Re: [PATCH 2/2] Check tcsetpgrp p is a process group.

From: Greg Kroah-Hartman
Date: Sat Jun 27 2015 - 19:27:16 EST


On Sat, Jun 27, 2015 at 05:17:03PM -0400, Patrick Donnelly wrote:
> This fixes a bug where a process can set the foreground process group to its
> pid even if its pid is not a valid pgrp.
>
> Signed-off-by: Patrick Donnelly <batrick@xxxxxxxxxxxx>
> ---
> drivers/tty/tty_io.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
> index 401d05e..c20a2fb 100644
> --- a/drivers/tty/tty_io.c
> +++ b/drivers/tty/tty_io.c
> @@ -2560,9 +2560,11 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
> {
> struct pid *pgrp;
> pid_t pgrp_nr;
> - int retval = tty_check_change(real_tty);
> + int retval;
> unsigned long flags;
>
> + retval = tty_check_change(real_tty);
> +
> if (retval == -EIO)
> return -ENOTTY;
> if (retval)
> @@ -2580,6 +2582,10 @@ static int tiocspgrp(struct tty_struct *tty, struct tty_struct *real_tty, pid_t
> retval = -ESRCH;
> if (!pgrp)
> goto out_unlock;
> + retval = -EINVAL;
> + if (!pid_task(pgrp, PIDTYPE_PGID)) {
> + goto out_unlock;
> + }
> retval = -EPERM;
> if (session_of_pgrp(pgrp) != task_session(current))
> goto out_unlock;

Always run your patches though checkpatch.pl so you don't get emails
telling you to fix the things that checkpatch.pl tells you to...
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