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 <[email protected]> --- include/linux/audit.h | 23 ++++++++++++++++ kernel/audit.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++ kernel/auditsc.c | 5 ++++ kernel/nsproxy.c | 4 +++ 4 files changed, 104 insertions(+) diff --git a/include/linux/audit.h b/include/linux/audit.h index 1e37abf..7e2e51c 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) @@ -87,6 +88,12 @@ struct audit_field { u32 op; }; +struct audit_contid { + 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); @@ -156,6 +163,10 @@ extern void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk); extern int audit_log_contid(struct audit_context *context, char *op, u64 contid); +extern struct list_head *audit_get_contid_list(const struct net *net); +extern void audit_contid_add(struct net *net, u64 contid); +extern void audit_contid_del(struct net *net, u64 contid); +extern void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p); extern int audit_update_lsm_rules(void); @@ -209,6 +220,18 @@ static inline void audit_log_task_info(struct audit_buffer *ab, static inline int audit_log_contid(struct audit_context *context, char *op, u64 contid) { } +static inline struct list_head *audit_get_contid_list(const struct net *net) +{ + static LIST_HEAD(list); + return &list; +} +static inline void audit_contid_add(struct net *net, u64 contid) +{ } +static inline void audit_contid_del(struct net *net, u64 contid) +{ } +static inline void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p) +{ } + #define audit_enabled 0 #endif /* CONFIG_AUDIT */ diff --git a/kernel/audit.c b/kernel/audit.c index ba304a8..ecd2de4 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -106,6 +106,7 @@ */ struct audit_net { struct sock *sk; + struct list_head contid_list; }; /** @@ -311,6 +312,76 @@ static struct sock *audit_get_sk(const struct net *net) return aunet->sk; } +/** + * audit_get_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_contid_list(const struct net *net) +{ + struct audit_net *aunet = net_generic(net, audit_net_id); + + return &aunet->contid_list; +} + +void audit_contid_add(struct net *net, u64 contid) +{ + struct list_head *contid_list = audit_get_contid_list(net); + struct audit_contid *cont; + + if (!cid_valid(contid)) + return; + if (!list_empty(contid_list)) + list_for_each_entry(cont, contid_list, list) + if (cont->id == contid) { + refcount_inc(&cont->refcount); + return; + } + cont = kmalloc(sizeof(struct audit_contid), GFP_KERNEL); + if (!cont) + return; + INIT_LIST_HEAD(&cont->list); + cont->id = contid; + refcount_set(&cont->refcount, 1); + list_add(&cont->list, contid_list); +} + +void audit_contid_del(struct net *net, u64 contid) +{ + struct list_head *contid_list = audit_get_contid_list(net); + struct audit_contid *cont = NULL; + int found = 0; + + if (!cid_valid(contid)) + return; + if (!list_empty(contid_list)) + list_for_each_entry(cont, contid_list, list) + if (cont->id == contid) { + found = 1; + break; + } + if (!found) + return; + list_del(&cont->list); + if (refcount_dec_and_test(&cont->refcount)) + kfree(cont); +} + +void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p) +{ + u64 contid = audit_get_contid(p); + struct nsproxy *new = p->nsproxy; + + if (!cid_valid(contid)) + return; + audit_contid_del(ns->net_ns, contid); + if (new) + audit_contid_add(new->net_ns, contid); +} + void audit_panic(const char *message) { switch (audit_failure) { @@ -1550,6 +1621,7 @@ 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); return 0; } diff --git a/kernel/auditsc.c b/kernel/auditsc.c index ea1ee35..6ab5e5e 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; /* Can't set if audit disabled */ if (!task->audit) @@ -2185,10 +2187,13 @@ int audit_set_contid(struct task_struct *task, u64 contid) else if (cid_valid(oldcontid) && !task->audit->inherited) rc = -EEXIST; if (!rc) { + if (cid_valid(oldcontid)) + audit_contid_del(net, oldcontid); task_lock(task); task->audit->contid = contid; task->audit->inherited = false; task_unlock(task); + audit_contid_add(net, contid); } if (!audit_enabled) diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index f6c5d33..dcb69fe 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_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); -- 1.8.3.1 -- Linux-audit mailing list [email protected] https://www.redhat.com/mailman/listinfo/linux-audit
