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

From: Jaejoong Kim
Date: Tue Oct 10 2017 - 03:25:52 EST


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);
>
> --
> 2.7.4
>