| Message ID | 20130207082449.GA18610@elgon.mountain (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
diff --git a/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c b/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c index 5b682cc..e407185 100644 --- a/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c +++ b/drivers/media/usb/ttusb-budget/dvb-ttusb-budget.c @@ -561,6 +561,13 @@ static void ttusb_process_muxpack(struct ttusb *ttusb, const u8 * muxpack, { u16 csum = 0, cc; int i; + + if (len < 4 || len & 0x1) { + pr_warn("%s: muxpack has invalid len %d\n", __func__, len); + numinvalid++; + return; + } + for (i = 0; i < len; i += 2) csum ^= le16_to_cpup((__le16 *) (muxpack + i)); if (csum) {
This patch is driven by a static checker warning. The ttusb_process_muxpack() function is only called from ttusb_process_frame(). Before calling, it verifies that len >= 2. The problem is that len == 2 is not valid and would lead to an array underflow. Odd number values for len are also invalid and would lead to reading past the end of the array. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- v2: Moved the check from the caller into the function. Added a check for odd values. Added an error message. Increment the numinvalid counter. -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html