Add more Psalm flows for string functions

[LukasReschke]

This adds string functions from https://www.php.net/manual/en/ref.strings.php

This commit adds the flows for functions from "addcslashes" to "sprintf".

More are to follow in later commits, if that is deemed useful :)

Ref #3636

[muglug]

This is great, thanks!

[thbley]

Using the new release 4.2, I get "Detected tainted header" using https://psalm.dev/r/21c22b8fb6

What is the best way to handle this?

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/21c22b8fb6

<?php // --taint-analysis

$test = (string) ($_POST['test'] ?? '');

header('Content-Disposition: attachment; filename="' . addslashes($test) . '"');

Psalm output (using commit ccf6e28):

ERROR: TaintedHeader - 5:8 - Detected tainted header

[LukasReschke]

@thomasbley You could create a new function that is marked as sanitizer.

https://psalm.dev/r/5fb5ba744f

<?php // --taint-analysis

$test = (string) ($_POST['test'] ?? '');


/**
 * @psalm-taint-escape header
 */
function addFileNameToContentDisposition(string $fileName) : string {
    return addslashes($fileName);
}

header('Content-Disposition: attachment; filename="' . addFileNameToContentDisposition($test) . '"');

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/5fb5ba744f

<?php // --taint-analysis

$test = (string) ($_POST['test'] ?? '');


/**
 * @psalm-taint-escape header
 */
function addFileNameToContentDisposition(string $fileName) : string {
    return addslashes($fileName);
}

header('Content-Disposition: attachment; filename="' . addFileNameToContentDisposition($test) . '"');

Psalm output (using commit ccf6e28):

No issues!