Initial import

keyring_windows.go

@@ -0,0 +1,104 @@
+package secret
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var (
+	modadvapi32          = windows.NewLazySystemDLL("advapi32.dll")
+	procCredRead         = modadvapi32.NewProc("CredReadW")
+	procCredFree winproc = modadvapi32.NewProc("CredFree")
+)
+
+// Interface for syscall.Proc: helps testing
+type winproc interface {
+	Call(a ...uintptr) (r1, r2 uintptr, lastErr error)
+}
+
+type keyring struct {
+	service string
+}
+
+func keyringProvider(service string) (Provider, error) {
+	return keyring{service}, nil
+}
+
+func (p keyring) GetSecret(key string) (value []byte, err error) {
+	return sysCredRead(p.service+":"+key, sysCRED_TYPE_GENERIC)
+}
+
+// https://docs.microsoft.com/en-us/windows/desktop/api/wincred/ns-wincred-_credentialw
+type sysCREDENTIAL struct {
+	Flags              uint32
+	Type               uint32
+	TargetName         *uint16
+	Comment            *uint16
+	LastWritten        windows.Filetime
+	CredentialBlobSize uint32
+	CredentialBlob     uintptr
+	Persist            uint32
+	AttributeCount     uint32
+	Attributes         uintptr
+	TargetAlias        *uint16
+	UserName           *uint16
+}
+
+// https://docs.microsoft.com/en-us/windows/desktop/api/wincred/ns-wincred-_credentialw
+type sysCRED_TYPE uint32
+
+const (
+	sysCRED_TYPE_GENERIC                 sysCRED_TYPE = 0x1
+	sysCRED_TYPE_DOMAIN_PASSWORD         sysCRED_TYPE = 0x2
+	sysCRED_TYPE_DOMAIN_CERTIFICATE      sysCRED_TYPE = 0x3
+	sysCRED_TYPE_DOMAIN_VISIBLE_PASSWORD sysCRED_TYPE = 0x4
+	sysCRED_TYPE_GENERIC_CERTIFICATE     sysCRED_TYPE = 0x5
+	sysCRED_TYPE_DOMAIN_EXTENDED         sysCRED_TYPE = 0x6
+)
+
+// https://docs.microsoft.com/en-us/windows/desktop/api/wincred/nf-wincred-credreadw
+func sysCredRead(targetName string, typ sysCRED_TYPE) ([]byte, error) {
+	var pcred *sysCREDENTIAL
+	targetNamePtr, _ := windows.UTF16PtrFromString(targetName)
+	ret, _, err := syscall.SyscallN(
+		procCredRead.Addr(),
+		uintptr(unsafe.Pointer(targetNamePtr)),
+		uintptr(typ),
+		0,
+		uintptr(unsafe.Pointer(&pcred)),
+	)
+	if ret == 0 {
+		return nil, err
+	}
+	defer procCredFree.Call(uintptr(unsafe.Pointer(pcred)))
+
+	return goBytes(pcred.CredentialBlob, pcred.CredentialBlobSize), nil
+}
+
+// goBytes copies the given C byte array to a Go byte array (see `C.GoBytes`).
+// This function avoids having cgo as dependency.
+func goBytes(src uintptr, len uint32) []byte {
+	if src == uintptr(0) {
+		return []byte{}
+	}
+	rv := make([]byte, len)
+	copy(rv, *(*[]byte)(unsafe.Pointer(&struct {
+		Data unsafe.Pointer
+		Len  int
+		Cap  int
+	}{
+		Data: unsafe.Pointer(src),
+		Len:  int(len),
+		Cap:  int(len),
+	})))
+	/*
+		copy(rv, *(*[]byte)(unsafe.Pointer(&reflect.SliceHeader{
+			Data: src,
+			Len:  int(len),
+			Cap:  int(len),
+		})))
+	*/
+	return rv
+}