[PATCH 08/22] Audit: make kauditd_task per user namespace
From: Gao feng
Date: Tue Jun 18 2013 - 21:53:42 EST
This patch makes kauditd_task per user namespace,
Since right now we only allow user in init user
namesapce to send audit netlink message to kernel,
so actually the kauditd_task belongs to other user
namespace will still not run.
Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
---
include/linux/audit.h | 1 +
include/linux/user_namespace.h | 15 +++++++++--
kernel/audit.c | 58 ++++++++++++++++++++++++++----------------
kernel/audit.h | 5 ++--
kernel/auditsc.c | 6 ++---
5 files changed, 55 insertions(+), 30 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 6720901..179351d 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/user_namespace.h>
struct audit_sig_info {
uid_t uid;
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 53420a4..ae69f20 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -21,8 +21,10 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */
#ifdef CONFIG_AUDIT
struct audit_ctrl {
struct sock *sock;
+ int pid;
struct sk_buff_head queue;
struct sk_buff_head hold_queue;
+ struct task_struct *kauditd_task;
};
#endif
@@ -59,8 +61,17 @@ extern void free_user_ns(struct user_namespace *ns);
static inline void put_user_ns(struct user_namespace *ns)
{
- if (ns && atomic_dec_and_test(&ns->count))
- free_user_ns(ns);
+ if (ns) {
+ if (atomic_dec_and_test(&ns->count)) {
+ free_user_ns(ns);
+ } else if (atomic_read(&ns->count) == 1) {
+ /* If the last user of this userns is kauditd,
+ * we should wake up the kauditd and let it kill
+ * itself, Then this userns will be destroyed.*/
+ if (ns->audit.kauditd_task)
+ wake_up_process(ns->audit.kauditd_task);
+ }
+ }
}
struct seq_operations;
diff --git a/kernel/audit.c b/kernel/audit.c
index 75325f0..7b696cd5 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -94,7 +94,6 @@ static int audit_failure = AUDIT_FAIL_PRINTK;
* contains the pid of the auditd process and audit_nlk_portid contains
* the portid to use to send netlink messages to that process.
*/
-int audit_pid;
static int audit_nlk_portid;
/* If audit_rate_limit is non-zero, limit the rate of sending audit records
@@ -131,7 +130,6 @@ static DEFINE_SPINLOCK(audit_freelist_lock);
static int audit_freelist_count;
static LIST_HEAD(audit_freelist);
-static struct task_struct *kauditd_task;
static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
@@ -184,7 +182,7 @@ void audit_panic(const char *message)
break;
case AUDIT_FAIL_PANIC:
/* test audit_pid since printk is always losey, why bother? */
- if (audit_pid)
+ if (&init_user_ns.audit.pid)
panic("audit: %s\n", message);
break;
}
@@ -386,9 +384,10 @@ static void kauditd_send_skb(struct sk_buff *skb)
audit_nlk_portid, 0);
if (err < 0) {
BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */
- printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
+ printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n",
+ init_user_ns.audit.pid);
audit_log_lost("auditd disappeared\n");
- audit_pid = 0;
+ init_user_ns.audit.pid = 0;
/* we might get lucky and get this in the next auditd */
audit_hold_skb(skb);
} else
@@ -411,19 +410,19 @@ static void kauditd_send_skb(struct sk_buff *skb)
* in 5 years when I want to play with this again I'll see this
* note and still have no friggin idea what i'm thinking today.
*/
-static void flush_hold_queue(void)
+static void flush_hold_queue(struct user_namespace *ns)
{
struct sk_buff *skb;
- struct sk_buff_head *hold_queue = &init_user_ns.audit.hold_queue;
+ struct sk_buff_head *hold_queue = &ns->audit.hold_queue;
- if (!audit_default || !audit_pid || !init_user_ns.audit.sock)
+ if (!audit_default || !ns->audit.pid || !ns->audit.sock)
return;
skb = skb_dequeue(hold_queue);
if (likely(!skb))
return;
- while (skb && audit_pid) {
+ while (skb && ns->audit.pid) {
kauditd_send_skb(skb);
skb = skb_dequeue(hold_queue);
}
@@ -438,18 +437,26 @@ static void flush_hold_queue(void)
static int kauditd_thread(void *dummy)
{
+ struct user_namespace *ns = dummy;
+
set_freezable();
while (!kthread_should_stop()) {
struct sk_buff *skb;
- struct sk_buff_head *queue = &init_user_ns.audit.queue;
+ struct sk_buff_head *queue = &ns->audit.queue;
DECLARE_WAITQUEUE(wait, current);
- flush_hold_queue();
+ /* Ok, We are the last user of this userns,
+ * It's time to go. Kill kauditd thread and
+ * release the userns. */
+ if (atomic_read(&ns->count) == 1)
+ break;
+
+ flush_hold_queue(ns);
skb = skb_dequeue(queue);
wake_up(&audit_backlog_wait);
if (skb) {
- if (audit_pid && init_user_ns.audit.sock)
+ if (ns->audit.pid && ns->audit.sock)
kauditd_send_skb(skb);
else
audit_printk_skb(skb);
@@ -466,6 +473,8 @@ static int kauditd_thread(void *dummy)
__set_current_state(TASK_RUNNING);
remove_wait_queue(&kauditd_wait, &wait);
}
+
+ put_user_ns(ns);
return 0;
}
@@ -658,13 +667,17 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
ns = current_user_ns();
/* As soon as there's any sign of userspace auditd,
* start kauditd to talk to it */
- if (!kauditd_task) {
- kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
- if (IS_ERR(kauditd_task)) {
- err = PTR_ERR(kauditd_task);
- kauditd_task = NULL;
- return err;
+ if (!ns->audit.kauditd_task) {
+ struct task_struct *tsk;
+
+ tsk = kthread_run(kauditd_thread,
+ get_user_ns(ns), "kauditd");
+ if (IS_ERR(tsk)) {
+ put_user_ns(ns);
+ return PTR_ERR(tsk);
}
+
+ ns->audit.kauditd_task = tsk;
}
seq = nlh->nlmsg_seq;
data = nlmsg_data(nlh);
@@ -673,7 +686,7 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
case AUDIT_GET:
status_set.enabled = audit_enabled;
status_set.failure = audit_failure;
- status_set.pid = audit_pid;
+ status_set.pid = ns->audit.pid;
status_set.rate_limit = audit_rate_limit;
status_set.backlog_limit = audit_backlog_limit;
status_set.lost = atomic_read(&audit_lost);
@@ -700,8 +713,9 @@ static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
int new_pid = status_get->pid;
if (audit_enabled != AUDIT_OFF)
- audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
- audit_pid = new_pid;
+ audit_log_config_change("audit_pid", new_pid,
+ ns->audit.pid, 1);
+ ns->audit.pid = new_pid;
audit_nlk_portid = NETLINK_CB(skb).portid;
}
if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
@@ -1714,7 +1728,7 @@ void audit_log_end(struct audit_buffer *ab)
struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
- if (audit_pid && init_user_ns.audit.sock) {
+ if (init_user_ns.audit.pid && init_user_ns.audit.sock) {
skb_queue_tail(&init_user_ns.audit.queue, ab->skb);
wake_up_interruptible(&kauditd_wait);
} else {
diff --git a/kernel/audit.h b/kernel/audit.h
index 2258827..d746214 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -217,8 +217,6 @@ extern void audit_log_name(struct audit_context *context,
struct audit_names *n, struct path *path,
int record_num, int *call_panic);
-extern int audit_pid;
-
#define AUDIT_INODE_BUCKETS 32
extern struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
@@ -309,7 +307,8 @@ extern u32 audit_sig_sid;
extern int __audit_signal_info(int sig, struct task_struct *t);
static inline int audit_signal_info(int sig, struct task_struct *t)
{
- if (unlikely((audit_pid && t->tgid == audit_pid) ||
+ if (unlikely((init_user_ns.audit.pid &&
+ t->tgid == init_user_ns.audit.pid) ||
(audit_signals && !audit_dummy_context())))
return __audit_signal_info(sig, t);
return 0;
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3c8a601..8ba8684 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -745,7 +745,7 @@ static enum audit_state audit_filter_syscall(struct task_struct *tsk,
struct audit_entry *e;
enum audit_state state;
- if (audit_pid && tsk->tgid == audit_pid)
+ if (init_user_ns.audit.pid && tsk->tgid == init_user_ns.audit.pid)
return AUDIT_DISABLED;
rcu_read_lock();
@@ -806,7 +806,7 @@ void audit_filter_inodes(struct task_struct *tsk, struct audit_context *ctx)
{
struct audit_names *n;
- if (audit_pid && tsk->tgid == audit_pid)
+ if (init_user_ns.audit.pid && tsk->tgid == init_user_ns.audit.pid)
return;
rcu_read_lock();
@@ -2220,7 +2220,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
struct audit_context *ctx = tsk->audit_context;
kuid_t uid = current_uid(), t_uid = task_uid(t);
- if (audit_pid && t->tgid == audit_pid) {
+ if (init_user_ns.audit.pid && t->tgid == init_user_ns.audit.pid) {
if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2) {
audit_sig_pid = tsk->pid;
if (uid_valid(tsk->loginuid))
--
1.8.1.4
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