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path: root/drivers/char/tty_ioctl.c
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Diffstat (limited to 'drivers/char/tty_ioctl.c')
-rw-r--r--drivers/char/tty_ioctl.c88
1 files changed, 59 insertions, 29 deletions
diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 6f4c7d0a53b..8116bb1c8f8 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -97,14 +97,19 @@ EXPORT_SYMBOL(tty_driver_flush_buffer);
* @tty: terminal
*
* Indicate that a tty should stop transmitting data down the stack.
+ * Takes the termios mutex to protect against parallel throttle/unthrottle
+ * and also to ensure the driver can consistently reference its own
+ * termios data at this point when implementing software flow control.
*/
void tty_throttle(struct tty_struct *tty)
{
+ mutex_lock(&tty->termios_mutex);
/* check TTY_THROTTLED first so it indicates our state */
if (!test_and_set_bit(TTY_THROTTLED, &tty->flags) &&
tty->ops->throttle)
tty->ops->throttle(tty);
+ mutex_unlock(&tty->termios_mutex);
}
EXPORT_SYMBOL(tty_throttle);
@@ -113,13 +118,21 @@ EXPORT_SYMBOL(tty_throttle);
* @tty: terminal
*
* Indicate that a tty may continue transmitting data down the stack.
+ * Takes the termios mutex to protect against parallel throttle/unthrottle
+ * and also to ensure the driver can consistently reference its own
+ * termios data at this point when implementing software flow control.
+ *
+ * Drivers should however remember that the stack can issue a throttle,
+ * then change flow control method, then unthrottle.
*/
void tty_unthrottle(struct tty_struct *tty)
{
+ mutex_lock(&tty->termios_mutex);
if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
tty->ops->unthrottle)
tty->ops->unthrottle(tty);
+ mutex_unlock(&tty->termios_mutex);
}
EXPORT_SYMBOL(tty_unthrottle);
@@ -613,9 +626,25 @@ static int set_termios(struct tty_struct *tty, void __user *arg, int opt)
return 0;
}
+static void copy_termios(struct tty_struct *tty, struct ktermios *kterm)
+{
+ mutex_lock(&tty->termios_mutex);
+ memcpy(kterm, tty->termios, sizeof(struct ktermios));
+ mutex_unlock(&tty->termios_mutex);
+}
+
+static void copy_termios_locked(struct tty_struct *tty, struct ktermios *kterm)
+{
+ mutex_lock(&tty->termios_mutex);
+ memcpy(kterm, tty->termios_locked, sizeof(struct ktermios));
+ mutex_unlock(&tty->termios_mutex);
+}
+
static int get_termio(struct tty_struct *tty, struct termio __user *termio)
{
- if (kernel_termios_to_user_termio(termio, tty->termios))
+ struct ktermios kterm;
+ copy_termios(tty, &kterm);
+ if (kernel_termios_to_user_termio(termio, &kterm))
return -EFAULT;
return 0;
}
@@ -917,6 +946,8 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
struct tty_struct *real_tty;
void __user *p = (void __user *)arg;
int ret = 0;
+ struct ktermios kterm;
+ struct termiox ktermx;
if (tty->driver->type == TTY_DRIVER_TYPE_PTY &&
tty->driver->subtype == PTY_TYPE_MASTER)
@@ -952,23 +983,20 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
return set_termios(real_tty, p, TERMIOS_OLD);
#ifndef TCGETS2
case TCGETS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
#else
case TCGETS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TCGETS2:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios2 __user *)arg, real_tty->termios))
+ copy_termios(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios2 __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TCSETSF2:
return set_termios(real_tty, p, TERMIOS_FLUSH | TERMIOS_WAIT);
@@ -987,34 +1015,36 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
return set_termios(real_tty, p, TERMIOS_TERMIO);
#ifndef TCGETS2
case TIOCGLCKTRMIOS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios((struct termios __user *)arg, real_tty->termios_locked))
+ copy_termios_locked(real_tty, &kterm);
+ if (kernel_termios_to_user_termios((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSLCKTRMIOS:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- mutex_lock(&real_tty->termios_mutex);
- if (user_termios_to_kernel_termios(real_tty->termios_locked,
+ copy_termios_locked(real_tty, &kterm);
+ if (user_termios_to_kernel_termios(&kterm,
(struct termios __user *) arg))
- ret = -EFAULT;
+ return -EFAULT;
+ mutex_lock(&real_tty->termios_mutex);
+ memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
mutex_unlock(&real_tty->termios_mutex);
- return ret;
+ return 0;
#else
case TIOCGLCKTRMIOS:
- mutex_lock(&real_tty->termios_mutex);
- if (kernel_termios_to_user_termios_1((struct termios __user *)arg, real_tty->termios_locked))
+ copy_termios_locked(real_tty, &kterm);
+ if (kernel_termios_to_user_termios_1((struct termios __user *)arg, &kterm))
ret = -EFAULT;
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSLCKTRMIOS:
if (!capable(CAP_SYS_ADMIN))
- ret = -EPERM;
- mutex_lock(&real_tty->termios_mutex);
- if (user_termios_to_kernel_termios_1(real_tty->termios_locked,
+ return -EPERM;
+ copy_termios_locked(real_tty, &kterm);
+ if (user_termios_to_kernel_termios_1(&kterm,
(struct termios __user *) arg))
- ret = -EFAULT;
+ return -EFAULT;
+ mutex_lock(&real_tty->termios_mutex);
+ memcpy(real_tty->termios_locked, &kterm, sizeof(struct ktermios));
mutex_unlock(&real_tty->termios_mutex);
return ret;
#endif
@@ -1023,9 +1053,10 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
if (real_tty->termiox == NULL)
return -EINVAL;
mutex_lock(&real_tty->termios_mutex);
- if (copy_to_user(p, real_tty->termiox, sizeof(struct termiox)))
- ret = -EFAULT;
+ memcpy(&ktermx, real_tty->termiox, sizeof(struct termiox));
mutex_unlock(&real_tty->termios_mutex);
+ if (copy_to_user(p, &ktermx, sizeof(struct termiox)))
+ ret = -EFAULT;
return ret;
case TCSETX:
return set_termiox(real_tty, p, 0);
@@ -1035,10 +1066,9 @@ int tty_mode_ioctl(struct tty_struct *tty, struct file *file,
return set_termiox(real_tty, p, TERMIOS_FLUSH);
#endif
case TIOCGSOFTCAR:
- mutex_lock(&real_tty->termios_mutex);
- ret = put_user(C_CLOCAL(real_tty) ? 1 : 0,
+ copy_termios(real_tty, &kterm);
+ ret = put_user((kterm.c_cflag & CLOCAL) ? 1 : 0,
(int __user *)arg);
- mutex_unlock(&real_tty->termios_mutex);
return ret;
case TIOCSSOFTCAR:
if (get_user(arg, (unsigned int __user *) arg))
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-04 19:06:14 +0000