newlib/winsup/cygwin/grp.cc

/* grp.cc

   Copyright 1996, 1997, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   2008, 2009, 2011, 2012 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 <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 "pwdgrp.h"

static __group32 *group_buf;
static pwdgrp gr (group_buf);
static char * NO_COPY null_ptr;

bool
pwdgrp::parse_group ()
{
  __group32 &grp = (*group_buf)[curr_lines];
  grp.gr_name = next_str (':');
  if (!*grp.gr_name)
    return false;

  grp.gr_passwd = next_str (':');

  if (!next_num (grp.gr_gid))
    return false;

  int n;
  char *dp = raw_ptr ();
  for (n = 0; *next_str (','); n++)
    continue;

  grp.gr_mem = &null_ptr;
  if (n)
    {
      char **namearray = (char **) calloc (n + 1, sizeof (char *));
      if (namearray)
	{
	  for (int i = 0; i < n; i++, dp = strchr (dp, '\0') + 1)
	    namearray[i] = dp;
	  grp.gr_mem = namearray;
	}
    }

  return true;
}

/* Cygwin internal */
/* Read in /etc/group and save contents in the group cache */
/* This sets group_in_memory_p to 1 so functions in this file can
   tell that /etc/group has been read in */
void
pwdgrp::read_group ()
{
  for (int i = 0; i < gr.curr_lines; i++)
    if ((*group_buf)[i].gr_mem != &null_ptr)
      free ((*group_buf)[i].gr_mem);

  load (L"\\etc\\group");

  /* Complete /etc/group in memory if needed */
  if (!internal_getgrgid (myself->gid))
    {
      static char linebuf [200];
      char group_name [UNLEN + 1] = "mkgroup";
      char strbuf[128] = "";
      struct __group32 *gr;

      cygheap->user.groups.pgsid.string (strbuf);
      if ((gr = internal_getgrsid (cygheap->user.groups.pgsid)))
	snprintf (group_name, sizeof (group_name),
		  "passwd/group_GID_clash(%lu/%lu)", myself->gid, gr->gr_gid);
      if (myself->uid == UNKNOWN_UID)
	strcpy (group_name, "mkpasswd"); /* Feedback... */
      snprintf (linebuf, sizeof (linebuf), "%s:%s:%lu:%s",
		group_name, strbuf, myself->gid, cygheap->user.name ());
      debug_printf ("Completing /etc/group: %s", linebuf);
      add_line (linebuf);
    }
  static char NO_COPY pretty_ls[] = "????????::-1:";
  add_line (pretty_ls);
}

muto NO_COPY pwdgrp::pglock;

pwdgrp::pwdgrp (passwd *&pbuf) :
  pwdgrp_buf_elem_size (sizeof (*pbuf)), passwd_buf (&pbuf)
{
  read = &pwdgrp::read_passwd;
  parse = &pwdgrp::parse_passwd;
  pglock.init ("pglock");
}

pwdgrp::pwdgrp (__group32 *&gbuf) :
  pwdgrp_buf_elem_size (sizeof (*gbuf)), group_buf (&gbuf)
{
  read = &pwdgrp::read_group;
  parse = &pwdgrp::parse_group;
  pglock.init ("pglock");
}

struct __group32 *
internal_getgrsid (cygpsid &sid)
{
  char sid_string[128];

  gr.refresh (false);

  if (sid.string (sid_string))
    for (int i = 0; i < gr.curr_lines; i++)
      if (!strcmp (sid_string, group_buf[i].gr_passwd))
	return group_buf + i;
  return NULL;
}

struct __group32 *
internal_getgrgid (__gid32_t gid, bool check)
{
  gr.refresh (check);

  for (int i = 0; i < gr.curr_lines; i++)
    if (group_buf[i].gr_gid == gid)
      return group_buf + i;
  return NULL;
}

struct __group32 *
internal_getgrnam (const char *name, bool check)
{
  gr.refresh (check);

  for (int i = 0; i < gr.curr_lines; i++)
    if (strcasematch (group_buf[i].gr_name, name))
      return group_buf + i;

  /* Didn't find requested group */
  return NULL;
}

static struct __group16 *
grp32togrp16 (struct __group16 *gp16, struct __group32 *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;
}

extern "C" int
getgrgid_r (__gid32_t gid, struct __group32 *grp, char *buffer, size_t bufsize,
	    struct __group32 **result)
{
  *result = NULL;

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

  struct __group32 *tempgr = internal_getgrgid (gid, true);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* check needed buffer size. */
  int i;
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    needsize += strlen (tempgr->gr_mem[i]) + 1 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of tempgr */
  *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);
  buffer = (char *) grp->gr_mem + (i + 1) * sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    buffer = stpcpy (grp->gr_mem[i] = buffer, tempgr->gr_mem[i]) + 1;
  grp->gr_mem[i] = NULL;
  return 0;
}

extern "C" struct __group32 *
getgrgid32 (__gid32_t gid)
{
  return internal_getgrgid (gid, true);
}

extern "C" struct __group16 *
getgrgid (__gid16_t gid)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

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

extern "C" int
getgrnam_r (const char *nam, struct __group32 *grp, char *buffer,
	    size_t bufsize, struct __group32 **result)
{
  *result = NULL;

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

  struct __group32 *tempgr = internal_getgrnam (nam, true);
  pthread_testcancel ();
  if (!tempgr)
    return 0;

  /* check needed buffer size. */
  int i;
  size_t needsize = strlen (tempgr->gr_name) + strlen (tempgr->gr_passwd)
		    + 2 + sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    needsize += strlen (tempgr->gr_mem[i]) + 1 + sizeof (char *);
  if (needsize > bufsize)
    return ERANGE;

  /* make a copy of tempgr */
  *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);
  buffer = (char *) grp->gr_mem + (i + 1) * sizeof (char *);
  for (i = 0; tempgr->gr_mem[i]; ++i)
    buffer = stpcpy (grp->gr_mem[i] = buffer, tempgr->gr_mem[i]) + 1;
  grp->gr_mem[i] = NULL;
  return 0;
}

extern "C" struct __group32 *
getgrnam32 (const char *name)
{
  return internal_getgrnam (name, true);
}

extern "C" struct __group16 *
getgrnam (const char *name)
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

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

extern "C" void
endgrent ()
{
  _my_tls.locals.grp_pos = 0;
}

extern "C" struct __group32 *
getgrent32 ()
{
  if (_my_tls.locals.grp_pos == 0)
    gr.refresh (true);
  if (_my_tls.locals.grp_pos < gr.curr_lines)
    return group_buf + _my_tls.locals.grp_pos++;

  return NULL;
}

extern "C" struct __group16 *
getgrent ()
{
  static struct __group16 g16;	/* FIXME: thread-safe? */

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

extern "C" void
setgrent ()
{
  _my_tls.locals.grp_pos = 0;
}

/* Internal function. ONLY USE THIS INTERNALLY, NEVER `getgrent'!!! */
struct __group32 *
internal_getgrent (int pos)
{
  gr.refresh (false);

  if (pos < gr.curr_lines)
    return group_buf + pos;
  return NULL;
}

int
internal_getgroups (int gidsetsize, __gid32_t *grouplist, cygpsid * srchsid)
{
  NTSTATUS status;
  HANDLE hToken = NULL;
  ULONG size;
  int cnt = 0;
  struct __group32 *gr;

  if (!srchsid && cygheap->user.groups.issetgroups ())
    {
      cygsid sid;
      for (int gidx = 0; (gr = internal_getgrent (gidx)); ++gidx)
	if (sid.getfromgr (gr))
	  for (int pg = 0; pg < cygheap->user.groups.sgsids.count (); ++pg)
	    if (sid == cygheap->user.groups.sgsids.sids[pg]
		&& sid != well_known_world_sid)
	      {
		if (cnt < gidsetsize)
		  grouplist[cnt] = gr->gr_gid;
		++cnt;
		if (gidsetsize && cnt > gidsetsize)
		  goto error;
		break;
	      }
      return cnt;
    }


  /* If impersonated, use impersonation token. */
  if (cygheap->user.issetuid ())
    hToken = cygheap->user.primary_token ();
  else
    hToken = hProcToken;

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

      status = NtQueryInformationToken (hToken, TokenGroups, groups,
					size, &size);
      if (NT_SUCCESS (status))
	{
	  cygsid sid;

	  if (srchsid)
	    {
	      for (DWORD pg = 0; pg < groups->GroupCount; ++pg)
		if ((cnt = (*srchsid == groups->Groups[pg].Sid)))
		  break;
	    }
	  else
	    for (int gidx = 0; (gr = internal_getgrent (gidx)); ++gidx)
	      if (sid.getfromgr (gr))
		for (DWORD pg = 0; pg < groups->GroupCount; ++pg)
		  if (sid == groups->Groups[pg].Sid
		      && (groups->Groups[pg].Attributes
			  & (SE_GROUP_ENABLED | SE_GROUP_INTEGRITY_ENABLED))
		      && sid != well_known_world_sid)
		    {
		      if (cnt < gidsetsize)
			grouplist[cnt] = gr->gr_gid;
		      ++cnt;
		      if (gidsetsize && cnt > gidsetsize)
			goto error;
		      break;
		    }
	}
    }
  else
    debug_printf ("%lu = NtQueryInformationToken(NULL) %p", size, status);
  return cnt;

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

extern "C" int
getgroups32 (int gidsetsize, __gid32_t *grouplist)
{
  return internal_getgroups (gidsetsize, grouplist);
}

extern "C" int
getgroups (int gidsetsize, __gid16_t *grouplist)
{
  __gid32_t *grouplist32 = NULL;

  if (gidsetsize < 0)
    {
      set_errno (EINVAL);
      return -1;
    }
  if (gidsetsize > 0 && grouplist)
    grouplist32 = (__gid32_t *) alloca (gidsetsize * sizeof (__gid32_t));

  int ret = internal_getgroups (gidsetsize, grouplist32);

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

  return ret;
}

/* Core functionality of initgroups and getgrouplist. */
static int
get_groups (const char *user, gid_t gid, cygsidlist &gsids)
{
  int ret = -1;

  cygheap->user.deimpersonate ();
  struct passwd *pw = internal_getpwnam (user);
  struct __group32 *gr = internal_getgrgid (gid);
  cygsid usersid, grpsid;
  if (!usersid.getfrompw (pw) || !grpsid.getfromgr (gr))
    set_errno (EINVAL);
  else if (get_server_groups (gsids, usersid, pw))
    {
      gsids += grpsid;
      ret = 0;
    }
  cygheap->user.reimpersonate ();
  return ret;
}

extern "C" int
initgroups32 (const char *user, __gid32_t gid)
{
  int ret;

  assert (user != NULL);
  cygsidlist tmp_gsids (cygsidlist_auto, 12);
  if (!(ret = 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 ( "%d = initgroups(%s, %u)", ret, user, gid);
  return ret;
}

extern "C" int
initgroups (const char *user, __gid16_t gid)
{
  return initgroups32 (user, gid16togid32(gid));
}

extern "C" int
getgrouplist (const char *user, gid_t gid, gid_t *groups, int *ngroups)
{
  int ret;

  /* 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);
  if (!(ret = get_groups (user, gid, tmp_gsids)))
    {
      int cnt = 0;
      for (int i = 0; i < tmp_gsids.count (); i++)
	{
	  struct __group32 *gr = internal_getgrsid (tmp_gsids.sids[i]);
	  if (gr)
	    {
	      if (groups && cnt < *ngroups)
		groups[cnt] = gr->gr_gid;
	      ++cnt;
	    }
	}
      if (cnt > *ngroups)
	ret = -1;
      *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 __gid32_t *grouplist)
{
  syscall_printf ("setgroups32 (%d)", ngroups);
  if (ngroups < 0 || (ngroups > 0 && !grouplist))
    {
      set_errno (EINVAL);
      return -1;
    }

  cygsidlist gsids (cygsidlist_alloc, ngroups);
  struct __group32 *gr;

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

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

extern "C" int
setgroups (int ngroups, const __gid16_t *grouplist)
{
  __gid32_t *grouplist32 = NULL;

  if (ngroups > 0 && grouplist)
    {
      grouplist32 = (__gid32_t *) alloca (ngroups * sizeof (__gid32_t));
      if (grouplist32 == NULL)
	return -1;
      for (int i = 0; i < ngroups; i++)
	grouplist32[i] = grouplist[i];
    }
  return setgroups32 (ngroups, grouplist32);
}