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selftests/bpf: Add verifier tests for kptr
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Reuse bpf_prog_test functions to test the support for PTR_TO_BTF_ID in
BPF map case, including some tests that verify implementation sanity and
corner cases.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
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@kkdwivedi
kkdwivedi authored and Kernel Patches Daemon committed Apr 11, 2022
1 parent 12e27d2 commit cdc0311
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Showing 3 changed files with 539 additions and 7 deletions.
45 changes: 40 additions & 5 deletions net/bpf/test_run.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -584,6 +584,12 @@ noinline void bpf_kfunc_call_memb_release(struct prog_test_member *p)
{
}

noinline struct prog_test_ref_kfunc *
bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **p, int a, int b)
{
return &prog_test_struct;
}

struct prog_test_pass1 {
int x0;
struct {
Expand Down Expand Up @@ -669,6 +675,7 @@ 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_kptr_get)
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)
Expand All @@ -682,6 +689,7 @@ BTF_SET_END(test_sk_check_kfunc_ids)

BTF_SET_START(test_sk_acquire_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test_acquire)
BTF_ID(func, bpf_kfunc_call_test_kptr_get)
BTF_SET_END(test_sk_acquire_kfunc_ids)

BTF_SET_START(test_sk_release_kfunc_ids)
Expand All @@ -691,8 +699,13 @@ BTF_SET_END(test_sk_release_kfunc_ids)

BTF_SET_START(test_sk_ret_null_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test_acquire)
BTF_ID(func, bpf_kfunc_call_test_kptr_get)
BTF_SET_END(test_sk_ret_null_kfunc_ids)

BTF_SET_START(test_sk_kptr_acquire_kfunc_ids)
BTF_ID(func, bpf_kfunc_call_test_kptr_get)
BTF_SET_END(test_sk_kptr_acquire_kfunc_ids)

static void *bpf_test_init(const union bpf_attr *kattr, u32 user_size,
u32 size, u32 headroom, u32 tailroom)
{
Expand Down Expand Up @@ -1579,14 +1592,36 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,

static const struct btf_kfunc_id_set bpf_prog_test_kfunc_set = {
.owner = THIS_MODULE,
.check_set = &test_sk_check_kfunc_ids,
.acquire_set = &test_sk_acquire_kfunc_ids,
.release_set = &test_sk_release_kfunc_ids,
.ret_null_set = &test_sk_ret_null_kfunc_ids,
.check_set = &test_sk_check_kfunc_ids,
.acquire_set = &test_sk_acquire_kfunc_ids,
.release_set = &test_sk_release_kfunc_ids,
.ret_null_set = &test_sk_ret_null_kfunc_ids,
.kptr_acquire_set = &test_sk_kptr_acquire_kfunc_ids
};

BTF_ID_LIST(bpf_prog_test_dtor_kfunc_ids)
BTF_ID(struct, prog_test_ref_kfunc)
BTF_ID(func, bpf_kfunc_call_test_release)
BTF_ID(struct, prog_test_member)
BTF_ID(func, bpf_kfunc_call_memb_release)

static int __init bpf_prog_test_run_init(void)
{
return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_prog_test_kfunc_set);
const struct btf_id_dtor_kfunc bpf_prog_test_dtor_kfunc[] = {
{
.btf_id = bpf_prog_test_dtor_kfunc_ids[0],
.kfunc_btf_id = bpf_prog_test_dtor_kfunc_ids[1]
},
{
.btf_id = bpf_prog_test_dtor_kfunc_ids[2],
.kfunc_btf_id = bpf_prog_test_dtor_kfunc_ids[3],
},
};
int ret;

ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_prog_test_kfunc_set);
return ret ?: register_btf_id_dtor_kfuncs(bpf_prog_test_dtor_kfunc,
ARRAY_SIZE(bpf_prog_test_dtor_kfunc),
THIS_MODULE);
}
late_initcall(bpf_prog_test_run_init);
55 changes: 53 additions & 2 deletions tools/testing/selftests/bpf/test_verifier.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@
#define MAX_INSNS BPF_MAXINSNS
#define MAX_TEST_INSNS 1000000
#define MAX_FIXUPS 8
#define MAX_NR_MAPS 22
#define MAX_NR_MAPS 23
#define MAX_TEST_RUNS 8
#define POINTER_VALUE 0xcafe4all
#define TEST_DATA_LEN 64
Expand Down Expand Up @@ -101,6 +101,7 @@ struct bpf_test {
int fixup_map_reuseport_array[MAX_FIXUPS];
int fixup_map_ringbuf[MAX_FIXUPS];
int fixup_map_timer[MAX_FIXUPS];
int fixup_map_kptr[MAX_FIXUPS];
struct kfunc_btf_id_pair fixup_kfunc_btf_id[MAX_FIXUPS];
/* Expected verifier log output for result REJECT or VERBOSE_ACCEPT.
* Can be a tab-separated sequence of expected strings. An empty string
Expand Down Expand Up @@ -621,8 +622,15 @@ static int create_cgroup_storage(bool percpu)
* struct timer {
* struct bpf_timer t;
* };
* struct btf_ptr {
* struct prog_test_ref_kfunc __kptr *ptr;
* struct prog_test_ref_kfunc __kptr_ref *ptr;
* struct prog_test_member __kptr_ref *ptr;
* }
*/
static const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l\0bpf_timer\0timer\0t";
static const char btf_str_sec[] = "\0bpf_spin_lock\0val\0cnt\0l\0bpf_timer\0timer\0t"
"\0btf_ptr\0prog_test_ref_kfunc\0ptr\0kptr\0kptr_ref"
"\0prog_test_member";
static __u32 btf_raw_types[] = {
/* int */
BTF_TYPE_INT_ENC(0, BTF_INT_SIGNED, 0, 32, 4), /* [1] */
Expand All @@ -638,6 +646,22 @@ static __u32 btf_raw_types[] = {
/* struct timer */ /* [5] */
BTF_TYPE_ENC(35, BTF_INFO_ENC(BTF_KIND_STRUCT, 0, 1), 16),
BTF_MEMBER_ENC(41, 4, 0), /* struct bpf_timer t; */
/* struct prog_test_ref_kfunc */ /* [6] */
BTF_STRUCT_ENC(51, 0, 0),
BTF_STRUCT_ENC(89, 0, 0), /* [7] */
/* type tag "kptr" */
BTF_TYPE_TAG_ENC(75, 6), /* [8] */
/* type tag "kptr_ref" */
BTF_TYPE_TAG_ENC(80, 6), /* [9] */
BTF_TYPE_TAG_ENC(80, 7), /* [10] */
BTF_PTR_ENC(8), /* [11] */
BTF_PTR_ENC(9), /* [12] */
BTF_PTR_ENC(10), /* [13] */
/* struct btf_ptr */ /* [14] */
BTF_STRUCT_ENC(43, 3, 24),
BTF_MEMBER_ENC(71, 11, 0), /* struct prog_test_ref_kfunc __kptr *ptr; */
BTF_MEMBER_ENC(71, 12, 64), /* struct prog_test_ref_kfunc __kptr_ref *ptr; */
BTF_MEMBER_ENC(71, 13, 128), /* struct prog_test_member __kptr_ref *ptr; */
};

static int load_btf(void)
Expand Down Expand Up @@ -727,6 +751,25 @@ static int create_map_timer(void)
return fd;
}

static int create_map_kptr(void)
{
LIBBPF_OPTS(bpf_map_create_opts, opts,
.btf_key_type_id = 1,
.btf_value_type_id = 14,
);
int fd, btf_fd;

btf_fd = load_btf();
if (btf_fd < 0)
return -1;

opts.btf_fd = btf_fd;
fd = bpf_map_create(BPF_MAP_TYPE_ARRAY, "test_map", 4, 24, 1, &opts);
if (fd < 0)
printf("Failed to create map with btf_id pointer\n");
return fd;
}

static char bpf_vlog[UINT_MAX >> 8];

static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
Expand Down Expand Up @@ -754,6 +797,7 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
int *fixup_map_reuseport_array = test->fixup_map_reuseport_array;
int *fixup_map_ringbuf = test->fixup_map_ringbuf;
int *fixup_map_timer = test->fixup_map_timer;
int *fixup_map_kptr = test->fixup_map_kptr;
struct kfunc_btf_id_pair *fixup_kfunc_btf_id = test->fixup_kfunc_btf_id;

if (test->fill_helper) {
Expand Down Expand Up @@ -947,6 +991,13 @@ static void do_test_fixup(struct bpf_test *test, enum bpf_prog_type prog_type,
fixup_map_timer++;
} while (*fixup_map_timer);
}
if (*fixup_map_kptr) {
map_fds[22] = create_map_kptr();
do {
prog[*fixup_map_kptr].imm = map_fds[22];
fixup_map_kptr++;
} while (*fixup_map_kptr);
}

/* Patch in kfunc BTF IDs */
if (fixup_kfunc_btf_id->kfunc) {
Expand Down
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