[PATCH net-next v2] netlink: fix compilation after memory mapped patches

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

Depending of the kernel configuration (CONFIG_UIDGID_STRICT_TYPE_CHECKS), we can
get the following errors:

net/netlink/af_netlink.c: In function ‘netlink_queue_mmaped_skb’:
net/netlink/af_netlink.c:663:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kuid_t’
net/netlink/af_netlink.c:664:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kgid_t’
net/netlink/af_netlink.c: In function ‘netlink_ring_set_copied’:
net/netlink/af_netlink.c:693:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kuid_t’
net/netlink/af_netlink.c:694:14: error: incompatible types when assigning to type ‘__u32’ from type ‘kgid_t’

We must use the helpers to get the uid and gid, and also take care of user_ns.

Fix suggested by Eric W. Biederman <ebiederm@xmission.com>.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
---

v2: use from_k{p,g}ui() functions to get the right {p,g}ui

 net/netlink/af_netlink.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index da5601d..d9c7869 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -660,8 +660,8 @@ static void netlink_queue_mmaped_skb(struct sock *sk, struct sk_buff *skb)
 	hdr->nm_len	= skb->len;
 	hdr->nm_group	= NETLINK_CB(skb).dst_group;
 	hdr->nm_pid	= NETLINK_CB(skb).creds.pid;
-	hdr->nm_uid	= NETLINK_CB(skb).creds.uid;
-	hdr->nm_gid	= NETLINK_CB(skb).creds.gid;
+	hdr->nm_uid	= from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
+	hdr->nm_gid	= from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
 	netlink_frame_flush_dcache(hdr);
 	netlink_set_status(hdr, NL_MMAP_STATUS_VALID);
 
@@ -690,8 +690,8 @@ static void netlink_ring_set_copied(struct sock *sk, struct sk_buff *skb)
 	hdr->nm_len	= skb->len;
 	hdr->nm_group	= NETLINK_CB(skb).dst_group;
 	hdr->nm_pid	= NETLINK_CB(skb).creds.pid;
-	hdr->nm_uid	= NETLINK_CB(skb).creds.uid;
-	hdr->nm_gid	= NETLINK_CB(skb).creds.gid;
+	hdr->nm_uid	= from_kuid(sk_user_ns(sk), NETLINK_CB(skb).creds.uid);
+	hdr->nm_gid	= from_kgid(sk_user_ns(sk), NETLINK_CB(skb).creds.gid);
 	netlink_set_status(hdr, NL_MMAP_STATUS_COPY);
 }
 
-- 
1.8.2.1