/src/samba/source3/auth/token_util.c

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/*
 *  Unix SMB/CIFS implementation.
 *  Authentication utility functions
 *  Copyright (C) Andrew Tridgell 1992-1998
 *  Copyright (C) Andrew Bartlett 2001
 *  Copyright (C) Jeremy Allison 2000-2001
 *  Copyright (C) Rafal Szczesniak 2002
 *  Copyright (C) Volker Lendecke 2006
 *  Copyright (C) Michael Adam 2007
 *
 *  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 3 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, see <http://www.gnu.org/licenses/>.
 */

/* functions moved from auth/auth_util.c to minimize linker deps */

#include "includes.h"
#include "lib/util_unixsids.h"
#include "system/passwd.h"
#include "auth.h"
#include "secrets.h"
#include "../lib/util/memcache.h"
#include "../librpc/gen_ndr/netlogon.h"
#include "../libcli/security/security.h"
#include "../lib/util/util_pw.h"
#include "passdb.h"
#include "lib/privileges.h"

/****************************************************************************
 Check for a SID in an struct security_token
****************************************************************************/

bool nt_token_check_sid ( const struct dom_sid *sid, const struct security_token *token )
{
  if ( !sid || !token )
    return False;

  return security_token_has_sid(token, sid);
}

bool nt_token_check_domain_rid( struct security_token *token, uint32_t rid )
{
  struct dom_sid domain_sid;

  /* if we are a domain member, the get the domain SID, else for
     a DC or standalone server, use our own SID */

  if ( lp_server_role() == ROLE_DOMAIN_MEMBER ) {
    if ( !secrets_fetch_domain_sid( lp_workgroup(),
            &domain_sid ) ) {
      DEBUG(1,("nt_token_check_domain_rid: Cannot lookup "
         "SID for domain [%s]\n", lp_workgroup()));
      return False;
    }
  }
  else
    sid_copy( &domain_sid, get_global_sam_sid() );

  sid_append_rid( &domain_sid, rid );

  return nt_token_check_sid( &domain_sid, token );\
}

/******************************************************************************
 Create a token for the root user to be used internally by smbd.
 This is similar to running under the context of the LOCAL_SYSTEM account
 in Windows.  This is a read-only token.  Do not modify it or free() it.
 Create a copy if you need to change it.
******************************************************************************/

NTSTATUS get_root_nt_token( struct security_token **token )
{
  struct security_token *for_cache;
  struct dom_sid u_sid, g_sid;
  struct passwd *pw;
  void *cache_data;
  NTSTATUS status = NT_STATUS_OK;

  cache_data = memcache_lookup_talloc(
    NULL, SINGLETON_CACHE_TALLOC,
    data_blob_string_const_null("root_nt_token"));

  if (cache_data != NULL) {
    *token = talloc_get_type_abort(
      cache_data, struct security_token);
    return NT_STATUS_OK;
  }

  if ( !(pw = getpwuid(0)) ) {
    if ( !(pw = getpwnam("root")) ) {
      DBG_ERR("get_root_nt_token: both getpwuid(0) "
        "and getpwnam(\"root\") failed!\n");
      return NT_STATUS_NO_SUCH_USER;
    }
  }

  /* get the user and primary group SIDs; although the
     BUILTIN\Administrators SId is really the one that matters here */

  uid_to_sid(&u_sid, pw->pw_uid);
  gid_to_sid(&g_sid, pw->pw_gid);

  status = create_local_nt_token(talloc_tos(), &u_sid, False,
              1, &global_sid_Builtin_Administrators, token);
  if (!NT_STATUS_IS_OK(status)) {
    return status;
  }

  security_token_set_privilege(*token, SEC_PRIV_DISK_OPERATOR);

  for_cache = *token;

  memcache_add_talloc(
    NULL, SINGLETON_CACHE_TALLOC,
    data_blob_string_const_null("root_nt_token"), &for_cache);

  return status;
}


/*
 * Add alias SIDs from memberships within the partially created token SID list
 */

NTSTATUS add_aliases(const struct dom_sid *domain_sid,
         struct security_token *token)
{
  uint32_t *aliases;
  size_t i, num_aliases;
  NTSTATUS status;
  TALLOC_CTX *tmp_ctx;

  if (!(tmp_ctx = talloc_init("add_aliases"))) {
    return NT_STATUS_NO_MEMORY;
  }

  aliases = NULL;
  num_aliases = 0;

  status = pdb_enum_alias_memberships(tmp_ctx, domain_sid,
              token->sids,
              token->num_sids,
              &aliases, &num_aliases);

  if (!NT_STATUS_IS_OK(status)) {
    DEBUG(10, ("pdb_enum_alias_memberships failed: %s\n",
         nt_errstr(status)));
    goto done;
  }

  for (i=0; i<num_aliases; i++) {
    struct dom_sid alias_sid;
    sid_compose(&alias_sid, domain_sid, aliases[i]);
    status = add_sid_to_array_unique(token, &alias_sid,
             &token->sids,
             &token->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      DEBUG(0, ("add_sid_to_array failed\n"));
      goto done;
    }
  }

done:
  TALLOC_FREE(tmp_ctx);
  return NT_STATUS_OK;
}

/*******************************************************************
*******************************************************************/

static NTSTATUS add_builtin_administrators(struct security_token *token,
             const struct dom_sid *dom_sid)
{
  struct dom_sid domadm;
  NTSTATUS status;

  /* nothing to do if we aren't in a domain */

  if ( !(IS_DC || lp_server_role()==ROLE_DOMAIN_MEMBER) ) {
    return NT_STATUS_OK;
  }

  /* Find the Domain Admins SID */

  if ( IS_DC ) {
    sid_copy( &domadm, get_global_sam_sid() );
  } else {
    if (dom_sid == NULL) {
      return NT_STATUS_INVALID_PARAMETER_MIX;
    }
    sid_copy(&domadm, dom_sid);
  }
  sid_append_rid( &domadm, DOMAIN_RID_ADMINS );

  /* Add Administrators if the user beloongs to Domain Admins */

  if ( nt_token_check_sid( &domadm, token ) ) {
    status = add_sid_to_array(token,
            &global_sid_Builtin_Administrators,
            &token->sids, &token->num_sids);
  if (!NT_STATUS_IS_OK(status)) {
      return status;
    }
  }

  return NT_STATUS_OK;
}

static NTSTATUS add_builtin_guests(struct security_token *token,
           const struct dom_sid *dom_sid)
{
  struct dom_sid tmp_sid;
  NTSTATUS status;

  /*
   * First check the local GUEST account.
   */
  sid_compose(&tmp_sid, get_global_sam_sid(), DOMAIN_RID_GUEST);

  if (nt_token_check_sid(&tmp_sid, token)) {
    status = add_sid_to_array_unique(token,
          &global_sid_Builtin_Guests,
          &token->sids, &token->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }

    return NT_STATUS_OK;
  }

  /*
   * First check the local GUESTS group.
   */
  sid_compose(&tmp_sid, get_global_sam_sid(), DOMAIN_RID_GUESTS);

  if (nt_token_check_sid(&tmp_sid, token)) {
    status = add_sid_to_array_unique(token,
          &global_sid_Builtin_Guests,
          &token->sids, &token->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }

    return NT_STATUS_OK;
  }

  if (lp_server_role() != ROLE_DOMAIN_MEMBER) {
    return NT_STATUS_OK;
  }

  if (dom_sid == NULL) {
    return NT_STATUS_INVALID_PARAMETER_MIX;
  }

  /*
   * First check the domain GUESTS group.
   */
  sid_copy(&tmp_sid, dom_sid);
  sid_append_rid(&tmp_sid, DOMAIN_RID_GUESTS);

  if (nt_token_check_sid(&tmp_sid, token)) {
    status = add_sid_to_array_unique(token,
          &global_sid_Builtin_Guests,
          &token->sids, &token->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }

    return NT_STATUS_OK;
  }

  return NT_STATUS_OK;
}

static NTSTATUS add_local_groups(struct security_token *result,
         bool is_guest);

NTSTATUS get_user_sid_info3_and_extra(const struct netr_SamInfo3 *info3,
              const struct extra_auth_info *extra,
              struct dom_sid *sid)
{
  /* USER SID */
  if (info3->base.rid == (uint32_t)(-1)) {
    /* this is a signal the user was fake and generated,
     * the actual SID we want to use is stored in the extra
     * sids */
    if (is_null_sid(&extra->user_sid)) {
      /* we couldn't find the user sid, bail out */
      DEBUG(3, ("Invalid user SID\n"));
      return NT_STATUS_UNSUCCESSFUL;
    }
    sid_copy(sid, &extra->user_sid);
  } else {
    sid_copy(sid, info3->base.domain_sid);
    sid_append_rid(sid, info3->base.rid);
  }
  return NT_STATUS_OK;
}

static struct security_token *init_local_nt_token(TALLOC_CTX *mem_ctx) 
{
  /*
   * We do not have a method to populate the claims into this
   * buffer in the source3/ stack.  When that changes, we will
   * instead make this optional based on lp_acl_claims_evaluation()
   */

  struct security_token *result
    = security_token_initialise(mem_ctx,
              CLAIMS_EVALUATION_NEVER);

  if (result == NULL) {
    DBG_ERR("talloc failed for security_token\n");
    return NULL;
  }

  return result;
}

NTSTATUS create_local_nt_token_from_info3(TALLOC_CTX *mem_ctx,
            bool is_guest,
            const struct netr_SamInfo3 *info3,
            const struct extra_auth_info *extra,
            struct security_token **ntok)
{
  struct security_token *usrtok = NULL;
  uint32_t session_info_flags = 0;
  NTSTATUS status;
  uint32_t i;

  DEBUG(10, ("Create local NT token for %s\n",
       info3->base.account_name.string));

  usrtok = init_local_nt_token(mem_ctx);
  if (!usrtok) {
    return NT_STATUS_NO_MEMORY;
  }

  /* Add the user and primary group sid FIRST */
  /* check if the user rid is the special "Domain Guests" rid.
   * If so pick the first sid for the extra sids instead as it
   * is a local fake account */
  usrtok->sids = talloc_array(usrtok, struct dom_sid, 2);
  if (!usrtok->sids) {
    TALLOC_FREE(usrtok);
    return NT_STATUS_NO_MEMORY;
  }
  usrtok->num_sids = 2;

  status = get_user_sid_info3_and_extra(info3, extra, &usrtok->sids[0]);
  if (!NT_STATUS_IS_OK(status)) {
    TALLOC_FREE(usrtok);
    return status;
  }

  /* GROUP SID */
  if (info3->base.primary_gid == (uint32_t)(-1)) {
    /* this is a signal the user was fake and generated,
     * the actual SID we want to use is stored in the extra
     * sids */
    if (is_null_sid(&extra->pgid_sid)) {
      /* we couldn't find the user sid, bail out */
      DEBUG(3, ("Invalid group SID\n"));
      TALLOC_FREE(usrtok);
      return NT_STATUS_UNSUCCESSFUL;
    }
    sid_copy(&usrtok->sids[1], &extra->pgid_sid);
  } else {
    sid_copy(&usrtok->sids[1], info3->base.domain_sid);
    sid_append_rid(&usrtok->sids[1],
        info3->base.primary_gid);
  }

  /* Now the SIDs we got from authentication. These are the ones from
   * the info3 struct or from the pdb_enum_group_memberships, depending
   * on who authenticated the user.
   * Note that we start the for loop at "1" here, we already added the
   * first group sid as primary above. */

  for (i = 0; i < info3->base.groups.count; i++) {
    struct dom_sid tmp_sid;

    sid_copy(&tmp_sid, info3->base.domain_sid);
    sid_append_rid(&tmp_sid, info3->base.groups.rids[i].rid);

    status = add_sid_to_array_unique(usrtok, &tmp_sid,
             &usrtok->sids,
             &usrtok->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      DEBUG(3, ("Failed to add SID to nt token\n"));
      TALLOC_FREE(usrtok);
      return status;
    }
  }

  /* now also add extra sids if they are not the special user/group
   * sids */
  for (i = 0; i < info3->sidcount; i++) {
    status = add_sid_to_array_unique(usrtok,
             info3->sids[i].sid,
             &usrtok->sids,
             &usrtok->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      DEBUG(3, ("Failed to add SID to nt token\n"));
      TALLOC_FREE(usrtok);
      return status;
    }
  }

  status = add_local_groups(usrtok, is_guest);
  if (!NT_STATUS_IS_OK(status)) {
    DEBUG(3, ("Failed to add local groups\n"));
    TALLOC_FREE(usrtok);
    return status;
  }

  session_info_flags |= AUTH_SESSION_INFO_DEFAULT_GROUPS;
  if (!is_guest) {
    session_info_flags |= AUTH_SESSION_INFO_AUTHENTICATED;
  }

  status = finalize_local_nt_token(usrtok, session_info_flags);
  if (!NT_STATUS_IS_OK(status)) {
    DEBUG(3, ("Failed to finalize nt token\n"));
    TALLOC_FREE(usrtok);
    return status;
  }

  *ntok = usrtok;
  return NT_STATUS_OK;
}

/*******************************************************************
 Create a NT token for the user, expanding local aliases
*******************************************************************/

NTSTATUS create_local_nt_token(TALLOC_CTX *mem_ctx,
              const struct dom_sid *user_sid,
              bool is_guest,
              int num_groupsids,
              const struct dom_sid *groupsids,
              struct security_token **token)
{
  struct security_token *result = NULL;
  int i;
  NTSTATUS status;
  uint32_t session_info_flags = 0;
  struct dom_sid_buf buf;

  DEBUG(10, ("Create local NT token for %s\n",
       dom_sid_str_buf(user_sid, &buf)));

  result = init_local_nt_token(mem_ctx);
  if (result == NULL) {
    status = NT_STATUS_NO_MEMORY;
    goto err;
  }

  /* Add the user and primary group sid */

  status = add_sid_to_array(result, user_sid,
          &result->sids, &result->num_sids);
  if (!NT_STATUS_IS_OK(status)) {
    goto err;
  }

  /* For guest, num_groupsids may be zero. */
  if (num_groupsids) {
    status = add_sid_to_array(result, &groupsids[0],
            &result->sids,
            &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      goto err;
    }
  }

  /* Now the SIDs we got from authentication. These are the ones from
   * the info3 struct or from the pdb_enum_group_memberships, depending
   * on who authenticated the user.
   * Note that we start the for loop at "1" here, we already added the
   * first group sid as primary above. */

  for (i=1; i<num_groupsids; i++) {
    status = add_sid_to_array_unique(result, &groupsids[i],
             &result->sids,
             &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      goto err;
    }
  }

  status = add_local_groups(result, is_guest);
  if (!NT_STATUS_IS_OK(status)) {
    goto err;
  }

  session_info_flags |= AUTH_SESSION_INFO_DEFAULT_GROUPS;
  if (!is_guest) {
    session_info_flags |= AUTH_SESSION_INFO_AUTHENTICATED;
  }

  status = finalize_local_nt_token(result, session_info_flags);
  if (!NT_STATUS_IS_OK(status)) {
    goto err;
  }

  if (is_guest) {
    /*
     * It's ugly, but for now it's
     * needed to add Builtin_Guests
     * here, the "local" token only
     * consist of S-1-22-* SIDs
     * and finalize_local_nt_token()
     * doesn't have the chance to
     * to detect it need to
     * add Builtin_Guests via
     * add_builtin_guests().
     */
    status = add_sid_to_array_unique(result,
             &global_sid_Builtin_Guests,
             &result->sids,
             &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      DEBUG(3, ("Failed to add SID to nt token\n"));
      goto err;
    }
  }

  *token = result;
  return NT_STATUS_SUCCESS;

err:
  TALLOC_FREE(result);
  return status;
}

/***************************************************
 Merge in any groups from /etc/group.
***************************************************/

static NTSTATUS add_local_groups(struct security_token *result,
         bool is_guest)
{
  gid_t *gids = NULL;
  uint32_t getgroups_num_group_sids = 0;
  struct passwd *pass = NULL;
  TALLOC_CTX *tmp_ctx = talloc_stackframe();
  uint32_t i;

  if (is_guest) {
    /*
     * Guest is a special case. It's always
     * a user that can be looked up, but
     * result->sids[0] is set to DOMAIN\Guest.
     * Lookup by account name instead.
     */
    pass = Get_Pwnam_alloc(tmp_ctx, lp_guest_account());
  } else {
    uid_t uid;

    /* For non-guest result->sids[0] is always the user sid. */
    if (!sid_to_uid(&result->sids[0], &uid)) {
      /*
       * Non-mappable SID like SYSTEM.
       * Can't be in any /etc/group groups.
       */
      TALLOC_FREE(tmp_ctx);
      return NT_STATUS_OK;
    }

    pass = getpwuid_alloc(tmp_ctx, uid);
    if (pass == NULL) {
      struct dom_sid_buf buf;
      DBG_ERR("SID %s -> getpwuid(%u) failed, is nsswitch configured?\n",
        dom_sid_str_buf(&result->sids[0], &buf),
        (unsigned int)uid);
      TALLOC_FREE(tmp_ctx);
      return NT_STATUS_NO_SUCH_USER;
    }
  }

  if (!pass) {
    TALLOC_FREE(tmp_ctx);
    return NT_STATUS_UNSUCCESSFUL;
  }

  /*
   * Now we must get any groups this user has been
   * added to in /etc/group and merge them in.
   * This has to be done in every code path
   * that creates an NT token, as remote users
   * may have been added to the local /etc/group
   * database. Tokens created merely from the
   * info3 structs (via the DC or via the krb5 PAC)
   * won't have these local groups. Note the
   * groups added here will only be UNIX groups
   * (S-1-22-2-XXXX groups) as getgroups_unix_user()
   * turns off winbindd before calling getgroups().
   *
   * NB. This is duplicating work already
   * done in the 'unix_user:' case of
   * create_token_from_sid() but won't
   * do anything other than be inefficient
   * in that case.
   */

  if (!getgroups_unix_user(tmp_ctx, pass->pw_name, pass->pw_gid,
      &gids, &getgroups_num_group_sids)) {
    DEBUG(1, ("getgroups_unix_user for user %s failed\n",
      pass->pw_name));
    TALLOC_FREE(tmp_ctx);
    return NT_STATUS_UNSUCCESSFUL;
  }

  for (i=0; i<getgroups_num_group_sids; i++) {
    NTSTATUS status;
    struct dom_sid grp_sid;
    gid_to_sid(&grp_sid, gids[i]);

    status = add_sid_to_array_unique(result,
           &grp_sid,
           &result->sids,
           &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      DEBUG(3, ("Failed to add UNIX SID to nt token\n"));
      TALLOC_FREE(tmp_ctx);
      return status;
    }
  }
  TALLOC_FREE(tmp_ctx);
  return NT_STATUS_OK;
}

NTSTATUS finalize_local_nt_token(struct security_token *result,
         uint32_t session_info_flags)
{
  struct dom_sid _dom_sid = { 0, };
  struct dom_sid *domain_sid = NULL;
  NTSTATUS status;
  struct acct_info *info;
  bool ok;

  result->privilege_mask = 0;
  result->rights_mask = 0;

  if (result->num_sids == 0) {
    return NT_STATUS_INVALID_TOKEN;
  }

  if (session_info_flags & AUTH_SESSION_INFO_DEFAULT_GROUPS) {
    status = add_sid_to_array(result, &global_sid_World,
            &result->sids, &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }
    status = add_sid_to_array(result, &global_sid_Network,
            &result->sids, &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }
  }

  /*
   * Don't expand nested groups of system, anonymous etc
   *
   * Note that they still get SID_WORLD and SID_NETWORK
   * for now in order let existing tests pass.
   *
   * But SYSTEM doesn't get AUTHENTICATED_USERS
   * and ANONYMOUS doesn't get BUILTIN GUESTS anymore.
   */
  if (security_token_is_anonymous(result)) {
    return NT_STATUS_OK;
  }
  if (security_token_is_system(result)) {
    result->privilege_mask = ~0;
    return NT_STATUS_OK;
  }

  if (session_info_flags & AUTH_SESSION_INFO_AUTHENTICATED) {
    status = add_sid_to_array(result,
            &global_sid_Authenticated_Users,
            &result->sids,
            &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }
  }

  /* Add in BUILTIN sids */

  become_root();
  ok = secrets_fetch_domain_sid(lp_workgroup(), &_dom_sid);
  if (ok) {
    domain_sid = &_dom_sid;
  } else {
    DEBUG(3, ("Failed to fetch domain sid for %s\n",
        lp_workgroup()));
  }
  unbecome_root();

  info = talloc_zero(talloc_tos(), struct acct_info);
  if (info == NULL) {
    DEBUG(0, ("talloc failed!\n"));
    return NT_STATUS_NO_MEMORY;
  }

  /* Deal with the BUILTIN\Administrators group.  If the SID can
     be resolved then assume that the add_aliasmem( S-1-5-32 )
     handled it. */

  status = pdb_get_aliasinfo(&global_sid_Builtin_Administrators, info);
  if (!NT_STATUS_IS_OK(status)) {

    become_root();
    status = create_builtin_administrators(domain_sid);
    unbecome_root();

    if (NT_STATUS_EQUAL(status, NT_STATUS_PROTOCOL_UNREACHABLE)) {
      /* Add BUILTIN\Administrators directly to token. */
      status = add_builtin_administrators(result, domain_sid);
      if ( !NT_STATUS_IS_OK(status) ) {
        DEBUG(3, ("Failed to check for local "
            "Administrators membership (%s)\n",
            nt_errstr(status)));
      }
    } else if (!NT_STATUS_IS_OK(status)) {
      DEBUG(2, ("WARNING: Failed to create "
          "BUILTIN\\Administrators group!  Can "
          "Winbind allocate gids?\n"));
    }
  }

  /* Deal with the BUILTIN\Users group.  If the SID can
     be resolved then assume that the add_aliasmem( S-1-5-32 )
     handled it. */

  status = pdb_get_aliasinfo(&global_sid_Builtin_Users, info);
  if (!NT_STATUS_IS_OK(status)) {

    become_root();
    status = create_builtin_users(domain_sid);
    unbecome_root();

    if (!NT_STATUS_EQUAL(status, NT_STATUS_PROTOCOL_UNREACHABLE) &&
        !NT_STATUS_IS_OK(status))
    {
      DEBUG(2, ("WARNING: Failed to create BUILTIN\\Users group! "
          "Can Winbind allocate gids?\n"));
    }
  }

  /*
   * Deal with the BUILTIN\Guests group.  If the SID can
   * be resolved then assume that the add_aliasmem( S-1-5-32 )
   * handled it.
   */
  status = pdb_get_aliasinfo(&global_sid_Builtin_Guests, info);
  if (!NT_STATUS_IS_OK(status)) {

    become_root();
    status = create_builtin_guests(domain_sid);
    unbecome_root();

    /*
     * NT_STATUS_PROTOCOL_UNREACHABLE:
     * => winbindd is not running.
     *
     * NT_STATUS_ACCESS_DENIED:
     * => no idmap config at all
     * and wbint_AllocateGid()/winbind_allocate_gid()
     * failed.
     *
     * NT_STATUS_NO_SUCH_GROUP:
     * => no idmap config at all and
     * "tdbsam:map builtin = no" means
     * wbint_Sids2UnixIDs() fails.
     */
    if (NT_STATUS_EQUAL(status, NT_STATUS_PROTOCOL_UNREACHABLE) ||
        NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED) ||
        NT_STATUS_EQUAL(status, NT_STATUS_NO_SUCH_GROUP)) {
      /*
       * Add BUILTIN\Guests directly to token.
       * But only if the token already indicates
       * real guest access by:
       * - local GUEST account
       * - local GUESTS group
       * - domain GUESTS group
       *
       * Even if a user was authenticated, it
       * can be member of a guest related group.
       */
      status = add_builtin_guests(result, domain_sid);
      if (!NT_STATUS_IS_OK(status)) {
        DEBUG(3, ("Failed to check for local "
            "Guests membership (%s)\n",
            nt_errstr(status)));
        /*
         * This is a hard error.
         */
        return status;
      }
    } else if (!NT_STATUS_IS_OK(status)) {
      DEBUG(2, ("Failed to create "
          "BUILTIN\\Guests group %s!  Can "
          "Winbind allocate gids?\n",
          nt_errstr(status)));
      /*
       * This is a hard error.
       */
      return status;
    }
  }

  TALLOC_FREE(info);

  /* Deal with local groups */

  if (lp_winbind_nested_groups()) {

    become_root();

    /* Now add the aliases. First the one from our local SAM */

    status = add_aliases(get_global_sam_sid(), result);

    if (!NT_STATUS_IS_OK(status)) {
      unbecome_root();
      return status;
    }

    /* Finally the builtin ones */

    status = add_aliases(&global_sid_Builtin, result);

    if (!NT_STATUS_IS_OK(status)) {
      unbecome_root();
      return status;
    }

    unbecome_root();
  }

  if (session_info_flags & AUTH_SESSION_INFO_NTLM) {
    struct dom_sid tmp_sid = { 0, };

    ok = dom_sid_parse(SID_NT_NTLM_AUTHENTICATION, &tmp_sid);
    if (!ok) {
      return NT_STATUS_NO_MEMORY;
    }

    status = add_sid_to_array(result,
            &tmp_sid,
            &result->sids,
            &result->num_sids);
    if (!NT_STATUS_IS_OK(status)) {
      return status;
    }
  }

  if (session_info_flags & AUTH_SESSION_INFO_SIMPLE_PRIVILEGES) {
    if (security_token_has_builtin_administrators(result)) {
      result->privilege_mask = ~0;
    }
  } else {
    /* Add privileges based on current user sids */
    get_privileges_for_sids(&result->privilege_mask, result->sids,
          result->num_sids);
  }

  return NT_STATUS_OK;
}

/****************************************************************************
 prints a UNIX 'token' to debug output.
****************************************************************************/

void debug_unix_user_token(int dbg_class, int dbg_lev, uid_t uid, gid_t gid,
         int n_groups, gid_t *groups)
{
  TALLOC_CTX *frame = NULL;
  char *s = NULL;
  int     i;

  if (!CHECK_DEBUGLVLC(dbg_class, dbg_lev)) {
    return;
  }

  frame = talloc_stackframe();

  s = talloc_asprintf(frame,
          "UNIX token of user %ld\n",
          (long int)uid);

  talloc_asprintf_addbuf(
    &s,
    "Primary group is %ld and contains %i supplementary "
    "groups\n",
    (long int)gid,
    n_groups);
  for (i = 0; i < n_groups; i++) {
    talloc_asprintf_addbuf(&s,
               "Group[%3i]: %ld\n",
               i,
               (long int)groups[i]);
  }

  DEBUGC(dbg_class, dbg_lev, ("%s", s ? s : "(NULL)"));
  TALLOC_FREE(frame);
}

/*
 * Create an artificial NT token given just a domain SID.
 *
 * We have 3 cases:
 *
 * unmapped unix users: Go directly to nss to find the user's group.
 *
 * A passdb user: The list of groups is provided by pdb_enum_group_memberships.
 *
 * If the user is provided by winbind, the primary gid is set to "domain
 * users" of the user's domain. For an explanation why this is necessary, see
 * the thread starting at
 * http://lists.samba.org/archive/samba-technical/2006-January/044803.html.
 */

static NTSTATUS create_token_from_sid(TALLOC_CTX *mem_ctx,
              const struct dom_sid *user_sid,
              bool is_guest,
              uid_t *uid, gid_t *gid,
              char **found_username,
              struct security_token **token)
{
  NTSTATUS result = NT_STATUS_NO_SUCH_USER;
  TALLOC_CTX *tmp_ctx = talloc_stackframe();
  gid_t *gids;
  struct dom_sid *group_sids;
  struct dom_sid tmp_sid;
  uint32_t num_group_sids;
  uint32_t num_gids;
  uint32_t i;
  uint32_t high, low;
  bool range_ok;
  struct dom_sid_buf buf;

  if (sid_check_is_in_our_sam(user_sid)) {
    bool ret;
    uint32_t pdb_num_group_sids;
    /* This is a passdb user, so ask passdb */

    struct samu *sam_acct = NULL;

    if ( !(sam_acct = samu_new( tmp_ctx )) ) {
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }

    become_root();
    ret = pdb_getsampwsid(sam_acct, user_sid);
    unbecome_root();

    if (!ret) {
      DEBUG(1, ("pdb_getsampwsid(%s) failed\n",
          dom_sid_str_buf(user_sid, &buf)));
      DEBUGADD(1, ("Fall back to unix user\n"));
      goto unix_user;
    }

    result = pdb_enum_group_memberships(tmp_ctx, sam_acct,
                &group_sids, &gids,
                &pdb_num_group_sids);
    if (!NT_STATUS_IS_OK(result)) {
      DEBUG(1, ("enum_group_memberships failed for %s: "
          "%s\n",
          dom_sid_str_buf(user_sid, &buf),
          nt_errstr(result)));
      DEBUGADD(1, ("Fall back to unix uid lookup\n"));
      goto unix_user;
    }
    num_group_sids = pdb_num_group_sids;

    /* see the smb_panic() in pdb_default_enum_group_memberships */
    SMB_ASSERT(num_group_sids > 0);

    /* Ensure we're returning the found_username on the right context. */
    *found_username = talloc_strdup(mem_ctx,
            pdb_get_username(sam_acct));

    if (*found_username == NULL) {
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }

    /*
     * If the SID from lookup_name() was the guest sid, passdb knows
     * about the mapping of guest sid to lp_guest_account()
     * username and will return the unix_pw info for a guest
     * user. Use it if it's there, else lookup the *uid details
     * using Get_Pwnam_alloc(). See bug #6291 for details. JRA.
     */

    /* We must always assign the *uid. */
    if (sam_acct->unix_pw == NULL) {
      struct passwd *pwd = Get_Pwnam_alloc(sam_acct, *found_username );
      if (!pwd) {
        DEBUG(10, ("Get_Pwnam_alloc failed for %s\n",
          *found_username));
        result = NT_STATUS_NO_SUCH_USER;
        goto done;
      }
      result = samu_set_unix(sam_acct, pwd );
      if (!NT_STATUS_IS_OK(result)) {
        DEBUG(10, ("samu_set_unix failed for %s\n",
          *found_username));
        result = NT_STATUS_NO_SUCH_USER;
        goto done;
      }
    }
    *uid = sam_acct->unix_pw->pw_uid;

  } else  if (sid_check_is_in_unix_users(user_sid)) {
    uint32_t getgroups_num_group_sids;
    /* This is a unix user not in passdb. We need to ask nss
     * directly, without consulting passdb */

    struct passwd *pass;

    /*
     * This goto target is used as a fallback for the passdb
     * case. The concrete bug report is when passdb gave us an
     * unmapped gid.
     */

  unix_user:

    if (!sid_to_uid(user_sid, uid)) {
      DEBUG(1, ("unix_user case, sid_to_uid for %s failed\n",
          dom_sid_str_buf(user_sid, &buf)));
      result = NT_STATUS_NO_SUCH_USER;
      goto done;
    }

    uid_to_unix_users_sid(*uid, &tmp_sid);
    user_sid = &tmp_sid;

    pass = getpwuid_alloc(tmp_ctx, *uid);
    if (pass == NULL) {
      DEBUG(1, ("getpwuid(%u) failed\n",
          (unsigned int)*uid));
      goto done;
    }

    if (!getgroups_unix_user(tmp_ctx, pass->pw_name, pass->pw_gid,
           &gids, &getgroups_num_group_sids)) {
      DEBUG(1, ("getgroups_unix_user for user %s failed\n",
          pass->pw_name));
      goto done;
    }
    num_group_sids = getgroups_num_group_sids;

    group_sids = talloc_array(tmp_ctx, struct dom_sid, num_group_sids);
    if (group_sids == NULL) {
      DEBUG(1, ("talloc_array failed\n"));
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }

    for (i=0; i<num_group_sids; i++) {
      gid_to_sid(&group_sids[i], gids[i]);
    }

    /* In getgroups_unix_user we always set the primary gid */
    SMB_ASSERT(num_group_sids > 0);

    /* Ensure we're returning the found_username on the right context. */
    *found_username = talloc_strdup(mem_ctx, pass->pw_name);
    if (*found_username == NULL) {
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }
  } else {

    /* This user is from winbind, force the primary gid to the
     * user's "domain users" group. Under certain circumstances
     * (user comes from NT4), this might be a loss of
     * information. But we can not rely on winbind getting the
     * correct info. AD might prohibit winbind looking up that
     * information. */

    /* We must always assign the *uid. */
    if (!sid_to_uid(user_sid, uid)) {
      DEBUG(1, ("winbindd case, sid_to_uid for %s failed\n",
          dom_sid_str_buf(user_sid, &buf)));
      result = NT_STATUS_NO_SUCH_USER;
      goto done;
    }

    num_group_sids = 1;
    group_sids = talloc_array(tmp_ctx, struct dom_sid, num_group_sids);
    if (group_sids == NULL) {
      DEBUG(1, ("talloc_array failed\n"));
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }

    gids = talloc_array(tmp_ctx, gid_t, num_group_sids);
    if (gids == NULL) {
      result = NT_STATUS_NO_MEMORY;
      goto done;
    }

    sid_copy(&group_sids[0], user_sid);
    sid_split_rid(&group_sids[0], NULL);
    sid_append_rid(&group_sids[0], DOMAIN_RID_USERS);

    if (!sid_to_gid(&group_sids[0], &gids[0])) {
      DEBUG(1, ("sid_to_gid(%s) failed\n",
          dom_sid_str_buf(&group_sids[0], &buf)));
      goto done;
    }

    *found_username = NULL;
  }

  *gid = gids[0];

  /* Add the "Unix Group" SID for each gid to catch mapped groups
     and their Unix equivalent.  This is to solve the backwards
     compatibility problem of 'valid users = +ntadmin' where
     ntadmin has been paired with "Domain Admins" in the group
     mapping table.  Otherwise smb.conf would need to be changed
     to 'valid user = "Domain Admins"'.  --jerry */

  num_gids = num_group_sids;
  range_ok = lp_idmap_default_range(&low, &high);
  for ( i=0; i<num_gids; i++ ) {
    struct dom_sid unix_group_sid;

    /* don't pickup anything managed by Winbind */
    if (range_ok && (gids[i] >= low) && (gids[i] <= high)) {
      continue;
    }

    gid_to_unix_groups_sid(gids[i], &unix_group_sid);

    result = add_sid_to_array_unique(tmp_ctx, &unix_group_sid,
             &group_sids, &num_group_sids);
    if (!NT_STATUS_IS_OK(result)) {
      goto done;
    }
  }

  /* Ensure we're creating the nt_token on the right context. */
  result = create_local_nt_token(mem_ctx, user_sid,
               is_guest, num_group_sids, group_sids, token);

  if (!NT_STATUS_IS_OK(result)) {
    goto done;
  }

  result = NT_STATUS_OK;
 done:
  TALLOC_FREE(tmp_ctx);
  return result;
}

/*
 * Create an artificial NT token given just a username. (Initially intended
 * for force user)
 *
 * We go through lookup_name() to avoid problems we had with 'winbind use
 * default domain'.
 *
 * We have 3 cases:
 *
 * unmapped unix users: Go directly to nss to find the user's group.
 *
 * A passdb user: The list of groups is provided by pdb_enum_group_memberships.
 *
 * If the user is provided by winbind, the primary gid is set to "domain
 * users" of the user's domain. For an explanation why this is necessary, see
 * the thread starting at
 * http://lists.samba.org/archive/samba-technical/2006-January/044803.html.
 */

NTSTATUS create_token_from_username(TALLOC_CTX *mem_ctx, const char *username,
            bool is_guest,
            uid_t *uid, gid_t *gid,
            char **found_username,
            struct security_token **token)
{
  NTSTATUS result = NT_STATUS_NO_SUCH_USER;
  TALLOC_CTX *tmp_ctx = talloc_stackframe();
  struct dom_sid user_sid;
  enum lsa_SidType type;

  if (!lookup_name_smbconf(tmp_ctx, username, LOOKUP_NAME_ALL,
       NULL, NULL, &user_sid, &type)) {
    DEBUG(1, ("lookup_name_smbconf for %s failed\n", username));
    goto done;
  }

  if (type != SID_NAME_USER) {
    DEBUG(1, ("%s is a %s, not a user\n", username,
        sid_type_lookup(type)));
    goto done;
  }

  result = create_token_from_sid(mem_ctx, &user_sid, is_guest, uid, gid, found_username, token);

  if (!NT_STATUS_IS_OK(result)) {
    goto done;
  }

  /*
   * If result == NT_STATUS_OK then
   * we know we have a valid token. Ensure
   * we also have a valid username to match.
   */

  if (*found_username == NULL) {
    *found_username = talloc_strdup(mem_ctx, username);
    if (*found_username == NULL) {
      result = NT_STATUS_NO_MEMORY;
    }
  }

done:
  TALLOC_FREE(tmp_ctx);
  return result;
}

/***************************************************************************
 Build upon create_token_from_sid:

 Expensive helper function to figure out whether a user given its sid is
 member of a particular group.
***************************************************************************/

bool user_sid_in_group_sid(const struct dom_sid *sid, const struct dom_sid *group_sid)
{
  NTSTATUS status;
  uid_t uid;
  gid_t gid;
  char *found_username;
  struct security_token *token;
  bool result = false;
  enum lsa_SidType type;
  TALLOC_CTX *mem_ctx = talloc_stackframe();
  struct dom_sid_buf buf;

  if (!lookup_sid(mem_ctx, sid,
       NULL, NULL, &type)) {
    DEBUG(1, ("lookup_sid for %s failed\n",
        dom_sid_str_buf(sid, &buf)));
    goto done;
  }

  if (type != SID_NAME_USER) {
    DEBUG(5, ("%s is a %s, not a user\n",
        dom_sid_str_buf(sid, &buf),
        sid_type_lookup(type)));
    goto done;
  }

  status = create_token_from_sid(mem_ctx, sid, False,
               &uid, &gid, &found_username,
               &token);

  if (!NT_STATUS_IS_OK(status)) {
    DEBUG(10, ("could not create token for %s\n",
         dom_sid_str_buf(sid, &buf)));
    goto done;
  }

  result = security_token_has_sid(token, group_sid);

done:
  TALLOC_FREE(mem_ctx);
  return result;
}

/***************************************************************************
 Build upon create_token_from_username:

 Expensive helper function to figure out whether a user given its name is
 member of a particular group.
***************************************************************************/

bool user_in_group_sid(const char *username, const struct dom_sid *group_sid)
{
  NTSTATUS status;
  uid_t uid;
  gid_t gid;
  char *found_username;
  struct security_token *token;
  bool result;
  TALLOC_CTX *mem_ctx = talloc_stackframe();

  status = create_token_from_username(mem_ctx, username, False,
              &uid, &gid, &found_username,
              &token);

  if (!NT_STATUS_IS_OK(status)) {
    DEBUG(10, ("could not create token for %s\n", username));
    TALLOC_FREE(mem_ctx);
    return False;
  }

  result = security_token_has_sid(token, group_sid);

  TALLOC_FREE(mem_ctx);
  return result;
}

bool user_in_group(const char *username, const char *groupname)
{
  TALLOC_CTX *mem_ctx = talloc_stackframe();
  struct dom_sid group_sid;
  bool ret;

  ret = lookup_name(mem_ctx, groupname, LOOKUP_NAME_ALL,
        NULL, NULL, &group_sid, NULL);
  TALLOC_FREE(mem_ctx);

  if (!ret) {
    DEBUG(10, ("lookup_name for (%s) failed.\n", groupname));
    return False;
  }

  return user_in_group_sid(username, &group_sid);
}

/* END */

Coverage Report

Created: 2025-07-23 07:04