flink() flunks

A few weeks back, we noted the merging of a patch adding support for the flink() system call, which would allow a program to link to a file represented by an open file descriptor. This functionality had long been blocked as the result of security worries; it went through this time on the argument that the kernel already provided that feature via the linkat() call. At that point, it seemed like this feature was set for the 3.11 kernel.

Not everybody was convinced, though; in particular, Brad Spengler apparently raised the issue of processes making links to file descriptors that had been passed in from a more privileged domain. So Andy Lutomirski, the author of the original patch, posted a followup to restrict the functionality to files created with the O_TMPFILE option. The only problem was that nobody much liked the patch; Linus was reasonably clear about his feelings.

What followed was a long discussion on how to better solve the problem, with a number of patches going back and forth. About the only thing that became clear was that the best solution was not yet clear. So, on August 28, Linus reverted the original patch, saying "Clearly we're not done with this discussion, and the patches flying around aren't appropriate for 3.11" So the flink() functionality will have to wait until at least 3.12.

---

(Log in to post comments)