Messages in this thread |  | | Date | Tue, 13 Jul 2010 23:53:37 -0700 | From | Kees Cook <> | Subject | Re: [PATCH] Yama: verify inode is symlink to avoid bind mounts |
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On Tue, Jul 13, 2010 at 09:30:48PM -0500, Serge E. Hallyn wrote: > Quoting Kees Cook (kees.cook@canonical.com): > > The inode_follow_link LSM hook is called in bind mount situations as > > well as for symlink situations, so we must explicitly check for the > > inode being a symlink to not reject bind mounts in 1777 directories, > > Are you sure about that?? > > If that's true, you might also expand the comment in > include/linux/security.h. > > > which seems to be a common NFSv4 configuration.
Well, the issue is how the NFSv4 client deals with it. It seems to treat the mounts from the NFSv4 root as a symlink when the server is using bind mounts. It's kind of weird: https://launchpad.net/bugs/604407
-- Kees Cook Ubuntu Security Team
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