One of the headline features in the 3.6 release was the long-awaited advent
of security restrictions
that change the
handling of hard and soft links in world-writable directories. One of the
reasons this change took so long to merge was concerns about breaking
programs and scripts on user systems. The case was finally made that
problems would be limited to malware, and the feature was merged.
Now, a single report of trouble on the
linux-kernel list has developers questioning the change — or, at least,
whether it should be turned on by default. Linus fears that this report could be followed by
However, I suspect we'll see more. And once that happens, we're not
going to keep a default that breaks peoples old scripts, and we're
going to have to rely on distributions (or users) explicitly
Compatibility is just too important.
Other developers have argued for making the
change as soon as the 3.6.1 stable update. Needless to say, agreement on
this point is not universal; Kees Cook, the author of the change, argues that the benefits far outweigh the
pain. The kernel community is committed to not breaking things that used
to work, though; if this change appears to be causing problems more widely,
it will probably be reversed in the near future.
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