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2427 lines
64 KiB
2427 lines
64 KiB
// 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 <[email protected]> |
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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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|
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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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|
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#include <linux/audit.h> |
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|
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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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|
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#include "audit.h" |
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|
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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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|
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u32 audit_enabled = AUDIT_OFF; |
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bool audit_ever_enabled = !!AUDIT_OFF; |
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|
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EXPORT_SYMBOL_GPL(audit_enabled); |
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|
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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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|
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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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|
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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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/** |
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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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/** |
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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|
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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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/** |
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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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|
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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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|
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if (ac_old) |
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call_rcu(&ac_old->rcu, auditd_conn_free); |
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|
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return 0; |
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} |
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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 |
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* so write it via printk so the information isn't completely lost. |
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*/ |
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static void kauditd_printk_skb(struct sk_buff *skb) |
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{ |
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struct nlmsghdr *nlh = nlmsg_hdr(skb); |
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char *data = nlmsg_data(nlh); |
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|
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if (nlh->nlmsg_type != AUDIT_EOE && printk_ratelimit()) |
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pr_notice("type=%d %s\n", nlh->nlmsg_type, data); |
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} |
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|
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/** |
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* kauditd_rehold_skb - Handle a audit record send failure in the hold queue |
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* @skb: audit record |
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* |
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* Description: |
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* This should only be used by the kauditd_thread when it fails to flush the |
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* hold queue. |
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*/ |
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static void kauditd_rehold_skb(struct sk_buff *skb) |
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{ |
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/* put the record back in the queue at the same place */ |
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skb_queue_head(&audit_hold_queue, skb); |
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} |
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|
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/** |
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* kauditd_hold_skb - Queue an audit record, waiting for auditd |
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* @skb: audit record |
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* |
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* Description: |
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* Queue the audit record, waiting for an instance of auditd. When this |
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* function is called we haven't given up yet on sending the record, but things |
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* are not looking good. The first thing we want to do is try to write the |
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* record via printk and then see if we want to try and hold on to the record |
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* and queue it, if we have room. If we want to hold on to the record, but we |
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* don't have room, record a record lost message. |
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*/ |
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static void kauditd_hold_skb(struct sk_buff *skb) |
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{ |
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/* at this point it is uncertain if we will ever send this to auditd so |
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* try to send the message via printk before we go any further */ |
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kauditd_printk_skb(skb); |
|
|
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/* can we just silently drop the message? */ |
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if (!audit_default) { |
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kfree_skb(skb); |
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return; |
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} |
|
|
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/* if we have room, queue the message */ |
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if (!audit_backlog_limit || |
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skb_queue_len(&audit_hold_queue) < audit_backlog_limit) { |
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skb_queue_tail(&audit_hold_queue, skb); |
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return; |
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} |
|
|
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/* we have no other options - drop the message */ |
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audit_log_lost("kauditd hold queue overflow"); |
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kfree_skb(skb); |
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} |
|
|
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/** |
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* 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_subj(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_subj(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 kthread 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);
|
|
|