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/linux/audit.h b/include/linux/audit.h index c0b83cb..d9afb7d 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -26,6 +26,7 @@ #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) @@ -88,6 +89,12 @@ struct audit_field { u32 op; }; +struct audit_containerid { + struct list_head list; + u64 id; + refcount_t refcount; +}; + extern int is_audit_feature_set(int which); extern int __init audit_register_class(int class, unsigned *list); 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; #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); task_lock(task); task->containerid = containerid; task_unlock(task); + net_add_audit_containerid(net, containerid); } 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; } @@ -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); if (ns && atomic_dec_and_test(&ns->count)) free_nsproxy(ns); diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 60a71be7..ae30d33 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -22,6 +22,7 @@ #include <net/netlink.h> #include <net/net_namespace.h> #include <net/netns/generic.h> +#include <linux/nsproxy.h> /* * Our network namespace constructor/destructor lists @@ -290,6 +291,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) net->user_ns = user_ns; idr_init(&net->netns_ids); spin_lock_init(&net->nsid_lock); + INIT_LIST_HEAD(&net->audit_containerid); list_for_each_entry(ops, &pernet_list, list) { error = ops_init(ops, net); @@ -1067,6 +1069,49 @@ void unregister_pernet_device(struct pernet_operations *ops) EXPORT_SYMBOL_GPL(unregister_pernet_device); #ifdef CONFIG_NET_NS +void net_add_audit_containerid(struct net *net, u64 containerid) +{ + struct audit_containerid *cont; + + if (!cid_valid(containerid)) + return; + if (!list_empty(&net->audit_containerid)) + list_for_each_entry(cont, &net->audit_containerid, list) + if (cont->id == containerid) { + refcount_inc(&cont->refcount); + return; + } + cont = kmalloc(sizeof(struct audit_containerid), GFP_KERNEL); + if (!cont) + return; + INIT_LIST_HEAD(&cont->list); + cont->id = containerid; + refcount_set(&cont->refcount, 1); + list_add(&cont->list, &net->audit_containerid); +} + +void net_del_audit_containerid(struct net *net, u64 containerid) +{ + struct audit_containerid *cont = NULL; + int found = 0; + + if (!cid_valid(containerid)) + return; + if (!list_empty(&net->audit_containerid)) + list_for_each_entry(cont, &net->audit_containerid, list) + if (cont->id == containerid) { + found = 1; + break; + } + if (!found) + return; + list_del(&cont->list); + if (refcount_dec_and_test(&cont->refcount)) + kfree(cont); +} +#endif + +#ifdef CONFIG_NET_NS static struct ns_common *netns_get(struct task_struct *task) { struct net *net = NULL; -- 1.8.3.1
