kernel/uid16.c

   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 SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
  22 {
  23         return sys_chown(filename, low2highuid(user), low2highgid(group));
  24 }
  25
  26 SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
  27 {
  28         return sys_lchown(filename, low2highuid(user), low2highgid(group));
  29 }
  30
  31 SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
  32 {
  33         return sys_fchown(fd, low2highuid(user), low2highgid(group));
  34 }
  35
  36 SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
  37 {
  38         return sys_setregid(low2highgid(rgid), low2highgid(egid));
  39 }
  40
  41 SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
  42 {
  43         return sys_setgid(low2highgid(gid));
  44 }
  45
  46 SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
  47 {
  48         return sys_setreuid(low2highuid(ruid), low2highuid(euid));
  49 }
  50
  51 SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
  52 {
  53         return sys_setuid(low2highuid(uid));
  54 }
  55
  56 SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
  57 {
  58         return sys_setresuid(low2highuid(ruid), low2highuid(euid),
  59                                  low2highuid(suid));
  60 }
  61
  62 SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
  63 {
  64         const struct cred *cred = current_cred();
  65         int retval;
  66         old_uid_t ruid, euid, suid;
  67
  68         ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
  69         euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
  70         suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
  71
  72         if (!(retval   = put_user(ruid, ruidp)) &&
  73             !(retval   = put_user(euid, euidp)))
  74                 retval = put_user(suid, suidp);
  75
  76         return retval;
  77 }
  78
  79 SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
  80 {
  81         return sys_setresgid(low2highgid(rgid), low2highgid(egid),
  82                                  low2highgid(sgid));
  83 }
  84
  85
  86 SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
  87 {
  88         const struct cred *cred = current_cred();
  89         int retval;
  90         old_gid_t rgid, egid, sgid;
  91
  92         rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
  93         egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
  94         sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
  95
  96         if (!(retval   = put_user(rgid, rgidp)) &&
  97             !(retval   = put_user(egid, egidp)))
  98                 retval = put_user(sgid, sgidp);
  99
 100         return retval;
 101 }
 102
 103 SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
 104 {
 105         return sys_setfsuid(low2highuid(uid));
 106 }
 107
 108 SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
 109 {
 110         return sys_setfsgid(low2highgid(gid));
 111 }
 112
 113 static int groups16_to_user(old_gid_t __user *grouplist,
 114     struct group_info *group_info)
 115 {
 116         struct user_namespace *user_ns = current_user_ns();
 117         int i;
 118         old_gid_t group;
 119         kgid_t kgid;
 120
 121         for (i = 0; i < group_info->ngroups; i++) {
 122                 kgid = group_info->gid[i];
 123                 group = high2lowgid(from_kgid_munged(user_ns, kgid));
 124                 if (put_user(group, grouplist+i))
 125                         return -EFAULT;
 126         }
 127
 128         return 0;
 129 }
 130
 131 static int groups16_from_user(struct group_info *group_info,
 132     old_gid_t __user *grouplist)
 133 {
 134         struct user_namespace *user_ns = current_user_ns();
 135         int i;
 136         old_gid_t group;
 137         kgid_t kgid;
 138
 139         for (i = 0; i < group_info->ngroups; i++) {
 140                 if (get_user(group, grouplist+i))
 141                         return  -EFAULT;
 142
 143                 kgid = make_kgid(user_ns, low2highgid(group));
 144                 if (!gid_valid(kgid))
 145                         return -EINVAL;
 146
 147                 group_info->gid[i] = kgid;
 148         }
 149
 150         return 0;
 151 }
 152
 153 SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 154 {
 155         const struct cred *cred = current_cred();
 156         int i;
 157
 158         if (gidsetsize < 0)
 159                 return -EINVAL;
 160
 161         i = cred->group_info->ngroups;
 162         if (gidsetsize) {
 163                 if (i > gidsetsize) {
 164                         i = -EINVAL;
 165                         goto out;
 166                 }
 167                 if (groups16_to_user(grouplist, cred->group_info)) {
 168                         i = -EFAULT;
 169                         goto out;
 170                 }
 171         }
 172 out:
 173         return i;
 174 }
 175
 176 SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
 177 {
 178         struct group_info *group_info;
 179         int retval;
 180
 181         if (!may_setgroups())
 182                 return -EPERM;
 183         if ((unsigned)gidsetsize > NGROUPS_MAX)
 184                 return -EINVAL;
 185
 186         group_info = groups_alloc(gidsetsize);
 187         if (!group_info)
 188                 return -ENOMEM;
 189         retval = groups16_from_user(group_info, grouplist);
 190         if (retval) {
 191                 put_group_info(group_info);
 192                 return retval;
 193         }
 194
 195         retval = set_current_groups(group_info);
 196         put_group_info(group_info);
 197
 198         return retval;
 199 }
 200
 201 SYSCALL_DEFINE0(getuid16)
 202 {
 203         return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
 204 }
 205
 206 SYSCALL_DEFINE0(geteuid16)
 207 {
 208         return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
 209 }
 210
 211 SYSCALL_DEFINE0(getgid16)
 212 {
 213         return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
 214 }
 215
 216 SYSCALL_DEFINE0(getegid16)
 217 {
 218         return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
 219 }