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Software Code Quality Of Apache Analyzed
fruey writes "Following Reasoning's February analysis of the Linux TCP/IP stack (putting it ahead of many commercial implementations for it's low error density), they recently pitted Apache 2.1 source code against commercial web server offerings, although they don't say which. Apparently, Apache is close, but no cigar..."
Why don't they fix them? It seems almost paradoxical, if you find .53 errors per thousands lines of code and fix them, then you'll have 0 errors. But since we can only fix errors we can detect, we only detect errors we can fix. Ok, it's too early on a Monday morning...
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2.1 is'nt even out yet! the latest is 2.0.46!
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Just because Open-Source coders can't spell when they insert comments doesn't mean that they can't write good code!
But here's the kicker: the vast majority runs Apache on either BSD or Linux. All of this code, from the kernel to the library that tells Apache how to use PHP, is open source. Every hacker on the planet has full access to the code - which means that they can review it and find vulnerabilities in it. Not many people have access to Windows or IIS code. So why does IIS and Windows come out as far less secure, and is exploited so much more?
I think the answer lies in the severity of the code defects, and the architecture and design of the operating system that powers the web server. And yes, I know that Apache can run on Windows.
Reasoning found 31 software defects in 58,944 lines of source code of the Apache http server V2.1 code.
so what are the calling a defect?
Wouldn't that be unstable? I thought the latest was 2.0.46 or something.. If I'm not mistaken, it would be a bit like saying "Freebsd 4.8 has less bugs than Linux 2.5!"
So basically they offer a service like lclint only many times more advanced ? What is to say they haven't missed anything?
This is probably a publicity stunt for them although a good one. I think it would be a good idea for them to sell software suites of their product if they don't already.
Analytic & algebraic topology of locally Euclidean meterization of infinitely differentiable Riemmanian manifold
As far as I can see, this article says 'We have two arbitary numbers, and one is bigger than the other. From this we deduce that Apache is not as good as commercial software.'
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According to Apache.org, Apache's latest stable version is 2.0.46. Is that a typo on their part, or are they testing a development version? Also, since 1.3.27 is widely used, it would have been interesting to see how that stacked up as well, having been developed longer.
Either way, to have only 31 errors in close to 60,000 lines of code is impressive!
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Since LOC is a poor metric, a "defect density" measurement based on that will be just as poor.
Yes, I know there's not much else to go on, but something along the lines of putting the program through its paces, stress testing, load testing, etc. would be a much better measurement than a metric based on LOC.
Why does it seem a bit odd to be testing software quality with other software? I wonder if they ran their own software through its own program, but then that gets kinda weird when a program starts noticing errors about itself... maybe it'd get depressed and start ranting at the creator on how they should have taken better care of it... ok, I need more sleep
Umm, Apache 2.1 hasn't been released yet. Current latest stable is 2.0.46.
I can only assume that they're looking through the current DEVELOPMENT codebase -- finding a higher ``defect density'' in such a development codebase compared with commercial offerings is not exactly unexpected.
They're also some automated code inspection product; the press release doesn't go into details as to the severity of the defects found or the testing methodology.
It'll be necessary to read through the full report before drawing any sound conclusions.
What bothers me about these articles is that there is more to software quality than the # of flaws-per-unit-"whatever".
Like design.
It seems to me most of the problems with Apache's main competitor in terms of software quality are the result of design and engineering choices made by MS's IIS development team.
In other words, it does exactly what they designed it to do, but what they designed it to do was a very bad idea.
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- Doug McKenzie
The problems with this are:
Kevin Fox
So?
There are errors and there are errors. There are error that don't matter a jot, and there are errors that are show-stoppers.
I've worked on banking software containing code that was written in assembly for PD11s and developed over decades. The most horrible spaggetti code you could ever imagine. Why did the banks keep using it? Because for any particular input it always gave the correct output.
Years of bug fixing had made the code horrible and probably full of errors if you were looking at it from a purely theoretical/software engineering viewpoint. But from an input/output point of view, it was faultless.
First, are all of IIS's issues "software errors" per se? I'm wondering if all security problems would have been caught, or if that was really the goal of the analysis. Perhaps it was, but I'm not sure. One could contest that IIS has a lot of things unprotected, but that this doesn't constitute a software error.
And as you say, severity would be another issue. It's always been typical open-source style to get the mission-critical parts hardened against nuclear attack, but leaving the other bits a tad soft. I wouldn't be surprised to learn that was the case with apache.
One thing I want to know - did MS (or whoever) give these guys source or were they analyzing the binaries?
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Prette lame when we are talking server software where apache has the lead. (apache 63% vs IIS 25% netcraft.com)
/Esben
"Nobody really checks their email any more. They just delete their spam"
Is it just me that finds this entire concept of "code defects per 000 lines" sounding like a little bullshit?
If the company has developed proprietary tools to enable them to identify defects in medium-sized software projects, which of the following business models do you think is more effective:
1. Design proprietary tools to identify defects in medium-sized software projects.
2. Fix defects
3. Profit
or
1. Design proprietary tools to identify defects in medium-sized software projects.
2. Sit around mumbling about defects, Open Source software, closed source software and why farting in the bath smells worse
3. ???
4. Profit
Secondly, where on earth did they get hold of a closed source enterprise level (which Apache undoubtedly is) web server software codebase?
"Hi, is that BEA? Do you mind if we take a copy of your entire code base so that we can peer review it against Apache's? What's that? Yes, Apache might come out on top, and we will make the results public..."
How do they define a defect anyway? A memory leak? A missing overflow check? A tab instead of 4 spaces?
It just sounds like bullshit to me...
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Another post seems to indicate this was done via software to automatically detect defects. Many (most?) security defects cannot be detected automatically, as they involve using the software in an unintended way.
...then why is it their webserver? :)
Of course it is Apache 1.3.23...
is equivalent to the error level in post-release commercial web serving software. Sounds like an endorsement to me.
Also keep in mind that defect density is just an average. If you have 31 defects in 60k lines of code, that is potentially 31 security risks, or out-of-operation risks. If the other software tested had double the lines of code (120k), the density would imply that they had slightly less than double the defects, so say 58 or 60. That implies _58_ potential security or uptime risks. In this case, imho, defect density is not a good indicator of the reliablity of the software.
:)
My general rule is that if someone is quoting statictics to you, they are lying. At least on average.
This doesn't indicate that the commercial equivalents are better. You've got the DEVELOPMENT branch of Apache, which is derrived from the 2.0.x code which is a complete rework from the original 1.X branch of code. So it's a rather new code base and it's showing similar defect rates to a code base that has been around for a while. I'd say this prooves that open source is better.
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The longer and more content you have per line the higher the likelyhood of error/ line.
As example with one errror in 100 lines you get 1% error. Imagine you could do the whole thing in one line. Now you have 100% error.
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I compared this to my 'other' server, for now unnammed.
My 'other' server brought me coffee, 2 pieces toast, 2 eggs OVER EASY, 4 strips of bacon, *and* Smucker's Grape Jelly with nary a mistep, or hesitation. This other server smiled, asked how my wife was, and brought me a new fork when I dropped my first one.
Congratulations, Gloria! You win the 'great server' award!
This article isn't worth the 2 dollar tip.
Why doesn't Reasoning fill the niche, and code a completely error free web server? They know other peoples mistakes, so they should know how to code an error free one.
Well, seriously, I wouldn't put much in their obvious estimation.
Any technology distinguishable from magic, is insufficiently advanced.
Ok, IIS is the obvious choice as being the second most popular web server after Apache. But I hardly think Microsoft will be letting these guys all over the IIS source code.
It could also be Zeus, SunOne or one of the other lesser known web servers out there.
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Some things I found interesting:
One of the explanations (given by Reasoning) for a NULL pointer dereference is "can occur in low memory conditions," which I think means the original allocator did not check for malloc failure.
So you can get a sense of what a defect looks like, here is #21. The orignal uses bold and fonts improve readability, but I don't know how to reproduce that in slashcode:
DEFECT CLASS: Null Pointer Dereference
DEFECT ID 21
LOCATION: httpd-2.1/srclib/apr/misc/unix/otherchild.c : 137
DESCRIPTION The local pointer variable cur, declared on line 126, and assigned on line 128, may
be NULL where it is dereferenced on line 137.
PRECONDITIONS The conditional expression (cur) on line 129 evaluates to false.
This study makes a lot of sense to me - that the defect rate is tied to the maturity of the code base. I have long felt that Microsoft's business model where they redo the operating system in order to churn their user base and induce cash flow will always result in more defects and security problems than a model where software change is driven on a solely technical basis.
I think the next step for these folks would be to take a project that has a long history, say perhaps Apache 1.x and show defect rates over the life of the project.
Well, the reports simply state that, in the 360 files they checked (most of them header files) they found 29 cases of a potential NULL pointer dereference and 2 potentially uninitialized variables. This is from the Apache 2.1 codebase as of 31st Jan this year, about 58k lines of code.
Their automated checker also searched for out-of-bounds array accesses, memory leaks, and bad deallocations. It found none.
They also state that they ran the same checks against other codebases, and found that they did marginally better, on average.
In short, this report says that OLD development code for an unreleased opensource project is nearly as good as current commercial offerings. That's at best, when you consider the huge gamut of possible defects that this checker won't pick up. That margin probably disappears in the +/- of the sampling if you were to do a proper statistical analysis.
The report is fairly useless. It certainly should not be taken as a reason to not trust Apache; to do so would be foolhardy particularly given Apache's track record.
Oh, and Reasoning's webserver is being pounded into the ground. You can get my local copy of the reports from here.
The majority of the secruity holes are from the people setting up the web servers. The holes are usually abused by "wanna-be" hackers, or script-kiddies. The problem is that people are not educated enough to run some of these programs. Being able to understand Apache, and how to make it operate correctly is not everyone's top priority. As long as it works, people don't care how it works (as goes for many other things in this world).
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They make you fill out a form that asks for your email and then do an opt out checkbox at the bottom of the form (you have to check it to NOT get spam from them). The site's a bit slashdotted right now though.
That reminds me of an old (early 1980's) product named BILF (Basic Infinite Loop Finder). It was supposed to be run against BASIC source code and it would find all infinite loops in the code, or so the vendor claimed.
A magazine reviewed the product. In their review they included a formal mathematical proof that such a program could never work. The vendor responded to the proof by saying that they would fix that problem in the next release!
1) Apache 2.1 has more bugs than some unknown commercial competitor. If the version is correct, a development (not-ready-for-release) build was pitted against a released commercial build. Not fair playing ground.
2) Reasoning does not detail the severity or kind of the bugs. Certainly, a web server not being able to handle a type of format (pdf, csv, ogg vorbis) is less severe than a security hole. Pitted against IIS, I would trust Apache even if it had more bugs, because historically it has had fewer security patches. Check out Apache's 2.0 known patches vs IIS 5.0
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As has been pointed out a couple of times in other comments, 2.1 is the development branch of the Apache web server - ie "beta", "buggy", "work in progress", etc. etc. In stead of reading this as "Apache has roughly as many defects as closed source web servers" let's read this as "the development version of Apache has as many defects as... well, some unidentified (beta? shiping?) version of some unknown (iPlanet? IIS?) web server". But you can be *much* more confident that these defects will be fixed in Apache than in the *other* product.
/t
Heck, forget confidence - YOU CAN JUST CHECK.
The fact that Reasoning didn't have to go and get permission from Apache to run this test - coupled with the fact that we don't even know what Apache is being compared to - is the *real* point behind this "article".
ps: IANAL but don't they have to include a copy of the Apache License given that they publish fragments of the source code in their defect report?
#!/usr/bin/english
I suspect the following code will be flagged as a defect:
as long as doOrDie() does its job and never returns a NULL then where's the defect? The guys who wrote this tester seem to want you to check any pointer dereferencing against NULL before use - I might be doing this in my doOrDie() function, I dont want to have to do it twice.Slashdot's summary of this article is way off base, and the article itself couldn't be less useful. Counting the number of "errors" in lines of code... and the ratio is supposed to mean something to us? As compared to unnamed other software? C'mon, I have better things to do with my time.
*plonk*
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First, as many posters have noted, Reasoning DID NOT TEST APACHE 2.1. They tested Apache 2.1-dev. That's dev, as in development branch. As in: I have new untested code, so don't use me on a production server until I'm released in the STABLE series.
For a valid comparison versus commercial software, the testers should have used Apache 2.0.46, the most current STABLE series release.
Second, I'd be interested to see a comparison of 2.0.46 versus 1.3.27. I have a pet theory that multithreaded C code has more bugs than single-threaded C code, and I'd like to see whether there is evidence to support it.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.
One word: architecture.
And not just the architecture of the web server, but the architecture of the entire platform. But specifically looking at the architecture of Apache versus the architecture of IIS, you'll immediately see that the goals of the two pieces of software are not the same. Look at things like IIS's metabase - the structural details of the server's configuration are kept in an in-memory data structure, which is easily modified while the server is running. Apache, in contrast, reads its configuration at startup, and uses it to determine which modules of code are loaded, and how they are used to process requests - fixing the behavior of the web server at startup.
IIS follows typical MS enterprise software design - it has to interface with COM, and the NT security model, and active directory, and the registry, and a million other systems, all in the name of integration, and enterprise management. Apache doesn't have PHBs telling it that it needs another way for the metabase to be edited, or a new instrumentation API, or whatever else a particular large customer asked for - and can get on with just providing its facilities cleanly.
That's why IIS has so many more security holes, even if it does (as may or may not be the case) have the same raw coding error rate as Apache.
MY compiler (Microsoft C++) does catch this
if (myPointer = NULL) {
and issues a warning. Doesn't gcc?
Yes, it does. So does every other C compiler I've ever used (quite a few). I suspect the original poster may be the sort who ignores warnings....
Why?
Am I the only one who looks at reasoning's results with suspicion (even when I agree with them). Any analysis using methods that are not open and repeatable is not science. This just feels like marketing to me. (it is sad because the study of code quality is such a worthwhile pursuit)
they dont say what they used for a comparison.
when they tell us what they used, then I will believe it.
this smells microsoft.
bring it on! we want to know what it was compared against, sure as hell was NOT IIS...