Add random to Open Enclave Pal

src/pal/pal_open_enclave.h

@@ -7,6 +7,7 @@
 #include <array>
 #ifdef OPEN_ENCLAVE
 extern "C" void* oe_memset_s(void* p, size_t p_size, int c, size_t size);
+extern "C" int oe_random(void* data, size_t size);
 extern "C" [[noreturn]] void oe_abort();
 
 namespace snmalloc
@@ -37,7 +38,7 @@ namespace snmalloc
      * Bitmap of PalFeatures flags indicating the optional features that this
      * PAL supports.
      */
-    static constexpr uint64_t pal_features = 0;
+    static constexpr uint64_t pal_features = Entropy;
 
     static constexpr size_t page_size = Aal::smallest_page_size;
 
@@ -66,6 +67,17 @@ namespace snmalloc
     {
       oe_memset_s(p, size, 0, size);
     }
+
+    /**
+     * Source of Entropy
+     */
+    static uint64_t get_entropy64()
+    {
+      uint64_t result = 0;
+      if (oe_random(&result, sizeof(result)) != 0)
+        error("Failed to get system randomness");
+      return result;
+    }
   };
 }
 #endif

src/test/func/fixed_region/fixed_region.cc

@@ -15,6 +15,14 @@ extern "C" void* oe_memset_s(void* p, size_t p_size, int c, size_t size)
   return memset(p, c, size);
 }
 
+extern "C" int oe_random(void* p, size_t p_size)
+{
+  UNUSED(p_size);
+  UNUSED(p);
+  // Stub for random data.
+  return 0;
+}
+
 extern "C" void oe_abort()
 {
   abort();

src/test/func/two_alloc_types/main.cc

@@ -11,6 +11,14 @@ extern "C" void* oe_memset_s(void* p, size_t p_size, int c, size_t size)
   return memset(p, c, size);
 }
 
+extern "C" int oe_random(void* p, size_t p_size)
+{
+  UNUSED(p_size);
+  UNUSED(p);
+  // Stub for random data.
+  return 0;
+}
+
 extern "C" void oe_abort()
 {
   abort();