SQLite

   );

With this extension, a database can be marked as requiring authentication.
By default a database does not require authentication.

The sqlite3_open(), sqlite3_open16(), and sqlite3_open_v2() interfaces
work as before: they open a new database connection.  However, if the
database being opened requires authentication, then attempts to read

or write from the database will fail with an SQLITE_AUTH error until 
after sqlite3_user_authenticate() has been called successfully.  The 
sqlite3_user_authenticate() call will return SQLITE_OK if the 
authentication credentials are accepted and SQLITE_ERROR if not.

Calling sqlite3_user_authenticate() on a no-authentication-required
database connection is a harmless no-op.  

If the database is encrypted, then sqlite3_key_v2() must be called first,
with the correct decryption key, prior to invoking sqlite3_user_authenticate().

    CREATE TABLE sqlite_user(
      uname TEXT PRIMARY KEY,
      isAdmin BOOLEAN,
      pw BLOB
    ) WITHOUT ROWID;

The sqlite_user table is inaccessible (unreadable and unwriteable) to
non-admin users and is read-only for admin users.  However, if the same
database file is opened by a version of SQLite that omits
the -DSQLITE_USER_AUTHENTICATION compile-time option, then the sqlite_user
table will be readable by anybody and writeable by anybody if
the "PRAGMA writable_schema=ON" statement is run first.

The sqlite_user.pw field is encoded by a built-in SQL function
"sqlite_crypt(X,Y)".  The two arguments are both BLOBs.  The first argument
is the plaintext password supplied to the sqlite3_user_authenticate()
interface.  The second argument is the sqlite_user.pw value and is supplied
so that the function can extract the "salt" used by the password encoder.
The result of sqlite_crypt(X,Y) is another blob which is the value that

  sqlite3 *db,           /* Database connection */
  const char *zUsername, /* Username to change */
  const char *aPW,       /* Modified password or credentials */
  int nPW,               /* Number of bytes in aPW[] */
  int isAdmin            /* Modified admin privilege for the user */
){
  sqlite3_stmt *pStmt;
  int rc;
  u8 authLevel;

  authLevel = db->auth.authLevel;
  if( authLevel<UAUTH_User ){
    /* Must be logged in to make a change */
    return SQLITE_AUTH;
  }
  if( strcmp(db->auth.zAuthUser, zUsername)!=0 ){
    if( db->auth.authLevel<UAUTH_Admin ){
      /* Must be an administrator to change a different user */
      return SQLITE_AUTH;
    }
  }else if( isAdmin!=(authLevel==UAUTH_Admin) ){
    /* Cannot change the isAdmin setting for self */
    return SQLITE_AUTH;
  }
  db->auth.authLevel = UAUTH_Admin;
  if( !userTableExists(db, "main") ){
    /* This routine is a no-op if the user to be modified does not exist */

  }else{
  pStmt = sqlite3UserAuthPrepare(db,
            "UPDATE sqlite_user SET isAdmin=%d, pw=sqlite_crypt(?1,NULL)"
            " WHERE uname=%Q", isAdmin, zUsername);
    if( pStmt==0 ){
      rc = SQLITE_NOMEM;
    }else{
  sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
  sqlite3_step(pStmt);
      rc = sqlite3_finalize(pStmt);
    }
  }
  db->auth.authLevel = authLevel;
  return rc;
}

/*
** The sqlite3_user_delete() interface can be used (by an admin user only)
** to delete a user.  The currently logged-in user cannot be deleted,
** which guarantees that there is always an admin user and hence that
** the database cannot be converted into a no-authentication-required

do_test userauth01-1.5 {
  execsql {
    SELECT quote(x) FROM t1 ORDER BY x;
    SELECT uname, isadmin FROM sqlite_user ORDER BY uname;
    SELECT name FROM sqlite_master ORDER BY name;
  }
} {NULL 1 2.5 'three' X'4444' alice 1 sqlite_user t1}

# The sqlite3_user_add() interface can be used (by an admin user only)
# to create a new user.
#
do_test userauth01-1.6 {
  sqlite3_user_add db bob pw-4-bob 0
  sqlite3_user_add db cindy pw-4-cindy 0
  sqlite3_user_add db david pw-4-david 0
  execsql {
    SELECT uname, isadmin FROM sqlite_user ORDER BY uname;
  }
} {alice 1 bob 0 cindy 0 david 0}

# The sqlite_user table is inaccessible (unreadable and unwriteable) to
# non-admin users and is read-only for admin users.  However, if the same
#
do_test userauth01-1.7 {
  sqlite3 db2 test.db
  sqlite3_user_authenticate db2 cindy pw-4-cindy
  db2 eval {
    SELECT quote(x) FROM t1 ORDER BY x;
    SELECT name FROM sqlite_master ORDER BY name;
  }
} {NULL 1 2.5 'three' X'4444' sqlite_user t1}
do_test userauth01-1.8 {
  catchsql {
    SELECT uname, isadmin FROM sqlite_user ORDER BY uname;
  } db2
} {1 {no such table: sqlite_user}}

# Any user can change their own password.  
#
do_test userauth01-1.9 {
  sqlite3_user_change db2 cindy xyzzy-cindy 0
} {SQLITE_OK}
do_test userauth01-1.10 {
  sqlite3_user_authenticate db2 cindy pw-4-cindy
} {SQLITE_AUTH}
do_test userauth01-1.11 {
  sqlite3_user_authenticate db2 cindy xyzzy-cindy
} {SQLITE_OK}



finish_test