[PATCH net v2] net/ipv6: don't return positive numbers when nothing was dumped

[PATCH net v2] net/ipv6: don't return positive numbers when nothing was dumped

[Jakub Kicinski]

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@netronome.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 net/ipv6/addrconf.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 57198b3c86da..015e5ccbe306 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5155,6 +5155,8 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
 			if (idev) {
 				err = in6_dump_addrs(idev, skb, cb, s_ip_idx,
 						     &fillargs);
+				if (err > 0)
+					err = 0;
 			}
 			goto put_tgt_net;
 		}
-- 
2.19.2

Re: [PATCH net v2] net/ipv6: don't return positive numbers when nothing was dumped

[David Ahern]

On 1/22/19 3:47 PM, Jakub Kicinski wrote:
> 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@netronome.com>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> ---
>  net/ipv6/addrconf.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 57198b3c86da..015e5ccbe306 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -5155,6 +5155,8 @@ static int inet6_dump_addr(struct sk_buff *skb, struct netlink_callback *cb,
>  			if (idev) {
>  				err = in6_dump_addrs(idev, skb, cb, s_ip_idx,
>  						     &fillargs);
> +				if (err > 0)
> +					err = 0;
>  			}
>  			goto put_tgt_net;
>  		}
> 

Reviewed-by: David Ahern <dsahern@gmail.com>
Tested-by: David Ahern <dsahern@gmail.com>

Thanks, Jakub.

Re: [PATCH net v2] net/ipv6: don't return positive numbers when nothing was dumped

[David Miller]

From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Tue, 22 Jan 2019 14:47:19 -0800

> 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@netronome.com>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

Applied, and since the RTM_GETADDR regression fix was backports I'll have
to -stable this as well.

Thanks!