[Devel] [CRIU] [PATCH] vz7: files -- Don't access value from stack in outer contex

[Andrei Vagin]

Do we need it for the upstream criu? Could you send a patch for it?

On Wed, Jul 12, 2017 at 05:41:38PM +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 91dfcef..420a83f 100644
> --- a/criu/files.c
> +++ b/criu/files.c
> @@ -410,8 +410,11 @@ 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:
> @@ -426,8 +429,6 @@ 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;
> @@ -436,11 +437,15 @@ 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 check_blkdev(struct fd_parms *p, int lfd)
> -- 
> 2.7.5
> 
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