newlib/winsup/cygwin/grp.cc

/* grp.cc

   Copyright 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   2008, 2009, 2011, 2012, 2013, 2014, 2015 Red Hat, Inc.

   Original stubs by Jason Molenda of Cygnus Support, crash@cygnus.com
   First implementation by Gunther Ebert, gunther.ebert@ixos-leipzig.de

This file is part of Cygwin.

This software is a copyrighted work licensed under the terms of the
Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
details. */

#include "winsup.h"
#include <lm.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include "cygerrno.h"
#include "pinfo.h"
#include "path.h"
#include "fhandler.h"
#include "dtable.h"
#include "cygheap.h"
#include "ntdll.h"
#include "miscfuncs.h"
#include "ldap.h"
#include "tls_pbuf.h"

static char * NO_COPY_RO null_ptr;

bool
pwdgrp::parse_group ()
{
  pg_grp &grp = group ()[curr_lines];
  grp.g.gr_name = next_str (':');
  if (!*grp.g.gr_name)
    return false;
  grp.g.gr_passwd = next_str (':');
  /* Note that lptr points to the first byte of the gr_gid field.
     We deliberately ignore the gr_gid and gr_mem entries when copying
     the buffer content since they are not referenced anymore. */
  grp.len = lptr - grp.g.gr_name;
  if (!next_num (grp.g.gr_gid))
    return false;
  /* Don't generate gr_mem entries. */
  grp.g.gr_mem = &null_ptr;
  grp.sid.getfromgr (&grp.g);
  return true;
}

muto NO_COPY pwdgrp::pglock;

void
pwdgrp::init_grp ()
{
  pwdgrp_buf_elem_size = sizeof (pg_grp);
  parse = &pwdgrp::parse_group;
}

struct group *
pwdgrp::find_group (cygpsid &sid)
{
  for (ULONG i = 0; i < curr_lines; i++)
    if (sid == group ()[i].sid)
      return &group ()[i].g;
  return NULL;
}

struct group *
pwdgrp::find_group (const char *name)
{
  for (ULONG i = 0; i < curr_lines; i++)
    if (strcasematch (group ()[i].g.gr_name, name))
      return &group ()[i].g;
  return NULL;
}

struct group *
pwdgrp::find_group (gid_t gid)
{
  for (ULONG i = 0; i < curr_lines; i++)
    if (gid == group ()[i].g.gr_gid)
      return &group ()[i].g;
  return NULL;
}

struct group *
internal_getgrsid (cygpsid &sid, cyg_ldap *pldap)
{
  struct group *ret;

  cygheap->pg.nss_init ();
  /* Check caches first. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.find_group (sid)))
    return ret;
  if (cygheap->pg.nss_grp_files ()
      && (ret = cygheap->pg.grp_cache.file.find_group (sid)))
    return ret;
  if (cygheap->pg.nss_grp_db ()
      && (ret = cygheap->pg.grp_cache.win.find_group (sid)))
    return ret;
  /* Ask sources afterwards. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.add_group_from_cygserver (sid)))
    return ret;
  if (cygheap->pg.nss_grp_files ())
    {
      cygheap->pg.grp_cache.file.check_file ();
      if ((ret = cygheap->pg.grp_cache.file.add_group_from_file (sid)))
	return ret;
    }
  if (cygheap->pg.nss_grp_db ())
    return cygheap->pg.grp_cache.win.add_group_from_windows (sid, pldap);
  return NULL;
}

/* This function gets only called from mkgroup via cygwin_internal. */
struct group *
internal_getgrsid_from_db (cygpsid &sid)
{
  cygheap->pg.nss_init ();
  return cygheap->pg.grp_cache.win.add_group_from_windows (sid);
}

struct group *
internal_getgrnam (const char *name, cyg_ldap *pldap)
{
  struct group *ret;

  cygheap->pg.nss_init ();
  /* Check caches first. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.find_group (name)))
    return ret;
  if (cygheap->pg.nss_grp_files ()
      && (ret = cygheap->pg.grp_cache.file.find_group (name)))
    return ret;
  if (cygheap->pg.nss_grp_db ()
      && (ret = cygheap->pg.grp_cache.win.find_group (name)))
    return ret;
  /* Ask sources afterwards. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.add_group_from_cygserver (name)))
    return ret;
  if (cygheap->pg.nss_grp_files ())
    {
      cygheap->pg.grp_cache.file.check_file ();
      if ((ret = cygheap->pg.grp_cache.file.add_group_from_file (name)))
	return ret;
    }
  if (cygheap->pg.nss_grp_db ())
    return cygheap->pg.grp_cache.win.add_group_from_windows (name, pldap);
  return NULL;
}

struct group *
internal_getgrgid (gid_t gid, cyg_ldap *pldap)
{
  struct group *ret;

  cygheap->pg.nss_init ();
  /* Check caches first. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.find_group (gid)))
    return ret;
  if (cygheap->pg.nss_grp_files ()
      && (ret = cygheap->pg.grp_cache.file.find_group (gid)))
    return ret;
  if (cygheap->pg.nss_grp_db ()
      && (ret = cygheap->pg.grp_cache.win.find_group (gid)))
    return ret;
  /* Ask sources afterwards. */
  if (cygheap->pg.nss_cygserver_caching ()
      && (ret = cygheap->pg.grp_cache.cygserver.add_group_from_cygserver (gid)))
    return ret;
  if (cygheap->pg.nss_grp_files ())
    {
      cygheap->pg.grp_cache.file.check_file ();
      if ((ret = cygheap->pg.grp_cache.file.add_group_from_file (gid)))
	return ret;
    }
  if (cygheap->pg.nss_grp_db () || gid == ILLEGAL_GID)
    return cygheap->pg.grp_cache.win.add_group_from_windows (gid, pldap);
  return NULL;
}

#ifndef __x86_64__
static struct __group16 *
grp32togrp16 (struct __group16 *gp16, struct group *gp32)
{
  if (!gp16 || !gp32)
    return NULL;

  /* Copying the pointers is actually unnecessary.  Just having the correct
     return type is important. */
  gp16->gr_name = gp32->gr_name;
  gp16->gr_passwd = gp32->gr_passwd;
  gp16->gr_gid = (__gid16_t) gp32->gr_gid;		/* Not loss-free */
  gp16->gr_mem = gp32->gr_mem;

  return gp16;
}
#endif

extern "C" int
getgrgid_r (gid_t gid, struct group *grp, char *buffer, size_t bufsize,
	    struct group **result)
{
  *result = NULL;

  if (!grp || !buffer)
    return ERANGE;

  struct group *tempgr = internal_getgrgid (gid);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* Check needed buffer size.  Deliberately ignore gr_mem. */
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* Make a copy of tempgr.  Deliberately ignore gr_mem. */
  *result = grp;
  grp->gr_gid = tempgr->gr_gid;
  buffer = stpcpy (grp->gr_name = buffer, tempgr->gr_name);
  buffer = stpcpy (grp->gr_passwd = buffer + 1, tempgr->gr_passwd);
  grp->gr_mem = (char **) (buffer + 1);
  grp->gr_mem[0] = NULL;
  return 0;
}

/* getgrgid/getgrnam are not reentrant. */
static struct {
  struct group g;
  char *buf;
  size_t bufsiz;
} app_gr;

static struct group *
getgr_cp (struct group *tempgr)
{
  if (!tempgr)
    return NULL;
  pg_grp *gr = (pg_grp *) tempgr;
  if (app_gr.bufsiz < gr->len)
    {
      char *newbuf = (char *) realloc (app_gr.buf, gr->len);
      if (!newbuf)
        {
          set_errno (ENOMEM);
          return NULL;
        }
      app_gr.buf = newbuf;
      app_gr.bufsiz = gr->len;
    }
  memcpy (app_gr.buf, gr->g.gr_name, gr->len);
  memcpy (&app_gr.g, &gr->g, sizeof gr->g);
  ptrdiff_t diff = app_gr.buf - gr->g.gr_name;
  app_gr.g.gr_name += diff;
  app_gr.g.gr_passwd += diff;
  return &app_gr.g;
}

extern "C" struct group *
getgrgid32 (gid_t gid)
{
  struct group *tempgr = internal_getgrgid (gid);
  pthread_testcancel ();
  return getgr_cp (tempgr);
}

#ifdef __x86_64__
EXPORT_ALIAS (getgrgid32, getgrgid)
#else
extern "C" struct __group16 *
getgrgid (__gid16_t gid)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrgid32 (gid16togid32 (gid)));
}
#endif

extern "C" int
getgrnam_r (const char *nam, struct group *grp, char *buffer,
	    size_t bufsize, struct group **result)
{
  *result = NULL;

  if (!grp || !buffer)
    return ERANGE;

  struct group *tempgr = internal_getgrnam (nam);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* Check needed buffer size.  Deliberately ignore gr_mem. */
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* Make a copy of tempgr.  Deliberately ignore gr_mem. */
  *result = grp;
  grp->gr_gid = tempgr->gr_gid;
  buffer = stpcpy (grp->gr_name = buffer, tempgr->gr_name);
  buffer = stpcpy (grp->gr_passwd = buffer + 1, tempgr->gr_passwd);
  grp->gr_mem = (char **) (buffer + 1);
  grp->gr_mem[0] = NULL;
  return 0;
}

extern "C" struct group *
getgrnam32 (const char *name)
{
  struct group *tempgr = internal_getgrnam (name);
  pthread_testcancel ();
  return getgr_cp (tempgr);
}

#ifdef __x86_64__
EXPORT_ALIAS (getgrnam32, getgrnam)
#else
extern "C" struct __group16 *
getgrnam (const char *name)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrnam32 (name));
}
#endif

/* getgrent functions are not reentrant. */
static gr_ent grent;

void *
gr_ent::enumerate_caches ()
{
  switch (max)
    {
    case 0:
      if (cygheap->pg.nss_cygserver_caching ())
	{
	  pwdgrp &grc = cygheap->pg.grp_cache.cygserver;
	  if (cnt < grc.cached_groups ())
	    return &grc.group ()[cnt++].g;
	}
      cnt = 0;
      max = 1;
      /*FALLTHRU*/
    case 1:
      if (from_files)
	{
	  pwdgrp &grf = cygheap->pg.grp_cache.file;
	  grf.check_file ();
	  if (cnt < grf.cached_groups ())
	    return &grf.group ()[cnt++].g;
	}
      cnt = 0;
      max = 2;
      /*FALLTHRU*/
    case 2:
      if (from_db)
	{
	  pwdgrp &grw = cygheap->pg.grp_cache.win;
	  if (cnt < grw.cached_groups ())
	    return &grw.group ()[cnt++].g;
	}
      break;
    }
  cnt = max = 0;
  return NULL;
}

void *
gr_ent::enumerate_local ()
{
  while (true)
    {
      if (!cnt)
	{
	  DWORD total;
	  NET_API_STATUS ret;

	  if (buf)
	    {
	      NetApiBufferFree (buf);
	      buf = NULL;
	    }
	  if (resume == ULONG_MAX)
	    ret = ERROR_NO_MORE_ITEMS;
	  else
	    ret = NetLocalGroupEnum (NULL, 0, (PBYTE *) &buf,
				     MAX_PREFERRED_LENGTH,
				     &max, &total, &resume);
	  if (ret == NERR_Success)
	    resume = ULONG_MAX;
	  else if (ret != ERROR_MORE_DATA)
	    {
	      cnt = max = resume = 0;
	      return NULL;
	    }
	}
      while (cnt < max)
	{
	  cygsid sid;
	  DWORD slen = SECURITY_MAX_SID_SIZE;
	  WCHAR dom[DNLEN + 1];
	  DWORD dlen = DNLEN + 1;
	  SID_NAME_USE acc_type;

	  LookupAccountNameW (NULL,
			      ((PLOCALGROUP_INFO_0) buf)[cnt++].lgrpi0_name,
			      sid, &slen, dom, &dlen, &acc_type);
	  fetch_user_arg_t arg;
	  arg.type = SID_arg;
	  arg.sid = &sid;
	  char *line = pg.fetch_account_from_windows (arg);
	  if (line)
	    return pg.add_account_post_fetch (line, false);
	}
      cnt = 0;
    }
}

struct group *
gr_ent::getgrent (void)
{
  if (state == rewound)
    setent (true);
  else
    clear_cache ();
  return (struct group *) getent ();
}

extern "C" void
setgrent ()
{
  grent.setgrent ();
}

extern "C" struct group *
getgrent32 (void)
{
  return grent.getgrent ();
}

#ifdef __x86_64__
EXPORT_ALIAS (getgrent32, getgrent)
#else
extern "C" struct __group16 *
getgrent ()
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

  return grp32togrp16 (&g16, getgrent32 ());
}
#endif

extern "C" void
endgrent (void)
{
  grent.endgrent ();
}

/* *_filtered functions are called from mkgroup */
void *
setgrent_filtered (int enums, PCWSTR enum_tdoms)
{
  gr_ent *gr = new gr_ent;
  if (gr)
    gr->setgrent (enums, enum_tdoms);
  return (void *) gr;
}

void *
getgrent_filtered (void *gr)
{
  return (void *) ((gr_ent *) gr)->getgrent ();
}

void
endgrent_filtered (void *gr)
{
  ((gr_ent *) gr)->endgrent ();
}

/* timeout_ns (in 100ns units) is set to non-0 when called from
   internal_getlogin.  This restricts fetching of the user's groups at process
   tree startup to a (hopefully) bearable time.  */
int
internal_getgroups (int gidsetsize, gid_t *grouplist, cyg_ldap *pldap,
		    const DWORD timeout_ns)
{
  NTSTATUS status;
  HANDLE tok;
  ULONG size;
  int cnt = 0;
  struct group *grp;

  if (cygheap->user.groups.issetgroups ())
    {
      for (int pg = 0; pg < cygheap->user.groups.sgsids.count (); ++pg)
	if ((grp = internal_getgrsid (cygheap->user.groups.sgsids.sids[pg],
				      pldap)))
	  {
	    if (cnt < gidsetsize)
	      grouplist[cnt] = grp->gr_gid;
	    ++cnt;
	    if (gidsetsize && cnt > gidsetsize)
	      goto error;
	  }
      return cnt;
    }

  /* If impersonated, use impersonation token. */
  tok = cygheap->user.issetuid () ? cygheap->user.primary_token () : hProcToken;

  status = NtQueryInformationToken (tok, TokenGroups, NULL, 0, &size);
  if (NT_SUCCESS (status) || status == STATUS_BUFFER_TOO_SMALL)
    {
      PTOKEN_GROUPS groups = (PTOKEN_GROUPS) alloca (size);

      status = NtQueryInformationToken (tok, TokenGroups, groups, size, &size);
      if (NT_SUCCESS (status))
	{
	  ULONGLONG t0;

	  if (timeout_ns)
	    t0 = GetTickCount_ns ();
	  for (DWORD pg = 0; pg < groups->GroupCount; ++pg)
	    {
	      cygpsid sid = groups->Groups[pg].Sid;
	      if ((grp = internal_getgrsid (sid, pldap)))
		{
		  if ((groups->Groups[pg].Attributes
		      & (SE_GROUP_ENABLED | SE_GROUP_INTEGRITY_ENABLED))
		      && sid != well_known_world_sid)
		    {
		      if (cnt < gidsetsize)
			grouplist[cnt] = grp->gr_gid;
		      ++cnt;
		      if (gidsetsize && cnt > gidsetsize)
			goto error;
		    }
		}
	      if (timeout_ns && GetTickCount_ns () - t0 >= timeout_ns)
		break;
	    }
	}
    }
  else
    debug_printf ("%u = NtQueryInformationToken(NULL) %y", size, status);
  return cnt;

error:
  set_errno (EINVAL);
  return -1;
}

extern "C" int
getgroups32 (int gidsetsize, gid_t *grouplist)
{
  cyg_ldap cldap;

  return internal_getgroups (gidsetsize, grouplist, &cldap);
}

#ifdef __x86_64__
EXPORT_ALIAS (getgroups32, getgroups)
#else
extern "C" int
getgroups (int gidsetsize, __gid16_t *grouplist)
{
  gid_t *grouplist32 = NULL;

  if (gidsetsize < 0)
    {
      set_errno (EINVAL);
      return -1;
    }
  if (gidsetsize > 0 && grouplist)
    grouplist32 = (gid_t *) alloca (gidsetsize * sizeof (gid_t));

  int ret = getgroups32 (gidsetsize, grouplist32);

  if (gidsetsize > 0 && grouplist)
    for (int i = 0; i < ret; ++ i)
      grouplist[i] = grouplist32[i];

  return ret;
}
#endif

/* Core functionality of initgroups and getgrouplist. */
static void
get_groups (const char *user, gid_t gid, cygsidlist &gsids)
{
  cyg_ldap cldap;

  cygheap->user.deimpersonate ();
  struct passwd *pw = internal_getpwnam (user, &cldap);
  struct group *grp = internal_getgrgid (gid, &cldap);
  cygsid usersid, grpsid;
  if (usersid.getfrompw (pw))
    get_server_groups (gsids, usersid, pw);
  if (gid != ILLEGAL_GID && grpsid.getfromgr (grp))
    gsids += grpsid;
  cygheap->user.reimpersonate ();
}

extern "C" int
initgroups32 (const char *user, gid_t gid)
{
  assert (user != NULL);
  cygsidlist tmp_gsids (cygsidlist_auto, 12);
  get_groups (user, gid, tmp_gsids);
  cygsidlist new_gsids (cygsidlist_alloc, tmp_gsids.count ());
  for (int i = 0; i < tmp_gsids.count (); i++)
    new_gsids.sids[i] = tmp_gsids.sids[i];
  new_gsids.count (tmp_gsids.count ());
  cygheap->user.groups.update_supp (new_gsids);
  syscall_printf ( "0 = initgroups(%s, %u)", user, gid);
  return 0;
}

#ifdef __x86_64__
EXPORT_ALIAS (initgroups32, initgroups)
#else
extern "C" int
initgroups (const char *user, __gid16_t gid)
{
  return initgroups32 (user, gid16togid32(gid));
}
#endif

extern "C" int
getgrouplist (const char *user, gid_t gid, gid_t *groups, int *ngroups)
{
  int ret = 0;
  int cnt = 0;
  struct group *grp;
  cyg_ldap cldap;

  /* Note that it's not defined if groups or ngroups may be NULL!
     GLibc does not check the pointers on entry and just uses them.
     FreeBSD calls assert for ngroups and allows a NULL groups if
     *ngroups is 0.  We follow FreeBSD's lead here, but always allow
     a NULL groups pointer. */
  assert (user != NULL);
  assert (ngroups != NULL);

  cygsidlist tmp_gsids (cygsidlist_auto, 12);
  get_groups (user, gid, tmp_gsids);
  for (int i = 0; i < tmp_gsids.count (); i++)
    if ((grp = internal_getgrsid (tmp_gsids.sids[i], &cldap)) != NULL)
      {
	if (groups && cnt < *ngroups)
	  groups[cnt] = grp->gr_gid;
	++cnt;
      }
  if (cnt > *ngroups)
    ret = -1;
  else
    ret = cnt;
  *ngroups = cnt;

  syscall_printf ( "%d = getgrouplist(%s, %u, %p, %d)",
		  ret, user, gid, groups, *ngroups);
  return ret;
}

/* setgroups32: standards? */
extern "C" int
setgroups32 (int ngroups, const gid_t *grouplist)
{
  syscall_printf ("setgroups32 (%d)", ngroups);
  if (ngroups < 0 || (ngroups > 0 && !grouplist))
    {
      set_errno (EINVAL);
      return -1;
    }

  cygsidlist gsids (cygsidlist_alloc, ngroups);
  struct group *grp;
  cyg_ldap cldap;

  if (ngroups && !gsids.sids)
    return -1;

  for (int gidx = 0; gidx < ngroups; ++gidx)
    {
      if ((grp = internal_getgrgid (grouplist[gidx], &cldap))
	  && gsids.addfromgr (grp))
	continue;
      debug_printf ("No sid found for gid %u", grouplist[gidx]);
      gsids.free_sids ();
      set_errno (EINVAL);
      return -1;
    }
  cygheap->user.groups.update_supp (gsids);
  return 0;
}

#ifdef __x86_64__
EXPORT_ALIAS (setgroups32, setgroups)
#else
extern "C" int
setgroups (int ngroups, const __gid16_t *grouplist)
{
  gid_t *grouplist32 = NULL;

  if (ngroups > 0 && grouplist)
    {
      grouplist32 = (gid_t *) alloca (ngroups * sizeof (gid_t));
      if (grouplist32 == NULL)
	return -1;
      for (int i = 0; i < ngroups; i++)
	grouplist32[i] = grouplist[i];
    }
  return setgroups32 (ngroups, grouplist32);
}
#endif