cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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test_log_fixup.c (1330B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
      3
      4#include <linux/bpf.h>
      5#include <bpf/bpf_helpers.h>
      6#include <bpf/bpf_core_read.h>
      7
      8struct task_struct___bad {
      9	int pid;
     10	int fake_field;
     11	void *fake_field_subprog;
     12} __attribute__((preserve_access_index));
     13
     14SEC("?raw_tp/sys_enter")
     15int bad_relo(const void *ctx)
     16{
     17	static struct task_struct___bad *t;
     18
     19	return bpf_core_field_size(t->fake_field);
     20}
     21
     22static __noinline int bad_subprog(void)
     23{
     24	static struct task_struct___bad *t;
     25
     26	/* ugliness below is a field offset relocation */
     27	return (void *)&t->fake_field_subprog - (void *)t;
     28}
     29
     30SEC("?raw_tp/sys_enter")
     31int bad_relo_subprog(const void *ctx)
     32{
     33	static struct task_struct___bad *t;
     34
     35	return bad_subprog() + bpf_core_field_size(t->pid);
     36}
     37
     38struct {
     39	__uint(type, BPF_MAP_TYPE_ARRAY);
     40	__uint(max_entries, 1);
     41	__type(key, int);
     42	__type(value, int);
     43} existing_map SEC(".maps");
     44
     45struct {
     46	__uint(type, BPF_MAP_TYPE_ARRAY);
     47	__uint(max_entries, 1);
     48	__type(key, int);
     49	__type(value, int);
     50} missing_map SEC(".maps");
     51
     52SEC("?raw_tp/sys_enter")
     53int use_missing_map(const void *ctx)
     54{
     55	int zero = 0, *value;
     56
     57	value = bpf_map_lookup_elem(&existing_map, &zero);
     58
     59	value = bpf_map_lookup_elem(&missing_map, &zero);
     60
     61	return value != NULL;
     62}
     63
     64char _license[] SEC("license") = "GPL";