On Tue, Jul 31, 2018 at 4:12 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > Audit events could happen in a network namespace outside of a task > context due to packets received from the net that trigger an auditing > rule prior to being associated with a running task. The network > namespace could in use by multiple containers by association to the > tasks in that network namespace. We still want a way to attribute > these events to any potential containers. Keep a list per network > namespace to track these audit container identifiiers. > > Add/increment the audit container identifier on: > - initial setting of the audit container identifier via /proc > - clone/fork call that inherits an audit container identifier > - unshare call that inherits an audit container identifier > - setns call that inherits an audit container identifier > Delete/decrement the audit container identifier on: > - an inherited audit container identifier dropped when child set > - process exit > - unshare call that drops a net namespace > - setns call that drops a net namespace > > See: https://github.com/linux-audit/audit-kernel/issues/92 > See: https://github.com/linux-audit/audit-testsuite/issues/64 > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > --- > include/linux/audit.h | 17 ++++++++++ > kernel/audit.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++ > kernel/auditsc.c | 8 ++++- > kernel/nsproxy.c | 4 +++ > 4 files changed, 114 insertions(+), 1 deletion(-) ... > @@ -308,6 +312,86 @@ static struct sock *audit_get_sk(const struct net *net) > return aunet->sk; > } > > +/** > + * audit_get_netns_contid_list - Return the audit container ID list for the given network namespace > + * @net: the destination network namespace > + * > + * Description: > + * Returns the list pointer if valid, NULL otherwise. The caller must ensure > + * that a reference is held for the network namespace while the sock is in use. > + */ > +struct list_head *audit_get_netns_contid_list(const struct net *net) > +{ > + struct audit_net *aunet = net_generic(net, audit_net_id); > + > + return &aunet->contid_list; > +} > + > +spinlock_t *audit_get_netns_contid_list_lock(const struct net *net) > +{ > + struct audit_net *aunet = net_generic(net, audit_net_id); > + > + return &aunet->contid_list_lock; > +} Instead of returning the spinlock, just do away with the audit_get_ns_contid_list_lock() function and create two separate lock and unlock functions that basically do the net_generic() and spinlock operations together, for example: static int audit_netns_contid_lock(const struct net *net) { aunet = net_generic(net, audit_net_id); if (!aunet) return -whatever; spin_lock(aunet->lock); return 0; } > +void audit_netns_contid_add(struct net *net, u64 contid) > +{ > + spinlock_t *lock = audit_get_netns_contid_list_lock(net); > + struct list_head *contid_list = audit_get_netns_contid_list(net); > + struct audit_contid *cont; > + > + if (!audit_contid_valid(contid)) > + return; > + spin_lock(lock); > + if (!list_empty(contid_list)) > + list_for_each_entry(cont, contid_list, list) > + if (cont->id == contid) { > + refcount_inc(&cont->refcount); > + goto out; > + } > + cont = kmalloc(sizeof(struct audit_contid), GFP_KERNEL); > + if (cont) { > + INIT_LIST_HEAD(&cont->list); > + cont->id = contid; > + refcount_set(&cont->refcount, 1); > + list_add(&cont->list, contid_list); > + } > +out: > + spin_unlock(lock); > +} > + > +void audit_netns_contid_del(struct net *net, u64 contid) > +{ > + spinlock_t *lock = audit_get_netns_contid_list_lock(net); > + struct list_head *contid_list = audit_get_netns_contid_list(net); > + struct audit_contid *cont = NULL; > + > + if (!audit_contid_valid(contid)) > + return; > + spin_lock(lock); > + if (!list_empty(contid_list)) > + list_for_each_entry(cont, contid_list, list) > + if (cont->id == contid) { > + list_del(&cont->list); > + if (refcount_dec_and_test(&cont->refcount)) > + kfree(cont); > + break; > + } > + spin_unlock(lock); > +} > + > +void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p) > +{ > + u64 contid = audit_get_contid(p); > + struct nsproxy *new = p->nsproxy; > + > + if (!audit_contid_valid(contid)) > + return; > + audit_netns_contid_del(ns->net_ns, contid); > + if (new) > + audit_netns_contid_add(new->net_ns, contid); > +} > + > void audit_panic(const char *message) > { > switch (audit_failure) { > @@ -1547,6 +1631,8 @@ static int __net_init audit_net_init(struct net *net) > return -ENOMEM; > } > aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; > + INIT_LIST_HEAD(&aunet->contid_list); > + spin_lock_init(&aunet->contid_list_lock); > > return 0; > } > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 610c6869..fdf3f68 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -75,6 +75,7 @@ > #include <linux/uaccess.h> > #include <linux/fsnotify_backend.h> > #include <uapi/linux/limits.h> > +#include <net/net_namespace.h> > > #include "audit.h" > > @@ -2165,6 +2166,7 @@ int audit_set_contid(struct task_struct *task, u64 contid) > uid_t uid; > struct tty_struct *tty; > char comm[sizeof(current->comm)]; > + struct net *net = task->nsproxy->net_ns; > > task_lock(task); > /* Can't set if audit disabled */ > @@ -2186,8 +2188,12 @@ int audit_set_contid(struct task_struct *task, u64 contid) > else if (!(thread_group_leader(task) && thread_group_empty(task))) > rc = -EALREADY; > read_unlock(&tasklist_lock); > - if (!rc) > + if (!rc) { > + if (audit_contid_valid(oldcontid)) > + audit_netns_contid_del(net, oldcontid); > task->audit->contid = contid; > + audit_netns_contid_add(net, contid); > + } > task_unlock(task); > > if (!audit_enabled) > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c > index f6c5d33..718b120 100644 > --- a/kernel/nsproxy.c > +++ b/kernel/nsproxy.c > @@ -27,6 +27,7 @@ > #include <linux/syscalls.h> > #include <linux/cgroup.h> > #include <linux/perf_event.h> > +#include <linux/audit.h> > > static struct kmem_cache *nsproxy_cachep; > > @@ -140,6 +141,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) > struct nsproxy *old_ns = tsk->nsproxy; > struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); > struct nsproxy *new_ns; > + u64 contid = audit_get_contid(tsk); > > if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | > CLONE_NEWPID | CLONE_NEWNET | > @@ -167,6 +169,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) > return PTR_ERR(new_ns); > > tsk->nsproxy = new_ns; > + audit_netns_contid_add(new_ns->net_ns, contid); > return 0; > } > > @@ -224,6 +227,7 @@ void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) > ns = p->nsproxy; > p->nsproxy = new; > task_unlock(p); > + audit_switch_task_namespaces(ns, p); > > if (ns && atomic_dec_and_test(&ns->count)) > free_nsproxy(ns); -- paul moore www.paul-moore.com
