summaryrefslogtreecommitdiff
path: root/bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md
diff options
context:
space:
mode:
Diffstat (limited to 'bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md')
-rw-r--r--bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md586
1 files changed, 586 insertions, 0 deletions
diff --git a/bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md b/bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md
new file mode 100644
index 00000000..356e3519
--- /dev/null
+++ b/bin/wiki/ImportarDesdeURL/node_modules/safe-buffer/README.md
@@ -0,0 +1,586 @@
+# safe-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![downloads][downloads-image]][downloads-url] [![javascript style guide][standard-image]][standard-url]
+
+[travis-image]: https://img.shields.io/travis/feross/safe-buffer/master.svg
+[travis-url]: https://travis-ci.org/feross/safe-buffer
+[npm-image]: https://img.shields.io/npm/v/safe-buffer.svg
+[npm-url]: https://npmjs.org/package/safe-buffer
+[downloads-image]: https://img.shields.io/npm/dm/safe-buffer.svg
+[downloads-url]: https://npmjs.org/package/safe-buffer
+[standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg
+[standard-url]: https://standardjs.com
+
+#### Safer Node.js Buffer API
+
+**Use the new Node.js Buffer APIs (`Buffer.from`, `Buffer.alloc`,
+`Buffer.allocUnsafe`, `Buffer.allocUnsafeSlow`) in all versions of Node.js.**
+
+**Uses the built-in implementation when available.**
+
+## install
+
+```
+npm install safe-buffer
+```
+
+[Get supported safe-buffer with the Tidelift Subscription](https://tidelift.com/subscription/pkg/npm-safe-buffer?utm_source=npm-safe-buffer&utm_medium=referral&utm_campaign=readme)
+
+## usage
+
+The goal of this package is to provide a safe replacement for the node.js `Buffer`.
+
+It's a drop-in replacement for `Buffer`. You can use it by adding one `require` line to
+the top of your node.js modules:
+
+```js
+var Buffer = require('safe-buffer').Buffer
+
+// Existing buffer code will continue to work without issues:
+
+new Buffer('hey', 'utf8')
+new Buffer([1, 2, 3], 'utf8')
+new Buffer(obj)
+new Buffer(16) // create an uninitialized buffer (potentially unsafe)
+
+// But you can use these new explicit APIs to make clear what you want:
+
+Buffer.from('hey', 'utf8') // convert from many types to a Buffer
+Buffer.alloc(16) // create a zero-filled buffer (safe)
+Buffer.allocUnsafe(16) // create an uninitialized buffer (potentially unsafe)
+```
+
+## api
+
+### Class Method: Buffer.from(array)
+<!-- YAML
+added: v3.0.0
+-->
+
+* `array` {Array}
+
+Allocates a new `Buffer` using an `array` of octets.
+
+```js
+const buf = Buffer.from([0x62,0x75,0x66,0x66,0x65,0x72]);
+ // creates a new Buffer containing ASCII bytes
+ // ['b','u','f','f','e','r']
+```
+
+A `TypeError` will be thrown if `array` is not an `Array`.
+
+### Class Method: Buffer.from(arrayBuffer[, byteOffset[, length]])
+<!-- YAML
+added: v5.10.0
+-->
+
+* `arrayBuffer` {ArrayBuffer} The `.buffer` property of a `TypedArray` or
+ a `new ArrayBuffer()`
+* `byteOffset` {Number} Default: `0`
+* `length` {Number} Default: `arrayBuffer.length - byteOffset`
+
+When passed a reference to the `.buffer` property of a `TypedArray` instance,
+the newly created `Buffer` will share the same allocated memory as the
+TypedArray.
+
+```js
+const arr = new Uint16Array(2);
+arr[0] = 5000;
+arr[1] = 4000;
+
+const buf = Buffer.from(arr.buffer); // shares the memory with arr;
+
+console.log(buf);
+ // Prints: <Buffer 88 13 a0 0f>
+
+// changing the TypedArray changes the Buffer also
+arr[1] = 6000;
+
+console.log(buf);
+ // Prints: <Buffer 88 13 70 17>
+```
+
+The optional `byteOffset` and `length` arguments specify a memory range within
+the `arrayBuffer` that will be shared by the `Buffer`.
+
+```js
+const ab = new ArrayBuffer(10);
+const buf = Buffer.from(ab, 0, 2);
+console.log(buf.length);
+ // Prints: 2
+```
+
+A `TypeError` will be thrown if `arrayBuffer` is not an `ArrayBuffer`.
+
+### Class Method: Buffer.from(buffer)
+<!-- YAML
+added: v3.0.0
+-->
+
+* `buffer` {Buffer}
+
+Copies the passed `buffer` data onto a new `Buffer` instance.
+
+```js
+const buf1 = Buffer.from('buffer');
+const buf2 = Buffer.from(buf1);
+
+buf1[0] = 0x61;
+console.log(buf1.toString());
+ // 'auffer'
+console.log(buf2.toString());
+ // 'buffer' (copy is not changed)
+```
+
+A `TypeError` will be thrown if `buffer` is not a `Buffer`.
+
+### Class Method: Buffer.from(str[, encoding])
+<!-- YAML
+added: v5.10.0
+-->
+
+* `str` {String} String to encode.
+* `encoding` {String} Encoding to use, Default: `'utf8'`
+
+Creates a new `Buffer` containing the given JavaScript string `str`. If
+provided, the `encoding` parameter identifies the character encoding.
+If not provided, `encoding` defaults to `'utf8'`.
+
+```js
+const buf1 = Buffer.from('this is a tést');
+console.log(buf1.toString());
+ // prints: this is a tést
+console.log(buf1.toString('ascii'));
+ // prints: this is a tC)st
+
+const buf2 = Buffer.from('7468697320697320612074c3a97374', 'hex');
+console.log(buf2.toString());
+ // prints: this is a tést
+```
+
+A `TypeError` will be thrown if `str` is not a string.
+
+### Class Method: Buffer.alloc(size[, fill[, encoding]])
+<!-- YAML
+added: v5.10.0
+-->
+
+* `size` {Number}
+* `fill` {Value} Default: `undefined`
+* `encoding` {String} Default: `utf8`
+
+Allocates a new `Buffer` of `size` bytes. If `fill` is `undefined`, the
+`Buffer` will be *zero-filled*.
+
+```js
+const buf = Buffer.alloc(5);
+console.log(buf);
+ // <Buffer 00 00 00 00 00>
+```
+
+The `size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+If `fill` is specified, the allocated `Buffer` will be initialized by calling
+`buf.fill(fill)`. See [`buf.fill()`][] for more information.
+
+```js
+const buf = Buffer.alloc(5, 'a');
+console.log(buf);
+ // <Buffer 61 61 61 61 61>
+```
+
+If both `fill` and `encoding` are specified, the allocated `Buffer` will be
+initialized by calling `buf.fill(fill, encoding)`. For example:
+
+```js
+const buf = Buffer.alloc(11, 'aGVsbG8gd29ybGQ=', 'base64');
+console.log(buf);
+ // <Buffer 68 65 6c 6c 6f 20 77 6f 72 6c 64>
+```
+
+Calling `Buffer.alloc(size)` can be significantly slower than the alternative
+`Buffer.allocUnsafe(size)` but ensures that the newly created `Buffer` instance
+contents will *never contain sensitive data*.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### Class Method: Buffer.allocUnsafe(size)
+<!-- YAML
+added: v5.10.0
+-->
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* `Buffer` of `size` bytes. The `size` must
+be less than or equal to the value of `require('buffer').kMaxLength` (on 64-bit
+architectures, `kMaxLength` is `(2^31)-1`). Otherwise, a [`RangeError`][] is
+thrown. A zero-length Buffer will be created if a `size` less than or equal to
+0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+```js
+const buf = Buffer.allocUnsafe(5);
+console.log(buf);
+ // <Buffer 78 e0 82 02 01>
+ // (octets will be different, every time)
+buf.fill(0);
+console.log(buf);
+ // <Buffer 00 00 00 00 00>
+```
+
+A `TypeError` will be thrown if `size` is not a number.
+
+Note that the `Buffer` module pre-allocates an internal `Buffer` instance of
+size `Buffer.poolSize` that is used as a pool for the fast allocation of new
+`Buffer` instances created using `Buffer.allocUnsafe(size)` (and the deprecated
+`new Buffer(size)` constructor) only when `size` is less than or equal to
+`Buffer.poolSize >> 1` (floor of `Buffer.poolSize` divided by two). The default
+value of `Buffer.poolSize` is `8192` but can be modified.
+
+Use of this pre-allocated internal memory pool is a key difference between
+calling `Buffer.alloc(size, fill)` vs. `Buffer.allocUnsafe(size).fill(fill)`.
+Specifically, `Buffer.alloc(size, fill)` will *never* use the internal Buffer
+pool, while `Buffer.allocUnsafe(size).fill(fill)` *will* use the internal
+Buffer pool if `size` is less than or equal to half `Buffer.poolSize`. The
+difference is subtle but can be important when an application requires the
+additional performance that `Buffer.allocUnsafe(size)` provides.
+
+### Class Method: Buffer.allocUnsafeSlow(size)
+<!-- YAML
+added: v5.10.0
+-->
+
+* `size` {Number}
+
+Allocates a new *non-zero-filled* and non-pooled `Buffer` of `size` bytes. The
+`size` must be less than or equal to the value of
+`require('buffer').kMaxLength` (on 64-bit architectures, `kMaxLength` is
+`(2^31)-1`). Otherwise, a [`RangeError`][] is thrown. A zero-length Buffer will
+be created if a `size` less than or equal to 0 is specified.
+
+The underlying memory for `Buffer` instances created in this way is *not
+initialized*. The contents of the newly created `Buffer` are unknown and
+*may contain sensitive data*. Use [`buf.fill(0)`][] to initialize such
+`Buffer` instances to zeroes.
+
+When using `Buffer.allocUnsafe()` to allocate new `Buffer` instances,
+allocations under 4KB are, by default, sliced from a single pre-allocated
+`Buffer`. This allows applications to avoid the garbage collection overhead of
+creating many individually allocated Buffers. This approach improves both
+performance and memory usage by eliminating the need to track and cleanup as
+many `Persistent` objects.
+
+However, in the case where a developer may need to retain a small chunk of
+memory from a pool for an indeterminate amount of time, it may be appropriate
+to create an un-pooled Buffer instance using `Buffer.allocUnsafeSlow()` then
+copy out the relevant bits.
+
+```js
+// need to keep around a few small chunks of memory
+const store = [];
+
+socket.on('readable', () => {
+ const data = socket.read();
+ // allocate for retained data
+ const sb = Buffer.allocUnsafeSlow(10);
+ // copy the data into the new allocation
+ data.copy(sb, 0, 0, 10);
+ store.push(sb);
+});
+```
+
+Use of `Buffer.allocUnsafeSlow()` should be used only as a last resort *after*
+a developer has observed undue memory retention in their applications.
+
+A `TypeError` will be thrown if `size` is not a number.
+
+### All the Rest
+
+The rest of the `Buffer` API is exactly the same as in node.js.
+[See the docs](https://nodejs.org/api/buffer.html).
+
+
+## Related links
+
+- [Node.js issue: Buffer(number) is unsafe](https://github.com/nodejs/node/issues/4660)
+- [Node.js Enhancement Proposal: Buffer.from/Buffer.alloc/Buffer.zalloc/Buffer() soft-deprecate](https://github.com/nodejs/node-eps/pull/4)
+
+## Why is `Buffer` unsafe?
+
+Today, the node.js `Buffer` constructor is overloaded to handle many different argument
+types like `String`, `Array`, `Object`, `TypedArrayView` (`Uint8Array`, etc.),
+`ArrayBuffer`, and also `Number`.
+
+The API is optimized for convenience: you can throw any type at it, and it will try to do
+what you want.
+
+Because the Buffer constructor is so powerful, you often see code like this:
+
+```js
+// Convert UTF-8 strings to hex
+function toHex (str) {
+ return new Buffer(str).toString('hex')
+}
+```
+
+***But what happens if `toHex` is called with a `Number` argument?***
+
+### Remote Memory Disclosure
+
+If an attacker can make your program call the `Buffer` constructor with a `Number`
+argument, then they can make it allocate uninitialized memory from the node.js process.
+This could potentially disclose TLS private keys, user data, or database passwords.
+
+When the `Buffer` constructor is passed a `Number` argument, it returns an
+**UNINITIALIZED** block of memory of the specified `size`. When you create a `Buffer` like
+this, you **MUST** overwrite the contents before returning it to the user.
+
+From the [node.js docs](https://nodejs.org/api/buffer.html#buffer_new_buffer_size):
+
+> `new Buffer(size)`
+>
+> - `size` Number
+>
+> The underlying memory for `Buffer` instances created in this way is not initialized.
+> **The contents of a newly created `Buffer` are unknown and could contain sensitive
+> data.** Use `buf.fill(0)` to initialize a Buffer to zeroes.
+
+(Emphasis our own.)
+
+Whenever the programmer intended to create an uninitialized `Buffer` you often see code
+like this:
+
+```js
+var buf = new Buffer(16)
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+ buf[i] = otherBuf[i]
+}
+```
+
+
+### Would this ever be a problem in real code?
+
+Yes. It's surprisingly common to forget to check the type of your variables in a
+dynamically-typed language like JavaScript.
+
+Usually the consequences of assuming the wrong type is that your program crashes with an
+uncaught exception. But the failure mode for forgetting to check the type of arguments to
+the `Buffer` constructor is more catastrophic.
+
+Here's an example of a vulnerable service that takes a JSON payload and converts it to
+hex:
+
+```js
+// Take a JSON payload {str: "some string"} and convert it to hex
+var server = http.createServer(function (req, res) {
+ var data = ''
+ req.setEncoding('utf8')
+ req.on('data', function (chunk) {
+ data += chunk
+ })
+ req.on('end', function () {
+ var body = JSON.parse(data)
+ res.end(new Buffer(body.str).toString('hex'))
+ })
+})
+
+server.listen(8080)
+```
+
+In this example, an http client just has to send:
+
+```json
+{
+ "str": 1000
+}
+```
+
+and it will get back 1,000 bytes of uninitialized memory from the server.
+
+This is a very serious bug. It's similar in severity to the
+[the Heartbleed bug](http://heartbleed.com/) that allowed disclosure of OpenSSL process
+memory by remote attackers.
+
+
+### Which real-world packages were vulnerable?
+
+#### [`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht)
+
+[Mathias Buus](https://github.com/mafintosh) and I
+([Feross Aboukhadijeh](http://feross.org/)) found this issue in one of our own packages,
+[`bittorrent-dht`](https://www.npmjs.com/package/bittorrent-dht). The bug would allow
+anyone on the internet to send a series of messages to a user of `bittorrent-dht` and get
+them to reveal 20 bytes at a time of uninitialized memory from the node.js process.
+
+Here's
+[the commit](https://github.com/feross/bittorrent-dht/commit/6c7da04025d5633699800a99ec3fbadf70ad35b8)
+that fixed it. We released a new fixed version, created a
+[Node Security Project disclosure](https://nodesecurity.io/advisories/68), and deprecated all
+vulnerable versions on npm so users will get a warning to upgrade to a newer version.
+
+#### [`ws`](https://www.npmjs.com/package/ws)
+
+That got us wondering if there were other vulnerable packages. Sure enough, within a short
+period of time, we found the same issue in [`ws`](https://www.npmjs.com/package/ws), the
+most popular WebSocket implementation in node.js.
+
+If certain APIs were called with `Number` parameters instead of `String` or `Buffer` as
+expected, then uninitialized server memory would be disclosed to the remote peer.
+
+These were the vulnerable methods:
+
+```js
+socket.send(number)
+socket.ping(number)
+socket.pong(number)
+```
+
+Here's a vulnerable socket server with some echo functionality:
+
+```js
+server.on('connection', function (socket) {
+ socket.on('message', function (message) {
+ message = JSON.parse(message)
+ if (message.type === 'echo') {
+ socket.send(message.data) // send back the user's message
+ }
+ })
+})
+```
+
+`socket.send(number)` called on the server, will disclose server memory.
+
+Here's [the release](https://github.com/websockets/ws/releases/tag/1.0.1) where the issue
+was fixed, with a more detailed explanation. Props to
+[Arnout Kazemier](https://github.com/3rd-Eden) for the quick fix. Here's the
+[Node Security Project disclosure](https://nodesecurity.io/advisories/67).
+
+
+### What's the solution?
+
+It's important that node.js offers a fast way to get memory otherwise performance-critical
+applications would needlessly get a lot slower.
+
+But we need a better way to *signal our intent* as programmers. **When we want
+uninitialized memory, we should request it explicitly.**
+
+Sensitive functionality should not be packed into a developer-friendly API that loosely
+accepts many different types. This type of API encourages the lazy practice of passing
+variables in without checking the type very carefully.
+
+#### A new API: `Buffer.allocUnsafe(number)`
+
+The functionality of creating buffers with uninitialized memory should be part of another
+API. We propose `Buffer.allocUnsafe(number)`. This way, it's not part of an API that
+frequently gets user input of all sorts of different types passed into it.
+
+```js
+var buf = Buffer.allocUnsafe(16) // careful, uninitialized memory!
+
+// Immediately overwrite the uninitialized buffer with data from another buffer
+for (var i = 0; i < buf.length; i++) {
+ buf[i] = otherBuf[i]
+}
+```
+
+
+### How do we fix node.js core?
+
+We sent [a PR to node.js core](https://github.com/nodejs/node/pull/4514) (merged as
+`semver-major`) which defends against one case:
+
+```js
+var str = 16
+new Buffer(str, 'utf8')
+```
+
+In this situation, it's implied that the programmer intended the first argument to be a
+string, since they passed an encoding as a second argument. Today, node.js will allocate
+uninitialized memory in the case of `new Buffer(number, encoding)`, which is probably not
+what the programmer intended.
+
+But this is only a partial solution, since if the programmer does `new Buffer(variable)`
+(without an `encoding` parameter) there's no way to know what they intended. If `variable`
+is sometimes a number, then uninitialized memory will sometimes be returned.
+
+### What's the real long-term fix?
+
+We could deprecate and remove `new Buffer(number)` and use `Buffer.allocUnsafe(number)` when
+we need uninitialized memory. But that would break 1000s of packages.
+
+~~We believe the best solution is to:~~
+
+~~1. Change `new Buffer(number)` to return safe, zeroed-out memory~~
+
+~~2. Create a new API for creating uninitialized Buffers. We propose: `Buffer.allocUnsafe(number)`~~
+
+#### Update
+
+We now support adding three new APIs:
+
+- `Buffer.from(value)` - convert from any type to a buffer
+- `Buffer.alloc(size)` - create a zero-filled buffer
+- `Buffer.allocUnsafe(size)` - create an uninitialized buffer with given size
+
+This solves the core problem that affected `ws` and `bittorrent-dht` which is
+`Buffer(variable)` getting tricked into taking a number argument.
+
+This way, existing code continues working and the impact on the npm ecosystem will be
+minimal. Over time, npm maintainers can migrate performance-critical code to use
+`Buffer.allocUnsafe(number)` instead of `new Buffer(number)`.
+
+
+### Conclusion
+
+We think there's a serious design issue with the `Buffer` API as it exists today. It
+promotes insecure software by putting high-risk functionality into a convenient API
+with friendly "developer ergonomics".
+
+This wasn't merely a theoretical exercise because we found the issue in some of the
+most popular npm packages.
+
+Fortunately, there's an easy fix that can be applied today. Use `safe-buffer` in place of
+`buffer`.
+
+```js
+var Buffer = require('safe-buffer').Buffer
+```
+
+Eventually, we hope that node.js core can switch to this new, safer behavior. We believe
+the impact on the ecosystem would be minimal since it's not a breaking change.
+Well-maintained, popular packages would be updated to use `Buffer.alloc` quickly, while
+older, insecure packages would magically become safe from this attack vector.
+
+
+## links
+
+- [Node.js PR: buffer: throw if both length and enc are passed](https://github.com/nodejs/node/pull/4514)
+- [Node Security Project disclosure for `ws`](https://nodesecurity.io/advisories/67)
+- [Node Security Project disclosure for`bittorrent-dht`](https://nodesecurity.io/advisories/68)
+
+
+## credit
+
+The original issues in `bittorrent-dht`
+([disclosure](https://nodesecurity.io/advisories/68)) and
+`ws` ([disclosure](https://nodesecurity.io/advisories/67)) were discovered by
+[Mathias Buus](https://github.com/mafintosh) and
+[Feross Aboukhadijeh](http://feross.org/).
+
+Thanks to [Adam Baldwin](https://github.com/evilpacket) for helping disclose these issues
+and for his work running the [Node Security Project](https://nodesecurity.io/).
+
+Thanks to [John Hiesey](https://github.com/jhiesey) for proofreading this README and
+auditing the code.
+
+
+## license
+
+MIT. Copyright (C) [Feross Aboukhadijeh](http://feross.org)