[PATCH v3 02/10] HID: zeroplus: validate output report details

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

From: Kees Cook <keescook@chromium.org>

The zeroplus HID driver was not checking the size of allocated values
in fields it used. A HID device could send a malicious output report
that would cause the driver to write beyond the output report allocation
during initialization, causing a heap overflow:

[ 1442.728680] usb 1-1: New USB device found, idVendor=0c12, idProduct=0005
...
[ 1466.243173] BUG kmalloc-192 (Tainted: G        W   ): Redzone overwritten

CVE-2013-2889

Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
---
v3:
 - no changes

 drivers/hid/hid-zpff.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/hid/hid-zpff.c b/drivers/hid/hid-zpff.c
index 6ec28a3..a29756c 100644
--- a/drivers/hid/hid-zpff.c
+++ b/drivers/hid/hid-zpff.c
@@ -68,21 +68,13 @@ static int zpff_init(struct hid_device *hid)
 	struct hid_report *report;
 	struct hid_input *hidinput = list_entry(hid->inputs.next,
 						struct hid_input, list);
-	struct list_head *report_list =
-			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
 	struct input_dev *dev = hidinput->input;
-	int error;
+	int i, error;
 
-	if (list_empty(report_list)) {
-		hid_err(hid, "no output report found\n");
-		return -ENODEV;
-	}
-
-	report = list_entry(report_list->next, struct hid_report, list);
-
-	if (report->maxfield < 4) {
-		hid_err(hid, "not enough fields in report\n");
-		return -ENODEV;
+	for (i = 0; i < 4; i++) {
+		report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, i, 1);
+		if (!report)
+			return -ENODEV;
 	}
 
 	zpff = kzalloc(sizeof(struct zpff_device), GFP_KERNEL);
-- 
1.8.3.1