62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <vmlinux.h>
|
|
#include <bpf/bpf_helpers.h>
|
|
|
|
#include "bpf_misc.h"
|
|
|
|
struct hmap_elem {
|
|
struct bpf_timer timer;
|
|
};
|
|
|
|
struct {
|
|
__uint(type, BPF_MAP_TYPE_HASH);
|
|
__uint(max_entries, 64);
|
|
__type(key, int);
|
|
__type(value, struct hmap_elem);
|
|
} hmap SEC(".maps");
|
|
|
|
__attribute__((noinline))
|
|
static int timer_cb(void *map, int *key, struct bpf_timer *timer)
|
|
{
|
|
volatile char buf[256] = {};
|
|
return buf[69];
|
|
}
|
|
|
|
__attribute__((noinline))
|
|
static int bad_timer_cb(void *map, int *key, struct bpf_timer *timer)
|
|
{
|
|
volatile char buf[300] = {};
|
|
return buf[255] + timer_cb(NULL, NULL, NULL);
|
|
}
|
|
|
|
SEC("tc")
|
|
__failure __msg("combined stack size of 2 calls is")
|
|
int pseudo_call_check(struct __sk_buff *ctx)
|
|
{
|
|
struct hmap_elem *elem;
|
|
volatile char buf[256] = {};
|
|
|
|
elem = bpf_map_lookup_elem(&hmap, &(int){0});
|
|
if (!elem)
|
|
return 0;
|
|
|
|
timer_cb(NULL, NULL, NULL);
|
|
return bpf_timer_set_callback(&elem->timer, timer_cb) + buf[0];
|
|
}
|
|
|
|
SEC("tc")
|
|
__failure __msg("combined stack size of 2 calls is")
|
|
int async_call_root_check(struct __sk_buff *ctx)
|
|
{
|
|
struct hmap_elem *elem;
|
|
volatile char buf[256] = {};
|
|
|
|
elem = bpf_map_lookup_elem(&hmap, &(int){0});
|
|
if (!elem)
|
|
return 0;
|
|
|
|
return bpf_timer_set_callback(&elem->timer, bad_timer_cb) + buf[0];
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|