This is a note to let you know that I've just added the patch titled
USB: cypress_m8: fix use-after-free in TIOCMIWAIT
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 356050d8b1e526db093e9d2c78daf49d6bf418e3 Mon Sep 17 00:00:00 2001
From: Johan Hovold <[email protected]>
Date: Tue, 19 Mar 2013 09:21:13 +0100
Subject: USB: cypress_m8: fix use-after-free in TIOCMIWAIT
Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.
This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.
Also remove bogus test for private data pointer being NULL as it is
never assigned in the loop.
Cc: stable <[email protected]>
Signed-off-by: Johan Hovold <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/usb/serial/cypress_m8.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 8efa19d..ba7352e 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -111,7 +111,6 @@ struct cypress_private {
int baud_rate; /* stores current baud rate in
integer form */
int isthrottled; /* if throttled, discard reads */
- wait_queue_head_t delta_msr_wait; /* used for TIOCMIWAIT */
char prev_status, diff_status; /* used for TIOCMIWAIT */
/* we pass a pointer to this as the argument sent to
cypress_set_termios old_termios */
@@ -449,7 +448,6 @@ static int cypress_generic_port_probe(struct
usb_serial_port *port)
kfree(priv);
return -ENOMEM;
}
- init_waitqueue_head(&priv->delta_msr_wait);
usb_reset_configuration(serial->dev);
@@ -868,12 +866,16 @@ static int cypress_ioctl(struct tty_struct *tty,
switch (cmd) {
/* This code comes from drivers/char/serial.c and ftdi_sio.c */
case TIOCMIWAIT:
- while (priv != NULL) {
- interruptible_sleep_on(&priv->delta_msr_wait);
+ for (;;) {
+ interruptible_sleep_on(&port->delta_msr_wait);
/* see if a signal did it */
if (signal_pending(current))
return -ERESTARTSYS;
- else {
+
+ if (port->serial->disconnected)
+ return -EIO;
+
+ {
char diff = priv->diff_status;
if (diff == 0)
return -EIO; /* no change => error */
@@ -1187,7 +1189,7 @@ static void cypress_read_int_callback(struct urb *urb)
if (priv->current_status != priv->prev_status) {
priv->diff_status |= priv->current_status ^
priv->prev_status;
- wake_up_interruptible(&priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
priv->prev_status = priv->current_status;
}
spin_unlock_irqrestore(&priv->lock, flags);
--
1.8.0.rc0.18.gf84667d
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