Karel Zak wrote on 10/30/2015 11:22 AM:
On Fri, Oct 30, 2015 at 03:09:15AM +0100, U.Mutlu wrote:
Hi,
I wonder why "unshare -m" doesn't work for an unpriviledged user:
$ unshare -m /bin/bash
unshare: unshare failed: Operation not permitted
$ echo $?
1
$ ls -l `which unshare`
-rwxr-xr-x 1 root root 14640 Mar 30 2015 /usr/bin/unshare
Funny thing: when making the binary setuid then it works.
But I would prefer a working original version in the OS repository.
OS: Debian 8
# dpkg -l | grep -i util-linux
ii util-linux 2.25.2-6 amd64
Miscellaneous system utilities
Is this a bug, or is it not supposed to work for non-root users?
man 2 unshare:
CLONE_NEWNS
This flag has the same effect as the clone(2) CLONE_NEWNS flag.
Unshare the mount namespace, so that the calling process has a private
copy of its namespace which is not shared with any other process.
Specifying this flag automatically implies CLONE_FS as well. Use of
CLONE_NEWNS requires the CAP_SYS_ADMIN capability.
^^^^^^^^^^^^
.. so yes, it's expected behavior.
Karel
I would say that the bug lies in the wrong file permissions.
chmod u+s fixes the bug, and I suggest that this should be the default.
Then non-root users can use it too.
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