neigh: some entries can be skipped during dumping

neightbl_dump_info and neigh_dump_table  can skip entries if the
*fill*info functions return an error. This results in an incomplete
dump ((invoked by netlink requests for RTM_GETNEIGHTBL or
RTM_GETNEIGH)

nidx and idx should not be incremented if the current entry was not
placed in the output buffer

Signed-off-by: Gautam Kachroo <gk@aristanetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 6 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index f66c58df8953..278a142d1047 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -1994,8 +1994,8 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
                         if (!net_eq(neigh_parms_net(p), net))
                                 continue;
 
-                        if (nidx++ < neigh_skip)
-                                continue;
+                        if (nidx < neigh_skip)
+                                goto next;
 
                         if (neightbl_fill_param_info(skb, tbl, p,
                                                      NETLINK_CB(cb->skb).pid,
@@ -2003,6 +2003,8 @@ static int neightbl_dump_info(struct sk_buff *skb, struct netlink_callback *cb)
                                                      RTM_NEWNEIGHTBL,
                                                      NLM_F_MULTI) <= 0)
                                 goto out;
+                next:
+                        nidx++;
                 }
 
                 neigh_skip = 0;
@@ -2082,12 +2084,10 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
                 if (h > s_h)
                         s_idx = 0;
                 for (n = tbl->hash_buckets[h], idx = 0; n; n = n->next) {
-                        int lidx;
                         if (dev_net(n->dev) != net)
                                 continue;
-                        lidx = idx++;
-                        if (lidx < s_idx)
-                                continue;
+                        if (idx < s_idx)
+                                goto next;
                         if (neigh_fill_info(skb, n, NETLINK_CB(cb->skb).pid,
                                             cb->nlh->nlmsg_seq,
                                             RTM_NEWNEIGH,
@@ -2096,6 +2096,8 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
                                 rc = -1;
                                 goto out;
                         }
+                next:
+                        idx++;
                 }
         }
         read_unlock_bh(&tbl->lock);