1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _UAPI_LINUX_SECUREBITS_H
3#define _UAPI_LINUX_SECUREBITS_H
4
5/* Each securesetting is implemented using two bits. One bit specifies
6   whether the setting is on or off. The other bit specify whether the
7   setting is locked or not. A setting which is locked cannot be
8   changed from user-level. */
9#define issecure_mask(X)	(1 << (X))
10
11#define SECUREBITS_DEFAULT 0x00000000
12
13/* When set UID 0 has no special privileges. When unset, we support
14   inheritance of root-permissions and suid-root executable under
15   compatibility mode. We raise the effective and inheritable bitmasks
16   *of the executable file* if the effective uid of the new process is
17   0. If the real uid is 0, we raise the effective (legacy) bit of the
18   executable file. */
19#define SECURE_NOROOT			0
20#define SECURE_NOROOT_LOCKED		1  /* make bit-0 immutable */
21
22#define SECBIT_NOROOT		(issecure_mask(SECURE_NOROOT))
23#define SECBIT_NOROOT_LOCKED	(issecure_mask(SECURE_NOROOT_LOCKED))
24
25/* When set, setuid to/from uid 0 does not trigger capability-"fixup".
26   When unset, to provide compatiblility with old programs relying on
27   set*uid to gain/lose privilege, transitions to/from uid 0 cause
28   capabilities to be gained/lost. */
29#define SECURE_NO_SETUID_FIXUP		2
30#define SECURE_NO_SETUID_FIXUP_LOCKED	3  /* make bit-2 immutable */
31
32#define SECBIT_NO_SETUID_FIXUP	(issecure_mask(SECURE_NO_SETUID_FIXUP))
33#define SECBIT_NO_SETUID_FIXUP_LOCKED \
34			(issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED))
35
36/* When set, a process can retain its capabilities even after
37   transitioning to a non-root user (the set-uid fixup suppressed by
38   bit 2). Bit-4 is cleared when a process calls exec(); setting both
39   bit 4 and 5 will create a barrier through exec that no exec()'d
40   child can use this feature again. */
41#define SECURE_KEEP_CAPS		4
42#define SECURE_KEEP_CAPS_LOCKED		5  /* make bit-4 immutable */
43
44#define SECBIT_KEEP_CAPS	(issecure_mask(SECURE_KEEP_CAPS))
45#define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED))
46
47/* When set, a process cannot add new capabilities to its ambient set. */
48#define SECURE_NO_CAP_AMBIENT_RAISE		6
49#define SECURE_NO_CAP_AMBIENT_RAISE_LOCKED	7  /* make bit-6 immutable */
50
51#define SECBIT_NO_CAP_AMBIENT_RAISE (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
52#define SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED \
53			(issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED))
54
55#define SECURE_ALL_BITS		(issecure_mask(SECURE_NOROOT) | \
56				 issecure_mask(SECURE_NO_SETUID_FIXUP) | \
57				 issecure_mask(SECURE_KEEP_CAPS) | \
58				 issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
59#define SECURE_ALL_LOCKS	(SECURE_ALL_BITS << 1)
60
61#endif /* _UAPI_LINUX_SECUREBITS_H */
62