selftests/bpf: verify bpf_get_netns_cookie in BPF_PROG_TYPE_CGROUP_SOCKOPT

Add verifier ctx test to call bpf_get_netns_cookie from
cgroup/setsockopt.

  #269/p pass ctx or null check, 1: ctx Did not run the program (not supported) OK
  #270/p pass ctx or null check, 2: null Did not run the program (not supported) OK
  #271/p pass ctx or null check, 3: 1 OK
  #272/p pass ctx or null check, 4: ctx - const OK
  #273/p pass ctx or null check, 5: null (connect) Did not run the program (not supported) OK
  #274/p pass ctx or null check, 6: null (bind) Did not run the program (not supported) OK
  #275/p pass ctx or null check, 7: ctx (bind) Did not run the program (not supported) OK
  #276/p pass ctx or null check, 8: null (bind) OK
  #277/p pass ctx or null check, 9: ctx (cgroup/setsockopt) Did not run the program (not supported) OK
  #278/p pass ctx or null check, 10: null (cgroup/setsockopt) Did not run the program (not supported) OK

Signed-off-by: Stanislav Fomichev <sdf@google.com>

Author: fomichev

tools/testing/selftests/bpf/verifier/ctx.c

@@ -195,3 +195,28 @@
 	.result = REJECT,
 	.errstr = "R1 type=inv expected=ctx",
 },
+{
+	"pass ctx or null check, 9: ctx (cgroup/setsockopt)",
+	.insns = {
+		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+			     BPF_FUNC_get_netns_cookie),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_CGROUP_SOCKOPT,
+	.expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+	.result = ACCEPT,
+},
+{
+	"pass ctx or null check, 10: null (cgroup/setsockopt)",
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_1, 0),
+		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+			     BPF_FUNC_get_netns_cookie),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_CGROUP_SOCKOPT,
+	.expected_attach_type = BPF_CGROUP_SETSOCKOPT,
+	.result = ACCEPT,
+},