root/include/uapi/linux/securebits.h

INCLUDED FROM

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _UAPI_LINUX_SECUREBITS_H
   3 #define _UAPI_LINUX_SECUREBITS_H
   4 
   5 /* Each securesetting is implemented using two bits. One bit specifies
   6    whether the setting is on or off. The other bit specify whether the
   7    setting is locked or not. A setting which is locked cannot be
   8    changed from user-level. */
   9 #define issecure_mask(X)        (1 << (X))
  10 
  11 #define SECUREBITS_DEFAULT 0x00000000
  12 
  13 /* When set UID 0 has no special privileges. When unset, we support
  14    inheritance of root-permissions and suid-root executable under
  15    compatibility mode. We raise the effective and inheritable bitmasks
  16    *of the executable file* if the effective uid of the new process is
  17    0. If the real uid is 0, we raise the effective (legacy) bit of the
  18    executable file. */
  19 #define SECURE_NOROOT                   0
  20 #define SECURE_NOROOT_LOCKED            1  /* make bit-0 immutable */
  21 
  22 #define SECBIT_NOROOT           (issecure_mask(SECURE_NOROOT))
  23 #define SECBIT_NOROOT_LOCKED    (issecure_mask(SECURE_NOROOT_LOCKED))
  24 
  25 /* When set, setuid to/from uid 0 does not trigger capability-"fixup".
  26    When unset, to provide compatiblility with old programs relying on
  27    set*uid to gain/lose privilege, transitions to/from uid 0 cause
  28    capabilities to be gained/lost. */
  29 #define SECURE_NO_SETUID_FIXUP          2
  30 #define SECURE_NO_SETUID_FIXUP_LOCKED   3  /* make bit-2 immutable */
  31 
  32 #define SECBIT_NO_SETUID_FIXUP  (issecure_mask(SECURE_NO_SETUID_FIXUP))
  33 #define SECBIT_NO_SETUID_FIXUP_LOCKED \
  34                         (issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED))
  35 
  36 /* When set, a process can retain its capabilities even after
  37    transitioning to a non-root user (the set-uid fixup suppressed by
  38    bit 2). Bit-4 is cleared when a process calls exec(); setting both
  39    bit 4 and 5 will create a barrier through exec that no exec()'d
  40    child can use this feature again. */
  41 #define SECURE_KEEP_CAPS                4
  42 #define SECURE_KEEP_CAPS_LOCKED         5  /* make bit-4 immutable */
  43 
  44 #define SECBIT_KEEP_CAPS        (issecure_mask(SECURE_KEEP_CAPS))
  45 #define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED))
  46 
  47 /* When set, a process cannot add new capabilities to its ambient set. */
  48 #define SECURE_NO_CAP_AMBIENT_RAISE             6
  49 #define SECURE_NO_CAP_AMBIENT_RAISE_LOCKED      7  /* make bit-6 immutable */
  50 
  51 #define SECBIT_NO_CAP_AMBIENT_RAISE (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
  52 #define SECBIT_NO_CAP_AMBIENT_RAISE_LOCKED \
  53                         (issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE_LOCKED))
  54 
  55 #define SECURE_ALL_BITS         (issecure_mask(SECURE_NOROOT) | \
  56                                  issecure_mask(SECURE_NO_SETUID_FIXUP) | \
  57                                  issecure_mask(SECURE_KEEP_CAPS) | \
  58                                  issecure_mask(SECURE_NO_CAP_AMBIENT_RAISE))
  59 #define SECURE_ALL_LOCKS        (SECURE_ALL_BITS << 1)
  60 
  61 #endif /* _UAPI_LINUX_SECUREBITS_H */