// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Facebook */
#include <errno.h>
#include <string.h>
#include <stdbool.h>
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <linux/if_ether.h>
#include "bpf_misc.h"
#include "bpf_kfuncs.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 {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, __u32);
__type(value, __u64);
} array_map4 SEC(".maps");
struct sample {
int pid;
long value;
char comm[16];
};
struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);
__uint(max_entries, 4096);
} 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")
__failure __msg("Unreleased reference id=2")
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")
__failure __msg("Unreleased reference id=4")
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")
__failure __msg("Unreleased reference id")
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")
__failure __msg("arg 1 is an unacquired reference")
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")
__failure __msg("Expected an initialized dynptr as arg #3")
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")
__failure __msg("type=mem expected=ringbuf_mem")
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")
__failure __msg("invalid indirect read from stack")
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")
__failure __msg("invalid indirect read from stack")
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")
__failure __msg("value is outside of the allowed memory range")
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;
}
/* A data slice can't be accessed out of bounds */
SEC("?tc")
__failure __msg("value is outside of the allowed memory range")
int data_slice_out_of_bounds_skb(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
/* this should fail */
*(__u8*)(hdr + 1) = 1;
return SK_PASS;
}
SEC("?raw_tp")
__failure __msg("value is outside of the allowed memory range")
int data_slice_out_of_bounds_map_value(void *ctx)
{
__u32 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")
__failure __msg("invalid mem access 'scalar'")
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")
__failure __msg("invalid mem access 'scalar'")
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")
__failure __msg("invalid mem access 'mem_or_null'")
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")
__failure __msg("invalid mem access 'mem_or_null'")
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;
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")
__failure __msg("invalid indirect read from stack")
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")
__failure __msg("cannot pass in dynptr at an offset=-8")
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")
__failure __msg("Expected an initialized dynptr as arg #1")
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);
__sink(data);
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")
__failure __msg("cannot overwrite referenced dynptr")
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")
__failure __msg("cannot overwrite referenced dynptr")
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")
__failure __msg("cannot overwrite referenced dynptr")
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")
__failure __msg("type=map_value expected=fp")
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")
__failure __msg("invalid read from stack")
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")
__failure __msg("cannot pass in dynptr at an offset")
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")
__failure __msg("invalid read from stack")
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")
__failure __msg("invalid read from stack")
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")
__failure __msg("cannot pass in dynptr at an offset=0")
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")
__failure __msg("arg 1 is an unacquired reference")
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 callback function, fails
*/
SEC("?raw_tp")
__failure __msg("arg 1 is an unacquired reference")
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")
__failure __msg("Unsupported reg type fp for bpf_dynptr_from_mem data")
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;
}
SEC("?tc")
__failure __msg("cannot overwrite referenced dynptr") __log_level(2)
int dynptr_pruning_overwrite(struct __sk_buff *ctx)
{
asm volatile (
"r9 = 0xeB9F; \
r6 = %[ringbuf] ll; \
r1 = r6; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -16; \
call %[bpf_ringbuf_reserve_dynptr]; \
if r0 == 0 goto pjmp1; \
goto pjmp2; \
pjmp1: \
*(u64 *)(r10 - 16) = r9; \
pjmp2: \
r1 = r10; \
r1 += -16; \
r2 = 0; \
call %[bpf_ringbuf_discard_dynptr]; "
:
: __imm(bpf_ringbuf_reserve_dynptr),
__imm(bpf_ringbuf_discard_dynptr),
__imm_addr(ringbuf)
: __clobber_all
);
return 0;
}
SEC("?tc")
__success __msg("12: safe") __log_level(2)
int dynptr_pruning_stacksafe(struct __sk_buff *ctx)
{
asm volatile (
"r9 = 0xeB9F; \
r6 = %[ringbuf] ll; \
r1 = r6; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -16; \
call %[bpf_ringbuf_reserve_dynptr]; \
if r0 == 0 goto stjmp1; \
goto stjmp2; \
stjmp1: \
r9 = r9; \
stjmp2: \
r1 = r10; \
r1 += -16; \
r2 = 0; \
call %[bpf_ringbuf_discard_dynptr]; "
:
: __imm(bpf_ringbuf_reserve_dynptr),
__imm(bpf_ringbuf_discard_dynptr),
__imm_addr(ringbuf)
: __clobber_all
);
return 0;
}
SEC("?tc")
__failure __msg("cannot overwrite referenced dynptr") __log_level(2)
int dynptr_pruning_type_confusion(struct __sk_buff *ctx)
{
asm volatile (
"r6 = %[array_map4] ll; \
r7 = %[ringbuf] ll; \
r1 = r6; \
r2 = r10; \
r2 += -8; \
r9 = 0; \
*(u64 *)(r2 + 0) = r9; \
r3 = r10; \
r3 += -24; \
r9 = 0xeB9FeB9F; \
*(u64 *)(r10 - 16) = r9; \
*(u64 *)(r10 - 24) = r9; \
r9 = 0; \
r4 = 0; \
r8 = r2; \
call %[bpf_map_update_elem]; \
r1 = r6; \
r2 = r8; \
call %[bpf_map_lookup_elem]; \
if r0 != 0 goto tjmp1; \
exit; \
tjmp1: \
r8 = r0; \
r1 = r7; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -16; \
r0 = *(u64 *)(r0 + 0); \
call %[bpf_ringbuf_reserve_dynptr]; \
if r0 == 0 goto tjmp2; \
r8 = r8; \
r8 = r8; \
r8 = r8; \
r8 = r8; \
r8 = r8; \
r8 = r8; \
r8 = r8; \
goto tjmp3; \
tjmp2: \
*(u64 *)(r10 - 8) = r9; \
*(u64 *)(r10 - 16) = r9; \
r1 = r8; \
r1 += 8; \
r2 = 0; \
r3 = 0; \
r4 = r10; \
r4 += -16; \
call %[bpf_dynptr_from_mem]; \
tjmp3: \
r1 = r10; \
r1 += -16; \
r2 = 0; \
call %[bpf_ringbuf_discard_dynptr]; "
:
: __imm(bpf_map_update_elem),
__imm(bpf_map_lookup_elem),
__imm(bpf_ringbuf_reserve_dynptr),
__imm(bpf_dynptr_from_mem),
__imm(bpf_ringbuf_discard_dynptr),
__imm_addr(array_map4),
__imm_addr(ringbuf)
: __clobber_all
);
return 0;
}
SEC("?tc")
__failure __msg("dynptr has to be at a constant offset") __log_level(2)
int dynptr_var_off_overwrite(struct __sk_buff *ctx)
{
asm volatile (
"r9 = 16; \
*(u32 *)(r10 - 4) = r9; \
r8 = *(u32 *)(r10 - 4); \
if r8 >= 0 goto vjmp1; \
r0 = 1; \
exit; \
vjmp1: \
if r8 <= 16 goto vjmp2; \
r0 = 1; \
exit; \
vjmp2: \
r8 &= 16; \
r1 = %[ringbuf] ll; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -32; \
r4 += r8; \
call %[bpf_ringbuf_reserve_dynptr]; \
r9 = 0xeB9F; \
*(u64 *)(r10 - 16) = r9; \
r1 = r10; \
r1 += -32; \
r1 += r8; \
r2 = 0; \
call %[bpf_ringbuf_discard_dynptr]; "
:
: __imm(bpf_ringbuf_reserve_dynptr),
__imm(bpf_ringbuf_discard_dynptr),
__imm_addr(ringbuf)
: __clobber_all
);
return 0;
}
SEC("?tc")
__failure __msg("cannot overwrite referenced dynptr") __log_level(2)
int dynptr_partial_slot_invalidate(struct __sk_buff *ctx)
{
asm volatile (
"r6 = %[ringbuf] ll; \
r7 = %[array_map4] ll; \
r1 = r7; \
r2 = r10; \
r2 += -8; \
r9 = 0; \
*(u64 *)(r2 + 0) = r9; \
r3 = r2; \
r4 = 0; \
r8 = r2; \
call %[bpf_map_update_elem]; \
r1 = r7; \
r2 = r8; \
call %[bpf_map_lookup_elem]; \
if r0 != 0 goto sjmp1; \
exit; \
sjmp1: \
r7 = r0; \
r1 = r6; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -24; \
call %[bpf_ringbuf_reserve_dynptr]; \
*(u64 *)(r10 - 16) = r9; \
r1 = r7; \
r2 = 8; \
r3 = 0; \
r4 = r10; \
r4 += -16; \
call %[bpf_dynptr_from_mem]; \
r1 = r10; \
r1 += -512; \
r2 = 488; \
r3 = r10; \
r3 += -24; \
r4 = 0; \
r5 = 0; \
call %[bpf_dynptr_read]; \
r8 = 1; \
if r0 != 0 goto sjmp2; \
r8 = 0; \
sjmp2: \
r1 = r10; \
r1 += -24; \
r2 = 0; \
call %[bpf_ringbuf_discard_dynptr]; "
:
: __imm(bpf_map_update_elem),
__imm(bpf_map_lookup_elem),
__imm(bpf_ringbuf_reserve_dynptr),
__imm(bpf_ringbuf_discard_dynptr),
__imm(bpf_dynptr_from_mem),
__imm(bpf_dynptr_read),
__imm_addr(ringbuf),
__imm_addr(array_map4)
: __clobber_all
);
return 0;
}
/* Test that it is allowed to overwrite unreferenced dynptr. */
SEC("?raw_tp")
__success
int dynptr_overwrite_unref(void *ctx)
{
struct bpf_dynptr ptr;
if (get_map_val_dynptr(&ptr))
return 0;
if (get_map_val_dynptr(&ptr))
return 0;
if (get_map_val_dynptr(&ptr))
return 0;
return 0;
}
/* Test that slices are invalidated on reinitializing a dynptr. */
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int dynptr_invalidate_slice_reinit(void *ctx)
{
struct bpf_dynptr ptr;
__u8 *p;
if (get_map_val_dynptr(&ptr))
return 0;
p = bpf_dynptr_data(&ptr, 0, 1);
if (!p)
return 0;
if (get_map_val_dynptr(&ptr))
return 0;
/* this should fail */
return *p;
}
/* Invalidation of dynptr slices on destruction of dynptr should not miss
* mem_or_null pointers.
*/
SEC("?raw_tp")
__failure __msg("R{{[0-9]+}} type=scalar expected=percpu_ptr_")
int dynptr_invalidate_slice_or_null(void *ctx)
{
struct bpf_dynptr ptr;
__u8 *p;
if (get_map_val_dynptr(&ptr))
return 0;
p = bpf_dynptr_data(&ptr, 0, 1);
*(__u8 *)&ptr = 0;
/* this should fail */
bpf_this_cpu_ptr(p);
return 0;
}
/* Destruction of dynptr should also any slices obtained from it */
SEC("?raw_tp")
__failure __msg("R{{[0-9]+}} invalid mem access 'scalar'")
int dynptr_invalidate_slice_failure(void *ctx)
{
struct bpf_dynptr ptr1;
struct bpf_dynptr ptr2;
__u8 *p1, *p2;
if (get_map_val_dynptr(&ptr1))
return 0;
if (get_map_val_dynptr(&ptr2))
return 0;
p1 = bpf_dynptr_data(&ptr1, 0, 1);
if (!p1)
return 0;
p2 = bpf_dynptr_data(&ptr2, 0, 1);
if (!p2)
return 0;
*(__u8 *)&ptr1 = 0;
/* this should fail */
return *p1;
}
/* Invalidation of slices should be scoped and should not prevent dereferencing
* slices of another dynptr after destroying unrelated dynptr
*/
SEC("?raw_tp")
__success
int dynptr_invalidate_slice_success(void *ctx)
{
struct bpf_dynptr ptr1;
struct bpf_dynptr ptr2;
__u8 *p1, *p2;
if (get_map_val_dynptr(&ptr1))
return 1;
if (get_map_val_dynptr(&ptr2))
return 1;
p1 = bpf_dynptr_data(&ptr1, 0, 1);
if (!p1)
return 1;
p2 = bpf_dynptr_data(&ptr2, 0, 1);
if (!p2)
return 1;
*(__u8 *)&ptr1 = 0;
return *p2;
}
/* Overwriting referenced dynptr should be rejected */
SEC("?raw_tp")
__failure __msg("cannot overwrite referenced dynptr")
int dynptr_overwrite_ref(void *ctx)
{
struct bpf_dynptr ptr;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &ptr);
/* this should fail */
if (get_map_val_dynptr(&ptr))
bpf_ringbuf_discard_dynptr(&ptr, 0);
return 0;
}
/* Reject writes to dynptr slot from bpf_dynptr_read */
SEC("?raw_tp")
__failure __msg("potential write to dynptr at off=-16")
int dynptr_read_into_slot(void *ctx)
{
union {
struct {
char _pad[48];
struct bpf_dynptr ptr;
};
char buf[64];
} data;
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &data.ptr);
/* this should fail */
bpf_dynptr_read(data.buf, sizeof(data.buf), &data.ptr, 0, 0);
return 0;
}
/* bpf_dynptr_slice()s are read-only and cannot be written to */
SEC("?tc")
__failure __msg("R{{[0-9]+}} cannot write into rdonly_mem")
int skb_invalid_slice_write(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
/* this should fail */
hdr->h_proto = 1;
return SK_PASS;
}
/* The read-only data slice is invalidated whenever a helper changes packet data */
SEC("?tc")
__failure __msg("invalid mem access 'scalar'")
int skb_invalid_data_slice1(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
val = hdr->h_proto;
if (bpf_skb_pull_data(skb, skb->len))
return SK_DROP;
/* this should fail */
val = hdr->h_proto;
return SK_PASS;
}
/* The read-write data slice is invalidated whenever a helper changes packet data */
SEC("?tc")
__failure __msg("invalid mem access 'scalar'")
int skb_invalid_data_slice2(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
hdr->h_proto = 123;
if (bpf_skb_pull_data(skb, skb->len))
return SK_DROP;
/* this should fail */
hdr->h_proto = 1;
return SK_PASS;
}
/* The read-only data slice is invalidated whenever bpf_dynptr_write() is called */
SEC("?tc")
__failure __msg("invalid mem access 'scalar'")
int skb_invalid_data_slice3(struct __sk_buff *skb)
{
char write_data[64] = "hello there, world!!";
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
val = hdr->h_proto;
bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0);
/* this should fail */
val = hdr->h_proto;
return SK_PASS;
}
/* The read-write data slice is invalidated whenever bpf_dynptr_write() is called */
SEC("?tc")
__failure __msg("invalid mem access 'scalar'")
int skb_invalid_data_slice4(struct __sk_buff *skb)
{
char write_data[64] = "hello there, world!!";
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
hdr->h_proto = 123;
bpf_dynptr_write(&ptr, 0, write_data, sizeof(write_data), 0);
/* this should fail */
hdr->h_proto = 1;
return SK_PASS;
}
/* The read-only data slice is invalidated whenever a helper changes packet data */
SEC("?xdp")
__failure __msg("invalid mem access 'scalar'")
int xdp_invalid_data_slice1(struct xdp_md *xdp)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_xdp(xdp, 0, &ptr);
hdr = bpf_dynptr_slice(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
val = hdr->h_proto;
if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr)))
return XDP_DROP;
/* this should fail */
val = hdr->h_proto;
return XDP_PASS;
}
/* The read-write data slice is invalidated whenever a helper changes packet data */
SEC("?xdp")
__failure __msg("invalid mem access 'scalar'")
int xdp_invalid_data_slice2(struct xdp_md *xdp)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_xdp(xdp, 0, &ptr);
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
if (!hdr)
return SK_DROP;
hdr->h_proto = 9;
if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr)))
return XDP_DROP;
/* this should fail */
hdr->h_proto = 1;
return XDP_PASS;
}
/* Only supported prog type can create skb-type dynptrs */
SEC("?raw_tp")
__failure __msg("calling kernel function bpf_dynptr_from_skb is not allowed")
int skb_invalid_ctx(void *ctx)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_dynptr_from_skb(ctx, 0, &ptr);
return 0;
}
SEC("fentry/skb_tx_error")
__failure __msg("must be referenced or trusted")
int BPF_PROG(skb_invalid_ctx_fentry, void *skb)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_dynptr_from_skb(skb, 0, &ptr);
return 0;
}
SEC("fexit/skb_tx_error")
__failure __msg("must be referenced or trusted")
int BPF_PROG(skb_invalid_ctx_fexit, void *skb)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_dynptr_from_skb(skb, 0, &ptr);
return 0;
}
/* Reject writes to dynptr slot for uninit arg */
SEC("?raw_tp")
__failure __msg("potential write to dynptr at off=-16")
int uninit_write_into_slot(void *ctx)
{
struct {
char buf[64];
struct bpf_dynptr ptr;
} data;
bpf_ringbuf_reserve_dynptr(&ringbuf, 80, 0, &data.ptr);
/* this should fail */
bpf_get_current_comm(data.buf, 80);
return 0;
}
/* Only supported prog type can create xdp-type dynptrs */
SEC("?raw_tp")
__failure __msg("calling kernel function bpf_dynptr_from_xdp is not allowed")
int xdp_invalid_ctx(void *ctx)
{
struct bpf_dynptr ptr;
/* this should fail */
bpf_dynptr_from_xdp(ctx, 0, &ptr);
return 0;
}
__u32 hdr_size = sizeof(struct ethhdr);
/* Can't pass in variable-sized len to bpf_dynptr_slice */
SEC("?tc")
__failure __msg("unbounded memory access")
int dynptr_slice_var_len1(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
struct ethhdr *hdr;
char buffer[sizeof(*hdr)] = {};
bpf_dynptr_from_skb(skb, 0, &ptr);
/* this should fail */
hdr = bpf_dynptr_slice(&ptr, 0, buffer, hdr_size);
if (!hdr)
return SK_DROP;
return SK_PASS;
}
/* Can't pass in variable-sized len to bpf_dynptr_slice */
SEC("?tc")
__failure __msg("must be a known constant")
int dynptr_slice_var_len2(struct __sk_buff *skb)
{
char buffer[sizeof(struct ethhdr)] = {};
struct bpf_dynptr ptr;
struct ethhdr *hdr;
bpf_dynptr_from_skb(skb, 0, &ptr);
if (hdr_size <= sizeof(buffer)) {
/* this should fail */
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, hdr_size);
if (!hdr)
return SK_DROP;
hdr->h_proto = 12;
}
return SK_PASS;
}
static int callback(__u32 index, void *data)
{
*(__u32 *)data = 123;
return 0;
}
/* If the dynptr is written into in a callback function, its data
* slices should be invalidated as well.
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int invalid_data_slices(void *ctx)
{
struct bpf_dynptr ptr;
__u32 *slice;
if (get_map_val_dynptr(&ptr))
return 0;
slice = bpf_dynptr_data(&ptr, 0, sizeof(__u32));
if (!slice)
return 0;
bpf_loop(10, callback, &ptr, 0);
/* this should fail */
*slice = 1;
return 0;
}
/* Program types that don't allow writes to packet data should fail if
* bpf_dynptr_slice_rdwr is called
*/
SEC("cgroup_skb/ingress")
__failure __msg("the prog does not allow writes to packet data")
int invalid_slice_rdwr_rdonly(struct __sk_buff *skb)
{
char buffer[sizeof(struct ethhdr)] = {};
struct bpf_dynptr ptr;
struct ethhdr *hdr;
bpf_dynptr_from_skb(skb, 0, &ptr);
/* this should fail since cgroup_skb doesn't allow
* changing packet data
*/
hdr = bpf_dynptr_slice_rdwr(&ptr, 0, buffer, sizeof(buffer));
__sink(hdr);
return 0;
}
/* bpf_dynptr_adjust can only be called on initialized dynptrs */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #1")
int dynptr_adjust_invalid(void *ctx)
{
struct bpf_dynptr ptr = {};
/* this should fail */
bpf_dynptr_adjust(&ptr, 1, 2);
return 0;
}
/* bpf_dynptr_is_null can only be called on initialized dynptrs */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #1")
int dynptr_is_null_invalid(void *ctx)
{
struct bpf_dynptr ptr = {};
/* this should fail */
bpf_dynptr_is_null(&ptr);
return 0;
}
/* bpf_dynptr_is_rdonly can only be called on initialized dynptrs */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #1")
int dynptr_is_rdonly_invalid(void *ctx)
{
struct bpf_dynptr ptr = {};
/* this should fail */
bpf_dynptr_is_rdonly(&ptr);
return 0;
}
/* bpf_dynptr_size can only be called on initialized dynptrs */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #1")
int dynptr_size_invalid(void *ctx)
{
struct bpf_dynptr ptr = {};
/* this should fail */
bpf_dynptr_size(&ptr);
return 0;
}
/* Only initialized dynptrs can be cloned */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #1")
int clone_invalid1(void *ctx)
{
struct bpf_dynptr ptr1 = {};
struct bpf_dynptr ptr2;
/* this should fail */
bpf_dynptr_clone(&ptr1, &ptr2);
return 0;
}
/* Can't overwrite an existing dynptr when cloning */
SEC("?xdp")
__failure __msg("cannot overwrite referenced dynptr")
int clone_invalid2(struct xdp_md *xdp)
{
struct bpf_dynptr ptr1;
struct bpf_dynptr clone;
bpf_dynptr_from_xdp(xdp, 0, &ptr1);
bpf_ringbuf_reserve_dynptr(&ringbuf, 64, 0, &clone);
/* this should fail */
bpf_dynptr_clone(&ptr1, &clone);
bpf_ringbuf_submit_dynptr(&clone, 0);
return 0;
}
/* Invalidating a dynptr should invalidate its clones */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #3")
int clone_invalidate1(void *ctx)
{
struct bpf_dynptr clone;
struct bpf_dynptr ptr;
char read_data[64];
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone);
bpf_ringbuf_submit_dynptr(&ptr, 0);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), &clone, 0, 0);
return 0;
}
/* Invalidating a dynptr should invalidate its parent */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #3")
int clone_invalidate2(void *ctx)
{
struct bpf_dynptr ptr;
struct bpf_dynptr clone;
char read_data[64];
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone);
bpf_ringbuf_submit_dynptr(&clone, 0);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), &ptr, 0, 0);
return 0;
}
/* Invalidating a dynptr should invalidate its siblings */
SEC("?raw_tp")
__failure __msg("Expected an initialized dynptr as arg #3")
int clone_invalidate3(void *ctx)
{
struct bpf_dynptr ptr;
struct bpf_dynptr clone1;
struct bpf_dynptr clone2;
char read_data[64];
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone1);
bpf_dynptr_clone(&ptr, &clone2);
bpf_ringbuf_submit_dynptr(&clone2, 0);
/* this should fail */
bpf_dynptr_read(read_data, sizeof(read_data), &clone1, 0, 0);
return 0;
}
/* Invalidating a dynptr should invalidate any data slices
* of its clones
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int clone_invalidate4(void *ctx)
{
struct bpf_dynptr ptr;
struct bpf_dynptr clone;
int *data;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone);
data = bpf_dynptr_data(&clone, 0, sizeof(val));
if (!data)
return 0;
bpf_ringbuf_submit_dynptr(&ptr, 0);
/* this should fail */
*data = 123;
return 0;
}
/* Invalidating a dynptr should invalidate any data slices
* of its parent
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int clone_invalidate5(void *ctx)
{
struct bpf_dynptr ptr;
struct bpf_dynptr clone;
int *data;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
data = bpf_dynptr_data(&ptr, 0, sizeof(val));
if (!data)
return 0;
bpf_dynptr_clone(&ptr, &clone);
bpf_ringbuf_submit_dynptr(&clone, 0);
/* this should fail */
*data = 123;
return 0;
}
/* Invalidating a dynptr should invalidate any data slices
* of its sibling
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int clone_invalidate6(void *ctx)
{
struct bpf_dynptr ptr;
struct bpf_dynptr clone1;
struct bpf_dynptr clone2;
int *data;
bpf_ringbuf_reserve_dynptr(&ringbuf, val, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone1);
bpf_dynptr_clone(&ptr, &clone2);
data = bpf_dynptr_data(&clone1, 0, sizeof(val));
if (!data)
return 0;
bpf_ringbuf_submit_dynptr(&clone2, 0);
/* this should fail */
*data = 123;
return 0;
}
/* A skb clone's data slices should be invalid anytime packet data changes */
SEC("?tc")
__failure __msg("invalid mem access 'scalar'")
int clone_skb_packet_data(struct __sk_buff *skb)
{
char buffer[sizeof(__u32)] = {};
struct bpf_dynptr clone;
struct bpf_dynptr ptr;
__u32 *data;
bpf_dynptr_from_skb(skb, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone);
data = bpf_dynptr_slice_rdwr(&clone, 0, buffer, sizeof(buffer));
if (!data)
return XDP_DROP;
if (bpf_skb_pull_data(skb, skb->len))
return SK_DROP;
/* this should fail */
*data = 123;
return 0;
}
/* A xdp clone's data slices should be invalid anytime packet data changes */
SEC("?xdp")
__failure __msg("invalid mem access 'scalar'")
int clone_xdp_packet_data(struct xdp_md *xdp)
{
char buffer[sizeof(__u32)] = {};
struct bpf_dynptr clone;
struct bpf_dynptr ptr;
struct ethhdr *hdr;
__u32 *data;
bpf_dynptr_from_xdp(xdp, 0, &ptr);
bpf_dynptr_clone(&ptr, &clone);
data = bpf_dynptr_slice_rdwr(&clone, 0, buffer, sizeof(buffer));
if (!data)
return XDP_DROP;
if (bpf_xdp_adjust_head(xdp, 0 - (int)sizeof(*hdr)))
return XDP_DROP;
/* this should fail */
*data = 123;
return 0;
}
/* Buffers that are provided must be sufficiently long */
SEC("?cgroup_skb/egress")
__failure __msg("memory, len pair leads to invalid memory access")
int test_dynptr_skb_small_buff(struct __sk_buff *skb)
{
struct bpf_dynptr ptr;
char buffer[8] = {};
__u64 *data;
if (bpf_dynptr_from_skb(skb, 0, &ptr)) {
err = 1;
return 1;
}
/* This may return NULL. SKB may require a buffer */
data = bpf_dynptr_slice(&ptr, 0, buffer, 9);
return !!data;
}
__noinline long global_call_bpf_dynptr(const struct bpf_dynptr *dynptr)
{
long ret = 0;
/* Avoid leaving this global function empty to avoid having the compiler
* optimize away the call to this global function.
*/
__sink(ret);
return ret;
}
SEC("?raw_tp")
__failure __msg("arg#1 expected pointer to stack or const struct bpf_dynptr")
int test_dynptr_reg_type(void *ctx)
{
struct task_struct *current = NULL;
/* R1 should be holding a PTR_TO_BTF_ID, so this shouldn't be a
* reg->type that can be passed to a function accepting a
* ARG_PTR_TO_DYNPTR | MEM_RDONLY. process_dynptr_func() should catch
* this.
*/
global_call_bpf_dynptr((const struct bpf_dynptr *)current);
return 0;
}
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