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| -rw-r--r-- | Documentation/namespaces/resource-control.txt | 14 | ||||
| -rw-r--r-- | init/Kconfig | 7 |
2 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/namespaces/resource-control.txt b/Documentation/namespaces/resource-control.txt new file mode 100644 index 00000000000..abc13c39473 --- /dev/null +++ b/Documentation/namespaces/resource-control.txt @@ -0,0 +1,14 @@ +There are a lot of kinds of objects in the kernel that don't have +individual limits or that have limits that are ineffective when a set +of processes is allowed to switch user ids. With user namespaces +enabled in a kernel for people who don't trust their users or their +users programs to play nice this problems becomes more acute. + +Therefore it is recommended that memory control groups be enabled in +kernels that enable user namespaces, and it is further recommended +that userspace configure memory control groups to limit how much +memory user's they don't trust to play nice can use. + +Memory control groups can be configured by installing the libcgroup +package present on most distros editing /etc/cgrules.conf, +/etc/cgconfig.conf and setting up libpam-cgroup. diff --git a/init/Kconfig b/init/Kconfig index 7d30240e5bf..c8c58bddfed 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1035,6 +1035,13 @@ config USER_NS help This allows containers, i.e. vservers, to use user namespaces to provide different user info for different servers. + + When user namespaces are enabled in the kernel it is + recommended that the MEMCG and MEMCG_KMEM options also be + enabled and that user-space use the memory control groups to + limit the amount of memory a memory unprivileged users can + use. + If unsure, say N. config PID_NS |