Quelle  uid16.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Wrapper functions for 16bit uid back compatibility. All nicely tied
 * together in the faint hope we can take the out in five years time.
 */

#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/prctl.h>
#include <linux/capability.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/syscalls.h>

#include <linux/uaccess.h>

#include "uid16.h"

SYSCALL_DEFINE3(chown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
 return ksys_chown(filename, low2highuid(user), low2highgid(group));
}

SYSCALL_DEFINE3(lchown16, const char __user *, filename, old_uid_t, user, old_gid_t, group)
{
 return ksys_lchown(filename, low2highuid(user), low2highgid(group));
}

SYSCALL_DEFINE3(fchown16, unsigned int, fd, old_uid_t, user, old_gid_t, group)
{
 return ksys_fchown(fd, low2highuid(user), low2highgid(group));
}

SYSCALL_DEFINE2(setregid16, old_gid_t, rgid, old_gid_t, egid)
{
 return __sys_setregid(low2highgid(rgid), low2highgid(egid));
}

SYSCALL_DEFINE1(setgid16, old_gid_t, gid)
{
 return __sys_setgid(low2highgid(gid));
}

SYSCALL_DEFINE2(setreuid16, old_uid_t, ruid, old_uid_t, euid)
{
 return __sys_setreuid(low2highuid(ruid), low2highuid(euid));
}

SYSCALL_DEFINE1(setuid16, old_uid_t, uid)
{
 return __sys_setuid(low2highuid(uid));
}

SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
{
 return __sys_setresuid(low2highuid(ruid), low2highuid(euid),
     low2highuid(suid));
}

SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
{
 const struct cred *cred = current_cred();
 int retval;
 old_uid_t ruid, euid, suid;

 ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
 euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
 suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));

 if (!(retval   = put_user(ruid, ruidp)) &&
     !(retval   = put_user(euid, euidp)))
  retval = put_user(suid, suidp);

 return retval;
}

SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
{
 return __sys_setresgid(low2highgid(rgid), low2highgid(egid),
     low2highgid(sgid));
}

SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
{
 const struct cred *cred = current_cred();
 int retval;
 old_gid_t rgid, egid, sgid;

 rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
 egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
 sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));

 if (!(retval   = put_user(rgid, rgidp)) &&
     !(retval   = put_user(egid, egidp)))
  retval = put_user(sgid, sgidp);

 return retval;
}

SYSCALL_DEFINE1(setfsuid16, old_uid_t, uid)
{
 return __sys_setfsuid(low2highuid(uid));
}

SYSCALL_DEFINE1(setfsgid16, old_gid_t, gid)
{
 return __sys_setfsgid(low2highgid(gid));
}

static int groups16_to_user(old_gid_t __user *grouplist,
    struct group_info *group_info)
{
 struct user_namespace *user_ns = current_user_ns();
 int i;
 old_gid_t group;
 kgid_t kgid;

 for (i = 0; i < group_info->ngroups; i++) {
  kgid = group_info->gid[i];
  group = high2lowgid(from_kgid_munged(user_ns, kgid));
  if (put_user(group, grouplist+i))
   return -EFAULT;
 }

 return 0;
}

static int groups16_from_user(struct group_info *group_info,
    old_gid_t __user *grouplist)
{
 struct user_namespace *user_ns = current_user_ns();
 int i;
 old_gid_t group;
 kgid_t kgid;

 for (i = 0; i < group_info->ngroups; i++) {
  if (get_user(group, grouplist+i))
   return  -EFAULT;

  kgid = make_kgid(user_ns, low2highgid(group));
  if (!gid_valid(kgid))
   return -EINVAL;

  group_info->gid[i] = kgid;
 }

 return 0;
}

SYSCALL_DEFINE2(getgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
 const struct cred *cred = current_cred();
 int i;

 if (gidsetsize < 0)
  return -EINVAL;

 i = cred->group_info->ngroups;
 if (gidsetsize) {
  if (i > gidsetsize) {
   i = -EINVAL;
   goto out;
  }
  if (groups16_to_user(grouplist, cred->group_info)) {
   i = -EFAULT;
   goto out;
  }
 }
out:
 return i;
}

SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
{
 struct group_info *group_info;
 int retval;

 if (!may_setgroups())
  return -EPERM;
 if ((unsigned)gidsetsize > NGROUPS_MAX)
  return -EINVAL;

 group_info = groups_alloc(gidsetsize);
 if (!group_info)
  return -ENOMEM;
 retval = groups16_from_user(group_info, grouplist);
 if (retval) {
  put_group_info(group_info);
  return retval;
 }

 groups_sort(group_info);
 retval = set_current_groups(group_info);
 put_group_info(group_info);

 return retval;
}

SYSCALL_DEFINE0(getuid16)
{
 return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
}

SYSCALL_DEFINE0(geteuid16)
{
 return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
}

SYSCALL_DEFINE0(getgid16)
{
 return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
}

SYSCALL_DEFINE0(getegid16)
{
 return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
}