ipv6: Do not assign non-valid address on interface.

Check the type of the address when adding a new one on interface.
- the unspecified address (::) is always disallowed (RFC4291 2.5.2)
- the loopback address is disallowed unless the interface is (one of)
  loopback (RFC4291 2.5.3).
- multicast addresses are disallowed.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 84127d854cfc..8b6875f02039 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -578,6 +578,13 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, int pfxlen,
         struct rt6_info *rt;
         int hash;
         int err = 0;
+        int addr_type = ipv6_addr_type(addr);
+
+        if (addr_type == IPV6_ADDR_ANY ||
+            addr_type & IPV6_ADDR_MULTICAST ||
+            (!(idev->dev->flags & IFF_LOOPBACK) &&
+             addr_type & IPV6_ADDR_LOOPBACK))
+                return ERR_PTR(-EADDRNOTAVAIL);
 
         rcu_read_lock_bh();
         if (idev->dead) {