/*

 *  Unix SMB/Netbios implementation.

 *  SEC_DESC handling functions

 *  Copyright (C) Jeremy R. Allison            1995-2003.

 *

 *  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/>.

 */

#include "includes.h"

#include "system/filesys.h"

#include "../libcli/security/security.h"

#include "../librpc/gen_ndr/ndr_security.h"

#include "dbwrap/dbwrap.h"

#include "dbwrap/dbwrap_open.h"

#include "util_tdb.h"

#include "libcli/util/ntstatus.h"

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

 Create the share security tdb.

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

static struct db_context *share_db; /* used for share security descriptors */

#define SHARE_DATABASE_VERSION_V1 1

#define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */

#define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */

#define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"

/* Map generic permissions to file object specific permissions */

extern const struct generic_mapping file_generic_mapping;

static int delete_fn(struct db_record *rec, void *priv)

{

  dbwrap_record_delete(rec);

  return 0;

}

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

 Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".

 If we find one re-write it into a canonical case form.

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

static int upgrade_v2_to_v3(struct db_record *rec, void *priv)

{

  size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);

  const char *servicename = NULL;

  char *c_servicename = NULL;

  char *newkey = NULL;

  bool *p_upgrade_ok = (bool *)priv;

  NTSTATUS status;

  TDB_DATA key;

  TDB_DATA value;

  key = dbwrap_record_get_key(rec);

  /* Is there space for a one character sharename ? */

  if (key.dsize <= prefix_len+2) {

    return 0;

  }

  /* Does it start with the share key prefix ? */

  if (memcmp(key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,

      prefix_len) != 0) {

    return 0;

  }

  /* Is it a null terminated string as a key ? */

  if (key.dptr[key.dsize-1] != '\0') {

    return 0;

  }

  /* Bytes after the prefix are the sharename string. */

  servicename = (char *)&key.dptr[prefix_len];

  c_servicename = canonicalize_servicename(talloc_tos(), servicename);

  if (!c_servicename) {

    smb_panic("out of memory upgrading share security db from v2 -> v3");

  }

  if (strcmp(servicename, c_servicename) == 0) {

    /* Old and new names match. No canonicalization needed. */

    TALLOC_FREE(c_servicename);

    return 0;

  }

  /* Oops. Need to canonicalize name, delete old then store new. */

  status = dbwrap_record_delete(rec);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "

        "%s: %s\n", (const char *)key.dptr,

        nt_errstr(status)));

    TALLOC_FREE(c_servicename);

    *p_upgrade_ok = false;

    return -1;

  } else {

    DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "

                          "%s\n", (const char *)key.dptr));

  }

  if (!(newkey = talloc_asprintf(talloc_tos(),

      SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",

      c_servicename))) {

    smb_panic("out of memory upgrading share security db from v2 -> v3");

  }

  value = dbwrap_record_get_value(rec);

  status = dbwrap_store(share_db,

        string_term_tdb_data(newkey),

        value,

        TDB_REPLACE);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "

        "%s: %s\n", c_servicename, nt_errstr(status)));

    TALLOC_FREE(c_servicename);

    TALLOC_FREE(newkey);

    *p_upgrade_ok = false;

    return -1;

  } else {

    DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "

                          "%s\n", newkey ));

  }

  TALLOC_FREE(newkey);

  TALLOC_FREE(c_servicename);

  return 0;

}

NTSTATUS share_info_db_init(void)

{

  const char *vstring = "INFO/version";

  int32_t vers_id = 0;

  bool upgrade_ok = true;

  NTSTATUS status;

  char *db_path;

  if (share_db != NULL) {

    return NT_STATUS_OK;

  }

  db_path = state_path(talloc_tos(), "share_info.tdb");

  if (db_path == NULL) {

    return NT_STATUS_NO_MEMORY;

  }

  share_db = db_open(NULL, db_path, 0,

         TDB_DEFAULT, O_RDWR|O_CREAT, 0600,

         DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);

  if (share_db == NULL) {

    DEBUG(0,("Failed to open share info database %s (%s)\n",

       db_path, strerror(errno)));

    TALLOC_FREE(db_path);

    return map_nt_error_from_unix_common(errno);

  }

  TALLOC_FREE(db_path);

  status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);

  if (!NT_STATUS_IS_OK(status)) {

    vers_id = 0;

  }

  if (vers_id == SHARE_DATABASE_VERSION_V3) {

    return NT_STATUS_OK;

  }

  if (dbwrap_transaction_start(share_db) != 0) {

    DEBUG(0, ("transaction_start failed\n"));

    TALLOC_FREE(share_db);

    return NT_STATUS_INTERNAL_DB_ERROR;

  }

  status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);

  if (!NT_STATUS_IS_OK(status)) {

    vers_id = 0;

  }

  if (vers_id == SHARE_DATABASE_VERSION_V3) {

    /*

     * Race condition

     */

    if (dbwrap_transaction_cancel(share_db)) {

      smb_panic("transaction_cancel failed");

    }

    return NT_STATUS_OK;

  }

  /* Move to at least V2. */

  /* Cope with byte-reversed older versions of the db. */

  if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {

    /* Written on a bigendian machine with old fetch_int code. Save as le. */

    status = dbwrap_store_int32_bystring(

      share_db, vstring, SHARE_DATABASE_VERSION_V2);

    if (!NT_STATUS_IS_OK(status)) {

      DEBUG(0, ("dbwrap_store_int32 failed: %s\n",

          nt_errstr(status)));

      goto cancel;

    }

    vers_id = SHARE_DATABASE_VERSION_V2;

  }

  if (vers_id != SHARE_DATABASE_VERSION_V2) {

    status = dbwrap_traverse(share_db, delete_fn, NULL, NULL);

    if (!NT_STATUS_IS_OK(status)) {

      DEBUG(0, ("traverse failed\n"));

      goto cancel;

    }

    status = dbwrap_store_int32_bystring(

      share_db, vstring, SHARE_DATABASE_VERSION_V2);

    if (!NT_STATUS_IS_OK(status)) {

      DEBUG(0, ("dbwrap_store_int32 failed: %s\n",

          nt_errstr(status)));

      goto cancel;

    }

  }

  /* Finally upgrade to version 3, with canonicalized sharenames. */

  status = dbwrap_traverse(share_db, upgrade_v2_to_v3, &upgrade_ok, NULL);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(0, ("traverse failed\n"));

    goto cancel;

  }

  if (!upgrade_ok) {

    DBG_ERR("upgrade failed.\n");

    status = NT_STATUS_INTERNAL_ERROR;

    goto cancel;

  }

  status = dbwrap_store_int32_bystring(

    share_db, vstring, SHARE_DATABASE_VERSION_V3);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(0, ("dbwrap_store_int32 failed: %s\n",

        nt_errstr(status)));

    goto cancel;

  }

  if (dbwrap_transaction_commit(share_db) != 0) {

    DEBUG(0, ("transaction_commit failed\n"));

    return NT_STATUS_INTERNAL_ERROR;

  }

  return NT_STATUS_OK;

 cancel:

  if (dbwrap_transaction_cancel(share_db)) {

    smb_panic("transaction_cancel failed");

  }

  return status;

}

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

 Fake up a Everyone, default access as a default.

 def_access is a GENERIC_XXX access mode.

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

static struct security_descriptor *get_share_security_default(TALLOC_CTX *ctx,

              size_t *psize,

              uint32_t def_access)

{

  uint32_t sa;

  struct security_ace ace = {

    .size = 0,

  };

  struct security_acl *psa = NULL;

  struct security_descriptor *psd = NULL;

  uint32_t spec_access = def_access;

  se_map_generic(&spec_access, &file_generic_mapping);

  sa = (def_access | spec_access );

  init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);

  if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {

    psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,

            SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,

            psa, psize);

  }

  if (!psd) {

    DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));

    return NULL;

  }

  return psd;

}

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

 Pull a security descriptor from the share tdb.

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

struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,

            size_t *psize)

{

  char *key;

  struct security_descriptor *psd = NULL;

  TDB_DATA data;

  char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);

  NTSTATUS status;

  if (!c_servicename) {

    return NULL;

  }

  status = share_info_db_init();

  if (!NT_STATUS_IS_OK(status)) {

    TALLOC_FREE(c_servicename);

    return NULL;

  }

  if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {

    TALLOC_FREE(c_servicename);

    DEBUG(0, ("talloc_asprintf failed\n"));

    return NULL;

  }

  TALLOC_FREE(c_servicename);

  status = dbwrap_fetch_bystring(share_db, talloc_tos(), key, &data);

  TALLOC_FREE(key);

  if (!NT_STATUS_IS_OK(status)) {

    return get_share_security_default(ctx, psize,

              SEC_RIGHTS_DIR_ALL);

  }

  status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);

  TALLOC_FREE(data.dptr);

  if (!NT_STATUS_IS_OK(status)) {

    return get_share_security_default(ctx, psize,

              SEC_RIGHTS_DIR_ALL);

  }

  if (psd) {

    *psize = ndr_size_security_descriptor(psd, 0);

  } else {

    return get_share_security_default(ctx, psize,

              SEC_RIGHTS_DIR_ALL);

  }

  return psd;

}

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

 Store a security descriptor in the share db.

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

NTSTATUS set_share_security(const char *share_name,

          struct security_descriptor *psd)

{

  TALLOC_CTX *frame = talloc_stackframe();

  char *key;

  TDB_DATA blob;

  NTSTATUS status;

  char *c_share_name = canonicalize_servicename(frame, share_name);

  if (c_share_name == NULL) {

    status = NT_STATUS_INVALID_PARAMETER;

    goto out;

  }

  status = share_info_db_init();

  if (!NT_STATUS_IS_OK(status)) {

    goto out;

  }

  status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(0, ("marshall_sec_desc failed: %s\n",

        nt_errstr(status)));

    goto out;

  }

  if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {

    DEBUG(0, ("talloc_asprintf failed\n"));

    status = NT_STATUS_NO_MEMORY;

    goto out;

  }

  status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,

            TDB_REPLACE);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(1, ("set_share_security: Failed to store secdesc for "

        "%s: %s\n", share_name, nt_errstr(status)));

    goto out;

  }

  DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));

  status = NT_STATUS_OK;

 out:

  TALLOC_FREE(frame);

  return status;

}

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

 Delete a security descriptor.

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

NTSTATUS delete_share_security(const char *servicename)

{

  TDB_DATA kbuf;

  char *key;

  NTSTATUS status;

  char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);

  if (c_servicename == NULL) {

    return NT_STATUS_INVALID_PARAMETER;

  }

  status = share_info_db_init();

  if (!NT_STATUS_IS_OK(status)) {

    TALLOC_FREE(c_servicename);

    return status;

  }

  if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",

            c_servicename))) {

    TALLOC_FREE(c_servicename);

    return NT_STATUS_NO_MEMORY;

  }

  kbuf = string_term_tdb_data(key);

  status = dbwrap_trans_delete(share_db, kbuf);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(0, ("delete_share_security: Failed to delete entry for "

        "share %s: %s\n", c_servicename, nt_errstr(status)));

    TALLOC_FREE(c_servicename);

    return status;

  }

  TALLOC_FREE(c_servicename);

  return NT_STATUS_OK;

}

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

 Can this user access with share with the required permissions ?

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

bool share_access_check(const struct security_token *token,

      const char *sharename,

      uint32_t desired_access,

      uint32_t *pgranted)

{

  uint32_t granted;

  NTSTATUS status;

  struct security_descriptor *psd = NULL;

  size_t sd_size;

  psd = get_share_security(talloc_tos(), sharename, &sd_size);

  if (!psd) {

    if (pgranted != NULL) {

      *pgranted = desired_access;

    }

    return false;

  }

  status = se_file_access_check(psd, token, true, desired_access, &granted);

  TALLOC_FREE(psd);

  if (pgranted != NULL) {

    *pgranted = granted;

  }

  return NT_STATUS_IS_OK(status);

}

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

 Parse the contents of an acl string from a usershare file.

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

bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)

{

  size_t s_size = 0;

  const char *pacl = acl_str;

  int num_aces = 0;

  struct security_ace *ace_list = NULL;

  struct security_acl *psa = NULL;

  struct security_descriptor *psd = NULL;

  size_t sd_size = 0;

  int i;

  *ppsd = NULL;

  /* If the acl string is blank return "Everyone:R" */

  if (!*acl_str) {

    struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);

    if (!default_psd) {

      return False;

    }

    *ppsd = default_psd;

    return True;

  }

  num_aces = 1;

  /* Add the number of ',' characters to get the number of aces. */

  num_aces += count_chars(pacl,',');

  ace_list = talloc_array(ctx, struct security_ace, num_aces);

  if (!ace_list) {

    return False;

  }

  for (i = 0; i < num_aces; i++) {

    uint32_t sa;

    uint32_t g_access;

    uint32_t s_access;

    struct dom_sid sid;

    char *sidstr;

    enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;

    if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {

      DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "

        "for ':' in string '%s'\n", pacl));

      return False;

    }

    if (!string_to_sid(&sid, sidstr)) {

      DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",

        sidstr ));

      return False;

    }

    switch (*pacl) {

      case 'F': /* Full Control, ie. R+W */

      case 'f': /* Full Control, ie. R+W */

        s_access = g_access = GENERIC_ALL_ACCESS;

        break;

      case 'R': /* Read only. */

      case 'r': /* Read only. */

        s_access = g_access = GENERIC_READ_ACCESS;

        break;

      case 'D': /* Deny all to this SID. */

      case 'd': /* Deny all to this SID. */

        type = SEC_ACE_TYPE_ACCESS_DENIED;

        s_access = g_access = GENERIC_ALL_ACCESS;

        break;

      default:

        DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",

          pacl ));

        return False;

    }

    pacl++;

    if (*pacl && *pacl != ',') {

      DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",

        pacl ));

      return False;

    }

    pacl++; /* Go past any ',' */

    se_map_generic(&s_access, &file_generic_mapping);

    sa = (g_access | s_access);

    init_sec_ace(&ace_list[i], &sid, type, sa, 0);

  }

  if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {

    psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,

            SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,

            psa, &sd_size);

  }

  if (!psd) {

    DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));

    return False;

  }

  *ppsd = psd;

  return True;

}