On 2020-01-22 16:28, Paul Moore wrote: > On Tue, Dec 31, 2019 at 2:51 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > > > > This also adds support to qualify NETFILTER_PKT records. > > > > 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 be 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 > > > > Add audit container identifier auxiliary record(s) to NETFILTER_PKT > > event standalone records. Iterate through all potential audit container > > identifiers associated with a network namespace. > > > > Please see the github audit kernel issue for contid net support: > > https://github.com/linux-audit/audit-kernel/issues/92 > > Please see the github audit testsuiite issue for the test case: > > https://github.com/linux-audit/audit-testsuite/issues/64 > > Please see the github audit wiki for the feature overview: > > https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > > Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx> > > Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx> > > --- > > include/linux/audit.h | 24 +++++++++ > > kernel/audit.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++- > > kernel/nsproxy.c | 4 ++ > > net/netfilter/nft_log.c | 11 +++- > > net/netfilter/xt_AUDIT.c | 11 +++- > > 5 files changed, 176 insertions(+), 6 deletions(-) > > ... > > > diff --git a/include/linux/audit.h b/include/linux/audit.h > > index 5531d37a4226..ed8d5b74758d 100644 > > --- a/include/linux/audit.h > > +++ b/include/linux/audit.h > > @@ -12,6 +12,7 @@ > > #include <linux/sched.h> > > #include <linux/ptrace.h> > > #include <uapi/linux/audit.h> > > +#include <linux/refcount.h> > > > > #define AUDIT_INO_UNSET ((unsigned long)-1) > > #define AUDIT_DEV_UNSET ((dev_t)-1) > > @@ -121,6 +122,13 @@ struct audit_task_info { > > > > extern struct audit_task_info init_struct_audit; > > > > +struct audit_contobj_netns { > > + struct list_head list; > > + u64 id; > > Since we now track audit container IDs in their own structure, why not > link directly to the audit container ID object (and bump the > refcount)? Ok, I've done this but at first I had doubts about the complexity. > > + refcount_t refcount; > > + struct rcu_head rcu; > > +}; > > + > > extern int is_audit_feature_set(int which); > > > > extern int __init audit_register_class(int class, unsigned *list); > > @@ -225,6 +233,12 @@ static inline u64 audit_get_contid(struct task_struct *tsk) > > } > > > > extern void audit_log_container_id(struct audit_context *context, u64 contid); > > +extern void audit_netns_contid_add(struct net *net, u64 contid); > > +extern void audit_netns_contid_del(struct net *net, u64 contid); > > +extern void audit_switch_task_namespaces(struct nsproxy *ns, > > + struct task_struct *p); > > +extern void audit_log_netns_contid_list(struct net *net, > > + struct audit_context *context); > > > > extern u32 audit_enabled; > > > > @@ -297,6 +311,16 @@ static inline u64 audit_get_contid(struct task_struct *tsk) > > > > static inline void audit_log_container_id(struct audit_context *context, u64 contid) > > { } > > +static inline void audit_netns_contid_add(struct net *net, u64 contid) > > +{ } > > +static inline void audit_netns_contid_del(struct net *net, u64 contid) > > +{ } > > +static inline void audit_switch_task_namespaces(struct nsproxy *ns, > > + struct task_struct *p) > > +{ } > > +static inline void audit_log_netns_contid_list(struct net *net, > > + struct audit_context *context) > > +{ } > > > > #define audit_enabled AUDIT_OFF > > > > diff --git a/kernel/audit.c b/kernel/audit.c > > index d4e6eafe5644..f7a8d3288ca0 100644 > > --- a/kernel/audit.c > > +++ b/kernel/audit.c > > @@ -59,6 +59,7 @@ > > #include <linux/freezer.h> > > #include <linux/pid_namespace.h> > > #include <net/netns/generic.h> > > +#include <net/net_namespace.h> > > > > #include "audit.h" > > > > @@ -86,9 +87,13 @@ > > /** > > * struct audit_net - audit private network namespace data > > * @sk: communication socket > > + * @contid_list: audit container identifier list > > + * @contid_list_lock audit container identifier list lock > > */ > > struct audit_net { > > struct sock *sk; > > + struct list_head contid_list; > > + spinlock_t contid_list_lock; > > }; > > > > /** > > @@ -305,8 +310,11 @@ struct audit_task_info init_struct_audit = { > > void audit_free(struct task_struct *tsk) > > { > > struct audit_task_info *info = tsk->audit; > > + struct nsproxy *ns = tsk->nsproxy; > > > > audit_free_syscall(tsk); > > + if (ns) > > + audit_netns_contid_del(ns->net_ns, audit_get_contid(tsk)); > > /* Freeing the audit_task_info struct must be performed after > > * audit_log_exit() due to need for loginuid and sessionid. > > */ > > @@ -409,6 +417,120 @@ static struct sock *audit_get_sk(const struct net *net) > > return aunet->sk; > > } > > > > +void audit_netns_contid_add(struct net *net, u64 contid) > > +{ > > + struct audit_net *aunet; > > + struct list_head *contid_list; > > + struct audit_contobj_netns *cont; > > + > > + if (!net) > > + return; > > + if (!audit_contid_valid(contid)) > > + return; > > + aunet = net_generic(net, audit_net_id); > > + if (!aunet) > > + return; > > + contid_list = &aunet->contid_list; > > + rcu_read_lock(); > > + list_for_each_entry_rcu(cont, contid_list, list) > > + if (cont->id == contid) { > > + spin_lock(&aunet->contid_list_lock); > > + refcount_inc(&cont->refcount); > > + spin_unlock(&aunet->contid_list_lock); > > + goto out; > > + } > > + cont = kmalloc(sizeof(*cont), GFP_ATOMIC); > > + if (cont) { > > + INIT_LIST_HEAD(&cont->list); > > + cont->id = contid; > > + refcount_set(&cont->refcount, 1); > > + spin_lock(&aunet->contid_list_lock); > > + list_add_rcu(&cont->list, contid_list); > > + spin_unlock(&aunet->contid_list_lock); > > + } > > +out: > > + rcu_read_unlock(); > > +} > > See my comments about refcount_t, spinlocks, and list manipulation > races from earlier in the patchset; the same thing applies to the > function above. This was some of the complexity that concerned me, but switching to rcu read locks helped. In this case, since a stale list would cause an update issue and these counts aren't used or updated anywere else, switching to an int makes sense. > paul moore - RGB -- Richard Guy Briggs <rgb@xxxxxxxxxx> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
