Add verifier tests for bpf_lookup_user_key() and bpf_key_put(), to ensure that acquired key references can be released, that a non-NULL pointer is passed to bpf_key_put(), and that key references are not leaked.
Also, slightly modify test_verifier.c, to find the BTF ID of the attach point for the LSM program type (currently, it is done only for TRACING).
Signed-off-by: Roberto Sassu roberto.sassu@huawei.com --- tools/testing/selftests/bpf/test_verifier.c | 3 +- .../selftests/bpf/verifier/ref_tracking.c | 66 +++++++++++++++++++ 2 files changed, 68 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c index f9d553fbf68a..2dbcbf363c18 100644 --- a/tools/testing/selftests/bpf/test_verifier.c +++ b/tools/testing/selftests/bpf/test_verifier.c @@ -1498,7 +1498,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv, opts.log_level = DEFAULT_LIBBPF_LOG_LEVEL; opts.prog_flags = pflags;
- if (prog_type == BPF_PROG_TYPE_TRACING && test->kfunc) { + if ((prog_type == BPF_PROG_TYPE_TRACING || + prog_type == BPF_PROG_TYPE_LSM) && test->kfunc) { int attach_btf_id;
attach_btf_id = libbpf_find_vmlinux_btf_id(test->kfunc, diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c index 57a83d763ec1..36e0b9b342de 100644 --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c @@ -84,6 +84,72 @@ .errstr = "Unreleased reference", .result = REJECT, }, +{ + "reference tracking: release key reference", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, -3), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_lookup_user_key), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_EMIT_CALL(BPF_FUNC_key_put), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_LSM, + .kfunc = "bpf", + .expected_attach_type = BPF_LSM_MAC, + .flags = BPF_F_SLEEPABLE, + .result = ACCEPT, +}, +{ + "reference tracking: release key reference without check", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, -3), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_lookup_user_key), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_0), + BPF_EMIT_CALL(BPF_FUNC_key_put), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_LSM, + .kfunc = "bpf", + .expected_attach_type = BPF_LSM_MAC, + .flags = BPF_F_SLEEPABLE, + .errstr = "type=ptr_or_null_ expected=ptr_", + .result = REJECT, +}, +{ + "reference tracking: release reference with NULL key pointer", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, 0), + BPF_EMIT_CALL(BPF_FUNC_key_put), + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_LSM, + .kfunc = "bpf", + .expected_attach_type = BPF_LSM_MAC, + .flags = BPF_F_SLEEPABLE, + .errstr = "type=scalar expected=ptr_", + .result = REJECT, +}, +{ + "reference tracking: leak potential reference to key", + .insns = { + BPF_MOV64_IMM(BPF_REG_1, -3), + BPF_MOV64_IMM(BPF_REG_2, 0), + BPF_EMIT_CALL(BPF_FUNC_lookup_user_key), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_LSM, + .kfunc = "bpf", + .expected_attach_type = BPF_LSM_MAC, + .flags = BPF_F_SLEEPABLE, + .errstr = "Unreleased reference", + .result = REJECT, +}, { "reference tracking: release reference without check", .insns = {