netlink: fixup regression in RTM_GETADDR

This commit fixes a regression in AF_INET/RTM_GETADDR and
AF_INET6/RTM_GETADDR.

Before this commit, the kernel would stop dumping addresses once the first
skb was full and end the stream with NLMSG_DONE(-EMSGSIZE). The error
shouldn't be sent back to netlink_dump so the callback is kept alive. The
userspace is expected to call back with a new empty skb.

Changes from V1:
 - The error is not handled in netlink_dump anymore but rather in
   inet_dump_ifaddr and inet6_dump_addr directly as suggested by
   David Ahern.

Fixes: d7e38611b81e ("net/ipv4: Put target net when address dump fails due to bad attributes")
Fixes: 242afaa6968c ("net/ipv6: Put target net when address dump fails due to bad attributes")

Cc: David Ahern <dsahern@gmail.com>
Cc: "David S . Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: Arthur Gautier <baloo@gandi.net>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 04ba321..e258a00 100644 (file)
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1826,7 +1826,7 @@ put_tgt_net:
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);
 
-       return err < 0 ? err : skb->len;
+       return skb->len ? : err;
 }
 
 static void rtmsg_ifa(int event, struct in_ifaddr *ifa, struct nlmsghdr *nlh,

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 8eeec6e..93d5ad2 100644 (file)
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5154,7 +5154,7 @@ put_tgt_net:
        if (fillargs.netnsid >= 0)
                put_net(tgt_net);
 
-       return err < 0 ? err : skb->len;
+       return skb->len ? : err;
 }
 
 static int inet6_dump_ifaddr(struct sk_buff *skb, struct netlink_callback *cb)