xref: /linux-6.15/include/linux/securebits.h (revision 3898b1b4)
1 #ifndef _LINUX_SECUREBITS_H
2 #define _LINUX_SECUREBITS_H 1
3 
4 #define SECUREBITS_DEFAULT 0x00000000
5 
6 /* When set UID 0 has no special privileges. When unset, we support
7    inheritance of root-permissions and suid-root executable under
8    compatibility mode. We raise the effective and inheritable bitmasks
9    *of the executable file* if the effective uid of the new process is
10    0. If the real uid is 0, we raise the inheritable bitmask of the
11    executable file. */
12 #define SECURE_NOROOT			0
13 #define SECURE_NOROOT_LOCKED		1  /* make bit-0 immutable */
14 
15 /* When set, setuid to/from uid 0 does not trigger capability-"fixes"
16    to be compatible with old programs relying on set*uid to loose
17    privileges. When unset, setuid doesn't change privileges. */
18 #define SECURE_NO_SETUID_FIXUP		2
19 #define SECURE_NO_SETUID_FIXUP_LOCKED	3  /* make bit-2 immutable */
20 
21 /* When set, a process can retain its capabilities even after
22    transitioning to a non-root user (the set-uid fixup suppressed by
23    bit 2). Bit-4 is cleared when a process calls exec(); setting both
24    bit 4 and 5 will create a barrier through exec that no exec()'d
25    child can use this feature again. */
26 #define SECURE_KEEP_CAPS		4
27 #define SECURE_KEEP_CAPS_LOCKED		5  /* make bit-4 immutable */
28 
29 /* Each securesetting is implemented using two bits. One bit specify
30    whether the setting is on or off. The other bit specify whether the
31    setting is fixed or not. A setting which is fixed cannot be changed
32    from user-level. */
33 #define issecure_mask(X)	(1 << (X))
34 #define issecure(X)		(issecure_mask(X) & current->securebits)
35 
36 #define SECURE_ALL_BITS		(issecure_mask(SECURE_NOROOT) | \
37 				 issecure_mask(SECURE_NO_SETUID_FIXUP) | \
38 				 issecure_mask(SECURE_KEEP_CAPS))
39 #define SECURE_ALL_LOCKS	(SECURE_ALL_BITS << 1)
40 
41 #endif /* !_LINUX_SECUREBITS_H */
42