[Devel] [PATCH v2 5/8] add user mismatch test

[Kir Kolyshkin]

On 03/22/2013 03:48 AM, Glauber Costa wrote:
> In theory, we won't be able to run if our private area is not owned by
> ourselves.  We could, if it have very wide open security permissions, but we
> should never set up a container like that.
>
> Aside from a basic sanity check, this is intended to catch problems for the few
> people who may have already created containers that will be owned by root:root,
> and will now try to run it unprivileged.
>
> Signed-off-by: Glauber Costa <glommer at parallels.com>
> ---
>   src/lib/env.c | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
>
> diff --git a/src/lib/env.c b/src/lib/env.c
> index 2da848d..ff4dad2 100644
> --- a/src/lib/env.c
> +++ b/src/lib/env.c
> @@ -30,6 +30,7 @@
>   #include <linux/reboot.h>
>   #include <sys/mount.h>
>   #include <sys/utsname.h>
> +#include <sys/stat.h>
>   
>   #include "vzerror.h"
>   #include "res.h"
> @@ -551,6 +552,18 @@ int vps_start_custom(vps_handler *h, envid_t veid, vps_param *param,
>   		logger(-1, 0, "Container is already running");
>   		return VZ_VE_RUNNING;
>   	}
> +	if (!is_vz_kernel(h) && h->can_join_userns) {
> +		struct stat private_stat;
> +		stat(res->fs.private, &private_stat);
> +		if ((private_stat.st_uid != *res->misc.local_uid) ||
> +			(private_stat.st_gid != *res->misc.local_gid)) {
> +			logger(-1, 0, "Container private area is owned by %d:%d"
> +			", but configuration file says we should run with %lu:%lu.\n"
> +			"Refusing to run.", private_stat.st_uid, private_stat.st_gid,
> +			*res->misc.local_uid, *res->misc.local_gid);
> +			return VZ_FS_BAD_TMPL;
> +		}
> +	}
>   	if ((ret = check_ub(h, &res->ub)))
>   		return ret;
>   

looks good (just add checks for local_* being non-NULL)