diff options
| author | Konstantin Khlebnikov <khlebnikov@openvz.org> | 2012-01-05 13:04:21 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-24 13:56:10 -0800 |
| commit | 593a27c4b212e2afdf772a1f8dcb894e91bda0fa (patch) | |
| tree | 6b670f6ec0ef138fcfa6e68f3b2a456f86941efd /drivers | |
| parent | dcd6c92267155e70a94b3927bce681ce74b80d1f (diff) | |
tty: cleanup prohibition of direct opening for unix98 pty master
cleanup hack added in v2.6.27-3203-g15582d3
comment from that patch:
: pty: If the administrator creates a device for a ptmx slave we should not error
:
: The open path for ptmx slaves is via the ptmx device. Opening them any
: other way is not allowed. Vegard Nossum found that previously this was not
: the case and mknod foo c 128 42; cat foo would produce nasty diagnostics
:
: Signed-off-by: Alan Cox <alan@redhat.com>
: Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
devpts_get_tty() returns non-null only for inodes on devpts, but there is no
inodes for master-devices, /dev/ptmx (/dev/pts/ptmx) is the only way to open them.
Thus we can completely forbid lookup for master-devices and eliminate that hack in
tty_init_dev() because tty_open() will get EIO from tty_driver_lookup_tty().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/tty/pty.c | 8 | ||||
| -rw-r--r-- | drivers/tty/tty_io.c | 12 |
2 files changed, 5 insertions, 15 deletions
diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c index d8653ab6f49..03147fa31d4 100644 --- a/drivers/tty/pty.c +++ b/drivers/tty/pty.c @@ -515,10 +515,8 @@ static int pty_unix98_ioctl(struct tty_struct *tty, static struct tty_struct *ptm_unix98_lookup(struct tty_driver *driver, struct inode *ptm_inode, int idx) { - struct tty_struct *tty = devpts_get_tty(ptm_inode, idx); - if (tty) - tty = tty->link; - return tty; + /* Master must be open via /dev/ptmx */ + return ERR_PTR(-EIO); } /** @@ -677,7 +675,7 @@ static int ptmx_open(struct inode *inode, struct file *filp) mutex_lock(&tty_mutex); tty_lock(); - tty = tty_init_dev(ptm_driver, index, 1); + tty = tty_init_dev(ptm_driver, index); mutex_unlock(&tty_mutex); if (IS_ERR(tty)) { diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index e41b9bbc107..fbcc1406380 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -1365,7 +1365,6 @@ static int tty_reopen(struct tty_struct *tty) * @driver: tty driver we are opening a device on * @idx: device index * @ret_tty: returned tty structure - * @first_ok: ok to open a new device (used by ptmx) * * Prepare a tty device. This may not be a "new" clean device but * could also be an active device. The pty drivers require special @@ -1385,18 +1384,11 @@ static int tty_reopen(struct tty_struct *tty) * relaxed for the (most common) case of reopening a tty. */ -struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx, - int first_ok) +struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx) { struct tty_struct *tty; int retval; - /* Check if pty master is being opened multiple times */ - if (driver->subtype == PTY_TYPE_MASTER && - (driver->flags & TTY_DRIVER_DEVPTS_MEM) && !first_ok) { - return ERR_PTR(-EIO); - } - /* * First time open is complex, especially for PTY devices. * This code guarantees that either everything succeeds and the @@ -1950,7 +1942,7 @@ retry_open: if (retval) tty = ERR_PTR(retval); } else - tty = tty_init_dev(driver, index, 0); + tty = tty_init_dev(driver, index); mutex_unlock(&tty_mutex); if (driver) |