SecurityPkg/RngDxe: add rng test

Check whenever RngLib actually returns random numbers, only return a non-zero number of Algorithms if that is the case. This has the effect that RndDxe loads and installs EFI_RNG_PROTOCOL only in case it can actually deliver random numbers. Signed-off-by: Gerd Hoffmann <[email protected]>
Wenxing-hou · Jun 13, 2024 · a61bc0a · a61bc0a
1 parent c3a8ca7
commit a61bc0a
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c b/SecurityPkg/RandomNumberGenerator/RngDxe/Rand/RngDxe.c
@@ -23,6 +23,7 @@
 
 #include <Library/BaseLib.h>
 #include <Library/BaseMemoryLib.h>
+#include <Library/RngLib.h>
 
 #include "RngDxeInternals.h"
 
@@ -43,7 +44,12 @@ GetAvailableAlgorithms (
   VOID
   )
 {
-  mAvailableAlgoArrayCount = RNG_ALGORITHM_COUNT;
+  UINT64  RngTest;
+
+  if (GetRandomNumber64 (&RngTest)) {
+    mAvailableAlgoArrayCount = RNG_ALGORITHM_COUNT;
+  }
+
   return EFI_SUCCESS;
 }