selftests/bpf: Add verifier tests for trusted kfunc args

Make sure verifier rejects the bad cases and ensure the good case keeps
working. The selftests make use of the bpf_kfunc_call_test_ref kfunc
added in the previous patch only for verification.

Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220721134245.2450-11-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c
index 743ed34c12382e53c0e5f12c894a5eaf4f2cd859..3fb4f69b196237dbfcbf590bb154c6a5df766a69 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/calls.c
+++ b/tools/testing/selftests/bpf/verifier/calls.c
@@ -218,6 +218,59 @@
        .result = REJECT,
        .errstr = "variable ptr_ access var_off=(0x0; 0x7) disallowed",
 },
+{
+       "calls: invalid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID",
+       .insns = {
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+       BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_6, 16),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       .fixup_kfunc_btf_id = {
+               { "bpf_kfunc_call_test_acquire", 3 },
+               { "bpf_kfunc_call_test_ref", 8 },
+               { "bpf_kfunc_call_test_ref", 10 },
+       },
+       .result_unpriv = REJECT,
+       .result = REJECT,
+       .errstr = "R1 must be referenced",
+},
+{
+       "calls: valid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID",
+       .insns = {
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
+       BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+       BPF_EXIT_INSN(),
+       BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+       BPF_MOV64_REG(BPF_REG_1, BPF_REG_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_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       .fixup_kfunc_btf_id = {
+               { "bpf_kfunc_call_test_acquire", 3 },
+               { "bpf_kfunc_call_test_ref", 8 },
+               { "bpf_kfunc_call_test_release", 10 },
+       },
+       .result_unpriv = REJECT,
+       .result = ACCEPT,
+},
 {
        "calls: basic sanity",
        .insns = {