zlib: expose rejectGarbageAfterEnd option

Document rejectGarbageAfterEnd as a public decompression option and
validate it as a boolean.
Add coverage for stream, async convenience, and sync convenience APIs
across zlib, gzip, Brotli, and Zstd-backed decompression.
Signed-off-by: Filip Skokan <panva.ip@gmail.com>
PR-URL: #64023Fixes: #58247
Reviewed-By: Anna Henningsen <anna@addaleax.net>

Author: panva

doc/api/zlib.md

@@ -803,6 +803,9 @@ These advanced options are available for controlling decompression:
 <!-- YAML
 added: v0.11.1
 changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/64023
+ description: The `rejectGarbageAfterEnd` option was added.
  - version:
  - v14.5.0
  - v12.19.0
@@ -838,6 +841,10 @@ ignored by the decompression classes.
 *`info` {boolean} (If `true`, returns an object with `buffer` and `engine`.)
 *`maxOutputLength` {integer} Limits output size when using
 [convenience methods][]. **Default:**[`buffer.kMaxLength`][]
+*`rejectGarbageAfterEnd` {boolean} If `true`, decompression fails when
+ trailing input is detected after the end of the compressed stream. This
+ includes unreadable bytes and, when decompressing gzip, additional gzip
+ members following the first member. **Default:**`false`
 
 See the [`deflateInit2` and `inflateInit2`][] documentation for more
 information.
@@ -847,6 +854,9 @@ information.
 <!-- YAML
 added: v11.7.0
 changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/64023
+ description: The `rejectGarbageAfterEnd` option was added.
  - version:
  - v14.5.0
  - v12.19.0
@@ -865,6 +875,8 @@ Each Brotli-based class takes an `options` object. All options are optional.
 *`maxOutputLength` {integer} Limits output size when using
 [convenience methods][]. **Default:**[`buffer.kMaxLength`][]
 *`info` {boolean} If `true`, returns an object with `buffer` and `engine`. **Default:**`false`
+*`rejectGarbageAfterEnd` {boolean} If `true`, decompression fails when
+ input remains after the first complete compressed stream. **Default:**`false`
 
 For example:
 
@@ -1088,6 +1100,10 @@ the inflate and deflate algorithms.
 added:
  - v23.8.0
  - v22.15.0
+changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/64023
+ description: The `rejectGarbageAfterEnd` option was added.
 -->
 
 <!--type=misc-->
@@ -1104,6 +1120,8 @@ Each Zstd-based class takes an `options` object. All options are optional.
 *`dictionary` {Buffer} Optional dictionary used to
  improve compression efficiency when compressing or decompressing data that
  shares common patterns with the dictionary.
+*`rejectGarbageAfterEnd` {boolean} If `true`, decompression fails when
+ input remains after the first complete compressed stream. **Default:**`false`
 
 For example:
 

lib/zlib.js

@@ -65,6 +65,7 @@ const {
 const{ owner_symbol }=require('internal/async_hooks').symbols;
 const{
  checkRangesOrGetDefault,
+ validateBoolean,
  validateFunction,
  validateUint32,
  validateFiniteNumber,
@@ -246,6 +247,13 @@ function ZlibBase(opts, mode, handle, { flush, finishFlush, fullFlush }) {
 opts.maxOutputLength,'options.maxOutputLength',
 1,kMaxLength,kMaxLength);
 
+if(opts.rejectGarbageAfterEnd!==undefined){
+validateBoolean(
+opts.rejectGarbageAfterEnd,
+'options.rejectGarbageAfterEnd',
+);
+}
+
 if(opts.encoding||opts.objectMode||opts.writableObjectMode){
 opts={ ...opts};
 opts.encoding=null;

test/parallel/test-zlib-reject-garbage-after-end.js

@@ -0,0 +1,144 @@
+'use strict';
+
+require('../common');
+constassert=require('assert');
+consttest=require('node:test');
+const{ finished }=require('stream/promises');
+constzlib=require('zlib');
+
+consttrailingJunkError={
+code: 'ERR_TRAILING_JUNK_AFTER_STREAM_END',
+name: 'TypeError',
+};
+
+functioncallAsync(fn,input,options){
+returnnewPromise((resolve,reject)=>{
+fn(input,options,(err,result)=>{
+if(err){
+reject(err);
+}else{
+resolve(result);
+}
+});
+});
+}
+
+asyncfunctioncollect(stream,input){
+constchunks=[];
+stream.on('data',(chunk)=>chunks.push(chunk));
+stream.end(input);
+awaitfinished(stream);
+returnBuffer.concat(chunks);
+}
+
+constcases=[
+{
+label: 'inflate',
+compress: zlib.deflateSync,
+decompress: zlib.inflate,
+decompressSync: zlib.inflateSync,
+createDecompress: zlib.createInflate,
+defaultOutput: 'a',
+},
+{
+label: 'inflateRaw',
+compress: zlib.deflateRawSync,
+decompress: zlib.inflateRaw,
+decompressSync: zlib.inflateRawSync,
+createDecompress: zlib.createInflateRaw,
+defaultOutput: 'a',
+},
+{
+label: 'gunzip',
+compress: zlib.gzipSync,
+decompress: zlib.gunzip,
+decompressSync: zlib.gunzipSync,
+createDecompress: zlib.createGunzip,
+defaultOutput: 'aa',
+},
+{
+label: 'unzip',
+compress: zlib.gzipSync,
+decompress: zlib.unzip,
+decompressSync: zlib.unzipSync,
+createDecompress: zlib.createUnzip,
+defaultOutput: 'aa',
+},
+{
+label: 'brotli',
+compress: zlib.brotliCompressSync,
+decompress: zlib.brotliDecompress,
+decompressSync: zlib.brotliDecompressSync,
+createDecompress: zlib.createBrotliDecompress,
+defaultOutput: 'a',
+},
+{
+label: 'zstd',
+compress: zlib.zstdCompressSync,
+decompress: zlib.zstdDecompress,
+decompressSync: zlib.zstdDecompressSync,
+createDecompress: zlib.createZstdDecompress,
+defaultOutput: 'a',
+},
+];
+
+for(const{
+ label,
+ compress,
+ decompress,
+ decompressSync,
+ createDecompress,
+ defaultOutput,
+}ofcases){
+test(`rejectGarbageAfterEnd rejects trailing input for ${label}`,async()=>{
+constcompressed=compress(Buffer.from('a'));
+constwithTrailingInput=Buffer.concat([compressed,compressed]);
+
+assert.strictEqual(decompressSync(withTrailingInput).toString(),defaultOutput);
+assert.strictEqual(
+(awaitcallAsync(decompress,withTrailingInput)).toString(),
+defaultOutput,
+);
+assert.strictEqual(
+(awaitcollect(createDecompress(),withTrailingInput)).toString(),
+defaultOutput,
+);
+
+assert.throws(
+()=>decompressSync(withTrailingInput,{rejectGarbageAfterEnd: true}),
+trailingJunkError,
+);
+awaitassert.rejects(
+callAsync(decompress,withTrailingInput,{rejectGarbageAfterEnd: true}),
+trailingJunkError,
+);
+awaitassert.rejects(
+collect(
+createDecompress({rejectGarbageAfterEnd: true}),
+withTrailingInput,
+),
+trailingJunkError,
+);
+});
+}
+
+test('rejectGarbageAfterEnd must be a boolean',()=>{
+constcompressed=zlib.deflateSync(Buffer.from('a'));
+
+for(constvalueof[1,'true',null]){
+assert.throws(
+()=>zlib.inflateSync(compressed,{rejectGarbageAfterEnd: value}),
+{
+code: 'ERR_INVALID_ARG_TYPE',
+name: 'TypeError',
+},
+);
+assert.throws(
+()=>zlib.createInflate({rejectGarbageAfterEnd: value}),
+{
+code: 'ERR_INVALID_ARG_TYPE',
+name: 'TypeError',
+},
+);
+}
+});