[lxc-devel] [PATCH 2/1] btrfs: support unprivileged destroy

[Stéphane Graber]

On Tue, May 06, 2014 at 09:43:19PM +0000, Serge Hallyn wrote:
> Do this by calling the bdev->destroy() hook from a user namespace
> configured as the container's.
> 
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Acked-by: Stéphane Graber <stgraber at ubuntu.com>

> ---
>  src/lxc/lxccontainer.c |   50 ++++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 40 insertions(+), 10 deletions(-)
> 
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 9e23c7b..255fde5 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -1987,10 +1987,41 @@ static int lxc_rmdir_onedev_wrapper(void *data)
>  	return lxc_rmdir_onedev(arg);
>  }
>  
> +static int do_bdev_destroy(struct lxc_conf *conf)
> +{
> +	struct bdev *r;
> +	int ret = 0;
> +
> +	r = bdev_init(conf->rootfs.path, conf->rootfs.mount, NULL);
> +	if (!r)
> +		return -1;
> +
> +	if (r->ops->destroy(r) < 0)
> +		ret = -1;
> +	bdev_put(r);
> +	return ret;
> +}
> +
> +static int bdev_destroy_wrapper(void *data)
> +{
> +	struct lxc_conf *conf = data;
> +
> +	if (setgid(0) < 0) {
> +		ERROR("Failed to setgid to 0");
> +		return -1;
> +	}
> +	if (setgroups(0, NULL) < 0)
> +		WARN("Failed to clear groups");
> +	if (setuid(0) < 0) {
> +		ERROR("Failed to setuid to 0");
> +		return -1;
> +	}
> +	return do_bdev_destroy(conf);
> +}
> +
>  // do we want the api to support --force, or leave that to the caller?
>  static bool lxcapi_destroy(struct lxc_container *c)
>  {
> -	struct bdev *r = NULL;
>  	bool bret = false;
>  	int ret;
>  
> @@ -2011,15 +2042,14 @@ static bool lxcapi_destroy(struct lxc_container *c)
>  		goto out;
>  	}
>  
> -	if (!am_unpriv() && c->lxc_conf && c->lxc_conf->rootfs.path && c->lxc_conf->rootfs.mount) {
> -		r = bdev_init(c->lxc_conf->rootfs.path, c->lxc_conf->rootfs.mount, NULL);
> -		if (r) {
> -			if (r->ops->destroy(r) < 0) {
> -				bdev_put(r);
> -				ERROR("Error destroying rootfs for %s", c->name);
> -				goto out;
> -			}
> -			bdev_put(r);
> +	if (c->lxc_conf && c->lxc_conf->rootfs.path && c->lxc_conf->rootfs.mount) {
> +		if (am_unpriv())
> +			ret = userns_exec_1(c->lxc_conf, bdev_destroy_wrapper, c->lxc_conf);
> +		else
> +			ret = do_bdev_destroy(c->lxc_conf);
> +		if (ret < 0) {
> +			ERROR("Error destroying rootfs for %s", c->name);
> +			goto out;
>  		}
>  	}
>  
> -- 
> 1.7.9.5
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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