src/basic/securebits.h

   1 #pragma once
   2
   3 /* This is minimal version of Linux' linux/securebits.h header file,
   4  * which is licensed GPL2 */
   5
   6 #define SECUREBITS_DEFAULT 0x00000000
   7
   8 /* When set UID 0 has no special privileges. When unset, we support
   9    inheritance of root-permissions and suid-root executable under
  10    compatibility mode. We raise the effective and inheritable bitmasks
  11    *of the executable file* if the effective uid of the new process is
  12    0. If the real uid is 0, we raise the effective (legacy) bit of the
  13    executable file. */
  14 #define SECURE_NOROOT                   0
  15 #define SECURE_NOROOT_LOCKED            1  /* make bit-0 immutable */
  16
  17 /* When set, setuid to/from uid 0 does not trigger capability-"fixup".
  18    When unset, to provide compatibility with old programs relying on
  19    set*uid to gain/lose privilege, transitions to/from uid 0 cause
  20    capabilities to be gained/lost. */
  21 #define SECURE_NO_SETUID_FIXUP          2
  22 #define SECURE_NO_SETUID_FIXUP_LOCKED   3  /* make bit-2 immutable */
  23
  24 /* When set, a process can retain its capabilities even after
  25    transitioning to a non-root user (the set-uid fixup suppressed by
  26    bit 2). Bit-4 is cleared when a process calls exec(); setting both
  27    bit 4 and 5 will create a barrier through exec that no exec()'d
  28    child can use this feature again. */
  29 #define SECURE_KEEP_CAPS                4
  30 #define SECURE_KEEP_CAPS_LOCKED         5  /* make bit-4 immutable */
  31
  32 /* Each securesetting is implemented using two bits. One bit specifies
  33    whether the setting is on or off. The other bit specify whether the
  34    setting is locked or not. A setting which is locked cannot be
  35    changed from user-level. */
  36 #define issecure_mask(X)        (1 << (X))
  37 #define issecure(X)             (issecure_mask(X) & current_cred_xxx(securebits))
  38
  39 #define SECURE_ALL_BITS         (issecure_mask(SECURE_NOROOT) | \
  40                                  issecure_mask(SECURE_NO_SETUID_FIXUP) | \
  41                                  issecure_mask(SECURE_KEEP_CAPS))
  42 #define SECURE_ALL_LOCKS        (SECURE_ALL_BITS << 1)