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Bluetooth: Take proper tty_struct references 

In net/bluetooth/rfcomm/tty.c the struct tty_struct is used without
taking references. This may lead to a use-after-free of the rfcomm tty.

Fix this by taking references properly, using the tty_port_* helpers
when possible.

The raw assignments of dev->port.tty in rfcomm_tty_open/close are
addressed in the later commit 'rfcomm: Implement .activate, .shutdown
and .carrier_raised methods'.

Signed-off-by: Gianluca Anzolin <gianluca@sottospazio.it>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
This commit is contained in:
Gianluca Anzolin 2013-07-29 17:08:08 +02:00 committed by Gustavo Padovan
parent c7882cbd11
commit 396dc223dd
1 changed files with 17 additions and 12 deletions
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29
net/bluetooth/rfcomm/tty.c
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@ -333,10 +333,9 @@ static inline unsigned int rfcomm_room(struct rfcomm_dlc *dlc)
static void rfcomm_wfree(struct sk_buff *skb)
{
struct rfcomm_dev *dev = (void *) skb->sk;
struct tty_struct *tty = dev->port.tty;
atomic_sub(skb->truesize, &dev->wmem_alloc);
if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags) && tty)
tty_wakeup(tty);
if (test_bit(RFCOMM_TTY_ATTACHED, &dev->flags))
tty_port_tty_wakeup(&dev->port);
tty_port_put(&dev->port);
}
@ -410,6 +409,7 @@ static int rfcomm_release_dev(void __user *arg)
{
struct rfcomm_dev_req req;
struct rfcomm_dev *dev;
struct tty_struct *tty;
if (copy_from_user(&req, arg, sizeof(req)))
return -EFAULT;
@ -429,8 +429,11 @@ static int rfcomm_release_dev(void __user *arg)
rfcomm_dlc_close(dev->dlc, 0);
/* Shut down TTY synchronously before freeing rfcomm_dev */
if (dev->port.tty)
tty_vhangup(dev->port.tty);
tty = tty_port_tty_get(&dev->port);
if (tty) {
tty_vhangup(tty);
tty_kref_put(tty);
}
if (!test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags))
rfcomm_dev_del(dev);
@ -563,6 +566,7 @@ static void rfcomm_dev_data_ready(struct rfcomm_dlc *dlc, struct sk_buff *skb)
static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
{
struct rfcomm_dev *dev = dlc->owner;
struct tty_struct *tty;
if (!dev)
return;
@ -572,7 +576,8 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
wake_up_interruptible(&dev->wait);
if (dlc->state == BT_CLOSED) {
if (!dev->port.tty) {
tty = tty_port_tty_get(&dev->port);
if (!tty) {
if (test_bit(RFCOMM_RELEASE_ONHUP, &dev->flags)) {
/* Drop DLC lock here to avoid deadlock
* 1. rfcomm_dev_get will take rfcomm_dev_lock
@ -591,8 +596,10 @@ static void rfcomm_dev_state_change(struct rfcomm_dlc *dlc, int err)
tty_port_put(&dev->port);
rfcomm_dlc_lock(dlc);
}
} else
tty_hangup(dev->port.tty);
} else {
tty_hangup(tty);
tty_kref_put(tty);
}
}
}
@ -604,10 +611,8 @@ static void rfcomm_dev_modem_status(struct rfcomm_dlc *dlc, u8 v24_sig)
BT_DBG("dlc %p dev %p v24_sig 0x%02x", dlc, dev, v24_sig);
if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV)) {
if (dev->port.tty && !C_CLOCAL(dev->port.tty))
tty_hangup(dev->port.tty);
}
if ((dev->modem_status & TIOCM_CD) && !(v24_sig & RFCOMM_V24_DV))
tty_port_tty_hangup(&dev->port, true);
dev->modem_status =
((v24_sig & RFCOMM_V24_RTC) ? (TIOCM_DSR | TIOCM_DTR) : 0) |