ipv6: addrconf: fix /proc/net/if_inet6

Commit 1d5783030a1 (ipv6/addrconf: speedup /proc/net/if_inet6 filling)
added bugs hiding some devices from if_inet6 and breaking applications.

"ip -6 addr" could still display all IPv6 addresses, while "ifconfig -a"
couldnt.

One way to reproduce the bug is by starting in a shell :

unshare -n /bin/bash
ifconfig lo up

And in original net namespace, lo device disappeared from if_inet6

Reported-by: Jan Hinnerk Stosch <janhinnerk.stosch@gmail.com>
Tested-by: Jan Hinnerk Stosch <janhinnerk.stosch@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Mihai Maruseac <mihai.maruseac@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index d7c56f8a5b4e76028ebd4f66e5a928ea4ea0887e..0424e4e27414d3bd6c79f5094d0d3907e62b02f5 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3064,14 +3064,15 @@ static struct inet6_ifaddr *if6_get_first(struct seq_file *seq, loff_t pos)
                struct hlist_node *n;
                hlist_for_each_entry_rcu_bh(ifa, n, &inet6_addr_lst[state->bucket],
                                         addr_lst) {
+                       if (!net_eq(dev_net(ifa->idev->dev), net))
+                               continue;
                        /* sync with offset */
                        if (p < state->offset) {
                                p++;
                                continue;
                        }
                        state->offset++;
-                       if (net_eq(dev_net(ifa->idev->dev), net))
-                               return ifa;
+                       return ifa;
                }
 
                /* prepare for next bucket */
@@ -3089,18 +3090,20 @@ static struct inet6_ifaddr *if6_get_next(struct seq_file *seq,
        struct hlist_node *n = &ifa->addr_lst;
 
        hlist_for_each_entry_continue_rcu_bh(ifa, n, addr_lst) {
+               if (!net_eq(dev_net(ifa->idev->dev), net))
+                       continue;
                state->offset++;
-               if (net_eq(dev_net(ifa->idev->dev), net))
-                       return ifa;
+               return ifa;
        }
 
        while (++state->bucket < IN6_ADDR_HSIZE) {
                state->offset = 0;
                hlist_for_each_entry_rcu_bh(ifa, n,
                                     &inet6_addr_lst[state->bucket], addr_lst) {
+                       if (!net_eq(dev_net(ifa->idev->dev), net))
+                               continue;
                        state->offset++;
-                       if (net_eq(dev_net(ifa->idev->dev), net))
-                               return ifa;
+                       return ifa;
                }
        }