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841 lines
23 KiB
841 lines
23 KiB
/* 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 2003-2004 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Written by Rickard E. (Rik) Faith <faith@redhat.com>
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*
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* Goals: 1) Integrate fully with SELinux.
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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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* Example user-space utilities: http://people.redhat.com/sgrubb/audit/
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*/
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#include <linux/init.h>
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#include <asm/atomic.h>
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#include <asm/types.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/audit.h>
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#include <net/sock.h>
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#include <linux/skbuff.h>
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#include <linux/netlink.h>
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/* No auditing will take place until audit_initialized != 0.
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* (Initialization happens after skb_init is called.) */
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static int audit_initialized;
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/* No syscall auditing will take place unless audit_enabled != 0. */
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int audit_enabled;
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/* Default state when kernel boots without any parameters. */
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static int audit_default;
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/* If auditing cannot proceed, audit_failure selects what happens. */
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static int audit_failure = AUDIT_FAIL_PRINTK;
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/* If audit records are to be written to the netlink socket, audit_pid
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* contains the (non-zero) pid. */
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int audit_pid;
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/* If audit_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 int audit_rate_limit;
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/* Number of outstanding audit_buffers allowed. */
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static int audit_backlog_limit = 64;
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static atomic_t audit_backlog = ATOMIC_INIT(0);
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/* The identity of the user shutting down the audit system. */
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uid_t audit_sig_uid = -1;
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pid_t audit_sig_pid = -1;
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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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/* The netlink socket. */
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static struct sock *audit_sock;
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/* There are two lists of audit buffers. The txlist contains audit
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* buffers that cannot be sent immediately to the netlink device because
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* we are in an irq context (these are sent later in a tasklet).
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*
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* The second list is a list of pre-allocated audit buffers (if more
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* than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
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* being placed on the freelist). */
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static DEFINE_SPINLOCK(audit_txlist_lock);
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static DEFINE_SPINLOCK(audit_freelist_lock);
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static int audit_freelist_count = 0;
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static LIST_HEAD(audit_txlist);
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static LIST_HEAD(audit_freelist);
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/* There are three lists of rules -- one to search at task creation
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* time, one to search at syscall entry time, and another to search at
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* syscall exit time. */
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static LIST_HEAD(audit_tsklist);
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static LIST_HEAD(audit_entlist);
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static LIST_HEAD(audit_extlist);
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/* The netlink socket is only to be read by 1 CPU, which lets us assume
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* that list additions and deletions never happen simultaneously in
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* auditsc.c */
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static DECLARE_MUTEX(audit_netlink_sem);
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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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/* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the
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* audit_freelist. Doing so eliminates many kmalloc/kfree calls. */
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#define AUDIT_MAXFREE (2*NR_CPUS)
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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 list_head list;
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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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};
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static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
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{
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struct nlmsghdr *nlh = (struct nlmsghdr *)ab->skb->data;
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nlh->nlmsg_pid = pid;
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}
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struct audit_entry {
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struct list_head list;
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struct audit_rule rule;
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};
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static void audit_log_end_irq(struct audit_buffer *ab);
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static void audit_log_end_fast(struct audit_buffer *ab);
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static void audit_panic(const char *message)
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{
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switch (audit_failure)
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{
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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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printk(KERN_ERR "audit: %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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/* Emit at least 1 message per second, even if audit_rate_check is
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* throttling. */
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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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printk(KERN_WARNING
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"audit: audit_lost=%d audit_backlog=%d"
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" audit_rate_limit=%d audit_backlog_limit=%d\n",
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atomic_read(&audit_lost),
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atomic_read(&audit_backlog),
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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_set_rate_limit(int limit, uid_t loginuid)
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{
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int old = audit_rate_limit;
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audit_rate_limit = limit;
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audit_log(NULL, AUDIT_CONFIG_CHANGE,
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"audit_rate_limit=%d old=%d by auid %u",
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audit_rate_limit, old, loginuid);
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return old;
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}
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static int audit_set_backlog_limit(int limit, uid_t loginuid)
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{
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int old = audit_backlog_limit;
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audit_backlog_limit = limit;
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audit_log(NULL, AUDIT_CONFIG_CHANGE,
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"audit_backlog_limit=%d old=%d by auid %u",
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audit_backlog_limit, old, loginuid);
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return old;
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}
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static int audit_set_enabled(int state, uid_t loginuid)
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{
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int old = audit_enabled;
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if (state != 0 && state != 1)
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return -EINVAL;
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audit_enabled = state;
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audit_log(NULL, AUDIT_CONFIG_CHANGE,
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"audit_enabled=%d old=%d by auid %u",
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audit_enabled, old, loginuid);
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return old;
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}
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static int audit_set_failure(int state, uid_t loginuid)
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{
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int old = audit_failure;
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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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audit_failure = state;
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audit_log(NULL, AUDIT_CONFIG_CHANGE,
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"audit_failure=%d old=%d by auid %u",
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audit_failure, old, loginuid);
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return old;
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}
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void audit_send_reply(int pid, int seq, int type, int done, int multi,
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void *payload, int size)
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{
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struct sk_buff *skb;
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struct nlmsghdr *nlh;
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int len = NLMSG_SPACE(size);
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void *data;
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int flags = multi ? NLM_F_MULTI : 0;
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int t = done ? NLMSG_DONE : type;
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skb = alloc_skb(len, GFP_KERNEL);
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if (!skb)
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goto nlmsg_failure;
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nlh = NLMSG_PUT(skb, pid, seq, t, len - sizeof(*nlh));
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nlh->nlmsg_flags = flags;
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data = NLMSG_DATA(nlh);
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memcpy(data, payload, size);
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netlink_unicast(audit_sock, skb, pid, MSG_DONTWAIT);
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return;
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nlmsg_failure: /* Used by NLMSG_PUT */
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if (skb)
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kfree_skb(skb);
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}
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/*
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* Check for appropriate CAP_AUDIT_ capabilities on incoming audit
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* control messages.
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*/
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static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type)
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{
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int err = 0;
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switch (msg_type) {
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case AUDIT_GET:
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case AUDIT_LIST:
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case AUDIT_SET:
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case AUDIT_ADD:
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case AUDIT_DEL:
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case AUDIT_SIGNAL_INFO:
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if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL))
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err = -EPERM;
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break;
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case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
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if (!cap_raised(eff_cap, CAP_AUDIT_WRITE))
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err = -EPERM;
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break;
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default: /* bad msg */
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err = -EINVAL;
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}
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return err;
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}
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static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
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{
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u32 uid, pid, seq;
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void *data;
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struct audit_status *status_get, status_set;
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int err;
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struct audit_buffer *ab;
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u16 msg_type = nlh->nlmsg_type;
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uid_t loginuid; /* loginuid of sender */
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struct audit_sig_info sig_data;
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err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type);
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if (err)
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return err;
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pid = NETLINK_CREDS(skb)->pid;
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uid = NETLINK_CREDS(skb)->uid;
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loginuid = NETLINK_CB(skb).loginuid;
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seq = nlh->nlmsg_seq;
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data = NLMSG_DATA(nlh);
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switch (msg_type) {
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case AUDIT_GET:
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status_set.enabled = audit_enabled;
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status_set.failure = audit_failure;
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status_set.pid = audit_pid;
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status_set.rate_limit = audit_rate_limit;
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status_set.backlog_limit = audit_backlog_limit;
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status_set.lost = atomic_read(&audit_lost);
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status_set.backlog = atomic_read(&audit_backlog);
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audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
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&status_set, sizeof(status_set));
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break;
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case AUDIT_SET:
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if (nlh->nlmsg_len < sizeof(struct audit_status))
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return -EINVAL;
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status_get = (struct audit_status *)data;
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if (status_get->mask & AUDIT_STATUS_ENABLED) {
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err = audit_set_enabled(status_get->enabled, loginuid);
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if (err < 0) return err;
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}
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if (status_get->mask & AUDIT_STATUS_FAILURE) {
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err = audit_set_failure(status_get->failure, loginuid);
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if (err < 0) return err;
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}
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if (status_get->mask & AUDIT_STATUS_PID) {
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int old = audit_pid;
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audit_pid = status_get->pid;
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audit_log(NULL, AUDIT_CONFIG_CHANGE,
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"audit_pid=%d old=%d by auid %u",
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audit_pid, old, loginuid);
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}
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if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
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audit_set_rate_limit(status_get->rate_limit, loginuid);
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if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
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audit_set_backlog_limit(status_get->backlog_limit,
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loginuid);
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break;
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case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
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ab = audit_log_start(NULL, msg_type);
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if (!ab)
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break; /* audit_panic has been called */
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audit_log_format(ab,
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"user pid=%d uid=%d length=%d loginuid=%u"
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" msg='%.1024s'",
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pid, uid,
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(int)(nlh->nlmsg_len
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- ((char *)data - (char *)nlh)),
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loginuid, (char *)data);
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audit_set_pid(ab, pid);
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audit_log_end(ab);
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break;
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case AUDIT_ADD:
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case AUDIT_DEL:
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if (nlh->nlmsg_len < sizeof(struct audit_rule))
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return -EINVAL;
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/* fallthrough */
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case AUDIT_LIST:
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err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
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uid, seq, data, loginuid);
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break;
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case AUDIT_SIGNAL_INFO:
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sig_data.uid = audit_sig_uid;
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sig_data.pid = audit_sig_pid;
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audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
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0, 0, &sig_data, sizeof(sig_data));
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break;
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default:
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err = -EINVAL;
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break;
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}
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return err < 0 ? err : 0;
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}
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/* Get message from skb (based on rtnetlink_rcv_skb). Each message is
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* processed by audit_receive_msg. Malformed skbs with wrong length are
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* discarded silently. */
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static void audit_receive_skb(struct sk_buff *skb)
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{
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int err;
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struct nlmsghdr *nlh;
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u32 rlen;
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while (skb->len >= NLMSG_SPACE(0)) {
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nlh = (struct nlmsghdr *)skb->data;
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if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
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return;
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rlen = NLMSG_ALIGN(nlh->nlmsg_len);
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if (rlen > skb->len)
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rlen = skb->len;
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if ((err = audit_receive_msg(skb, nlh))) {
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netlink_ack(skb, nlh, err);
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} else if (nlh->nlmsg_flags & NLM_F_ACK)
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netlink_ack(skb, nlh, 0);
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skb_pull(skb, rlen);
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}
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}
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/* Receive messages from netlink socket. */
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static void audit_receive(struct sock *sk, int length)
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{
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struct sk_buff *skb;
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unsigned int qlen;
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down(&audit_netlink_sem);
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for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
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skb = skb_dequeue(&sk->sk_receive_queue);
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audit_receive_skb(skb);
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kfree_skb(skb);
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}
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up(&audit_netlink_sem);
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}
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/* Grab skbuff from the audit_buffer and send to user space. */
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static inline int audit_log_drain(struct audit_buffer *ab)
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{
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struct sk_buff *skb = ab->skb;
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if (skb) {
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int retval = 0;
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if (audit_pid) {
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struct nlmsghdr *nlh = (struct nlmsghdr *)skb->data;
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nlh->nlmsg_len = skb->len - NLMSG_SPACE(0);
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skb_get(skb); /* because netlink_* frees */
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retval = netlink_unicast(audit_sock, skb, audit_pid,
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MSG_DONTWAIT);
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}
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if (retval == -EAGAIN &&
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(atomic_read(&audit_backlog)) < audit_backlog_limit) {
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audit_log_end_irq(ab);
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return 1;
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}
|
|
if (retval < 0) {
|
|
if (retval == -ECONNREFUSED) {
|
|
printk(KERN_ERR
|
|
"audit: *NO* daemon at audit_pid=%d\n",
|
|
audit_pid);
|
|
audit_pid = 0;
|
|
} else
|
|
audit_log_lost("netlink socket too busy");
|
|
}
|
|
if (!audit_pid) { /* No daemon */
|
|
int offset = NLMSG_SPACE(0);
|
|
int len = skb->len - offset;
|
|
skb->data[offset + len] = '\0';
|
|
printk(KERN_ERR "%s\n", skb->data + offset);
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* Initialize audit support at boot time. */
|
|
static int __init audit_init(void)
|
|
{
|
|
printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
|
|
audit_default ? "enabled" : "disabled");
|
|
audit_sock = netlink_kernel_create(NETLINK_AUDIT, audit_receive);
|
|
if (!audit_sock)
|
|
audit_panic("cannot initialize netlink socket");
|
|
|
|
audit_initialized = 1;
|
|
audit_enabled = audit_default;
|
|
audit_log(NULL, AUDIT_KERNEL, "initialized");
|
|
return 0;
|
|
}
|
|
__initcall(audit_init);
|
|
|
|
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
|
|
static int __init audit_enable(char *str)
|
|
{
|
|
audit_default = !!simple_strtol(str, NULL, 0);
|
|
printk(KERN_INFO "audit: %s%s\n",
|
|
audit_default ? "enabled" : "disabled",
|
|
audit_initialized ? "" : " (after initialization)");
|
|
if (audit_initialized)
|
|
audit_enabled = audit_default;
|
|
return 0;
|
|
}
|
|
|
|
__setup("audit=", audit_enable);
|
|
|
|
static void audit_buffer_free(struct audit_buffer *ab)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!ab)
|
|
return;
|
|
|
|
if (ab->skb)
|
|
kfree_skb(ab->skb);
|
|
atomic_dec(&audit_backlog);
|
|
spin_lock_irqsave(&audit_freelist_lock, flags);
|
|
if (++audit_freelist_count > AUDIT_MAXFREE)
|
|
kfree(ab);
|
|
else
|
|
list_add(&ab->list, &audit_freelist);
|
|
spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
|
}
|
|
|
|
static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
|
|
int gfp_mask, int type)
|
|
{
|
|
unsigned long flags;
|
|
struct audit_buffer *ab = NULL;
|
|
struct nlmsghdr *nlh;
|
|
|
|
spin_lock_irqsave(&audit_freelist_lock, flags);
|
|
if (!list_empty(&audit_freelist)) {
|
|
ab = list_entry(audit_freelist.next,
|
|
struct audit_buffer, list);
|
|
list_del(&ab->list);
|
|
--audit_freelist_count;
|
|
}
|
|
spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
|
|
|
if (!ab) {
|
|
ab = kmalloc(sizeof(*ab), gfp_mask);
|
|
if (!ab)
|
|
goto err;
|
|
}
|
|
atomic_inc(&audit_backlog);
|
|
|
|
ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask);
|
|
if (!ab->skb)
|
|
goto err;
|
|
|
|
ab->ctx = ctx;
|
|
nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0));
|
|
nlh->nlmsg_type = type;
|
|
nlh->nlmsg_flags = 0;
|
|
nlh->nlmsg_pid = 0;
|
|
nlh->nlmsg_seq = 0;
|
|
return ab;
|
|
err:
|
|
audit_buffer_free(ab);
|
|
return NULL;
|
|
}
|
|
|
|
/* 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 tsk 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, tsk
|
|
* should be NULL. */
|
|
struct audit_buffer *audit_log_start(struct audit_context *ctx, int type)
|
|
{
|
|
struct audit_buffer *ab = NULL;
|
|
struct timespec t;
|
|
unsigned int serial;
|
|
|
|
if (!audit_initialized)
|
|
return NULL;
|
|
|
|
if (audit_backlog_limit
|
|
&& atomic_read(&audit_backlog) > audit_backlog_limit) {
|
|
if (audit_rate_check())
|
|
printk(KERN_WARNING
|
|
"audit: audit_backlog=%d > "
|
|
"audit_backlog_limit=%d\n",
|
|
atomic_read(&audit_backlog),
|
|
audit_backlog_limit);
|
|
audit_log_lost("backlog limit exceeded");
|
|
return NULL;
|
|
}
|
|
|
|
ab = audit_buffer_alloc(ctx, GFP_ATOMIC, type);
|
|
if (!ab) {
|
|
audit_log_lost("out of memory in audit_log_start");
|
|
return NULL;
|
|
}
|
|
|
|
if (!audit_get_stamp(ab->ctx, &t, &serial)) {
|
|
t = CURRENT_TIME;
|
|
serial = 0;
|
|
}
|
|
|
|
audit_log_format(ab, "audit(%lu.%03lu:%u): ",
|
|
t.tv_sec, t.tv_nsec/1000000, serial);
|
|
return ab;
|
|
}
|
|
|
|
/**
|
|
* audit_expand - expand skb in the audit buffer
|
|
* @ab: audit_buffer
|
|
*
|
|
* 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 ret = pskb_expand_head(skb, skb_headroom(skb), extra,
|
|
GFP_ATOMIC);
|
|
if (ret < 0) {
|
|
audit_log_lost("out of memory in audit_expand");
|
|
return 0;
|
|
}
|
|
return skb_tailroom(skb);
|
|
}
|
|
|
|
/* 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, 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;
|
|
len = vsnprintf(skb->tail, avail, fmt, args2);
|
|
}
|
|
skb_put(skb, (len < avail) ? len : avail);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
/* Format a message into the audit buffer. 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);
|
|
}
|
|
|
|
void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf, size_t len)
|
|
{
|
|
int i;
|
|
|
|
for (i=0; i<len; i++)
|
|
audit_log_format(ab, "%02x", buf[i]);
|
|
}
|
|
|
|
void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
|
|
{
|
|
const unsigned char *p = string;
|
|
|
|
while (*p) {
|
|
if (*p == '"' || *p == ' ' || *p < 0x20 || *p > 0x7f) {
|
|
audit_log_hex(ab, string, strlen(string));
|
|
return;
|
|
}
|
|
p++;
|
|
}
|
|
audit_log_format(ab, "\"%s\"", string);
|
|
}
|
|
|
|
|
|
/* This is a helper-function to print the d_path without using a static
|
|
* buffer or allocating another buffer in addition to the one in
|
|
* audit_buffer. */
|
|
void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
|
|
struct dentry *dentry, struct vfsmount *vfsmnt)
|
|
{
|
|
char *p;
|
|
struct sk_buff *skb = ab->skb;
|
|
int len, avail;
|
|
|
|
if (prefix)
|
|
audit_log_format(ab, " %s", prefix);
|
|
|
|
avail = skb_tailroom(skb);
|
|
p = d_path(dentry, vfsmnt, skb->tail, avail);
|
|
if (IS_ERR(p)) {
|
|
/* FIXME: can we save some information here? */
|
|
audit_log_format(ab, "<toolong>");
|
|
} else {
|
|
/* path isn't at start of buffer */
|
|
len = ((char *)skb->tail + avail - 1) - p;
|
|
memmove(skb->tail, p, len);
|
|
skb_put(skb, len);
|
|
}
|
|
}
|
|
|
|
/* Remove queued messages from the audit_txlist and send them to user space. */
|
|
static void audit_tasklet_handler(unsigned long arg)
|
|
{
|
|
LIST_HEAD(list);
|
|
struct audit_buffer *ab;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&audit_txlist_lock, flags);
|
|
list_splice_init(&audit_txlist, &list);
|
|
spin_unlock_irqrestore(&audit_txlist_lock, flags);
|
|
|
|
while (!list_empty(&list)) {
|
|
ab = list_entry(list.next, struct audit_buffer, list);
|
|
list_del(&ab->list);
|
|
audit_log_end_fast(ab);
|
|
}
|
|
}
|
|
|
|
static DECLARE_TASKLET(audit_tasklet, audit_tasklet_handler, 0);
|
|
|
|
/* The netlink_* functions cannot be called inside an irq context, so
|
|
* the audit buffer is places on a queue and a tasklet is scheduled to
|
|
* remove them from the queue outside the irq context. May be called in
|
|
* any context. */
|
|
static void audit_log_end_irq(struct audit_buffer *ab)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (!ab)
|
|
return;
|
|
spin_lock_irqsave(&audit_txlist_lock, flags);
|
|
list_add_tail(&ab->list, &audit_txlist);
|
|
spin_unlock_irqrestore(&audit_txlist_lock, flags);
|
|
|
|
tasklet_schedule(&audit_tasklet);
|
|
}
|
|
|
|
/* Send the message in the audit buffer directly to user space. May not
|
|
* be called in an irq context. */
|
|
static void audit_log_end_fast(struct audit_buffer *ab)
|
|
{
|
|
BUG_ON(in_irq());
|
|
if (!ab)
|
|
return;
|
|
if (!audit_rate_check()) {
|
|
audit_log_lost("rate limit exceeded");
|
|
} else {
|
|
if (audit_log_drain(ab))
|
|
return;
|
|
}
|
|
audit_buffer_free(ab);
|
|
}
|
|
|
|
/* Send or queue the message in the audit buffer, depending on the
|
|
* current context. (A convenience function that may be called in any
|
|
* context.) */
|
|
void audit_log_end(struct audit_buffer *ab)
|
|
{
|
|
if (in_irq())
|
|
audit_log_end_irq(ab);
|
|
else
|
|
audit_log_end_fast(ab);
|
|
}
|
|
|
|
/* Log an audit record. 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, int type, const char *fmt, ...)
|
|
{
|
|
struct audit_buffer *ab;
|
|
va_list args;
|
|
|
|
ab = audit_log_start(ctx, type);
|
|
if (ab) {
|
|
va_start(args, fmt);
|
|
audit_log_vformat(ab, fmt, args);
|
|
va_end(args);
|
|
audit_log_end(ab);
|
|
}
|
|
}
|
|
|