url: fix port overflow checking

[rmisev]

This patch adds (port > 0xffff) check after each digit in the loop and prevents integer overflow.

In the current implementation a result can be incorrect if an integer overflow occurs. For example:

const URL = require('url').URL;
const url = new URL("http://example.com:4294967377/");
console.log(url.port);
// actual: 81
// expected: failure (TypeError)

Refs: web-platform-tests/wpt#7602

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• commit message follows commit guidelines

Affected core subsystem(s)

url

[mscdex]

Maybe only bother checking if the buffer length is > 4? I think that will avoid having to check for most common ports.

[rmisev]

@mscdex I think your proposal complicates code a bit, and a gain is minimal - only three comparisons less for 4-digit port :

    int port = 0;
    if (buffer.size() <= 4) {
      // port overflow will not occur
      for (size_t i = 0; i < buffer.size(); i++)
        port = port * 10 + buffer[i] - '0';
    } else {
      for (size_t i = 0; i < buffer.size(); i++) {
        port = port * 10 + buffer[i] - '0';
        // prevent integer overflow
        if (port > 0xffff) break;
      }
    }

What do you think?

[addaleax]

I think it might even get a little clearer now if you make this unsigned

[rmisev]

Yes, makes sense. Changed.

[TimothyGu]

nit: the port > 0xffff could be moved into the for-loop head

[rmisev]

Seems reasonable, moved.

[joyeecheung]

CI: https://ci.nodejs.org/job/node-test-pull-request/10484/

[addaleax]

There are CI failures like this:

not ok 1615 parallel/test-whatwg-url-parsing
  ---
  duration_ms: 0.213
  severity: fail
  stack: |-
    Mismatched <anonymous> function calls. Expected exactly 110, actual 113.
        at Object.exports.mustCall (/home/iojs/build/workspace/node-test-commit-linux/nodes/ubuntu1610-x64/test/common/index.js:485:10)
        at Object.expectsError (/home/iojs/build/workspace/node-test-commit-linux/nodes/ubuntu1610-x64/test/common/index.js:710:27)
        at Object.<anonymous> (/home/iojs/build/workspace/node-test-commit-linux/nodes/ubuntu1610-x64/test/parallel/test-whatwg-url-parsing.js:28:30)
        at Module._compile (module.js:600:30)
        at Object.Module._extensions..js (module.js:611:10)
        at Module.load (module.js:521:32)
        at tryModuleLoad (module.js:484:12)
        at Function.Module._load (module.js:476:3)
        at Function.Module.runMain (module.js:641:10)

I guess that’s just a mismatched test counter that needs to be updated or something like that?

[joyeecheung]

I think the counter here is just failureTests.length, there is no need to hard-code this

[rmisev]

agree, done.

[joyeecheung]

CI: https://ci.nodejs.org/job/node-test-pull-request/10568/

[TimothyGu]

Landed in 92146e0.