PHP 4.0 Bug #7749 Updated: addslashes wrong thing to do

ID: 7749 Updated by: andrei Reported By: james+phpbug@squish.net Status: Assigned Bug Type: PCRE related Assigned To: andrei Comments: Previous Comments: --------------------------------------------------------------------------- [2000-11-10 11:53:43] james+phpbug@squish.net Three bugs. preg_replace: $text = preg_replace('/(foo(bar)?) is a good word/', 'wibble', $text); Simple enough. How about: $text = preg_replace(/'(foo(bar)?) is a good word/e', '(length('2')>0)?"wibble":"wobble"', $text); The first thing to note here is that the idea of substituting into the replacement string like this was a very bad idea, I would encourage you to phase this out in favour of $<num> replacement. The two obvious things that PHP could get wrong with this form of substitution, PHP gets wrong :-) Firstly - when 2 does not exist because there was no match, you should should get '', infact with PHP you get ^B, it seems you're simply looking for <nums> that created matches rather than all <nums. Secondly - as a security-aware person, I immediate recognise the problems that '1' could cause. A quick look at the code reveals that (thankfully) some effort is being made to quote the inserted string (undocumentedly). However, the code in PHP uses addslashes() which was designed for database use and not internal PHP single-quote escaping. PHP's single-quotes only look for ' and \ and therefore the escaping of " to " and NULL to