diff options
author | Myles Borins <mylesborins@google.com> | 2017-10-13 08:10:44 +0300 |
---|---|---|
committer | Myles Borins <mylesborins@google.com> | 2017-10-24 18:02:19 +0300 |
commit | f5defa2a7cc20993d2d4206e8b74930e87e8f18d (patch) | |
tree | 6bdd80fd1ba689a3c5d95fc6238a7bf39ee329e8 | |
parent | d3a40c51c5770b4def9a6033df0fa46c6f9f0cc7 (diff) |
zlib: gracefully set windowBits from 8 to 9
On 4 April 2017, Node.js versions v4.8.2 and v6.10.2 were
released. These versions bumped the vendored zlib library from
v1.2.8 to v1.2.11 in response to what it describes as low-severity
CVEs. In zlib v1.2.9, a change was made that causes an error to be
raised when a raw deflate stream is initialised with windowBits set
to 8.
In zlib v1.2.9, 8 become an invalid value for this parameter, and Node's zlib
module will crash if you call this:
```
zlib.createDeflateRaw({windowBits: 8})
```
On some versions this crashes Node and you cannot recover from it, while on some
versions it throws an exception. The permessage-deflate library up to
version v0.1.5 does make such a call with no try/catch
This commit reverts to the original behavior of zlib by gracefully changed
windowBits: 8 to windowBits: 9 for raw deflate streams.
PR-URL: https://github.com/nodejs-private/node-private/pull/95
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
-rw-r--r-- | doc/api/zlib.md | 8 | ||||
-rw-r--r-- | lib/zlib.js | 1 | ||||
-rw-r--r-- | test/parallel/test-zlib.js | 22 |
3 files changed, 31 insertions, 0 deletions
diff --git a/doc/api/zlib.md b/doc/api/zlib.md index 8e5f14621b9..b0ea5146452 100644 --- a/doc/api/zlib.md +++ b/doc/api/zlib.md @@ -373,6 +373,14 @@ added: v0.5.8 Returns a new [DeflateRaw][] object with an [options][]. +*Note*: An upgrade of zlib from 1.2.8 to 1.2.11 changed behavior when windowBits +is set to 8 for raw deflate streams. zlib does not have a working implementation +of an 8-bit Window for raw deflate streams and would automatically set windowBit +to 9 if initially set to 8. Newer versions of zlib will throw an exception. +This creates a potential DOS vector, and as such the behavior ahs been reverted +in Node.js 8, 6, and 4. Node.js version 9 and higher will throw when windowBits +is set to 8. + ## zlib.createGunzip([options]) <!-- YAML added: v0.5.8 diff --git a/lib/zlib.js b/lib/zlib.js index ecddfda653f..079c413e2f9 100644 --- a/lib/zlib.js +++ b/lib/zlib.js @@ -266,6 +266,7 @@ function Gunzip(opts) { // raw - no header function DeflateRaw(opts) { + if (opts && opts.windowBits === 8) opts.windowBits = 9; if (!(this instanceof DeflateRaw)) return new DeflateRaw(opts); Zlib.call(this, opts, binding.DEFLATERAW); } diff --git a/test/parallel/test-zlib.js b/test/parallel/test-zlib.js index 13f1a2776ad..392fc5feadf 100644 --- a/test/parallel/test-zlib.js +++ b/test/parallel/test-zlib.js @@ -131,6 +131,28 @@ SlowStream.prototype.end = function(chunk) { return this.ended; }; +// windowBits: 8 shouldn't throw +assert.doesNotThrow(() => { + zlib.createDeflateRaw({ windowBits: 8 }); +}, 'windowsBits set to 8 should follow legacy zlib behavior'); + +{ + const node = fs.createReadStream(process.execPath); + const raw = []; + const reinflated = []; + node.on('data', (chunk) => raw.push(chunk)); + + // Usually, the inflate windowBits parameter needs to be at least the + // value of the matching deflateās windowBits. However, inflate raw with + // windowBits = 8 should be able to handle compressed data from a source + // that does not know about the silent 8-to-9 upgrade of windowBits + // that older versions of zlib/Node perform. + node.pipe(zlib.createDeflateRaw({ windowBits: 9 })) + .pipe(zlib.createInflateRaw({ windowBits: 8 })) + .on('data', (chunk) => reinflated.push(chunk)) + .on('end', common.mustCall( + () => assert(Buffer.concat(raw).equals(Buffer.concat(reinflated))))); +} // for each of the files, make sure that compressing and // decompressing results in the same data, for every combination |