[PATCH net 4/4] net: rtnl_dump_all needs to propagate error from dumpit function

[David Ahern]

From: David Ahern <dsah...@gmail.com>

If an address, route or netconf dump request is sent for AF_UNSPEC, then
rtnl_dump_all is used to do the dump across all address families. If one
of the dumpit functions fails (e.g., invalid attributes in the dump
request) then rtnl_dump_all needs to propagate that error so the user
gets an appropriate response instead of just getting no data.

Fixes: effe67926624 ("net: Enable kernel side filtering of route dumps")
Fixes: 5fcd266a9f64 ("net/ipv4: Add support for dumping addresses for a 
specific device")
Fixes: 6371a71f3a3b ("net/ipv6: Add support for dumping addresses for a 
specific device")
Signed-off-by: David Ahern <dsah...@gmail.com>
---
 net/core/rtnetlink.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 0958c7be2c22..f679c7a7d761 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -3333,6 +3333,7 @@ static int rtnl_dump_all(struct sk_buff *skb, struct 
netlink_callback *cb)
        int idx;
        int s_idx = cb->family;
        int type = cb->nlh->nlmsg_type - RTM_BASE;
+       int ret = 0;
 
        if (s_idx == 0)
                s_idx = 1;
@@ -3365,12 +3366,13 @@ static int rtnl_dump_all(struct sk_buff *skb, struct 
netlink_callback *cb)
                        cb->prev_seq = 0;
                        cb->seq = 0;
                }
-               if (dumpit(skb, cb))
+               ret = dumpit(skb, cb);
+               if (ret < 0)
                        break;
        }
        cb->family = idx;
 
-       return skb->len;
+       return skb->len ? : ret;
 }
 
 struct sk_buff *rtmsg_ifinfo_build_skb(int type, struct net_device *dev,
-- 
2.11.0