(Fix): fixed unsafe.Slice using &r (pointer-to-pointer) as the backing array instead of r (the calloc'd response array), which wrote password bytes into random stack memory.

src/auth/pam.go

@@ -80,13 +80,22 @@ func latchd_pam_conv(numMsg C.int, msg **C.struct_pam_message, resp **C.struct_p
 	}
 	*resp = r
 
-	s := unsafe.Slice((**C.struct_pam_response)(unsafe.Pointer(&r)), int(numMsg))
+	msgSlice := unsafe.Slice(msg, int(numMsg))
+	respSlice := unsafe.Slice(r, int(numMsg))
+
 	for i := 0; i < int(numMsg); i++ {
-		c := C.CString(pw)
-		if c == nil {
-			return C.PAM_BUF_ERR
+		switch msgSlice[i].msg_style {
+		case C.PAM_PROMPT_ECHO_OFF, C.PAM_PROMPT_ECHO_ON:
+			c := C.CString(pw)
+			if c == nil {
+				return C.PAM_BUF_ERR
+			}
+			respSlice[i].resp = c
+			respSlice[i].resp_retcode = 0
+		default:
+			respSlice[i].resp = nil
+			respSlice[i].resp_retcode = 0
 		}
-		s[i] = &C.struct_pam_response{resp: c, resp_retcode: 0}
 	}
 	return C.PAM_SUCCESS
 }