diff options
Diffstat (limited to 'Documentation/sysctl')
| -rw-r--r-- | Documentation/sysctl/README | 1 | ||||
| -rw-r--r-- | Documentation/sysctl/user.txt | 66 |
2 files changed, 67 insertions, 0 deletions
diff --git a/Documentation/sysctl/README b/Documentation/sysctl/README index 8c3306e01d52..91f54ffa0077 100644 --- a/Documentation/sysctl/README +++ b/Documentation/sysctl/README @@ -69,6 +69,7 @@ proc/ <empty> sunrpc/ SUN Remote Procedure Call (NFS) vm/ memory management tuning buffer and cache management +user/ Per user per user namespace limits These are the subdirs I have on my system. There might be more or other subdirs in another setup. If you see another dir, I'd diff --git a/Documentation/sysctl/user.txt b/Documentation/sysctl/user.txt new file mode 100644 index 000000000000..1291c498f78f --- /dev/null +++ b/Documentation/sysctl/user.txt @@ -0,0 +1,66 @@ +Documentation for /proc/sys/user/* kernel version 4.9.0 + (c) 2016 Eric Biederman <ebiederm@xmission.com> + +============================================================== + +This file contains the documetation for the sysctl files in +/proc/sys/user. + +The files in this directory can be used to override the default +limits on the number of namespaces and other objects that have +per user per user namespace limits. + +The primary purpose of these limits is to stop programs that +malfunction and attempt to create a ridiculous number of objects, +before the malfunction becomes a system wide problem. It is the +intention that the defaults of these limits are set high enough that +no program in normal operation should run into these limits. + +The creation of per user per user namespace objects are charged to +the user in the user namespace who created the object and +verified to be below the per user limit in that user namespace. + +The creation of objects is also charged to all of the users +who created user namespaces the creation of the object happens +in (user namespaces can be nested) and verified to be below the per user +limits in the user namespaces of those users. + +This recursive counting of created objects ensures that creating a +user namespace does not allow a user to escape their current limits. + +Currently, these files are in /proc/sys/user: + +- max_cgroup_namespaces + + The maximum number of cgroup namespaces that any user in the current + user namespace may create. + +- max_ipc_namespaces + + The maximum number of ipc namespaces that any user in the current + user namespace may create. + +- max_mnt_namespaces + + The maximum number of mount namespaces that any user in the current + user namespace may create. + +- max_net_namespaces + + The maximum number of network namespaces that any user in the + current user namespace may create. + +- max_pid_namespaces + + The maximum number of pid namespaces that any user in the current + user namespace may create. + +- max_user_namespaces + + The maximum number of user namespaces that any user in the current + user namespace may create. + +- max_uts_namespaces + + The maximum number of user namespaces that any user in the current + user namespace may create. |