Re: [PATCH ghak90 V8 11/16] audit: add support for containerid to network namespaces

On Tue, Dec 31, 2019 at 2:51 PM Richard Guy Briggs <rgb(a)redhat.com&gt; 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(a)redhat.com&gt; > Acked-by: Neil Horman <nhorman(a)tuxdriver.com&gt; > Reviewed-by: Ondrej Mosnacek <omosnace(a)redhat.com&gt; > --- > 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)?

> + 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.

paul moore