vimeo/psalm

Taint analysis: support conditional escaping for class methods

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#5,053 opened on Jan 19, 2021

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 (4 comments) (1 reaction) (0 assignees)PHP (668 forks)batch import
Help wantedbugtaint analysis

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Description

Follow up for #4661. Works for plain functions and static methods (really great :+1:, thanks for that). Could that be implemented for non-static methods too? May be a little tricky without taint-specialize/pure?

class DB {
	/**
	 * @psalm-taint-specialize
	 * @psalm-taint-escape ($type is "expression" ? null : "sql") $val
	 */
	public function quote(string $val, string $type): string {
		return $val;
	}
}

function x(PDO $p, DB $db): void {
	$a = (string)$_REQUEST['a'];

	$p->exec($db->quote($a, '')); // false positive
	$p->exec($db->quote($a, 'expression'));
}

https://psalm.dev/r/06814dc3d3

Contributor guide

Research direction
Examine the implementation in PR #4661 and adapt it for non static methods, considering the need for taint specialize annotation.
Tech stack
php
Domain
security
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
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Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PHP
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40