datapath: Avoid __copy_to/from_user(), __get/put_user() functions.

The advantages of the double-underscore variants of copy_to_user(),
copy_from_user(), get_user(), and put_user() are pretty marginal, at best,
in the places where we are using them, and it's not always obvious that we
are making the right calls to access_ok() beforehand.  So switch to the
safe variants without double underscores.

Suggested-by: Jesse Gross <jesse@nicira.com>

diff --git a/datapath/datapath.c b/datapath/datapath.c
index 475baa4..04b1989 100644 (file)
--- a/datapath/datapath.c
+++ b/datapath/datapath.c
@@ -431,7 +431,7 @@ got_port_no:
        set_internal_devs_mtu(dp);
        dp_sysfs_add_if(dp->ports[port_no]);
 
-       err = __put_user(port_no, &portp->port);
+       err = put_user(port_no, &portp->port);
 
 out_unlock_dp:
        mutex_unlock(&dp->mutex);
@@ -1068,8 +1068,8 @@ static int put_flow(struct datapath *dp, struct odp_flow_put __user *ufp)
        if (error)
                return error;
 
-       if (__copy_to_user(&ufp->flow.stats, &stats,
-                          sizeof(struct odp_flow_stats)))
+       if (copy_to_user(&ufp->flow.stats, &stats,
+                        sizeof(struct odp_flow_stats)))
                return -EFAULT;
 
        return 0;
@@ -1092,15 +1092,15 @@ static int do_answer_query(struct sw_flow *flow, u32 query_flags,
        }
        spin_unlock_irqrestore(&flow->lock, flags);
 
-       if (__copy_to_user(ustats, &stats, sizeof(struct odp_flow_stats)) ||
-           __get_user(n_actions, n_actionsp))
+       if (copy_to_user(ustats, &stats, sizeof(struct odp_flow_stats)) ||
+           get_user(n_actions, n_actionsp))
                return -EFAULT;
 
        if (!n_actions)
                return 0;
 
        sf_acts = rcu_dereference(flow->sf_acts);
-       if (__put_user(sf_acts->n_actions, n_actionsp) ||
+       if (put_user(sf_acts->n_actions, n_actionsp) ||
            (actions && copy_to_user(actions, sf_acts->actions,
                                     sizeof(union odp_action) *
                                     min(sf_acts->n_actions, n_actions))))
@@ -1114,7 +1114,7 @@ static int answer_query(struct sw_flow *flow, u32 query_flags,
 {
        union odp_action *actions;
 
-       if (__get_user(actions, &ufp->actions))
+       if (get_user(actions, &ufp->actions))
                return -EFAULT;
 
        return do_answer_query(flow, query_flags,
@@ -1172,13 +1172,13 @@ static int do_query_flows(struct datapath *dp, const struct odp_flowvec *flowvec
                struct tbl_node *flow_node;
                int error;
 
-               if (__copy_from_user(&uf, ufp, sizeof uf))
+               if (copy_from_user(&uf, ufp, sizeof uf))
                        return -EFAULT;
                memset(uf.key.reserved, 0, sizeof uf.key.reserved);
 
                flow_node = tbl_lookup(table, &uf.key, flow_hash(&uf.key), flow_cmp);
                if (!flow_node)
-                       error = __put_user(ENOENT, &ufp->stats.error);
+                       error = put_user(ENOENT, &ufp->stats.error);
                else
                        error = answer_query(flow_cast(flow_node), uf.flags, ufp);
                if (error)
@@ -1200,7 +1200,7 @@ static int list_flow(struct tbl_node *node, void *cbdata_)
        struct odp_flow __user *ufp = &cbdata->uflows[cbdata->listed_flows++];
        int error;
 
-       if (__copy_to_user(&ufp->key, &flow->key, sizeof flow->key))
+       if (copy_to_user(&ufp->key, &flow->key, sizeof flow->key))
                return -EFAULT;
        error = answer_query(flow, 0, ufp);
        if (error)
@@ -1235,21 +1235,16 @@ static int do_flowvec_ioctl(struct datapath *dp, unsigned long argp,
        int retval;
 
        uflowvec = (struct odp_flowvec __user *)argp;
-       if (!access_ok(VERIFY_WRITE, uflowvec, sizeof *uflowvec) ||
-           copy_from_user(&flowvec, uflowvec, sizeof flowvec))
+       if (copy_from_user(&flowvec, uflowvec, sizeof flowvec))
                return -EFAULT;
 
        if (flowvec.n_flows > INT_MAX / sizeof(struct odp_flow))
                return -EINVAL;
 
-       if (!access_ok(VERIFY_WRITE, flowvec.flows,
-                      flowvec.n_flows * sizeof(struct odp_flow)))
-               return -EFAULT;
-
        retval = function(dp, &flowvec);
        return (retval < 0 ? retval
                : retval == flowvec.n_flows ? 0
-               : __put_user(retval, &uflowvec->n_flows));
+               : put_user(retval, &uflowvec->n_flows));
 }
 
 static int do_execute(struct datapath *dp, const struct odp_execute *execute)