From: Roberto Sassu <roberto.sassu@huawei.com>

Add verifier tests to ensure that only supported dynamic pointer types are
accepted, that the passed argument is actually a dynamic pointer, and that
the passed argument is a pointer to the stack.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
 .../bpf/verifier/kfunc_dynptr_param.c         | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/verifier/kfunc_dynptr_param.c

diff --git a/tools/testing/selftests/bpf/verifier/kfunc_dynptr_param.c b/tools/testing/selftests/bpf/verifier/kfunc_dynptr_param.c
new file mode 100644
index 000000000000..8abb8d566321
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/kfunc_dynptr_param.c

@@ -0,0 +1,72 @@
+{
+       "kfunc dynamic pointer param: type not supported",
+       .insns = {
+       BPF_ST_MEM(BPF_DW, BPF_REG_10, -16, 0),
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, -16),
+       BPF_LD_MAP_FD(BPF_REG_1, 0),
+       BPF_MOV64_IMM(BPF_REG_2, 8),
+       BPF_MOV64_IMM(BPF_REG_3, 0),
+       BPF_MOV64_REG(BPF_REG_4, BPF_REG_6),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve_dynptr),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+       BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
+       BPF_MOV64_IMM(BPF_REG_3, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+       BPF_MOV64_IMM(BPF_REG_2, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_discard_dynptr),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .fixup_map_ringbuf = { 3 },
+       .prog_type = BPF_PROG_TYPE_LSM,
+       .kfunc = "bpf",
+       .expected_attach_type = BPF_LSM_MAC,
+       .flags = BPF_F_SLEEPABLE,
+       .errstr = "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type",
+       .result = REJECT,
+       .fixup_kfunc_btf_id = {
+               { "bpf_verify_pkcs7_signature", 12 },
+       },
+},
+{
+       "kfunc dynamic pointer param: arg not a dynamic pointer",
+       .insns = {
+       BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+       BPF_MOV64_REG(BPF_REG_2, BPF_REG_1),
+       BPF_MOV64_IMM(BPF_REG_3, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_LSM,
+       .kfunc = "bpf",
+       .expected_attach_type = BPF_LSM_MAC,
+       .flags = BPF_F_SLEEPABLE,
+       .errstr = "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized",
+       .result = REJECT,
+       .fixup_kfunc_btf_id = {
+               { "bpf_verify_pkcs7_signature", 5 },
+       },
+},
+{
+       "kfunc dynamic pointer param: arg not a pointer to stack",
+       .insns = {
+       BPF_MOV64_IMM(BPF_REG_1, 0),
+       BPF_MOV64_IMM(BPF_REG_2, 0),
+       BPF_MOV64_IMM(BPF_REG_3, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_LSM,
+       .kfunc = "bpf",
+       .expected_attach_type = BPF_LSM_MAC,
+       .flags = BPF_F_SLEEPABLE,
+       .errstr = "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack",
+       .result = REJECT,
+       .fixup_kfunc_btf_id = {
+               { "bpf_verify_pkcs7_signature", 3 },
+       },
+},