On Wed, 2020-09-30 at 13:01 +0200, Harald Welte wrote:
Hi Richard,
I don't fully understand in which context you need / use those SELinux GTP hooks,
As in the reply to Pablo, I did it for no particular reason other than idle curiosity, and given the attempted move to Open 5G I thought adding MAC support might be useful somewhere along the line.
however one comment from the point of view of somebody who is working on GGSN/P-GW software using the GTP kernel module:
On Wed, Sep 30, 2020 at 10:49:34AM +0100, Richard Haines wrote:
+selinux_gtp_dev_cmd() +~~~~~~~~~~~~~~~~~~~~~ +Validate if the caller (current SID) and the GTP device SID have the required +permission to perform the operation. The GTP/SELinux permission map is +as follow::
- GTP_CMD_NEWPDP = gtp { add }
- GTP_CMD_DELPDP = gtp { del }
- GTP_CMD_GETPDP = gtp { get }
Wouldn't it make sense to differentiate between:
a) add/del/get on the GTP netdev b) add/del/get on the indivudual PDP wihin the GTP netdev
'a' is typically only created once at startup of a GGSN/P-GW software, or is done even at system stat-up time.
'b' is performed frequently during runtime as the GGSN/P-GW function runs, as subscribers attach to / detach from the cellular network.
By differentiating between those two, one could further constrain the permissions required at runtime.
Yes, at first I did separate them (add_dev, del_dev, add_pkt, del_pkt, get_pkt), so if this patchset goes anywhere then I can change it no problem. I guess the '*_pkt' permissions would cover PDP for 3G and PDR & FAR for 5G ?. I didn't implement 'get_dev' but thought it could be useful for retrieving the security context of a device, but that requires passing it back via netlink so thought I would leave it until later.