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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load_bytes_relative.c (1003B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2
      3/*
      4 * Copyright 2020 Google LLC.
      5 */
      6
      7#include <errno.h>
      8#include <linux/bpf.h>
      9#include <linux/if_ether.h>
     10#include <linux/ip.h>
     11#include <bpf/bpf_helpers.h>
     12
     13struct {
     14	__uint(type, BPF_MAP_TYPE_ARRAY);
     15	__uint(max_entries, 1);
     16	__type(key, __u32);
     17	__type(value, __u32);
     18} test_result SEC(".maps");
     19
     20SEC("cgroup_skb/egress")
     21int load_bytes_relative(struct __sk_buff *skb)
     22{
     23	struct ethhdr eth;
     24	struct iphdr iph;
     25
     26	__u32 map_key = 0;
     27	__u32 test_passed = 0;
     28
     29	/* MAC header is not set by the time cgroup_skb/egress triggers */
     30	if (bpf_skb_load_bytes_relative(skb, 0, &eth, sizeof(eth),
     31					BPF_HDR_START_MAC) != -EFAULT)
     32		goto fail;
     33
     34	if (bpf_skb_load_bytes_relative(skb, 0, &iph, sizeof(iph),
     35					BPF_HDR_START_NET))
     36		goto fail;
     37
     38	if (bpf_skb_load_bytes_relative(skb, 0xffff, &iph, sizeof(iph),
     39					BPF_HDR_START_NET) != -EFAULT)
     40		goto fail;
     41
     42	test_passed = 1;
     43
     44fail:
     45	bpf_map_update_elem(&test_result, &map_key, &test_passed, BPF_ANY);
     46
     47	return 1;
     48}