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From:   Roman Gushchin <guro@fb.com>
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        <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH bpf-next 07/14] bpf: don't allow create maps of cgroup local storages
Date:   Thu, 28 Jun 2018 09:47:12 -0700
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As there is one-to-one relation between a bpf program
and cgroup local storage map, there is no sense in
creating a map of cgroup local storage maps.

Forbid it explicitly to avoid possible side effects.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
 kernel/bpf/map_in_map.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/map_in_map.c b/kernel/bpf/map_in_map.c
index 1da574612bea..3bfbf4464416 100644
--- a/kernel/bpf/map_in_map.c
+++ b/kernel/bpf/map_in_map.c
@@ -23,7 +23,8 @@ struct bpf_map *bpf_map_meta_alloc(int inner_map_ufd)
 	 * is a runtime binding.  Doing static check alone
 	 * in the verifier is not enough.
 	 */
-	if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY) {
+	if (inner_map->map_type == BPF_MAP_TYPE_PROG_ARRAY ||
+	    inner_map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE) {
 		fdput(f);
 		return ERR_PTR(-ENOTSUPP);
 	}
-- 
2.14.4