path: root/init/Kconfig
diff options
authorSerge E. Hallyn <>2008-04-29 01:00:10 -0700
committerLinus Torvalds <>2008-04-29 08:06:09 -0700
commit08ce5f16ee466ffc5bf243800deeecd77d9eaf50 (patch)
tree8fb921137a677d463f11727dab7e683db426b810 /init/Kconfig
parentd447ea2f30ec60370ddb99a668e5ac12995f043d (diff)
cgroups: implement device whitelist
Implement a cgroup to track and enforce open and mknod restrictions on device files. A device cgroup associates a device access whitelist with each cgroup. A whitelist entry has 4 fields. 'type' is a (all), c (char), or b (block). 'all' means it applies to all types and all major and minor numbers. Major and minor are either an integer or * for all. Access is a composition of r (read), w (write), and m (mknod). The root device cgroup starts with rwm to 'all'. A child devcg gets a copy of the parent. Admins 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 when a device access is removed from a parent it will not also be removed from the child(ren). An entry is added using devices.allow, and removed using devices.deny. For instance echo 'c 1:3 mr' > /cgroups/1/devices.allow allows cgroup 1 to read and mknod the device usually known as /dev/null. Doing echo a > /cgroups/1/devices.deny will remove the default 'a *:* mrw' entry. CAP_SYS_ADMIN is needed to change permissions or move another task to a new cgroup. A cgroup may not be granted more permissions than the cgroup's parent has. Any task can move itself between cgroups. This won't be sufficient, but we can decide the best way to adequately restrict movement later. [ coding-style fixes] [ fix may-be-used-uninitialized warning] Signed-off-by: Serge E. Hallyn <> Acked-by: James Morris <> Looks-good-to: Pavel Emelyanov <> Cc: Daniel Hokka Zakrisson <> Cc: Li Zefan <> Cc: Paul Menage <> Cc: Balbir Singh <> Cc: KAMEZAWA Hiroyuki <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'init/Kconfig')
1 files changed, 7 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 6ce16bdbec76..a3457926342a 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -298,6 +298,13 @@ config CGROUP_NS
for instance virtual servers and checkpoint/restart
+ bool "Device controller for cgroups"
+ help
+ Provides a cgroup implementing whitelists for devices which
+ a process in the cgroup can mknod or open.
config CPUSETS
bool "Cpuset support"
depends on SMP && CGROUPS