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..."

Comments

more to it than # flaws-per-unit-"whatever"

[Asprin]

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.

No cigar, my ass.

[KFury]

The article claims Apache's error density, based on a meager 5100 lines of code, is 0.53, while that of 'comparable commercial applications' is 0.51.

The problems with this are:

• 5100 lines of code does not give you a confidence range of less than 0.02, especially when the error rate can be expected to be heterogeneous across the code base, as would be the case in an open-source product where different code pieces are created by entirely different groups.
• 'Comparable' my ass. If they can't provide details of what software they're comparing to (I somehow doubt they got a look at IIS source code) then the stats are worthless, because anyone who's ever programmed knows that quality control isn't a constant factor across commercial products any more than it is among open-source products.
• What's the error rate of their 'defect analysis'? If they're so good at finding defects, why aren't they out there writing perfect software? If their defect detection rate is less than 98% accurate, then the difference between a rate of 0.51 and 0.53 is meaningless anyhow.
• There's a big difference between caught coding exceptions and fundamental security problems. The first can cause code to run a little slower, the second can destroy your company. This testing methodology doesn't even look at the second.

what is a "software error"?

[siskbc]

If Apache and, say, IIS are roughly equivalent in terms of code defects, you have to ask yourself "well, why does IIS have so many more general problems and security flaws then Apache, when they both carry the same general amount of coding defects?". Is IIS just inherinetly insucure because it is used on a Windows platform? Is it because hackers generally target IIS and not Apache (most people will rush to this conclusion)?

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?

Different standards?

[NotClever]

When the same group said that the IP stack in Linux was cleaner than a comparable one, everyone was screaming from the rooftops that it validated the open source model. When they say that an open source project and a closed source project are roughly comparable, all of a sudden everyone criticizes the methodology of the report!

automatically detected defects exclude security

[brlewis]

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.

Bad Statistics...

[FunkZombie]

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. :)

Don't assume IIS

[m00nun1t]

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.

Re:Code defects appear to be a small part of the e

[jdh-22]

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.

To quote Bruce Schneier: "If I had a letter, sealed it in a locked vault and hid the vault somewhere in New York. Then told you to read the letter, thats not secruity, thats obsecurity. If I made a letter, sealed it in a vault, gave you the blueprints of the vault, the combinations of 1000 other vaults, access to the best lock smiths in the world, then told you to read the letter, and you still can't, thats security." Open source does have an upper hand on holes and bugs, but the code isn't where we should be looking.

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).

Re:So if they found them...

[Anonymous Coward]

The funny thing is that this "bug" doesn't appear to actually be one...

Note that current_provider is set to conf->providers on line 257. The loop starts and neither current_provider or conf->providers change. Then on line 287 there's a conditional break if conf->providers is NULL.

If current_provider is going to be NULL at line 291, then conf->providers must be as well, so the conditional break will happen and the NULL dereference will be skipped.

Or am I missing something else?