kernel/uid16.c

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