IB/core: Only maintain real QPs in the security lists

When modify QP is called on a shared QP update the security context for
the real QP. When security is subsequently enforced the shared QP
handles will be checked as well.

Without this change shared QP handles get added to the port/pkey lists,
which is a bug, because not all shared QP handles will be checked for
access. Also the shared QP security context wouldn't get removed from
the port/pkey lists causing access to free memory and list corruption
when they are destroyed.

Cc: stable@vger.kernel.org
Fixes: d291f1a65232 ("IB/core: Enforce PKey security on QPs")
Signed-off-by: Daniel Jurgens <danielj@mellanox.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/core/security.c

@@ -87,16 +87,14 @@ static int enforce_qp_pkey_security(u16 pkey,
 	if (ret)
 		return ret;
 
-	if (qp_sec->qp == qp_sec->qp->real_qp) {
-		list_for_each_entry(shared_qp_sec,
-				    &qp_sec->shared_qp_list,
-				    shared_qp_list) {
-			ret = security_ib_pkey_access(shared_qp_sec->security,
-						      subnet_prefix,
-						      pkey);
-			if (ret)
-				return ret;
-		}
+	list_for_each_entry(shared_qp_sec,
+			    &qp_sec->shared_qp_list,
+			    shared_qp_list) {
+		ret = security_ib_pkey_access(shared_qp_sec->security,
+					      subnet_prefix,
+					      pkey);
+		if (ret)
+			return ret;
 	}
 	return 0;
 }
@@ -560,15 +558,22 @@ int ib_security_modify_qp(struct ib_qp *qp,
 	int ret = 0;
 	struct ib_ports_pkeys *tmp_pps;
 	struct ib_ports_pkeys *new_pps;
-	bool special_qp = (qp->qp_type == IB_QPT_SMI ||
-			   qp->qp_type == IB_QPT_GSI ||
-			   qp->qp_type >= IB_QPT_RESERVED1);
+	struct ib_qp *real_qp = qp->real_qp;
+	bool special_qp = (real_qp->qp_type == IB_QPT_SMI ||
+			   real_qp->qp_type == IB_QPT_GSI ||
+			   real_qp->qp_type >= IB_QPT_RESERVED1);
 	bool pps_change = ((qp_attr_mask & (IB_QP_PKEY_INDEX | IB_QP_PORT)) ||
 			   (qp_attr_mask & IB_QP_ALT_PATH));
 
+	/* The port/pkey settings are maintained only for the real QP. Open
+	 * handles on the real QP will be in the shared_qp_list. When
+	 * enforcing security on the real QP all the shared QPs will be
+	 * checked as well.
+	 */
+
 	if (pps_change && !special_qp) {
-		mutex_lock(&qp->qp_sec->mutex);
-		new_pps = get_new_pps(qp,
+		mutex_lock(&real_qp->qp_sec->mutex);
+		new_pps = get_new_pps(real_qp,
 				      qp_attr,
 				      qp_attr_mask);
 
@@ -586,14 +591,14 @@ int ib_security_modify_qp(struct ib_qp *qp,
 
 		if (!ret)
 			ret = check_qp_port_pkey_settings(new_pps,
-							  qp->qp_sec);
+							  real_qp->qp_sec);
 	}
 
 	if (!ret)
-		ret = qp->device->modify_qp(qp->real_qp,
-					    qp_attr,
-					    qp_attr_mask,
-					    udata);
+		ret = real_qp->device->modify_qp(real_qp,
+						 qp_attr,
+						 qp_attr_mask,
+						 udata);
 
 	if (pps_change && !special_qp) {
 		/* Clean up the lists and free the appropriate
@@ -602,8 +607,8 @@ int ib_security_modify_qp(struct ib_qp *qp,
 		if (ret) {
 			tmp_pps = new_pps;
 		} else {
-			tmp_pps = qp->qp_sec->ports_pkeys;
-			qp->qp_sec->ports_pkeys = new_pps;
+			tmp_pps = real_qp->qp_sec->ports_pkeys;
+			real_qp->qp_sec->ports_pkeys = new_pps;
 		}
 
 		if (tmp_pps) {
@@ -611,7 +616,7 @@ int ib_security_modify_qp(struct ib_qp *qp,
 			port_pkey_list_remove(&tmp_pps->alt);
 		}
 		kfree(tmp_pps);
-		mutex_unlock(&qp->qp_sec->mutex);
+		mutex_unlock(&real_qp->qp_sec->mutex);
 	}
 	return ret;
 }