Messages in this thread | | | Date | Thu, 10 Sep 1998 08:00:52 -0400 | From | Bill Hawes <> | Subject | Re: [Question] mount points on knfsd. |
| |
Alan Cox wrote: > > > But it is not clear what it should do. The problem with what nfsd > > does now is that it returns an EACCESS (-13) error when you LOOKUP > > the mount point, and mount with not let you mount onto that directory. > > > > There seem to be several possible solutions: > > > > 1) return the underlying directory. This should be easy; you can use > > dchild->d_covers in fs/nfsd/vfs.c line 176. > > That would work. And the underlying directory is on the right file system > so would have a valid inode for that fs
Returning the underlying directory avoids inode aliasing problems, but is otherwise a security problem in that it exposes part of a filesystem not otherwise visible. (How many sysadmins know what's below the mountpoints for something that's routinely coverd?)
This issue has come up several times before, and people have sent in patches to let nfsd access the underlying directory. I don't think it's a good thing to do though.
What would be acceptable is to allow the mounted-over inode to be visible, but nothing further, so that it could become a mountpoint but not serve to access any normally invisible directories.
Regards, Bill
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/faq.html
| |