HID: logitech-dj: validate output report details

A HID device could send a malicious output report that would cause the
logitech-dj HID driver to leak kernel memory contents to the device, or
trigger a NULL dereference during initialization:

[  304.424553] usb 1-1: New USB device found, idVendor=046d, idProduct=c52b
...
[  304.780467] BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
[  304.781409] IP: [<ffffffff815d50aa>] logi_dj_recv_send_report.isra.11+0x1a/0x90

CVE-2013-2895

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 8 insertions, 2 deletions

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 7800b1410562..2e5302462efb 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -461,7 +461,7 @@ static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
         struct hid_report *report;
         struct hid_report_enum *output_report_enum;
         u8 *data = (u8 *)(&dj_report->device_index);
-        int i;
+        unsigned int i;
 
         output_report_enum = &hdev->report_enum[HID_OUTPUT_REPORT];
         report = output_report_enum->report_id_hash[REPORT_ID_DJ_SHORT];
@@ -471,7 +471,7 @@ static int logi_dj_recv_send_report(struct dj_receiver_dev *djrcv_dev,
                 return -ENODEV;
         }
 
-        for (i = 0; i < report->field[0]->report_count; i++)
+        for (i = 0; i < DJREPORT_SHORT_LENGTH - 1; i++)
                 report->field[0]->value[i] = data[i];
 
         hid_hw_request(hdev, report, HID_REQ_SET_REPORT);
@@ -791,6 +791,12 @@ static int logi_dj_probe(struct hid_device *hdev,
                 goto hid_parse_fail;
         }
 
+        if (!hid_validate_values(hdev, HID_OUTPUT_REPORT, REPORT_ID_DJ_SHORT,
+                                 0, DJREPORT_SHORT_LENGTH - 1)) {
+                retval = -ENODEV;
+                goto hid_parse_fail;
+        }
+
         /* Starts the usb device and connects to upper interfaces hiddev and
          * hidraw */
         retval = hid_hw_start(hdev, HID_CONNECT_DEFAULT);