Re: [PATCH 4/4] ib_srpt: Convert acl lookup to modern get_initiator_node_acl usage

From: Bart Van Assche
Date: Fri Jan 08 2016 - 04:35:54 EST

On 01/08/2016 10:17 AM, Nicholas A. Bellinger wrote:
On Fri, 2016-01-08 at 09:52 +0100, Bart Van Assche wrote:
On 01/08/2016 08:15 AM, Nicholas A. Bellinger wrote:
@@ -2574,24 +2558,18 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,

pr_debug("registering session %s\n", ch->sess_name);

- nacl = srpt_lookup_acl(sport, ch->i_port_id);
- if (!nacl) {
+ se_acl = core_tpg_get_initiator_node_acl(&sport->port_tpg_1, ch->sess_name);
+ if (!se_acl) {
pr_info("Rejected login because no ACL has been"
" configured yet for initiator %s.\n", ch->sess_name);
rej->reason = cpu_to_be32(
+ transport_free_session(ch->sess);
goto destroy_ib;
+ ch->sess->se_node_acl = se_acl;

This is a backwards-incompatible change. Today the ib_srpt target driver
accepts initiator port names with and without leading "0x". With this
change the "0x" prefix becomes mandatory.

The internally ib_srpt formatted ch->sess_name already needs to match
se_node_acl->initiatorname for se_node_acl->acl_group configfs group
shutdown reference..

How does this patch become a backworks-incompatible change for that..?

Hello Nic,

Personally I'm not that worried about this change but I wanted to report it anyway. The current algorithm is as follows:
- When a directory is created in configfs for an initiator, the
initiator name is parsed and stored in binary form in struct
srpt_node_acl. The parsing function accepts both initiator
names that start with a "0x" prefix and initiator names that
do not have that prefix.
- During login the initiator port ID provided by the initiator in
the SRP login request is compared with the binary initiator port ID
in struct srpt_node_acl.

The patch at the start of this e-mail thread changes this behavior because core_tpg_get_initiator_node_acl() looks up the initiator port ID in a list that contains the ASCII representations of the initiator port ID. This means that the initiator port name will only be found by core_tpg_get_initiator_node_acl() if the name format used in the mkdir command matches the initiator name format used by the core_tpg_get_initiator_node_acl() caller, this means with "0x" prefix.