@nxtedition/shared - npm Package Compare versions

Comparing version 5.1.4 to 5.1.5

lib/index.js

@@ -16,3 +16,4 @@ // By placing the read and write indices far apart (multiples of a common
 //   [4]      PTR_HI  upper 32 bits of native ptr
-//   [5..15]  padding
+//   [5..6]   PTR_CHECK  64-bit hash of the pointer (corruption guard)
+//   [7..15]  padding
 //
@@ -120,6 +121,5 @@ // Cache line 1 (bytes 64–127):
   }
-  // ring_alloc returns a SharedArrayBuffer whose BackingStore holds the state
-  // block and a custom V8 deleter. V8 ref-counts the BackingStore across all
-  // isolates that hold the SAB; when the last one drops it, the deleter fires
-  // and releases the native ring_buf_t — no FinalizationRegistry needed.
+  // The initial ring_buf_t reference is intentionally leaked until
+  // node_api_create_external_shared_array_buffer is available upstream.
+  // See https://github.com/nodejs/node/issues/62259
   return native.ring_alloc(dataSize)
@@ -126,0 +126,0 @@ }

package.json

 {
   "name": "@nxtedition/shared",
-  "version": "5.1.4",
+  "version": "5.1.5",
   "type": "module",
@@ -5,0 +5,0 @@ "main": "lib/index.js",

src/ring.cc

@@ -343,3 +343,4 @@ #define NAPI_EXPERIMENTAL
 //   [4]   PTR_HI  upper 32 bits of ring_buf_t*
-//   [5..15]  padding
+//   [5..6] PTR_CHECK  64-bit hash of the pointer (corruption guard)
+//   [7..15]  padding
 //
@@ -359,3 +360,31 @@ // Cache line 1 (bytes 64–127):
 static const size_t PTR_HI_INDEX = 4;
+static const size_t PTR_CHECK_INDEX = 5; // 2 × uint32 = 64-bit hash
 
+// MurmurHash3 64-bit finalizer — strong bit avalanche for pointer hashing.
+static uint64_t fmix64(uint64_t k)
+{
+  k ^= k >> 33;
+  k *= 0xff51afd7ed558ccdULL;
+  k ^= k >> 33;
+  k *= 0xc4ceb9fe1a85ec53ULL;
+  k ^= k >> 33;
+  return k;
+}
+
+// Computes a 64-bit check value from a pointer and writes it to slots [5..6].
+static void ptr_check_write(uint32_t *s, uintptr_t p)
+{
+  uint64_t h = fmix64(static_cast<uint64_t>(p));
+  s[PTR_CHECK_INDEX + 0] = static_cast<uint32_t>(h);
+  s[PTR_CHECK_INDEX + 1] = static_cast<uint32_t>(h >> 32);
+}
+
+// Validates the 64-bit check value in slots [5..6] against the pointer.
+static bool ptr_check_valid(const uint32_t *s, uintptr_t p)
+{
+  uint64_t h = fmix64(static_cast<uint64_t>(p));
+  return s[PTR_CHECK_INDEX + 0] == static_cast<uint32_t>(h) &&
+         s[PTR_CHECK_INDEX + 1] == static_cast<uint32_t>(h >> 32);
+}
+
 // ─── Helper: extract ring_buf_t* from a SharedHandle ─────────────────────────
@@ -384,3 +413,3 @@
     char msg[128];
-    snprintf(msg, sizeof(msg), "%s: invalid handle (too small)", ctx);
+    snprintf(msg, sizeof(msg), "%s: invalid handle (size)", ctx);
     napi_throw_type_error(env, nullptr, msg);
@@ -394,3 +423,3 @@ return nullptr;
     char msg[128];
-    snprintf(msg, sizeof(msg), "%s: invalid handle (bad magic)", ctx);
+    snprintf(msg, sizeof(msg), "%s: invalid handle (magic)", ctx);
     napi_throw_type_error(env, nullptr, msg);
@@ -402,3 +431,13 @@ return nullptr;
   uint64_t hi = s[PTR_HI_INDEX];
-  return reinterpret_cast<ring_buf_t *>(static_cast<uintptr_t>((hi << 32) | lo));
+  uintptr_t p = static_cast<uintptr_t>((hi << 32) | lo);
+
+  if (!ptr_check_valid(s, p))
+  {
+    char msg[128];
+    snprintf(msg, sizeof(msg), "%s: invalid handle (checksum)", ctx);
+    napi_throw_type_error(env, nullptr, msg);
+    return nullptr;
+  }
+
+  return reinterpret_cast<ring_buf_t *>(p);
 }
@@ -416,12 +455,2 @@
 
-// Finalizer attached via napi_wrap to the SharedArrayBuffer returned by
-// ring_alloc. Releases the initial ring_buf_t reference when the SAB is GC'd
-// in the creating context.
-// NOTE: workaround for missing napi_create_external_shared_array_buffer;
-// see https://github.com/nodejs/node/issues/62259
-static void sab_finalizer(node_api_basic_env /*env*/, void *finalize_data, void * /*finalize_hint*/)
-{
-  ring_buf_release(static_cast<ring_buf_t *>(finalize_data));
-}
-
 // ─── NAPI methods ─────────────────────────────────────────────────────────────
@@ -434,5 +463,7 @@
 //
-// TODO (fix): NAPI has no napi_create_external_shared_array_buffer so we use
-// node_api_create_sharedarraybuffer as a workaround. Once upstream adds external
-// SAB support this can be simplified: https://github.com/nodejs/node/issues/62259
+// NAPI has no napi_create_external_shared_array_buffer yet, so we use
+// node_api_create_sharedarraybuffer and intentionally leak the initial
+// ring_buf_t reference to prevent use-after-free when the SAB is shared
+// across worker threads. Once upstream adds external SAB support, the leak
+// can be eliminated: https://github.com/nodejs/node/issues/62259
 static napi_value ring_alloc(napi_env env, napi_callback_info info)
@@ -483,13 +514,2 @@ {
 
-  // Attach a finalizer to the SAB so the initial ring_buf_t reference is
-  // released when the SAB is GC'd in this context. Workers that receive the
-  // SAB get their own JS object wrapping the same backing store but do not
-  // carry this wrap, so their lifetime is handled by ring_get_array_buffer.
-  if (napi_wrap(env, sab, rb, sab_finalizer, nullptr, nullptr) != napi_ok)
-  {
-    ring_buf_free(rb);
-    napi_throw_error(env, nullptr, "ring_alloc: failed to attach finalizer");
-    return nullptr;
-  }
-
   uint32_t *s = static_cast<uint32_t *>(state_data);
@@ -501,2 +521,3 @@ s[MAGIC1_INDEX] = MAGIC1;
   s[PTR_HI_INDEX] = static_cast<uint32_t>(static_cast<uint64_t>(p) >> 32);
+  ptr_check_write(s, p);
 
@@ -503,0 +524,0 @@ return sab;

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