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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ima.c (1822B)

      1// SPDX-License-Identifier: GPL-2.0
      2
      3/*
      4 * Copyright 2020 Google LLC.
      5 */
      6
      7#include "vmlinux.h"
      8#include <errno.h>
      9#include <bpf/bpf_helpers.h>
     10#include <bpf/bpf_tracing.h>
     11
     12u32 monitored_pid = 0;
     13
     14struct {
     15	__uint(type, BPF_MAP_TYPE_RINGBUF);
     16	__uint(max_entries, 1 << 12);
     17} ringbuf SEC(".maps");
     18
     19char _license[] SEC("license") = "GPL";
     20
     21bool use_ima_file_hash;
     22bool enable_bprm_creds_for_exec;
     23bool enable_kernel_read_file;
     24bool test_deny;
     25
     26static void ima_test_common(struct file *file)
     27{
     28	u64 ima_hash = 0;
     29	u64 *sample;
     30	int ret;
     31	u32 pid;
     32
     33	pid = bpf_get_current_pid_tgid() >> 32;
     34	if (pid == monitored_pid) {
     35		if (!use_ima_file_hash)
     36			ret = bpf_ima_inode_hash(file->f_inode, &ima_hash,
     37						 sizeof(ima_hash));
     38		else
     39			ret = bpf_ima_file_hash(file, &ima_hash,
     40						sizeof(ima_hash));
     41		if (ret < 0 || ima_hash == 0)
     42			return;
     43
     44		sample = bpf_ringbuf_reserve(&ringbuf, sizeof(u64), 0);
     45		if (!sample)
     46			return;
     47
     48		*sample = ima_hash;
     49		bpf_ringbuf_submit(sample, 0);
     50	}
     51
     52	return;
     53}
     54
     55static int ima_test_deny(void)
     56{
     57	u32 pid;
     58
     59	pid = bpf_get_current_pid_tgid() >> 32;
     60	if (pid == monitored_pid && test_deny)
     61		return -EPERM;
     62
     63	return 0;
     64}
     65
     66SEC("lsm.s/bprm_committed_creds")
     67void BPF_PROG(bprm_committed_creds, struct linux_binprm *bprm)
     68{
     69	ima_test_common(bprm->file);
     70}
     71
     72SEC("lsm.s/bprm_creds_for_exec")
     73int BPF_PROG(bprm_creds_for_exec, struct linux_binprm *bprm)
     74{
     75	if (!enable_bprm_creds_for_exec)
     76		return 0;
     77
     78	ima_test_common(bprm->file);
     79	return 0;
     80}
     81
     82SEC("lsm.s/kernel_read_file")
     83int BPF_PROG(kernel_read_file, struct file *file, enum kernel_read_file_id id,
     84	     bool contents)
     85{
     86	int ret;
     87
     88	if (!enable_kernel_read_file)
     89		return 0;
     90
     91	if (!contents)
     92		return 0;
     93
     94	if (id != READING_POLICY)
     95		return 0;
     96
     97	ret = ima_test_deny();
     98	if (ret < 0)
     99		return ret;
    100
    101	ima_test_common(file);
    102	return 0;
    103}