[cfe-users] Running 'scan-build' in SRD's test cases (NIST)

Edoardo P. ed0.88.prez at gmail.com
Thu Feb 20 06:26:10 PST 2014


Hi Lucas:


> I am doing today a script to run all test case in Juliet with Clang and
> generate a report (CSV file), when a finished this i will send you the
> results.


Please do.


> But a run manually and clang can find only 54 weaknesses in a
> total of 1476 files (into testcases/CWE369_Divide_by_zero, including s01
> and s02 directories).
>
>
I can confirm that. In IRC I discussed with some llvm devs about the need
to report the float division by zero (Standard C/C++ says it's undefined
behavior, but Annex F implicitly allows it, thanks to IEEE 754). I have an
idea: add a new static analyzer option which allows or disallows optional
features, including the optional Annexes. That would help a lot imho.

Cheers,
Edward-san


> On Tue, 2014-02-18 at 16:19 +0100, Edoardo P. wrote:
> > Hi, Lucas, Jordan:
> >
> >
> > About the division by zero checking, I run this:
> >
> >
> > scan-build --use-analyzer /usr/bin/clang -o buildres/ clang -c -I
> > testcasesupport -DOMITGOOD
> >
> testcases/CWE369_Divide_by_Zero/s02/CWE369_Divide_by_Zero__int_zero_divide_01.c
> -o /dev/null
> >
> >
> > and I get the warnng:
> >
> >
> testcases/CWE369_Divide_by_Zero/s02/CWE369_Divide_by_Zero__int_zero_divide_01.c:30:22:
> warning: Division by zero
> >     printIntLine(100 / data);
> >                  ~~~~^~~~~~
> >
> >
> > So, Lucas, which file was failing for you?
> >
> >
> > Regarding the experience, here it is what I gathered till now:
> >
> > I created a very huge file_list.txt, containing the source files to
> > compile (I used 'find -name *.c*' in the juliet directory), then
> > filtered away the 'main\.c', 'main_linux\.c' and 'testcasesupport'
> > files (grep -v), which have nothing to check, then I sorted the list
> > by CWE number (I had to do manual sorting because I couldn't manage to
> > sort, for example, CWE15_* and CWE114_* correctly).
> >
> > Since I can't check for win32-only tests (I'm using linux), I filtered
> > them via 'grep -v w32' and 'grep -v wchar_t' (some tests require a
> > 'fopen'-like function with wchar_t string, which seems to be exclusive
> > to win32).
> >
> >
> > Regarding the per-translation-unit analysis, some files are, indeed,
> > separated sources for a program, so I didn't hesitate to filter them
> > with these patterns, according to the manual: "[abcdeBG]\.c" and
> > "good1" (last was associated with a 'bad' file, which was already
> > filtered).
> >
> >
> > With this file_lists.txt, I run the static analyzer only for the false
> > positives, with this command:
> >
> > < file_list.txt xargs -n 1 scan-build --use-analyzer /usr/bin/clang
> > -disable-checker deadcode.DeadStores -o buildres/ clang -c -I
> > testcasesupport -DOMITBAD -o /dev/null > /dev/null 2> warns.txt
> >
> >
> > so, it checks all the files in the file list, saves the results in
> > buildres and reports the warnings in warns.txt file, ignoring the
> > DeadStores warns because they're reported a lot often.
> >
> >
> > Well, there are tons of false positives, caused by the flow variants
> > which involve global and static variables, shadow variables usage,
> > etc.
> >
> >
> > To the devs, I'd like to know which CWE are you interested, from the
> > list I attached on that email:
> > http://lists.cs.uiuc.edu/pipermail/cfe-dev/2014-February/035113.html .
> >
> >
> > About the results, if I have more time, I'll post some of them.
> >
> >
> >
> > 2014-02-18 2:05 GMT+01:00 Lucas Kanashiro
> > <kanashiro.duarte at gmail.com>:
> >         Thanks Jordan!
> >
> >         Could you leave me updated on the matter? I am so interested
> >         in this,
> >         and if it is necessary and possible i want to help to solve
> >         the
> >         potential issue.
> >
> >         Edward, can you tell us your experience with Clang and Juliet
> >         Test
> >         Suite?
> >
> >
> >         On Mon, 2014-02-17 at 09:43 -0800, Jordan Rose wrote:
> >         > Hi, Lucas. The analyzer currently runs a
> >         per-translation-unit analysis, so it misses some bugs that
> >         whole-program analysis may be able to catch. I'm guessing
> >         that's the reason it's unable to catch this particular issue.
> >         >
> >         > In general, the analyzer is set for reasonably fast
> >         turnaround (depending on the size of the project, of course),
> >         so it also might not do a fully precise interprocedural
> >         analysis if the state space gets too big. I'd have to see the
> >         particular test case to tell what's going on here.
> >         >
> >         > I did see that Edward (CC'd) wanted to try bringing in the
> >         Juliet Test Suite for the analyzer, but neither I nor Ted (the
> >         lead on the analyzer) have gotten the chance to sit down and
> >         look at what this would actually entail. It's possible he's
> >         encountered similar issues, however.
> >         >
> >         > Jordan
> >         >
> >         >
> >         > On Feb 15, 2014, at 5:58 , Lucas Kanashiro
> >         <kanashiro.duarte at gmail.com> wrote:
> >         >
> >         > > I am trying to running 'scan-build' in Juliet suite
> >         testcase v1.2 (NIST
> >         > > indication) to catch some bugs of 'Division by zero' (CWE
> >         369) and I
> >         > > can't do it, the scan-build can't show me the existing
> >         bugs. Did someone
> >         > > try to do it yet?
> >         > >
> >         > > I have a doubt that scan-build can identify a bug of
> >         division by zero in
> >         > > this case (when parameter denominator is zero):
> >         > >
> >         > > int divide (int denominator) {
> >         > >     return 10/denominator;
> >         > > }
> >         > >
> >         > > Can someone help me? Is this a deficiency of scan-build?
> >         Can scan-build
> >         > > identify the bugs in Juliet suite?
> >         > >
> >         > > Thanks in advance!
> >         > >
> >         > > --
> >         > > Lucas Kanashiro Duarte
> >         > > Engenharia de Software - FGA/UnB
> >         > > kanashiro.duarte at gmail.com
> >         > >
> >         > > _______________________________________________
> >         > > cfe-users mailing list
> >         > > cfe-users at cs.uiuc.edu
> >         > > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-users
> >         >
> >
> >         --
> >         Lucas Kanashiro Duarte
> >         Engenharia de Software - FGA/UnB
> >         kanashiro.duarte at gmail.com
> >
> >
> >
> >
> >
> > --
> > Mathematics is the language with which God has written the universe.
> > (Galilei)
>
> --
> Lucas Kanashiro Duarte
> Engenharia de Software - FGA/UnB
> kanashiro.duarte at gmail.com
>
>


-- 
Mathematics is the language with which God has written the universe.
(Galilei)
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