bpf: Allow CGROUP_SKB eBPF program to access sk_buff

This allows cgroup eBPF program to classify packet based on their
protocol or other detail information. Currently program need
CAP_NET_ADMIN privilege to attach a cgroup eBPF program, and A
process with CAP_NET_ADMIN can already see all packets on the system,
for example, by creating an iptables rules that causes the packet to
be passed to userspace via NFLOG.

Signed-off-by: Chenbo Feng <fengc@google.com>
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 14ccb0759fa4daa57217fb334f43216feacd3f7b..8acae64df255d1b2a33fa5b60d95b916bc6e9472 100644 (file)
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2426,6 +2426,7 @@ static bool may_access_skb(enum bpf_prog_type type)
        case BPF_PROG_TYPE_SOCKET_FILTER:
        case BPF_PROG_TYPE_SCHED_CLS:
        case BPF_PROG_TYPE_SCHED_ACT:
+       case BPF_PROG_TYPE_CGROUP_SKB:
                return true;
        default:
                return false;