From d5563d367c2ce48ea3d675c77f7109f37311943d Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Wed, 24 Oct 2018 22:05:46 +0200 Subject: [PATCH] bpf: fix cg_skb types to hint access type in may_access_direct_pkt_data Commit b39b5f411dcf ("bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB") added direct packet access for skbs in cg_skb program types, however allowed access type was not added to the may_access_direct_pkt_data() helper. Therefore the latter always returns false. This is not directly an issue, it just means writes are unconditionally disabled (which is correct) but also reads. Latter is relevant in this function when BPF helpers may read direct packet data which is unconditionally disabled then. Fix it by properly adding BPF_PROG_TYPE_CGROUP_SKB to may_access_direct_pkt_data(). Fixes: b39b5f411dcf ("bpf: add cg_skb_is_valid_access for BPF_PROG_TYPE_CGROUP_SKB") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Cc: Song Liu Signed-off-by: Alexei Starovoitov --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index b0cc8f2ff95f..5fc9a658af0e 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1393,6 +1393,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env, case BPF_PROG_TYPE_LWT_SEG6LOCAL: case BPF_PROG_TYPE_SK_REUSEPORT: case BPF_PROG_TYPE_FLOW_DISSECTOR: + case BPF_PROG_TYPE_CGROUP_SKB: if (t == BPF_WRITE) return false; /* fallthrough */ -- 2.30.2