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| author | Jia-Ju Bai <baijiaju1990@gmail.com> | 2019-01-08 21:04:48 +0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-11 17:56:47 -0800 |
| commit | 2ff33d6637393fe9348357285931811b76e1402f (patch) | |
| tree | f6090d0aa33f29b60ad0460e63e9916c7a0997a2 /drivers/isdn | |
| parent | 7fbe078c37aba3088359c9256c1a1d0c3e39ee81 (diff) | |
| download | linux-stable-2ff33d6637393fe9348357285931811b76e1402f.tar.gz linux-stable-2ff33d6637393fe9348357285931811b76e1402f.tar.bz2 linux-stable-2ff33d6637393fe9348357285931811b76e1402f.zip | |
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.c | 6 |
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); } /* |