HID: ntrig: validate feature report details

A HID device could send a malicious feature report that would cause the
ntrig HID driver to trigger a NULL dereference during initialization:

[57383.031190] usb 3-1: New USB device found, idVendor=1b96, idProduct=0001
...
[57383.315193] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
[57383.315308] IP: [<ffffffffa08102de>] ntrig_probe+0x25e/0x420 [hid_ntrig]

CVE-2013-2896

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@kernel.org
Signed-off-by: Rafi Rubin <rafi@seas.upenn.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/hid/hid-ntrig.c b/drivers/hid/hid-ntrig.c
index 98d1fdf7d8cd..600f2075512f 100644
--- a/drivers/hid/hid-ntrig.c
+++ b/drivers/hid/hid-ntrig.c
@@ -115,7 +115,8 @@ static inline int ntrig_get_mode(struct hid_device *hdev)
         struct hid_report *report = hdev->report_enum[HID_FEATURE_REPORT].
                                     report_id_hash[0x0d];
 
-        if (!report)
+        if (!report || report->maxfield < 1 ||
+            report->field[0]->report_count < 1)
                 return -EINVAL;
 
         hid_hw_request(hdev, report, HID_REQ_GET_REPORT);