windows: fix slicing of NTUnicodeString values
We were slicing using a count of bytes, not a count of uint16s.
Fixes golang/go#73460
Change-Id: If0fd19e795078c01fda5b976e3c34af115b25dcc
Reviewed-on: https://go-review.googlesource.com/c/sys/+/667235
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Junyang Shao <shaojunyang@google.com>
Reviewed-by: Quim Muntal <quimmuntal@gmail.com>
Auto-Submit: Keith Randall <khr@google.com>
Reviewed-by: Keith Randall <khr@google.com>
diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index 4a32543..044fac4 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -1698,8 +1698,9 @@
// Slice returns a uint16 slice that aliases the data in the NTUnicodeString.
func (s *NTUnicodeString) Slice() []uint16 {
- slice := unsafe.Slice(s.Buffer, s.MaximumLength)
- return slice[:s.Length]
+ // Note: this rounds the length down, if it happens
+ // to (incorrectly) be odd. Probably safer than rounding up.
+ return unsafe.Slice(s.Buffer, s.MaximumLength/2)[:s.Length/2]
}
func (s *NTUnicodeString) String() string {
diff --git a/windows/syscall_windows_test.go b/windows/syscall_windows_test.go
index 1e686a4..f81fea0 100644
--- a/windows/syscall_windows_test.go
+++ b/windows/syscall_windows_test.go
@@ -1473,3 +1473,23 @@
t.Errorf("UnloadKeyboardLayout failed: %v", err)
}
}
+
+func TestRoundtripNTUnicodeString(t *testing.T) {
+ for _, s := range []string{
+ "",
+ "hello",
+ "Ƀ",
+ strings.Repeat("*", 32000), // NTUnicodeString works up to 2^16 byte lengths == 32768 uint16s.
+ // TODO: various encoding errors?
+ } {
+ ntus, err := windows.NewNTUnicodeString(s)
+ if err != nil {
+ t.Errorf("encoding %q failed: %v", s, err)
+ continue
+ }
+ s2 := ntus.String()
+ if s != s2 {
+ t.Errorf("round trip of %q = %q, wanted original", s, s2)
+ }
+ }
+}
diff --git a/windows/types_windows.go b/windows/types_windows.go
index ad67df2..ce741c9 100644
--- a/windows/types_windows.go
+++ b/windows/types_windows.go
@@ -2700,6 +2700,8 @@
// NTUnicodeString is a UTF-16 string for NT native APIs, corresponding to UNICODE_STRING.
type NTUnicodeString struct {
+ // Note: Length and MaximumLength are in *bytes*, not uint16s.
+ // They should always be even.
Length uint16
MaximumLength uint16
Buffer *uint16
