From 9f12e37cae44a96132fc3031535a0b165486941a Mon Sep 17 00:00:00 2001 From: Sami Tolvanen Date: Mon, 25 Jan 2021 11:09:25 -0800 Subject: 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 Signed-off-by: Linus Torvalds --- drivers/tty/n_tty.c | 7 ++----- drivers/tty/tty_io.c | 2 -- include/linux/tty.h | 1 + 3 files changed, 3 insertions(+), 7 deletions(-) diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index 319d68c8a5df..219e85756171 100644 --- 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 4a208a95e921..48de20916ca7 100644 --- 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 c873f475f0a7..37803f3e6d49 100644 --- 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) { } -- cgit v1.2.3