1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Author: Aleksa Sarai <cyphar@cyphar.com>
4 * Copyright (C) 2018-2019 SUSE LLC.
5 */
6
7#ifndef __RESOLVEAT_H__
8#define __RESOLVEAT_H__
9
10#define _GNU_SOURCE
11#include <stdint.h>
12#include <stdbool.h>
13#include <errno.h>
14#include <linux/types.h>
15#include "../kselftest.h"
16
17#define ARRAY_LEN(X) (sizeof (X) / sizeof (*(X)))
18#define BUILD_BUG_ON(e) ((void)(sizeof(struct { int:(-!!(e)); })))
19
20#ifndef SYS_openat2
21#ifndef __NR_openat2
22#define __NR_openat2 437
23#endif /* __NR_openat2 */
24#define SYS_openat2 __NR_openat2
25#endif /* SYS_openat2 */
26
27/*
28 * Arguments for how openat2(2) should open the target path. If @resolve is
29 * zero, then openat2(2) operates very similarly to openat(2).
30 *
31 * However, unlike openat(2), unknown bits in @flags result in -EINVAL rather
32 * than being silently ignored. @mode must be zero unless one of {O_CREAT,
33 * O_TMPFILE} are set.
34 *
35 * @flags: O_* flags.
36 * @mode: O_CREAT/O_TMPFILE file mode.
37 * @resolve: RESOLVE_* flags.
38 */
39struct open_how {
40	__u64 flags;
41	__u64 mode;
42	__u64 resolve;
43};
44
45#define OPEN_HOW_SIZE_VER0	24 /* sizeof first published struct */
46#define OPEN_HOW_SIZE_LATEST	OPEN_HOW_SIZE_VER0
47
48bool needs_openat2(const struct open_how *how);
49
50#ifndef RESOLVE_IN_ROOT
51/* how->resolve flags for openat2(2). */
52#define RESOLVE_NO_XDEV		0x01 /* Block mount-point crossings
53					(includes bind-mounts). */
54#define RESOLVE_NO_MAGICLINKS	0x02 /* Block traversal through procfs-style
55					"magic-links". */
56#define RESOLVE_NO_SYMLINKS	0x04 /* Block traversal through all symlinks
57					(implies OEXT_NO_MAGICLINKS) */
58#define RESOLVE_BENEATH		0x08 /* Block "lexical" trickery like
59					"..", symlinks, and absolute
60					paths which escape the dirfd. */
61#define RESOLVE_IN_ROOT		0x10 /* Make all jumps to "/" and ".."
62					be scoped inside the dirfd
63					(similar to chroot(2)). */
64#endif /* RESOLVE_IN_ROOT */
65
66#define E_func(func, ...)						      \
67	do {								      \
68		errno = 0;						      \
69		if (func(__VA_ARGS__) < 0)				      \
70			ksft_exit_fail_msg("%s:%d %s failed - errno:%d\n",    \
71					   __FILE__, __LINE__, #func, errno); \
72	} while (0)
73
74#define E_asprintf(...)		E_func(asprintf,	__VA_ARGS__)
75#define E_chmod(...)		E_func(chmod,		__VA_ARGS__)
76#define E_dup2(...)		E_func(dup2,		__VA_ARGS__)
77#define E_fchdir(...)		E_func(fchdir,		__VA_ARGS__)
78#define E_fstatat(...)		E_func(fstatat,		__VA_ARGS__)
79#define E_kill(...)		E_func(kill,		__VA_ARGS__)
80#define E_mkdirat(...)		E_func(mkdirat,		__VA_ARGS__)
81#define E_mount(...)		E_func(mount,		__VA_ARGS__)
82#define E_prctl(...)		E_func(prctl,		__VA_ARGS__)
83#define E_readlink(...)		E_func(readlink,	__VA_ARGS__)
84#define E_setresuid(...)	E_func(setresuid,	__VA_ARGS__)
85#define E_symlinkat(...)	E_func(symlinkat,	__VA_ARGS__)
86#define E_touchat(...)		E_func(touchat,		__VA_ARGS__)
87#define E_unshare(...)		E_func(unshare,		__VA_ARGS__)
88
89#define E_assert(expr, msg, ...)					\
90	do {								\
91		if (!(expr))						\
92			ksft_exit_fail_msg("ASSERT(%s:%d) failed (%s): " msg "\n", \
93					   __FILE__, __LINE__, #expr, ##__VA_ARGS__); \
94	} while (0)
95
96int raw_openat2(int dfd, const char *path, void *how, size_t size);
97int sys_openat2(int dfd, const char *path, struct open_how *how);
98int sys_openat(int dfd, const char *path, struct open_how *how);
99int sys_renameat2(int olddirfd, const char *oldpath,
100		  int newdirfd, const char *newpath, unsigned int flags);
101
102int touchat(int dfd, const char *path);
103char *fdreadlink(int fd);
104bool fdequal(int fd, int dfd, const char *path);
105
106extern bool openat2_supported;
107
108#endif /* __RESOLVEAT_H__ */
109