linux/kernel/uid16.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 *      Wrapper functions for 16bit uid back compatibility. All nicely tied
   4 *      together in the faint hope we can take the out in five years time.
   5 */
   6
   7#include <linux/mm.h>
   8#include <linux/mman.h>
   9#include <linux/notifier.h>
  10#include <linux/reboot.h>
  11#include <linux/prctl.h>
  12#include <linux/capability.h>
  13#include <linux/init.h>
  14#include <linux/highuid.h>
  15#include <linux/security.h>
  16#include <linux/cred.h>
  17#include <linux/syscalls.h>
  18
  19#include <linux/uaccess.h>
  20
  21#include "uid16.h"
  22
  23SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
  24{
  25        return ksys_chown(filename, low2highuid(user), low2highgid(group));
  26}
  27
  28SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
  29{
  30        return ksys_lchown(filename, low2highuid(user), low2highgid(group));
  31}
  32
  33SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
  34{
  35        return ksys_fchown(fd, low2highuid(user), low2highgid(group));
  36}
  37
  38SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
  39{
  40        return __sys_setregid(low2highgid(rgid), low2highgid(egid));
  41}
  42
  43SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
  44{
  45        return __sys_setgid(low2highgid(gid));
  46}
  47
  48SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
  49{
  50        return __sys_setreuid(low2highuid(ruid), low2highuid(euid));
  51}
  52
  53SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
  54{
  55        return __sys_setuid(low2highuid(uid));
  56}
  57
  58SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
  59{
  60        return __sys_setresuid(low2highuid(ruid), low2highuid(euid),
  61                                 low2highuid(suid));
  62}
  63
  64SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
  65{
  66        const struct cred *cred = current_cred();
  67        int retval;
  68        old_uid_t ruid, euid, suid;
  69
  70        ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
  71        euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
  72        suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
  73
  74        if (!(retval   = put_user(ruid, ruidp)) &&
  75            !(retval   = put_user(euid, euidp)))
  76                retval = put_user(suid, suidp);
  77
  78        return retval;
  79}
  80
  81SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
  82{
  83        return __sys_setresgid(low2highgid(rgid), low2highgid(egid),
  84                                 low2highgid(sgid));
  85}
  86
  87SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
  88{
  89        const struct cred *cred = current_cred();
  90        int retval;
  91        old_gid_t rgid, egid, sgid;
  92
  93        rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
  94        egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
  95        sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
  96
  97        if (!(retval   = put_user(rgid, rgidp)) &&
  98            !(retval   = put_user(egid, egidp)))
  99                retval = put_user(sgid, sgidp);
 100
 101        return retval;
 102}
 103
 104SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
 105{
 106        return __sys_setfsuid(low2highuid(uid));
 107}
 108
 109SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
 110{
 111        return __sys_setfsgid(low2highgid(gid));
 112}
 113
 114static int groups16_to_user(old_gid_t __user *grouplist,
 115    struct group_info *group_info)
 116{
 117        struct user_namespace *user_ns = current_user_ns();
 118        int i;
 119        old_gid_t group;
 120        kgid_t kgid;
 121
 122        for (i = 0; i < group_info->ngroups; i++) {
 123                kgid = group_info->gid[i];
 124                group = high2lowgid(from_kgid_munged(user_ns, kgid));
 125                if (put_user(group, grouplist+i))
 126                        return -EFAULT;
 127        }
 128
 129        return 0;
 130}
 131
 132static int groups16_from_user(struct group_info *group_info,
 133    old_gid_t __user *grouplist)
 134{
 135        struct user_namespace *user_ns = current_user_ns();
 136        int i;
 137        old_gid_t group;
 138        kgid_t kgid;
 139
 140        for (i = 0; i < group_info->ngroups; i++) {
 141                if (get_user(group, grouplist+i))
 142                        return  -EFAULT;
 143
 144                kgid = make_kgid(user_ns, low2highgid(group));
 145                if (!gid_valid(kgid))
 146                        return -EINVAL;
 147
 148                group_info->gid[i] = kgid;
 149        }
 150
 151        return 0;
 152}
 153
 154SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 155{
 156        const struct cred *cred = current_cred();
 157        int i;
 158
 159        if (gidsetsize < 0)
 160                return -EINVAL;
 161
 162        i = cred->group_info->ngroups;
 163        if (gidsetsize) {
 164                if (i > gidsetsize) {
 165                        i = -EINVAL;
 166                        goto out;
 167                }
 168                if (groups16_to_user(grouplist, cred->group_info)) {
 169                        i = -EFAULT;
 170                        goto out;
 171                }
 172        }
 173out:
 174        return i;
 175}
 176
 177SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 178{
 179        struct group_info *group_info;
 180        int retval;
 181
 182        if (!may_setgroups())
 183                return -EPERM;
 184        if ((unsigned)gidsetsize > NGROUPS_MAX)
 185                return -EINVAL;
 186
 187        group_info = groups_alloc(gidsetsize);
 188        if (!group_info)
 189                return -ENOMEM;
 190        retval = groups16_from_user(group_info, grouplist);
 191        if (retval) {
 192                put_group_info(group_info);
 193                return retval;
 194        }
 195
 196        groups_sort(group_info);
 197        retval = set_current_groups(group_info);
 198        put_group_info(group_info);
 199
 200        return retval;
 201}
 202
 203SYSCALL_DEFINE0(getuid16)
 204{
 205        return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
 206}
 207
 208SYSCALL_DEFINE0(geteuid16)
 209{
 210        return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
 211}
 212
 213SYSCALL_DEFINE0(getgid16)
 214{
 215        return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
 216}
 217
 218SYSCALL_DEFINE0(getegid16)
 219{
 220        return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
 221}
 222