linuxdebug/tools/testing/selftests/bpf/progs/dynptr_fail.c

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2024-07-16 15:50:57 +02:00
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Facebook */
#include <errno.h>
#include <string.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
struct test_info {
int x;
struct bpf_dynptr ptr;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, struct bpf_dynptr);
} array_map1 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, struct test_info);
} array_map2 SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u32);
} array_map3 SEC(".maps");
struct sample {
int pid;
long value;
char comm[16];
};
struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);
} ringbuf SEC(".maps");
int err, val;
static int get_map_val_dynptr(struct bpf_dynptr *ptr)
{
__u32 key = 0, *map_val;
bpf_map_update_elem(&array_map3, &key, &val, 0);
map_val = bpf_map_lookup_elem(&array_map3, &key);
if (!map_val)
return -ENOENT;
bpf_dynptr_from_mem(map_val, sizeof(*map_val), 0, ptr);
return 0;
}
/* Every bpf_ringbuf_reserve_dynptr call must have a corresponding
* bpf_ringbuf_submit/discard_dynptr call
*/
SEC("?raw_tp")
int ringbuf_missing_release1(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
/* missing a call to bpf_ringbuf_discard/submit_dynptr */
return 0;
}
SEC("?raw_tp")
int ringbuf_missing_release2(void *ctx)
{
struct bpf_dynptr ptr1, ptr2;
struct sample *sample;
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr1);
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr2);
sample = bpf_dynptr_data(&ptr1, 0, sizeof(*sample));
if (!sample) {
bpf_ringbuf_discard_dynptr(&ptr1, 0);
bpf_ringbuf_discard_dynptr(&ptr2, 0);
return 0;
}
bpf_ringbuf_submit_dynptr(&ptr1, 0);
/* missing a call to bpf_ringbuf_discard/submit_dynptr on ptr2 */
return 0;
}
static int missing_release_callback_fn(__u32 index, void *data)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
/* missing a call to bpf_ringbuf_discard/submit_dynptr */
return 0;
}
/* Any dynptr initialized within a callback must have bpf_dynptr_put called */
SEC("?raw_tp")
int ringbuf_missing_release_callback(void *ctx)
{
bpf_loop(10, missing_release_callback_fn, NULL, 0);
return 0;
}
/* Can't call bpf_ringbuf_submit/discard_dynptr on a non-initialized dynptr */
SEC("?raw_tp")
int ringbuf_release_uninit_dynptr(void *ctx)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/* A dynptr can't be used after it has been invalidated */
SEC("?raw_tp")
int use_after_invalid(void *ctx)
{
struct bpf_dynptr ptr;
char read_data[64];
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(read_data), 0, &ptr);
bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
bpf_ringbuf_submit_dynptr(&ptr, 0);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
return 0;
}
/* Can't call non-dynptr ringbuf APIs on a dynptr ringbuf sample */
SEC("?raw_tp")
int ringbuf_invalid_api(void *ctx)
{
struct bpf_dynptr ptr;
struct sample *sample;
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr);
sample = bpf_dynptr_data(&ptr, 0, sizeof(*sample));
if (!sample)
goto done;
sample->pid = 123;
/* invalid API use. need to use dynptr API to submit/discard */
bpf_ringbuf_submit(sample, 0);
done:
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* Can't add a dynptr to a map */
SEC("?raw_tp")
int add_dynptr_to_map1(void *ctx)
{
struct bpf_dynptr ptr;
int key = 0;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
/* this should fail */
bpf_map_update_elem(&array_map1, &key, &ptr, 0);
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/* Can't add a struct with an embedded dynptr to a map */
SEC("?raw_tp")
int add_dynptr_to_map2(void *ctx)
{
struct test_info x;
int key = 0;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &x.ptr);
/* this should fail */
bpf_map_update_elem(&array_map2, &key, &x, 0);
bpf_ringbuf_submit_dynptr(&x.ptr, 0);
return 0;
}
/* A data slice can't be accessed out of bounds */
SEC("?raw_tp")
int data_slice_out_of_bounds_ringbuf(void *ctx)
{
struct bpf_dynptr ptr;
void *data;
bpf_ringbuf_reserve_dynptr(&ringbuf, 8, 0, &ptr);
data = bpf_dynptr_data(&ptr, 0, 8);
if (!data)
goto done;
/* can't index out of bounds of the data slice */
val = *((char *)data + 8);
done:
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
SEC("?raw_tp")
int data_slice_out_of_bounds_map_value(void *ctx)
{
__u32 key = 0, map_val;
struct bpf_dynptr ptr;
void *data;
get_map_val_dynptr(&ptr);
data = bpf_dynptr_data(&ptr, 0, sizeof(map_val));
if (!data)
return 0;
/* can't index out of bounds of the data slice */
val = *((char *)data + (sizeof(map_val) + 1));
return 0;
}
/* A data slice can't be used after it has been released */
SEC("?raw_tp")
int data_slice_use_after_release1(void *ctx)
{
struct bpf_dynptr ptr;
struct sample *sample;
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr);
sample = bpf_dynptr_data(&ptr, 0, sizeof(*sample));
if (!sample)
goto done;
sample->pid = 123;
bpf_ringbuf_submit_dynptr(&ptr, 0);
/* this should fail */
val = sample->pid;
return 0;
done:
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* A data slice can't be used after it has been released.
*
* This tests the case where the data slice tracks a dynptr (ptr2)
* that is at a non-zero offset from the frame pointer (ptr1 is at fp,
* ptr2 is at fp - 16).
*/
SEC("?raw_tp")
int data_slice_use_after_release2(void *ctx)
{
struct bpf_dynptr ptr1, ptr2;
struct sample *sample;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr1);
bpf_ringbuf_reserve_dynptr(&ringbuf, sizeof(*sample), 0, &ptr2);
sample = bpf_dynptr_data(&ptr2, 0, sizeof(*sample));
if (!sample)
goto done;
sample->pid = 23;
bpf_ringbuf_submit_dynptr(&ptr2, 0);
/* this should fail */
sample->pid = 23;
bpf_ringbuf_submit_dynptr(&ptr1, 0);
return 0;
done:
bpf_ringbuf_discard_dynptr(&ptr2, 0);
bpf_ringbuf_discard_dynptr(&ptr1, 0);
return 0;
}
/* A data slice must be first checked for NULL */
SEC("?raw_tp")
int data_slice_missing_null_check1(void *ctx)
{
struct bpf_dynptr ptr;
void *data;
bpf_ringbuf_reserve_dynptr(&ringbuf, 8, 0, &ptr);
data = bpf_dynptr_data(&ptr, 0, 8);
/* missing if (!data) check */
/* this should fail */
*(__u8 *)data = 3;
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/* A data slice can't be dereferenced if it wasn't checked for null */
SEC("?raw_tp")
int data_slice_missing_null_check2(void *ctx)
{
struct bpf_dynptr ptr;
__u64 *data1, *data2;
bpf_ringbuf_reserve_dynptr(&ringbuf, 16, 0, &ptr);
data1 = bpf_dynptr_data(&ptr, 0, 8);
data2 = bpf_dynptr_data(&ptr, 0, 8);
if (data1)
/* this should fail */
*data2 = 3;
done:
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* Can't pass in a dynptr as an arg to a helper function that doesn't take in a
* dynptr argument
*/
SEC("?raw_tp")
int invalid_helper1(void *ctx)
{
struct bpf_dynptr ptr;
get_map_val_dynptr(&ptr);
/* this should fail */
bpf_strncmp((const char *)&ptr, sizeof(ptr), "hello!");
return 0;
}
/* A dynptr can't be passed into a helper function at a non-zero offset */
SEC("?raw_tp")
int invalid_helper2(void *ctx)
{
struct bpf_dynptr ptr;
char read_data[64];
get_map_val_dynptr(&ptr);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 8, 0, 0);
return 0;
}
/* A bpf_dynptr is invalidated if it's been written into */
SEC("?raw_tp")
int invalid_write1(void *ctx)
{
struct bpf_dynptr ptr;
void *data;
__u8 x = 0;
get_map_val_dynptr(&ptr);
memcpy(&ptr, &x, sizeof(x));
/* this should fail */
data = bpf_dynptr_data(&ptr, 0, 1);
return 0;
}
/*
* A bpf_dynptr can't be used as a dynptr if it has been written into at a fixed
* offset
*/
SEC("?raw_tp")
int invalid_write2(void *ctx)
{
struct bpf_dynptr ptr;
char read_data[64];
__u8 x = 0;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr);
memcpy((void *)&ptr + 8, &x, sizeof(x));
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/*
* A bpf_dynptr can't be used as a dynptr if it has been written into at a
* non-const offset
*/
SEC("?raw_tp")
int invalid_write3(void *ctx)
{
struct bpf_dynptr ptr;
char stack_buf[16];
unsigned long len;
__u8 x = 0;
bpf_ringbuf_reserve_dynptr(&ringbuf, 8, 0, &ptr);
memcpy(stack_buf, &val, sizeof(val));
len = stack_buf[0] & 0xf;
memcpy((void *)&ptr + len, &x, sizeof(x));
/* this should fail */
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
static int invalid_write4_callback(__u32 index, void *data)
{
*(__u32 *)data = 123;
return 0;
}
/* If the dynptr is written into in a callback function, it should
* be invalidated as a dynptr
*/
SEC("?raw_tp")
int invalid_write4(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr);
bpf_loop(10, invalid_write4_callback, &ptr, 0);
/* this should fail */
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/* A globally-defined bpf_dynptr can't be used (it must reside as a stack frame) */
struct bpf_dynptr global_dynptr;
SEC("?raw_tp")
int global(void *ctx)
{
/* this should fail */
bpf_ringbuf_reserve_dynptr(&ringbuf, 16, 0, &global_dynptr);
bpf_ringbuf_discard_dynptr(&global_dynptr, 0);
return 0;
}
/* A direct read should fail */
SEC("?raw_tp")
int invalid_read1(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr);
/* this should fail */
val = *(int *)&ptr;
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* A direct read at an offset should fail */
SEC("?raw_tp")
int invalid_read2(void *ctx)
{
struct bpf_dynptr ptr;
char read_data[64];
get_map_val_dynptr(&ptr);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), (void *)&ptr + 1, 0, 0);
return 0;
}
/* A direct read at an offset into the lower stack slot should fail */
SEC("?raw_tp")
int invalid_read3(void *ctx)
{
struct bpf_dynptr ptr1, ptr2;
bpf_ringbuf_reserve_dynptr(&ringbuf, 16, 0, &ptr1);
bpf_ringbuf_reserve_dynptr(&ringbuf, 16, 0, &ptr2);
/* this should fail */
memcpy(&val, (void *)&ptr1 + 8, sizeof(val));
bpf_ringbuf_discard_dynptr(&ptr1, 0);
bpf_ringbuf_discard_dynptr(&ptr2, 0);
return 0;
}
static int invalid_read4_callback(__u32 index, void *data)
{
/* this should fail */
val = *(__u32 *)data;
return 0;
}
/* A direct read within a callback function should fail */
SEC("?raw_tp")
int invalid_read4(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr);
bpf_loop(10, invalid_read4_callback, &ptr, 0);
bpf_ringbuf_submit_dynptr(&ptr, 0);
return 0;
}
/* Initializing a dynptr on an offset should fail */
SEC("?raw_tp")
int invalid_offset(void *ctx)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr + 1);
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* Can't release a dynptr twice */
SEC("?raw_tp")
int release_twice(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 16, 0, &ptr);
bpf_ringbuf_discard_dynptr(&ptr, 0);
/* this second release should fail */
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
static int release_twice_callback_fn(__u32 index, void *data)
{
/* this should fail */
bpf_ringbuf_discard_dynptr(data, 0);
return 0;
}
/* Test that releasing a dynptr twice, where one of the releases happens
* within a calback function, fails
*/
SEC("?raw_tp")
int release_twice_callback(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 32, 0, &ptr);
bpf_ringbuf_discard_dynptr(&ptr, 0);
bpf_loop(10, release_twice_callback_fn, &ptr, 0);
return 0;
}
/* Reject unsupported local mem types for dynptr_from_mem API */
SEC("?raw_tp")
int dynptr_from_mem_invalid_api(void *ctx)
{
struct bpf_dynptr ptr;
int x = 0;
/* this should fail */
bpf_dynptr_from_mem(&x, sizeof(x), 0, &ptr);
return 0;
}