Re: New Security Features, Please Comment

David Newall
2008-12-03T06:54:38Z

Geoffrey McRae wrote:
> Right now the only forseeable problem is that if a process holds a fd
> open when the parent app changes its uid/gid, which still, the worst
> that it can do is read/write another user's file.

Well, no, there are more problems than open file descriptors; and the
worst is much worse than reading or writing another user's file.
Suppose you're changing the ids of the Perl, Python or PHP interpreter:
the first user could install a SIGCLD handler and fork and exec sleep.
When sleep dies, the handler gets executed as another user - hopefully a
user with access to credit card details, or other financially valuable
information.