unicode/utf8: reject out-of-range runes.
Surrogates are still admitted, but I have sent mail to golang-dev on that topic.
Fixes #3785.
R=golang-dev, rogpeppe, iant
CC=golang-dev
https://golang.org/cl/6398049
diff --git a/src/pkg/unicode/utf8/utf8.go b/src/pkg/unicode/utf8/utf8.go
index 57ea19e..cd9c80c 100644
--- a/src/pkg/unicode/utf8/utf8.go
+++ b/src/pkg/unicode/utf8/utf8.go
@@ -102,7 +102,7 @@
// 4-byte, 21-bit sequence?
if c0 < t5 {
r = rune(c0&mask4)<<18 | rune(c1&maskx)<<12 | rune(c2&maskx)<<6 | rune(c3&maskx)
- if r <= rune3Max {
+ if r <= rune3Max || MaxRune < r {
return RuneError, 1, false
}
return r, 4, false
@@ -177,7 +177,7 @@
// 4-byte, 21-bit sequence?
if c0 < t5 {
r = rune(c0&mask4)<<18 | rune(c1&maskx)<<12 | rune(c2&maskx)<<6 | rune(c3&maskx)
- if r <= rune3Max {
+ if r <= rune3Max || MaxRune < r {
return RuneError, 1, false
}
return r, 4, false
@@ -202,6 +202,9 @@
// DecodeRune unpacks the first UTF-8 encoding in p and returns the rune and its width in bytes.
// If the encoding is invalid, it returns (RuneError, 1), an impossible result for correct UTF-8.
+// An encoding is invalid if it is incorrect UTF-8, encodes a rune that is
+// out of range, or is not the shortest possible UTF-8 encoding for the
+// value. No other validation is performed.
func DecodeRune(p []byte) (r rune, size int) {
r, size, _ = decodeRuneInternal(p)
return
@@ -209,6 +212,9 @@
// DecodeRuneInString is like DecodeRune but its input is a string.
// If the encoding is invalid, it returns (RuneError, 1), an impossible result for correct UTF-8.
+// An encoding is invalid if it is incorrect UTF-8, encodes a rune that is
+// out of range, or is not the shortest possible UTF-8 encoding for the
+// value. No other validation is performed.
func DecodeRuneInString(s string) (r rune, size int) {
r, size, _ = decodeRuneInStringInternal(s)
return
@@ -216,6 +222,9 @@
// DecodeLastRune unpacks the last UTF-8 encoding in p and returns the rune and its width in bytes.
// If the encoding is invalid, it returns (RuneError, 1), an impossible result for correct UTF-8.
+// An encoding is invalid if it is incorrect UTF-8, encodes a rune that is
+// out of range, or is not the shortest possible UTF-8 encoding for the
+// value. No other validation is performed.
func DecodeLastRune(p []byte) (r rune, size int) {
end := len(p)
if end == 0 {
@@ -250,6 +259,9 @@
// DecodeLastRuneInString is like DecodeLastRune but its input is a string.
// If the encoding is invalid, it returns (RuneError, 1), an impossible result for correct UTF-8.
+// An encoding is invalid if it is incorrect UTF-8, encodes a rune that is
+// out of range, or is not the shortest possible UTF-8 encoding for the
+// value. No other validation is performed.
func DecodeLastRuneInString(s string) (r rune, size int) {
end := len(s)
if end == 0 {
