[PATCH ghak90 v11 08/11] audit: add support for containerid to network namespaces

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. Add the "record=" field to the A sample event: time->Thu Nov 26 10:24:47 2020 type=NETFILTER_PKT msg=audit(1606404287.984:174549): mark=0x15766399 saddr=127.0.0.1 daddr=127.0.0.1 proto=1 record=1 type=CONTAINER_ID msg=audit(1606404287.984:174549): record=1 contid=4112973747854606336,1916436506412318720 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; --- Acks removed due to redo rcu/spin locking: Acked-by: Neil Horman <nhorman(a)tuxdriver.com&gt; Reviewed-by: Ondrej Mosnacek <omosnace(a)redhat.com&gt; --- include/linux/audit.h | 17 +++ kernel/audit.c | 229 ++++++++++++++++++++++++++++++++++----- kernel/nsproxy.c | 4 + net/netfilter/nft_log.c | 14 ++- net/netfilter/xt_AUDIT.c | 14 ++- 5 files changed, 249 insertions(+), 29 deletions(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index 056a7c9a12a2..014f73296fec 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -217,6 +217,12 @@ extern int audit_get_contid_proc(char *tmpbuf, int TMPBUFLEN, extern int audit_set_contid(struct task_struct *tsk, u64 contid); +extern void audit_copy_namespaces(struct net *net, struct task_struct *tsk); +extern void audit_switch_task_namespaces(struct nsproxy *ns, + struct task_struct *p); +extern int audit_log_netns_contid_list(struct net *net, + struct audit_context *context); + extern u32 audit_enabled; extern int audit_signal_info(int sig, struct task_struct *t); @@ -281,6 +287,17 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) return AUDIT_SID_UNSET; } +static inline void audit_copy_namespaces(struct net *net, struct task_struct *tsk) +{ } +static inline void audit_switch_task_namespaces(struct nsproxy *ns, + struct task_struct *p) +{ } +static inline int audit_log_netns_contid_list(struct net *net, + struct audit_context *context) +{ + return 0; +} + #define audit_enabled AUDIT_OFF static inline int audit_signal_info(int sig, struct task_struct *t) diff --git a/kernel/audit.c b/kernel/audit.c index 533254167abf..c30bcd525dad 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 @@ static unsigned int audit_net_id; /** * struct audit_net - audit private network namespace data * @sk: communication socket + * @contobj_list: audit container identifier list + * @contobj_list_lock audit container identifier list lock */ struct audit_net { struct sock *sk; + struct list_head contobj_list; + spinlock_t contobj_list_lock; }; /** @@ -239,6 +244,16 @@ struct audit_task_info { static struct kmem_cache *audit_task_cache; +struct audit_contobj_netns { + struct list_head list; + struct audit_contobj *obj; + int count; + struct rcu_head rcu; +}; + +static void audit_netns_contid_add(struct net *net, struct audit_contobj *cont); +static void audit_netns_contid_del(struct net *net, struct audit_contobj *cont); + void __init audit_task_init(void) { audit_task_cache = kmem_cache_create("audit_task", @@ -373,11 +388,12 @@ void audit_contobj_put(void **cont, int count) { int i; struct audit_contobj **contobj = (struct audit_contobj **)cont; + unsigned long flags; - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); for (i = 0; i < count; i++) _audit_contobj_put(contobj[i]); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); } static inline int audit_hash_contid(u64 contid) @@ -453,11 +469,24 @@ int audit_alloc(struct task_struct *tsk) void audit_free(struct task_struct *tsk) { struct audit_task_info *info = tsk->audit; + unsigned long flags; + struct nsproxy *ns = tsk->nsproxy; + struct audit_contobj *cont; + rcu_read_lock(); + cont = _audit_contobj_get_bytask(tsk); + rcu_read_unlock(); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); + if (ns) { + audit_netns_contid_del(ns->net_ns, cont); + _audit_contobj_put(cont); + } + _audit_contobj_put(cont); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); audit_free_syscall(tsk); - spin_lock(&_audit_contobj_list_lock); - _audit_contobj_put(info->cont); - spin_unlock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); + _audit_contobj_put(cont); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); /* Freeing the audit_task_info struct must be performed after * audit_log_exit() due to need for loginuid and sessionid. */ @@ -465,9 +494,9 @@ void audit_free(struct task_struct *tsk) kmem_cache_free(audit_task_cache, info); rcu_read_lock(); if (audit_sig_adtsk == tsk) { - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put_sig(audit_sig_cid); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); audit_sig_cid = NULL; audit_sig_adtsk = NULL; } @@ -565,6 +594,145 @@ static struct sock *audit_get_sk(const struct net *net) return aunet->sk; } +void audit_netns_contid_add(struct net *net, struct audit_contobj *cont) +{ + struct audit_net *aunet; + struct list_head *contobj_list; + struct audit_contobj_netns *contns; + + if (!net) + return; + if (!cont) + return; + aunet = net_generic(net, audit_net_id); + if (!aunet) + return; + contobj_list = &aunet->contobj_list; + rcu_read_lock(); + spin_lock(&aunet->contobj_list_lock); + list_for_each_entry_rcu(contns, contobj_list, list) + if (contns->obj == cont) { + contns->count++; + goto out; + } + contns = kmalloc(sizeof(*contns), GFP_ATOMIC); + if (contns) { + INIT_LIST_HEAD(&contns->list); + contns->obj = cont; + contns->count = 1; + list_add_rcu(&contns->list, contobj_list); + } +out: + spin_unlock(&aunet->contobj_list_lock); + rcu_read_unlock(); +} + +void audit_netns_contid_del(struct net *net, struct audit_contobj *cont) +{ + struct audit_net *aunet; + struct list_head *contobj_list; + struct audit_contobj_netns *contns = NULL; + + if (!net) + return; + if (!cont) + return; + aunet = net_generic(net, audit_net_id); + if (!aunet) + return; + contobj_list = &aunet->contobj_list; + rcu_read_lock(); + spin_lock(&aunet->contobj_list_lock); + list_for_each_entry_rcu(contns, contobj_list, list) + if (contns->obj == cont) { + contns->count--; + if (contns->count < 1) { + list_del_rcu(&contns->list); + kfree_rcu(contns, rcu); + } + break; + } + spin_unlock(&aunet->contobj_list_lock); + rcu_read_unlock(); +} + +void audit_copy_namespaces(struct net *net, struct task_struct *tsk) +{ + struct audit_contobj *cont; + + rcu_read_lock(); + cont = _audit_contobj_get_bytask(tsk); + rcu_read_unlock(); + audit_netns_contid_add(net, cont); +} + +void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p) +{ + struct audit_contobj *cont; + struct nsproxy *new = p->nsproxy; + unsigned long flags; + + rcu_read_lock(); + cont = _audit_contobj_get_bytask(p); + rcu_read_unlock(); + if (!cont) + return; + audit_netns_contid_del(ns->net_ns, cont); + if (new) + audit_netns_contid_add(new->net_ns, cont); + else { + spin_lock_irqsave(&_audit_contobj_list_lock, flags); + _audit_contobj_put(cont); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); + } + spin_lock_irqsave(&_audit_contobj_list_lock, flags); + _audit_contobj_put(cont); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); +} + +/** + * audit_log_netns_contid_list - List contids for the given network namespace + * @net: the network namespace of interest + * @context: the audit context to use + * + * Returns 1 for record, 0 for none. + * + * Description: + * Issues a CONTAINER_ID record with a CSV list of contids associated + * with a network namespace to accompany a NETFILTER_PKT record. + */ +int audit_log_netns_contid_list(struct net *net, struct audit_context *context) +{ + struct audit_buffer *ab = NULL; + struct audit_contobj_netns *cont; + struct audit_net *aunet = net_generic(net, audit_net_id); + unsigned int record; + + if (!aunet) + return 0; + rcu_read_lock(); + list_for_each_entry_rcu(cont, &aunet->contobj_list, list) { + record = 1; + if (!ab) { + ab = audit_log_start(context, GFP_ATOMIC, + AUDIT_CONTAINER_ID); + if (!ab) { + audit_log_lost("out of memory in audit_log_netns_contid_list"); + goto out; + } + audit_log_format(ab, "record=1 contid=%llu", + cont->obj->id); + } else { + audit_log_format(ab, ",%llu", cont->obj->id); + } + } + audit_log_end(ab); +out: + rcu_read_unlock(); + return record; +} +EXPORT_SYMBOL(audit_log_netns_contid_list); + void audit_panic(const char *message) { switch (audit_failure) { @@ -1454,6 +1622,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) struct audit_sig_info2 *sig_data2; char *ctx = NULL; u32 len; + unsigned long flags; err = audit_netlink_ok(skb, msg_type); if (err) @@ -1727,9 +1896,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0, sig_data, sizeof(*sig_data) + len); kfree(sig_data); - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put_sig(audit_sig_cid); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); audit_sig_cid = NULL; break; case AUDIT_SIGNAL_INFO2: { @@ -1770,9 +1939,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) memcpy(sig_data2->data + contidstrlen, ctx, len); security_release_secctx(ctx, len); } - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put_sig(audit_sig_cid); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); audit_sig_cid = NULL; audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO2, 0, 0, sig_data2, sizeof(*sig_data2) + contidstrlen + len); @@ -1927,7 +2096,8 @@ static int __net_init audit_net_init(struct net *net) return -ENOMEM; } aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT; - + INIT_LIST_HEAD(&aunet->contobj_list); + spin_lock_init(&aunet->contobj_list_lock); return 0; } @@ -2476,6 +2646,7 @@ int audit_log_container_id_ctx(struct audit_context *context) { struct audit_contobj *contobj; int record; + unsigned long flags; rcu_read_lock(); contobj = _audit_contobj_get_bytask(current); @@ -2483,9 +2654,9 @@ int audit_log_container_id_ctx(struct audit_context *context) if (!contobj) return 0; record = _audit_log_container_id(context, contobj); - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put(contobj); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); return record; } @@ -2732,6 +2903,7 @@ int audit_signal_info(int sig, struct task_struct *t) (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2)) { kuid_t uid = current_uid(), auid; + unsigned long flags; audit_sig_pid = task_tgid_nr(current); auid = audit_get_loginuid(current); @@ -2740,9 +2912,9 @@ int audit_signal_info(int sig, struct task_struct *t) else audit_sig_uid = uid; security_task_getsecid(current, &audit_sig_sid); - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put_sig(audit_sig_cid); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); rcu_read_lock(); audit_sig_cid = _audit_contobj_get_sig_bytask(current); rcu_read_unlock(); @@ -2772,6 +2944,8 @@ int audit_set_contid(struct task_struct *tsk, u64 contid) struct audit_contobj *cont = NULL, *newcont = NULL; int h; struct audit_task_info *info = tsk->audit; + unsigned long flags; + struct net *net = tsk->nsproxy->net_ns; /* Can't set if audit disabled */ if (!info) { @@ -2800,21 +2974,21 @@ int audit_set_contid(struct task_struct *tsk, u64 contid) goto error; h = audit_hash_contid(contid); - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); list_for_each_entry_rcu(cont, &audit_contid_hash[h], list) if (cont->id == contid) { /* task injection to existing container */ if (current == cont->owner) { if (!refcount_read(&cont->refcount)) { rc = -ENOTUNIQ; - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); goto error; } _audit_contobj_get(cont); newcont = cont; } else { rc = -ENOTUNIQ; - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); goto error; } break; @@ -2830,13 +3004,17 @@ int audit_set_contid(struct task_struct *tsk, u64 contid) &audit_contid_hash[h]); } else { rc = -ENOMEM; - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); goto error; } } info->cont = newcont; _audit_contobj_put(oldcont); - spin_unlock(&_audit_contobj_list_lock); + audit_netns_contid_del(net, oldcont); + _audit_contobj_put(oldcont); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); + _audit_contobj_get(newcont); + audit_netns_contid_add(net, newcont); error: rcu_read_unlock(); task_unlock(tsk); @@ -2852,9 +3030,9 @@ int audit_set_contid(struct task_struct *tsk, u64 contid) audit_log_format(ab, "op=set opid=%d contid=%llu old-contid=%llu", task_tgid_nr(tsk), contid, oldcont ? oldcont->id : -1); - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put(oldcont); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); audit_log_end(ab); return rc; } @@ -2878,6 +3056,7 @@ void audit_log_container_drop(void) { struct audit_buffer *ab; struct audit_contobj *cont; + unsigned long flags; rcu_read_lock(); cont = _audit_contobj_get_bytask(current); @@ -2893,9 +3072,9 @@ void audit_log_container_drop(void) task_tgid_nr(current), cont->id); audit_log_end(ab); out: - spin_lock(&_audit_contobj_list_lock); + spin_lock_irqsave(&_audit_contobj_list_lock, flags); _audit_contobj_put(cont); - spin_unlock(&_audit_contobj_list_lock); + spin_unlock_irqrestore(&_audit_contobj_list_lock, flags); } /** diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index abc01fcad8c7..352bddea6e6f 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -26,6 +26,7 @@ #include <linux/syscalls.h> #include <linux/cgroup.h> #include <linux/perf_event.h> +#include <linux/audit.h> static struct kmem_cache *nsproxy_cachep; @@ -182,6 +183,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk) timens_on_fork(new_ns, tsk); tsk->nsproxy = new_ns; + if (flags & CLONE_NEWNET) + audit_copy_namespaces(new_ns->net_ns, tsk); return 0; } @@ -244,6 +247,7 @@ 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) put_nsproxy(ns); diff --git a/net/netfilter/nft_log.c b/net/netfilter/nft_log.c index a06a46b039c5..f433c93c80e1 100644 --- a/net/netfilter/nft_log.c +++ b/net/netfilter/nft_log.c @@ -66,13 +66,19 @@ static void nft_log_eval_audit(const struct nft_pktinfo *pkt) struct sk_buff *skb = pkt->skb; struct audit_buffer *ab; int fam = -1; + struct audit_context *context; + struct net *net; + int record; if (!audit_enabled) return; - ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT); + context = audit_alloc_local(GFP_ATOMIC); + net = xt_net(&pkt->xt); + record = audit_log_netns_contid_list(net, context); + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_NETFILTER_PKT); if (!ab) - return; + goto errout; audit_log_format(ab, "mark=%#x", skb->mark); @@ -98,7 +104,11 @@ static void nft_log_eval_audit(const struct nft_pktinfo *pkt) if (fam == -1) audit_log_format(ab, " saddr=? daddr=? proto=-1"); + if (record) + audit_log_format(ab, " record=%d", record); audit_log_end(ab); +errout: + audit_free_context(context); } static void nft_log_eval(const struct nft_expr *expr, diff --git a/net/netfilter/xt_AUDIT.c b/net/netfilter/xt_AUDIT.c index 9cdc16b0d0d8..d2c5069745ea 100644 --- a/net/netfilter/xt_AUDIT.c +++ b/net/netfilter/xt_AUDIT.c @@ -68,10 +68,16 @@ audit_tg(struct sk_buff *skb, const struct xt_action_param *par) { struct audit_buffer *ab; int fam = -1; + struct audit_context *context; + struct net *net; + int record; if (audit_enabled == AUDIT_OFF) - goto errout; - ab = audit_log_start(NULL, GFP_ATOMIC, AUDIT_NETFILTER_PKT); + goto out; + context = audit_alloc_local(GFP_ATOMIC); + net = xt_net(par); + record = audit_log_netns_contid_list(net, context); + ab = audit_log_start(context, GFP_ATOMIC, AUDIT_NETFILTER_PKT); if (ab == NULL) goto errout; @@ -99,9 +105,13 @@ audit_tg(struct sk_buff *skb, const struct xt_action_param *par) if (fam == -1) audit_log_format(ab, " saddr=? daddr=? proto=-1"); + if (record) + audit_log_format(ab, " record=%d", record); audit_log_end(ab); errout: + audit_free_context(context); +out: return XT_CONTINUE; } -- 2.18.4