// 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()));

  }