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US DHS Testing FOSS Security
Stony Stevenson alerts us to a US Department of Homeland Security program in which subcontractors have been examining FOSS source code for security vulnerabilities. InformationWeek.com takes a glass-half-empty approach to reporting the story, saying that for FOSS code on average 1 line in 1000 contains a security bug. From the article: 'A total of 7,826 open source project defects have been fixed through the Homeland Security review, or one every two hours since it was launched in 2006 ...' ZDNet Australia prefers to emphasize those FOSS projects that fixed every reported bug, thus achieving a clean bill of health according to DHS. These include PHP, Perl, Python, Postfix, and Samba.
Now if they would do the same to Microsoft. Oh yeah...
Do they mean fixed or fixed?
You can't ever say that proprietary software is secure, because there's no way to prove it. With Open Source, you can come a lot closer to proving that it is secure, because you can employ every security test that exists.
The fact that a coverity scanner bug is reported doesn't mean it's an exploitable security flaw.
Bruce
Bruce Perens.
Uh.. from the article, the software is called "Prevent Software Quality System"... Wow, I can't think of a bigger misnomer for something that should help improve software quality. I sure don't want to prevent software quality in my own products.
Although I understand what you're trying to say, it does seem a little irrelevant.
I'm a software security engineer. I can look at source code and tell you if it has some bugs in it that I would consider relevant to security. If I can't find any, I might tell you that it is more secure than if I could... but that's doesn't mean it is secure. I'll never tell you it is secure, because testing simply can't give you that. I can do this on proprietary software or I can do this on Open Source software.. the only difference is that, with the Open Source software, I don't need permission from someone to do the testing and other people don't need permission to check my work.
Does this mean that more people will check the Open Source software for security flaws? Not necessarily. It completely depends on whether or not someone has an interest in the security of that particular bit of software. Even assuming a similar level of interest in the security of comparable proprietary and Open Source software, there's no guarantee that those who have an interest in testing the Open Source software for security flaws will report back the findings. They may simply decide that the Open Source software is too insecure for their use and go with the proprietary solution - assuming they can have it similarly tested by a trusted third party.
All in all, the assumption that Open Source software is more secure than proprietary software is most likely true, but there's no hard data.. because the stats on the insecurity of proprietary software are guarded secrets - and that's probably the best reason to assume that proprietary software is less secure.
How we know is more important than what we know.
How could he possibly know that? He said already that he stopped reading after 'the PHP'.
Crumb's Corollary: Never bring a knife to a bun fight.
This seems like a genuinely useful activity for DHS, certainly more valuable than x-raying my shoes and confiscating my saline solution.
What I'm listening to now on Pandora...
Indeed. FTFA:
One can only speculate about the, er, source of their discomfort.... 8^)
1 per 1000 lines is even more impressive as an average across all 180 FOSS applications tested. Most impressive of all are the highlights:
Even some of those with more bugs have at least responded well:
And my favourite 'backslider' of all, OpenVPN, has yet to fix 100% of the bugs found during this exercise. Of course, that's only 1 bug in over 69,000 lines of code....
These results should be viewed as excellent, by and large. This doesn't mean all this software is bug-free, just that there aren't a lot of easily preventable bugs in the code base. Most encouraging, though, is how fast they got addressed and fixed by the healthier FOSS projects.
Crumb's Corollary: Never bring a knife to a bun fight.
From TFA:
The popular MySQL open source database was not included in the scans for reasons that were not immediately evident.
Any suggestions as to why MySQL has no results? I'm stumped and wondering why one whole corner of a LAMP foundation was left unchecked.
I submit that people who are only looking for security flaws don't have a motivation to develop a deep understanding of the software. People who are out to modify the software do. And thus there are not just more eyes, but better eyes with Free Software.
There is a class of mathematically provable software languages, and you might be able to say with surety that programs in them are secure. For the languages we usually use, you can only say that you have tested them in the ways you know of. And only a person with access to the source can say that. If you want an independent asessment, Open Source software won't stop one from happening, and won't hinder what can be said with NDAs. That's why I think it's more secure.
Bruce
Bruce Perens.
Not only did the article say much like its commercial counterpart, but most of the numbers it shows are actually good for open source software.
For instance, most of the projects discussed had less than 1 bug for 1000 lines of code. For instance, the Linux kernel had .127 bugs per 1000 lines, and that on over 3 million lines of code.
Also, the article talks about key projects, such as the glibc (which is basically used by everything on a Linux system) that already fixed all the issues.
Even something huge and complex as Firefox has already fixed half of the issues, and is showing progress on the rest of them (by the fact that some were already verified).
Overall, I didn't get the half glass empty tone that the summary is implying. And what I found strange is that even the comments on the site itself, and many of them on /. itself, are also taking the pessimistic view.
I thought that this news are great for open source software. Shows that it has less security issues than average, that the issues are fixed quickly, and still that some programs are certified by a company for use in security related departments such as the DHS. What could be better than that?
First off, prevent is not strictly a security flaw static-analysis checker. It is a static-analysis checker that checks for all sorts of defects. Some of which are directly related to security. Second, I have used prevent extensively over the past year and have found it to be an invaluable tool. It has a pretty low false positive rate and fixing the defects it finds means your code is better. On the code I work on, I find that we have a much lower defect count. But we also have pretty mature code and we really do attempt to make it as bullet proof as possible. But we still have defects.
My experience is with the C/C++ version of tool. We have also been evaluating the java version of the tool and it is good. But some of the free alternatives like findbugs are still better. I would use findbugs w/ prevent for java if I wanted good coverage.
There are industry estimates that say average code in production contains 2 bugs per thousand lines of code. Some say that number is much higher. How many lines do you think are in Vista?
Yes, OSS has bugs. Everything from compilers to content management systems, surely. So do proprietary programs.
The more qualified eyes you get on a bug, the better chance you have of finding and fixing it. You can do that by having a big staff that pores over code again and again. You can do it by having lots of outside help, like in the case of popular OSS projects. One thing that helps is to have a fresh set of eyes look over something, which is much easier in OSS that in closed-source applications.
BusinessWeek had an article from a guy at Coverity back in 2006 about this. In that article, Ben Chelf said that 4 of the top 15 programs on the quality scale measured by defects per thousand lines of code were OSS. He said that on average, the major-project OSS software they tested was indeed higher quality software than average. He said, though, that the absolute highest quality code was the cream-of-the-crop proprietary, closed source code from places that make things like fly-by-wire systems. Well, yeah. I'd want my airliner's fly-by-wire system completely bug-free, too.
Commercial software tends to harbor anywhere from 1 to 7 bugs per 1000 lines of code according to the National Cybersecurity Partnership's Working Group on the Software Lifecycle. Voluntary testing by Coverity requested (and probably paid for) by MySQL AB revealed that project to have all of 97 flaws, one of which could be a serious security issue. All 97 were to be fixed for the next release.
A similar study (same link) found 985 bugs in over 5,700,000 lines in the Linux kernel, or fewer than one bug per 10,000 lines of code. TFA has data on a newer version of the kernel -- 0.127 bugs per TLOC.
In Apache, 22 bugs total, 0.14 per TLOC, and three fixed so far.
PostgreSQL had 0.041 per TLOC, and have so far fixed 53 of the 90 bugs.
The glibc team fixed 83 of 83 bugs found.
OpenVPN had found one security-related bug in over 69,000 lines of code. As of later yesterday, it's officially security bug free according to the same testing people.
The list of officially security-bug free software includes Amanda, NTP, OpenPAM, OpenVPN, Overdose, Perl, PHP, Postfix, Python, Samba, and TCL.
So with Linux (0.127), glibc (0.000), Apache (0.140), PostgresSQL (0.041), Perl (0.024), PHP (0.000), and Python (0.000) powering a web server (numbers according to Coverity), you have 0.0474 defects per thousand lines of code across the server. I'd say that's pretty good.
So with Linux (0.127), glibc (0.000), Apache (0.140), PostgresSQL (0.041), Perl (0.024), PHP (0.000), and Python (0.000) powering a web server (numbers according to Coverity), you have 0.0474 defects per thousand lines of code across the server. I'd say that's pretty good.
I'd say your statistic is wrong. You need to multiply each average by the number of kloc per project (being careful to count those for the project version for which the averages were given), and then divide by the total kloc across all projects.
Just has to do with coding methodology. strcpy is insecure, strncpy is more so. strncpy(src, dst, sizeof(dst)) is more secure than strncpy(src, dst, size_of_dst). Those are easy to fix security bugs. Other security bugs are harder to find as you have to trace the myriad of states the app can be in during mem writes.
/* We'll just fit as much of the translated error as possible into this buffer */
strcpy is NOT insecure. It can be used insecurely.
But congratulations, you've just turned what could have been a borderline ok strcpy(src, dst) (ought to have been criticized at code review as the names of the variables are confusing) bit of code into (probably) a crash and definitely a buffer overrun if sizeof dst is larger than sizeof src.
I have lost count of the number of bugs I've had to fix after someone changed a perfectly good strcpy into strncpy. A common mistake is:
strcpy(dst, src);
becomes
strncpy(dst, src, sizeof dst);
and then you get a bug because only the first four characters of src appear in dst followed by garbage.
Of course, then it gets changed to
strncpy(dst, src, strlen(src));
because the original programmer did know what they were doing and the buffer was big enough.
Eventually we get to the brilliant:
strncpy(dst, src, strlen(src)+1);
Fantastic! What an improvement! And yes, it really does happen in what was once good production code because some idiot has heard that "strcpy is insecure".
Another one I've seen is:
dst = malloc(1000000);
strcpy(dst, "MESSAGE");
gets changed to
dst = malloc(1000000);
strncpy(dst, "MESSAGE", 1000000);
Yup, instead of writing 8 bytes, we'll write one million bytes because strcpy is insecure, but we won't fix the missing check for NULL. (there's a fairly good argument for not checking the return from malloc in much production code - if malloc actually fails then you're already so far up shit creek without a paddle that it's probably impossible to recover gracefully anyway. Obviously different considerations will apply if you're controlling a nuclear power plant than if you're writing a game)
strncpy is NOT a replacement for strcpy with a length parameter. Unfortunately strncpy has a very bad name, it should be called something like meminit_from_str() as strncpy ALWAYS writes n bytes and doesn't always write a null terminator. (I've also had to fix bugs where someone has replaced a correct use of strncpy with a version that guarantees to write the null)
strncat is a possibly safer replacement for strcat. However, the length parameter is so tricky to get right that I've seen cases where someone originally wrote strcat safely, that got changed to strncat "because it's safer" and then a bit later another change was made that caused a crash because the original change to strncat got the length parameter wrong.
extern char error_msg[][40];
char error[64];
strcpy(error, "ERROR");
strcat(error, error_msg[e]);
becomes
strncpy(error, "ERROR:", sizeof error);
strncat(error, error_msg[e], sizeof error - 6);
becomes
strncpy(error, get_translation("ERROR:", lang), sizeof error);
strncat(error, translated_error_msg(e, lang), sizeof error - strlen(error));
of course, even more common is to miss the -6 or strlen(error) completely than to remember the extra -1 that is required on the length parameter.
(The man pages are IMO, confusing for strncat as they usually say something along the lines of "appends at most n characters")
Tim.
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t," and there was light.