Disable hz-gb-2312 encoding support

xtext_bug.go

@@ -0,0 +1,37 @@
+//+build !hz_gb_2312
+
+package maddy
+
+import (
+	"errors"
+
+	"github.com/emersion/go-message/charset"
+	"golang.org/x/text/encoding"
+)
+
+/*
+
+Disallow hz-gb-2312 encoding as it can trigger OOM crash.
+
+https://github.com/emersion/go-message/issues/95
+https://github.com/golang/go/issues/35118
+*/
+
+type dummyEncoding struct{}
+
+func (dummyEncoding) NewDecoder() *encoding.Decoder {
+	return &encoding.Decoder{Transformer: dummyEncoding{}}
+}
+func (dummyEncoding) NewEncoder() *encoding.Encoder {
+	return &encoding.Encoder{Transformer: dummyEncoding{}}
+}
+
+func (dummyEncoding) Reset() {}
+
+func (dummyEncoding) Transform(dst, src []byte, atEOF bool) (nDst, nSrc int, err error) {
+	return 0, 0, errors.New("hz-gb-2312 decoding is disabled due to known issues")
+}
+
+func init() {
+	charset.RegisterEncoding("hz-gb-2312", dummyEncoding{})
+}