selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_put()

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>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20220920075951.929132-11-roberto.sassu@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config
index 0fdd11e..add5a5a 100644 (file)
--- 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 f9d553f..2dbcbf3 100644 (file)
--- 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 57a83d7..f18ce86 100644 (file)
--- 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 = {