Re: [PATCH ghak90 V8 12/16] audit: contid check descendancy and nesting

Require the target task to be a descendant of the container orchestrator/engine. You would only change the audit container ID from one set or inherited value to another if you were nesting containers. If changing the contid, the container orchestrator/engine must be a descendant and not same orchestrator as the one that set it so it is not possible to change the contid of another orchestrator's container. Since the task_is_descendant() function is used in YAMA and in audit, remove the duplication and pull the function into kernel/core/sched.c Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; --- include/linux/sched.h | 3 +++ kernel/audit.c | 44 ++++++++++++++++++++++++++++++++++++-------- kernel/sched/core.c | 33 +++++++++++++++++++++++++++++++++ security/yama/yama_lsm.c | 33 --------------------------------- 4 files changed, 72 insertions(+), 41 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c index f7a8d3288ca0..ef8e07524c46 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -2603,22 +2610,43 @@ int audit_set_contid(struct task_struct *task, u64 contid) oldcontid = audit_get_contid(task); read_lock(&tasklist_lock); /* Don't allow the contid to be unset */ - if (!audit_contid_valid(contid)) + if (!audit_contid_valid(contid)) { rc = -EINVAL; + goto unlock; + } /* Don't allow the contid to be set to the same value again */ - else if (contid == oldcontid) { + if (contid == oldcontid) { rc = -EADDRINUSE; + goto unlock; + } /* if we don't have caps, reject */ - else if (!capable(CAP_AUDIT_CONTROL)) + if (!capable(CAP_AUDIT_CONTROL)) { rc = -EPERM; - /* if task has children or is not single-threaded, deny */ - else if (!list_empty(&task->children)) + goto unlock; + } + /* if task has children, deny */ + if (!list_empty(&task->children)) { rc = -EBUSY; - else if (!(thread_group_leader(task) && thread_group_empty(task))) + goto unlock; + } + /* if task is not single-threaded, deny */ + if (!(thread_group_leader(task) && thread_group_empty(task))) { rc = -EALREADY; - /* if contid is already set, deny */ - else if (audit_contid_set(task)) + goto unlock; + }

+ /* if task is not descendant, block */ + if (task == current) { + rc = -EBADSLT; + goto unlock; + } + if (!task_is_descendant(current, task)) { + rc = -EXDEV; + goto unlock; + }

+ /* only allow contid setting again if nesting */ + if (audit_contid_set(task) && audit_contid_isowner(task)) rc = -ECHILD;