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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
char _license[] SEC("license") = "GPL";
struct sample {
int pid;
int seq;
long value;
char comm[16];
};
struct {
__uint(type, BPF_MAP_TYPE_USER_RINGBUF);
__uint(max_entries, 4096);
} user_ringbuf SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_RINGBUF);
__uint(max_entries, 2);
} ringbuf SEC(".maps");
static int map_value;
static long
bad_access1(struct bpf_dynptr *dynptr, void *context)
{
const struct sample *sample;
sample = bpf_dynptr_data(dynptr - 1, 0, sizeof(*sample));
bpf_printk("Was able to pass bad pointer %lx\n", (__u64)dynptr - 1);
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to read before the pointer.
*/
SEC("?raw_tp")
__failure __msg("negative offset dynptr_ptr ptr")
int user_ringbuf_callback_bad_access1(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, bad_access1, NULL, 0);
return 0;
}
static long
bad_access2(struct bpf_dynptr *dynptr, void *context)
{
const struct sample *sample;
sample = bpf_dynptr_data(dynptr + 1, 0, sizeof(*sample));
bpf_printk("Was able to pass bad pointer %lx\n", (__u64)dynptr + 1);
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to read past the end of the pointer.
*/
SEC("?raw_tp")
__failure __msg("dereference of modified dynptr_ptr ptr")
int user_ringbuf_callback_bad_access2(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, bad_access2, NULL, 0);
return 0;
}
static long
write_forbidden(struct bpf_dynptr *dynptr, void *context)
{
*((long *)dynptr) = 0;
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to write to that pointer.
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'dynptr_ptr'")
int user_ringbuf_callback_write_forbidden(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, write_forbidden, NULL, 0);
return 0;
}
static long
null_context_write(struct bpf_dynptr *dynptr, void *context)
{
*((__u64 *)context) = 0;
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to write to that pointer.
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int user_ringbuf_callback_null_context_write(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, null_context_write, NULL, 0);
return 0;
}
static long
null_context_read(struct bpf_dynptr *dynptr, void *context)
{
__u64 id = *((__u64 *)context);
bpf_printk("Read id %lu\n", id);
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to write to that pointer.
*/
SEC("?raw_tp")
__failure __msg("invalid mem access 'scalar'")
int user_ringbuf_callback_null_context_read(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, null_context_read, NULL, 0);
return 0;
}
static long
try_discard_dynptr(struct bpf_dynptr *dynptr, void *context)
{
bpf_ringbuf_discard_dynptr(dynptr, 0);
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to read past the end of the pointer.
*/
SEC("?raw_tp")
__failure __msg("cannot release unowned const bpf_dynptr")
int user_ringbuf_callback_discard_dynptr(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, try_discard_dynptr, NULL, 0);
return 0;
}
static long
try_submit_dynptr(struct bpf_dynptr *dynptr, void *context)
{
bpf_ringbuf_submit_dynptr(dynptr, 0);
return 0;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to read past the end of the pointer.
*/
SEC("?raw_tp")
__failure __msg("cannot release unowned const bpf_dynptr")
int user_ringbuf_callback_submit_dynptr(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, try_submit_dynptr, NULL, 0);
return 0;
}
static long
invalid_drain_callback_return(struct bpf_dynptr *dynptr, void *context)
{
return 2;
}
/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
* not be able to write to that pointer.
*/
SEC("?raw_tp")
__failure __msg("At callback return the register R0 has ")
int user_ringbuf_callback_invalid_return(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, invalid_drain_callback_return, NULL, 0);
return 0;
}
static long
try_reinit_dynptr_mem(struct bpf_dynptr *dynptr, void *context)
{
bpf_dynptr_from_mem(&map_value, 4, 0, dynptr);
return 0;
}
static long
try_reinit_dynptr_ringbuf(struct bpf_dynptr *dynptr, void *context)
{
bpf_ringbuf_reserve_dynptr(&ringbuf, 8, 0, dynptr);
return 0;
}
SEC("?raw_tp")
__failure __msg("Dynptr has to be an uninitialized dynptr")
int user_ringbuf_callback_reinit_dynptr_mem(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, try_reinit_dynptr_mem, NULL, 0);
return 0;
}
SEC("?raw_tp")
__failure __msg("Dynptr has to be an uninitialized dynptr")
int user_ringbuf_callback_reinit_dynptr_ringbuf(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf, try_reinit_dynptr_ringbuf, NULL, 0);
return 0;
}
__noinline long global_call_bpf_dynptr_data(struct bpf_dynptr *dynptr)
{
bpf_dynptr_data(dynptr, 0xA, 0xA);
return 0;
}
static long callback_adjust_bpf_dynptr_reg_off(struct bpf_dynptr *dynptr,
void *ctx)
{
global_call_bpf_dynptr_data(dynptr += 1024);
return 0;
}
SEC("?raw_tp")
__failure __msg("dereference of modified dynptr_ptr ptr R1 off=16384 disallowed")
int user_ringbuf_callback_const_ptr_to_dynptr_reg_off(void *ctx)
{
bpf_user_ringbuf_drain(&user_ringbuf,
callback_adjust_bpf_dynptr_reg_off, NULL, 0);
return 0;
}
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