[PATCH v4 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.

--
  v4: bcryptprimitives: Ensure ProcessPrng fills the whole buffer
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/10187

[PATCH v4 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.
---
 configure                                     |  3 +-
 dlls/bcryptprimitives/main.c                  | 17 +++++++++-
 dlls/bcryptprimitives/tests/Makefile.in       |  4 +++
 .../bcryptprimitives/tests/bcryptprimitives.c | 34 +++++++++++++++++++
 4 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 dlls/bcryptprimitives/tests/Makefile.in
 create mode 100644 dlls/bcryptprimitives/tests/bcryptprimitives.c

diff --git a/configure b/configure
index f632f8e8b0a..e8fb9f92ae8 100755
--- a/configure
+++ b/configure
@@ -22401,6 +22401,7 @@ wine_fn_config_makefile dlls/bcp47langs/tests enable_tests
 wine_fn_config_makefile dlls/bcrypt enable_bcrypt
 wine_fn_config_makefile dlls/bcrypt/tests enable_tests
 wine_fn_config_makefile dlls/bcryptprimitives enable_bcryptprimitives
+wine_fn_config_makefile dlls/bcryptprimitives/tests enable_tests
 wine_fn_config_makefile dlls/bluetoothapis enable_bluetoothapis
 wine_fn_config_makefile dlls/bluetoothapis/tests enable_tests
 wine_fn_config_makefile dlls/browseui enable_browseui
@@ -25051,5 +25052,3 @@ IFS="$ac_save_IFS"
 printf "%s\n" "
 $as_me: Finished.  Do '${MAKE-make}' to compile Wine.
 " >&6
-
-
diff --git a/dlls/bcryptprimitives/main.c b/dlls/bcryptprimitives/main.c
index 6562d672389..689f213d112 100644
--- a/dlls/bcryptprimitives/main.c
+++ b/dlls/bcryptprimitives/main.c
@@ -17,11 +17,26 @@
  */
 
 #include <stdarg.h>
+#include <limits.h>
+
 #include "windef.h"
 #include "winbase.h"
 #include "ntsecapi.h"
 
 BOOL WINAPI ProcessPrng(BYTE *data, SIZE_T size)
 {
-    return RtlGenRandom(data, size);
+    while (size)
+    {
+        SIZE_T len = min( size, (SIZE_T)ULONG_MAX );
+
+        if (!RtlGenRandom( data, len ))
+        {
+            /* This should be unreachable */
+            return FALSE;
+        }
+
+        data += len;
+        size -= len;
+    }
+    return TRUE;
 }
diff --git a/dlls/bcryptprimitives/tests/Makefile.in b/dlls/bcryptprimitives/tests/Makefile.in
new file mode 100644
index 00000000000..50440ab7988
--- /dev/null
+++ b/dlls/bcryptprimitives/tests/Makefile.in
@@ -0,0 +1,4 @@
+TESTDLL  = bcryptprimitives.dll
+
+SOURCES = \
+	bcryptprimitives.c
diff --git a/dlls/bcryptprimitives/tests/bcryptprimitives.c b/dlls/bcryptprimitives/tests/bcryptprimitives.c
new file mode 100644
index 00000000000..d3c8f774d7f
--- /dev/null
+++ b/dlls/bcryptprimitives/tests/bcryptprimitives.c
@@ -0,0 +1,34 @@
+#include <stdlib.h>
+#include <limits.h>
+#include "wine/test.h"
+
+static BOOL (WINAPI *pProcessPrng)(BYTE *data, SIZE_T size);
+
+static void test_ProcessPrng(void)
+{
+    SIZE_T size = (SIZE_T)ULONG_MAX * 2;
+    /* This is a very large allocation that may well fail. */
+    BYTE* buf = malloc(size);
+    if (buf) {
+        BOOL ret = pProcessPrng(buf, size);
+        ok(ret == TRUE, "Expected ProcessPrng to return TRUE, got %d\n", ret);
+        free(buf);
+    }
+}
+
+START_TEST(bcryptprimitives)
+{
+    HMODULE module;
+
+    module = LoadLibraryA("bcryptprimitives.dll");
+    if (!module)
+    {
+        win_skip("bcryptprimitives.dll not found\n");
+        return;
+    }
+    pProcessPrng = (void *)GetProcAddress(module, "ProcessPrng");
+
+    test_ProcessPrng();
+
+    FreeLibrary(module);
+}
-- 
GitLab

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