[PATCH 0/1] MR10187: bcryptprimitives: Ensure ProcessPrng fills the whole buffer

[Christopher Denton (＠cdenton)]

[`ProcessPrng`](https://learn.microsoft.com/en-us/windows/win32/seccng/processprng) takes a `SIZE_T` argument for its length whereas [`RtlGenRandom`](https://learn.microsoft.com/en-us/windows/win32/api/ntsecapi/nf-ntsecapi-rtl...) takes a `ULONG`, which may be smaller.

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10187

[PATCH 1/1] bcryptprimitives: Ensure ProcessPrng fills the whole buffer

[Chris Denton]

From: Chris Denton <[e-mail]>

ProcessPrng takes a SIZE_T argument for its length whereas RtlGenRandom takes a ULONG, which may be smaller.
---
 dlls/bcryptprimitives/main.c | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/dlls/bcryptprimitives/main.c b/dlls/bcryptprimitives/main.c
index 6562d672389..267acdaac16 100644
--- a/dlls/bcryptprimitives/main.c
+++ b/dlls/bcryptprimitives/main.c
@@ -16,12 +16,31 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  */
 
+#include <assert.h>
 #include <stdarg.h>
+#include <limits.h>
+
 #include "windef.h"
 #include "winbase.h"
 #include "ntsecapi.h"
+#include "wine/debug.h"
+
+WINE_DEFAULT_DEBUG_CHANNEL(bcrypt);
 
 BOOL WINAPI ProcessPrng(BYTE *data, SIZE_T size)
 {
-    return RtlGenRandom(data, size);
+    while (size)
+    {
+        SIZE_T len = min( size, ULONG_MAX );
+
+        if (!RtlGenRandom( data, len ))
+        {
+            /* This should be unreachable */
+            return FALSE;
+        }
+
+        data += len;
+        size -= len;
+    }
+    return TRUE;
 }
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/10187