include/linux/securebits.h

   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 effective (legacy) bit 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-"fixup".
  16    When unset, to provide compatiblility with old programs relying on
  17    set*uid to gain/lose privilege, transitions to/from uid 0 cause
  18    capabilities to be gained/lost. */
  19 #define SECURE_NO_SETUID_FIXUP          2
  20 #define SECURE_NO_SETUID_FIXUP_LOCKED   3  /* make bit-2 immutable */
  21
  22 /* When set, a process can retain its capabilities even after
  23    transitioning to a non-root user (the set-uid fixup suppressed by
  24    bit 2). Bit-4 is cleared when a process calls exec(); setting both
  25    bit 4 and 5 will create a barrier through exec that no exec()'d
  26    child can use this feature again. */
  27 #define SECURE_KEEP_CAPS                4
  28 #define SECURE_KEEP_CAPS_LOCKED         5  /* make bit-4 immutable */
  29
  30 /* Each securesetting is implemented using two bits. One bit specifies
  31    whether the setting is on or off. The other bit specify whether the
  32    setting is locked or not. A setting which is locked cannot be
  33    changed from user-level. */
  34 #define issecure_mask(X)        (1 << (X))
  35 #define issecure(X)             (issecure_mask(X) & current->securebits)
  36
  37 #define SECURE_ALL_BITS         (issecure_mask(SECURE_NOROOT) | \
  38                                  issecure_mask(SECURE_NO_SETUID_FIXUP) | \
  39                                  issecure_mask(SECURE_KEEP_CAPS))
  40 #define SECURE_ALL_LOCKS        (SECURE_ALL_BITS << 1)
  41
  42 #endif /* !_LINUX_SECUREBITS_H */