_read include/asm-generic/atomic-instrumented.h:26 [inline]
refcount_inc_not_zero_checked+0x72/0x1e0 lib/refcount.c:123
refcount_inc_checked+0x12/0x60 lib/refcount.c:156
get_task_struct include/linux/sched/task.h:110 [inline]
kthread_stop+0x6c/0x610 kernel/kthread.c:554
hwrng_unregister+0x190/0x210 drivers/char/hw_random/core.c:538
chaoskey_disconnect+0x1bc/0x240 drivers/usb/misc/chaoskey.c:232
Freed by task 149:
save_stack+0x1b/0x80 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+0x130/0x180 mm/kasan/common.c:471
slab_free_hook mm/slub.c:1424 [inline]
slab_free_freelist_hook mm/slub.c:1475 [inline]
slab_free mm/slub.c:3025 [inline]
kmem_cache_free+0xb9/0x380 mm/slub.c:3041
__put_task_struct+0x1e2/0x4c0 kernel/fork.c:748
put_task_struct include/linux/sched/task.h:119 [inline]
delayed_put_task_struct+0x1b4/0x2c0 kernel/exit.c:182
__rcu_reclaim kernel/rcu/rcu.h:222 [inline]
rcu_do_batch kernel/rcu/tree.c:2157 [inline]
rcu_core+0x630/0x1ca0 kernel/rcu/tree.c:2377
__do_softirq+0x221/0x912 kernel/softirq.c:292

The buggy address belongs to the object at ffff8881ce51c800
which belongs to the cache task_struct of size 5888
The buggy address is located 32 bytes inside of
5888-byte region [ffff8881ce51c800, ffff8881ce51df00)
The buggy address belongs to the page:
page:ffffea0007394600 refcount:1 mapcount:0 mapping:ffff8881da116000 index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 dead000000000100 dead000000000122 ffff8881da116000
raw: 0000000000000000 0000000000050005 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881ce51c700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881ce51c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881ce51c800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881ce51c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881ce51c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: ff6409a6 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13cc0950100000
kernel config: https://syzkaller.appspot.com/x/.config?x=3230c37d442895b7
dashboard link: https://syzkaller.appspot.com/bug?extid=6d8505fcdf25f00ac276
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=10d479d4100000

Andrey Konovalov

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Jun 18, 2020, 8:12:36 AM6/18/20
to syzbot, alexandr...@bootlin.com, Arnd Bergmann, Greg Kroah-Hartman, Herbert Xu, linux-...@vger.kernel.org, LKML, USB list, lvi...@redhat.com, mchehab...@kernel.org, m...@selenic.com, swb...@chromium.org, syzkaller-bugs, Theodore Ts'o
#syz fix: USB: chaoskey: fix use-after-free on release
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