Date:   Tue, 10 Oct 2017 16:25:45 +0900
From:   Jaejoong Kim <climbbb.kim@...il.com>
To:     Alan Stern <stern@...land.harvard.edu>,
        Jiri Kosina <jikos@...nel.org>,
        Andrey Konovalov <andreyknvl@...gle.com>
Cc:     Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        USB list <linux-usb@...r.kernel.org>,
        linux-input@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
        syzkaller <syzkaller@...glegroups.com>,
        Jaejoong Kim <climbbb.kim@...il.com>
Subject: Re: [PATCH v2] HID: usbhid: fix out-of-bounds bug

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@...il.com>:
> 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@...gle.com>
> Signed-off-by: Jaejoong Kim <climbbb.kim@...il.com>
> ---
>
> 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
>

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