cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

highuid.h (3194B)

      1/* SPDX-License-Identifier: GPL-2.0 */
      2#ifndef _LINUX_HIGHUID_H
      3#define _LINUX_HIGHUID_H
      4
      5#include <linux/types.h>
      6
      7/*
      8 * general notes:
      9 *
     10 * CONFIG_UID16 is defined if the given architecture needs to
     11 * support backwards compatibility for old system calls.
     12 *
     13 * kernel code should use uid_t and gid_t at all times when dealing with
     14 * kernel-private data.
     15 *
     16 * old_uid_t and old_gid_t should only be different if CONFIG_UID16 is
     17 * defined, else the platform should provide dummy typedefs for them
     18 * such that they are equivalent to __kernel_{u,g}id_t.
     19 *
     20 * uid16_t and gid16_t are used on all architectures. (when dealing
     21 * with structures hard coded to 16 bits, such as in filesystems)
     22 */
     23
     24
     25/*
     26 * This is the "overflow" UID and GID. They are used to signify uid/gid
     27 * overflow to old programs when they request uid/gid information but are
     28 * using the old 16 bit interfaces.
     29 * When you run a libc5 program, it will think that all highuid files or
     30 * processes are owned by this uid/gid.
     31 * The idea is that it's better to do so than possibly return 0 in lieu of
     32 * 65536, etc.
     33 */
     34
     35extern int overflowuid;
     36extern int overflowgid;
     37
     38extern void __bad_uid(void);
     39extern void __bad_gid(void);
     40
     41#define DEFAULT_OVERFLOWUID	65534
     42#define DEFAULT_OVERFLOWGID	65534
     43
     44#ifdef CONFIG_UID16
     45
     46/* prevent uid mod 65536 effect by returning a default value for high UIDs */
     47#define high2lowuid(uid) ((uid) & ~0xFFFF ? (old_uid_t)overflowuid : (old_uid_t)(uid))
     48#define high2lowgid(gid) ((gid) & ~0xFFFF ? (old_gid_t)overflowgid : (old_gid_t)(gid))
     49/*
     50 * -1 is different in 16 bits than it is in 32 bits
     51 * these macros are used by chown(), setreuid(), ...,
     52 */
     53#define low2highuid(uid) ((uid) == (old_uid_t)-1 ? (uid_t)-1 : (uid_t)(uid))
     54#define low2highgid(gid) ((gid) == (old_gid_t)-1 ? (gid_t)-1 : (gid_t)(gid))
     55
     56#define __convert_uid(size, uid) \
     57	(size >= sizeof(uid) ? (uid) : high2lowuid(uid))
     58#define __convert_gid(size, gid) \
     59	(size >= sizeof(gid) ? (gid) : high2lowgid(gid))
     60	
     61
     62#else
     63
     64#define __convert_uid(size, uid) (uid)
     65#define __convert_gid(size, gid) (gid)
     66
     67#endif /* !CONFIG_UID16 */
     68
     69/* uid/gid input should be always 32bit uid_t */
     70#define SET_UID(var, uid) do { (var) = __convert_uid(sizeof(var), (uid)); } while (0)
     71#define SET_GID(var, gid) do { (var) = __convert_gid(sizeof(var), (gid)); } while (0)
     72
     73/*
     74 * Everything below this line is needed on all architectures, to deal with
     75 * filesystems that only store 16 bits of the UID/GID, etc.
     76 */
     77
     78/*
     79 * This is the UID and GID that will get written to disk if a filesystem
     80 * only supports 16-bit UIDs and the kernel has a high UID/GID to write
     81 */
     82extern int fs_overflowuid;
     83extern int fs_overflowgid;
     84
     85#define DEFAULT_FS_OVERFLOWUID	65534
     86#define DEFAULT_FS_OVERFLOWGID	65534
     87
     88/*
     89 * Since these macros are used in architectures that only need limited
     90 * 16-bit UID back compatibility, we won't use old_uid_t and old_gid_t
     91 */
     92#define fs_high2lowuid(uid) ((uid) & ~0xFFFF ? (uid16_t)fs_overflowuid : (uid16_t)(uid))
     93#define fs_high2lowgid(gid) ((gid) & ~0xFFFF ? (gid16_t)fs_overflowgid : (gid16_t)(gid))
     94
     95#define low_16_bits(x)	((x) & 0xFFFF)
     96#define high_16_bits(x)	(((x) & 0xFFFF0000) >> 16)
     97
     98#endif /* _LINUX_HIGHUID_H */