crypto: implement basic secure heap support

Adds two new command line arguments:

* `--secure-heap=n`, which causes node.js to initialize
  an openssl secure heap of `n` bytes on openssl initialization.
* `--secure-heap-min=n`, which specifies the minimum allocation
  from the secure heap.
* A new method `crypto.secureHeapUsed()` that returns details
  about the total and used secure heap allocation.

The secure heap is an openssl feature that allows certain kinds
of potentially sensitive information (such as private key
BigNums) to be allocated from a dedicated memory area that is
protected against pointer over- and underruns.

The secure heap is a fixed size, so it's important that users
pick a large enough size to cover the crypto operations they
intend to utilize.

The secure heap is disabled by default.

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: https://github.com/nodejs/node/pull/36779
Refs: https://github.com/nodejs/node/pull/36729
Reviewed-By: Tobias Nießen <tniessen@tnie.de>

1 files changed, 24 insertions, 0 deletions

diff --git a/src/node_options.cc b/src/node_options.cc
index e90dcd93231..9f59e7ee4f8 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -7,6 +7,8 @@
 
 #include <errno.h>
 #include <sstream>
+#include <limits>
+#include <algorithm>
 #include <cstdlib>  // strtoul, errno
 
 using v8::Boolean;
@@ -64,6 +66,20 @@ void PerProcessOptions::CheckOptions(std::vector<std::string>* errors) {
     errors->push_back("either --use-openssl-ca or --use-bundled-ca can be "
                       "used, not both");
   }
+
+  // Any value less than 2 disables use of the secure heap.
+  if (secure_heap >= 2) {
+    if ((secure_heap & (secure_heap - 1)) != 0)
+      errors->push_back("--secure-heap must be a power of 2");
+    secure_heap_min =
+        std::min({
+            secure_heap,
+            secure_heap_min,
+            static_cast<int64_t>(std::numeric_limits<int>::max())});
+    secure_heap_min = std::max(static_cast<int64_t>(2), secure_heap_min);
+    if ((secure_heap_min & (secure_heap_min - 1)) != 0)
+      errors->push_back("--secure-heap-min must be a power of 2");
+  }
 #endif
   if (use_largepages != "off" &&
       use_largepages != "on" &&
@@ -760,6 +776,14 @@ PerProcessOptionsParser::PerProcessOptionsParser(
             &PerProcessOptions::force_fips_crypto,
             kAllowedInEnvironment);
 #endif
+  AddOption("--secure-heap",
+            "total size of the OpenSSL secure heap",
+            &PerProcessOptions::secure_heap,
+            kAllowedInEnvironment);
+  AddOption("--secure-heap-min",
+            "minimum allocation size from the OpenSSL secure heap",
+            &PerProcessOptions::secure_heap_min,
+            kAllowedInEnvironment);
 #endif
   AddOption("--use-largepages",
             "Map the Node.js static code to large pages. Options are "