[PATCH 4.20 08/80] net/ipv6: dont return positive numbers when nothing was dumped

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>

[ Upstream commit 1518039f6b5ac794313c24c76f85cead0cd60f6c ]

in6_dump_addrs() returns a positive 1 if there was nothing to dump.
This return value can not be passed as return from inet6_dump_addr()
as is, because it will confuse rtnetlink, resulting in NLMSG_DONE
never getting set:

$ ip addr list dev lo
EOF on netlink
Dump terminated

v2: flip condition to avoid a new goto (DaveA)

Fixes: 7c1e8a3817c5 ("netlink: fixup regression in RTM_GETADDR")
Reported-by: Brendan Galloway <brendan.galloway@xxxxxxxxxxxxx>
Signed-off-by: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxx>
Tested-by: David Ahern <dsahern@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/ipv6/addrconf.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5120,6 +5120,8 @@ static int inet6_dump_addr(struct sk_buf
 			if (idev) {
 				err = in6_dump_addrs(idev, skb, cb, s_ip_idx,
 						     &fillargs);
+				if (err > 0)
+					err = 0;
 			}
 			goto put_tgt_net;
 		}