src: normalize malloc, realloc

malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
that the standard allows them to either return a unique pointer or a
nullptr for zero-sized allocation requests.  Normalize by always using
a nullptr.

- Introduce node::malloc, node::realloc and node::calloc that should
  be used throught our source.
- Update all existing node source files to use the new functions
  instead of the native allocation functions.

Fixes: https://github.com/nodejs/node/issues/7549
PR-URL: https://github.com/nodejs/node/pull/7564
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/cares_wrap.cc

@@ -175,7 +175,8 @@ static void ares_poll_close_cb(uv_handle_t* watcher) {
 
 /* Allocates and returns a new node_ares_task */
 static node_ares_task* ares_task_create(Environment* env, ares_socket_t sock) {
-  node_ares_task* task = static_cast<node_ares_task*>(malloc(sizeof(*task)));
+  node_ares_task* task =
+    static_cast<node_ares_task*>(node::Malloc(sizeof(*task)));
 
   if (task == nullptr) {
     /* Out of memory. */

src/node.cc

@@ -978,9 +978,9 @@ void* ArrayBufferAllocator::Allocate(size_t size) {
   if (env_ == nullptr ||
       !env_->array_buffer_allocator_info()->no_zero_fill() ||
       zero_fill_all_buffers)
-    return calloc(size, 1);
+    return node::Calloc(size, 1);
   env_->array_buffer_allocator_info()->reset_fill_flag();
-  return malloc(size);
+  return node::Malloc(size);
 }
 
 static bool DomainHasErrorHandler(const Environment* env,

src/node_buffer.cc

@@ -49,7 +49,7 @@
   size_t length = end - start;
 
 #define BUFFER_MALLOC(length)                                               \
-  zero_fill_all_buffers ? calloc(length, 1) : malloc(length)
+  zero_fill_all_buffers ? node::Calloc(length, 1) : node::Malloc(length)
 
 namespace node {
 
@@ -247,10 +247,6 @@ MaybeLocal<Object> New(Isolate* isolate,
   size_t actual = 0;
   char* data = nullptr;
 
-  // malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
-  // that the standard allows them to either return a unique pointer or a
-  // nullptr for zero-sized allocation requests.  Normalize by always using
-  // a nullptr.
   if (length > 0) {
     data = static_cast<char*>(BUFFER_MALLOC(length));
 
@@ -264,7 +260,7 @@ MaybeLocal<Object> New(Isolate* isolate,
       free(data);
       data = nullptr;
     } else if (actual < length) {
-      data = static_cast<char*>(realloc(data, actual));
+      data = static_cast<char*>(node::Realloc(data, actual));
       CHECK_NE(data, nullptr);
     }
   }
@@ -343,7 +339,7 @@ MaybeLocal<Object> Copy(Environment* env, const char* data, size_t length) {
   void* new_data;
   if (length > 0) {
     CHECK_NE(data, nullptr);
-    new_data = malloc(length);
+    new_data = node::Malloc(length);
     if (new_data == nullptr)
       return Local<Object>();
     memcpy(new_data, data, length);
@@ -931,7 +927,7 @@ void IndexOfString(const FunctionCallbackInfo<Value>& args) {
                           needle_length,
                           offset);
   } else if (enc == BINARY) {
-    uint8_t* needle_data = static_cast<uint8_t*>(malloc(needle_length));
+    uint8_t* needle_data = static_cast<uint8_t*>(node::Malloc(needle_length));
     if (needle_data == nullptr) {
       return args.GetReturnValue().Set(-1);
     }

src/node_crypto.cc

@@ -2090,7 +2090,7 @@ int SSLWrap<Base>::TLSExtStatusCallback(SSL* s, void* arg) {
     size_t len = Buffer::Length(obj);
 
     // OpenSSL takes control of the pointer after accepting it
-    char* data = reinterpret_cast<char*>(malloc(len));
+    char* data = reinterpret_cast<char*>(node::Malloc(len));
     CHECK_NE(data, nullptr);
     memcpy(data, resp, len);
 
@@ -3139,7 +3139,7 @@ bool CipherBase::GetAuthTag(char** out, unsigned int* out_len) const {
   if (initialised_ || kind_ != kCipher || !auth_tag_)
     return false;
   *out_len = auth_tag_len_;
-  *out = static_cast<char*>(malloc(auth_tag_len_));
+  *out = static_cast<char*>(node::Malloc(auth_tag_len_));
   CHECK_NE(*out, nullptr);
   memcpy(*out, auth_tag_, auth_tag_len_);
   return true;
@@ -4694,7 +4694,7 @@ void ECDH::ComputeSecret(const FunctionCallbackInfo<Value>& args) {
   // NOTE: field_size is in bits
   int field_size = EC_GROUP_get_degree(ecdh->group_);
   size_t out_len = (field_size + 7) / 8;
-  char* out = static_cast<char*>(malloc(out_len));
+  char* out = static_cast<char*>(node::Malloc(out_len));
   CHECK_NE(out, nullptr);
 
   int r = ECDH_compute_key(out, out_len, pub, ecdh->key_, nullptr);
@@ -4733,7 +4733,7 @@ void ECDH::GetPublicKey(const FunctionCallbackInfo<Value>& args) {
   if (size == 0)
     return env->ThrowError("Failed to get public key length");
 
-  unsigned char* out = static_cast<unsigned char*>(malloc(size));
+  unsigned char* out = static_cast<unsigned char*>(node::Malloc(size));
   CHECK_NE(out, nullptr);
 
   int r = EC_POINT_point2oct(ecdh->group_, pub, form, out, size, nullptr);
@@ -4762,7 +4762,7 @@ void ECDH::GetPrivateKey(const FunctionCallbackInfo<Value>& args) {
     return env->ThrowError("Failed to get ECDH private key");
 
   int size = BN_num_bytes(b);
-  unsigned char* out = static_cast<unsigned char*>(malloc(size));
+  unsigned char* out = static_cast<unsigned char*>(node::Malloc(size));
   CHECK_NE(out, nullptr);
 
   if (size != BN_bn2bin(b, out)) {
@@ -4839,7 +4839,7 @@ class PBKDF2Request : public AsyncWrap {
         saltlen_(saltlen),
         salt_(salt),
         keylen_(keylen),
-        key_(static_cast<char*>(malloc(keylen))),
+        key_(static_cast<char*>(node::Malloc(keylen))),
         iter_(iter) {
     if (key() == nullptr)
       FatalError("node::PBKDF2Request()", "Out of Memory");
@@ -5002,7 +5002,7 @@ void PBKDF2(const FunctionCallbackInfo<Value>& args) {
 
   THROW_AND_RETURN_IF_NOT_BUFFER(args[1]);
 
-  pass = static_cast<char*>(malloc(passlen));
+  pass = static_cast<char*>(node::Malloc(passlen));
   if (pass == nullptr) {
     FatalError("node::PBKDF2()", "Out of Memory");
   }
@@ -5014,7 +5014,7 @@ void PBKDF2(const FunctionCallbackInfo<Value>& args) {
     goto err;
   }
 
-  salt = static_cast<char*>(malloc(saltlen));
+  salt = static_cast<char*>(node::Malloc(saltlen));
   if (salt == nullptr) {
     FatalError("node::PBKDF2()", "Out of Memory");
   }
@@ -5107,7 +5107,7 @@ class RandomBytesRequest : public AsyncWrap {
       : AsyncWrap(env, object, AsyncWrap::PROVIDER_CRYPTO),
         error_(0),
         size_(size),
-        data_(static_cast<char*>(malloc(size))) {
+        data_(static_cast<char*>(node::Malloc(size))) {
     if (data() == nullptr)
       FatalError("node::RandomBytesRequest()", "Out of Memory");
     Wrap(object, this);
@@ -5336,7 +5336,7 @@ void GetCurves(const FunctionCallbackInfo<Value>& args) {
 
   if (num_curves) {
     alloc_size = sizeof(*curves) * num_curves;
-    curves = static_cast<EC_builtin_curve*>(malloc(alloc_size));
+    curves = static_cast<EC_builtin_curve*>(node::Malloc(alloc_size));
 
     CHECK_NE(curves, nullptr);
 

src/node_internals.h

@@ -216,7 +216,8 @@ class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
   inline void set_env(Environment* env) { env_ = env; }
 
   virtual void* Allocate(size_t size);  // Defined in src/node.cc
-  virtual void* AllocateUninitialized(size_t size) { return malloc(size); }
+  virtual void* AllocateUninitialized(size_t size)
+    { return node::Malloc(size); }
   virtual void Free(void* data, size_t) { free(data); }
 
  private:

src/stream_wrap.cc

@@ -154,7 +154,7 @@ void StreamWrap::OnAlloc(uv_handle_t* handle,
 
 
 void StreamWrap::OnAllocImpl(size_t size, uv_buf_t* buf, void* ctx) {
-  buf->base = static_cast<char*>(malloc(size));
+  buf->base = static_cast<char*>(node::Malloc(size));
   buf->len = size;
 
   if (buf->base == nullptr && size > 0) {
@@ -210,7 +210,7 @@ void StreamWrap::OnReadImpl(ssize_t nread,
     return;
   }
 
-  char* base = static_cast<char*>(realloc(buf->base, nread));
+  char* base = static_cast<char*>(node::Realloc(buf->base, nread));
   CHECK_LE(static_cast<size_t>(nread), buf->len);
 
   if (pending == UV_TCP) {

src/string_bytes.cc

@@ -54,7 +54,7 @@ class ExternString: public ResourceType {
       return scope.Escape(String::Empty(isolate));
 
     TypeName* new_data =
-        static_cast<TypeName*>(malloc(length * sizeof(*new_data)));
+        static_cast<TypeName*>(node::Malloc(length * sizeof(*new_data)));
     if (new_data == nullptr) {
       return Local<String>();
     }
@@ -784,7 +784,7 @@ Local<Value> StringBytes::Encode(Isolate* isolate,
 
     case ASCII:
       if (contains_non_ascii(buf, buflen)) {
-        char* out = static_cast<char*>(malloc(buflen));
+        char* out = static_cast<char*>(node::Malloc(buflen));
         if (out == nullptr) {
           return Local<String>();
         }
@@ -819,7 +819,7 @@ Local<Value> StringBytes::Encode(Isolate* isolate,
 
     case BASE64: {
       size_t dlen = base64_encoded_size(buflen);
-      char* dst = static_cast<char*>(malloc(dlen));
+      char* dst = static_cast<char*>(node::Malloc(dlen));
       if (dst == nullptr) {
         return Local<String>();
       }
@@ -838,7 +838,7 @@ Local<Value> StringBytes::Encode(Isolate* isolate,
 
     case HEX: {
       size_t dlen = buflen * 2;
-      char* dst = static_cast<char*>(malloc(dlen));
+      char* dst = static_cast<char*>(node::Malloc(dlen));
       if (dst == nullptr) {
         return Local<String>();
       }

src/tls_wrap.cc

@@ -662,7 +662,7 @@ void TLSWrap::OnReadImpl(ssize_t nread,
 
 
 void TLSWrap::OnAllocSelf(size_t suggested_size, uv_buf_t* buf, void* ctx) {
-  buf->base = static_cast<char*>(malloc(suggested_size));
+  buf->base = static_cast<char*>(node::Malloc(suggested_size));
   CHECK_NE(buf->base, nullptr);
   buf->len = suggested_size;
 }

src/udp_wrap.cc

@@ -358,7 +358,7 @@ void UDPWrap::OnSend(uv_udp_send_t* req, int status) {
 void UDPWrap::OnAlloc(uv_handle_t* handle,
                       size_t suggested_size,
                       uv_buf_t* buf) {
-  buf->base = static_cast<char*>(malloc(suggested_size));
+  buf->base = static_cast<char*>(node::Malloc(suggested_size));
   buf->len = suggested_size;
 
   if (buf->base == nullptr && suggested_size > 0) {
@@ -400,7 +400,7 @@ void UDPWrap::OnRecv(uv_udp_t* handle,
     return;
   }
 
-  char* base = static_cast<char*>(realloc(buf->base, nread));
+  char* base = static_cast<char*>(node::Realloc(buf->base, nread));
   argv[2] = Buffer::New(env, base, nread).ToLocalChecked();
   argv[3] = AddressToJS(env, addr);
   wrap->MakeCallback(env->onmessage_string(), arraysize(argv), argv);

src/util-inl.h

@@ -217,6 +217,32 @@ bool StringEqualNoCase(const char* a, const char* b) {
   return false;
 }
 
+// These should be used in our code as opposed to the native
+// versions as they abstract out some platform and or
+// compiler version specific functionality.
+// malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
+// that the standard allows them to either return a unique pointer or a
+// nullptr for zero-sized allocation requests.  Normalize by always using
+// a nullptr.
+void* Realloc(void* pointer, size_t size) {
+  if (size == 0) {
+    free(pointer);
+    return nullptr;
+  }
+  return realloc(pointer, size);
+}
+
+// As per spec realloc behaves like malloc if passed nullptr.
+void* Malloc(size_t size) {
+  return Realloc(nullptr, size);
+}
+
+void* Calloc(size_t n, size_t size) {
+  if ((n == 0) || (size == 0)) return nullptr;
+  CHECK_GE(n * size, n);  // Overflow guard.
+  return calloc(n, size);
+}
+
 }  // namespace node
 
 #endif  // SRC_UTIL_INL_H_

src/util.h

@@ -16,6 +16,17 @@
 
 namespace node {
 
+// These should be used in our code as opposed to the native
+// versions as they abstract out some platform and or
+// compiler version specific functionality
+// malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
+// that the standard allows them to either return a unique pointer or a
+// nullptr for zero-sized allocation requests.  Normalize by always using
+// a nullptr.
+inline void* Realloc(void* pointer, size_t size);
+inline void* Malloc(size_t size);
+inline void* Calloc(size_t n, size_t size);
+
 #ifdef __APPLE__
 template <typename T> using remove_reference = std::tr1::remove_reference<T>;
 #else
@@ -250,7 +261,7 @@ class MaybeStackBuffer {
       // Guard against overflow.
       CHECK_LE(storage, sizeof(T) * storage);
 
-      buf_ = static_cast<T*>(malloc(sizeof(T) * storage));
+      buf_ = static_cast<T*>(Malloc(sizeof(T) * storage));
       CHECK_NE(buf_, nullptr);
     }