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

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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@batbytes.com>
> ---
>  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;

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telling you to fix the things that checkpatch.pl tells you to...