bpf: Add selftest cases for ctx_or_null argument type

Add various tests to make sure the verifier keeps catching them:

  # ./test_verifier
  [...]
  #230/p pass ctx or null check, 1: ctx OK
  #231/p pass ctx or null check, 2: null OK
  #232/p pass ctx or null check, 3: 1 OK
  #233/p pass ctx or null check, 4: ctx - const OK
  #234/p pass ctx or null check, 5: null (connect) OK
  #235/p pass ctx or null check, 6: null (bind) OK
  #236/p pass ctx or null check, 7: ctx (bind) OK
  #237/p pass ctx or null check, 8: null (bind) OK
  [...]
  Summary: 1595 PASSED, 0 SKIPPED, 0 FAILED

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/c74758d07b1b678036465ef7f068a49e9efd3548.1585323121.git.daniel@iogearbox.net

diff --git a/tools/testing/selftests/bpf/verifier/ctx.c b/tools/testing/selftests/bpf/verifier/ctx.c
index 92762c0..93d6b16 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/ctx.c
+++ b/tools/testing/selftests/bpf/verifier/ctx.c
@@ -91,3 +91,108 @@
        .result = REJECT,
        .errstr = "variable ctx access var_off=(0x0; 0x4)",
 },
+{
+       "pass ctx or null check, 1: ctx",
+       .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_SOCK_ADDR,
+       .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG,
+       .result = ACCEPT,
+},
+{
+       "pass ctx or null check, 2: null",
+       .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_SOCK_ADDR,
+       .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG,
+       .result = ACCEPT,
+},
+{
+       "pass ctx or null check, 3: 1",
+       .insns = {
+               BPF_MOV64_IMM(BPF_REG_1, 1),
+               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_SOCK_ADDR,
+       .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG,
+       .result = REJECT,
+       .errstr = "R1 type=inv expected=ctx",
+},
+{
+       "pass ctx or null check, 4: ctx - const",
+       .insns = {
+               BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -612),
+               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_SOCK_ADDR,
+       .expected_attach_type = BPF_CGROUP_UDP6_SENDMSG,
+       .result = REJECT,
+       .errstr = "dereference of modified ctx ptr",
+},
+{
+       "pass ctx or null check, 5: null (connect)",
+       .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_SOCK_ADDR,
+       .expected_attach_type = BPF_CGROUP_INET4_CONNECT,
+       .result = ACCEPT,
+},
+{
+       "pass ctx or null check, 6: null (bind)",
+       .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_SOCK,
+       .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
+       .result = ACCEPT,
+},
+{
+       "pass ctx or null check, 7: ctx (bind)",
+       .insns = {
+               BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                            BPF_FUNC_get_socket_cookie),
+               BPF_MOV64_IMM(BPF_REG_0, 0),
+               BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_CGROUP_SOCK,
+       .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
+       .result = ACCEPT,
+},
+{
+       "pass ctx or null check, 8: null (bind)",
+       .insns = {
+               BPF_MOV64_IMM(BPF_REG_1, 0),
+               BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+                            BPF_FUNC_get_socket_cookie),
+               BPF_MOV64_IMM(BPF_REG_0, 0),
+               BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_CGROUP_SOCK,
+       .expected_attach_type = BPF_CGROUP_INET4_POST_BIND,
+       .result = REJECT,
+       .errstr = "R1 type=inv expected=ctx",
+},