Messages in this thread | | | Date | Tue, 22 May 2012 08:34:34 +0800 | From | Li Zefan <> | Subject | Re: [PATCH] cgroup: fix device deny of DEV_ALL |
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Serge Hallyn wrote:
> Quoting Amos Kong (akong@redhat.com): >> @ mount -t cgroup -o devices none /cgroup >> @ mkdir /cgroups/devices >> @ ls -l /dev/dm-3 >> brw-rw----. 1 root disk 253, 3 Oct 14 19:03 /dev/dm-3 >> @ echo 'b 253:3 rw' > devices.deny >> but I can still write it by 'dd if=/dev/zero of=/dev/dm-3' >> >> In devcgroup_create(), we create a new whitelist, and add first >> entry which type is 'DEV_ALL'. Execute "# echo 'b 253:3 rw' > >> devices.deny", dev_whitelist_rm() will update access of first >> entry to 1(m), but type of first entry is still 'DEV_ALL'. > > Hi, > > thanks. You raise a good point, but I think it needs some discussion. > > What happens right now is that if you have the 'a *:* rwm' entry and do > echo 'b 253:3 rw' > devices.deny, then when you next cat devices.list you > will still see the 'a *:* rwm' entry. So there should be no confusion > over why the dd succeeds. You didn't remove the entry, because there > was no match echoed into devices.deny.
No, you'll see the entry has been changed to 'a *:* m', so I think we should at least fix this.
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