[RFC PATCH] Prepare random/win32.c fast poll for 64-bit Windows

[Jussi Kivilinna]

* random/win32.c (_gcry_rndw32_gather_random_fast) [ADD]: Rename to
ADDINT.
(_gcry_rndw32_gather_random_fast): Add ADDPTR.
(_gcry_rndw32_gather_random_fast): Disable entropy gathering from
GetQueueStatus(QS_ALLEVENTS).
(_gcry_rndw32_gather_random_fast): Change minimumWorkingSetSize and
maximumWorkingSetSize to SIZE_T from DWORD.
(_gcry_rndw32_gather_random_fast): Only add lower 32-bits of
minimumWorkingSetSize and maximumWorkingSetSize to random poll.
(_gcry_rndw32_gather_random_fast) [__WIN64__]: Read TSC directly
using intrinsic.
--

Introduce entropy gatherer changes related to 64-bit Windows platform as done
in cryptlib fast poll:
 - Change ADD macro to ADDPTR/ADDINT to handle pointer values. ADDPTR
   discards high 32-bits of 64-bit pointer values.
 - minimum/maximumWorkingSetSize changed to SIZE_T type to avoid stack
   corruption on 64-bit; only low 32-bits are used for entropy.
 - Use __rdtsc() intrinsic on 64-bit (as TSC is always available).

Signed-off-by: Jussi Kivilinna <jussi.kivilinna at iki.fi>

--
Would this be enough for 64-bit Windows support?

Slow poll differences cryptlib vs libgcrypt appear to be limited to sensor
data reading from third party programs and reading of PnP data.
---
 random/rndw32.c |   83 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 52 insertions(+), 31 deletions(-)

diff --git a/random/rndw32.c b/random/rndw32.c
index 5c5d6c6..7e78b50 100644
--- a/random/rndw32.c
+++ b/random/rndw32.c
@@ -826,39 +826,47 @@ _gcry_rndw32_gather_random_fast (void (*add)(const void*, size_t,
      cursor position for last message, 1 ms time for last message,
      handle of window with clipboard open, handle of process heap,
      handle of procs window station, types of events in input queue,
-     and milliseconds since Windows was started.  */
+     and milliseconds since Windows was started. On 64-bit platform
+     some of these return values are pointers and thus 64-bit wide.
+     We discard the upper 32-bit of those values.  */
 
   {
     byte buffer[20*sizeof(ulong)], *bufptr;
 
     bufptr = buffer;
-#define ADD(f)  do { ulong along = (ulong)(f);                  \
-                     memcpy (bufptr, &along, sizeof (along) );  \
-                     bufptr += sizeof (along);                  \
-                   } while (0)
-
-    ADD ( GetActiveWindow ());
-    ADD ( GetCapture ());
-    ADD ( GetClipboardOwner ());
-    ADD ( GetClipboardViewer ());
-    ADD ( GetCurrentProcess ());
-    ADD ( GetCurrentProcessId ());
-    ADD ( GetCurrentThread ());
-    ADD ( GetCurrentThreadId ());
-    ADD ( GetDesktopWindow ());
-    ADD ( GetFocus ());
-    ADD ( GetInputState ());
-    ADD ( GetMessagePos ());
-    ADD ( GetMessageTime ());
-    ADD ( GetOpenClipboardWindow ());
-    ADD ( GetProcessHeap ());
-    ADD ( GetProcessWindowStation ());
-    ADD ( GetQueueStatus (QS_ALLEVENTS));
-    ADD ( GetTickCount ());
+#define ADDINT(f)  do { ulong along = (ulong)(f);                  \
+                        memcpy (bufptr, &along, sizeof (along) );  \
+                        bufptr += sizeof (along);                  \
+                      } while (0)
+#define ADDPTR(f)  do { void *aptr = (f);                          \
+                        ADDINT((SIZE_T)aptr);                      \
+                      } while (0)
+
+    ADDPTR ( GetActiveWindow ());
+    ADDPTR ( GetCapture ());
+    ADDPTR ( GetClipboardOwner ());
+    ADDPTR ( GetClipboardViewer ());
+    ADDPTR ( GetCurrentProcess ());
+    ADDINT ( GetCurrentProcessId ());
+    ADDPTR ( GetCurrentThread ());
+    ADDINT ( GetCurrentThreadId ());
+    ADDPTR ( GetDesktopWindow ());
+    ADDPTR ( GetFocus ());
+    ADDINT ( GetInputState ());
+    ADDINT ( GetMessagePos ());
+    ADDINT ( GetMessageTime ());
+    ADDPTR ( GetOpenClipboardWindow ());
+    ADDPTR ( GetProcessHeap ());
+    ADDPTR ( GetProcessWindowStation ());
+    /* Following function in some cases stops returning events, and cannot
+       be used as an entropy source.  */
+    /*ADDINT ( GetQueueStatus (QS_ALLEVENTS));*/
+    ADDINT ( GetTickCount ());
 
     gcry_assert ( bufptr-buffer < sizeof (buffer) );
     (*add) ( buffer, bufptr-buffer, origin );
-#undef ADD
+#undef ADDINT
+#undef ADDPTR
   }
 
   /* Get multiword system information: Current caret position, current
@@ -888,7 +896,7 @@ _gcry_rndw32_gather_random_fast (void (*add)(const void*, size_t,
   {
     HANDLE handle;
     FILETIME creationTime, exitTime, kernelTime, userTime;
-    DWORD minimumWorkingSetSize, maximumWorkingSetSize;
+    SIZE_T minimumWorkingSetSize, maximumWorkingSetSize;
 
     handle = GetCurrentThread ();
     GetThreadTimes (handle, &creationTime, &exitTime,
@@ -910,10 +918,9 @@ _gcry_rndw32_gather_random_fast (void (*add)(const void*, size_t,
        process.  */
     GetProcessWorkingSetSize (handle, &minimumWorkingSetSize,
                               &maximumWorkingSetSize);
-    (*add) ( &minimumWorkingSetSize,
-             sizeof (minimumWorkingSetSize), origin );
-    (*add) ( &maximumWorkingSetSize,
-             sizeof (maximumWorkingSetSize), origin );
+    /* On 64-bit system, discard the high 32-bits. */
+    (*add) ( &minimumWorkingSetSize, sizeof (int), origin );
+    (*add) ( &maximumWorkingSetSize, sizeof (int), origin );
   }
 
 
@@ -961,7 +968,20 @@ _gcry_rndw32_gather_random_fast (void (*add)(const void*, size_t,
 
      To make things unambiguous, we detect a CPU new enough to call RDTSC
      directly by checking for CPUID capabilities, and fall back to QPC if
-     this isn't present.  */
+     this isn't present.
+
+     On AMD64, TSC is always available and intrinsic is provided for accessing
+     it.  */
+#ifdef __WIN64__
+    {
+      unsigned __int64 aint64;
+
+      /* Note: cryptlib does not discard upper 32 bits of TSC on WIN64, but does
+       * on WIN32.  Is this correct?  */
+      aint64 = __rdtsc();
+      (*add) (&aint64, sizeof(aint64), origin);
+    }
+#else
 #ifdef __GNUC__
 /*   FIXME: We would need to implement the CPU feature tests first.  */
 /*   if (cpu_has_feature_rdtsc) */
@@ -990,6 +1010,7 @@ _gcry_rndw32_gather_random_fast (void (*add)(const void*, size_t,
           (*add) (&aword, sizeof (aword), origin );
         }
     }
+#endif /*__WIN64__*/
 
 
 }