Re: [PATCH v2] HID: usbhid: fix out-of-bounds bug

From: Alan Stern
Date: Tue Oct 10 2017 - 10:22:30 EST


On Tue, 10 Oct 2017, Jaejoong Kim wrote:

> Hi,
>
> To. Jiri, Alan,
>
> Could you please review this patch?
>
> To. Andey,
>
> Could you please test with this patch for KASAN OOB error?
>
> Thanks, jaejoong
>
> 2017-09-28 19:16 GMT+09:00 Jaejoong Kim <climbbb.kim@xxxxxxxxx>:
> > The hid descriptor identifies the length and type of subordinate
> > descriptors for a device. If the received hid descriptor is smaller than
> > the size of the struct hid_descriptor, it is possible to cause
> > out-of-bounds.
> >
> > In addition, if bNumDescriptors of the hid descriptor have an incorrect
> > value, this can also cause out-of-bounds while approaching hdesc->desc[n].
> >
> > So check the size of hid descriptor and bNumDescriptors.
> >
> > BUG: KASAN: slab-out-of-bounds in usbhid_parse+0x9b1/0xa20
> > Read of size 1 at addr ffff88006c5f8edf by task kworker/1:2/1261
> >
> > CPU: 1 PID: 1261 Comm: kworker/1:2 Not tainted
> > 4.14.0-rc1-42251-gebb2c2437d80 #169
> > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> > Workqueue: usb_hub_wq hub_event
> > Call Trace:
> > __dump_stack lib/dump_stack.c:16
> > dump_stack+0x292/0x395 lib/dump_stack.c:52
> > print_address_description+0x78/0x280 mm/kasan/report.c:252
> > kasan_report_error mm/kasan/report.c:351
> > kasan_report+0x22f/0x340 mm/kasan/report.c:409
> > __asan_report_load1_noabort+0x19/0x20 mm/kasan/report.c:427
> > usbhid_parse+0x9b1/0xa20 drivers/hid/usbhid/hid-core.c:1004
> > hid_add_device+0x16b/0xb30 drivers/hid/hid-core.c:2944
> > usbhid_probe+0xc28/0x1100 drivers/hid/usbhid/hid-core.c:1369
> > 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
> >
> > Reported-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx>
> > Signed-off-by: Jaejoong Kim <climbbb.kim@xxxxxxxxx>
> > ---
> >
> > Changes in v2:
> > - write a new commit message because orginal version is wrong approach
> > - add check hid descriptor size
> > - get proper value for bNumDescriptors as suggested by Alan Stern
> > - fix the Reported-by
> >
> > drivers/hid/usbhid/hid-core.c | 12 +++++++++++-
> > 1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
> > index 089bad8..045b5da 100644
> > --- a/drivers/hid/usbhid/hid-core.c
> > +++ b/drivers/hid/usbhid/hid-core.c
> > @@ -975,6 +975,8 @@ static int usbhid_parse(struct hid_device *hid)
> > unsigned int rsize = 0;
> > char *rdesc;
> > int ret, n;
> > + int num_descriptors;
> > + size_t offset = offsetof(struct hid_descriptor, desc);
> >
> > quirks = usbhid_lookup_quirk(le16_to_cpu(dev->descriptor.idVendor),
> > le16_to_cpu(dev->descriptor.idProduct));
> > @@ -997,10 +999,18 @@ static int usbhid_parse(struct hid_device *hid)
> > return -ENODEV;
> > }
> >
> > + if (hdesc->bLength < sizeof(struct hid_descriptor)) {
> > + dbg_hid("hid descriptor is too short\n");
> > + return -EINVAL;
> > + }
> > +
> > hid->version = le16_to_cpu(hdesc->bcdHID);
> > hid->country = hdesc->bCountryCode;
> >
> > - for (n = 0; n < hdesc->bNumDescriptors; n++)
> > + num_descriptors = min_t(int, hdesc->bNumDescriptors,
> > + (hdesc->bLength - offset) / sizeof(struct hid_class_descriptor));
> > +
> > + for (n = 0; n < num_descriptors; n++)
> > if (hdesc->desc[n].bDescriptorType == HID_DT_REPORT)
> > rsize = le16_to_cpu(hdesc->desc[n].wDescriptorLength);

Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>