/
prepared_statement_sql_observer.go
449 lines (378 loc) · 15.6 KB
/
prepared_statement_sql_observer.go
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package mysql
import (
"bytes"
"context"
"encoding/hex"
"errors"
"fmt"
"strings"
"github.com/sirupsen/logrus"
"github.com/cossacklabs/acra/decryptor/base"
"github.com/cossacklabs/acra/encryptor"
"github.com/cossacklabs/acra/encryptor/config"
"github.com/cossacklabs/acra/hmac"
"github.com/cossacklabs/acra/logging"
"github.com/cossacklabs/acra/sqlparser"
)
// ErrStatementNotPresentInRegistry represent an error that prepared statement already exist in session registry
var ErrStatementNotPresentInRegistry = errors.New("prepared statement not present in registry")
// PreparedStatementsQuery process MySQL SQL PreparedStatement
type PreparedStatementsQuery struct {
proxyHandler *Handler
parser *sqlparser.Parser
encryptor encryptor.DataEncryptor
schemaStore config.TableSchemaStore
coder encryptor.DBDataCoder
querySelectSettings []*encryptor.QueryDataItem
}
// NewMySQLPreparedStatementsQuery create new PreparedStatementsQuery to handle SQL PreparedStatement in the following format
// https://dev.mysql.com/doc/refman/8.0/en/sql-prepared-statements.html
func NewMySQLPreparedStatementsQuery(proxyHandler *Handler, parser *sqlparser.Parser, schemaStore config.TableSchemaStore) *PreparedStatementsQuery {
return &PreparedStatementsQuery{
proxyHandler,
parser,
nil,
schemaStore,
&encryptor.MysqlDBDataCoder{},
nil,
}
}
// SetDataEncryptor set encryptor.DataEncryptor
func (e *PreparedStatementsQuery) SetDataEncryptor(dataEncryptor encryptor.DataEncryptor) {
e.encryptor = dataEncryptor
}
// ID returns name of this QueryObserver.
func (e *PreparedStatementsQuery) ID() string {
return "PreparedStatementsQuery"
}
// OnColumn return new encryption setting context if info exist, otherwise column data and passed context will be returned
func (e *PreparedStatementsQuery) OnColumn(ctx context.Context, data []byte) (context.Context, []byte, error) {
columnInfo, ok := base.ColumnInfoFromContext(ctx)
if ok && e.querySelectSettings != nil {
// return context with encryption setting
if columnInfo.Index() < len(e.querySelectSettings) {
selectSetting := e.querySelectSettings[columnInfo.Index()]
if selectSetting != nil {
logging.GetLoggerFromContext(ctx).WithField("column_index", columnInfo.Index()).WithField("column", selectSetting.ColumnName()).Debugln("Set encryption setting")
return encryptor.NewContextWithEncryptionSetting(ctx, selectSetting.Setting()), data, nil
}
}
}
return ctx, data, nil
}
// OnQuery processes query text before database sees it.
func (e *PreparedStatementsQuery) OnQuery(ctx context.Context, query base.OnQueryObject) (base.OnQueryObject, bool, error) {
logrus.Debugln("PreparedStatementsQuery.OnQuery")
e.querySelectSettings = nil
parsedQuery, err := query.Statement()
if err != nil {
logrus.WithError(err).Debugln("Can't parse SQL statement")
return query, false, nil
}
switch processQuery := parsedQuery.(type) {
case *sqlparser.Prepare:
return e.onPrepare(ctx, processQuery)
case *sqlparser.Set:
return e.onSet(ctx, processQuery)
case *sqlparser.Execute:
return e.onExecute(ctx, processQuery)
case *sqlparser.DeallocatePrepare:
return e.onDeallocate(ctx, processQuery)
default:
return query, false, nil
}
}
func (e *PreparedStatementsQuery) onPrepare(ctx context.Context, prepareQuery *sqlparser.Prepare) (base.OnQueryObject, bool, error) {
logrus.Debugln("PreparedStatementsQuery.Prepare")
var preparedStatementName = prepareQuery.PreparedStatementName.ValueForConfig()
// MySQL allows create statements many time, so just log in case of already registered
_, err := e.proxyHandler.registry.StatementByID(preparedStatementName)
if err == nil {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("PreparedStatement already stored in registry")
}
stmt, ok := prepareQuery.PreparedStatementQuery.(sqlparser.Statement)
if !ok {
if ident, ok := prepareQuery.PreparedStatementQuery.(sqlparser.TableIdent); ok {
logrus.Debugln("Got PreparedStatement with SetArg query")
setArgStmt, err := e.proxyHandler.registry.StatementByID(ident.String())
if err != nil {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("SetArg PreparedStatement not in registry")
return nil, false, err
}
setArgPreparedStatement := setArgStmt.Statement()
// add new PreparedStatement using different name
// 1. SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
// - store in registry with name @s
// 2. On PREPARE stmt2 FROM @s;
// - reset with name stmt2 to use in execute statement
// 3. On EXECUTE stmt2 USING @a, @b;
// - read by stmt2 name
var preparedStatement = NewPreparedStatementWithName(preparedStatementName, setArgPreparedStatement.QueryText(), setArgPreparedStatement.Query())
var preparedStatementItem = NewPreparedStatementItem(preparedStatement, setArgStmt.QuerySettings())
e.proxyHandler.registry.AddStatement(preparedStatementItem)
} else {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
Errorln("Error to cast PreparedStatementQuery to sqlparser.Statement")
}
return nil, false, nil
}
changedObject, changed, err := e.onQuery(ctx, preparedStatementName, base.NewOnQueryObjectFromStatement(stmt, e.parser))
if err != nil {
return nil, false, err
}
if changed {
if err := e.updateChangedQuery(changedObject); err != nil {
return nil, false, err
}
changedStatement, _ := changedObject.Statement()
changedPreparedQuery, ok := changedStatement.(sqlparser.PreparedQuery)
if !ok {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("Failed to cast changedStatement to PreparedQuery")
return nil, false, err
}
prepareQuery.PreparedStatementQuery = changedPreparedQuery
}
logrus.WithField("prepared_name", preparedStatementName).Debug("Registered new prepared statement")
return base.NewOnQueryObjectFromStatement(prepareQuery, e.parser), changed, nil
}
func (e *PreparedStatementsQuery) onSet(ctx context.Context, setQuery *sqlparser.Set) (base.OnQueryObject, bool, error) {
logrus.Debugln("PreparedStatementsQuery.Set Query")
var changedRes bool
for _, arg := range setQuery.Exprs {
sqlVal, ok := arg.Expr.(*sqlparser.SQLVal)
if !ok {
logrus.Debugln("Set Arg is not SQLVal statement")
continue
}
argName := arg.Name.ValueForConfig()
ok, err := e.handleQueryFromSetArg(ctx, sqlVal, argName)
if ok {
logrus.Debugln("New PreparedStatement from Set Arg")
changedRes = true
continue
}
encryptedData, err := e.handleColumnFromSetArg(ctx, sqlVal, argName)
if err != nil {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("Failed to handle column from Set arg")
return nil, false, err
}
if encryptedData != nil && !bytes.Equal(encryptedData, sqlVal.Val) {
output := make([]byte, hex.EncodedLen(len(encryptedData)))
hex.Encode(output, encryptedData)
sqlVal.Val = output
sqlVal.Type = sqlparser.HexVal
changedRes = true
}
}
return base.NewOnQueryObjectFromStatement(setQuery, e.parser), changedRes, nil
}
func (e *PreparedStatementsQuery) handleColumnFromSetArg(ctx context.Context, sqlVal *sqlparser.SQLVal, argName string) ([]byte, error) {
// MySQL set arg query format:
// SET @a = 3;
// Acra expect arguments in the following format: {table_from_encryptor_config}{delimiter}{column_from_encryptor_config}, e.g
// users__name - where `__` is the default delimiter could be overwritten
var delim = e.schemaStore.GetDatabaseSettings().GetMySQLDatabaseSettings().GetPreparedStatementsSetArgDelimiter()
splits := strings.Split(argName, delim)
if len(splits) != 2 {
logrus.WithField("argument", argName).Debugln("unexpected Set arg name for processing")
return nil, nil
}
var columnName = splits[1]
var tableName = strings.TrimPrefix(splits[0], "@")
schema := e.schemaStore.GetTableSchema(tableName)
if schema == nil {
logrus.Debugf("Hasn't schema for table in SET query %s", tableName)
return nil, nil
}
columnSetting := schema.GetColumnEncryptionSettings(columnName)
if columnSetting == nil {
logrus.Debugf("No column encryption setting %s", columnName)
return nil, nil
}
accessContext := base.AccessContextFromContext(ctx)
clientID := columnSetting.ClientID()
if len(clientID) > 0 {
logrus.WithField("client_id", string(clientID)).Debugln("Encrypt with specific ClientID for column")
} else {
logrus.WithField("client_id", string(accessContext.GetClientID())).Debugln("Encrypt with ClientID from connection")
clientID = accessContext.GetClientID()
}
rawData, err := e.coder.Decode(sqlVal, columnSetting)
if err != nil {
return nil, err
}
encryptedData, err := e.encryptor.EncryptWithClientID(clientID, rawData, columnSetting)
if err != nil {
return nil, err
}
return encryptedData, nil
}
func (e *PreparedStatementsQuery) handleQueryFromSetArg(ctx context.Context, sqlVal *sqlparser.SQLVal, argName string) (bool, error) {
// Prepared statement could be supply the text of the statement as a user variable:
// SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse';
// PREPARE stmt2 FROM @s;
// https://dev.mysql.com/doc/refman/8.0/en/sql-prepared-statements.html
//TODO: potentially we can get it from sqlparser directly
prepareQuery, err := sqlparser.NewPreparedQueryFromString(string(sqlVal.Val))
if err != nil || prepareQuery == nil {
return false, nil
}
queryObj := base.NewOnQueryObjectFromStatement(prepareQuery.(sqlparser.Statement), e.parser)
changedObject, changed, err := e.onQuery(ctx, argName, queryObj)
if err != nil {
return false, err
}
if changed {
if err := e.updateChangedQuery(changedObject); err != nil {
return false, err
}
sqlVal.Val = []byte(changedObject.Query())
}
return changed, nil
}
func (e *PreparedStatementsQuery) onExecute(ctx context.Context, executeQuery *sqlparser.Execute) (base.OnQueryObject, bool, error) {
logrus.Debugln("PreparedStatementsQuery.Execute")
var preparedStatementName = executeQuery.PreparedStatementName.ValueForConfig()
stmtItem, err := e.proxyHandler.registry.StatementByID(preparedStatementName)
if err != nil {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("PreparedStatement not present in registry")
return nil, false, ErrStatementNotPresentInRegistry
}
logrus.Debugln("Set query settings from registry")
e.querySelectSettings = stmtItem.QuerySettings()
return base.NewOnQueryObjectFromStatement(executeQuery, e.parser), true, nil
}
func (e *PreparedStatementsQuery) onDeallocate(ctx context.Context, deallocateQuery *sqlparser.DeallocatePrepare) (base.OnQueryObject, bool, error) {
logrus.Debugln("PreparedStatementsQuery.Deallocate")
var preparedStatementName = deallocateQuery.PreparedStatementName.String()
if _, err := e.proxyHandler.registry.StatementByID(deallocateQuery.PreparedStatementName.String()); err != nil {
logrus.WithField(logging.FieldKeyEventCode, logging.EventCodeErrorGeneral).
WithError(err).Errorln("PreparedStatement not present in registry")
return nil, false, ErrStatementNotPresentInRegistry
}
e.querySelectSettings = nil
e.proxyHandler.registry.DeleteStatementByID(preparedStatementName)
return nil, false, nil
}
func (e *PreparedStatementsQuery) onQuery(ctx context.Context, preparedStatementName string, queryObj base.OnQueryObject) (base.OnQueryObject, bool, error) {
stmt, err := queryObj.Statement()
if err != nil {
return nil, false, err
}
var query = queryObj.Query()
var preparedStatement = NewPreparedStatementWithName(preparedStatementName, query, stmt)
changedObject, changed, err := e.proxyHandler.queryObserverManager.OnQuery(ctx, queryObj)
if err != nil {
logrus.WithError(err).WithField(logging.FieldKeyEventCode, logging.EventCodeErrorEncryptQueryData).Errorln("Error occurred in OnQuery handler")
return nil, false, err
}
var querySetting []*encryptor.QueryDataItem
switch query := stmt.(type) {
case *sqlparser.Select:
querySetting, err = encryptor.ParseQuerySettings(ctx, query, e.schemaStore)
if err != nil {
logrus.WithError(err).WithField(logging.FieldKeyEventCode, logging.EventCodeErrorEncryptQueryData).Errorln("Failed to parse querySettings for select in Prepare")
return nil, false, err
}
}
e.proxyHandler.registry.AddStatement(NewPreparedStatementItem(preparedStatement, querySetting))
return changedObject, changed, nil
}
// OnBind just a stub method of QueryObserver of PreparedStatementsQuery
func (e *PreparedStatementsQuery) OnBind(ctx context.Context, statement sqlparser.Statement, values []base.BoundValue) ([]base.BoundValue, bool, error) {
logrus.Debugln("PreparedStatementsQuery.OnBind")
return values, false, nil
}
func (e *PreparedStatementsQuery) updateChangedQuery(changedObject base.OnQueryObject) error {
changedStatement, err := changedObject.Statement()
if err != nil {
return err
}
items := e.filterSearchableComparisons(changedStatement)
if len(items) == 0 {
return nil
}
hashSize := []byte(fmt.Sprintf("%d", hmac.GetDefaultHashSize()))
for _, item := range items {
if !item.Setting.IsSearchable() {
continue
}
if rVal, ok := item.Expr.Right.(*sqlparser.SQLVal); ok && bytes.HasPrefix(rVal.Val, []byte(":v")) {
logrus.Debugln("OnPrepare: replace placeholder with substr for search")
item.Expr.Right = &sqlparser.SubstrExpr{
Name: &sqlparser.ColName{
Name: sqlparser.NewColIdentUnquote("?"),
},
From: sqlparser.NewIntVal([]byte{'1'}),
To: sqlparser.NewIntVal(hashSize),
}
}
}
return nil
}
func (e *PreparedStatementsQuery) filterSearchableComparisons(statement sqlparser.Statement) []encryptor.SearchableExprItem {
tableExps, err := encryptor.FilterTableExpressions(statement)
if err != nil {
logrus.Debugln("Unsupported search query")
return nil
}
// Walk through WHERE clauses of a SELECT statements...
whereExprs, err := encryptor.GetWhereStatements(statement)
if err != nil {
logrus.WithError(err).Debugln("Failed to extract WHERE clauses")
return nil
}
var searchableExprs []encryptor.SearchableExprItem
for _, whereExpr := range whereExprs {
comparisonExprs, err := e.filterColumnEqualComparisonExprs(whereExpr, tableExps)
if err != nil {
logrus.WithError(err).Debugln("Failed to extract comparison expressions")
return nil
}
searchableExprs = append(searchableExprs, comparisonExprs...)
}
return searchableExprs
}
// filterColumnEqualComparisonExprs return only <ColName> = <VALUE> or <ColName> != <VALUE> or <ColName> <=> <VALUE> expressions
func (e *PreparedStatementsQuery) filterColumnEqualComparisonExprs(stmt sqlparser.SQLNode, tableExpr sqlparser.TableExprs) ([]encryptor.SearchableExprItem, error) {
var exprs []encryptor.SearchableExprItem
err := sqlparser.Walk(func(node sqlparser.SQLNode) (kontinue bool, err error) {
comparisonExpr, ok := node.(*sqlparser.ComparisonExpr)
if !ok {
return true, nil
}
lColumn, ok := comparisonExpr.Left.(*sqlparser.SubstrExpr)
if !ok {
return true, nil
}
rColumn, ok := comparisonExpr.Right.(*sqlparser.SQLVal)
if !ok {
return true, nil
}
if !strings.HasPrefix(string(rColumn.Val), ":v") {
return true, nil
}
columnInfo, err := encryptor.FindColumnInfo(tableExpr, lColumn.Name, e.schemaStore)
if err != nil {
return true, nil
}
lColumnSetting := encryptor.GetColumnSetting(lColumn.Name, columnInfo.Table, e.schemaStore)
if lColumnSetting == nil {
return true, nil
}
if !lColumnSetting.IsSearchable() {
return true, nil
}
exprs = append(exprs, encryptor.SearchableExprItem{
Expr: comparisonExpr,
Setting: lColumnSetting,
})
return true, nil
}, stmt)
return exprs, err
}