bpf: add tests for direct packet access from CGROUP_SKB
Tests are added to make sure CGROUP_SKB cannot access: tc_classid, data_meta, flow_keys and can read and write: mark, prority, and cb[0-4] and can read other fields. To make selftest with skb->sk work, a dummy sk is added in bpf_prog_test_run_skb(). Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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b39b5f411d
commit
2cb494a36c
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@ -10,6 +10,8 @@
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#include <linux/etherdevice.h>
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#include <linux/filter.h>
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#include <linux/sched/signal.h>
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#include <net/sock.h>
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#include <net/tcp.h>
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static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx,
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struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE])
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@ -115,6 +117,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
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u32 retval, duration;
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int hh_len = ETH_HLEN;
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struct sk_buff *skb;
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struct sock *sk;
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void *data;
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int ret;
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@ -137,11 +140,21 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
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break;
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}
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skb = build_skb(data, 0);
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if (!skb) {
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sk = kzalloc(sizeof(struct sock), GFP_USER);
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if (!sk) {
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kfree(data);
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return -ENOMEM;
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}
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sock_net_set(sk, current->nsproxy->net_ns);
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sock_init_data(NULL, sk);
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skb = build_skb(data, 0);
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if (!skb) {
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kfree(data);
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kfree(sk);
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return -ENOMEM;
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}
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skb->sk = sk;
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skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
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__skb_put(skb, size);
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@ -159,6 +172,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
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if (pskb_expand_head(skb, nhead, 0, GFP_USER)) {
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kfree_skb(skb);
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kfree(sk);
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return -ENOMEM;
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}
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}
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@ -171,6 +185,7 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
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size = skb_headlen(skb);
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ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
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kfree_skb(skb);
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kfree(sk);
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return ret;
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}
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@ -4862,6 +4862,177 @@ static struct bpf_test tests[] = {
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.result = REJECT,
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.flags = F_NEEDS_EFFICIENT_UNALIGNED_ACCESS,
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},
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{
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"direct packet read test#1 for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
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offsetof(struct __sk_buff, data)),
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BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
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offsetof(struct __sk_buff, data_end)),
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BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
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offsetof(struct __sk_buff, len)),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, pkt_type)),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, mark)),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
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offsetof(struct __sk_buff, mark)),
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BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
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offsetof(struct __sk_buff, queue_mapping)),
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BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
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offsetof(struct __sk_buff, protocol)),
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BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_1,
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offsetof(struct __sk_buff, vlan_present)),
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BPF_MOV64_REG(BPF_REG_0, BPF_REG_2),
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BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
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BPF_JMP_REG(BPF_JGT, BPF_REG_0, BPF_REG_3, 1),
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BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_2, 0),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"direct packet read test#2 for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
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offsetof(struct __sk_buff, vlan_tci)),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, vlan_proto)),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, priority)),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
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offsetof(struct __sk_buff, priority)),
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BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
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offsetof(struct __sk_buff,
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ingress_ifindex)),
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BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
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offsetof(struct __sk_buff, tc_index)),
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BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_1,
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offsetof(struct __sk_buff, hash)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"direct packet read test#3 for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
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offsetof(struct __sk_buff, cb[0])),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, cb[1])),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, cb[2])),
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BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
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offsetof(struct __sk_buff, cb[3])),
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BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
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offsetof(struct __sk_buff, cb[4])),
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BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_1,
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offsetof(struct __sk_buff, napi_id)),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_4,
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offsetof(struct __sk_buff, cb[0])),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_5,
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offsetof(struct __sk_buff, cb[1])),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_6,
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offsetof(struct __sk_buff, cb[2])),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_7,
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offsetof(struct __sk_buff, cb[3])),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_8,
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offsetof(struct __sk_buff, cb[4])),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"direct packet read test#4 for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1,
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offsetof(struct __sk_buff, family)),
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BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
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offsetof(struct __sk_buff, remote_ip4)),
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BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1,
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offsetof(struct __sk_buff, local_ip4)),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, remote_ip6[0])),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, remote_ip6[1])),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, remote_ip6[2])),
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BPF_LDX_MEM(BPF_W, BPF_REG_5, BPF_REG_1,
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offsetof(struct __sk_buff, remote_ip6[3])),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, local_ip6[0])),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, local_ip6[1])),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, local_ip6[2])),
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BPF_LDX_MEM(BPF_W, BPF_REG_6, BPF_REG_1,
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offsetof(struct __sk_buff, local_ip6[3])),
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BPF_LDX_MEM(BPF_W, BPF_REG_7, BPF_REG_1,
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offsetof(struct __sk_buff, remote_port)),
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BPF_LDX_MEM(BPF_W, BPF_REG_8, BPF_REG_1,
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offsetof(struct __sk_buff, local_port)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = ACCEPT,
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"invalid access of tc_classid for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
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offsetof(struct __sk_buff, tc_classid)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = REJECT,
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.errstr = "invalid bpf_context access",
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"invalid access of data_meta for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
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offsetof(struct __sk_buff, data_meta)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = REJECT,
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.errstr = "invalid bpf_context access",
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"invalid access of flow_keys for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
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offsetof(struct __sk_buff, flow_keys)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = REJECT,
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.errstr = "invalid bpf_context access",
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"invalid write access to napi_id for CGROUP_SKB",
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.insns = {
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BPF_LDX_MEM(BPF_W, BPF_REG_9, BPF_REG_1,
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offsetof(struct __sk_buff, napi_id)),
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BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_9,
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offsetof(struct __sk_buff, napi_id)),
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BPF_MOV64_IMM(BPF_REG_0, 0),
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BPF_EXIT_INSN(),
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},
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.result = REJECT,
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.errstr = "invalid bpf_context access",
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.prog_type = BPF_PROG_TYPE_CGROUP_SKB,
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},
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{
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"valid cgroup storage access",
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.insns = {
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