[release-branch.go1.15] syscall: do not overflow key memory in GetQueuedCompletionStatus

The third argument to GetQueuedCompletionStatus is a pointer to a
uintptr, not a uint32. Users of this functions have therefore been
corrupting their memory every time they used it. Either that memory
corruption was silent (dangerous), or their programs didn't work so they
chose a different API to use.

This fixes the problem by passing through an intermediate buffer.

Updates #44538.
Fixes #44592.

Change-Id: Icacd71f705b36e41e52bd8c4d74898559a27522f
Reviewed-on: https://go-review.googlesource.com/c/go/+/296151
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

2 files changed, 34 insertions, 6 deletions

diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index f62c00d72fe..fbb11a89ca6 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -213,9 +213,9 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetEndOfFile(handle Handle) (err error)
 //sys	GetSystemTimeAsFileTime(time *Filetime)
 //sys	GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, err error) [failretval==0xffffffff]
-//sys	CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, threadcnt uint32) (handle Handle, err error)
-//sys	GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) (err error)
-//sys	PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (err error)
+//sys	createIoCompletionPort(filehandle Handle, cphandle Handle, key uintptr, threadcnt uint32) (handle Handle, err error) = CreateIoCompletionPort
+//sys	getQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uintptr, overlapped **Overlapped, timeout uint32) (err error) = GetQueuedCompletionStatus
+//sys	postQueuedCompletionStatus(cphandle Handle, qty uint32, key uintptr, overlapped *Overlapped) (err error) = PostQueuedCompletionStatus
 //sys	CancelIo(s Handle) (err error)
 //sys	CancelIoEx(s Handle, o *Overlapped) (err error)
 //sys	CreateProcess(appName *uint16, commandLine *uint16, procSecurity *SecurityAttributes, threadSecurity *SecurityAttributes, inheritHandles bool, creationFlags uint32, env *uint16, currentDir *uint16, startupInfo *StartupInfo, outProcInfo *ProcessInformation) (err error) = CreateProcessW
@@ -1209,3 +1209,31 @@ func Readlink(path string, buf []byte) (n int, err error) {
 
 	return n, nil
 }
+
+// Deprecated: CreateIoCompletionPort has the wrong function signature. Use x/sys/windows.CreateIoCompletionPort.
+func CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, threadcnt uint32) (Handle, error) {
+	return createIoCompletionPort(filehandle, cphandle, uintptr(key), threadcnt)
+}
+
+// Deprecated: GetQueuedCompletionStatus has the wrong function signature. Use x/sys/windows.GetQueuedCompletionStatus.
+func GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) error {
+	var ukey uintptr
+	var pukey *uintptr
+	if key != nil {
+		ukey = uintptr(*key)
+		pukey = &ukey
+	}
+	err := getQueuedCompletionStatus(cphandle, qty, pukey, overlapped, timeout)
+	if key != nil {
+		*key = uint32(ukey)
+		if uintptr(*key) != ukey && err == nil {
+			err = errorspkg.New("GetQueuedCompletionStatus returned key overflow")
+		}
+	}
+	return err
+}
+
+// Deprecated: PostQueuedCompletionStatus has the wrong function signature. Use x/sys/windows.PostQueuedCompletionStatus.
+func PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) error {
+	return postQueuedCompletionStatus(cphandle, qty, uintptr(key), overlapped)
+}
diff --git a/src/syscall/zsyscall_windows.go b/src/syscall/zsyscall_windows.go
index 2348f6534f7..2762fb3b74f 100644
--- a/src/syscall/zsyscall_windows.go
+++ b/src/syscall/zsyscall_windows.go
@@ -539,7 +539,7 @@ func GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, err error) {
 	return
 }
 
-func CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, threadcnt uint32) (handle Handle, err error) {
+func createIoCompletionPort(filehandle Handle, cphandle Handle, key uintptr, threadcnt uint32) (handle Handle, err error) {
 	r0, _, e1 := Syscall6(procCreateIoCompletionPort.Addr(), 4, uintptr(filehandle), uintptr(cphandle), uintptr(key), uintptr(threadcnt), 0, 0)
 	handle = Handle(r0)
 	if handle == 0 {
@@ -552,7 +552,7 @@ func CreateIoCompletionPort(filehandle Handle, cphandle Handle, key uint32, thre
 	return
 }
 
-func GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) (err error) {
+func getQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uintptr, overlapped **Overlapped, timeout uint32) (err error) {
 	r1, _, e1 := Syscall6(procGetQueuedCompletionStatus.Addr(), 5, uintptr(cphandle), uintptr(unsafe.Pointer(qty)), uintptr(unsafe.Pointer(key)), uintptr(unsafe.Pointer(overlapped)), uintptr(timeout), 0)
 	if r1 == 0 {
 		if e1 != 0 {
@@ -564,7 +564,7 @@ func GetQueuedCompletionStatus(cphandle Handle, qty *uint32, key *uint32, overla
 	return
 }
 
-func PostQueuedCompletionStatus(cphandle Handle, qty uint32, key uint32, overlapped *Overlapped) (err error) {
+func postQueuedCompletionStatus(cphandle Handle, qty uint32, key uintptr, overlapped *Overlapped) (err error) {
 	r1, _, e1 := Syscall6(procPostQueuedCompletionStatus.Addr(), 4, uintptr(cphandle), uintptr(qty), uintptr(key), uintptr(unsafe.Pointer(overlapped)), 0, 0)
 	if r1 == 0 {
 		if e1 != 0 {