net: Fix ns_capable check in sock_diag_put_filterinfo

The caller needs capabilities on the namespace being queried, not on
their own namespace.  This is a security bug, although it likely has
only a minor impact.

Cc: stable@vger.kernel.org
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Acked-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 3 insertions, 3 deletions

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index d7af18859322..9deb6abd6cf6 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -49,7 +49,7 @@ int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
 }
 EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);
 
-int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
+int sock_diag_put_filterinfo(struct sock *sk,
                              struct sk_buff *skb, int attrtype)
 {
         struct sock_fprog_kern *fprog;
@@ -58,7 +58,7 @@ int sock_diag_put_filterinfo(struct user_namespace *user_ns, struct sock *sk,
         unsigned int flen;
         int err = 0;
 
-        if (!ns_capable(user_ns, CAP_NET_ADMIN)) {
+        if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN)) {
                 nla_reserve(skb, attrtype, 0);
                 return 0;
         }
diff --git a/net/packet/diag.c b/net/packet/diag.c
index 533ce4ff108a..435ff99ba8c7 100644
--- a/net/packet/diag.c
+++ b/net/packet/diag.c
@@ -172,7 +172,7 @@ static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
                 goto out_nlmsg_trim;
 
         if ((req->pdiag_show & PACKET_SHOW_FILTER) &&
-            sock_diag_put_filterinfo(user_ns, sk, skb, PACKET_DIAG_FILTER))
+            sock_diag_put_filterinfo(sk, skb, PACKET_DIAG_FILTER))
                 goto out_nlmsg_trim;
 
         return nlmsg_end(skb, nlh);