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selftests/bpf: Add tests for kfunc register offset checks

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Include a few verifier selftests that test against the problems being
fixed by previous commits, i.e. release kfunc always require
PTR_TO_BTF_ID fixed and var_off to be 0, and negative offset is not
permitted and returns a helpful error message.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220304224645.3677453-9-memxor@gmail.com
This commit is contained in:
Kumar Kartikeya Dwivedi 2022-03-05 04:16:45 +05:30 committed by Alexei Starovoitov
parent 0b206c6d10
commit 8218ccb5bd
2 changed files with 94 additions and 0 deletions
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11
net/bpf/test_run.c
View File

@ -270,9 +270,14 @@ struct sock * noinline bpf_kfunc_call_test3(struct sock *sk)
return sk;
}
struct prog_test_member {
u64 c;
};
struct prog_test_ref_kfunc {
int a;
int b;
struct prog_test_member memb;
struct prog_test_ref_kfunc *next;
};
@ -295,6 +300,10 @@ noinline void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
{
}
noinline void bpf_kfunc_call_memb_release(struct prog_test_member *p)
{
}
struct prog_test_pass1 {
int x0;
struct {
@ -379,6 +388,7 @@ BTF_ID(func, bpf_kfunc_call_test2)
BTF_ID(func, bpf_kfunc_call_test3)
BTF_ID(func, bpf_kfunc_call_test_acquire)
BTF_ID(func, bpf_kfunc_call_test_release)
BTF_ID(func, bpf_kfunc_call_memb_release)
BTF_ID(func, bpf_kfunc_call_test_pass_ctx)
BTF_ID(func, bpf_kfunc_call_test_pass1)
BTF_ID(func, bpf_kfunc_call_test_pass2)
@ -396,6 +406,7 @@ BTF_SET_END(test_sk_acquire_kfunc_ids)
BTF_SET_START(test_sk_release_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test_release)
BTF_ID(func, bpf_kfunc_call_memb_release)
BTF_SET_END(test_sk_release_kfunc_ids)
BTF_SET_START(test_sk_ret_null_kfunc_ids)

83
tools/testing/selftests/bpf/verifier/calls.c
View File

@ -115,6 +115,89 @@
{ "bpf_kfunc_call_test_release", 5 },
},
},
{
"calls: invalid kfunc call: reg->off must be zero when passed to release kfunc",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 8),
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_SCHED_CLS,
.result = REJECT,
.errstr = "R1 must have zero offset when passed to release func",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_memb_release", 8 },
},
},
{
"calls: invalid kfunc call: PTR_TO_BTF_ID with negative offset",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_DW, BPF_REG_1, BPF_REG_1, 16),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -4),
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_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_release", 9 },
},
.result_unpriv = REJECT,
.result = REJECT,
.errstr = "negative offset ptr_ ptr R1 off=-4 disallowed",
},
{
"calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_ST_MEM(BPF_DW, BPF_REG_1, 0, 0),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
BPF_EXIT_INSN(),
BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_0, 4),
BPF_JMP_IMM(BPF_JLE, BPF_REG_2, 4, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 3),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_MOV64_IMM(BPF_REG_0, 0),
BPF_EXIT_INSN(),
BPF_ALU64_REG(BPF_ADD, BPF_REG_1, BPF_REG_2),
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_SCHED_CLS,
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_acquire", 3 },
{ "bpf_kfunc_call_test_release", 9 },
{ "bpf_kfunc_call_test_release", 13 },
{ "bpf_kfunc_call_test_release", 17 },
},
.result_unpriv = REJECT,
.result = REJECT,
.errstr = "variable ptr_ access var_off=(0x0; 0x7) disallowed",
},
{
"calls: basic sanity",
.insns = {