IB/core: Enforce PKey security on QPs

Add new LSM hooks to allocate and free security contexts and check for
permission to access a PKey.

Allocate and free a security context when creating and destroying a QP.
This context is used for controlling access to PKeys.

When a request is made to modify a QP that changes the port, PKey index,
or alternate path, check that the QP has permission for the PKey in the
PKey table index on the subnet prefix of the port. If the QP is shared
make sure all handles to the QP also have access.

Store which port and PKey index a QP is using. After the reset to init
transition the user can modify the port, PKey index and alternate path
independently. So port and PKey settings changes can be a merge of the
previous settings and the new ones.

In order to maintain access control if there are PKey table or subnet
prefix change keep a list of all QPs are using each PKey index on
each port. If a change occurs all QPs using that device and port must
have access enforced for the new cache settings.

These changes add a transaction to the QP modify process. Association
with the old port and PKey index must be maintained if the modify fails,
and must be removed if it succeeds. Association with the new port and
PKey index must be established prior to the modify and removed if the
modify fails.

1. When a QP is modified to a particular Port, PKey index or alternate
   path insert that QP into the appropriate lists.

2. Check permission to access the new settings.

3. If step 2 grants access attempt to modify the QP.

4a. If steps 2 and 3 succeed remove any prior associations.

4b. If ether fails remove the new setting associations.

If a PKey table or subnet prefix changes walk the list of QPs and
check that they have permission. If not send the QP to the error state
and raise a fatal error event. If it's a shared QP make sure all the
QPs that share the real_qp have permission as well. If the QP that
owns a security structure is denied access the security structure is
marked as such and the QP is added to an error_list. Once the moving
the QP to error is complete the security structure mark is cleared.

Maintaining the lists correctly turns QP destroy into a transaction.
The hardware driver for the device frees the ib_qp structure, so while
the destroy is in progress the ib_qp pointer in the ib_qp_security
struct is undefined. When the destroy process begins the ib_qp_security
structure is marked as destroying. This prevents any action from being
taken on the QP pointer. After the QP is destroyed successfully it
could still listed on an error_list wait for it to be processed by that
flow before cleaning up the structure.

If the destroy fails the QPs port and PKey settings are reinserted into
the appropriate lists, the destroying flag is cleared, and access control
is enforced, in case there were any cache changes during the destroy
flow.

To keep the security changes isolated a new file is used to hold security
related functionality.

Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Acked-by: Doug Ledford <dledford@redhat.com>
[PM: merge fixup in ib_verbs.h and uverbs_cmd.c]
Signed-off-by: Paul Moore <paul@paul-moore.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 080f34e66017..6d9f41fffda7 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -8,6 +8,7 @@
  * Copyright (C) 2001 Silicon Graphics, Inc. (Trust Technology Group)
  * Copyright (C) 2015 Intel Corporation.
  * Copyright (C) 2015 Casey Schaufler <casey@schaufler-ca.com>
+ * Copyright (C) 2016 Mellanox Techonologies
  *
  *	This program is free software; you can redistribute it and/or modify
  *	it under the terms of the GNU General Public License as published by
@@ -911,6 +912,21 @@
  *	associated with the TUN device's security structure.
  *	@security pointer to the TUN devices's security structure.
  *
+ * Security hooks for Infiniband
+ *
+ * @ib_pkey_access:
+ *	Check permission to access a pkey when modifing a QP.
+ *	@subnet_prefix the subnet prefix of the port being used.
+ *	@pkey the pkey to be accessed.
+ *	@sec pointer to a security structure.
+ * @ib_alloc_security:
+ *	Allocate a security structure for Infiniband objects.
+ *	@sec pointer to a security structure pointer.
+ *	Returns 0 on success, non-zero on failure
+ * @ib_free_security:
+ *	Deallocate an Infiniband security structure.
+ *	@sec contains the security structure to be freed.
+ *
  * Security hooks for XFRM operations.
  *
  * @xfrm_policy_alloc_security:
@@ -1620,6 +1636,12 @@ union security_list_options {
 	int (*tun_dev_open)(void *security);
 #endif	/* CONFIG_SECURITY_NETWORK */
 
+#ifdef CONFIG_SECURITY_INFINIBAND
+	int (*ib_pkey_access)(void *sec, u64 subnet_prefix, u16 pkey);
+	int (*ib_alloc_security)(void **sec);
+	void (*ib_free_security)(void *sec);
+#endif	/* CONFIG_SECURITY_INFINIBAND */
+
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 	int (*xfrm_policy_alloc_security)(struct xfrm_sec_ctx **ctxp,
 					  struct xfrm_user_sec_ctx *sec_ctx,
@@ -1851,6 +1873,11 @@ struct security_hook_heads {
 	struct list_head tun_dev_attach;
 	struct list_head tun_dev_open;
 #endif	/* CONFIG_SECURITY_NETWORK */
+#ifdef CONFIG_SECURITY_INFINIBAND
+	struct list_head ib_pkey_access;
+	struct list_head ib_alloc_security;
+	struct list_head ib_free_security;
+#endif	/* CONFIG_SECURITY_INFINIBAND */
 #ifdef CONFIG_SECURITY_NETWORK_XFRM
 	struct list_head xfrm_policy_alloc_security;
 	struct list_head xfrm_policy_clone_security;