zlib: fix raw inflate with custom dictionary

Moves inflateSetDictionary right after inflateInit2 when mode is
INFLATERAW, since without the wrapper in appears zlib won't return
Z_NEED_DICT as it would otherwise, and will thus attempt inflating
without the dictionary, leading to an error.

Fixes: https://github.com/nodejs/node/issues/8507
PR-URL: https://github.com/nodejs/node/pull/8512
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node_zlib.cc

@@ -282,8 +282,11 @@ class ZCtx : public AsyncWrap {
       case INFLATERAW:
         ctx->err_ = inflate(&ctx->strm_, ctx->flush_);
 
-        // If data was encoded with dictionary
-        if (ctx->err_ == Z_NEED_DICT && ctx->dictionary_ != nullptr) {
+        // If data was encoded with dictionary (INFLATERAW will have it set in
+        // SetDictionary, don't repeat that here)
+        if (ctx->mode_ != INFLATERAW &&
+            ctx->err_ == Z_NEED_DICT &&
+            ctx->dictionary_ != nullptr) {
           // Load it
           ctx->err_ = inflateSetDictionary(&ctx->strm_,
                                            ctx->dictionary_,
@@ -552,6 +555,13 @@ class ZCtx : public AsyncWrap {
                                          ctx->dictionary_,
                                          ctx->dictionary_len_);
         break;
+      case INFLATERAW:
+        // The other inflate cases will have the dictionary set when inflate()
+        // returns Z_NEED_DICT in Process()
+        ctx->err_ = inflateSetDictionary(&ctx->strm_,
+                                         ctx->dictionary_,
+                                         ctx->dictionary_len_);
+        break;
       default:
         break;
     }

test/parallel/test-zlib-dictionary-fail.js

@@ -26,3 +26,17 @@ const zlib = require('zlib');
   // String "test" encoded with dictionary "dict".
   stream.write(Buffer.from([0x78, 0xBB, 0x04, 0x09, 0x01, 0xA5]));
 }
+
+// Should raise an error, not trigger an assertion in src/node_zlib.cc
+{
+  const stream = zlib.createInflateRaw({ dictionary: Buffer.from('fail') });
+
+  stream.on('error', common.mustCall(function(err) {
+    // It's not possible to separate invalid dict and invalid data when using
+    // the raw format
+    assert(/invalid/.test(err.message));
+  }));
+
+  // String "test" encoded with dictionary "dict".
+  stream.write(Buffer.from([0x78, 0xBB, 0x04, 0x09, 0x01, 0xA5]));
+}

test/parallel/test-zlib-dictionary.js

@@ -85,5 +85,64 @@ function deflateResetDictionaryTest() {
   });
 }
 
+function rawDictionaryTest() {
+  let output = '';
+  const deflate = zlib.createDeflateRaw({ dictionary: spdyDict });
+  const inflate = zlib.createInflateRaw({ dictionary: spdyDict });
+
+  deflate.on('data', function(chunk) {
+    inflate.write(chunk);
+  });
+
+  inflate.on('data', function(chunk) {
+    output += chunk;
+  });
+
+  deflate.on('end', function() {
+    inflate.end();
+  });
+
+  inflate.on('end', function() {
+    assert.equal(input, output);
+  });
+
+  deflate.write(input);
+  deflate.end();
+}
+
+function deflateRawResetDictionaryTest() {
+  let doneReset = false;
+  let output = '';
+  const deflate = zlib.createDeflateRaw({ dictionary: spdyDict });
+  const inflate = zlib.createInflateRaw({ dictionary: spdyDict });
+
+  deflate.on('data', function(chunk) {
+    if (doneReset)
+      inflate.write(chunk);
+  });
+
+  inflate.on('data', function(chunk) {
+    output += chunk;
+  });
+
+  deflate.on('end', function() {
+    inflate.end();
+  });
+
+  inflate.on('end', function() {
+    assert.equal(input, output);
+  });
+
+  deflate.write(input);
+  deflate.flush(function() {
+    deflate.reset();
+    doneReset = true;
+    deflate.write(input);
+    deflate.end();
+  });
+}
+
 basicDictionaryTest();
 deflateResetDictionaryTest();
+rawDictionaryTest();
+deflateRawResetDictionaryTest();