Re: libxt_string: fix undefined behavior/incorrect patlen calculation

[John Haxby <john.haxby@oracle.com>]

Jan Engelhardt wrote:
> On Sunday 2009-03-01 23:37, pud wrote:
>   
>> (sorry, msg-id lost)
>>
>>     
>>> commit 19b0cd770d1e042c85bf0b278261a61d4cea8193
>>> Author: Jan Engelhardt <jeng...@medozas.de>
>>> Date: Thu Feb 12 01:18:35 2009 +0100
>>>       
>> ...
>>     
>>> - stringinfo->patlen=strlen((char *)&stringinfo->pattern);
>>> + stringinfo->patlen = strnlen((char *)&stringinfo->pattern,
>>> +                           sizeof(stringinfo->patlen));
>>>       
>> sorry, this doesn't work here, did you mean
>> sizeof(stringinfo->pattern)?
>>     
>
> What do you mean "doesnot work"?
>   

It looks very weird to me as well.   I may well be confused, but

    stringinfo->patlen = strnlen((char *)&stringinfo->pattern, 
sizeof(stringinfo->patlen))

looks like something roughly equivalent to this:

    char pattern[256];
    int patlen;
    patlen = strlen(pattern, 4);

The "4" is sizeof(int) rather than the size of "pattern"

jch