verifier_vfs_accept.c

  1// SPDX-License-Identifier: GPL-2.0
  2/* Copyright (c) 2024 Google LLC. */
  3
  4#include <vmlinux.h>
  5#include <errno.h>
  6#include <bpf/bpf_helpers.h>
  7#include <bpf/bpf_tracing.h>
  8
  9#include "bpf_misc.h"
 10#include "bpf_experimental.h"
 11
 12static char buf[64];
 13
 14SEC("lsm.s/file_open")
 15__success
 16int BPF_PROG(get_task_exe_file_and_put_kfunc_from_current_sleepable)
 17{
 18	struct file *acquired;
 19
 20	acquired = bpf_get_task_exe_file(bpf_get_current_task_btf());
 21	if (!acquired)
 22		return 0;
 23
 24	bpf_put_file(acquired);
 25	return 0;
 26}
 27
 28SEC("lsm/file_open")
 29__success
 30int BPF_PROG(get_task_exe_file_and_put_kfunc_from_current_non_sleepable, struct file *file)
 31{
 32	struct file *acquired;
 33
 34	acquired = bpf_get_task_exe_file(bpf_get_current_task_btf());
 35	if (!acquired)
 36		return 0;
 37
 38	bpf_put_file(acquired);
 39	return 0;
 40}
 41
 42SEC("lsm.s/task_alloc")
 43__success
 44int BPF_PROG(get_task_exe_file_and_put_kfunc_from_argument,
 45	     struct task_struct *task)
 46{
 47	struct file *acquired;
 48
 49	acquired = bpf_get_task_exe_file(task);
 50	if (!acquired)
 51		return 0;
 52
 53	bpf_put_file(acquired);
 54	return 0;
 55}
 56
 57SEC("lsm.s/inode_getattr")
 58__success
 59int BPF_PROG(path_d_path_from_path_argument, struct path *path)
 60{
 61	int ret;
 62
 63	ret = bpf_path_d_path(path, buf, sizeof(buf));
 64	__sink(ret);
 65	return 0;
 66}
 67
 68SEC("lsm.s/file_open")
 69__success
 70int BPF_PROG(path_d_path_from_file_argument, struct file *file)
 71{
 72	int ret;
 73	const struct path *path;
 74
 75	/* The f_path member is a path which is embedded directly within a
 76	 * file. Therefore, a pointer to such embedded members are still
 77	 * recognized by the BPF verifier as being PTR_TRUSTED as it's
 78	 * essentially PTR_TRUSTED w/ a non-zero fixed offset.
 79	 */
 80	path = &file->f_path;
 81	ret = bpf_path_d_path(path, buf, sizeof(buf));
 82	__sink(ret);
 83	return 0;
 84}
 85
 86SEC("lsm.s/inode_rename")
 87__success
 88int BPF_PROG(inode_rename, struct inode *old_dir, struct dentry *old_dentry,
 89	     struct inode *new_dir, struct dentry *new_dentry,
 90	     unsigned int flags)
 91{
 92	struct inode *inode = new_dentry->d_inode;
 93	ino_t ino;
 94
 95	if (!inode)
 96		return 0;
 97	ino = inode->i_ino;
 98	if (ino == 0)
 99		return -EACCES;
100	return 0;
101}
102
103char _license[] SEC("license") = "GPL";