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authorJia-Ju Bai <baijiaju1990@gmail.com>2019-01-08 21:04:48 +0800
committerDavid S. Miller <davem@davemloft.net>2019-01-11 17:56:47 -0800
commit2ff33d6637393fe9348357285931811b76e1402f (patch)
treef6090d0aa33f29b60ad0460e63e9916c7a0997a2 /drivers/isdn
parent7fbe078c37aba3088359c9256c1a1d0c3e39ee81 (diff)
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isdn: i4l: isdn_tty: Fix some concurrency double-free bugs
The functions isdn_tty_tiocmset() and isdn_tty_set_termios() may be concurrently executed. isdn_tty_tiocmset isdn_tty_modem_hup line 719: kfree(info->dtmf_state); line 721: kfree(info->silence_state); line 723: kfree(info->adpcms); line 725: kfree(info->adpcmr); isdn_tty_set_termios isdn_tty_modem_hup line 719: kfree(info->dtmf_state); line 721: kfree(info->silence_state); line 723: kfree(info->adpcms); line 725: kfree(info->adpcmr); Thus, some concurrency double-free bugs may occur. These possible bugs are found by a static tool written by myself and my manual code review. To fix these possible bugs, the mutex lock "modem_info_mutex" used in isdn_tty_tiocmset() is added in isdn_tty_set_termios(). Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn')
-rw-r--r--drivers/isdn/i4l/isdn_tty.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index 1b2239c1d569..dc1cded716c1 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -1437,15 +1437,19 @@ isdn_tty_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
modem_info *info = (modem_info *) tty->driver_data;
+ mutex_lock(&modem_info_mutex);
if (!old_termios)
isdn_tty_change_speed(info);
else {
if (tty->termios.c_cflag == old_termios->c_cflag &&
tty->termios.c_ispeed == old_termios->c_ispeed &&
- tty->termios.c_ospeed == old_termios->c_ospeed)
+ tty->termios.c_ospeed == old_termios->c_ospeed) {
+ mutex_unlock(&modem_info_mutex);
return;
+ }
isdn_tty_change_speed(info);
}
+ mutex_unlock(&modem_info_mutex);
}
/*