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  */
39 struct 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 
48 bool 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 
96 int raw_openat2(int dfd, const char *path, void *how, size_t size);
97 int sys_openat2(int dfd, const char *path, struct open_how *how);
98 int sys_openat(int dfd, const char *path, struct open_how *how);
99 int sys_renameat2(int olddirfd, const char *oldpath,
100 		  int newdirfd, const char *newpath, unsigned int flags);
101 
102 int touchat(int dfd, const char *path);
103 char *fdreadlink(int fd);
104 bool fdequal(int fd, int dfd, const char *path);
105 
106 extern bool openat2_supported;
107 
108 #endif /* __RESOLVEAT_H__ */
109