linux-headers (unknown)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 #ifndef _LINUX_SECUREBITS_H
3 #define _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 /* _LINUX_SECUREBITS_H */
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