ADD: User authentication

* User Authentication Implementation
* Rename file to conform to fileformat `sqlite3_*_omit.go`
* Updated sqlite3-binding.* with new upgrade tool
* Add: callbackRetNil required for error type return because of adding `RegisterFunc`s directly on the connection.
* Add: TestCreateAuthDatabase

Author: gjrtimmer

Diff for: callback.go

@@ -331,8 +331,18 @@ func callbackRetText(ctx *C.sqlite3_context, v reflect.Value) error {
 	return nil
 }
 
+func callbackRetNil(ctx *C.sqlite3_context, v reflect.Value) error {
+	return nil
+}
+
 func callbackRet(typ reflect.Type) (callbackRetConverter, error) {
 	switch typ.Kind() {
+	case reflect.Interface:
+		errorInterface := reflect.TypeOf((*error)(nil)).Elem()
+		if typ.Implements(errorInterface) {
+			return callbackRetNil, nil
+		}
+		fallthrough
 	case reflect.Slice:
 		if typ.Elem().Kind() != reflect.Uint8 {
 			return nil, errors.New("the only supported slice type is []byte")

Diff for: sqlite3-binding.c

@@ -209943,4 +209943,359 @@ SQLITE_API const char *sqlite3_sourceid(void){ return SQLITE_SOURCE_ID; }
 #else // USE_LIBSQLITE3
  // If users really want to link against the system sqlite3 we
 // need to make this file a noop.
- #endif
+ #endif
+/*
+** 2014-09-08
+**
+** The author disclaims copyright to this source code.  In place of
+** a legal notice, here is a blessing:
+**
+**    May you do good and not evil.
+**    May you find forgiveness for yourself and forgive others.
+**    May you share freely, never taking more than you give.
+**
+*************************************************************************
+**
+** This file contains the bulk of the implementation of the
+** user-authentication extension feature.  Some parts of the user-
+** authentication code are contained within the SQLite core (in the
+** src/ subdirectory of the main source code tree) but those parts
+** that could reasonable be separated out are moved into this file.
+**
+** To compile with the user-authentication feature, append this file to
+** end of an SQLite amalgamation, then add the SQLITE_USER_AUTHENTICATION
+** compile-time option.  See the user-auth.txt file in the same source
+** directory as this file for additional information.
+*/
+#ifdef SQLITE_USER_AUTHENTICATION
+#ifndef SQLITEINT_H
+# include "sqliteInt.h"
+#endif
+
+/*
+** Prepare an SQL statement for use by the user authentication logic.
+** Return a pointer to the prepared statement on success.  Return a
+** NULL pointer if there is an error of any kind.
+*/
+static sqlite3_stmt *sqlite3UserAuthPrepare(
+  sqlite3 *db,
+  const char *zFormat,
+  ...
+){
+  sqlite3_stmt *pStmt;
+  char *zSql;
+  int rc;
+  va_list ap;
+  int savedFlags = db->flags;
+
+  va_start(ap, zFormat);
+  zSql = sqlite3_vmprintf(zFormat, ap);
+  va_end(ap);
+  if( zSql==0 ) return 0;
+  db->flags |= SQLITE_WriteSchema;
+  rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0);
+  db->flags = savedFlags;
+  sqlite3_free(zSql);
+  if( rc ){
+    sqlite3_finalize(pStmt);
+    pStmt = 0;
+  }
+  return pStmt;
+}
+
+/*
+** Check to see if the sqlite_user table exists in database zDb.
+*/
+static int userTableExists(sqlite3 *db, const char *zDb){
+  int rc;
+  sqlite3_mutex_enter(db->mutex);
+  sqlite3BtreeEnterAll(db);
+  if( db->init.busy==0 ){
+    char *zErr = 0;
+    sqlite3Init(db, &zErr);
+    sqlite3DbFree(db, zErr);
+  }
+  rc = sqlite3FindTable(db, "sqlite_user", zDb)!=0;
+  sqlite3BtreeLeaveAll(db);
+  sqlite3_mutex_leave(db->mutex);
+  return rc;
+}
+
+/*
+** Check to see if database zDb has a "sqlite_user" table and if it does
+** whether that table can authenticate zUser with nPw,zPw.  Write one of
+** the UAUTH_* user authorization level codes into *peAuth and return a
+** result code.
+*/
+static int userAuthCheckLogin(
+  sqlite3 *db,               /* The database connection to check */
+  const char *zDb,           /* Name of specific database to check */
+  u8 *peAuth                 /* OUT: One of UAUTH_* constants */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+
+  *peAuth = UAUTH_Unknown;
+  if( !userTableExists(db, "main") ){
+    *peAuth = UAUTH_Admin;  /* No sqlite_user table.  Everybody is admin. */
+    return SQLITE_OK;
+  }
+  if( db->auth.zAuthUser==0 ){
+    *peAuth = UAUTH_Fail;
+    return SQLITE_OK;
+  }
+  pStmt = sqlite3UserAuthPrepare(db,
+            "SELECT pw=sqlite_crypt(?1,pw), isAdmin FROM \"%w\".sqlite_user"
+            " WHERE uname=?2", zDb);
+  if( pStmt==0 ) return SQLITE_NOMEM;
+  sqlite3_bind_blob(pStmt, 1, db->auth.zAuthPW, db->auth.nAuthPW,SQLITE_STATIC);
+  sqlite3_bind_text(pStmt, 2, db->auth.zAuthUser, -1, SQLITE_STATIC);
+  rc = sqlite3_step(pStmt);
+  if( rc==SQLITE_ROW && sqlite3_column_int(pStmt,0) ){
+    *peAuth = sqlite3_column_int(pStmt, 1) + UAUTH_User;
+  }else{
+    *peAuth = UAUTH_Fail;
+  }
+  return sqlite3_finalize(pStmt);
+}
+int sqlite3UserAuthCheckLogin(
+  sqlite3 *db,               /* The database connection to check */
+  const char *zDb,           /* Name of specific database to check */
+  u8 *peAuth                 /* OUT: One of UAUTH_* constants */
+){
+  int rc;
+  u8 savedAuthLevel;
+  assert( zDb!=0 );
+  assert( peAuth!=0 );
+  savedAuthLevel = db->auth.authLevel;
+  db->auth.authLevel = UAUTH_Admin;
+  rc = userAuthCheckLogin(db, zDb, peAuth);
+  db->auth.authLevel = savedAuthLevel;
+  return rc;
+}
+
+/*
+** If the current authLevel is UAUTH_Unknown, the take actions to figure
+** out what authLevel should be
+*/
+void sqlite3UserAuthInit(sqlite3 *db){
+  if( db->auth.authLevel==UAUTH_Unknown ){
+    u8 authLevel = UAUTH_Fail;
+    sqlite3UserAuthCheckLogin(db, "main", &authLevel);
+    db->auth.authLevel = authLevel;
+    if( authLevel<UAUTH_Admin ) db->flags &= ~SQLITE_WriteSchema;
+  }
+}
+
+/*
+** Implementation of the sqlite_crypt(X,Y) function.
+**
+** If Y is NULL then generate a new hash for password X and return that
+** hash.  If Y is not null, then generate a hash for password X using the
+** same salt as the previous hash Y and return the new hash.
+*/
+void sqlite3CryptFunc(
+  sqlite3_context *context,
+  int NotUsed,
+  sqlite3_value **argv
+){
+  const char *zIn;
+  int nIn, ii;
+  u8 *zOut;
+  char zSalt[8];
+  zIn = sqlite3_value_blob(argv[0]);
+  nIn = sqlite3_value_bytes(argv[0]);
+  if( sqlite3_value_type(argv[1])==SQLITE_BLOB
+   && sqlite3_value_bytes(argv[1])==nIn+sizeof(zSalt)
+  ){
+    memcpy(zSalt, sqlite3_value_blob(argv[1]), sizeof(zSalt));
+  }else{
+    sqlite3_randomness(sizeof(zSalt), zSalt);
+  }
+  zOut = sqlite3_malloc( nIn+sizeof(zSalt) );
+  if( zOut==0 ){
+    sqlite3_result_error_nomem(context);
+  }else{
+    memcpy(zOut, zSalt, sizeof(zSalt));
+    for(ii=0; ii<nIn; ii++){
+      zOut[ii+sizeof(zSalt)] = zIn[ii]^zSalt[ii&0x7];
+    }
+    sqlite3_result_blob(context, zOut, nIn+sizeof(zSalt), sqlite3_free);
+  }
+}
+
+/*
+** If a database contains the SQLITE_USER table, then the
+** sqlite3_user_authenticate() interface must be invoked with an
+** appropriate username and password prior to enable read and write
+** access to the database.
+**
+** Return SQLITE_OK on success or SQLITE_ERROR if the username/password
+** combination is incorrect or unknown.
+**
+** If the SQLITE_USER table is not present in the database file, then
+** this interface is a harmless no-op returnning SQLITE_OK.
+*/
+int sqlite3_user_authenticate(
+  sqlite3 *db,           /* The database connection */
+  const char *zUsername, /* Username */
+  const char *zPW,       /* Password or credentials */
+  int nPW                /* Number of bytes in aPW[] */
+){
+  int rc;
+  u8 authLevel = UAUTH_Fail;
+  db->auth.authLevel = UAUTH_Unknown;
+  sqlite3_free(db->auth.zAuthUser);
+  sqlite3_free(db->auth.zAuthPW);
+  memset(&db->auth, 0, sizeof(db->auth));
+  db->auth.zAuthUser = sqlite3_mprintf("%s", zUsername);
+  if( db->auth.zAuthUser==0 ) return SQLITE_NOMEM;
+  db->auth.zAuthPW = sqlite3_malloc( nPW+1 );
+  if( db->auth.zAuthPW==0 ) return SQLITE_NOMEM;
+  memcpy(db->auth.zAuthPW,zPW,nPW);
+  db->auth.nAuthPW = nPW;
+  rc = sqlite3UserAuthCheckLogin(db, "main", &authLevel);
+  db->auth.authLevel = authLevel;
+  sqlite3ExpirePreparedStatements(db);
+  if( rc ){
+    return rc;           /* OOM error, I/O error, etc. */
+  }
+  if( authLevel<UAUTH_User ){
+    return SQLITE_AUTH;  /* Incorrect username and/or password */
+  }
+  return SQLITE_OK;      /* Successful login */
+}
+
+/*
+** The sqlite3_user_add() interface can be used (by an admin user only)
+** to create a new user.  When called on a no-authentication-required
+** database, this routine converts the database into an authentication-
+** required database, automatically makes the added user an
+** administrator, and logs in the current connection as that user.
+** The sqlite3_user_add() interface only works for the "main" database, not
+** for any ATTACH-ed databases.  Any call to sqlite3_user_add() by a
+** non-admin user results in an error.
+*/
+int sqlite3_user_add(
+  sqlite3 *db,           /* Database connection */
+  const char *zUsername, /* Username to be added */
+  const char *aPW,       /* Password or credentials */
+  int nPW,               /* Number of bytes in aPW[] */
+  int isAdmin            /* True to give new user admin privilege */
+){
+  sqlite3_stmt *pStmt;
+  int rc;
+  sqlite3UserAuthInit(db);
+  if( db->auth.authLevel<UAUTH_Admin ) return SQLITE_AUTH;
+  if( !userTableExists(db, "main") ){
+    if( !isAdmin ) return SQLITE_AUTH;
+    pStmt = sqlite3UserAuthPrepare(db, 
+              "CREATE TABLE sqlite_user(\n"
+              "  uname TEXT PRIMARY KEY,\n"
+              "  isAdmin BOOLEAN,\n"
+              "  pw BLOB\n"
+              ") WITHOUT ROWID;");
+    if( pStmt==0 ) return SQLITE_NOMEM;
+    sqlite3_step(pStmt);
+    rc = sqlite3_finalize(pStmt);
+    if( rc ) return rc;
+  }
+  pStmt = sqlite3UserAuthPrepare(db, 
+            "INSERT INTO sqlite_user(uname,isAdmin,pw)"
+            " VALUES(%Q,%d,sqlite_crypt(?1,NULL))",
+            zUsername, isAdmin!=0);
+  if( pStmt==0 ) return SQLITE_NOMEM;
+  sqlite3_bind_blob(pStmt, 1, aPW, nPW, SQLITE_STATIC);
+  sqlite3_step(pStmt);
+  rc = sqlite3_finalize(pStmt);
+  if( rc ) return rc;
+  if( db->auth.zAuthUser==0 ){
+    assert( isAdmin!=0 );
+    sqlite3_user_authenticate(db, zUsername, aPW, nPW);
+  }
+  return SQLITE_OK;
+}
+
+/*
+** The sqlite3_user_change() interface can be used to change a users
+** login credentials or admin privilege.  Any user can change their own
+** login credentials.  Only an admin user can change another users login
+** credentials or admin privilege setting.  No user may change their own 
+** admin privilege setting.
+*/
+int sqlite3_user_change(
+  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
+** database.
+*/
+int sqlite3_user_delete(
+  sqlite3 *db,           /* Database connection */
+  const char *zUsername  /* Username to remove */
+){
+  sqlite3_stmt *pStmt;
+  if( db->auth.authLevel<UAUTH_Admin ){
+    /* Must be an administrator to delete a user */
+    return SQLITE_AUTH;
+  }
+  if( strcmp(db->auth.zAuthUser, zUsername)==0 ){
+    /* Cannot delete self */
+    return SQLITE_AUTH;
+  }
+  if( !userTableExists(db, "main") ){
+    /* This routine is a no-op if the user to be deleted does not exist */
+    return SQLITE_OK;
+  }
+  pStmt = sqlite3UserAuthPrepare(db,
+              "DELETE FROM sqlite_user WHERE uname=%Q", zUsername);
+  if( pStmt==0 ) return SQLITE_NOMEM;
+  sqlite3_step(pStmt);
+  return sqlite3_finalize(pStmt);
+}
+
+#endif /* SQLITE_USER_AUTHENTICATION */