[CRIU] [PATCH v2] files: Don't access value from stack in outer contex

[Andrei Vagin]

Applied, thanks!

On Thu, Jul 13, 2017 at 12:44:44AM +0300, Cyrill Gorcunov wrote:
> The struct fd_link link allocated in inner context might be
> freed before dump call (depending on compiler), instead
> use a safer approach.
> 
> Signed-off-by: Cyrill Gorcunov <gorcunov at virtuozzo.com>
> ---
>  criu/files.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
> 
> diff --git a/criu/files.c b/criu/files.c
> index a36eb366eb8f..8d1fb732ae72 100644
> --- a/criu/files.c
> +++ b/criu/files.c
> @@ -425,8 +425,11 @@ static const struct fdtype_ops *get_mem_dev_ops(struct fd_parms *p, int minor)
>  
>  static int dump_chrdev(struct fd_parms *p, int lfd, struct cr_img *img)
>  {
> +	struct fd_link *link_old = p->link;
>  	int maj = major(p->stat.st_rdev);
>  	const struct fdtype_ops *ops;
> +	struct fd_link link;
> +	int err;
>  
>  	switch (maj) {
>  	case MEM_MAJOR:
> @@ -441,8 +444,6 @@ static int dump_chrdev(struct fd_parms *p, int lfd, struct cr_img *img)
>  		char more[32];
>  
>  		if (is_tty(p->stat.st_rdev, p->stat.st_dev)) {
> -			struct fd_link link;
> -
>  			if (fill_fdlink(lfd, p, &link))
>  				return -1;
>  			p->link = &link;
> @@ -451,11 +452,15 @@ static int dump_chrdev(struct fd_parms *p, int lfd, struct cr_img *img)
>  		}
>  
>  		sprintf(more, "%d:%d", maj, minor(p->stat.st_rdev));
> -		return dump_unsupp_fd(p, lfd, img, "chr", more);
> +		err = dump_unsupp_fd(p, lfd, img, "chr", more);
> +		p->link = link_old;
> +		return err;
>  	}
>  	}
>  
> -	return do_dump_gen_file(p, lfd, ops, img);
> +	err = do_dump_gen_file(p, lfd, ops, img);
> +	p->link = link_old;
> +	return err;
>  }
>  
>  static int dump_one_file(struct pid *pid, int fd, int lfd, struct fd_opts *opts,
> -- 
> 2.7.5
>