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[6/7] HID: lenovo-tpkbd: validate output report details

Message ID 1378312645-27736-7-git-send-email-keescook@chromium.org (mailing list archive)
State New, archived
Delegated to: Jiri Kosina
Headers show

Commit Message

Kees Cook Sept. 4, 2013, 4:37 p.m. UTC
A HID device could send a malicious output report that would cause the
lenovo-tpkbd HID driver to write just beyond the output report allocation
during initialization, causing a heap overflow:

[   76.109807] usb 1-1: New USB device found, idVendor=17ef, idProduct=6009
...
[   80.462540] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten

CVE-2013-2894

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@kernel.org
---
 drivers/hid/hid-lenovo-tpkbd.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Benjamin Tissoires Sept. 9, 2013, 1:28 p.m. UTC | #1
On Wed, Sep 4, 2013 at 6:37 PM, Kees Cook <keescook@chromium.org> wrote:
> A HID device could send a malicious output report that would cause the
> lenovo-tpkbd HID driver to write just beyond the output report allocation
> during initialization, causing a heap overflow:
>
> [   76.109807] usb 1-1: New USB device found, idVendor=17ef, idProduct=6009
> ...
> [   80.462540] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten
>
> CVE-2013-2894
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> Cc: stable@kernel.org
> ---

As mentioned by Josh on the previous thread, this patch triggers a bug
for the users:
https://bugzilla.redhat.com/show_bug.cgi?id=1003998

I am writing the comments I have given the bug:

>  drivers/hid/hid-lenovo-tpkbd.c |   10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-lenovo-tpkbd.c b/drivers/hid/hid-lenovo-tpkbd.c
> index 07837f5..f458e76 100644
> --- a/drivers/hid/hid-lenovo-tpkbd.c
> +++ b/drivers/hid/hid-lenovo-tpkbd.c
> @@ -339,7 +339,15 @@ static int tpkbd_probe_tp(struct hid_device *hdev)
>         struct tpkbd_data_pointer *data_pointer;
>         size_t name_sz = strlen(dev_name(dev)) + 16;
>         char *name_mute, *name_micmute;
> -       int ret;
> +       int i, ret;
> +
> +       /* Validate required reports. */
> +       for (i = 0; i < 4; i++) {
> +               if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, 4, i, 1))

The report descriptor shows that the report ID 4 is a FEATURE, not an OUTPUT.

> +                       return -ENODEV;

There is a problem in the probe() function when tpkbd_probe_tp()
fails: it directly bails out instead of calling hid_hw_stop(), thus,
the input devices are still there while nobody has a pointer to them.
This way, ODEBUG is triggered. But this should be address in an other
patch I would say.

Cheers,
Benjamin

> +       }
> +       if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, 3, 0, 2))
> +               return -ENODEV;
>
>         if (sysfs_create_group(&hdev->dev.kobj,
>                                 &tpkbd_attr_group_pointer)) {
> --
> 1.7.9.5
>
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diff mbox

Patch

diff --git a/drivers/hid/hid-lenovo-tpkbd.c b/drivers/hid/hid-lenovo-tpkbd.c
index 07837f5..f458e76 100644
--- a/drivers/hid/hid-lenovo-tpkbd.c
+++ b/drivers/hid/hid-lenovo-tpkbd.c
@@ -339,7 +339,15 @@  static int tpkbd_probe_tp(struct hid_device *hdev)
 	struct tpkbd_data_pointer *data_pointer;
 	size_t name_sz = strlen(dev_name(dev)) + 16;
 	char *name_mute, *name_micmute;
-	int ret;
+	int i, ret;
+
+	/* Validate required reports. */
+	for (i = 0; i < 4; i++) {
+		if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, 4, i, 1))
+			return -ENODEV;
+	}
+	if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, 3, 0, 2))
+		return -ENODEV;
 
 	if (sysfs_create_group(&hdev->dev.kobj,
 				&tpkbd_attr_group_pointer)) {