include/uapi/linux/securebits.h

   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 */