dbus-credentials.c

/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/* dbus-credentials.c Credentials provable through authentication
 *
 * Copyright (C) 2007 Red Hat Inc.
 *
 * SPDX-License-Identifier: AFL-2.1 OR GPL-2.0-or-later
 *
 * Licensed under the Academic Free License version 2.1
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
#include <config.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_SYS_SYSCALL_H
#include <sys/syscall.h>
#endif
#include "dbus-credentials.h"
#include "dbus-internals.h"
#ifdef DBUS_UNIX
#include "dbus-sysdeps-unix.h"
#endif
 
struct DBusCredentials {
  int refcount;
  dbus_uid_t unix_uid;
  dbus_gid_t *unix_gids;
  size_t n_unix_gids;
  dbus_pid_t pid;
  int pid_fd;
  char *windows_sid;
  char *linux_security_label;
  void *adt_audit_data;
  dbus_int32_t adt_audit_data_size;
};
 
DBusCredentials*
_dbus_credentials_new (void)
{
  DBusCredentials *creds;
 
  creds = dbus_new (DBusCredentials, 1);
  if (creds == NULL)
    return NULL;
  
  creds->refcount = 1;
  creds->unix_uid = DBUS_UID_UNSET;
  creds->unix_gids = NULL;
  creds->n_unix_gids = 0;
  creds->pid = DBUS_PID_UNSET;
  creds->pid_fd = -1;
  creds->windows_sid = NULL;
  creds->linux_security_label = NULL;
  creds->adt_audit_data = NULL;
  creds->adt_audit_data_size = 0;
 
  return creds;
}
 
DBusCredentials*
_dbus_credentials_new_from_current_process (void)
{
  DBusCredentials *creds;
 
  creds = _dbus_credentials_new ();
  if (creds == NULL)
    return NULL;
 
  if (!_dbus_credentials_add_from_current_process (creds))
    {
      _dbus_credentials_unref (creds);
      return NULL;
    }
  
  return creds;
}
 
void
_dbus_credentials_ref (DBusCredentials *credentials)
{
  _dbus_assert (credentials->refcount > 0);
  credentials->refcount += 1;
}
 
void
_dbus_credentials_unref (DBusCredentials    *credentials)
{
  _dbus_assert (credentials->refcount > 0);
 
  credentials->refcount -= 1;
  if (credentials->refcount == 0)
    {
      dbus_free (credentials->unix_gids);
      dbus_free (credentials->windows_sid);
      dbus_free (credentials->linux_security_label);
      dbus_free (credentials->adt_audit_data);
#ifdef DBUS_UNIX
      if (credentials->pid_fd >= 0)
        {
          close (credentials->pid_fd);
          credentials->pid_fd = -1;
        }
#endif
      dbus_free (credentials);
    }
}
 
dbus_bool_t
_dbus_credentials_add_pid (DBusCredentials    *credentials,
                           dbus_pid_t          pid)
{
  credentials->pid = pid;
  return TRUE;
}
 
#ifndef DBUS_UNIX
_DBUS_GNUC_NORETURN
#endif
void
_dbus_credentials_take_pid_fd (DBusCredentials    *credentials,
                              int                 pid_fd)
{
#ifdef DBUS_UNIX
  if (credentials->pid_fd >= 0)
    close (credentials->pid_fd);
  credentials->pid_fd = pid_fd;
#else
  _dbus_assert_not_reached ("pidfd never set on non-Unix");
#endif
}
 
dbus_bool_t
_dbus_credentials_add_unix_uid(DBusCredentials    *credentials,
                               dbus_uid_t          uid)
{
  credentials->unix_uid = uid;
  return TRUE;
 
}
 
static int
cmp_gidp (const void *a_, const void *b_)
{
  const dbus_gid_t *a = a_;
  const dbus_gid_t *b = b_;
 
  if (*a < *b)
    return -1;
 
  if (*a > *b)
    return 1;
 
  return 0;
}
 
void
_dbus_credentials_take_unix_gids (DBusCredentials *credentials,
                                  dbus_gid_t      *gids,
                                  size_t           n_gids)
{
  /* So we can compare arrays via a simple memcmp */
  qsort (gids, n_gids, sizeof (dbus_gid_t), cmp_gidp);
 
  dbus_free (credentials->unix_gids);
  credentials->unix_gids = gids;
  credentials->n_unix_gids = n_gids;
}
 
dbus_bool_t
_dbus_credentials_get_unix_gids (DBusCredentials   *credentials,
                                 const dbus_gid_t **gids,
                                 size_t            *n_gids)
{
  if (gids != NULL)
    *gids = credentials->unix_gids;
 
  if (n_gids != NULL)
    *n_gids = credentials->n_unix_gids;
 
  return (credentials->unix_gids != NULL);
}
 
dbus_bool_t
_dbus_credentials_add_windows_sid (DBusCredentials    *credentials,
                                   const char         *windows_sid)
{
  char *copy;
 
  copy = _dbus_strdup (windows_sid);
  if (copy == NULL)
    return FALSE;
 
  dbus_free (credentials->windows_sid);
  credentials->windows_sid = copy;
 
  return TRUE;
}
 
dbus_bool_t
_dbus_credentials_add_linux_security_label (DBusCredentials    *credentials,
                                            const char         *label)
{
  char *copy;
 
  copy = _dbus_strdup (label);
  if (copy == NULL)
    return FALSE;
 
  dbus_free (credentials->linux_security_label);
  credentials->linux_security_label = copy;
 
  return TRUE;
}
 
dbus_bool_t
_dbus_credentials_add_adt_audit_data (DBusCredentials    *credentials,
                                      void               *audit_data,
                                      dbus_int32_t        size)
{
  void *copy;
  copy = _dbus_memdup (audit_data, size);
  if (copy == NULL)
    return FALSE;
 
  dbus_free (credentials->adt_audit_data);
  credentials->adt_audit_data = copy;
  credentials->adt_audit_data_size = size;
 
  return TRUE;
}
 
dbus_bool_t
_dbus_credentials_include (DBusCredentials    *credentials,
                           DBusCredentialType  type)
{
  switch (type)
    {
    case DBUS_CREDENTIAL_UNIX_PROCESS_ID:
      return credentials->pid != DBUS_PID_UNSET ||
             credentials->pid_fd >= 0;
    case DBUS_CREDENTIAL_UNIX_PROCESS_FD:
      return credentials->pid_fd >= 0;
    case DBUS_CREDENTIAL_UNIX_USER_ID:
      return credentials->unix_uid != DBUS_UID_UNSET;
    case DBUS_CREDENTIAL_UNIX_GROUP_IDS:
      return credentials->unix_gids != NULL;
    case DBUS_CREDENTIAL_WINDOWS_SID:
      return credentials->windows_sid != NULL;
    case DBUS_CREDENTIAL_LINUX_SECURITY_LABEL:
      return credentials->linux_security_label != NULL;
    case DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID:
      return credentials->adt_audit_data != NULL;
    default:
      _dbus_assert_not_reached ("Unknown credential enum value");
      return FALSE;
    }
}
 
dbus_pid_t
_dbus_credentials_get_pid (DBusCredentials    *credentials)
{
#ifdef DBUS_UNIX
  dbus_pid_t pid;
 
  if (credentials->pid_fd >= 0)
    {
      pid = _dbus_resolve_pid_fd (credentials->pid_fd);
      if (pid > 0)
        return pid;
    }
#endif
 
  return credentials->pid;
}
 
int
_dbus_credentials_get_pid_fd (DBusCredentials    *credentials)
{
  return credentials->pid_fd;
}
 
dbus_uid_t
_dbus_credentials_get_unix_uid (DBusCredentials    *credentials)
{
  return credentials->unix_uid;
}
 
const char*
_dbus_credentials_get_windows_sid (DBusCredentials    *credentials)
{
  return credentials->windows_sid;
}
 
const char *
_dbus_credentials_get_linux_security_label (DBusCredentials *credentials)
{
  return credentials->linux_security_label;
}
 
void *
_dbus_credentials_get_adt_audit_data (DBusCredentials    *credentials)
{
  return credentials->adt_audit_data;
}
 
dbus_int32_t 
_dbus_credentials_get_adt_audit_data_size (DBusCredentials    *credentials)
{
  return credentials->adt_audit_data_size;
}
 
dbus_bool_t
_dbus_credentials_are_superset (DBusCredentials    *credentials,
                                DBusCredentials    *possible_subset)
{
  return
    (possible_subset->pid == DBUS_PID_UNSET ||
     possible_subset->pid == credentials->pid) &&
    (possible_subset->unix_uid == DBUS_UID_UNSET ||
     possible_subset->unix_uid == credentials->unix_uid) &&
    (possible_subset->unix_gids == NULL ||
     (possible_subset->n_unix_gids == credentials->n_unix_gids &&
      memcmp (possible_subset->unix_gids, credentials->unix_gids,
              sizeof (dbus_gid_t) * credentials->n_unix_gids) == 0)) &&
    (possible_subset->windows_sid == NULL ||
     (credentials->windows_sid && strcmp (possible_subset->windows_sid,
                                          credentials->windows_sid) == 0)) &&
    (possible_subset->linux_security_label == NULL ||
     (credentials->linux_security_label != NULL &&
      strcmp (possible_subset->linux_security_label,
              credentials->linux_security_label) == 0)) &&
    (possible_subset->adt_audit_data == NULL ||
     (credentials->adt_audit_data && memcmp (possible_subset->adt_audit_data,
                                             credentials->adt_audit_data,
                                             credentials->adt_audit_data_size) == 0));
}
 
dbus_bool_t
_dbus_credentials_are_empty (DBusCredentials    *credentials)
{
  return
    credentials->pid == DBUS_PID_UNSET &&
    credentials->pid_fd == -1 &&
    credentials->unix_uid == DBUS_UID_UNSET &&
    credentials->unix_gids == NULL &&
    credentials->n_unix_gids == 0 &&
    credentials->windows_sid == NULL &&
    credentials->linux_security_label == NULL &&
    credentials->adt_audit_data == NULL;
}
 
dbus_bool_t
_dbus_credentials_are_anonymous (DBusCredentials    *credentials)
{
  return
    credentials->unix_uid == DBUS_UID_UNSET &&
    credentials->windows_sid == NULL;
}
 
dbus_bool_t
_dbus_credentials_add_credentials (DBusCredentials    *credentials,
                                   DBusCredentials    *other_credentials)
{
  return
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_UNIX_PROCESS_FD,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_UNIX_PROCESS_ID,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_UNIX_USER_ID,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_UNIX_GROUP_IDS,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_LINUX_SECURITY_LABEL,
                                      other_credentials) &&
    _dbus_credentials_add_credential (credentials,
                                      DBUS_CREDENTIAL_WINDOWS_SID,
                                      other_credentials);
}
 
dbus_bool_t
_dbus_credentials_add_credential (DBusCredentials    *credentials,
                                  DBusCredentialType  which,
                                  DBusCredentials    *other_credentials)
{
  if (which == DBUS_CREDENTIAL_UNIX_PROCESS_ID &&
      other_credentials->pid != DBUS_PID_UNSET)
    {
      if (!_dbus_credentials_add_pid (credentials, other_credentials->pid))
        return FALSE;
    }
  else if (which == DBUS_CREDENTIAL_UNIX_USER_ID &&
           other_credentials->unix_uid != DBUS_UID_UNSET)
    {
      if (!_dbus_credentials_add_unix_uid (credentials, other_credentials->unix_uid))
        return FALSE;
    }
  else if (which == DBUS_CREDENTIAL_UNIX_GROUP_IDS &&
           other_credentials->unix_gids != NULL)
    {
      dbus_gid_t *gids;
 
      gids = dbus_new (dbus_gid_t, other_credentials->n_unix_gids);
 
      if (gids == NULL)
        return FALSE;
 
      memcpy (gids, other_credentials->unix_gids,
              sizeof (dbus_gid_t) * other_credentials->n_unix_gids);
 
      _dbus_credentials_take_unix_gids (credentials, gids,
                                        other_credentials->n_unix_gids);
    }
  else if (which == DBUS_CREDENTIAL_WINDOWS_SID &&
           other_credentials->windows_sid != NULL)
    {
      if (!_dbus_credentials_add_windows_sid (credentials, other_credentials->windows_sid))
        return FALSE;
    } 
  else if (which == DBUS_CREDENTIAL_LINUX_SECURITY_LABEL &&
           other_credentials->linux_security_label != NULL)
    {
      if (!_dbus_credentials_add_linux_security_label (credentials,
            other_credentials->linux_security_label))
        return FALSE;
    }
  else if (which == DBUS_CREDENTIAL_ADT_AUDIT_DATA_ID &&
           other_credentials->adt_audit_data != NULL) 
    {
      if (!_dbus_credentials_add_adt_audit_data (credentials, other_credentials->adt_audit_data, other_credentials->adt_audit_data_size))
        return FALSE;
    }
  /* _dbus_dup() is only available on UNIX platforms. */
#ifdef DBUS_UNIX
  else if (which == DBUS_CREDENTIAL_UNIX_PROCESS_FD &&
      other_credentials->pid_fd >= 0)
    {
      int pid_fd = _dbus_dup (other_credentials->pid_fd, NULL);
 
      if (pid_fd < 0)
        return FALSE;
 
      _dbus_credentials_take_pid_fd (credentials, pid_fd);
    }
#endif
 
  return TRUE;
}
 
void
_dbus_credentials_clear (DBusCredentials    *credentials)
{
  credentials->pid = DBUS_PID_UNSET;
#ifdef DBUS_UNIX
  if (credentials->pid_fd >= 0)
    {
      close (credentials->pid_fd);
      credentials->pid_fd = -1;
    }
#endif
  credentials->unix_uid = DBUS_UID_UNSET;
  dbus_free (credentials->unix_gids);
  credentials->unix_gids = NULL;
  credentials->n_unix_gids = 0;
  dbus_free (credentials->windows_sid);
  credentials->windows_sid = NULL;
  dbus_free (credentials->linux_security_label);
  credentials->linux_security_label = NULL;
  dbus_free (credentials->adt_audit_data);
  credentials->adt_audit_data = NULL;
  credentials->adt_audit_data_size = 0;
}
 
DBusCredentials*
_dbus_credentials_copy (DBusCredentials    *credentials)
{
  DBusCredentials *copy;
 
  copy = _dbus_credentials_new ();
  if (copy == NULL)
    return NULL;
 
  if (!_dbus_credentials_add_credentials (copy, credentials))
    {
      _dbus_credentials_unref (copy);
      return NULL;
    }
 
  return copy;
}
 
dbus_bool_t
_dbus_credentials_same_user (DBusCredentials    *credentials,
                             DBusCredentials    *other_credentials)
{
  /* both windows and unix user must be the same (though pretty much
   * in all conceivable cases, one will be unset)
   */
  return credentials->unix_uid == other_credentials->unix_uid &&
    ((!(credentials->windows_sid || other_credentials->windows_sid)) ||
     (credentials->windows_sid && other_credentials->windows_sid &&
      strcmp (credentials->windows_sid, other_credentials->windows_sid) == 0));
}
 
dbus_bool_t
_dbus_credentials_to_string_append (DBusCredentials    *credentials,
                                    DBusString         *string)
{
  dbus_bool_t join;
 
  join = FALSE;
  if (credentials->unix_uid != DBUS_UID_UNSET)
    {
      if (!_dbus_string_append_printf (string, "uid=" DBUS_UID_FORMAT, credentials->unix_uid))
        goto oom;
      join = TRUE;
    }
  if (credentials->pid != DBUS_PID_UNSET || credentials->pid_fd >= 0)
    {
      if (!_dbus_string_append_printf (string,
                                       "%spid=" DBUS_PID_FORMAT,
                                       join ? " " : "",
                                       _dbus_credentials_get_pid (credentials)))
        goto oom;
      join = TRUE;
    }
 
  if (credentials->unix_gids != NULL)
    {
      size_t i;
 
      for (i = 0; i < credentials->n_unix_gids; i++)
        {
          if (!_dbus_string_append_printf (string, "%sgid=" DBUS_GID_FORMAT,
                                           join ? " " : "",
                                           credentials->unix_gids[i]))
            goto oom;
 
          join = TRUE;
        }
    }
 
  if (credentials->windows_sid != NULL)
    {
      if (!_dbus_string_append_printf (string, "%ssid=%s", join ? " " : "", credentials->windows_sid))
        goto oom;
      join = TRUE;
    }
 
  if (credentials->linux_security_label != NULL)
    {
      if (!_dbus_string_append_printf (string, "%slsm='%s'",
                                       join ? " " : "",
                                       credentials->linux_security_label))
        goto oom;
      join = TRUE;
    }
 
  if (credentials->pid_fd >= 0)
    {
      if (!_dbus_string_append_printf (string, "%spidfd=%d", join ? " " : "", credentials->pid_fd))
        goto oom;
      join = TRUE;
    }
 
  return TRUE;
oom:
  return FALSE;
}
 
/* tests in dbus-credentials-util.c */