[ghak90,(was,ghak32),V4,08/10] audit: add support for containerid to network namespaces

Submitted by Richard Guy Briggs on July 31, 2018, 8:07 p.m.

Details

Message ID 5a2b4aadf6994f622bc1ad27a8a6889c7e61edff.1533065887.git.rgb@redhat.com
State New
Series "audit: implement container identifier"
Headers show

Commit Message

Richard Guy Briggs July 31, 2018, 8:07 p.m.
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 <rgb@redhat.com>
---
 include/linux/audit.h | 17 ++++++++++
 kernel/audit.c        | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++
 kernel/auditsc.c      |  8 ++++-
 kernel/nsproxy.c      |  4 +++
 4 files changed, 114 insertions(+), 1 deletion(-)

Patch hide | download patch | download mbox

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 5580c25..9a02095 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);
@@ -159,6 +166,9 @@  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 void audit_netns_contid_add(struct net *net, u64 contid);
+extern void audit_netns_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);
 
@@ -212,6 +222,13 @@  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 void audit_netns_contid_add(struct net *net, u64 contid)
+{ }
+static inline void audit_netns_contid_del(struct net *net, u64 contid)
+{ }
+static inline void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p)
+{ }
+
 #define audit_enabled AUDIT_OFF
 #endif /* CONFIG_AUDIT */
 
diff --git a/kernel/audit.c b/kernel/audit.c
index fc9f026f..c5fed3b 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -100,9 +100,13 @@ 
 /**
  * struct audit_net - audit private network namespace data
  * @sk: communication socket
+ * @contid_list: audit container identifier list
+ * @contid_list_lock audit container identifier list lock
  */
 struct audit_net {
 	struct sock *sk;
+	struct list_head contid_list;
+	spinlock_t contid_list_lock;
 };
 
 /**
@@ -308,6 +312,86 @@  static struct sock *audit_get_sk(const struct net *net)
 	return aunet->sk;
 }
 
+/**
+ * audit_get_netns_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_netns_contid_list(const struct net *net)
+{
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	return &aunet->contid_list;
+}
+
+spinlock_t *audit_get_netns_contid_list_lock(const struct net *net)
+{
+	struct audit_net *aunet = net_generic(net, audit_net_id);
+
+	return &aunet->contid_list_lock;
+}
+
+void audit_netns_contid_add(struct net *net, u64 contid)
+{
+	spinlock_t *lock = audit_get_netns_contid_list_lock(net);
+	struct list_head *contid_list = audit_get_netns_contid_list(net);
+	struct audit_contid *cont;
+
+	if (!audit_contid_valid(contid))
+		return;
+	spin_lock(lock);
+	if (!list_empty(contid_list))
+		list_for_each_entry(cont, contid_list, list)
+			if (cont->id == contid) {
+				refcount_inc(&cont->refcount);
+				goto out;
+			}
+	cont = kmalloc(sizeof(struct audit_contid), GFP_KERNEL);
+	if (cont) {
+		INIT_LIST_HEAD(&cont->list);
+		cont->id = contid;
+		refcount_set(&cont->refcount, 1);
+		list_add(&cont->list, contid_list);
+	}
+out:
+	spin_unlock(lock);
+}
+
+void audit_netns_contid_del(struct net *net, u64 contid)
+{
+	spinlock_t *lock = audit_get_netns_contid_list_lock(net);
+	struct list_head *contid_list = audit_get_netns_contid_list(net);
+	struct audit_contid *cont = NULL;
+
+	if (!audit_contid_valid(contid))
+		return;
+	spin_lock(lock);
+	if (!list_empty(contid_list))
+		list_for_each_entry(cont, contid_list, list)
+			if (cont->id == contid) {
+				list_del(&cont->list);
+				if (refcount_dec_and_test(&cont->refcount))
+					kfree(cont);
+				break;
+			}
+	spin_unlock(lock);
+}
+
+void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p)
+{
+	u64 contid = audit_get_contid(p);
+	struct nsproxy *new = p->nsproxy;
+
+	if (!audit_contid_valid(contid))
+		return;
+	audit_netns_contid_del(ns->net_ns, contid);
+	if (new)
+		audit_netns_contid_add(new->net_ns, contid);
+}
+
 void audit_panic(const char *message)
 {
 	switch (audit_failure) {
@@ -1547,6 +1631,8 @@  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);
+	spin_lock_init(&aunet->contid_list_lock);
 
 	return 0;
 }
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 610c6869..fdf3f68 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;
 
 	task_lock(task);
 	/* Can't set if audit disabled */
@@ -2186,8 +2188,12 @@  int audit_set_contid(struct task_struct *task, u64 contid)
 	else if (!(thread_group_leader(task) && thread_group_empty(task)))
 		rc = -EALREADY;
 	read_unlock(&tasklist_lock);
-	if (!rc)
+	if (!rc) {
+		if (audit_contid_valid(oldcontid))
+			audit_netns_contid_del(net, oldcontid);
 		task->audit->contid = contid;
+		audit_netns_contid_add(net, contid);
+	}
 	task_unlock(task);
 
 	if (!audit_enabled)
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index f6c5d33..718b120 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_netns_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);

Comments

Paul Moore Oct. 19, 2018, 11:18 p.m.
On Tue, Jul 31, 2018 at 4:12 PM Richard Guy Briggs <rgb@redhat.com> 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 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 <rgb@redhat.com>
> ---
>  include/linux/audit.h | 17 ++++++++++
>  kernel/audit.c        | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/auditsc.c      |  8 ++++-
>  kernel/nsproxy.c      |  4 +++
>  4 files changed, 114 insertions(+), 1 deletion(-)

...

> @@ -308,6 +312,86 @@ static struct sock *audit_get_sk(const struct net *net)
>         return aunet->sk;
>  }
>
> +/**
> + * audit_get_netns_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_netns_contid_list(const struct net *net)
> +{
> +       struct audit_net *aunet = net_generic(net, audit_net_id);
> +
> +       return &aunet->contid_list;
> +}
> +
> +spinlock_t *audit_get_netns_contid_list_lock(const struct net *net)
> +{
> +       struct audit_net *aunet = net_generic(net, audit_net_id);
> +
> +       return &aunet->contid_list_lock;
> +}

Instead of returning the spinlock, just do away with the
audit_get_ns_contid_list_lock() function and create two separate lock
and unlock functions that basically do the net_generic() and spinlock
operations together, for example:

static int audit_netns_contid_lock(const struct net *net)
{
  aunet = net_generic(net, audit_net_id);

  if (!aunet)
    return -whatever;

  spin_lock(aunet->lock);
  return 0;
}

> +void audit_netns_contid_add(struct net *net, u64 contid)
> +{
> +       spinlock_t *lock = audit_get_netns_contid_list_lock(net);
> +       struct list_head *contid_list = audit_get_netns_contid_list(net);
> +       struct audit_contid *cont;
> +
> +       if (!audit_contid_valid(contid))
> +               return;
> +       spin_lock(lock);
> +       if (!list_empty(contid_list))
> +               list_for_each_entry(cont, contid_list, list)
> +                       if (cont->id == contid) {
> +                               refcount_inc(&cont->refcount);
> +                               goto out;
> +                       }
> +       cont = kmalloc(sizeof(struct audit_contid), GFP_KERNEL);
> +       if (cont) {
> +               INIT_LIST_HEAD(&cont->list);
> +               cont->id = contid;
> +               refcount_set(&cont->refcount, 1);
> +               list_add(&cont->list, contid_list);
> +       }
> +out:
> +       spin_unlock(lock);
> +}
> +
> +void audit_netns_contid_del(struct net *net, u64 contid)
> +{
> +       spinlock_t *lock = audit_get_netns_contid_list_lock(net);
> +       struct list_head *contid_list = audit_get_netns_contid_list(net);
> +       struct audit_contid *cont = NULL;
> +
> +       if (!audit_contid_valid(contid))
> +               return;
> +       spin_lock(lock);
> +       if (!list_empty(contid_list))
> +               list_for_each_entry(cont, contid_list, list)
> +                       if (cont->id == contid) {
> +                               list_del(&cont->list);
> +                               if (refcount_dec_and_test(&cont->refcount))
> +                                       kfree(cont);
> +                               break;
> +                       }
> +       spin_unlock(lock);
> +}
> +
> +void audit_switch_task_namespaces(struct nsproxy *ns, struct task_struct *p)
> +{
> +       u64 contid = audit_get_contid(p);
> +       struct nsproxy *new = p->nsproxy;
> +
> +       if (!audit_contid_valid(contid))
> +               return;
> +       audit_netns_contid_del(ns->net_ns, contid);
> +       if (new)
> +               audit_netns_contid_add(new->net_ns, contid);
> +}
> +
>  void audit_panic(const char *message)
>  {
>         switch (audit_failure) {
> @@ -1547,6 +1631,8 @@ 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);
> +       spin_lock_init(&aunet->contid_list_lock);
>
>         return 0;
>  }
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 610c6869..fdf3f68 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;
>
>         task_lock(task);
>         /* Can't set if audit disabled */
> @@ -2186,8 +2188,12 @@ int audit_set_contid(struct task_struct *task, u64 contid)
>         else if (!(thread_group_leader(task) && thread_group_empty(task)))
>                 rc = -EALREADY;
>         read_unlock(&tasklist_lock);
> -       if (!rc)
> +       if (!rc) {
> +               if (audit_contid_valid(oldcontid))
> +                       audit_netns_contid_del(net, oldcontid);
>                 task->audit->contid = contid;
> +               audit_netns_contid_add(net, contid);
> +       }
>         task_unlock(task);
>
>         if (!audit_enabled)
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index f6c5d33..718b120 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_netns_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);

--
paul moore
www.paul-moore.com