Hi Andrey,
I have added NULL check for usb_ifnum_to_if() and send a patch.
Please re-test it.
~arvind
On Monday 09 October 2017 11:20 PM, Andrey Konovalov wrote:
Hi!
I've got the following report while fuzzing the kernel with syzkaller.
On commit 8a5776a5f49812d29fe4b2d0a2d71675c3facf3f (4.14-rc4).
It seems that the return value of usb_ifnum_to_if() can be NULL and
needs to be checked.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 1497 Comm: kworker/1:1 Not tainted
4.14.0-rc4-43418-g43a3f84d2109-dirty #380
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
Workqueue: usb_hub_wq hub_event
task: 88006a5618c0 task.stack: 880068bc8000
RIP: 0010:imon_probe+0x231/0x3f10 drivers/media/rc/imon.c:2519
RSP: 0018:880068bce2d8 EFLAGS: 00010206
RAX: RBX: 8800627dd500 RCX: 0027
RDX: dc00 RSI: RDI: 0138
RBP: 880068bce5e8 R08: 88006a5618c0 R09: 84b380fc
R10: 880068bce2c8 R11: 11000d4ac5b3 R12: 88006183
R13: 880061830008 R14: 883fa200 R15: 883fa080
FS: () GS:88006c50() knlGS:
CS: 0010 DS: ES: CR0: 80050033
CR2: 206cbffc CR3: 61085000 CR4: 06e0
Call Trace:
usb_probe_interface+0x35d/0x8e0 drivers/usb/core/driver.c:361
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_set_configuration+0x104e/0x1870 drivers/usb/core/message.c:1932
generic_probe+0x73/0xe0 drivers/usb/core/generic.c:174
usb_probe_device+0xaf/0xe0 drivers/usb/core/driver.c:266
really_probe drivers/base/dd.c:413
driver_probe_device+0x610/0xa00 drivers/base/dd.c:557
__device_attach_driver+0x230/0x290 drivers/base/dd.c:653
bus_for_each_drv+0x161/0x210 drivers/base/bus.c:463
__device_attach+0x26e/0x3d0 drivers/base/dd.c:710
device_initial_probe+0x1f/0x30 drivers/base/dd.c:757
bus_probe_device+0x1eb/0x290 drivers/base/bus.c:523
device_add+0xd0b/0x1660 drivers/base/core.c:1835
usb_new_device+0x7b8/0x1020 drivers/usb/core/hub.c:2457
hub_port_connect drivers/usb/core/hub.c:4903
hub_port_connect_change drivers/usb/core/hub.c:5009
port_event drivers/usb/core/hub.c:5115
hub_event+0x194d/0x3740 drivers/usb/core/hub.c:5195
process_one_work+0xc7f/0x1db0 kernel/workqueue.c:2119
worker_thread+0x221/0x1850 kernel/workqueue.c:2253
kthread+0x3a1/0x470 kernel/kthread.c:231
ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431
Code: ff e8 a4 81 cb 01 31 f6 48 89 df e8 2a cc 65 ff 0f ae f0 48 8d
b8 38 01 00 00 48 ba 00 00 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 <80>
3c 11 00 0f 85 e8 31 00 00 48 8b 98 38 01 00 00 0f ae f0 44
RIP: imon_probe+0x231/0x3f10 RSP: 880068bce2d8
---[ end trace 07febd2eebe02f84 ]---
