![Yejune Deng](/assets/img/avatar_default.png)
atomic_inc_return() is a little neater Signed-off-by: Yejune Deng <yejune.deng@gmail.com> Signed-off-by: Paul Moore <paul@paul-moore.com>
2428 lines
64 KiB
C
2428 lines
64 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* audit.c -- Auditing support
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* Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
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* System-call specific features have moved to auditsc.c
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*
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* Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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*
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* Written by Rickard E. (Rik) Faith <faith@redhat.com>
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*
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* Goals: 1) Integrate fully with Security Modules.
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* 2) Minimal run-time overhead:
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* a) Minimal when syscall auditing is disabled (audit_enable=0).
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* b) Small when syscall auditing is enabled and no audit record
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* is generated (defer as much work as possible to record
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* generation time):
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* i) context is allocated,
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* ii) names from getname are stored without a copy, and
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* iii) inode information stored from path_lookup.
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* 3) Ability to disable syscall auditing at boot time (audit=0).
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* 4) Usable by other parts of the kernel (if audit_log* is called,
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* then a syscall record will be generated automatically for the
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* current syscall).
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* 5) Netlink interface to user-space.
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* 6) Support low-overhead kernel-based filtering to minimize the
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* information that must be passed to user-space.
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*
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* Audit userspace, documentation, tests, and bug/issue trackers:
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* https://github.com/linux-audit
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/file.h>
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#include <linux/init.h>
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#include <linux/types.h>
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#include <linux/atomic.h>
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#include <linux/mm.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/err.h>
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#include <linux/kthread.h>
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#include <linux/kernel.h>
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#include <linux/syscalls.h>
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#include <linux/spinlock.h>
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#include <linux/rcupdate.h>
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#include <linux/mutex.h>
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#include <linux/gfp.h>
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#include <linux/pid.h>
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#include <linux/audit.h>
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#include <net/sock.h>
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#include <net/netlink.h>
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#include <linux/skbuff.h>
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#ifdef CONFIG_SECURITY
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#include <linux/security.h>
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#endif
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#include <linux/freezer.h>
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#include <linux/pid_namespace.h>
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#include <net/netns/generic.h>
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#include "audit.h"
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/* No auditing will take place until audit_initialized == AUDIT_INITIALIZED.
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* (Initialization happens after skb_init is called.) */
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#define AUDIT_DISABLED -1
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#define AUDIT_UNINITIALIZED 0
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#define AUDIT_INITIALIZED 1
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static int audit_initialized = AUDIT_UNINITIALIZED;
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u32 audit_enabled = AUDIT_OFF;
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bool audit_ever_enabled = !!AUDIT_OFF;
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EXPORT_SYMBOL_GPL(audit_enabled);
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/* Default state when kernel boots without any parameters. */
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static u32 audit_default = AUDIT_OFF;
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/* If auditing cannot proceed, audit_failure selects what happens. */
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static u32 audit_failure = AUDIT_FAIL_PRINTK;
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/* private audit network namespace index */
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static unsigned int audit_net_id;
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/**
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* struct audit_net - audit private network namespace data
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* @sk: communication socket
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*/
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struct audit_net {
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struct sock *sk;
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};
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/**
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* struct auditd_connection - kernel/auditd connection state
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* @pid: auditd PID
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* @portid: netlink portid
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* @net: the associated network namespace
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* @rcu: RCU head
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*
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* Description:
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* This struct is RCU protected; you must either hold the RCU lock for reading
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* or the associated spinlock for writing.
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*/
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struct auditd_connection {
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struct pid *pid;
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u32 portid;
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struct net *net;
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struct rcu_head rcu;
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};
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static struct auditd_connection __rcu *auditd_conn;
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static DEFINE_SPINLOCK(auditd_conn_lock);
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/* If audit_rate_limit is non-zero, limit the rate of sending audit records
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* to that number per second. This prevents DoS attacks, but results in
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* audit records being dropped. */
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static u32 audit_rate_limit;
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/* Number of outstanding audit_buffers allowed.
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* When set to zero, this means unlimited. */
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static u32 audit_backlog_limit = 64;
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#define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
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static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
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/* The identity of the user shutting down the audit system. */
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static kuid_t audit_sig_uid = INVALID_UID;
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static pid_t audit_sig_pid = -1;
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static u32 audit_sig_sid;
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/* Records can be lost in several ways:
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0) [suppressed in audit_alloc]
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1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
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2) out of memory in audit_log_move [alloc_skb]
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3) suppressed due to audit_rate_limit
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4) suppressed due to audit_backlog_limit
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*/
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static atomic_t audit_lost = ATOMIC_INIT(0);
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/* Monotonically increasing sum of time the kernel has spent
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* waiting while the backlog limit is exceeded.
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*/
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static atomic_t audit_backlog_wait_time_actual = ATOMIC_INIT(0);
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/* Hash for inode-based rules */
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struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
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static struct kmem_cache *audit_buffer_cache;
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/* queue msgs to send via kauditd_task */
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static struct sk_buff_head audit_queue;
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/* queue msgs due to temporary unicast send problems */
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static struct sk_buff_head audit_retry_queue;
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/* queue msgs waiting for new auditd connection */
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static struct sk_buff_head audit_hold_queue;
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/* queue servicing thread */
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static struct task_struct *kauditd_task;
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static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
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/* waitqueue for callers who are blocked on the audit backlog */
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static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
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static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
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.mask = -1,
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.features = 0,
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.lock = 0,};
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static char *audit_feature_names[2] = {
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"only_unset_loginuid",
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"loginuid_immutable",
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};
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/**
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* struct audit_ctl_mutex - serialize requests from userspace
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* @lock: the mutex used for locking
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* @owner: the task which owns the lock
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*
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* Description:
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* This is the lock struct used to ensure we only process userspace requests
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* in an orderly fashion. We can't simply use a mutex/lock here because we
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* need to track lock ownership so we don't end up blocking the lock owner in
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* audit_log_start() or similar.
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*/
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static struct audit_ctl_mutex {
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struct mutex lock;
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void *owner;
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} audit_cmd_mutex;
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/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
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* audit records. Since printk uses a 1024 byte buffer, this buffer
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* should be at least that large. */
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#define AUDIT_BUFSIZ 1024
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/* The audit_buffer is used when formatting an audit record. The caller
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* locks briefly to get the record off the freelist or to allocate the
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* buffer, and locks briefly to send the buffer to the netlink layer or
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* to place it on a transmit queue. Multiple audit_buffers can be in
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* use simultaneously. */
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struct audit_buffer {
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struct sk_buff *skb; /* formatted skb ready to send */
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struct audit_context *ctx; /* NULL or associated context */
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gfp_t gfp_mask;
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};
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struct audit_reply {
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__u32 portid;
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struct net *net;
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struct sk_buff *skb;
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};
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/**
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* auditd_test_task - Check to see if a given task is an audit daemon
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* @task: the task to check
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*
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* Description:
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* Return 1 if the task is a registered audit daemon, 0 otherwise.
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*/
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int auditd_test_task(struct task_struct *task)
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{
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int rc;
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struct auditd_connection *ac;
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rcu_read_lock();
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ac = rcu_dereference(auditd_conn);
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rc = (ac && ac->pid == task_tgid(task) ? 1 : 0);
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rcu_read_unlock();
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return rc;
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}
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/**
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* audit_ctl_lock - Take the audit control lock
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*/
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void audit_ctl_lock(void)
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{
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mutex_lock(&audit_cmd_mutex.lock);
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audit_cmd_mutex.owner = current;
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}
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/**
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* audit_ctl_unlock - Drop the audit control lock
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*/
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void audit_ctl_unlock(void)
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{
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audit_cmd_mutex.owner = NULL;
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mutex_unlock(&audit_cmd_mutex.lock);
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}
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/**
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* audit_ctl_owner_current - Test to see if the current task owns the lock
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*
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* Description:
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* Return true if the current task owns the audit control lock, false if it
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* doesn't own the lock.
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*/
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static bool audit_ctl_owner_current(void)
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{
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return (current == audit_cmd_mutex.owner);
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}
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/**
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* auditd_pid_vnr - Return the auditd PID relative to the namespace
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*
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* Description:
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* Returns the PID in relation to the namespace, 0 on failure.
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*/
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static pid_t auditd_pid_vnr(void)
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{
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pid_t pid;
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const struct auditd_connection *ac;
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rcu_read_lock();
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ac = rcu_dereference(auditd_conn);
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if (!ac || !ac->pid)
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pid = 0;
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else
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pid = pid_vnr(ac->pid);
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rcu_read_unlock();
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return pid;
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}
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/**
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* audit_get_sk - Return the audit socket for the given network namespace
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* @net: the destination network namespace
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*
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* Description:
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* Returns the sock pointer if valid, NULL otherwise. The caller must ensure
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* that a reference is held for the network namespace while the sock is in use.
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*/
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static struct sock *audit_get_sk(const struct net *net)
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{
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struct audit_net *aunet;
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if (!net)
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return NULL;
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aunet = net_generic(net, audit_net_id);
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return aunet->sk;
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}
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void audit_panic(const char *message)
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{
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switch (audit_failure) {
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case AUDIT_FAIL_SILENT:
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break;
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case AUDIT_FAIL_PRINTK:
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if (printk_ratelimit())
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pr_err("%s\n", message);
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break;
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case AUDIT_FAIL_PANIC:
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panic("audit: %s\n", message);
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break;
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}
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}
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static inline int audit_rate_check(void)
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{
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static unsigned long last_check = 0;
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static int messages = 0;
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static DEFINE_SPINLOCK(lock);
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unsigned long flags;
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unsigned long now;
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unsigned long elapsed;
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int retval = 0;
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if (!audit_rate_limit) return 1;
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spin_lock_irqsave(&lock, flags);
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if (++messages < audit_rate_limit) {
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retval = 1;
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} else {
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now = jiffies;
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elapsed = now - last_check;
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if (elapsed > HZ) {
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last_check = now;
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messages = 0;
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retval = 1;
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}
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}
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spin_unlock_irqrestore(&lock, flags);
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return retval;
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}
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/**
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* audit_log_lost - conditionally log lost audit message event
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* @message: the message stating reason for lost audit message
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*
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* Emit at least 1 message per second, even if audit_rate_check is
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* throttling.
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* Always increment the lost messages counter.
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*/
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void audit_log_lost(const char *message)
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{
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static unsigned long last_msg = 0;
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static DEFINE_SPINLOCK(lock);
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unsigned long flags;
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unsigned long now;
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int print;
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atomic_inc(&audit_lost);
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print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
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if (!print) {
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spin_lock_irqsave(&lock, flags);
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now = jiffies;
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if (now - last_msg > HZ) {
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print = 1;
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last_msg = now;
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}
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spin_unlock_irqrestore(&lock, flags);
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}
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if (print) {
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if (printk_ratelimit())
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pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
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atomic_read(&audit_lost),
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audit_rate_limit,
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audit_backlog_limit);
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audit_panic(message);
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}
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}
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static int audit_log_config_change(char *function_name, u32 new, u32 old,
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int allow_changes)
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{
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struct audit_buffer *ab;
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int rc = 0;
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ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE);
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if (unlikely(!ab))
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return rc;
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audit_log_format(ab, "op=set %s=%u old=%u ", function_name, new, old);
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audit_log_session_info(ab);
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rc = audit_log_task_context(ab);
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if (rc)
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allow_changes = 0; /* Something weird, deny request */
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audit_log_format(ab, " res=%d", allow_changes);
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audit_log_end(ab);
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return rc;
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}
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static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
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{
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int allow_changes, rc = 0;
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u32 old = *to_change;
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/* check if we are locked */
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if (audit_enabled == AUDIT_LOCKED)
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allow_changes = 0;
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else
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allow_changes = 1;
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if (audit_enabled != AUDIT_OFF) {
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rc = audit_log_config_change(function_name, new, old, allow_changes);
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if (rc)
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allow_changes = 0;
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}
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/* If we are allowed, make the change */
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if (allow_changes == 1)
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*to_change = new;
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/* Not allowed, update reason */
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else if (rc == 0)
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rc = -EPERM;
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return rc;
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}
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static int audit_set_rate_limit(u32 limit)
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{
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return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
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}
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static int audit_set_backlog_limit(u32 limit)
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{
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return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
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}
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static int audit_set_backlog_wait_time(u32 timeout)
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{
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return audit_do_config_change("audit_backlog_wait_time",
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&audit_backlog_wait_time, timeout);
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}
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static int audit_set_enabled(u32 state)
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{
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int rc;
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if (state > AUDIT_LOCKED)
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return -EINVAL;
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rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
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if (!rc)
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audit_ever_enabled |= !!state;
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return rc;
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}
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static int audit_set_failure(u32 state)
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{
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if (state != AUDIT_FAIL_SILENT
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&& state != AUDIT_FAIL_PRINTK
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&& state != AUDIT_FAIL_PANIC)
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return -EINVAL;
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return audit_do_config_change("audit_failure", &audit_failure, state);
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}
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/**
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* auditd_conn_free - RCU helper to release an auditd connection struct
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* @rcu: RCU head
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*
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* Description:
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* Drop any references inside the auditd connection tracking struct and free
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* the memory.
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*/
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static void auditd_conn_free(struct rcu_head *rcu)
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{
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struct auditd_connection *ac;
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ac = container_of(rcu, struct auditd_connection, rcu);
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put_pid(ac->pid);
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put_net(ac->net);
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kfree(ac);
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}
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/**
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* auditd_set - Set/Reset the auditd connection state
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* @pid: auditd PID
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* @portid: auditd netlink portid
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* @net: auditd network namespace pointer
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*
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* Description:
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* This function will obtain and drop network namespace references as
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* necessary. Returns zero on success, negative values on failure.
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*/
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static int auditd_set(struct pid *pid, u32 portid, struct net *net)
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{
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unsigned long flags;
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struct auditd_connection *ac_old, *ac_new;
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if (!pid || !net)
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return -EINVAL;
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ac_new = kzalloc(sizeof(*ac_new), GFP_KERNEL);
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if (!ac_new)
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return -ENOMEM;
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ac_new->pid = get_pid(pid);
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ac_new->portid = portid;
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ac_new->net = get_net(net);
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spin_lock_irqsave(&auditd_conn_lock, flags);
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ac_old = rcu_dereference_protected(auditd_conn,
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lockdep_is_held(&auditd_conn_lock));
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rcu_assign_pointer(auditd_conn, ac_new);
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spin_unlock_irqrestore(&auditd_conn_lock, flags);
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if (ac_old)
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call_rcu(&ac_old->rcu, auditd_conn_free);
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return 0;
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}
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/**
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* kauditd_printk_skb - Print the audit record to the ring buffer
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* @skb: audit record
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*
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|
* Whatever the reason, this packet may not make it to the auditd connection
|
|
* so write it via printk so the information isn't completely lost.
|
|
*/
|
|
static void kauditd_printk_skb(struct sk_buff *skb)
|
|
{
|
|
struct nlmsghdr *nlh = nlmsg_hdr(skb);
|
|
char *data = nlmsg_data(nlh);
|
|
|
|
if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit())
|
|
pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
|
|
}
|
|
|
|
/**
|
|
* kauditd_rehold_skb - Handle a audit record send failure in the hold queue
|
|
* @skb: audit record
|
|
*
|
|
* Description:
|
|
* This should only be used by the kauditd_thread when it fails to flush the
|
|
* hold queue.
|
|
*/
|
|
static void kauditd_rehold_skb(struct sk_buff *skb)
|
|
{
|
|
/* put the record back in the queue at the same place */
|
|
skb_queue_head(&audit_hold_queue, skb);
|
|
}
|
|
|
|
/**
|
|
* kauditd_hold_skb - Queue an audit record, waiting for auditd
|
|
* @skb: audit record
|
|
*
|
|
* Description:
|
|
* Queue the audit record, waiting for an instance of auditd. When this
|
|
* function is called we haven't given up yet on sending the record, but things
|
|
* are not looking good. The first thing we want to do is try to write the
|
|
* record via printk and then see if we want to try and hold on to the record
|
|
* and queue it, if we have room. If we want to hold on to the record, but we
|
|
* don't have room, record a record lost message.
|
|
*/
|
|
static void kauditd_hold_skb(struct sk_buff *skb)
|
|
{
|
|
/* at this point it is uncertain if we will ever send this to auditd so
|
|
* try to send the message via printk before we go any further */
|
|
kauditd_printk_skb(skb);
|
|
|
|
/* can we just silently drop the message? */
|
|
if (!audit_default) {
|
|
kfree_skb(skb);
|
|
return;
|
|
}
|
|
|
|
/* if we have room, queue the message */
|
|
if (!audit_backlog_limit ||
|
|
skb_queue_len(&audit_hold_queue) < audit_backlog_limit) {
|
|
skb_queue_tail(&audit_hold_queue, skb);
|
|
return;
|
|
}
|
|
|
|
/* we have no other options - drop the message */
|
|
audit_log_lost("kauditd hold queue overflow");
|
|
kfree_skb(skb);
|
|
}
|
|
|
|
/**
|
|
* kauditd_retry_skb - Queue an audit record, attempt to send again to auditd
|
|
* @skb: audit record
|
|
*
|
|
* Description:
|
|
* Not as serious as kauditd_hold_skb() as we still have a connected auditd,
|
|
* but for some reason we are having problems sending it audit records so
|
|
* queue the given record and attempt to resend.
|
|
*/
|
|
static void kauditd_retry_skb(struct sk_buff *skb)
|
|
{
|
|
/* NOTE: because records should only live in the retry queue for a
|
|
* short period of time, before either being sent or moved to the hold
|
|
* queue, we don't currently enforce a limit on this queue */
|
|
skb_queue_tail(&audit_retry_queue, skb);
|
|
}
|
|
|
|
/**
|
|
* auditd_reset - Disconnect the auditd connection
|
|
* @ac: auditd connection state
|
|
*
|
|
* Description:
|
|
* Break the auditd/kauditd connection and move all the queued records into the
|
|
* hold queue in case auditd reconnects. It is important to note that the @ac
|
|
* pointer should never be dereferenced inside this function as it may be NULL
|
|
* or invalid, you can only compare the memory address! If @ac is NULL then
|
|
* the connection will always be reset.
|
|
*/
|
|
static void auditd_reset(const struct auditd_connection *ac)
|
|
{
|
|
unsigned long flags;
|
|
struct sk_buff *skb;
|
|
struct auditd_connection *ac_old;
|
|
|
|
/* if it isn't already broken, break the connection */
|
|
spin_lock_irqsave(&auditd_conn_lock, flags);
|
|
ac_old = rcu_dereference_protected(auditd_conn,
|
|
lockdep_is_held(&auditd_conn_lock));
|
|
if (ac && ac != ac_old) {
|
|
/* someone already registered a new auditd connection */
|
|
spin_unlock_irqrestore(&auditd_conn_lock, flags);
|
|
return;
|
|
}
|
|
rcu_assign_pointer(auditd_conn, NULL);
|
|
spin_unlock_irqrestore(&auditd_conn_lock, flags);
|
|
|
|
if (ac_old)
|
|
call_rcu(&ac_old->rcu, auditd_conn_free);
|
|
|
|
/* flush the retry queue to the hold queue, but don't touch the main
|
|
* queue since we need to process that normally for multicast */
|
|
while ((skb = skb_dequeue(&audit_retry_queue)))
|
|
kauditd_hold_skb(skb);
|
|
}
|
|
|
|
/**
|
|
* auditd_send_unicast_skb - Send a record via unicast to auditd
|
|
* @skb: audit record
|
|
*
|
|
* Description:
|
|
* Send a skb to the audit daemon, returns positive/zero values on success and
|
|
* negative values on failure; in all cases the skb will be consumed by this
|
|
* function. If the send results in -ECONNREFUSED the connection with auditd
|
|
* will be reset. This function may sleep so callers should not hold any locks
|
|
* where this would cause a problem.
|
|
*/
|
|
static int auditd_send_unicast_skb(struct sk_buff *skb)
|
|
{
|
|
int rc;
|
|
u32 portid;
|
|
struct net *net;
|
|
struct sock *sk;
|
|
struct auditd_connection *ac;
|
|
|
|
/* NOTE: we can't call netlink_unicast while in the RCU section so
|
|
* take a reference to the network namespace and grab local
|
|
* copies of the namespace, the sock, and the portid; the
|
|
* namespace and sock aren't going to go away while we hold a
|
|
* reference and if the portid does become invalid after the RCU
|
|
* section netlink_unicast() should safely return an error */
|
|
|
|
rcu_read_lock();
|
|
ac = rcu_dereference(auditd_conn);
|
|
if (!ac) {
|
|
rcu_read_unlock();
|
|
kfree_skb(skb);
|
|
rc = -ECONNREFUSED;
|
|
goto err;
|
|
}
|
|
net = get_net(ac->net);
|
|
sk = audit_get_sk(net);
|
|
portid = ac->portid;
|
|
rcu_read_unlock();
|
|
|
|
rc = netlink_unicast(sk, skb, portid, 0);
|
|
put_net(net);
|
|
if (rc < 0)
|
|
goto err;
|
|
|
|
return rc;
|
|
|
|
err:
|
|
if (ac && rc == -ECONNREFUSED)
|
|
auditd_reset(ac);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* kauditd_send_queue - Helper for kauditd_thread to flush skb queues
|
|
* @sk: the sending sock
|
|
* @portid: the netlink destination
|
|
* @queue: the skb queue to process
|
|
* @retry_limit: limit on number of netlink unicast failures
|
|
* @skb_hook: per-skb hook for additional processing
|
|
* @err_hook: hook called if the skb fails the netlink unicast send
|
|
*
|
|
* Description:
|
|
* Run through the given queue and attempt to send the audit records to auditd,
|
|
* returns zero on success, negative values on failure. It is up to the caller
|
|
* to ensure that the @sk is valid for the duration of this function.
|
|
*
|
|
*/
|
|
static int kauditd_send_queue(struct sock *sk, u32 portid,
|
|
struct sk_buff_head *queue,
|
|
unsigned int retry_limit,
|
|
void (*skb_hook)(struct sk_buff *skb),
|
|
void (*err_hook)(struct sk_buff *skb))
|
|
{
|
|
int rc = 0;
|
|
struct sk_buff *skb;
|
|
static unsigned int failed = 0;
|
|
|
|
/* NOTE: kauditd_thread takes care of all our locking, we just use
|
|
* the netlink info passed to us (e.g. sk and portid) */
|
|
|
|
while ((skb = skb_dequeue(queue))) {
|
|
/* call the skb_hook for each skb we touch */
|
|
if (skb_hook)
|
|
(*skb_hook)(skb);
|
|
|
|
/* can we send to anyone via unicast? */
|
|
if (!sk) {
|
|
if (err_hook)
|
|
(*err_hook)(skb);
|
|
continue;
|
|
}
|
|
|
|
/* grab an extra skb reference in case of error */
|
|
skb_get(skb);
|
|
rc = netlink_unicast(sk, skb, portid, 0);
|
|
if (rc < 0) {
|
|
/* fatal failure for our queue flush attempt? */
|
|
if (++failed >= retry_limit ||
|
|
rc == -ECONNREFUSED || rc == -EPERM) {
|
|
/* yes - error processing for the queue */
|
|
sk = NULL;
|
|
if (err_hook)
|
|
(*err_hook)(skb);
|
|
if (!skb_hook)
|
|
goto out;
|
|
/* keep processing with the skb_hook */
|
|
continue;
|
|
} else
|
|
/* no - requeue to preserve ordering */
|
|
skb_queue_head(queue, skb);
|
|
} else {
|
|
/* it worked - drop the extra reference and continue */
|
|
consume_skb(skb);
|
|
failed = 0;
|
|
}
|
|
}
|
|
|
|
out:
|
|
return (rc >= 0 ? 0 : rc);
|
|
}
|
|
|
|
/*
|
|
* kauditd_send_multicast_skb - Send a record to any multicast listeners
|
|
* @skb: audit record
|
|
*
|
|
* Description:
|
|
* Write a multicast message to anyone listening in the initial network
|
|
* namespace. This function doesn't consume an skb as might be expected since
|
|
* it has to copy it anyways.
|
|
*/
|
|
static void kauditd_send_multicast_skb(struct sk_buff *skb)
|
|
{
|
|
struct sk_buff *copy;
|
|
struct sock *sock = audit_get_sk(&init_net);
|
|
struct nlmsghdr *nlh;
|
|
|
|
/* NOTE: we are not taking an additional reference for init_net since
|
|
* we don't have to worry about it going away */
|
|
|
|
if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
|
|
return;
|
|
|
|
/*
|
|
* The seemingly wasteful skb_copy() rather than bumping the refcount
|
|
* using skb_get() is necessary because non-standard mods are made to
|
|
* the skb by the original kaudit unicast socket send routine. The
|
|
* existing auditd daemon assumes this breakage. Fixing this would
|
|
* require co-ordinating a change in the established protocol between
|
|
* the kaudit kernel subsystem and the auditd userspace code. There is
|
|
* no reason for new multicast clients to continue with this
|
|
* non-compliance.
|
|
*/
|
|
copy = skb_copy(skb, GFP_KERNEL);
|
|
if (!copy)
|
|
return;
|
|
nlh = nlmsg_hdr(copy);
|
|
nlh->nlmsg_len = skb->len;
|
|
|
|
nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, GFP_KERNEL);
|
|
}
|
|
|
|
/**
|
|
* kauditd_thread - Worker thread to send audit records to userspace
|
|
* @dummy: unused
|
|
*/
|
|
static int kauditd_thread(void *dummy)
|
|
{
|
|
int rc;
|
|
u32 portid = 0;
|
|
struct net *net = NULL;
|
|
struct sock *sk = NULL;
|
|
struct auditd_connection *ac;
|
|
|
|
#define UNICAST_RETRIES 5
|
|
|
|
set_freezable();
|
|
while (!kthread_should_stop()) {
|
|
/* NOTE: see the lock comments in auditd_send_unicast_skb() */
|
|
rcu_read_lock();
|
|
ac = rcu_dereference(auditd_conn);
|
|
if (!ac) {
|
|
rcu_read_unlock();
|
|
goto main_queue;
|
|
}
|
|
net = get_net(ac->net);
|
|
sk = audit_get_sk(net);
|
|
portid = ac->portid;
|
|
rcu_read_unlock();
|
|
|
|
/* attempt to flush the hold queue */
|
|
rc = kauditd_send_queue(sk, portid,
|
|
&audit_hold_queue, UNICAST_RETRIES,
|
|
NULL, kauditd_rehold_skb);
|
|
if (rc < 0) {
|
|
sk = NULL;
|
|
auditd_reset(ac);
|
|
goto main_queue;
|
|
}
|
|
|
|
/* attempt to flush the retry queue */
|
|
rc = kauditd_send_queue(sk, portid,
|
|
&audit_retry_queue, UNICAST_RETRIES,
|
|
NULL, kauditd_hold_skb);
|
|
if (rc < 0) {
|
|
sk = NULL;
|
|
auditd_reset(ac);
|
|
goto main_queue;
|
|
}
|
|
|
|
main_queue:
|
|
/* process the main queue - do the multicast send and attempt
|
|
* unicast, dump failed record sends to the retry queue; if
|
|
* sk == NULL due to previous failures we will just do the
|
|
* multicast send and move the record to the hold queue */
|
|
rc = kauditd_send_queue(sk, portid, &audit_queue, 1,
|
|
kauditd_send_multicast_skb,
|
|
(sk ?
|
|
kauditd_retry_skb : kauditd_hold_skb));
|
|
if (ac && rc < 0)
|
|
auditd_reset(ac);
|
|
sk = NULL;
|
|
|
|
/* drop our netns reference, no auditd sends past this line */
|
|
if (net) {
|
|
put_net(net);
|
|
net = NULL;
|
|
}
|
|
|
|
/* we have processed all the queues so wake everyone */
|
|
wake_up(&audit_backlog_wait);
|
|
|
|
/* NOTE: we want to wake up if there is anything on the queue,
|
|
* regardless of if an auditd is connected, as we need to
|
|
* do the multicast send and rotate records from the
|
|
* main queue to the retry/hold queues */
|
|
wait_event_freezable(kauditd_wait,
|
|
(skb_queue_len(&audit_queue) ? 1 : 0));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int audit_send_list_thread(void *_dest)
|
|
{
|
|
struct audit_netlink_list *dest = _dest;
|
|
struct sk_buff *skb;
|
|
struct sock *sk = audit_get_sk(dest->net);
|
|
|
|
/* wait for parent to finish and send an ACK */
|
|
audit_ctl_lock();
|
|
audit_ctl_unlock();
|
|
|
|
while ((skb = __skb_dequeue(&dest->q)) != NULL)
|
|
netlink_unicast(sk, skb, dest->portid, 0);
|
|
|
|
put_net(dest->net);
|
|
kfree(dest);
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct sk_buff *audit_make_reply(int seq, int type, int done,
|
|
int multi, const void *payload, int size)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct nlmsghdr *nlh;
|
|
void *data;
|
|
int flags = multi ? NLM_F_MULTI : 0;
|
|
int t = done ? NLMSG_DONE : type;
|
|
|
|
skb = nlmsg_new(size, GFP_KERNEL);
|
|
if (!skb)
|
|
return NULL;
|
|
|
|
nlh = nlmsg_put(skb, 0, seq, t, size, flags);
|
|
if (!nlh)
|
|
goto out_kfree_skb;
|
|
data = nlmsg_data(nlh);
|
|
memcpy(data, payload, size);
|
|
return skb;
|
|
|
|
out_kfree_skb:
|
|
kfree_skb(skb);
|
|
return NULL;
|
|
}
|
|
|
|
static void audit_free_reply(struct audit_reply *reply)
|
|
{
|
|
if (!reply)
|
|
return;
|
|
|
|
kfree_skb(reply->skb);
|
|
if (reply->net)
|
|
put_net(reply->net);
|
|
kfree(reply);
|
|
}
|
|
|
|
static int audit_send_reply_thread(void *arg)
|
|
{
|
|
struct audit_reply *reply = (struct audit_reply *)arg;
|
|
|
|
audit_ctl_lock();
|
|
audit_ctl_unlock();
|
|
|
|
/* Ignore failure. It'll only happen if the sender goes away,
|
|
because our timeout is set to infinite. */
|
|
netlink_unicast(audit_get_sk(reply->net), reply->skb, reply->portid, 0);
|
|
reply->skb = NULL;
|
|
audit_free_reply(reply);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* audit_send_reply - send an audit reply message via netlink
|
|
* @request_skb: skb of request we are replying to (used to target the reply)
|
|
* @seq: sequence number
|
|
* @type: audit message type
|
|
* @done: done (last) flag
|
|
* @multi: multi-part message flag
|
|
* @payload: payload data
|
|
* @size: payload size
|
|
*
|
|
* Allocates a skb, builds the netlink message, and sends it to the port id.
|
|
*/
|
|
static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
|
|
int multi, const void *payload, int size)
|
|
{
|
|
struct task_struct *tsk;
|
|
struct audit_reply *reply;
|
|
|
|
reply = kzalloc(sizeof(*reply), GFP_KERNEL);
|
|
if (!reply)
|
|
return;
|
|
|
|
reply->skb = audit_make_reply(seq, type, done, multi, payload, size);
|
|
if (!reply->skb)
|
|
goto err;
|
|
reply->net = get_net(sock_net(NETLINK_CB(request_skb).sk));
|
|
reply->portid = NETLINK_CB(request_skb).portid;
|
|
|
|
tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
|
|
if (IS_ERR(tsk))
|
|
goto err;
|
|
|
|
return;
|
|
|
|
err:
|
|
audit_free_reply(reply);
|
|
}
|
|
|
|
/*
|
|
* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
|
|
* control messages.
|
|
*/
|
|
static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
|
|
{
|
|
int err = 0;
|
|
|
|
/* Only support initial user namespace for now. */
|
|
/*
|
|
* We return ECONNREFUSED because it tricks userspace into thinking
|
|
* that audit was not configured into the kernel. Lots of users
|
|
* configure their PAM stack (because that's what the distro does)
|
|
* to reject login if unable to send messages to audit. If we return
|
|
* ECONNREFUSED the PAM stack thinks the kernel does not have audit
|
|
* configured in and will let login proceed. If we return EPERM
|
|
* userspace will reject all logins. This should be removed when we
|
|
* support non init namespaces!!
|
|
*/
|
|
if (current_user_ns() != &init_user_ns)
|
|
return -ECONNREFUSED;
|
|
|
|
switch (msg_type) {
|
|
case AUDIT_LIST:
|
|
case AUDIT_ADD:
|
|
case AUDIT_DEL:
|
|
return -EOPNOTSUPP;
|
|
case AUDIT_GET:
|
|
case AUDIT_SET:
|
|
case AUDIT_GET_FEATURE:
|
|
case AUDIT_SET_FEATURE:
|
|
case AUDIT_LIST_RULES:
|
|
case AUDIT_ADD_RULE:
|
|
case AUDIT_DEL_RULE:
|
|
case AUDIT_SIGNAL_INFO:
|
|
case AUDIT_TTY_GET:
|
|
case AUDIT_TTY_SET:
|
|
case AUDIT_TRIM:
|
|
case AUDIT_MAKE_EQUIV:
|
|
/* Only support auditd and auditctl in initial pid namespace
|
|
* for now. */
|
|
if (task_active_pid_ns(current) != &init_pid_ns)
|
|
return -EPERM;
|
|
|
|
if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
|
|
err = -EPERM;
|
|
break;
|
|
case AUDIT_USER:
|
|
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
|
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
|
if (!netlink_capable(skb, CAP_AUDIT_WRITE))
|
|
err = -EPERM;
|
|
break;
|
|
default: /* bad msg */
|
|
err = -EINVAL;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static void audit_log_common_recv_msg(struct audit_context *context,
|
|
struct audit_buffer **ab, u16 msg_type)
|
|
{
|
|
uid_t uid = from_kuid(&init_user_ns, current_uid());
|
|
pid_t pid = task_tgid_nr(current);
|
|
|
|
if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
|
|
*ab = NULL;
|
|
return;
|
|
}
|
|
|
|
*ab = audit_log_start(context, GFP_KERNEL, msg_type);
|
|
if (unlikely(!*ab))
|
|
return;
|
|
audit_log_format(*ab, "pid=%d uid=%u ", pid, uid);
|
|
audit_log_session_info(*ab);
|
|
audit_log_task_context(*ab);
|
|
}
|
|
|
|
static inline void audit_log_user_recv_msg(struct audit_buffer **ab,
|
|
u16 msg_type)
|
|
{
|
|
audit_log_common_recv_msg(NULL, ab, msg_type);
|
|
}
|
|
|
|
int is_audit_feature_set(int i)
|
|
{
|
|
return af.features & AUDIT_FEATURE_TO_MASK(i);
|
|
}
|
|
|
|
|
|
static int audit_get_feature(struct sk_buff *skb)
|
|
{
|
|
u32 seq;
|
|
|
|
seq = nlmsg_hdr(skb)->nlmsg_seq;
|
|
|
|
audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
|
|
u32 old_lock, u32 new_lock, int res)
|
|
{
|
|
struct audit_buffer *ab;
|
|
|
|
if (audit_enabled == AUDIT_OFF)
|
|
return;
|
|
|
|
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_FEATURE_CHANGE);
|
|
if (!ab)
|
|
return;
|
|
audit_log_task_info(ab);
|
|
audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
|
|
audit_feature_names[which], !!old_feature, !!new_feature,
|
|
!!old_lock, !!new_lock, res);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
static int audit_set_feature(struct audit_features *uaf)
|
|
{
|
|
int i;
|
|
|
|
BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
|
|
|
|
/* if there is ever a version 2 we should handle that here */
|
|
|
|
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
|
|
u32 feature = AUDIT_FEATURE_TO_MASK(i);
|
|
u32 old_feature, new_feature, old_lock, new_lock;
|
|
|
|
/* if we are not changing this feature, move along */
|
|
if (!(feature & uaf->mask))
|
|
continue;
|
|
|
|
old_feature = af.features & feature;
|
|
new_feature = uaf->features & feature;
|
|
new_lock = (uaf->lock | af.lock) & feature;
|
|
old_lock = af.lock & feature;
|
|
|
|
/* are we changing a locked feature? */
|
|
if (old_lock && (new_feature != old_feature)) {
|
|
audit_log_feature_change(i, old_feature, new_feature,
|
|
old_lock, new_lock, 0);
|
|
return -EPERM;
|
|
}
|
|
}
|
|
/* nothing invalid, do the changes */
|
|
for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
|
|
u32 feature = AUDIT_FEATURE_TO_MASK(i);
|
|
u32 old_feature, new_feature, old_lock, new_lock;
|
|
|
|
/* if we are not changing this feature, move along */
|
|
if (!(feature & uaf->mask))
|
|
continue;
|
|
|
|
old_feature = af.features & feature;
|
|
new_feature = uaf->features & feature;
|
|
old_lock = af.lock & feature;
|
|
new_lock = (uaf->lock | af.lock) & feature;
|
|
|
|
if (new_feature != old_feature)
|
|
audit_log_feature_change(i, old_feature, new_feature,
|
|
old_lock, new_lock, 1);
|
|
|
|
if (new_feature)
|
|
af.features |= feature;
|
|
else
|
|
af.features &= ~feature;
|
|
af.lock |= new_lock;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int audit_replace(struct pid *pid)
|
|
{
|
|
pid_t pvnr;
|
|
struct sk_buff *skb;
|
|
|
|
pvnr = pid_vnr(pid);
|
|
skb = audit_make_reply(0, AUDIT_REPLACE, 0, 0, &pvnr, sizeof(pvnr));
|
|
if (!skb)
|
|
return -ENOMEM;
|
|
return auditd_send_unicast_skb(skb);
|
|
}
|
|
|
|
static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
|
{
|
|
u32 seq;
|
|
void *data;
|
|
int data_len;
|
|
int err;
|
|
struct audit_buffer *ab;
|
|
u16 msg_type = nlh->nlmsg_type;
|
|
struct audit_sig_info *sig_data;
|
|
char *ctx = NULL;
|
|
u32 len;
|
|
|
|
err = audit_netlink_ok(skb, msg_type);
|
|
if (err)
|
|
return err;
|
|
|
|
seq = nlh->nlmsg_seq;
|
|
data = nlmsg_data(nlh);
|
|
data_len = nlmsg_len(nlh);
|
|
|
|
switch (msg_type) {
|
|
case AUDIT_GET: {
|
|
struct audit_status s;
|
|
memset(&s, 0, sizeof(s));
|
|
s.enabled = audit_enabled;
|
|
s.failure = audit_failure;
|
|
/* NOTE: use pid_vnr() so the PID is relative to the current
|
|
* namespace */
|
|
s.pid = auditd_pid_vnr();
|
|
s.rate_limit = audit_rate_limit;
|
|
s.backlog_limit = audit_backlog_limit;
|
|
s.lost = atomic_read(&audit_lost);
|
|
s.backlog = skb_queue_len(&audit_queue);
|
|
s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
|
|
s.backlog_wait_time = audit_backlog_wait_time;
|
|
s.backlog_wait_time_actual = atomic_read(&audit_backlog_wait_time_actual);
|
|
audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
|
|
break;
|
|
}
|
|
case AUDIT_SET: {
|
|
struct audit_status s;
|
|
memset(&s, 0, sizeof(s));
|
|
/* guard against past and future API changes */
|
|
memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
|
|
if (s.mask & AUDIT_STATUS_ENABLED) {
|
|
err = audit_set_enabled(s.enabled);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
if (s.mask & AUDIT_STATUS_FAILURE) {
|
|
err = audit_set_failure(s.failure);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
if (s.mask & AUDIT_STATUS_PID) {
|
|
/* NOTE: we are using the vnr PID functions below
|
|
* because the s.pid value is relative to the
|
|
* namespace of the caller; at present this
|
|
* doesn't matter much since you can really only
|
|
* run auditd from the initial pid namespace, but
|
|
* something to keep in mind if this changes */
|
|
pid_t new_pid = s.pid;
|
|
pid_t auditd_pid;
|
|
struct pid *req_pid = task_tgid(current);
|
|
|
|
/* Sanity check - PID values must match. Setting
|
|
* pid to 0 is how auditd ends auditing. */
|
|
if (new_pid && (new_pid != pid_vnr(req_pid)))
|
|
return -EINVAL;
|
|
|
|
/* test the auditd connection */
|
|
audit_replace(req_pid);
|
|
|
|
auditd_pid = auditd_pid_vnr();
|
|
if (auditd_pid) {
|
|
/* replacing a healthy auditd is not allowed */
|
|
if (new_pid) {
|
|
audit_log_config_change("audit_pid",
|
|
new_pid, auditd_pid, 0);
|
|
return -EEXIST;
|
|
}
|
|
/* only current auditd can unregister itself */
|
|
if (pid_vnr(req_pid) != auditd_pid) {
|
|
audit_log_config_change("audit_pid",
|
|
new_pid, auditd_pid, 0);
|
|
return -EACCES;
|
|
}
|
|
}
|
|
|
|
if (new_pid) {
|
|
/* register a new auditd connection */
|
|
err = auditd_set(req_pid,
|
|
NETLINK_CB(skb).portid,
|
|
sock_net(NETLINK_CB(skb).sk));
|
|
if (audit_enabled != AUDIT_OFF)
|
|
audit_log_config_change("audit_pid",
|
|
new_pid,
|
|
auditd_pid,
|
|
err ? 0 : 1);
|
|
if (err)
|
|
return err;
|
|
|
|
/* try to process any backlog */
|
|
wake_up_interruptible(&kauditd_wait);
|
|
} else {
|
|
if (audit_enabled != AUDIT_OFF)
|
|
audit_log_config_change("audit_pid",
|
|
new_pid,
|
|
auditd_pid, 1);
|
|
|
|
/* unregister the auditd connection */
|
|
auditd_reset(NULL);
|
|
}
|
|
}
|
|
if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
|
|
err = audit_set_rate_limit(s.rate_limit);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
|
|
err = audit_set_backlog_limit(s.backlog_limit);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
|
|
if (sizeof(s) > (size_t)nlh->nlmsg_len)
|
|
return -EINVAL;
|
|
if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
|
|
return -EINVAL;
|
|
err = audit_set_backlog_wait_time(s.backlog_wait_time);
|
|
if (err < 0)
|
|
return err;
|
|
}
|
|
if (s.mask == AUDIT_STATUS_LOST) {
|
|
u32 lost = atomic_xchg(&audit_lost, 0);
|
|
|
|
audit_log_config_change("lost", 0, lost, 1);
|
|
return lost;
|
|
}
|
|
if (s.mask == AUDIT_STATUS_BACKLOG_WAIT_TIME_ACTUAL) {
|
|
u32 actual = atomic_xchg(&audit_backlog_wait_time_actual, 0);
|
|
|
|
audit_log_config_change("backlog_wait_time_actual", 0, actual, 1);
|
|
return actual;
|
|
}
|
|
break;
|
|
}
|
|
case AUDIT_GET_FEATURE:
|
|
err = audit_get_feature(skb);
|
|
if (err)
|
|
return err;
|
|
break;
|
|
case AUDIT_SET_FEATURE:
|
|
if (data_len < sizeof(struct audit_features))
|
|
return -EINVAL;
|
|
err = audit_set_feature(data);
|
|
if (err)
|
|
return err;
|
|
break;
|
|
case AUDIT_USER:
|
|
case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
|
case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
|
if (!audit_enabled && msg_type != AUDIT_USER_AVC)
|
|
return 0;
|
|
/* exit early if there isn't at least one character to print */
|
|
if (data_len < 2)
|
|
return -EINVAL;
|
|
|
|
err = audit_filter(msg_type, AUDIT_FILTER_USER);
|
|
if (err == 1) { /* match or error */
|
|
char *str = data;
|
|
|
|
err = 0;
|
|
if (msg_type == AUDIT_USER_TTY) {
|
|
err = tty_audit_push();
|
|
if (err)
|
|
break;
|
|
}
|
|
audit_log_user_recv_msg(&ab, msg_type);
|
|
if (msg_type != AUDIT_USER_TTY) {
|
|
/* ensure NULL termination */
|
|
str[data_len - 1] = '\0';
|
|
audit_log_format(ab, " msg='%.*s'",
|
|
AUDIT_MESSAGE_TEXT_MAX,
|
|
str);
|
|
} else {
|
|
audit_log_format(ab, " data=");
|
|
if (data_len > 0 && str[data_len - 1] == '\0')
|
|
data_len--;
|
|
audit_log_n_untrustedstring(ab, str, data_len);
|
|
}
|
|
audit_log_end(ab);
|
|
}
|
|
break;
|
|
case AUDIT_ADD_RULE:
|
|
case AUDIT_DEL_RULE:
|
|
if (data_len < sizeof(struct audit_rule_data))
|
|
return -EINVAL;
|
|
if (audit_enabled == AUDIT_LOCKED) {
|
|
audit_log_common_recv_msg(audit_context(), &ab,
|
|
AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " op=%s audit_enabled=%d res=0",
|
|
msg_type == AUDIT_ADD_RULE ?
|
|
"add_rule" : "remove_rule",
|
|
audit_enabled);
|
|
audit_log_end(ab);
|
|
return -EPERM;
|
|
}
|
|
err = audit_rule_change(msg_type, seq, data, data_len);
|
|
break;
|
|
case AUDIT_LIST_RULES:
|
|
err = audit_list_rules_send(skb, seq);
|
|
break;
|
|
case AUDIT_TRIM:
|
|
audit_trim_trees();
|
|
audit_log_common_recv_msg(audit_context(), &ab,
|
|
AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " op=trim res=1");
|
|
audit_log_end(ab);
|
|
break;
|
|
case AUDIT_MAKE_EQUIV: {
|
|
void *bufp = data;
|
|
u32 sizes[2];
|
|
size_t msglen = data_len;
|
|
char *old, *new;
|
|
|
|
err = -EINVAL;
|
|
if (msglen < 2 * sizeof(u32))
|
|
break;
|
|
memcpy(sizes, bufp, 2 * sizeof(u32));
|
|
bufp += 2 * sizeof(u32);
|
|
msglen -= 2 * sizeof(u32);
|
|
old = audit_unpack_string(&bufp, &msglen, sizes[0]);
|
|
if (IS_ERR(old)) {
|
|
err = PTR_ERR(old);
|
|
break;
|
|
}
|
|
new = audit_unpack_string(&bufp, &msglen, sizes[1]);
|
|
if (IS_ERR(new)) {
|
|
err = PTR_ERR(new);
|
|
kfree(old);
|
|
break;
|
|
}
|
|
/* OK, here comes... */
|
|
err = audit_tag_tree(old, new);
|
|
|
|
audit_log_common_recv_msg(audit_context(), &ab,
|
|
AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " op=make_equiv old=");
|
|
audit_log_untrustedstring(ab, old);
|
|
audit_log_format(ab, " new=");
|
|
audit_log_untrustedstring(ab, new);
|
|
audit_log_format(ab, " res=%d", !err);
|
|
audit_log_end(ab);
|
|
kfree(old);
|
|
kfree(new);
|
|
break;
|
|
}
|
|
case AUDIT_SIGNAL_INFO:
|
|
len = 0;
|
|
if (audit_sig_sid) {
|
|
err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
|
|
if (err)
|
|
return err;
|
|
}
|
|
sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
|
|
if (!sig_data) {
|
|
if (audit_sig_sid)
|
|
security_release_secctx(ctx, len);
|
|
return -ENOMEM;
|
|
}
|
|
sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
|
|
sig_data->pid = audit_sig_pid;
|
|
if (audit_sig_sid) {
|
|
memcpy(sig_data->ctx, ctx, len);
|
|
security_release_secctx(ctx, len);
|
|
}
|
|
audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
|
|
sig_data, sizeof(*sig_data) + len);
|
|
kfree(sig_data);
|
|
break;
|
|
case AUDIT_TTY_GET: {
|
|
struct audit_tty_status s;
|
|
unsigned int t;
|
|
|
|
t = READ_ONCE(current->signal->audit_tty);
|
|
s.enabled = t & AUDIT_TTY_ENABLE;
|
|
s.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
|
|
|
|
audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
|
|
break;
|
|
}
|
|
case AUDIT_TTY_SET: {
|
|
struct audit_tty_status s, old;
|
|
struct audit_buffer *ab;
|
|
unsigned int t;
|
|
|
|
memset(&s, 0, sizeof(s));
|
|
/* guard against past and future API changes */
|
|
memcpy(&s, data, min_t(size_t, sizeof(s), data_len));
|
|
/* check if new data is valid */
|
|
if ((s.enabled != 0 && s.enabled != 1) ||
|
|
(s.log_passwd != 0 && s.log_passwd != 1))
|
|
err = -EINVAL;
|
|
|
|
if (err)
|
|
t = READ_ONCE(current->signal->audit_tty);
|
|
else {
|
|
t = s.enabled | (-s.log_passwd & AUDIT_TTY_LOG_PASSWD);
|
|
t = xchg(¤t->signal->audit_tty, t);
|
|
}
|
|
old.enabled = t & AUDIT_TTY_ENABLE;
|
|
old.log_passwd = !!(t & AUDIT_TTY_LOG_PASSWD);
|
|
|
|
audit_log_common_recv_msg(audit_context(), &ab,
|
|
AUDIT_CONFIG_CHANGE);
|
|
audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
|
|
" old-log_passwd=%d new-log_passwd=%d res=%d",
|
|
old.enabled, s.enabled, old.log_passwd,
|
|
s.log_passwd, !err);
|
|
audit_log_end(ab);
|
|
break;
|
|
}
|
|
default:
|
|
err = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
return err < 0 ? err : 0;
|
|
}
|
|
|
|
/**
|
|
* audit_receive - receive messages from a netlink control socket
|
|
* @skb: the message buffer
|
|
*
|
|
* Parse the provided skb and deal with any messages that may be present,
|
|
* malformed skbs are discarded.
|
|
*/
|
|
static void audit_receive(struct sk_buff *skb)
|
|
{
|
|
struct nlmsghdr *nlh;
|
|
/*
|
|
* len MUST be signed for nlmsg_next to be able to dec it below 0
|
|
* if the nlmsg_len was not aligned
|
|
*/
|
|
int len;
|
|
int err;
|
|
|
|
nlh = nlmsg_hdr(skb);
|
|
len = skb->len;
|
|
|
|
audit_ctl_lock();
|
|
while (nlmsg_ok(nlh, len)) {
|
|
err = audit_receive_msg(skb, nlh);
|
|
/* if err or if this message says it wants a response */
|
|
if (err || (nlh->nlmsg_flags & NLM_F_ACK))
|
|
netlink_ack(skb, nlh, err, NULL);
|
|
|
|
nlh = nlmsg_next(nlh, &len);
|
|
}
|
|
audit_ctl_unlock();
|
|
}
|
|
|
|
/* Log information about who is connecting to the audit multicast socket */
|
|
static void audit_log_multicast(int group, const char *op, int err)
|
|
{
|
|
const struct cred *cred;
|
|
struct tty_struct *tty;
|
|
char comm[sizeof(current->comm)];
|
|
struct audit_buffer *ab;
|
|
|
|
if (!audit_enabled)
|
|
return;
|
|
|
|
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
|
|
if (!ab)
|
|
return;
|
|
|
|
cred = current_cred();
|
|
tty = audit_get_tty();
|
|
audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
|
|
task_pid_nr(current),
|
|
from_kuid(&init_user_ns, cred->uid),
|
|
from_kuid(&init_user_ns, audit_get_loginuid(current)),
|
|
tty ? tty_name(tty) : "(none)",
|
|
audit_get_sessionid(current));
|
|
audit_put_tty(tty);
|
|
audit_log_task_context(ab); /* subj= */
|
|
audit_log_format(ab, " comm=");
|
|
audit_log_untrustedstring(ab, get_task_comm(comm, current));
|
|
audit_log_d_path_exe(ab, current->mm); /* exe= */
|
|
audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
/* Run custom bind function on netlink socket group connect or bind requests. */
|
|
static int audit_multicast_bind(struct net *net, int group)
|
|
{
|
|
int err = 0;
|
|
|
|
if (!capable(CAP_AUDIT_READ))
|
|
err = -EPERM;
|
|
audit_log_multicast(group, "connect", err);
|
|
return err;
|
|
}
|
|
|
|
static void audit_multicast_unbind(struct net *net, int group)
|
|
{
|
|
audit_log_multicast(group, "disconnect", 0);
|
|
}
|
|
|
|
static int __net_init audit_net_init(struct net *net)
|
|
{
|
|
struct netlink_kernel_cfg cfg = {
|
|
.input = audit_receive,
|
|
.bind = audit_multicast_bind,
|
|
.unbind = audit_multicast_unbind,
|
|
.flags = NL_CFG_F_NONROOT_RECV,
|
|
.groups = AUDIT_NLGRP_MAX,
|
|
};
|
|
|
|
struct audit_net *aunet = net_generic(net, audit_net_id);
|
|
|
|
aunet->sk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
|
|
if (aunet->sk == NULL) {
|
|
audit_panic("cannot initialize netlink socket in namespace");
|
|
return -ENOMEM;
|
|
}
|
|
aunet->sk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void __net_exit audit_net_exit(struct net *net)
|
|
{
|
|
struct audit_net *aunet = net_generic(net, audit_net_id);
|
|
|
|
/* NOTE: you would think that we would want to check the auditd
|
|
* connection and potentially reset it here if it lives in this
|
|
* namespace, but since the auditd connection tracking struct holds a
|
|
* reference to this namespace (see auditd_set()) we are only ever
|
|
* going to get here after that connection has been released */
|
|
|
|
netlink_kernel_release(aunet->sk);
|
|
}
|
|
|
|
static struct pernet_operations audit_net_ops __net_initdata = {
|
|
.init = audit_net_init,
|
|
.exit = audit_net_exit,
|
|
.id = &audit_net_id,
|
|
.size = sizeof(struct audit_net),
|
|
};
|
|
|
|
/* Initialize audit support at boot time. */
|
|
static int __init audit_init(void)
|
|
{
|
|
int i;
|
|
|
|
if (audit_initialized == AUDIT_DISABLED)
|
|
return 0;
|
|
|
|
audit_buffer_cache = kmem_cache_create("audit_buffer",
|
|
sizeof(struct audit_buffer),
|
|
0, SLAB_PANIC, NULL);
|
|
|
|
skb_queue_head_init(&audit_queue);
|
|
skb_queue_head_init(&audit_retry_queue);
|
|
skb_queue_head_init(&audit_hold_queue);
|
|
|
|
for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
|
|
INIT_LIST_HEAD(&audit_inode_hash[i]);
|
|
|
|
mutex_init(&audit_cmd_mutex.lock);
|
|
audit_cmd_mutex.owner = NULL;
|
|
|
|
pr_info("initializing netlink subsys (%s)\n",
|
|
audit_default ? "enabled" : "disabled");
|
|
register_pernet_subsys(&audit_net_ops);
|
|
|
|
audit_initialized = AUDIT_INITIALIZED;
|
|
|
|
kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
|
|
if (IS_ERR(kauditd_task)) {
|
|
int err = PTR_ERR(kauditd_task);
|
|
panic("audit: failed to start the kauditd thread (%d)\n", err);
|
|
}
|
|
|
|
audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL,
|
|
"state=initialized audit_enabled=%u res=1",
|
|
audit_enabled);
|
|
|
|
return 0;
|
|
}
|
|
postcore_initcall(audit_init);
|
|
|
|
/*
|
|
* Process kernel command-line parameter at boot time.
|
|
* audit={0|off} or audit={1|on}.
|
|
*/
|
|
static int __init audit_enable(char *str)
|
|
{
|
|
if (!strcasecmp(str, "off") || !strcmp(str, "0"))
|
|
audit_default = AUDIT_OFF;
|
|
else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
|
|
audit_default = AUDIT_ON;
|
|
else {
|
|
pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
|
|
audit_default = AUDIT_ON;
|
|
}
|
|
|
|
if (audit_default == AUDIT_OFF)
|
|
audit_initialized = AUDIT_DISABLED;
|
|
if (audit_set_enabled(audit_default))
|
|
pr_err("audit: error setting audit state (%d)\n",
|
|
audit_default);
|
|
|
|
pr_info("%s\n", audit_default ?
|
|
"enabled (after initialization)" : "disabled (until reboot)");
|
|
|
|
return 1;
|
|
}
|
|
__setup("audit=", audit_enable);
|
|
|
|
/* Process kernel command-line parameter at boot time.
|
|
* audit_backlog_limit=<n> */
|
|
static int __init audit_backlog_limit_set(char *str)
|
|
{
|
|
u32 audit_backlog_limit_arg;
|
|
|
|
pr_info("audit_backlog_limit: ");
|
|
if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
|
|
pr_cont("using default of %u, unable to parse %s\n",
|
|
audit_backlog_limit, str);
|
|
return 1;
|
|
}
|
|
|
|
audit_backlog_limit = audit_backlog_limit_arg;
|
|
pr_cont("%d\n", audit_backlog_limit);
|
|
|
|
return 1;
|
|
}
|
|
__setup("audit_backlog_limit=", audit_backlog_limit_set);
|
|
|
|
static void audit_buffer_free(struct audit_buffer *ab)
|
|
{
|
|
if (!ab)
|
|
return;
|
|
|
|
kfree_skb(ab->skb);
|
|
kmem_cache_free(audit_buffer_cache, ab);
|
|
}
|
|
|
|
static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx,
|
|
gfp_t gfp_mask, int type)
|
|
{
|
|
struct audit_buffer *ab;
|
|
|
|
ab = kmem_cache_alloc(audit_buffer_cache, gfp_mask);
|
|
if (!ab)
|
|
return NULL;
|
|
|
|
ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
|
|
if (!ab->skb)
|
|
goto err;
|
|
if (!nlmsg_put(ab->skb, 0, 0, type, 0, 0))
|
|
goto err;
|
|
|
|
ab->ctx = ctx;
|
|
ab->gfp_mask = gfp_mask;
|
|
|
|
return ab;
|
|
|
|
err:
|
|
audit_buffer_free(ab);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* audit_serial - compute a serial number for the audit record
|
|
*
|
|
* Compute a serial number for the audit record. Audit records are
|
|
* written to user-space as soon as they are generated, so a complete
|
|
* audit record may be written in several pieces. The timestamp of the
|
|
* record and this serial number are used by the user-space tools to
|
|
* determine which pieces belong to the same audit record. The
|
|
* (timestamp,serial) tuple is unique for each syscall and is live from
|
|
* syscall entry to syscall exit.
|
|
*
|
|
* NOTE: Another possibility is to store the formatted records off the
|
|
* audit context (for those records that have a context), and emit them
|
|
* all at syscall exit. However, this could delay the reporting of
|
|
* significant errors until syscall exit (or never, if the system
|
|
* halts).
|
|
*/
|
|
unsigned int audit_serial(void)
|
|
{
|
|
static atomic_t serial = ATOMIC_INIT(0);
|
|
|
|
return atomic_inc_return(&serial);
|
|
}
|
|
|
|
static inline void audit_get_stamp(struct audit_context *ctx,
|
|
struct timespec64 *t, unsigned int *serial)
|
|
{
|
|
if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
|
|
ktime_get_coarse_real_ts64(t);
|
|
*serial = audit_serial();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* audit_log_start - obtain an audit buffer
|
|
* @ctx: audit_context (may be NULL)
|
|
* @gfp_mask: type of allocation
|
|
* @type: audit message type
|
|
*
|
|
* Returns audit_buffer pointer on success or NULL on error.
|
|
*
|
|
* Obtain an audit buffer. This routine does locking to obtain the
|
|
* audit buffer, but then no locking is required for calls to
|
|
* audit_log_*format. If the task (ctx) is a task that is currently in a
|
|
* syscall, then the syscall is marked as auditable and an audit record
|
|
* will be written at syscall exit. If there is no associated task, then
|
|
* task context (ctx) should be NULL.
|
|
*/
|
|
struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
|
|
int type)
|
|
{
|
|
struct audit_buffer *ab;
|
|
struct timespec64 t;
|
|
unsigned int serial;
|
|
|
|
if (audit_initialized != AUDIT_INITIALIZED)
|
|
return NULL;
|
|
|
|
if (unlikely(!audit_filter(type, AUDIT_FILTER_EXCLUDE)))
|
|
return NULL;
|
|
|
|
/* NOTE: don't ever fail/sleep on these two conditions:
|
|
* 1. auditd generated record - since we need auditd to drain the
|
|
* queue; also, when we are checking for auditd, compare PIDs using
|
|
* task_tgid_vnr() since auditd_pid is set in audit_receive_msg()
|
|
* using a PID anchored in the caller's namespace
|
|
* 2. generator holding the audit_cmd_mutex - we don't want to block
|
|
* while holding the mutex */
|
|
if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
|
|
long stime = audit_backlog_wait_time;
|
|
|
|
while (audit_backlog_limit &&
|
|
(skb_queue_len(&audit_queue) > audit_backlog_limit)) {
|
|
/* wake kauditd to try and flush the queue */
|
|
wake_up_interruptible(&kauditd_wait);
|
|
|
|
/* sleep if we are allowed and we haven't exhausted our
|
|
* backlog wait limit */
|
|
if (gfpflags_allow_blocking(gfp_mask) && (stime > 0)) {
|
|
long rtime = stime;
|
|
|
|
DECLARE_WAITQUEUE(wait, current);
|
|
|
|
add_wait_queue_exclusive(&audit_backlog_wait,
|
|
&wait);
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
stime = schedule_timeout(rtime);
|
|
atomic_add(rtime - stime, &audit_backlog_wait_time_actual);
|
|
remove_wait_queue(&audit_backlog_wait, &wait);
|
|
} else {
|
|
if (audit_rate_check() && printk_ratelimit())
|
|
pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
|
|
skb_queue_len(&audit_queue),
|
|
audit_backlog_limit);
|
|
audit_log_lost("backlog limit exceeded");
|
|
return NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
ab = audit_buffer_alloc(ctx, gfp_mask, type);
|
|
if (!ab) {
|
|
audit_log_lost("out of memory in audit_log_start");
|
|
return NULL;
|
|
}
|
|
|
|
audit_get_stamp(ab->ctx, &t, &serial);
|
|
/* cancel dummy context to enable supporting records */
|
|
if (ctx)
|
|
ctx->dummy = 0;
|
|
audit_log_format(ab, "audit(%llu.%03lu:%u): ",
|
|
(unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
|
|
|
|
return ab;
|
|
}
|
|
|
|
/**
|
|
* audit_expand - expand skb in the audit buffer
|
|
* @ab: audit_buffer
|
|
* @extra: space to add at tail of the skb
|
|
*
|
|
* Returns 0 (no space) on failed expansion, or available space if
|
|
* successful.
|
|
*/
|
|
static inline int audit_expand(struct audit_buffer *ab, int extra)
|
|
{
|
|
struct sk_buff *skb = ab->skb;
|
|
int oldtail = skb_tailroom(skb);
|
|
int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
|
|
int newtail = skb_tailroom(skb);
|
|
|
|
if (ret < 0) {
|
|
audit_log_lost("out of memory in audit_expand");
|
|
return 0;
|
|
}
|
|
|
|
skb->truesize += newtail - oldtail;
|
|
return newtail;
|
|
}
|
|
|
|
/*
|
|
* Format an audit message into the audit buffer. If there isn't enough
|
|
* room in the audit buffer, more room will be allocated and vsnprint
|
|
* will be called a second time. Currently, we assume that a printk
|
|
* can't format message larger than 1024 bytes, so we don't either.
|
|
*/
|
|
static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
|
|
va_list args)
|
|
{
|
|
int len, avail;
|
|
struct sk_buff *skb;
|
|
va_list args2;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
BUG_ON(!ab->skb);
|
|
skb = ab->skb;
|
|
avail = skb_tailroom(skb);
|
|
if (avail == 0) {
|
|
avail = audit_expand(ab, AUDIT_BUFSIZ);
|
|
if (!avail)
|
|
goto out;
|
|
}
|
|
va_copy(args2, args);
|
|
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
|
|
if (len >= avail) {
|
|
/* The printk buffer is 1024 bytes long, so if we get
|
|
* here and AUDIT_BUFSIZ is at least 1024, then we can
|
|
* log everything that printk could have logged. */
|
|
avail = audit_expand(ab,
|
|
max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
|
|
if (!avail)
|
|
goto out_va_end;
|
|
len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
|
|
}
|
|
if (len > 0)
|
|
skb_put(skb, len);
|
|
out_va_end:
|
|
va_end(args2);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* audit_log_format - format a message into the audit buffer.
|
|
* @ab: audit_buffer
|
|
* @fmt: format string
|
|
* @...: optional parameters matching @fmt string
|
|
*
|
|
* All the work is done in audit_log_vformat.
|
|
*/
|
|
void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
|
|
if (!ab)
|
|
return;
|
|
va_start(args, fmt);
|
|
audit_log_vformat(ab, fmt, args);
|
|
va_end(args);
|
|
}
|
|
|
|
/**
|
|
* audit_log_n_hex - convert a buffer to hex and append it to the audit skb
|
|
* @ab: the audit_buffer
|
|
* @buf: buffer to convert to hex
|
|
* @len: length of @buf to be converted
|
|
*
|
|
* No return value; failure to expand is silently ignored.
|
|
*
|
|
* This function will take the passed buf and convert it into a string of
|
|
* ascii hex digits. The new string is placed onto the skb.
|
|
*/
|
|
void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
|
|
size_t len)
|
|
{
|
|
int i, avail, new_len;
|
|
unsigned char *ptr;
|
|
struct sk_buff *skb;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
BUG_ON(!ab->skb);
|
|
skb = ab->skb;
|
|
avail = skb_tailroom(skb);
|
|
new_len = len<<1;
|
|
if (new_len >= avail) {
|
|
/* Round the buffer request up to the next multiple */
|
|
new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
|
|
avail = audit_expand(ab, new_len);
|
|
if (!avail)
|
|
return;
|
|
}
|
|
|
|
ptr = skb_tail_pointer(skb);
|
|
for (i = 0; i < len; i++)
|
|
ptr = hex_byte_pack_upper(ptr, buf[i]);
|
|
*ptr = 0;
|
|
skb_put(skb, len << 1); /* new string is twice the old string */
|
|
}
|
|
|
|
/*
|
|
* Format a string of no more than slen characters into the audit buffer,
|
|
* enclosed in quote marks.
|
|
*/
|
|
void audit_log_n_string(struct audit_buffer *ab, const char *string,
|
|
size_t slen)
|
|
{
|
|
int avail, new_len;
|
|
unsigned char *ptr;
|
|
struct sk_buff *skb;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
BUG_ON(!ab->skb);
|
|
skb = ab->skb;
|
|
avail = skb_tailroom(skb);
|
|
new_len = slen + 3; /* enclosing quotes + null terminator */
|
|
if (new_len > avail) {
|
|
avail = audit_expand(ab, new_len);
|
|
if (!avail)
|
|
return;
|
|
}
|
|
ptr = skb_tail_pointer(skb);
|
|
*ptr++ = '"';
|
|
memcpy(ptr, string, slen);
|
|
ptr += slen;
|
|
*ptr++ = '"';
|
|
*ptr = 0;
|
|
skb_put(skb, slen + 2); /* don't include null terminator */
|
|
}
|
|
|
|
/**
|
|
* audit_string_contains_control - does a string need to be logged in hex
|
|
* @string: string to be checked
|
|
* @len: max length of the string to check
|
|
*/
|
|
bool audit_string_contains_control(const char *string, size_t len)
|
|
{
|
|
const unsigned char *p;
|
|
for (p = string; p < (const unsigned char *)string + len; p++) {
|
|
if (*p == '"' || *p < 0x21 || *p > 0x7e)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* audit_log_n_untrustedstring - log a string that may contain random characters
|
|
* @ab: audit_buffer
|
|
* @len: length of string (not including trailing null)
|
|
* @string: string to be logged
|
|
*
|
|
* This code will escape a string that is passed to it if the string
|
|
* contains a control character, unprintable character, double quote mark,
|
|
* or a space. Unescaped strings will start and end with a double quote mark.
|
|
* Strings that are escaped are printed in hex (2 digits per char).
|
|
*
|
|
* The caller specifies the number of characters in the string to log, which may
|
|
* or may not be the entire string.
|
|
*/
|
|
void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
|
|
size_t len)
|
|
{
|
|
if (audit_string_contains_control(string, len))
|
|
audit_log_n_hex(ab, string, len);
|
|
else
|
|
audit_log_n_string(ab, string, len);
|
|
}
|
|
|
|
/**
|
|
* audit_log_untrustedstring - log a string that may contain random characters
|
|
* @ab: audit_buffer
|
|
* @string: string to be logged
|
|
*
|
|
* Same as audit_log_n_untrustedstring(), except that strlen is used to
|
|
* determine string length.
|
|
*/
|
|
void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
|
|
{
|
|
audit_log_n_untrustedstring(ab, string, strlen(string));
|
|
}
|
|
|
|
/* This is a helper-function to print the escaped d_path */
|
|
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
|
|
const struct path *path)
|
|
{
|
|
char *p, *pathname;
|
|
|
|
if (prefix)
|
|
audit_log_format(ab, "%s", prefix);
|
|
|
|
/* We will allow 11 spaces for ' (deleted)' to be appended */
|
|
pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
|
|
if (!pathname) {
|
|
audit_log_format(ab, "\"<no_memory>\"");
|
|
return;
|
|
}
|
|
p = d_path(path, pathname, PATH_MAX+11);
|
|
if (IS_ERR(p)) { /* Should never happen since we send PATH_MAX */
|
|
/* FIXME: can we save some information here? */
|
|
audit_log_format(ab, "\"<too_long>\"");
|
|
} else
|
|
audit_log_untrustedstring(ab, p);
|
|
kfree(pathname);
|
|
}
|
|
|
|
void audit_log_session_info(struct audit_buffer *ab)
|
|
{
|
|
unsigned int sessionid = audit_get_sessionid(current);
|
|
uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
|
|
|
|
audit_log_format(ab, "auid=%u ses=%u", auid, sessionid);
|
|
}
|
|
|
|
void audit_log_key(struct audit_buffer *ab, char *key)
|
|
{
|
|
audit_log_format(ab, " key=");
|
|
if (key)
|
|
audit_log_untrustedstring(ab, key);
|
|
else
|
|
audit_log_format(ab, "(null)");
|
|
}
|
|
|
|
int audit_log_task_context(struct audit_buffer *ab)
|
|
{
|
|
char *ctx = NULL;
|
|
unsigned len;
|
|
int error;
|
|
u32 sid;
|
|
|
|
security_task_getsecid(current, &sid);
|
|
if (!sid)
|
|
return 0;
|
|
|
|
error = security_secid_to_secctx(sid, &ctx, &len);
|
|
if (error) {
|
|
if (error != -EINVAL)
|
|
goto error_path;
|
|
return 0;
|
|
}
|
|
|
|
audit_log_format(ab, " subj=%s", ctx);
|
|
security_release_secctx(ctx, len);
|
|
return 0;
|
|
|
|
error_path:
|
|
audit_panic("error in audit_log_task_context");
|
|
return error;
|
|
}
|
|
EXPORT_SYMBOL(audit_log_task_context);
|
|
|
|
void audit_log_d_path_exe(struct audit_buffer *ab,
|
|
struct mm_struct *mm)
|
|
{
|
|
struct file *exe_file;
|
|
|
|
if (!mm)
|
|
goto out_null;
|
|
|
|
exe_file = get_mm_exe_file(mm);
|
|
if (!exe_file)
|
|
goto out_null;
|
|
|
|
audit_log_d_path(ab, " exe=", &exe_file->f_path);
|
|
fput(exe_file);
|
|
return;
|
|
out_null:
|
|
audit_log_format(ab, " exe=(null)");
|
|
}
|
|
|
|
struct tty_struct *audit_get_tty(void)
|
|
{
|
|
struct tty_struct *tty = NULL;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(¤t->sighand->siglock, flags);
|
|
if (current->signal)
|
|
tty = tty_kref_get(current->signal->tty);
|
|
spin_unlock_irqrestore(¤t->sighand->siglock, flags);
|
|
return tty;
|
|
}
|
|
|
|
void audit_put_tty(struct tty_struct *tty)
|
|
{
|
|
tty_kref_put(tty);
|
|
}
|
|
|
|
void audit_log_task_info(struct audit_buffer *ab)
|
|
{
|
|
const struct cred *cred;
|
|
char comm[sizeof(current->comm)];
|
|
struct tty_struct *tty;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
cred = current_cred();
|
|
tty = audit_get_tty();
|
|
audit_log_format(ab,
|
|
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
|
|
" euid=%u suid=%u fsuid=%u"
|
|
" egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
|
|
task_ppid_nr(current),
|
|
task_tgid_nr(current),
|
|
from_kuid(&init_user_ns, audit_get_loginuid(current)),
|
|
from_kuid(&init_user_ns, cred->uid),
|
|
from_kgid(&init_user_ns, cred->gid),
|
|
from_kuid(&init_user_ns, cred->euid),
|
|
from_kuid(&init_user_ns, cred->suid),
|
|
from_kuid(&init_user_ns, cred->fsuid),
|
|
from_kgid(&init_user_ns, cred->egid),
|
|
from_kgid(&init_user_ns, cred->sgid),
|
|
from_kgid(&init_user_ns, cred->fsgid),
|
|
tty ? tty_name(tty) : "(none)",
|
|
audit_get_sessionid(current));
|
|
audit_put_tty(tty);
|
|
audit_log_format(ab, " comm=");
|
|
audit_log_untrustedstring(ab, get_task_comm(comm, current));
|
|
audit_log_d_path_exe(ab, current->mm);
|
|
audit_log_task_context(ab);
|
|
}
|
|
EXPORT_SYMBOL(audit_log_task_info);
|
|
|
|
/**
|
|
* audit_log_path_denied - report a path restriction denial
|
|
* @type: audit message type (AUDIT_ANOM_LINK, AUDIT_ANOM_CREAT, etc)
|
|
* @operation: specific operation name
|
|
*/
|
|
void audit_log_path_denied(int type, const char *operation)
|
|
{
|
|
struct audit_buffer *ab;
|
|
|
|
if (!audit_enabled || audit_dummy_context())
|
|
return;
|
|
|
|
/* Generate log with subject, operation, outcome. */
|
|
ab = audit_log_start(audit_context(), GFP_KERNEL, type);
|
|
if (!ab)
|
|
return;
|
|
audit_log_format(ab, "op=%s", operation);
|
|
audit_log_task_info(ab);
|
|
audit_log_format(ab, " res=0");
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
/* global counter which is incremented every time something logs in */
|
|
static atomic_t session_id = ATOMIC_INIT(0);
|
|
|
|
static int audit_set_loginuid_perm(kuid_t loginuid)
|
|
{
|
|
/* if we are unset, we don't need privs */
|
|
if (!audit_loginuid_set(current))
|
|
return 0;
|
|
/* if AUDIT_FEATURE_LOGINUID_IMMUTABLE means never ever allow a change*/
|
|
if (is_audit_feature_set(AUDIT_FEATURE_LOGINUID_IMMUTABLE))
|
|
return -EPERM;
|
|
/* it is set, you need permission */
|
|
if (!capable(CAP_AUDIT_CONTROL))
|
|
return -EPERM;
|
|
/* reject if this is not an unset and we don't allow that */
|
|
if (is_audit_feature_set(AUDIT_FEATURE_ONLY_UNSET_LOGINUID)
|
|
&& uid_valid(loginuid))
|
|
return -EPERM;
|
|
return 0;
|
|
}
|
|
|
|
static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
|
|
unsigned int oldsessionid,
|
|
unsigned int sessionid, int rc)
|
|
{
|
|
struct audit_buffer *ab;
|
|
uid_t uid, oldloginuid, loginuid;
|
|
struct tty_struct *tty;
|
|
|
|
if (!audit_enabled)
|
|
return;
|
|
|
|
ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_LOGIN);
|
|
if (!ab)
|
|
return;
|
|
|
|
uid = from_kuid(&init_user_ns, task_uid(current));
|
|
oldloginuid = from_kuid(&init_user_ns, koldloginuid);
|
|
loginuid = from_kuid(&init_user_ns, kloginuid),
|
|
tty = audit_get_tty();
|
|
|
|
audit_log_format(ab, "pid=%d uid=%u", task_tgid_nr(current), uid);
|
|
audit_log_task_context(ab);
|
|
audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
|
|
oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
|
|
oldsessionid, sessionid, !rc);
|
|
audit_put_tty(tty);
|
|
audit_log_end(ab);
|
|
}
|
|
|
|
/**
|
|
* audit_set_loginuid - set current task's loginuid
|
|
* @loginuid: loginuid value
|
|
*
|
|
* Returns 0.
|
|
*
|
|
* Called (set) from fs/proc/base.c::proc_loginuid_write().
|
|
*/
|
|
int audit_set_loginuid(kuid_t loginuid)
|
|
{
|
|
unsigned int oldsessionid, sessionid = AUDIT_SID_UNSET;
|
|
kuid_t oldloginuid;
|
|
int rc;
|
|
|
|
oldloginuid = audit_get_loginuid(current);
|
|
oldsessionid = audit_get_sessionid(current);
|
|
|
|
rc = audit_set_loginuid_perm(loginuid);
|
|
if (rc)
|
|
goto out;
|
|
|
|
/* are we setting or clearing? */
|
|
if (uid_valid(loginuid)) {
|
|
sessionid = (unsigned int)atomic_inc_return(&session_id);
|
|
if (unlikely(sessionid == AUDIT_SID_UNSET))
|
|
sessionid = (unsigned int)atomic_inc_return(&session_id);
|
|
}
|
|
|
|
current->sessionid = sessionid;
|
|
current->loginuid = loginuid;
|
|
out:
|
|
audit_log_set_loginuid(oldloginuid, loginuid, oldsessionid, sessionid, rc);
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* audit_signal_info - record signal info for shutting down audit subsystem
|
|
* @sig: signal value
|
|
* @t: task being signaled
|
|
*
|
|
* If the audit subsystem is being terminated, record the task (pid)
|
|
* and uid that is doing that.
|
|
*/
|
|
int audit_signal_info(int sig, struct task_struct *t)
|
|
{
|
|
kuid_t uid = current_uid(), auid;
|
|
|
|
if (auditd_test_task(t) &&
|
|
(sig == SIGTERM || sig == SIGHUP ||
|
|
sig == SIGUSR1 || sig == SIGUSR2)) {
|
|
audit_sig_pid = task_tgid_nr(current);
|
|
auid = audit_get_loginuid(current);
|
|
if (uid_valid(auid))
|
|
audit_sig_uid = auid;
|
|
else
|
|
audit_sig_uid = uid;
|
|
security_task_getsecid(current, &audit_sig_sid);
|
|
}
|
|
|
|
return audit_signal_info_syscall(t);
|
|
}
|
|
|
|
/**
|
|
* audit_log_end - end one audit record
|
|
* @ab: the audit_buffer
|
|
*
|
|
* We can not do a netlink send inside an irq context because it blocks (last
|
|
* arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed on a
|
|
* queue and a tasklet is scheduled to remove them from the queue outside the
|
|
* irq context. May be called in any context.
|
|
*/
|
|
void audit_log_end(struct audit_buffer *ab)
|
|
{
|
|
struct sk_buff *skb;
|
|
struct nlmsghdr *nlh;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
if (audit_rate_check()) {
|
|
skb = ab->skb;
|
|
ab->skb = NULL;
|
|
|
|
/* setup the netlink header, see the comments in
|
|
* kauditd_send_multicast_skb() for length quirks */
|
|
nlh = nlmsg_hdr(skb);
|
|
nlh->nlmsg_len = skb->len - NLMSG_HDRLEN;
|
|
|
|
/* queue the netlink packet and poke the kauditd thread */
|
|
skb_queue_tail(&audit_queue, skb);
|
|
wake_up_interruptible(&kauditd_wait);
|
|
} else
|
|
audit_log_lost("rate limit exceeded");
|
|
|
|
audit_buffer_free(ab);
|
|
}
|
|
|
|
/**
|
|
* audit_log - Log an audit record
|
|
* @ctx: audit context
|
|
* @gfp_mask: type of allocation
|
|
* @type: audit message type
|
|
* @fmt: format string to use
|
|
* @...: variable parameters matching the format string
|
|
*
|
|
* This is a convenience function that calls audit_log_start,
|
|
* audit_log_vformat, and audit_log_end. It may be called
|
|
* in any context.
|
|
*/
|
|
void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
|
|
const char *fmt, ...)
|
|
{
|
|
struct audit_buffer *ab;
|
|
va_list args;
|
|
|
|
ab = audit_log_start(ctx, gfp_mask, type);
|
|
if (ab) {
|
|
va_start(args, fmt);
|
|
audit_log_vformat(ab, fmt, args);
|
|
va_end(args);
|
|
audit_log_end(ab);
|
|
}
|
|
}
|
|
|
|
EXPORT_SYMBOL(audit_log_start);
|
|
EXPORT_SYMBOL(audit_log_end);
|
|
EXPORT_SYMBOL(audit_log_format);
|
|
EXPORT_SYMBOL(audit_log);
|