Nmap Development mailing list archives
Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans)
From: doug () hcsw org
Date: Mon, 6 Apr 2009 06:38:17 +0000
On Fri, Apr 03, 2009 at 08:53:26PM +0000 or thereabouts, Brandon Enright wrote:
I think we can make the following substitution on all s modifier match lines (untested): s/[.][*]([\]r[\]n|[\]n)*?[.][*]/.*/gI agree but I'd suggest a few modifications. First) we need to make sure your first [.] isn't preceded by a \ (easy with negative look-behind).
Aha! Good one. That's very true.
Second) in most cases the content trailing the .* is still in the header and not in the body. Lazy quantification with .*? should be generally faster because it won't consume the whole string and then slowly back off. I'd propose changing to .*? in the case that the trailing content is still in the header and .* when the trailing content is in the body.
I'm not that concerned with this especially if the strings are unique enough but there's no harm here either.
If you're okay with me going through by hand and replacing .*\r?\n.* with .* or .*? I'll get started right away. There are about 50 matches that need work.
Sounds great, thank you. If you like I will take a quick look at the patch but I'm sure I don't need to because you will do it fine. Best, Doug
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Current thread:
- [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) Brandon Enright (Apr 02)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) doug (Apr 02)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) Brandon Enright (Apr 03)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) doug (Apr 05)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) Brandon Enright (Apr 07)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) Brandon Enright (Apr 03)
- Re: [RFC] PCRE MATCHLIMIT and the use of greedy quantifiers (-sV scans) doug (Apr 02)