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selftests/bpf: Extend kfunc selftests
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Use the prog_test kfuncs to test the referenced PTR_TO_BTF_ID kfunc
support, and PTR_TO_CTX, PTR_TO_MEM argument passing support. Also
testing the various failure cases for invalid kfunc prototypes.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
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@kkdwivedi
kkdwivedi authored and Nobody committed Dec 31, 2021
1 parent 208962e commit 00d4316
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Showing 4 changed files with 241 additions and 2 deletions.
110 changes: 110 additions & 0 deletions net/bpf/test_run.c
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Original file line number Diff line number Diff line change
Expand Up @@ -232,6 +232,105 @@ struct sock * noinline bpf_kfunc_call_test3(struct sock *sk)
return sk;
}

struct prog_test_ref_kfunc {
int a;
int b;
struct prog_test_ref_kfunc *next;
};

static struct prog_test_ref_kfunc prog_test_struct = {
.a = 42,
.b = 108,
.next = &prog_test_struct,
};

noinline struct prog_test_ref_kfunc *
bpf_kfunc_call_test_acquire(unsigned long *scalar_ptr)
{
/* randomly return NULL */
if (get_jiffies_64() % 2)
return NULL;
return &prog_test_struct;
}

noinline void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p)
{
}

struct prog_test_pass1 {
int x0;
struct {
int x1;
struct {
int x2;
struct {
int x3;
};
};
};
};

struct prog_test_pass2 {
int len;
short arr1[4];
struct {
char arr2[4];
unsigned long arr3[8];
} x;
};

struct prog_test_fail1 {
void *p;
int x;
};

struct prog_test_fail2 {
int x8;
struct prog_test_pass1 x;
};

struct prog_test_fail3 {
int len;
char arr1[2];
char arr2[0];
};

noinline void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb)
{
}

noinline void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p)
{
}

noinline void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p)
{
}

noinline void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p)
{
}

noinline void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p)
{
}

noinline void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p)
{
}

noinline void bpf_kfunc_call_test_mem_len_pass1(void *mem, int mem__sz)
{
}

noinline void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len)
{
}

noinline void bpf_kfunc_call_test_mem_len_fail2(u64 *mem, int len)
{
}

__diag_pop();

ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO);
Expand All @@ -240,6 +339,17 @@ BTF_KFUNC_SET_START(tc, check, test_sk_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test1)
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_test_pass_ctx)
BTF_ID(func, bpf_kfunc_call_test_pass1)
BTF_ID(func, bpf_kfunc_call_test_pass2)
BTF_ID(func, bpf_kfunc_call_test_fail1)
BTF_ID(func, bpf_kfunc_call_test_fail2)
BTF_ID(func, bpf_kfunc_call_test_fail3)
BTF_ID(func, bpf_kfunc_call_test_mem_len_pass1)
BTF_ID(func, bpf_kfunc_call_test_mem_len_fail1)
BTF_ID(func, bpf_kfunc_call_test_mem_len_fail2)
BTF_KFUNC_SET_END(tc, check, test_sk_kfunc_ids)

static void *bpf_test_init(const union bpf_attr *kattr, u32 size,
Expand Down
6 changes: 6 additions & 0 deletions tools/testing/selftests/bpf/prog_tests/kfunc_call.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,12 @@ static void test_main(void)
ASSERT_OK(err, "bpf_prog_test_run(test2)");
ASSERT_EQ(retval, 3, "test2-retval");

prog_fd = skel->progs.kfunc_call_test_ref_btf_id.prog_fd;
err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
NULL, NULL, (__u32 *)&retval, NULL);
ASSERT_OK(err, "bpf_prog_test_run(test_ref_btf_id)");
ASSERT_EQ(retval, 0, "test_ref_btf_id-retval");

kfunc_call_test_lskel__destroy(skel);
}

Expand Down
52 changes: 50 additions & 2 deletions tools/testing/selftests/bpf/progs/kfunc_call_test.c
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Original file line number Diff line number Diff line change
@@ -1,13 +1,20 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Facebook */
#include <linux/bpf.h>
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include "bpf_tcp_helpers.h"

extern int bpf_kfunc_call_test2(struct sock *sk, __u32 a, __u32 b) __ksym;
extern __u64 bpf_kfunc_call_test1(struct sock *sk, __u32 a, __u64 b,
__u32 c, __u64 d) __ksym;

extern struct prog_test_ref_kfunc *bpf_kfunc_call_test_acquire(unsigned long *sp) __ksym;
extern void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
extern void bpf_kfunc_call_test_pass_ctx(struct __sk_buff *skb) __ksym;
extern void bpf_kfunc_call_test_pass1(struct prog_test_pass1 *p) __ksym;
extern void bpf_kfunc_call_test_pass2(struct prog_test_pass2 *p) __ksym;
extern void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
extern void bpf_kfunc_call_test_mem_len_fail2(__u64 *mem, int len) __ksym;

SEC("tc")
int kfunc_call_test2(struct __sk_buff *skb)
{
Expand Down Expand Up @@ -44,4 +51,45 @@ int kfunc_call_test1(struct __sk_buff *skb)
return ret;
}

SEC("tc")
int kfunc_call_test_ref_btf_id(struct __sk_buff *skb)
{
struct prog_test_ref_kfunc *pt;
unsigned long s = 0;
int ret = 0;

pt = bpf_kfunc_call_test_acquire(&s);
if (pt) {
if (pt->a != 42 || pt->b != 108)
ret = -1;
bpf_kfunc_call_test_release(pt);
}
return ret;
}

SEC("tc")
int kfunc_call_test_pass(struct __sk_buff *skb)
{
struct prog_test_pass1 p1 = {};
struct prog_test_pass2 p2 = {};
short a = 0;
__u64 b = 0;
long c = 0;
char d = 0;
int e = 0;

bpf_kfunc_call_test_pass_ctx(skb);
bpf_kfunc_call_test_pass1(&p1);
bpf_kfunc_call_test_pass2(&p2);

bpf_kfunc_call_test_mem_len_pass1(&a, sizeof(a));
bpf_kfunc_call_test_mem_len_pass1(&b, sizeof(b));
bpf_kfunc_call_test_mem_len_pass1(&c, sizeof(c));
bpf_kfunc_call_test_mem_len_pass1(&d, sizeof(d));
bpf_kfunc_call_test_mem_len_pass1(&e, sizeof(e));
bpf_kfunc_call_test_mem_len_fail2(&b, -1);

return 0;
}

char _license[] SEC("license") = "GPL";
75 changes: 75 additions & 0 deletions tools/testing/selftests/bpf/verifier/calls.c
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,81 @@
.prog_type = BPF_PROG_TYPE_TRACEPOINT,
.result = ACCEPT,
},
{
"calls: invalid kfunc call: ptr_to_mem to struct with non-scalar",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type STRUCT prog_test_fail1 must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail1", 2 },
},
},
{
"calls: invalid kfunc call: ptr_to_mem to struct with nesting depth > 4",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "max struct nesting depth exceeded\narg#0 pointer type STRUCT prog_test_fail2",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail2", 2 },
},
},
{
"calls: invalid kfunc call: ptr_to_mem to struct with FAM",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type STRUCT prog_test_fail3 must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_fail3", 2 },
},
},
{
"calls: invalid kfunc call: reg->type != PTR_TO_CTX",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 expected pointer to ctx, but got PTR",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_pass_ctx", 2 },
},
},
{
"calls: invalid kfunc call: void * not allowed in func proto without mem size arg",
.insns = {
BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -8),
BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, BPF_PSEUDO_KFUNC_CALL, 0, 0),
BPF_EXIT_INSN(),
},
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = REJECT,
.errstr = "arg#0 pointer type UNKNOWN must point to scalar",
.fixup_kfunc_btf_id = {
{ "bpf_kfunc_call_test_mem_len_fail1", 2 },
},
},
{
"calls: basic sanity",
.insns = {
Expand Down

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