Exercise verifier access checks for bpf_sk_lookup context fields.
Signed-off-by: Jakub Sitnicki <ja...@cloudflare.com>
---
Notes:
v3:
- Consolidate ACCEPT tests into one.
- Deduplicate REJECT tests and arrange them into logical groups.
- Add tests for out-of-bounds and unaligned access.
- Cover access to newly introduced 'sk' field.
v2:
- Adjust for fields renames in struct bpf_sk_lookup.
.../selftests/bpf/verifier/ctx_sk_lookup.c | 219 ++++++++++++++++++
1 file changed, 219 insertions(+)
create mode 100644 tools/testing/selftests/bpf/verifier/ctx_sk_lookup.c
diff --git a/tools/testing/selftests/bpf/verifier/ctx_sk_lookup.c
b/tools/testing/selftests/bpf/verifier/ctx_sk_lookup.c
new file mode 100644
index 000000000000..9542b07892ad
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/ctx_sk_lookup.c
@@ -0,0 +1,219 @@
+{
+ "valid 4-byte read from bpf_sk_lookup",
+ .insns = {
+ /* 4-byte read from family field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, family)),
+ /* 4-byte read from protocol field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, protocol)),
+ /* 4-byte read from remote_ip4 field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_ip4)),
+ /* 4-byte read from remote_ip6 field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_ip6[0])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_ip6[1])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_ip6[2])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_ip6[3])),
+ /* 4-byte read from remote_port field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, remote_port)),
+ /* 4-byte read from local_ip4 field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_ip4)),
+ /* 4-byte read from local_ip6 field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_ip6[0])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_ip6[1])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_ip6[2])),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_ip6[3])),
+ /* 4-byte read from local_port field */
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, local_port)),
+ /* 8-byte read from sk field */
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, sk)),
+ BPF_EXIT_INSN(),
+ },
+ .result = ACCEPT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+/* invalid size reads from a 4-byte field in bpf_sk_lookup */
+{
+ "invalid 8-byte read from bpf_sk_lookup family field",
+ .insns = {
+ BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, family)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 2-byte read from bpf_sk_lookup family field",
+ .insns = {
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, family)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 1-byte read from bpf_sk_lookup family field",
+ .insns = {
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, family)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+/* invalid size reads from an 8-byte field in bpf_sk_lookup */
+{
+ "invalid 4-byte read from bpf_sk_lookup sk field",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, sk)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 2-byte read from bpf_sk_lookup sk field",
+ .insns = {
+ BPF_LDX_MEM(BPF_H, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, sk)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 1-byte read from bpf_sk_lookup sk field",
+ .insns = {
+ BPF_LDX_MEM(BPF_B, BPF_REG_0, BPF_REG_1,
+ offsetof(struct bpf_sk_lookup, sk)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+/* out of bounds and unaligned reads from bpf_sk_lookup */
+{
+ "invalid 4-byte read past end of bpf_sk_lookup",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+ sizeof(struct bpf_sk_lookup)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 4-byte unaligned read from bpf_sk_lookup at odd offset",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 1),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 4-byte unaligned read from bpf_sk_lookup at even offset",
+ .insns = {
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1, 2),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+/* writes to and out of bounds of bpf_sk_lookup */
+{
+ "invalid 8-byte write to bpf_sk_lookup",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0xcafe4a11U),
+ BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 4-byte write to bpf_sk_lookup",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0xcafe4a11U),
+ BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 2-byte write to bpf_sk_lookup",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0xcafe4a11U),
+ BPF_STX_MEM(BPF_H, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 1-byte write to bpf_sk_lookup",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0xcafe4a11U),
+ BPF_STX_MEM(BPF_B, BPF_REG_1, BPF_REG_0, 0),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
+{
+ "invalid 4-byte write past end of bpf_sk_lookup",
+ .insns = {
+ BPF_MOV64_IMM(BPF_REG_0, 0xcafe4a11U),
+ BPF_STX_MEM(BPF_W, BPF_REG_1, BPF_REG_0,
+ sizeof(struct bpf_sk_lookup)),
+ BPF_EXIT_INSN(),
+ },
+ .errstr = "invalid bpf_context access",
+ .result = REJECT,
+ .prog_type = BPF_PROG_TYPE_SK_LOOKUP,
+ .expected_attach_type = BPF_SK_LOOKUP,
+},
--
2.25.4
