[PATCH 3.16.y-ckt 249/254] netfilter: xt_bpf: add mising opaque struct sk_filter definition

[Luis Henriques]

3.16.7-ckt2 -stable review patch.  If anyone has any objections, please let me know.

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

From: Pablo Neira <pablo at netfilter.org>

commit e10038a8ec06ac819b7552bb67aaa6d2d6f850c1 upstream.

This structure is not exposed to userspace, so fix this by defining
struct sk_filter; so we skip the casting in kernelspace. This is safe
since userspace has no way to lurk with that internal pointer.

Fixes: e6f30c7 ("netfilter: x_tables: add xt_bpf match")
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>
Acked-by: Willem de Bruijn <willemb at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 include/uapi/linux/netfilter/xt_bpf.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/uapi/linux/netfilter/xt_bpf.h b/include/uapi/linux/netfilter/xt_bpf.h
index 5dda450eb55b..2ec9fbcd06f9 100644
--- a/include/uapi/linux/netfilter/xt_bpf.h
+++ b/include/uapi/linux/netfilter/xt_bpf.h
@@ -6,6 +6,8 @@
 
 #define XT_BPF_MAX_NUM_INSTR	64
 
+struct sk_filter;
+
 struct xt_bpf_info {
 	__u16 bpf_program_num_elem;
 	struct sock_filter bpf_program[XT_BPF_MAX_NUM_INSTR];
-- 
2.1.0