IB/core: For multicast functions, verify that LIDs are multicast LIDs

The Infiniband spec defines "A multicast address is defined by a
MGID and a MLID" (section 10.5).  Currently the MLID value is not
validated.

Add check to verify that the MLID value is in the correct address
range.

Fixes: 0c33aee ("[IB] Add checks to multicast attach and detach")
Cc: [email protected]
Reviewed-by: Ira Weiny <[email protected]>
Reviewed-by: Dasaratharaman Chandramouli <[email protected]>
Signed-off-by: Michael J. Ruhl <[email protected]>
Signed-off-by: Dennis Dalessandro <[email protected]>
Reviewed-by: Leon Romanovsky <[email protected]>
Signed-off-by: Doug Ledford <[email protected]>
(cherry picked from commit 8561eae)

The reason for applying this patch is a bug in ibacm, which goes
undetected without this patch. For further information, see
https://patchwork.kernel.org/patch/10008461/

Signed-off-by: Brian Maly <[email protected]>

Conflicts:

   * Had to add the define IB_MULTICAST_LID_BASE in
     include/rdma/ib_verbs.h, due to missing commit b4e6439
     ("IB/rdmavt: Break rdma_vt main include header file up").

Orabug: 28700490

Signed-off-by: Håkon Bugge <[email protected]>
Reviewed-by: Shannon Nelson <[email protected]>

---
v2 -> v3:
   * Added Shannon's r-b

v1 -> v2:
   * Adding IB_MULTICAST_LID_BASE to ib_verbs.h
   * A little more verbose commit message

Signed-off-by: Brian Maly <[email protected]>

Author: mjruhl

drivers/infiniband/core/verbs.c

@@ -1417,7 +1417,9 @@ int ib_attach_mcast(struct ib_qp *qp, union ib_gid *gid, u16 lid)
 
 	if (!qp->device->attach_mcast)
 		return -ENOSYS;
-	if (gid->raw[0] != 0xff || qp->qp_type != IB_QPT_UD)
+	if (gid->raw[0] != 0xff || qp->qp_type != IB_QPT_UD ||
+	    lid < be16_to_cpu(IB_MULTICAST_LID_BASE) ||
+	    lid == be16_to_cpu(IB_LID_PERMISSIVE))
 		return -EINVAL;
 
 	ret = qp->device->attach_mcast(qp, gid, lid);
@@ -1433,7 +1435,9 @@ int ib_detach_mcast(struct ib_qp *qp, union ib_gid *gid, u16 lid)
 
 	if (!qp->device->detach_mcast)
 		return -ENOSYS;
-	if (gid->raw[0] != 0xff || qp->qp_type != IB_QPT_UD)
+	if (gid->raw[0] != 0xff || qp->qp_type != IB_QPT_UD ||
+	    lid < be16_to_cpu(IB_MULTICAST_LID_BASE) ||
+	    lid == be16_to_cpu(IB_LID_PERMISSIVE))
 		return -EINVAL;
 
 	ret = qp->device->detach_mcast(qp, gid, lid);

include/rdma/ib_verbs.h

@@ -469,6 +469,7 @@ enum {
 };
 
 #define IB_LID_PERMISSIVE	cpu_to_be16(0xFFFF)
+#define IB_MULTICAST_LID_BASE	cpu_to_be16(0xC000)
 
 enum ib_ah_flags {
 	IB_AH_GRH	= 1