Re: [PATCH] tty: cleanup prohibition of direct opening for unix98pty master

From: Konstantin Khlebnikov
Date: Thu Jan 05 2012 - 04:13:19 EST


Greg KH wrote:
On Tue, Jan 03, 2012 at 12:51:11PM +0400, Konstantin Khlebnikov wrote:
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@xxxxxxxxxx>
: Signed-off-by: Linus Torvalds<torvalds@xxxxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxx>

What tree did you make this patch against? I get fuzz warnings when
applying it to the tty-next branch (it's in the linux-next releases).

Please rediff it and resend it.

Sorry for that, I did not expect such activity in tty-layer =)


thanks,

greg k-h

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/