Patch "[media] ttusb2: limit messages to buffer size" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

[media] ttusb2: limit messages to buffer size

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ttusb2-limit-messages-to-buffer-size.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Alyssa Milburn <[email protected]>
Date: Sat, 1 Apr 2017 14:34:32 -0300
Subject: [media] ttusb2: limit messages to buffer size

From: Alyssa Milburn <[email protected]>

commit a12b8ab8c5ff7ccd7b107a564743507c850a441d upstream.

Otherwise ttusb2_i2c_xfer can read or write beyond the end of static and heap buffers.

---
 drivers/media/usb/dvb-usb/ttusb2.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

@@ -78,6 +78,9 @@ static int ttusb2_msg(struct dvb_usb_dev
 	u8 *s, *r = NULL;
 	int ret = 0;
 
+	if (4 + rlen > 64)
+		return -EIO;
+
 	s = kzalloc(wlen+4, GFP_KERNEL);
 	if (!s)
 		return -ENOMEM;

@@ -381,6 +384,22 @@ static int ttusb2_i2c_xfer(struct i2c_ad
 		write_read = i+1 < num && (msg[i+1].flags & I2C_M_RD);
 		read = msg[i].flags & I2C_M_RD;
 
+		if (3 + msg[i].len > sizeof(obuf)) {
+			err("i2c wr len=%d too high", msg[i].len);
+			break;
+		}
+		if (write_read) {
+			if (3 + msg[i+1].len > sizeof(ibuf)) {
+				err("i2c rd len=%d too high", msg[i+1].len);
+				break;
+			}
+		} else if (read) {
+			if (3 + msg[i].len > sizeof(ibuf)) {
+				err("i2c rd len=%d too high", msg[i].len);
+				break;
+			}
+		}
+
 		obuf[0] = (msg[i].addr << 1) | (write_read | read);
 		if (read)
 			obuf[1] = 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/ttusb2-limit-messages-to-buffer-size.patch