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, 48 insertions, 0 deletions

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9dc4e7e..0e480a5 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1614,6 +1614,45 @@ struct ib_rwq_ind_table_init_attr {
 	struct ib_wq	**ind_tbl;
 };
 
+enum port_pkey_state {
+	IB_PORT_PKEY_NOT_VALID = 0,
+	IB_PORT_PKEY_VALID = 1,
+	IB_PORT_PKEY_LISTED = 2,
+};
+
+struct ib_qp_security;
+
+struct ib_port_pkey {
+	enum port_pkey_state	state;
+	u16			pkey_index;
+	u8			port_num;
+	struct list_head	qp_list;
+	struct list_head	to_error_list;
+	struct ib_qp_security  *sec;
+};
+
+struct ib_ports_pkeys {
+	struct ib_port_pkey	main;
+	struct ib_port_pkey	alt;
+};
+
+struct ib_qp_security {
+	struct ib_qp	       *qp;
+	struct ib_device       *dev;
+	/* Hold this mutex when changing port and pkey settings. */
+	struct mutex		mutex;
+	struct ib_ports_pkeys  *ports_pkeys;
+	/* A list of all open shared QP handles.  Required to enforce security
+	 * properly for all users of a shared QP.
+	 */
+	struct list_head        shared_qp_list;
+	void                   *security;
+	bool			destroying;
+	atomic_t		error_list_count;
+	struct completion	error_complete;
+	int			error_comps_pending;
+};
+
 /*
  * @max_write_sge: Maximum SGE elements per RDMA WRITE request.
  * @max_read_sge:  Maximum SGE elements per RDMA READ request.
@@ -1643,6 +1682,7 @@ struct ib_qp {
 	u32			max_read_sge;
 	enum ib_qp_type		qp_type;
 	struct ib_rwq_ind_table *rwq_ind_tbl;
+	struct ib_qp_security  *qp_sec;
 };
 
 struct ib_mr {
@@ -1941,6 +1981,12 @@ struct rdma_netdev {
 			    union ib_gid *gid, u16 mlid);
 };
 
+struct ib_port_pkey_list {
+	/* Lock to hold while modifying the list. */
+	spinlock_t                    list_lock;
+	struct list_head              pkey_list;
+};
+
 struct ib_device {
 	/* Do not access @dma_device directly from ULP nor from HW drivers. */
 	struct device                *dma_device;
@@ -1964,6 +2010,8 @@ struct ib_device {
 
 	int			      num_comp_vectors;
 
+	struct ib_port_pkey_list     *port_pkey_list;
+
 	struct iw_cm_verbs	     *iwcm;
 
 	/**