devcgroup: fix odd behaviour when writing 'a' to devices.allow

# cat /devcg/devices.list
 a *:* rwm
 # echo a > devices.allow
 # cat /devcg/devices.list
 a *:* rwm
 a 0:0 rwm

This is odd and maybe confusing.  With this patch, writing 'a' to
devices.allow will add 'a *:* rwm' to the whitelist.

Also a few fixes and updates to the document.

Signed-off-by: Li Zefan <[email protected]>
Cc: Pavel Emelyanov <[email protected]>
Cc: Serge E. Hallyn <[email protected]>
Cc: Paul Menage <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: James Morris <[email protected]>
Cc: Chris Wright <[email protected]>
Cc: Stephen Smalley <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Li Zefan 2008-07-04 10:00:07 -07:00 • committed by Linus Torvalds
commit d823f6bfec
2 changed files with 8 additions and 2 deletions

View file

@ -13,7 +13,7 @@ either an integer or * for all. Access is a composition of r
The root device cgroup starts with rwm to 'all'. A child device
cgroup gets a copy of the parent. Administrators can then remove
devices from the whitelist or add new entries. A child cgroup can
never receive a device access which is denied its parent. However
never receive a device access which is denied by its parent. However
when a device access is removed from a parent it will not also be
removed from the child(ren).
@ -29,7 +29,11 @@ allows cgroup 1 to read and mknod the device usually known as
echo a > /cgroups/1/devices.deny
will remove the default 'a *:* mrw' entry.
will remove the default 'a *:* rwm' entry. Doing
echo a > /cgroups/1/devices.allow
will add the 'a *:* rwm' entry to the whitelist.
3. Security