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    Subject[PATCH v11 7/9] selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put()
    Date
    Add verifier tests for bpf_lookup_*_key() and bpf_key_put(), to ensure that
    acquired key references stored in the bpf_key structure are released, that
    a non-NULL bpf_key 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/config | 1 +
    tools/testing/selftests/bpf/test_verifier.c | 3 +-
    .../selftests/bpf/verifier/ref_tracking.c | 139 ++++++++++++++++++
    3 files changed, 142 insertions(+), 1 deletion(-)

    diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
    index fabf0c014349..c99b196aa840 100644
    --- a/tools/testing/selftests/bpf/config
    +++ b/tools/testing/selftests/bpf/config
    @@ -30,6 +30,7 @@ CONFIG_IPV6_GRE=y
    CONFIG_IPV6_SEG6_BPF=y
    CONFIG_IPV6_SIT=m
    CONFIG_IPV6_TUNNEL=y
    +CONFIG_KEYS=y
    CONFIG_LIRC=y
    CONFIG_LWTUNNEL=y
    CONFIG_MPLS=y
    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..f18ce867271f 100644
    --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c
    +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c
    @@ -84,6 +84,145 @@
    .errstr = "Unreleased reference",
    .result = REJECT,
    },
    +{
    + "reference tracking: acquire/release user key reference",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, -3),
    + BPF_MOV64_IMM(BPF_REG_2, 0),
    + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
    + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
    + 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_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,
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_user_key", 2 },
    + { "bpf_key_put", 5 },
    + },
    + .result = ACCEPT,
    +},
    +{
    + "reference tracking: acquire/release system key reference",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, 1),
    + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
    + BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 2),
    + 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_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,
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_system_key", 1 },
    + { "bpf_key_put", 4 },
    + },
    + .result = ACCEPT,
    +},
    +{
    + "reference tracking: release user key reference without check",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, -3),
    + BPF_MOV64_IMM(BPF_REG_2, 0),
    + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 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_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 = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_user_key", 2 },
    + { "bpf_key_put", 4 },
    + },
    + .result = REJECT,
    +},
    +{
    + "reference tracking: release system key reference without check",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, 1),
    + BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 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_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 = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_system_key", 1 },
    + { "bpf_key_put", 3 },
    + },
    + .result = REJECT,
    +},
    +{
    + "reference tracking: release with NULL key pointer",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, 0),
    + 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_LSM,
    + .kfunc = "bpf",
    + .expected_attach_type = BPF_LSM_MAC,
    + .flags = BPF_F_SLEEPABLE,
    + .errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
    + .fixup_kfunc_btf_id = {
    + { "bpf_key_put", 1 },
    + },
    + .result = REJECT,
    +},
    +{
    + "reference tracking: leak potential reference to user key",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, -3),
    + BPF_MOV64_IMM(BPF_REG_2, 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 = "Unreleased reference",
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_user_key", 2 },
    + },
    + .result = REJECT,
    +},
    +{
    + "reference tracking: leak potential reference to system key",
    + .insns = {
    + BPF_MOV64_IMM(BPF_REG_1, 1),
    + 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 = "Unreleased reference",
    + .fixup_kfunc_btf_id = {
    + { "bpf_lookup_system_key", 1 },
    + },
    + .result = REJECT,
    +},
    {
    "reference tracking: release reference without check",
    .insns = {
    --
    2.25.1
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      Last update: 2022-08-12 12:22    [W:2.282 / U:0.088 seconds]
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