Re: [PATCH 3/3] libselinux: do not use status page fallback mode internally

[Petr Lautrbach <plautrba@redhat.com>]

Christian Göttsche <cgzones@googlemail.com> writes:

> Currently `avc_init_internal()`, called by `avc_open(3)` and
> `avc_init(3)`, does open the SELinux status page with fallback mode
> enabled.
>
> Quote from man:selinux_status_open(3):
>     In this case, this function tries to open a netlink socket using
>     .BR avc_netlink_open (3) and overwrite corresponding callbacks
>     (setenforce and policyload).  Thus, we need to pay attention to the
>     interaction with these interfaces, when fallback mode is enabled.
>
> Calling `selinux_status_open` internally in fallback mode is bad, cause
> it overrides callbacks from client applications or the internal
> fallback-callbacks get overridden by client applications.
> Note that `avc_open(3)` gets called under the hood by
> `selinux_check_access(3)` without checking for failure.
> Also the status page is available since Linux 2.6.37, so failures of
> `selinux_status_open(3)` in non-fallback mode should only be caused by
> policies not allowing the client process to open/read/map
> the /sys/fs/selinux/status file.

Acked-by: Petr Lautrbach <plautrba@redhat.com>

All 3 are merged now.

Thanks!

> Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
> ---
>  libselinux/src/avc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/libselinux/src/avc.c b/libselinux/src/avc.c
> index 8314d7ba..daaedbc6 100644
> --- a/libselinux/src/avc.c
> +++ b/libselinux/src/avc.c
> @@ -214,7 +214,7 @@ static int avc_init_internal(const char *prefix,
>  		avc_enforcing = rc;
>  	}
>  
> -	rc = selinux_status_open(1);
> +	rc = selinux_status_open(0);
>  	if (rc < 0) {
>  		avc_log(SELINUX_ERROR,
>  			"%s: could not open selinux status page: %d (%s)\n",
> -- 
> 2.31.1