Commit 9bb48c82aced ("tty: implement write_iter") converted the tty

layer to use write_iter. Fix the redirected_tty_write declaration
also in n_tty and change the comparisons to use write_iter instead of
write.

[ Also moved the declaration of redirected_tty_write() to the proper
  location in a header file. The reason for the bug was the bogus extern
  declaration in n_tty.c silently not matching the changed definition in
  tty_io.c, and because it wasn't in a shared header file, there was no
  cross-checking of the declaration.

  Sami noticed because Clang's Control Flow Integrity checking ended up
  incidentally noticing the inconsistent declaration.    - Linus ]

Fixes: 9bb48c82aced ("tty: implement write_iter")
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 319d68c8a5df32b62eb7fec1e7f518910f971ea0..219e85756171be8ecd75132001271252c2d28ac9 100644 (file)
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2081,9 +2081,6 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
        return 0;
 }
 
-extern ssize_t redirected_tty_write(struct file *, const char __user *,
-                                                       size_t, loff_t *);
-
 /**
  *     job_control             -       check job control
  *     @tty: tty
@@ -2105,7 +2102,7 @@ static int job_control(struct tty_struct *tty, struct file *file)
        /* NOTE: not yet done after every sleep pending a thorough
           check of the logic of this change. -- jlc */
        /* don't stop on /dev/console */
-       if (file->f_op->write == redirected_tty_write)
+       if (file->f_op->write_iter == redirected_tty_write)
                return 0;
 
        return __tty_check_change(tty, SIGTTIN);
@@ -2309,7 +2306,7 @@ static ssize_t n_tty_write(struct tty_struct *tty, struct file *file,
        ssize_t retval = 0;
 
        /* Job control check -- must be done at start (POSIX.1 7.1.1.4). */
-       if (L_TOSTOP(tty) && file->f_op->write != redirected_tty_write) {
+       if (L_TOSTOP(tty) && file->f_op->write_iter != redirected_tty_write) {
                retval = tty_check_change(tty);
                if (retval)
                        return retval;

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 4a208a95e9219ba34f6b539d0e84af2d9556ea69..48de20916ca7841938e7434caf6125809fae9536 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -144,10 +144,8 @@ DEFINE_MUTEX(tty_mutex);
 
 static ssize_t tty_read(struct file *, char __user *, size_t, loff_t *);
 static ssize_t tty_write(struct kiocb *, struct iov_iter *);
-ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
 static __poll_t tty_poll(struct file *, poll_table *);
 static int tty_open(struct inode *, struct file *);
-long tty_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
 #ifdef CONFIG_COMPAT
 static long tty_compat_ioctl(struct file *file, unsigned int cmd,
                                unsigned long arg);

diff --git a/include/linux/tty.h b/include/linux/tty.h
index c873f475f0a762da8205c7cb4be684d5a1cd5677..37803f3e6d49eb7581e7168ea9807d351bf29fe2 100644 (file)
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -421,6 +421,7 @@ extern void tty_kclose(struct tty_struct *tty);
 extern int tty_dev_name_to_number(const char *name, dev_t *number);
 extern int tty_ldisc_lock(struct tty_struct *tty, unsigned long timeout);
 extern void tty_ldisc_unlock(struct tty_struct *tty);
+extern ssize_t redirected_tty_write(struct kiocb *, struct iov_iter *);
 #else
 static inline void tty_kref_put(struct tty_struct *tty)
 { }