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_d_path_check_rdonly_mem.c (717B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2022 Google */
      3
      4#include "vmlinux.h"
      5#include <bpf/bpf_helpers.h>
      6#include <bpf/bpf_tracing.h>
      7
      8extern const int bpf_prog_active __ksym;
      9
     10SEC("fentry/security_inode_getattr")
     11int BPF_PROG(d_path_check_rdonly_mem, struct path *path, struct kstat *stat,
     12	     __u32 request_mask, unsigned int query_flags)
     13{
     14	void *active;
     15	__u32 cpu;
     16
     17	cpu = bpf_get_smp_processor_id();
     18	active = (void *)bpf_per_cpu_ptr(&bpf_prog_active, cpu);
     19	if (active) {
     20		/* FAIL here! 'active' points to readonly memory. bpf helpers
     21		 * that update its arguments can not write into it.
     22		 */
     23		bpf_d_path(path, active, sizeof(int));
     24	}
     25	return 0;
     26}
     27
     28char _license[] SEC("license") = "GPL";