2022-09-05 15:13:54

by Roberto Sassu

Subject: [PATCH v16 09/12] selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put()

From: Roberto Sassu <[email protected]>

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 <[email protected]>
---
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 0fdd11e6b742..add5a5a919b4 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=y
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

2022-09-06 03:27:43

by Kumar Kartikeya Dwivedi

Subject: Re: [PATCH v16 09/12] selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put()

On Mon, 5 Sept 2022 at 16:36, Roberto Sassu
<[email protected]> wrote:
>
> From: Roberto Sassu <[email protected]>
>
> 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 <[email protected]>
> ---

Acked-by: Kumar Kartikeya Dwivedi <[email protected]>

> 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 0fdd11e6b742..add5a5a919b4 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=y
> 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
>