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