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selftests/bpf: Add verifier tests for bpf_lookup_*_key() and bpf_key_…
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…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>
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Roberto Sassu authored and Alexei Starovoitov committed Sep 22, 2022
1 parent 94fd742 commit 7c036ed
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Showing 3 changed files with 142 additions and 1 deletion.
1 change: 1 addition & 0 deletions tools/testing/selftests/bpf/config
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Original file line number Diff line number Diff line change
Expand Up @@ -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
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3 changes: 2 additions & 1 deletion tools/testing/selftests/bpf/test_verifier.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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,
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139 changes: 139 additions & 0 deletions tools/testing/selftests/bpf/verifier/ref_tracking.c
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Expand Up @@ -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 = {
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