Re: Chroot bug

On Wednesday 26 September 2007 13:06:51 David Newall wrote:
Alan Cox wrote:
The dot-dot entry in the root directory is interpreted to mean the
root directory itself. Thus, dot-dot cannot be used to access files
outside the subtree rooted at the root directory.

Which is behaviour chroot preserves properly.

And yet it is the dot-dot entry which is used to access files outside
the root.

The specification says explicitly

"The process working directory is unaffected by chroot()."

Do you believe that when those words were first written, the hidden
conflict, namely that it permits dot-dot to access files outside the
subtree, was understood? They would have said so if that were the case.

You seem to be misunderstanding what Alan is trying to say to you, if your
program calls chroot, it's working directory is unaffected. Programs that are
started in the chrooted root, will be affected.

i.e. if you run chroot in bash, the bash process's CWD is not affected and
bash can escape the chrooted root, but if you run ls .., it will not escape.

If you do not get too emotional, you tend to understand what people are trying
to say.
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