user.rst 2.5 KB

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  1. =================================
  2. Documentation for /proc/sys/user/
  3. =================================
  4. kernel version 4.9.0
  5. Copyright (c) 2016 Eric Biederman <ebiederm@xmission.com>
  6. ------------------------------------------------------------------------------
  7. This file contains the documentation for the sysctl files in
  8. /proc/sys/user.
  9. The files in this directory can be used to override the default
  10. limits on the number of namespaces and other objects that have
  11. per user per user namespace limits.
  12. The primary purpose of these limits is to stop programs that
  13. malfunction and attempt to create a ridiculous number of objects,
  14. before the malfunction becomes a system wide problem. It is the
  15. intention that the defaults of these limits are set high enough that
  16. no program in normal operation should run into these limits.
  17. The creation of per user per user namespace objects are charged to
  18. the user in the user namespace who created the object and
  19. verified to be below the per user limit in that user namespace.
  20. The creation of objects is also charged to all of the users
  21. who created user namespaces the creation of the object happens
  22. in (user namespaces can be nested) and verified to be below the per user
  23. limits in the user namespaces of those users.
  24. This recursive counting of created objects ensures that creating a
  25. user namespace does not allow a user to escape their current limits.
  26. Currently, these files are in /proc/sys/user:
  27. max_cgroup_namespaces
  28. =====================
  29. The maximum number of cgroup namespaces that any user in the current
  30. user namespace may create.
  31. max_ipc_namespaces
  32. ==================
  33. The maximum number of ipc namespaces that any user in the current
  34. user namespace may create.
  35. max_mnt_namespaces
  36. ==================
  37. The maximum number of mount namespaces that any user in the current
  38. user namespace may create.
  39. max_net_namespaces
  40. ==================
  41. The maximum number of network namespaces that any user in the
  42. current user namespace may create.
  43. max_pid_namespaces
  44. ==================
  45. The maximum number of pid namespaces that any user in the current
  46. user namespace may create.
  47. max_time_namespaces
  48. ===================
  49. The maximum number of time namespaces that any user in the current
  50. user namespace may create.
  51. max_user_namespaces
  52. ===================
  53. The maximum number of user namespaces that any user in the current
  54. user namespace may create.
  55. max_uts_namespaces
  56. ==================
  57. The maximum number of user namespaces that any user in the current
  58. user namespace may create.