Readme.md (8261B)
1 # safer-buffer [![travis][travis-image]][travis-url] [![npm][npm-image]][npm-url] [![javascript style guide][standard-image]][standard-url] [![Security Responsible Disclosure][secuirty-image]][secuirty-url] 2 3 [travis-image]: https://travis-ci.org/ChALkeR/safer-buffer.svg?branch=master 4 [travis-url]: https://travis-ci.org/ChALkeR/safer-buffer 5 [npm-image]: https://img.shields.io/npm/v/safer-buffer.svg 6 [npm-url]: https://npmjs.org/package/safer-buffer 7 [standard-image]: https://img.shields.io/badge/code_style-standard-brightgreen.svg 8 [standard-url]: https://standardjs.com 9 [secuirty-image]: https://img.shields.io/badge/Security-Responsible%20Disclosure-green.svg 10 [secuirty-url]: https://github.com/nodejs/security-wg/blob/master/processes/responsible_disclosure_template.md 11 12 Modern Buffer API polyfill without footguns, working on Node.js from 0.8 to current. 13 14 ## How to use? 15 16 First, port all `Buffer()` and `new Buffer()` calls to `Buffer.alloc()` and `Buffer.from()` API. 17 18 Then, to achieve compatibility with outdated Node.js versions (`<4.5.0` and 5.x `<5.9.0`), use 19 `const Buffer = require('safer-buffer').Buffer` in all files where you make calls to the new 20 Buffer API. _Use `var` instead of `const` if you need that for your Node.js version range support._ 21 22 Also, see the 23 [porting Buffer](https://github.com/ChALkeR/safer-buffer/blob/master/Porting-Buffer.md) guide. 24 25 ## Do I need it? 26 27 Hopefully, not — dropping support for outdated Node.js versions should be fine nowdays, and that 28 is the recommended path forward. You _do_ need to port to the `Buffer.alloc()` and `Buffer.from()` 29 though. 30 31 See the [porting guide](https://github.com/ChALkeR/safer-buffer/blob/master/Porting-Buffer.md) 32 for a better description. 33 34 ## Why not [safe-buffer](https://npmjs.com/safe-buffer)? 35 36 _In short: while `safe-buffer` serves as a polyfill for the new API, it allows old API usage and 37 itself contains footguns._ 38 39 `safe-buffer` could be used safely to get the new API while still keeping support for older 40 Node.js versions (like this module), but while analyzing ecosystem usage of the old Buffer API 41 I found out that `safe-buffer` is itself causing problems in some cases. 42 43 For example, consider the following snippet: 44 45 ```console 46 $ cat example.unsafe.js 47 console.log(Buffer(20)) 48 $ ./node-v6.13.0-linux-x64/bin/node example.unsafe.js 49 <Buffer 0a 00 00 00 00 00 00 00 28 13 de 02 00 00 00 00 05 00 00 00> 50 $ standard example.unsafe.js 51 standard: Use JavaScript Standard Style (https://standardjs.com) 52 /home/chalker/repo/safer-buffer/example.unsafe.js:2:13: 'Buffer()' was deprecated since v6. Use 'Buffer.alloc()' or 'Buffer.from()' (use 'https://www.npmjs.com/package/safe-buffer' for '<4.5.0') instead. 53 ``` 54 55 This is allocates and writes to console an uninitialized chunk of memory. 56 [standard](https://www.npmjs.com/package/standard) linter (among others) catch that and warn people 57 to avoid using unsafe API. 58 59 Let's now throw in `safe-buffer`! 60 61 ```console 62 $ cat example.safe-buffer.js 63 const Buffer = require('safe-buffer').Buffer 64 console.log(Buffer(20)) 65 $ standard example.safe-buffer.js 66 $ ./node-v6.13.0-linux-x64/bin/node example.safe-buffer.js 67 <Buffer 08 00 00 00 00 00 00 00 28 58 01 82 fe 7f 00 00 00 00 00 00> 68 ``` 69 70 See the problem? Adding in `safe-buffer` _magically removes the lint warning_, but the behavior 71 remains identiсal to what we had before, and when launched on Node.js 6.x LTS — this dumps out 72 chunks of uninitialized memory. 73 _And this code will still emit runtime warnings on Node.js 10.x and above._ 74 75 That was done by design. I first considered changing `safe-buffer`, prohibiting old API usage or 76 emitting warnings on it, but that significantly diverges from `safe-buffer` design. After some 77 discussion, it was decided to move my approach into a separate package, and _this is that separate 78 package_. 79 80 This footgun is not imaginary — I observed top-downloaded packages doing that kind of thing, 81 «fixing» the lint warning by blindly including `safe-buffer` without any actual changes. 82 83 Also in some cases, even if the API _was_ migrated to use of safe Buffer API — a random pull request 84 can bring unsafe Buffer API usage back to the codebase by adding new calls — and that could go 85 unnoticed even if you have a linter prohibiting that (becase of the reason stated above), and even 86 pass CI. _I also observed that being done in popular packages._ 87 88 Some examples: 89 * [webdriverio](https://github.com/webdriverio/webdriverio/commit/05cbd3167c12e4930f09ef7cf93b127ba4effae4#diff-124380949022817b90b622871837d56cR31) 90 (a module with 548 759 downloads/month), 91 * [websocket-stream](https://github.com/maxogden/websocket-stream/commit/c9312bd24d08271687d76da0fe3c83493871cf61) 92 (218 288 d/m, fix in [maxogden/websocket-stream#142](https://github.com/maxogden/websocket-stream/pull/142)), 93 * [node-serialport](https://github.com/node-serialport/node-serialport/commit/e8d9d2b16c664224920ce1c895199b1ce2def48c) 94 (113 138 d/m, fix in [node-serialport/node-serialport#1510](https://github.com/node-serialport/node-serialport/pull/1510)), 95 * [karma](https://github.com/karma-runner/karma/commit/3d94b8cf18c695104ca195334dc75ff054c74eec) 96 (3 973 193 d/m, fix in [karma-runner/karma#2947](https://github.com/karma-runner/karma/pull/2947)), 97 * [spdy-transport](https://github.com/spdy-http2/spdy-transport/commit/5375ac33f4a62a4f65bcfc2827447d42a5dbe8b1) 98 (5 970 727 d/m, fix in [spdy-http2/spdy-transport#53](https://github.com/spdy-http2/spdy-transport/pull/53)). 99 * And there are a lot more over the ecosystem. 100 101 I filed a PR at 102 [mysticatea/eslint-plugin-node#110](https://github.com/mysticatea/eslint-plugin-node/pull/110) to 103 partially fix that (for cases when that lint rule is used), but it is a semver-major change for 104 linter rules and presets, so it would take significant time for that to reach actual setups. 105 _It also hasn't been released yet (2018-03-20)._ 106 107 Also, `safer-buffer` discourages the usage of `.allocUnsafe()`, which is often done by a mistake. 108 It still supports it with an explicit concern barier, by placing it under 109 `require('safer-buffer/dangereous')`. 110 111 ## But isn't throwing bad? 112 113 Not really. It's an error that could be noticed and fixed early, instead of causing havoc later like 114 unguarded `new Buffer()` calls that end up receiving user input can do. 115 116 This package affects only the files where `var Buffer = require('safer-buffer').Buffer` was done, so 117 it is really simple to keep track of things and make sure that you don't mix old API usage with that. 118 Also, CI should hint anything that you might have missed. 119 120 New commits, if tested, won't land new usage of unsafe Buffer API this way. 121 _Node.js 10.x also deals with that by printing a runtime depecation warning._ 122 123 ### Would it affect third-party modules? 124 125 No, unless you explicitly do an awful thing like monkey-patching or overriding the built-in `Buffer`. 126 Don't do that. 127 128 ### But I don't want throwing… 129 130 That is also fine! 131 132 Also, it could be better in some cases when you don't comprehensive enough test coverage. 133 134 In that case — just don't override `Buffer` and use 135 `var SaferBuffer = require('safer-buffer').Buffer` instead. 136 137 That way, everything using `Buffer` natively would still work, but there would be two drawbacks: 138 139 * `Buffer.from`/`Buffer.alloc` won't be polyfilled — use `SaferBuffer.from` and 140 `SaferBuffer.alloc` instead. 141 * You are still open to accidentally using the insecure deprecated API — use a linter to catch that. 142 143 Note that using a linter to catch accidential `Buffer` constructor usage in this case is strongly 144 recommended. `Buffer` is not overriden in this usecase, so linters won't get confused. 145 146 ## «Without footguns»? 147 148 Well, it is still possible to do _some_ things with `Buffer` API, e.g. accessing `.buffer` property 149 on older versions and duping things from there. You shouldn't do that in your code, probabably. 150 151 The intention is to remove the most significant footguns that affect lots of packages in the 152 ecosystem, and to do it in the proper way. 153 154 Also, this package doesn't protect against security issues affecting some Node.js versions, so for 155 usage in your own production code, it is still recommended to update to a Node.js version 156 [supported by upstream](https://github.com/nodejs/release#release-schedule).