cgroup: bpf: Add bpf_skb_in_cgroup_proto
Adds a bpf helper, bpf_skb_in_cgroup, to decide if a skb->sk
belongs to a descendant of a cgroup2. It is similar to the
feature added in netfilter:
commit c38c4597e4bf ("netfilter: implement xt_cgroup cgroup2 path match")
The user is expected to populate a BPF_MAP_TYPE_CGROUP_ARRAY
which will be used by the bpf_skb_in_cgroup.
Modifications to the bpf verifier is to ensure BPF_MAP_TYPE_CGROUP_ARRAY
and bpf_skb_in_cgroup() are always used together.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 69ba225..e206c21 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1036,7 +1036,9 @@
goto error;
break;
case BPF_MAP_TYPE_CGROUP_ARRAY:
- goto error;
+ if (func_id != BPF_FUNC_skb_in_cgroup)
+ goto error;
+ break;
default:
break;
}
@@ -1056,6 +1058,10 @@
if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
goto error;
break;
+ case BPF_FUNC_skb_in_cgroup:
+ if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
+ goto error;
+ break;
default:
break;
}
