From b9d711c45a310cd150bddced2604a70115059c2b Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 31 Jan 2017 17:17:29 +0100 Subject: [PATCH] USB: serial: keyspan_pda: fix receive sanity checks commit c528fcb116e61afc379a2e0a0f70906b937f1e2c upstream. Make sure to check for short transfers before parsing the receive buffer to avoid acting on stale data. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reviewed-by: Greg Kroah-Hartman Signed-off-by: Johan Hovold [bwh: Backported to 3.2: - Adjust context - Keep the check for !tty in the data case] Signed-off-by: Ben Hutchings --- drivers/usb/serial/keyspan_pda.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c index 65a090660e73..611904f1650c 100644 --- a/drivers/usb/serial/keyspan_pda.c +++ b/drivers/usb/serial/keyspan_pda.c @@ -212,6 +212,7 @@ static void keyspan_pda_rx_interrupt(struct urb *urb) struct usb_serial_port *port = urb->context; struct tty_struct *tty; unsigned char *data = urb->transfer_buffer; + unsigned int len = urb->actual_length; int retval; int status = urb->status; struct keyspan_pda_private *priv; @@ -234,20 +235,28 @@ static void keyspan_pda_rx_interrupt(struct urb *urb) goto exit; } + if (len < 1) { + dev_warn(&port->dev, "short message received\n"); + goto exit; + } + /* see if the message is data or a status interrupt */ switch (data[0]) { case 0: tty = tty_port_tty_get(&port->port); /* rest of message is rx data */ - if (tty && urb->actual_length) { - tty_insert_flip_string(tty, data + 1, - urb->actual_length - 1); - tty_flip_buffer_push(tty); - } + if (!tty || len < 2) + break; + tty_insert_flip_string(tty, data + 1, len - 1); + tty_flip_buffer_push(tty); tty_kref_put(tty); break; case 1: /* status interrupt */ + if (len < 3) { + dev_warn(&port->dev, "short interrupt message received\n"); + break; + } dbg(" rx int, d1=%d, d2=%d", data[1], data[2]); switch (data[1]) { case 1: /* modemline change */ -- 2.30.2