https://github.com/torvalds/linux
Tip revision: c3b92c8787367a8bb53d57d9789b558f1295cc96 authored by Linus Torvalds on 24 October 2011, 07:10:05 UTC
Linux 3.1
Linux 3.1
Tip revision: c3b92c8
securebits.h
#ifndef _LINUX_SECUREBITS_H
#define _LINUX_SECUREBITS_H 1
/* Each securesetting is implemented using two bits. One bit specifies
whether the setting is on or off. The other bit specify whether the
setting is locked or not. A setting which is locked cannot be
changed from user-level. */
#define issecure_mask(X) (1 << (X))
#ifdef __KERNEL__
#define issecure(X) (issecure_mask(X) & current_cred_xxx(securebits))
#endif
#define SECUREBITS_DEFAULT 0x00000000
/* When set UID 0 has no special privileges. When unset, we support
inheritance of root-permissions and suid-root executable under
compatibility mode. We raise the effective and inheritable bitmasks
*of the executable file* if the effective uid of the new process is
0. If the real uid is 0, we raise the effective (legacy) bit of the
executable file. */
#define SECURE_NOROOT 0
#define SECURE_NOROOT_LOCKED 1 /* make bit-0 immutable */
#define SECBIT_NOROOT (issecure_mask(SECURE_NOROOT))
#define SECBIT_NOROOT_LOCKED (issecure_mask(SECURE_NOROOT_LOCKED))
/* When set, setuid to/from uid 0 does not trigger capability-"fixup".
When unset, to provide compatiblility with old programs relying on
set*uid to gain/lose privilege, transitions to/from uid 0 cause
capabilities to be gained/lost. */
#define SECURE_NO_SETUID_FIXUP 2
#define SECURE_NO_SETUID_FIXUP_LOCKED 3 /* make bit-2 immutable */
#define SECBIT_NO_SETUID_FIXUP (issecure_mask(SECURE_NO_SETUID_FIXUP))
#define SECBIT_NO_SETUID_FIXUP_LOCKED \
(issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED))
/* When set, a process can retain its capabilities even after
transitioning to a non-root user (the set-uid fixup suppressed by
bit 2). Bit-4 is cleared when a process calls exec(); setting both
bit 4 and 5 will create a barrier through exec that no exec()'d
child can use this feature again. */
#define SECURE_KEEP_CAPS 4
#define SECURE_KEEP_CAPS_LOCKED 5 /* make bit-4 immutable */
#define SECBIT_KEEP_CAPS (issecure_mask(SECURE_KEEP_CAPS))
#define SECBIT_KEEP_CAPS_LOCKED (issecure_mask(SECURE_KEEP_CAPS_LOCKED))
#define SECURE_ALL_BITS (issecure_mask(SECURE_NOROOT) | \
issecure_mask(SECURE_NO_SETUID_FIXUP) | \
issecure_mask(SECURE_KEEP_CAPS))
#define SECURE_ALL_LOCKS (SECURE_ALL_BITS << 1)
#endif /* !_LINUX_SECUREBITS_H */