Comments for dpunk!

Comment on AthCon 2010 by Thiseas

Thiseas — Sun, 06 Jun 2010 17:58:51 +0000

+100 Mr Dpunk…!
just +100!!
Thank you too for your real nice and advance presentation.

Comment on 10 things you should be careful about when auditing sources by c00kiemon5ter

c00kiemon5ter — Sat, 01 May 2010 14:16:28 +0000

Case 5: opne() and AUCERT
The link maybe this : Secure Unix Programming Checklist
http://auscert.org.au/render.html?it=1975

on open() among others :
[....]
23. NEVER use system() or popen() calls. execlp and execvp are also
suspect.
24. If you are expecting to create a new file with the open
call, then use the O_EXCL|O_CREAT flags to cause the
routine to fail if the file exists. If you expect the
file to be there, be sure not to include the O_CREAT flag
so that the routine will fail.
[....]
To open a file, which should already exist:

– lstat() the path, check that lstat succeeded
– check that it’s acceptable (eg, not a symlink)
– open() (without O_CREAT), check that the open succeeded
– fstat() the fd returned by open
– if the lstat and fstat st_ino and st_dev fields match,
accept.

To create a new file, which doesn’t already exist:

– lstat() the path, check that you got ENOENT
– open(…,…|O_CREAT|O_EXCL,…), check that it succeeded

If you’re really paranoid, then:

– fstat() the fd returned by open
– lstat() the path again, check that (a) it exists and (b)
isn’t a symlink
– check that the fstat and the last lstat returned matching
st_dev and st_ino fields

NOTE: that the latter depends on the O_CREAT|O_EXCL semantics
of not following a trailing symlink.
[....]

hope this helps a bit,
nice blog ;-]

Comment on Python in noexec-land by some guy

some guy — Thu, 18 Mar 2010 12:21:35 +0000

LOL, this is almost a year old but, as a loyal Ruby fanboi, I need to chime in:
Ruby has FFI as well (actually it has quite a few, depending on your implementation) BUT there is little if any documentation. Ctypes just has ALL the docs you can use so python wins :-)

I cannot comment on Perl, I ain’t no perl guy :-)

Cheers and keep up the good work!

Comment on In Berlin everything’s about *wurst\x00 by guerrilla

guerrilla — Mon, 04 Jan 2010 09:23:38 +0000

Instead of looking into Dragon Book’s version of Syntax Directed Translation, I suggest that you should look at attribute grammars because the semantics are completely defined (unlike SDD) while providing exactly the same facility (if not more). I think you could learn a lot from the mathematical models. Specifically “extended attribute grammars” which provide a semantics and syntax similar to BNF.
I’ve been thinking about writing a post introducing formal attribute grammars but haven’t got around to it yet. We’ll see.

Comment on In Berlin everything’s about *wurst\x00 by xorl

xorl — Sun, 03 Jan 2010 04:38:50 +0000

welcome back sir

Comment on 10 things you should be careful about when auditing sources by SolidSNK

SolidSNK — Fri, 04 Dec 2009 15:57:00 +0000

Impostor!

Comment on 10 things you should be careful about when auditing sources by decepticonpunk

decepticonpunk — Sun, 29 Nov 2009 14:37:15 +0000

What are you talking about? :-P

Comment on 10 things you should be careful about when auditing sources by SolidSNK

SolidSNK — Sat, 28 Nov 2009 11:52:37 +0000

R.I.P. huku. That swine flu proved nasty.

Goodnight sweet prince

Comment on 10 things you should be careful about when auditing sources by redbrain

redbrain — Tue, 10 Nov 2009 23:28:00 +0000

Yep good job its the little things when your learning back in the day you had to learn by making all the mistakes hehe, i made some many stupid mistakes when i think about it haha.

Another suggestion would be

#define xfree( ptr ) \
assert( ptr != NULL ); \
free( ptr ); \
ptr= NULL;

to make sure your ptr is nullified properly! :)

Comment on 10 things you should be careful about when auditing sources by argp

argp — Fri, 06 Nov 2009 12:26:07 +0000

Very nice and well-written post. One thing I would add to the list is the wrong use of the sizeof unary operator (which you indirectly referred to in case 3 about strncpy()). For example

buffer[sizeof(buffer)] = NULL;

and

if(strlen(str_input) > sizeof(buffer))

are very common mistakes.