zlib: fix node crashing on invalid options

This is a partial backport of semver-patch bits of
9e4660b5187d4be6a1484e705dc735c0e76ffafa.

This commit fixes the Node process crashing when constructors of classes
of the zlib module are given invalid options.

* Throw an Error when the zlib library rejects the value of windowBits,
  instead of crashing with an assertion.

* Treat windowBits and memLevel options consistently with other ones and
  don't crash when non-numeric values are given.

Backport-PR-URL: https://github.com/nodejs/node/pull/14860
PR-URL: https://github.com/nodejs/node/pull/13098
Fixes: https://github.com/nodejs/node/issues/13082
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>

2 files changed, 20 insertions, 7 deletions

diff --git a/lib/zlib.js b/lib/zlib.js
index 079c413e2f..6d77f0240e 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -373,9 +373,19 @@ function Zlib(opts, mode) {
   var strategy = exports.Z_DEFAULT_STRATEGY;
   if (typeof opts.strategy === 'number') strategy = opts.strategy;
 
-  this._handle.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
+  var windowBits = exports.Z_DEFAULT_WINDOWBITS;
+  if (opts.windowBits && typeof opts.windowBits === 'number') {
+    windowBits = opts.windowBits;
+  }
+
+  var memLevel = exports.Z_DEFAULT_MEMLEVEL;
+  if (opts.memLevel && typeof opts.memLevel === 'number') {
+    memLevel = opts.memLevel;
+  }
+
+  this._handle.init(windowBits,
                     level,
-                    opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
+                    memLevel,
                     strategy,
                     opts.dictionary);
 
diff --git a/src/node_zlib.cc b/src/node_zlib.cc
index 304fbf72fe..66a6a476a7 100644
--- a/src/node_zlib.cc
+++ b/src/node_zlib.cc
@@ -469,16 +469,19 @@ class ZCtx : public AsyncWrap {
         CHECK(0 && "wtf?");
     }
 
-    if (ctx->err_ != Z_OK) {
-      ZCtx::Error(ctx, "Init error");
-    }
-
-
     ctx->dictionary_ = reinterpret_cast<Bytef *>(dictionary);
     ctx->dictionary_len_ = dictionary_len;
 
     ctx->write_in_progress_ = false;
     ctx->init_done_ = true;
+
+    if (ctx->err_ != Z_OK) {
+      if (dictionary != nullptr) {
+        delete[] dictionary;
+        ctx->dictionary_ = nullptr;
+      }
+      ctx->env()->ThrowError("Init error");
+    }
   }
 
   static void SetDictionary(ZCtx* ctx) {