On 2018-04-18 21:46, Paul Moore wrote: > On Fri, Mar 16, 2018 at 5:00 AM, 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 container identifiiers. > > > > Add/increment the container identifier on: > > - initial setting of the container id via /proc > > - clone/fork call that inherits a container identifier > > - unshare call that inherits a container identifier > > - setns call that inherits a container identifier > > Delete/decrement the container identifier on: > > - an inherited container id 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/32 > > See: https://github.com/linux-audit/audit-testsuite/issues/64 > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > > --- > > include/linux/audit.h | 7 +++++++ > > include/net/net_namespace.h | 12 ++++++++++++ > > kernel/auditsc.c | 9 ++++++--- > > kernel/nsproxy.c | 6 ++++++ > > net/core/net_namespace.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ > > 5 files changed, 76 insertions(+), 3 deletions(-) > > ... > > > diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h > > index 0490084..343a428 100644 > > --- a/include/net/net_namespace.h > > +++ b/include/net/net_namespace.h > > @@ -33,6 +33,7 @@ > > #include <linux/ns_common.h> > > #include <linux/idr.h> > > #include <linux/skbuff.h> > > +#include <linux/audit.h> > > > > struct user_namespace; > > struct proc_dir_entry; > > @@ -150,6 +151,7 @@ struct net { > > #endif > > struct sock *diag_nlsk; > > atomic_t fnhe_genid; > > + struct list_head audit_containerid; > > } __randomize_layout; > > We talked about this briefly off-list, you should be using audit_net > and the net_generic mechanism instead of this. > > > #include <linux/seq_file_net.h> > > @@ -301,6 +303,16 @@ static inline struct net *read_pnet(const possible_net_t *pnet) > > #define __net_initconst __initconst > > #endif > > > > +#ifdef CONFIG_NET_NS > > +void net_add_audit_containerid(struct net *net, u64 containerid); > > +void net_del_audit_containerid(struct net *net, u64 containerid); > > +#else > > +static inline void net_add_audit_containerid(struct net *, u64) > > +{ } > > +static inline void net_del_audit_containerid(struct net *, u64) > > +{ } > > +#endif > > + > > int peernet2id_alloc(struct net *net, struct net *peer); > > int peernet2id(struct net *net, struct net *peer); > > bool peernet_has_id(struct net *net, struct net *peer); > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > index 2f02ed9..208da962 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" > > > > @@ -2175,16 +2176,18 @@ static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainer > > */ > > int audit_set_containerid(struct task_struct *task, u64 containerid) > > { > > - u64 oldcontainerid; > > + u64 oldcontainerid = audit_get_containerid(task); > > int rc; > > - > > - oldcontainerid = audit_get_containerid(task); > > + struct net *net = task->nsproxy->net_ns; > > > > rc = audit_set_containerid_perm(task, containerid); > > if (!rc) { > > + if (cid_valid(oldcontainerid)) > > + net_del_audit_containerid(net, oldcontainerid); > > Using audit_net we can handle this internal to audit, which is a Good Thing. No problem, done. > > task_lock(task); > > task->containerid = containerid; > > task_unlock(task); > > + net_add_audit_containerid(net, containerid); > > Same. > > > } > > > > audit_log_set_containerid(task, oldcontainerid, containerid, rc); > > diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c > > index f6c5d33..d9f1090 100644 > > --- a/kernel/nsproxy.c > > +++ b/kernel/nsproxy.c > > @@ -140,6 +140,7 @@ 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 containerid = audit_get_containerid(tsk); > > > > if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | > > CLONE_NEWPID | CLONE_NEWNET | > > @@ -167,6 +168,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) > > return PTR_ERR(new_ns); > > > > tsk->nsproxy = new_ns; > > + net_add_audit_containerid(new_ns->net_ns, containerid); > > return 0; > > } > > Hopefully we can handle this in audit_net_init(), we just need to > figure out where we can get the correct task_struct for the audit > container ID (some backpointer in the net struct?). I don't follow. This needs to happen on every task startup. audit_net_init() is only called when a new network namespace starts up. > > @@ -217,6 +219,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags, > > void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) > > { > > struct nsproxy *ns; > > + u64 containerid = audit_get_containerid(p); > > > > might_sleep(); > > > > @@ -224,6 +227,9 @@ void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) > > ns = p->nsproxy; > > p->nsproxy = new; > > task_unlock(p); > > + net_del_audit_containerid(ns->net_ns, containerid); > > + if (new) > > + net_add_audit_containerid(new->net_ns, containerid); > > Okay, we might need a hook here for switching namespaces, but I would > much rather it be a generic audit hook that calls directly into audit. Trivial, done. > 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
