Wireshark mailing list archives

Re: checkapi


From: Graham Bloice <graham.bloice () trihedral com>
Date: Fri, 22 Apr 2016 16:31:42 +0100

On 22 April 2016 at 15:48, Evan Huus <eapache () gmail com> wrote:

On Fri, Apr 22, 2016 at 10:24 AM, Jeff Morriss
<jeff.morriss.ws () gmail com> wrote:


On Fri, Apr 22, 2016 at 3:28 AM, Graham Bloice <
graham.bloice () trihedral com>
wrote:

Just thinking for this for about 30 secs, is there another way?
checkAPIs
seems to be a very rudimentary (not meant in any derogatory way just
because
it's written in Perl :_)) static code analyser.  Is there any way an
actual
code analyser could be used with a configuration file listing the banned
API's etc.?  I guess one issue with that approach is that all the static
analysers I've used are quite slow, although that's maybe because I have
them turned up to 11.


There are; someone (Evan?) suggested a couple of options a few years ago
but
I guess no one had enough interest to do anything about it.  But either
my
memory is wrong or my Google-fu isn't working well today because all I'm
finding is a suggestion from Sebastien way back in 2008 (I really
thought it
was discussed more recently than that--and with more suggestions):

https://www.wireshark.org/lists/wireshark-dev/200805/msg00128.html

I think I remember talking about http://cppcheck.sourceforge.net/ -
IIRC it lets you define custom rules either as regexes or as more
complex scripts on the C/C++ AST, though I haven't looked at it in a
while.


Interestingly I just ran cppcheck on Wireshark this week which turned up
some interesting stuff as cppcheck has "knowledge" of frameworks such as
gtk and qt (and windows) and thus is aware of when allocations have been
made by library calls and should be cleaned up, e.g. line 119 of
packet-pmproxy.c:

    return g_strcmp0(pmproxy_exchange_string, g_strdup_printf("pmproxy-%s
1\n", type)) == 0;

The g_strdup_printf() allocates a string which has to be freed with
g_free().

Of course I doubt such tools could fully replace checkAPIs: it has a lot
of
custom stuff in there like ensuring various arrays are NULL terminated
and
that hf fields are appropriate (writing the regex to match all the hf
array
entries was all sorts of challenging fun :-)).

This may be somewhere a little bit of AST might go a long way, but it
would certainly be a lot of work to migrate everything over.


This was the approach I was thinking, once you have an AST and a symbol
table, lots of things are possible.


(You really should just come on over to the world of Perl; eventually
you'll
wonder how you ever got along without it! ;-))



Tried that once, still feel unclean.  Only php is worse, mainly due to the
huge amount of insecure php web apps I have run into.

-- 
Graham Bloice
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