1 files changed, 34 insertions, 9 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index cf6e0f2e1331..396344cb011f 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -162,6 +162,17 @@ static inline int tty_put_user(struct tty_struct *tty, unsigned char x,
 	return put_user(x, ptr);
 }
 
+static inline int tty_copy_to_user(struct tty_struct *tty,
+					void __user *to,
+					const void *from,
+					unsigned long n)
+{
+	struct n_tty_data *ldata = tty->disc_data;
+
+	tty_audit_add_data(tty, to, n, ldata->icanon);
+	return copy_to_user(to, from, n);
+}
+
 /**
  *	n_tty_kick_worker - start input worker (if required)
  *	@tty: terminal
@@ -1949,6 +1960,18 @@ static inline int input_available_p(struct tty_struct *tty, int poll)
 		return ldata->commit_head - ldata->read_tail >= amt;
 }
 
+static inline int check_other_done(struct tty_struct *tty)
+{
+	int done = test_bit(TTY_OTHER_DONE, &tty->flags);
+	if (done) {
+		/* paired with cmpxchg() in check_other_closed(); ensures
+		 * read buffer head index is not stale
+		 */
+		smp_mb__after_atomic();
+	}
+	return done;
+}
+
 /**
  *	copy_from_read_buf	-	copy read data directly
  *	@tty: terminal device
@@ -2058,8 +2081,8 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
 
 	size = N_TTY_BUF_SIZE - tail;
 	n = eol - tail;
-	if (n > 4096)
-		n += 4096;
+	if (n > N_TTY_BUF_SIZE)
+		n += N_TTY_BUF_SIZE;
 	n += found;
 	c = n;
 
@@ -2072,12 +2095,12 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
 		    __func__, eol, found, n, c, size, more);
 
 	if (n > size) {
-		ret = copy_to_user(*b, read_buf_addr(ldata, tail), size);
+		ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), size);
 		if (ret)
 			return -EFAULT;
-		ret = copy_to_user(*b + size, ldata->read_buf, n - size);
+		ret = tty_copy_to_user(tty, *b + size, ldata->read_buf, n - size);
 	} else
-		ret = copy_to_user(*b, read_buf_addr(ldata, tail), n);
+		ret = tty_copy_to_user(tty, *b, read_buf_addr(ldata, tail), n);
 
 	if (ret)
 		return -EFAULT;
@@ -2167,7 +2190,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 	struct n_tty_data *ldata = tty->disc_data;
 	unsigned char __user *b = buf;
 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int c;
+	int c, done;
 	int minimum, time;
 	ssize_t retval = 0;
 	long timeout;
@@ -2235,8 +2258,10 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 		    ((minimum - (b - buf)) >= 1))
 			ldata->minimum_to_wake = (minimum - (b - buf));
 
+		done = check_other_done(tty);
+
 		if (!input_available_p(tty, 0)) {
-			if (test_bit(TTY_OTHER_CLOSED, &tty->flags)) {
+			if (done) {
 				retval = -EIO;
 				break;
 			}
@@ -2443,12 +2468,12 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
 
 	poll_wait(file, &tty->read_wait, wait);
 	poll_wait(file, &tty->write_wait, wait);
+	if (check_other_done(tty))
+		mask |= POLLHUP;
 	if (input_available_p(tty, 1))
 		mask |= POLLIN | POLLRDNORM;
 	if (tty->packet && tty->link->ctrl_status)
 		mask |= POLLPRI | POLLIN | POLLRDNORM;
-	if (test_bit(TTY_OTHER_CLOSED, &tty->flags))
-		mask |= POLLHUP;
 	if (tty_hung_up_p(file))
 		mask |= POLLHUP;
 	if (!(mask & (POLLHUP | POLLIN | POLLRDNORM))) {