| 1 | |
| 2 | * Gateway between the kernel (e.g., selinux) and the user-space audit daemon.
|
| 3 | * System-call specific features have moved to auditsc.c
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| 4 | *
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| 5 | * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina.
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| 6 | * All Rights Reserved.
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| 7 | *
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| 8 | * This program is free software; you can redistribute it and/or modify
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| 9 | * it under the terms of the GNU General Public License as published by
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| 10 | * the Free Software Foundation; either version 2 of the License, or
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| 11 | * (at your option) any later version.
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| 12 | *
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| 13 | * This program is distributed in the hope that it will be useful,
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| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 16 | * GNU General Public License for more details.
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| 17 | *
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| 18 | * You should have received a copy of the GNU General Public License
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| 19 | * along with this program; if not, write to the Free Software
|
| 20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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| 21 | *
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| 22 | * Written by Rickard E. (Rik) Faith <[email protected]>
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| 23 | *
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| 24 | * Goals: 1) Integrate fully with SELinux.
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| 25 | * 2) Minimal run-time overhead:
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| 26 | * a) Minimal when syscall auditing is disabled (audit_enable=0).
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| 27 | * b) Small when syscall auditing is enabled and no audit record
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| 28 | * is generated (defer as much work as possible to record
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| 29 | * generation time):
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| 30 | * i) context is allocated,
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| 31 | * ii) names from getname are stored without a copy, and
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| 32 | * iii) inode information stored from path_lookup.
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| 33 | * 3) Ability to disable syscall auditing at boot time (audit=0).
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| 34 | * 4) Usable by other parts of the kernel (if audit_log* is called,
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| 35 | * then a syscall record will be generated automatically for the
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| 36 | * current syscall).
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| 37 | * 5) Netlink interface to user-space.
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| 38 | * 6) Support low-overhead kernel-based filtering to minimize the
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| 39 | * information that must be passed to user-space.
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| 40 | *
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| 41 | * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
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| 42 |
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| 43 |
|
| 44 | #include <linux/init.h>
|
| 45 | #include <asm/types.h>
|
| 46 | #include <asm/atomic.h>
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| 47 | #include <linux/mm.h>
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| 48 | #include <linux/module.h>
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| 49 | #include <linux/err.h>
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| 50 | #include <linux/kthread.h>
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| 51 |
|
| 52 | #include <linux/audit.h>
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| 53 |
|
| 54 | #include <net/sock.h>
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| 55 | #include <net/netlink.h>
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| 56 | #include <linux/skbuff.h>
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| 57 | #include <linux/netlink.h>
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| 58 | #include <linux/selinux.h>
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| 59 | #include <linux/inotify.h>
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| 60 | #include <linux/freezer.h>
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| 61 | #include <linux/tty.h>
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| 62 |
|
| 63 | #include "audit.h"
|
| 64 |
|
| 65 | |
| 66 | * (Initialization happens after skb_init is called.)
|
| 67 | static int audit_initialized;
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| 68 |
|
| 69 | |
| 70 | * 1 - auditing enabled
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| 71 | * 2 - auditing enabled and configuration is locked/unchangeable.
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| 72 | int audit_enabled;
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| 73 |
|
| 74 |
|
| 75 | static int audit_default;
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| 76 |
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| 77 |
|
| 78 | static int audit_failure = AUDIT_FAIL_PRINTK;
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| 79 |
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| 80 | |
| 81 | * contains the (non-zero) pid.
|
| 82 | int audit_pid;
|
| 83 |
|
| 84 | |
| 85 | * to that number per second. This prevents DoS attacks, but results in
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| 86 | * audit records being dropped.
|
| 87 | static int audit_rate_limit;
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| 88 |
|
| 89 |
|
| 90 | static int audit_backlog_limit = 64;
|
| 91 | static int audit_backlog_wait_time = 60 * HZ;
|
| 92 | static int audit_backlog_wait_overflow = 0;
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| 93 |
|
| 94 |
|
| 95 | uid_t audit_sig_uid = -1;
|
| 96 | pid_t audit_sig_pid = -1;
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| 97 | u32 audit_sig_sid = 0;
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| 98 |
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| 99 | |
| 100 | 0) [suppressed in audit_alloc]
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| 101 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
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| 102 | 2) out of memory in audit_log_move [alloc_skb]
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| 103 | 3) suppressed due to audit_rate_limit
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| 104 | 4) suppressed due to audit_backlog_limit
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| 105 |
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| 106 | static atomic_t audit_lost = ATOMIC_INIT(0);
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| 107 |
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| 108 |
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| 109 | static struct sock *audit_sock;
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| 110 |
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| 111 |
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| 112 | struct inotify_handle *audit_ih;
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| 113 |
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| 114 |
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| 115 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
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| 116 |
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| 117 | |
| 118 | * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
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| 119 | * being placed on the freelist).
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| 120 | static DEFINE_SPINLOCK(audit_freelist_lock);
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| 121 | static int audit_freelist_count;
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| 122 | static LIST_HEAD(audit_freelist);
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| 123 |
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| 124 | static struct sk_buff_head audit_skb_queue;
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| 125 | static struct task_struct *kauditd_task;
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| 126 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
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| 127 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
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| 128 |
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| 129 |
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| 130 | static DEFINE_MUTEX(audit_cmd_mutex);
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| 131 |
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| 132 | |
| 133 | * audit records. Since printk uses a 1024 byte buffer, this buffer
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| 134 | * should be at least that large.
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| 135 | #define AUDIT_BUFSIZ 1024
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| 136 |
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| 137 | |
| 138 | * audit_freelist. Doing so eliminates many kmalloc/kfree calls.
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| 139 | #define AUDIT_MAXFREE (2*NR_CPUS)
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| 140 |
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| 141 | |
| 142 | * locks briefly to get the record off the freelist or to allocate the
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| 143 | * buffer, and locks briefly to send the buffer to the netlink layer or
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| 144 | * to place it on a transmit queue. Multiple audit_buffers can be in
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| 145 | * use simultaneously.
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| 146 | struct audit_buffer {
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| 147 | struct list_head list;
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| 148 | struct sk_buff *skb;
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| 149 | struct audit_context *ctx;
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| 150 | gfp_t gfp_mask;
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| 151 | };
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| 152 |
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| 153 | static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
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| 154 | {
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| 155 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
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| 156 | nlh->nlmsg_pid = pid;
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| 157 | }
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| 158 |
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| 159 | void audit_panic(const char *message)
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| 160 | {
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| 161 | switch (audit_failure)
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| 162 | {
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| 163 | case AUDIT_FAIL_SILENT:
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| 164 | break;
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| 165 | case AUDIT_FAIL_PRINTK:
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| 166 | printk(KERN_ERR "audit: %s\n", message);
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| 167 | break;
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| 168 | case AUDIT_FAIL_PANIC:
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| 169 | panic("audit: %s\n", message);
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| 170 | break;
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| 171 | }
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| 172 | }
|
| 173 |
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| 174 | static inline int audit_rate_check(void)
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| 175 | {
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| 176 | static unsigned long last_check = 0;
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| 177 | static int messages = 0;
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| 178 | static DEFINE_SPINLOCK(lock);
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| 179 | unsigned long flags;
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| 180 | unsigned long now;
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| 181 | unsigned long elapsed;
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| 182 | int retval = 0;
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| 183 |
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| 184 | if (!audit_rate_limit) return 1;
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| 185 |
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| 186 | spin_lock_irqsave(&lock, flags);
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| 187 | if (++messages < audit_rate_limit) {
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| 188 | retval = 1;
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| 189 | } else {
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| 190 | now = jiffies;
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| 191 | elapsed = now - last_check;
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| 192 | if (elapsed > HZ) {
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| 193 | last_check = now;
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| 194 | messages = 0;
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| 195 | retval = 1;
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| 196 | }
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| 197 | }
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| 198 | spin_unlock_irqrestore(&lock, flags);
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| 199 |
|
| 200 | return retval;
|
| 201 | }
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| 202 |
|
| 203 | |
| 204 | * audit_log_lost - conditionally log lost audit message event
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| 205 | * @message: the message stating reason for lost audit message
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| 206 | *
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| 207 | * Emit at least 1 message per second, even if audit_rate_check is
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| 208 | * throttling.
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| 209 | * Always increment the lost messages counter.
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| 210 |
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| 211 | void audit_log_lost(const char *message)
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| 212 | {
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| 213 | static unsigned long last_msg = 0;
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| 214 | static DEFINE_SPINLOCK(lock);
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| 215 | unsigned long flags;
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| 216 | unsigned long now;
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| 217 | int print;
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| 218 |
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| 219 | atomic_inc(&audit_lost);
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| 220 |
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| 221 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
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| 222 |
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| 223 | if (!print) {
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| 224 | spin_lock_irqsave(&lock, flags);
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| 225 | now = jiffies;
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| 226 | if (now - last_msg > HZ) {
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| 227 | print = 1;
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| 228 | last_msg = now;
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| 229 | }
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| 230 | spin_unlock_irqrestore(&lock, flags);
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| 231 | }
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| 232 |
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| 233 | if (print) {
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| 234 | printk(KERN_WARNING
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| 235 | "audit: audit_lost=%d audit_rate_limit=%d audit_backlog_limit=%d\n",
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| 236 | atomic_read(&audit_lost),
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| 237 | audit_rate_limit,
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| 238 | audit_backlog_limit);
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| 239 | audit_panic(message);
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| 240 | }
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| 241 | }
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| 242 |
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| 243 | static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sid)
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| 244 | {
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| 245 | int res, rc = 0, old = audit_rate_limit;
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| 246 |
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| 247 |
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| 248 | if (audit_enabled == 2)
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| 249 | res = 0;
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| 250 | else
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| 251 | res = 1;
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| 252 |
|
| 253 | if (sid) {
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| 254 | char *ctx = NULL;
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| 255 | u32 len;
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| 256 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) {
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| 257 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 258 | "audit_rate_limit=%d old=%d by auid=%u"
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| 259 | " subj=%s res=%d",
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| 260 | limit, old, loginuid, ctx, res);
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| 261 | kfree(ctx);
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| 262 | } else
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| 263 | res = 0;
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| 264 | }
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| 265 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 266 | "audit_rate_limit=%d old=%d by auid=%u res=%d",
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| 267 | limit, old, loginuid, res);
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| 268 |
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| 269 |
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| 270 | if (res == 1)
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| 271 | audit_rate_limit = limit;
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| 272 |
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| 273 | else if (rc == 0)
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| 274 | rc = -EPERM;
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| 275 | return rc;
|
| 276 | }
|
| 277 |
|
| 278 | static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sid)
|
| 279 | {
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| 280 | int res, rc = 0, old = audit_backlog_limit;
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| 281 |
|
| 282 |
|
| 283 | if (audit_enabled == 2)
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| 284 | res = 0;
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| 285 | else
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| 286 | res = 1;
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| 287 |
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| 288 | if (sid) {
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| 289 | char *ctx = NULL;
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| 290 | u32 len;
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| 291 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) {
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| 292 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 293 | "audit_backlog_limit=%d old=%d by auid=%u"
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| 294 | " subj=%s res=%d",
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| 295 | limit, old, loginuid, ctx, res);
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| 296 | kfree(ctx);
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| 297 | } else
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| 298 | res = 0;
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| 299 | }
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| 300 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 301 | "audit_backlog_limit=%d old=%d by auid=%u res=%d",
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| 302 | limit, old, loginuid, res);
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| 303 |
|
| 304 |
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| 305 | if (res == 1)
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| 306 | audit_backlog_limit = limit;
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| 307 |
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| 308 | else if (rc == 0)
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| 309 | rc = -EPERM;
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| 310 | return rc;
|
| 311 | }
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| 312 |
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| 313 | static int audit_set_enabled(int state, uid_t loginuid, u32 sid)
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| 314 | {
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| 315 | int res, rc = 0, old = audit_enabled;
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| 316 |
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| 317 | if (state < 0 || state > 2)
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| 318 | return -EINVAL;
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| 319 |
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| 320 |
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| 321 | if (audit_enabled == 2)
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| 322 | res = 0;
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| 323 | else
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| 324 | res = 1;
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| 325 |
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| 326 | if (sid) {
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| 327 | char *ctx = NULL;
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| 328 | u32 len;
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| 329 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) {
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| 330 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 331 | "audit_enabled=%d old=%d by auid=%u"
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| 332 | " subj=%s res=%d",
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| 333 | state, old, loginuid, ctx, res);
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| 334 | kfree(ctx);
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| 335 | } else
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| 336 | res = 0;
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| 337 | }
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| 338 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 339 | "audit_enabled=%d old=%d by auid=%u res=%d",
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| 340 | state, old, loginuid, res);
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| 341 |
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| 342 |
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| 343 | if (res == 1)
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| 344 | audit_enabled = state;
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| 345 |
|
| 346 | else if (rc == 0)
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| 347 | rc = -EPERM;
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| 348 | return rc;
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| 349 | }
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| 350 |
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| 351 | static int audit_set_failure(int state, uid_t loginuid, u32 sid)
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| 352 | {
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| 353 | int res, rc = 0, old = audit_failure;
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| 354 |
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| 355 | if (state != AUDIT_FAIL_SILENT
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| 356 | && state != AUDIT_FAIL_PRINTK
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| 357 | && state != AUDIT_FAIL_PANIC)
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| 358 | return -EINVAL;
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| 359 |
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| 360 |
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| 361 | if (audit_enabled == 2)
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| 362 | res = 0;
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| 363 | else
|
| 364 | res = 1;
|
| 365 |
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| 366 | if (sid) {
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| 367 | char *ctx = NULL;
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| 368 | u32 len;
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| 369 | if ((rc = selinux_sid_to_string(sid, &ctx, &len)) == 0) {
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| 370 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 371 | "audit_failure=%d old=%d by auid=%u"
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| 372 | " subj=%s res=%d",
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| 373 | state, old, loginuid, ctx, res);
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| 374 | kfree(ctx);
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| 375 | } else
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| 376 | res = 0;
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| 377 | }
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| 378 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
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| 379 | "audit_failure=%d old=%d by auid=%u res=%d",
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| 380 | state, old, loginuid, res);
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| 381 |
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| 382 |
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| 383 | if (res == 1)
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| 384 | audit_failure = state;
|
| 385 |
|
| 386 | else if (rc == 0)
|
| 387 | rc = -EPERM;
|
| 388 | return rc;
|
| 389 | }
|
| 390 |
|
| 391 | static int kauditd_thread(void *dummy)
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| 392 | {
|
| 393 | struct sk_buff *skb;
|
| 394 |
|
| 395 | set_freezable();
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| 396 | while (!kthread_should_stop()) {
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| 397 | skb = skb_dequeue(&audit_skb_queue);
|
| 398 | wake_up(&audit_backlog_wait);
|
| 399 | if (skb) {
|
| 400 | if (audit_pid) {
|
| 401 | int err = netlink_unicast(audit_sock, skb, audit_pid, 0);
|
| 402 | if (err < 0) {
|
| 403 | BUG_ON(err != -ECONNREFUSED);
|
| 404 | printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
|
| 405 | audit_pid = 0;
|
| 406 | }
|
| 407 | } else {
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| 408 | printk(KERN_NOTICE "%s\n", skb->data + NLMSG_SPACE(0));
|
| 409 | kfree_skb(skb);
|
| 410 | }
|
| 411 | } else {
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| 412 | DECLARE_WAITQUEUE(wait, current);
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| 413 | set_current_state(TASK_INTERRUPTIBLE);
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| 414 | add_wait_queue(&kauditd_wait, &wait);
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| 415 |
|
| 416 | if (!skb_queue_len(&audit_skb_queue)) {
|
| 417 | try_to_freeze();
|
| 418 | schedule();
|
| 419 | }
|
| 420 |
|
| 421 | __set_current_state(TASK_RUNNING);
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| 422 | remove_wait_queue(&kauditd_wait, &wait);
|
| 423 | }
|
| 424 | }
|
| 425 | return 0;
|
| 426 | }
|
| 427 |
|
| 428 | static int audit_prepare_user_tty(pid_t pid, uid_t loginuid)
|
| 429 | {
|
| 430 | struct task_struct *tsk;
|
| 431 | int err;
|
| 432 |
|
| 433 | read_lock(&tasklist_lock);
|
| 434 | tsk = find_task_by_pid(pid);
|
| 435 | err = -ESRCH;
|
| 436 | if (!tsk)
|
| 437 | goto out;
|
| 438 | err = 0;
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| 439 |
|
| 440 | spin_lock_irq(&tsk->sighand->siglock);
|
| 441 | if (!tsk->signal->audit_tty)
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| 442 | err = -EPERM;
|
| 443 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 444 | if (err)
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| 445 | goto out;
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| 446 |
|
| 447 | tty_audit_push_task(tsk, loginuid);
|
| 448 | out:
|
| 449 | read_unlock(&tasklist_lock);
|
| 450 | return err;
|
| 451 | }
|
| 452 |
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| 453 | int audit_send_list(void *_dest)
|
| 454 | {
|
| 455 | struct audit_netlink_list *dest = _dest;
|
| 456 | int pid = dest->pid;
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| 457 | struct sk_buff *skb;
|
| 458 |
|
| 459 |
|
| 460 | mutex_lock(&audit_cmd_mutex);
|
| 461 | mutex_unlock(&audit_cmd_mutex);
|
| 462 |
|
| 463 | while ((skb = __skb_dequeue(&dest->q)) != NULL)
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| 464 | netlink_unicast(audit_sock, skb, pid, 0);
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| 465 |
|
| 466 | kfree(dest);
|
| 467 |
|
| 468 | return 0;
|
| 469 | }
|
| 470 |
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| 471 | struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
|
| 472 | int multi, void *payload, int size)
|
| 473 | {
|
| 474 | struct sk_buff *skb;
|
| 475 | struct nlmsghdr *nlh;
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| 476 | int len = NLMSG_SPACE(size);
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| 477 | void *data;
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| 478 | int flags = multi ? NLM_F_MULTI : 0;
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| 479 | int t = done ? NLMSG_DONE : type;
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| 480 |
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| 481 | skb = alloc_skb(len, GFP_KERNEL);
|
| 482 | if (!skb)
|
| 483 | return NULL;
|
| 484 |
|
| 485 | nlh = NLMSG_PUT(skb, pid, seq, t, size);
|
| 486 | nlh->nlmsg_flags = flags;
|
| 487 | data = NLMSG_DATA(nlh);
|
| 488 | memcpy(data, payload, size);
|
| 489 | return skb;
|
| 490 |
|
| 491 | nlmsg_failure:
|
| 492 | if (skb)
|
| 493 | kfree_skb(skb);
|
| 494 | return NULL;
|
| 495 | }
|
| 496 |
|
| 497 | |
| 498 | * audit_send_reply - send an audit reply message via netlink
|
| 499 | * @pid: process id to send reply to
|
| 500 | * @seq: sequence number
|
| 501 | * @type: audit message type
|
| 502 | * @done: done (last) flag
|
| 503 | * @multi: multi-part message flag
|
| 504 | * @payload: payload data
|
| 505 | * @size: payload size
|
| 506 | *
|
| 507 | * Allocates an skb, builds the netlink message, and sends it to the pid.
|
| 508 | * No failure notifications.
|
| 509 |
|
| 510 | void audit_send_reply(int pid, int seq, int type, int done, int multi,
|
| 511 | void *payload, int size)
|
| 512 | {
|
| 513 | struct sk_buff *skb;
|
| 514 | skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
|
| 515 | if (!skb)
|
| 516 | return;
|
| 517 | |
| 518 | because our timeout is set to infinite.
|
| 519 | netlink_unicast(audit_sock, skb, pid, 0);
|
| 520 | return;
|
| 521 | }
|
| 522 |
|
| 523 | |
| 524 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
|
| 525 | * control messages.
|
| 526 |
|
| 527 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
|
| 528 | {
|
| 529 | int err = 0;
|
| 530 |
|
| 531 | switch (msg_type) {
|
| 532 | case AUDIT_GET:
|
| 533 | case AUDIT_LIST:
|
| 534 | case AUDIT_LIST_RULES:
|
| 535 | case AUDIT_SET:
|
| 536 | case AUDIT_ADD:
|
| 537 | case AUDIT_ADD_RULE:
|
| 538 | case AUDIT_DEL:
|
| 539 | case AUDIT_DEL_RULE:
|
| 540 | case AUDIT_SIGNAL_INFO:
|
| 541 | case AUDIT_TTY_GET:
|
| 542 | case AUDIT_TTY_SET:
|
| 543 | if (security_netlink_recv(skb, CAP_AUDIT_CONTROL))
|
| 544 | err = -EPERM;
|
| 545 | break;
|
| 546 | case AUDIT_USER:
|
| 547 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 548 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 549 | if (security_netlink_recv(skb, CAP_AUDIT_WRITE))
|
| 550 | err = -EPERM;
|
| 551 | break;
|
| 552 | default:
|
| 553 | err = -EINVAL;
|
| 554 | }
|
| 555 |
|
| 556 | return err;
|
| 557 | }
|
| 558 |
|
| 559 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
| 560 | {
|
| 561 | u32 uid, pid, seq, sid;
|
| 562 | void *data;
|
| 563 | struct audit_status *status_get, status_set;
|
| 564 | int err;
|
| 565 | struct audit_buffer *ab;
|
| 566 | u16 msg_type = nlh->nlmsg_type;
|
| 567 | uid_t loginuid;
|
| 568 | struct audit_sig_info *sig_data;
|
| 569 | char *ctx;
|
| 570 | u32 len;
|
| 571 |
|
| 572 | err = audit_netlink_ok(skb, msg_type);
|
| 573 | if (err)
|
| 574 | return err;
|
| 575 |
|
| 576 | |
| 577 | * start kauditd to talk to it
|
| 578 | if (!kauditd_task)
|
| 579 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
|
| 580 | if (IS_ERR(kauditd_task)) {
|
| 581 | err = PTR_ERR(kauditd_task);
|
| 582 | kauditd_task = NULL;
|
| 583 | return err;
|
| 584 | }
|
| 585 |
|
| 586 | pid = NETLINK_CREDS(skb)->pid;
|
| 587 | uid = NETLINK_CREDS(skb)->uid;
|
| 588 | loginuid = NETLINK_CB(skb).loginuid;
|
| 589 | sid = NETLINK_CB(skb).sid;
|
| 590 | seq = nlh->nlmsg_seq;
|
| 591 | data = NLMSG_DATA(nlh);
|
| 592 |
|
| 593 | switch (msg_type) {
|
| 594 | case AUDIT_GET:
|
| 595 | status_set.enabled = audit_enabled;
|
| 596 | status_set.failure = audit_failure;
|
| 597 | status_set.pid = audit_pid;
|
| 598 | status_set.rate_limit = audit_rate_limit;
|
| 599 | status_set.backlog_limit = audit_backlog_limit;
|
| 600 | status_set.lost = atomic_read(&audit_lost);
|
| 601 | status_set.backlog = skb_queue_len(&audit_skb_queue);
|
| 602 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
|
| 603 | &status_set, sizeof(status_set));
|
| 604 | break;
|
| 605 | case AUDIT_SET:
|
| 606 | if (nlh->nlmsg_len < sizeof(struct audit_status))
|
| 607 | return -EINVAL;
|
| 608 | status_get = (struct audit_status *)data;
|
| 609 | if (status_get->mask & AUDIT_STATUS_ENABLED) {
|
| 610 | err = audit_set_enabled(status_get->enabled,
|
| 611 | loginuid, sid);
|
| 612 | if (err < 0) return err;
|
| 613 | }
|
| 614 | if (status_get->mask & AUDIT_STATUS_FAILURE) {
|
| 615 | err = audit_set_failure(status_get->failure,
|
| 616 | loginuid, sid);
|
| 617 | if (err < 0) return err;
|
| 618 | }
|
| 619 | if (status_get->mask & AUDIT_STATUS_PID) {
|
| 620 | int old = audit_pid;
|
| 621 | if (sid) {
|
| 622 | if ((err = selinux_sid_to_string(
|
| 623 | sid, &ctx, &len)))
|
| 624 | return err;
|
| 625 | else
|
| 626 | audit_log(NULL, GFP_KERNEL,
|
| 627 | AUDIT_CONFIG_CHANGE,
|
| 628 | "audit_pid=%d old=%d by auid=%u subj=%s",
|
| 629 | status_get->pid, old,
|
| 630 | loginuid, ctx);
|
| 631 | kfree(ctx);
|
| 632 | } else
|
| 633 | audit_log(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE,
|
| 634 | "audit_pid=%d old=%d by auid=%u",
|
| 635 | status_get->pid, old, loginuid);
|
| 636 | audit_pid = status_get->pid;
|
| 637 | }
|
| 638 | if (status_get->mask & AUDIT_STATUS_RATE_LIMIT)
|
| 639 | err = audit_set_rate_limit(status_get->rate_limit,
|
| 640 | loginuid, sid);
|
| 641 | if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
|
| 642 | err = audit_set_backlog_limit(status_get->backlog_limit,
|
| 643 | loginuid, sid);
|
| 644 | break;
|
| 645 | case AUDIT_USER:
|
| 646 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 647 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 648 | if (!audit_enabled && msg_type != AUDIT_USER_AVC)
|
| 649 | return 0;
|
| 650 |
|
| 651 | err = audit_filter_user(&NETLINK_CB(skb), msg_type);
|
| 652 | if (err == 1) {
|
| 653 | err = 0;
|
| 654 | if (msg_type == AUDIT_USER_TTY) {
|
| 655 | err = audit_prepare_user_tty(pid, loginuid);
|
| 656 | if (err)
|
| 657 | break;
|
| 658 | }
|
| 659 | ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
|
| 660 | if (ab) {
|
| 661 | audit_log_format(ab,
|
| 662 | "user pid=%d uid=%u auid=%u",
|
| 663 | pid, uid, loginuid);
|
| 664 | if (sid) {
|
| 665 | if (selinux_sid_to_string(
|
| 666 | sid, &ctx, &len)) {
|
| 667 | audit_log_format(ab,
|
| 668 | " ssid=%u", sid);
|
| 669 |
|
| 670 | } else
|
| 671 | audit_log_format(ab,
|
| 672 | " subj=%s", ctx);
|
| 673 | kfree(ctx);
|
| 674 | }
|
| 675 | if (msg_type != AUDIT_USER_TTY)
|
| 676 | audit_log_format(ab, " msg='%.1024s'",
|
| 677 | (char *)data);
|
| 678 | else {
|
| 679 | int size;
|
| 680 |
|
| 681 | audit_log_format(ab, " msg=");
|
| 682 | size = nlmsg_len(nlh);
|
| 683 | audit_log_n_untrustedstring(ab, size,
|
| 684 | data);
|
| 685 | }
|
| 686 | audit_set_pid(ab, pid);
|
| 687 | audit_log_end(ab);
|
| 688 | }
|
| 689 | }
|
| 690 | break;
|
| 691 | case AUDIT_ADD:
|
| 692 | case AUDIT_DEL:
|
| 693 | if (nlmsg_len(nlh) < sizeof(struct audit_rule))
|
| 694 | return -EINVAL;
|
| 695 | if (audit_enabled == 2) {
|
| 696 | ab = audit_log_start(NULL, GFP_KERNEL,
|
| 697 | AUDIT_CONFIG_CHANGE);
|
| 698 | if (ab) {
|
| 699 | audit_log_format(ab,
|
| 700 | "pid=%d uid=%u auid=%u",
|
| 701 | pid, uid, loginuid);
|
| 702 | if (sid) {
|
| 703 | if (selinux_sid_to_string(
|
| 704 | sid, &ctx, &len)) {
|
| 705 | audit_log_format(ab,
|
| 706 | " ssid=%u", sid);
|
| 707 |
|
| 708 | } else
|
| 709 | audit_log_format(ab,
|
| 710 | " subj=%s", ctx);
|
| 711 | kfree(ctx);
|
| 712 | }
|
| 713 | audit_log_format(ab, " audit_enabled=%d res=0",
|
| 714 | audit_enabled);
|
| 715 | audit_log_end(ab);
|
| 716 | }
|
| 717 | return -EPERM;
|
| 718 | }
|
| 719 |
|
| 720 | case AUDIT_LIST:
|
| 721 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
|
| 722 | uid, seq, data, nlmsg_len(nlh),
|
| 723 | loginuid, sid);
|
| 724 | break;
|
| 725 | case AUDIT_ADD_RULE:
|
| 726 | case AUDIT_DEL_RULE:
|
| 727 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
|
| 728 | return -EINVAL;
|
| 729 | if (audit_enabled == 2) {
|
| 730 | ab = audit_log_start(NULL, GFP_KERNEL,
|
| 731 | AUDIT_CONFIG_CHANGE);
|
| 732 | if (ab) {
|
| 733 | audit_log_format(ab,
|
| 734 | "pid=%d uid=%u auid=%u",
|
| 735 | pid, uid, loginuid);
|
| 736 | if (sid) {
|
| 737 | if (selinux_sid_to_string(
|
| 738 | sid, &ctx, &len)) {
|
| 739 | audit_log_format(ab,
|
| 740 | " ssid=%u", sid);
|
| 741 |
|
| 742 | } else
|
| 743 | audit_log_format(ab,
|
| 744 | " subj=%s", ctx);
|
| 745 | kfree(ctx);
|
| 746 | }
|
| 747 | audit_log_format(ab, " audit_enabled=%d res=0",
|
| 748 | audit_enabled);
|
| 749 | audit_log_end(ab);
|
| 750 | }
|
| 751 | return -EPERM;
|
| 752 | }
|
| 753 |
|
| 754 | case AUDIT_LIST_RULES:
|
| 755 | err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid,
|
| 756 | uid, seq, data, nlmsg_len(nlh),
|
| 757 | loginuid, sid);
|
| 758 | break;
|
| 759 | case AUDIT_SIGNAL_INFO:
|
| 760 | err = selinux_sid_to_string(audit_sig_sid, &ctx, &len);
|
| 761 | if (err)
|
| 762 | return err;
|
| 763 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
|
| 764 | if (!sig_data) {
|
| 765 | kfree(ctx);
|
| 766 | return -ENOMEM;
|
| 767 | }
|
| 768 | sig_data->uid = audit_sig_uid;
|
| 769 | sig_data->pid = audit_sig_pid;
|
| 770 | memcpy(sig_data->ctx, ctx, len);
|
| 771 | kfree(ctx);
|
| 772 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
|
| 773 | 0, 0, sig_data, sizeof(*sig_data) + len);
|
| 774 | kfree(sig_data);
|
| 775 | break;
|
| 776 | case AUDIT_TTY_GET: {
|
| 777 | struct audit_tty_status s;
|
| 778 | struct task_struct *tsk;
|
| 779 |
|
| 780 | read_lock(&tasklist_lock);
|
| 781 | tsk = find_task_by_pid(pid);
|
| 782 | if (!tsk)
|
| 783 | err = -ESRCH;
|
| 784 | else {
|
| 785 | spin_lock_irq(&tsk->sighand->siglock);
|
| 786 | s.enabled = tsk->signal->audit_tty != 0;
|
| 787 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 788 | }
|
| 789 | read_unlock(&tasklist_lock);
|
| 790 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_TTY_GET, 0, 0,
|
| 791 | &s, sizeof(s));
|
| 792 | break;
|
| 793 | }
|
| 794 | case AUDIT_TTY_SET: {
|
| 795 | struct audit_tty_status *s;
|
| 796 | struct task_struct *tsk;
|
| 797 |
|
| 798 | if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
|
| 799 | return -EINVAL;
|
| 800 | s = data;
|
| 801 | if (s->enabled != 0 && s->enabled != 1)
|
| 802 | return -EINVAL;
|
| 803 | read_lock(&tasklist_lock);
|
| 804 | tsk = find_task_by_pid(pid);
|
| 805 | if (!tsk)
|
| 806 | err = -ESRCH;
|
| 807 | else {
|
| 808 | spin_lock_irq(&tsk->sighand->siglock);
|
| 809 | tsk->signal->audit_tty = s->enabled != 0;
|
| 810 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 811 | }
|
| 812 | read_unlock(&tasklist_lock);
|
| 813 | break;
|
| 814 | }
|
| 815 | default:
|
| 816 | err = -EINVAL;
|
| 817 | break;
|
| 818 | }
|
| 819 |
|
| 820 | return err < 0 ? err : 0;
|
| 821 | }
|
| 822 |
|
| 823 | |
| 824 | * Get message from skb (based on rtnetlink_rcv_skb). Each message is
|
| 825 | * processed by audit_receive_msg. Malformed skbs with wrong length are
|
| 826 | * discarded silently.
|
| 827 |
|
| 828 | static void audit_receive_skb(struct sk_buff *skb)
|
| 829 | {
|
| 830 | int err;
|
| 831 | struct nlmsghdr *nlh;
|
| 832 | u32 rlen;
|
| 833 |
|
| 834 | while (skb->len >= NLMSG_SPACE(0)) {
|
| 835 | nlh = nlmsg_hdr(skb);
|
| 836 | if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
|
| 837 | return;
|
| 838 | rlen = NLMSG_ALIGN(nlh->nlmsg_len);
|
| 839 | if (rlen > skb->len)
|
| 840 | rlen = skb->len;
|
| 841 | if ((err = audit_receive_msg(skb, nlh))) {
|
| 842 | netlink_ack(skb, nlh, err);
|
| 843 | } else if (nlh->nlmsg_flags & NLM_F_ACK)
|
| 844 | netlink_ack(skb, nlh, 0);
|
| 845 | skb_pull(skb, rlen);
|
| 846 | }
|
| 847 | }
|
| 848 |
|
| 849 |
|
| 850 | static void audit_receive(struct sock *sk, int length)
|
| 851 | {
|
| 852 | struct sk_buff *skb;
|
| 853 | unsigned int qlen;
|
| 854 |
|
| 855 | mutex_lock(&audit_cmd_mutex);
|
| 856 |
|
| 857 | for (qlen = skb_queue_len(&sk->sk_receive_queue); qlen; qlen--) {
|
| 858 | skb = skb_dequeue(&sk->sk_receive_queue);
|
| 859 | audit_receive_skb(skb);
|
| 860 | kfree_skb(skb);
|
| 861 | }
|
| 862 | mutex_unlock(&audit_cmd_mutex);
|
| 863 | }
|
| 864 |
|
| 865 | #ifdef CONFIG_AUDITSYSCALL
|
| 866 | static const struct inotify_operations audit_inotify_ops = {
|
| 867 | .handle_event = audit_handle_ievent,
|
| 868 | .destroy_watch = audit_free_parent,
|
| 869 | };
|
| 870 | #endif
|
| 871 |
|
| 872 |
|
| 873 | static int __init audit_init(void)
|
| 874 | {
|
| 875 | int i;
|
| 876 |
|
| 877 | printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
|
| 878 | audit_default ? "enabled" : "disabled");
|
| 879 | audit_sock = netlink_kernel_create(NETLINK_AUDIT, 0, audit_receive,
|
| 880 | NULL, THIS_MODULE);
|
| 881 | if (!audit_sock)
|
| 882 | audit_panic("cannot initialize netlink socket");
|
| 883 | else
|
| 884 | audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
|
| 885 |
|
| 886 | skb_queue_head_init(&audit_skb_queue);
|
| 887 | audit_initialized = 1;
|
| 888 | audit_enabled = audit_default;
|
| 889 |
|
| 890 | |
| 891 | * when a new policy is loaded.
|
| 892 | selinux_audit_set_callback(&selinux_audit_rule_update);
|
| 893 |
|
| 894 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
|
| 895 |
|
| 896 | #ifdef CONFIG_AUDITSYSCALL
|
| 897 | audit_ih = inotify_init(&audit_inotify_ops);
|
| 898 | if (IS_ERR(audit_ih))
|
| 899 | audit_panic("cannot initialize inotify handle");
|
| 900 | #endif
|
| 901 |
|
| 902 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
|
| 903 | INIT_LIST_HEAD(&audit_inode_hash[i]);
|
| 904 |
|
| 905 | return 0;
|
| 906 | }
|
| 907 | __initcall(audit_init);
|
| 908 |
|
| 909 |
|
| 910 | static int __init audit_enable(char *str)
|
| 911 | {
|
| 912 | audit_default = !!simple_strtol(str, NULL, 0);
|
| 913 | printk(KERN_INFO "audit: %s%s\n",
|
| 914 | audit_default ? "enabled" : "disabled",
|
| 915 | audit_initialized ? "" : " (after initialization)");
|
| 916 | if (audit_initialized)
|
| 917 | audit_enabled = audit_default;
|
| 918 | return 1;
|
| 919 | }
|
| 920 |
|
| 921 | __setup("audit=", audit_enable);
|
| 922 |
|
| 923 | static void audit_buffer_free(struct audit_buffer *ab)
|
| 924 | {
|
| 925 | unsigned long flags;
|
| 926 |
|
| 927 | if (!ab)
|
| 928 | return;
|
| 929 |
|
| 930 | if (ab->skb)
|
| 931 | kfree_skb(ab->skb);
|
| 932 |
|
| 933 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 934 | if (audit_freelist_count > AUDIT_MAXFREE)
|
| 935 | kfree(ab);
|
| 936 | else {
|
| 937 | audit_freelist_count++;
|
| 938 | list_add(&ab->list, &audit_freelist);
|
| 939 | }
|
| 940 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 941 | }
|
| 942 |
|
| 943 | static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
|
| 944 | gfp_t gfp_mask, int type)
|
| 945 | {
|
| 946 | unsigned long flags;
|
| 947 | struct audit_buffer *ab = NULL;
|
| 948 | struct nlmsghdr *nlh;
|
| 949 |
|
| 950 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 951 | if (!list_empty(&audit_freelist)) {
|
| 952 | ab = list_entry(audit_freelist.next,
|
| 953 | struct audit_buffer, list);
|
| 954 | list_del(&ab->list);
|
| 955 | --audit_freelist_count;
|
| 956 | }
|
| 957 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 958 |
|
| 959 | if (!ab) {
|
| 960 | ab = kmalloc(sizeof(*ab), gfp_mask);
|
| 961 | if (!ab)
|
| 962 | goto err;
|
| 963 | }
|
| 964 |
|
| 965 | ab->skb = alloc_skb(AUDIT_BUFSIZ, gfp_mask);
|
| 966 | if (!ab->skb)
|
| 967 | goto err;
|
| 968 |
|
| 969 | ab->ctx = ctx;
|
| 970 | ab->gfp_mask = gfp_mask;
|
| 971 | nlh = (struct nlmsghdr *)skb_put(ab->skb, NLMSG_SPACE(0));
|
| 972 | nlh->nlmsg_type = type;
|
| 973 | nlh->nlmsg_flags = 0;
|
| 974 | nlh->nlmsg_pid = 0;
|
| 975 | nlh->nlmsg_seq = 0;
|
| 976 | return ab;
|
| 977 | err:
|
| 978 | audit_buffer_free(ab);
|
| 979 | return NULL;
|
| 980 | }
|
| 981 |
|
| 982 | |
| 983 | * audit_serial - compute a serial number for the audit record
|
| 984 | *
|
| 985 | * Compute a serial number for the audit record. Audit records are
|
| 986 | * written to user-space as soon as they are generated, so a complete
|
| 987 | * audit record may be written in several pieces. The timestamp of the
|
| 988 | * record and this serial number are used by the user-space tools to
|
| 989 | * determine which pieces belong to the same audit record. The
|
| 990 | * (timestamp,serial) tuple is unique for each syscall and is live from
|
| 991 | * syscall entry to syscall exit.
|
| 992 | *
|
| 993 | * NOTE: Another possibility is to store the formatted records off the
|
| 994 | * audit context (for those records that have a context), and emit them
|
| 995 | * all at syscall exit. However, this could delay the reporting of
|
| 996 | * significant errors until syscall exit (or never, if the system
|
| 997 | * halts).
|
| 998 |
|
| 999 | unsigned int audit_serial(void)
|
| 1000 | {
|
| 1001 | static DEFINE_SPINLOCK(serial_lock);
|
| 1002 | static unsigned int serial = 0;
|
| 1003 |
|
| 1004 | unsigned long flags;
|
| 1005 | unsigned int ret;
|
| 1006 |
|
| 1007 | spin_lock_irqsave(&serial_lock, flags);
|
| 1008 | do {
|
| 1009 | ret = ++serial;
|
| 1010 | } while (unlikely(!ret));
|
| 1011 | spin_unlock_irqrestore(&serial_lock, flags);
|
| 1012 |
|
| 1013 | return ret;
|
| 1014 | }
|
| 1015 |
|
| 1016 | static inline void audit_get_stamp(struct audit_context *ctx,
|
| 1017 | struct timespec *t, unsigned int *serial)
|
| 1018 | {
|
| 1019 | if (ctx)
|
| 1020 | auditsc_get_stamp(ctx, t, serial);
|
| 1021 | else {
|
| 1022 | *t = CURRENT_TIME;
|
| 1023 | *serial = audit_serial();
|
| 1024 | }
|
| 1025 | }
|
| 1026 |
|
| 1027 | |
| 1028 | * audit buffer, but then no locking is required for calls to
|
| 1029 | * audit_log_*format. If the tsk is a task that is currently in a
|
| 1030 | * syscall, then the syscall is marked as auditable and an audit record
|
| 1031 | * will be written at syscall exit. If there is no associated task, tsk
|
| 1032 | * should be NULL.
|
| 1033 |
|
| 1034 | |
| 1035 | * audit_log_start - obtain an audit buffer
|
| 1036 | * @ctx: audit_context (may be NULL)
|
| 1037 | * @gfp_mask: type of allocation
|
| 1038 | * @type: audit message type
|
| 1039 | *
|
| 1040 | * Returns audit_buffer pointer on success or NULL on error.
|
| 1041 | *
|
| 1042 | * Obtain an audit buffer. This routine does locking to obtain the
|
| 1043 | * audit buffer, but then no locking is required for calls to
|
| 1044 | * audit_log_*format. If the task (ctx) is a task that is currently in a
|
| 1045 | * syscall, then the syscall is marked as auditable and an audit record
|
| 1046 | * will be written at syscall exit. If there is no associated task, then
|
| 1047 | * task context (ctx) should be NULL.
|
| 1048 |
|
| 1049 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
|
| 1050 | int type)
|
| 1051 | {
|
| 1052 | struct audit_buffer *ab = NULL;
|
| 1053 | struct timespec t;
|
| 1054 | unsigned int serial;
|
| 1055 | int reserve;
|
| 1056 | unsigned long timeout_start = jiffies;
|
| 1057 |
|
| 1058 | if (!audit_initialized)
|
| 1059 | return NULL;
|
| 1060 |
|
| 1061 | if (unlikely(audit_filter_type(type)))
|
| 1062 | return NULL;
|
| 1063 |
|
| 1064 | if (gfp_mask & __GFP_WAIT)
|
| 1065 | reserve = 0;
|
| 1066 | else
|
| 1067 | reserve = 5; |
| 1068 | entries over the normal backlog limit
|
| 1069 |
|
| 1070 | while (audit_backlog_limit
|
| 1071 | && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
|
| 1072 | if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
|
| 1073 | && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
|
| 1074 |
|
| 1075 |
|
| 1076 | DECLARE_WAITQUEUE(wait, current);
|
| 1077 | set_current_state(TASK_INTERRUPTIBLE);
|
| 1078 | add_wait_queue(&audit_backlog_wait, &wait);
|
| 1079 |
|
| 1080 | if (audit_backlog_limit &&
|
| 1081 | skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
|
| 1082 | schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
|
| 1083 |
|
| 1084 | __set_current_state(TASK_RUNNING);
|
| 1085 | remove_wait_queue(&audit_backlog_wait, &wait);
|
| 1086 | continue;
|
| 1087 | }
|
| 1088 | if (audit_rate_check())
|
| 1089 | printk(KERN_WARNING
|
| 1090 | "audit: audit_backlog=%d > "
|
| 1091 | "audit_backlog_limit=%d\n",
|
| 1092 | skb_queue_len(&audit_skb_queue),
|
| 1093 | audit_backlog_limit);
|
| 1094 | audit_log_lost("backlog limit exceeded");
|
| 1095 | audit_backlog_wait_time = audit_backlog_wait_overflow;
|
| 1096 | wake_up(&audit_backlog_wait);
|
| 1097 | return NULL;
|
| 1098 | }
|
| 1099 |
|
| 1100 | ab = audit_buffer_alloc(ctx, gfp_mask, type);
|
| 1101 | if (!ab) {
|
| 1102 | audit_log_lost("out of memory in audit_log_start");
|
| 1103 | return NULL;
|
| 1104 | }
|
| 1105 |
|
| 1106 | audit_get_stamp(ab->ctx, &t, &serial);
|
| 1107 |
|
| 1108 | audit_log_format(ab, "audit(%lu.%03lu:%u): ",
|
| 1109 | t.tv_sec, t.tv_nsec/1000000, serial);
|
| 1110 | return ab;
|
| 1111 | }
|
| 1112 |
|
| 1113 | |
| 1114 | * audit_expand - expand skb in the audit buffer
|
| 1115 | * @ab: audit_buffer
|
| 1116 | * @extra: space to add at tail of the skb
|
| 1117 | *
|
| 1118 | * Returns 0 (no space) on failed expansion, or available space if
|
| 1119 | * successful.
|
| 1120 |
|
| 1121 | static inline int audit_expand(struct audit_buffer *ab, int extra)
|
| 1122 | {
|
| 1123 | struct sk_buff *skb = ab->skb;
|
| 1124 | int ret = pskb_expand_head(skb, skb_headroom(skb), extra,
|
| 1125 | ab->gfp_mask);
|
| 1126 | if (ret < 0) {
|
| 1127 | audit_log_lost("out of memory in audit_expand");
|
| 1128 | return 0;
|
| 1129 | }
|
| 1130 | return skb_tailroom(skb);
|
| 1131 | }
|
| 1132 |
|
| 1133 | |
| 1134 | * Format an audit message into the audit buffer. If there isn't enough
|
| 1135 | * room in the audit buffer, more room will be allocated and vsnprint
|
| 1136 | * will be called a second time. Currently, we assume that a printk
|
| 1137 | * can't format message larger than 1024 bytes, so we don't either.
|
| 1138 |
|
| 1139 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
|
| 1140 | va_list args)
|
| 1141 | {
|
| 1142 | int len, avail;
|
| 1143 | struct sk_buff *skb;
|
| 1144 | va_list args2;
|
| 1145 |
|
| 1146 | if (!ab)
|
| 1147 | return;
|
| 1148 |
|
| 1149 | BUG_ON(!ab->skb);
|
| 1150 | skb = ab->skb;
|
| 1151 | avail = skb_tailroom(skb);
|
| 1152 | if (avail == 0) {
|
| 1153 | avail = audit_expand(ab, AUDIT_BUFSIZ);
|
| 1154 | if (!avail)
|
| 1155 | goto out;
|
| 1156 | }
|
| 1157 | va_copy(args2, args);
|
| 1158 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
|
| 1159 | if (len >= avail) {
|
| 1160 | |
| 1161 | * here and AUDIT_BUFSIZ is at least 1024, then we can
|
| 1162 | * log everything that printk could have logged.
|
| 1163 | avail = audit_expand(ab,
|
| 1164 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
|
| 1165 | if (!avail)
|
| 1166 | goto out;
|
| 1167 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
|
| 1168 | }
|
| 1169 | if (len > 0)
|
| 1170 | skb_put(skb, len);
|
| 1171 | out:
|
| 1172 | return;
|
| 1173 | }
|
| 1174 |
|
| 1175 | |
| 1176 | * audit_log_format - format a message into the audit buffer.
|
| 1177 | * @ab: audit_buffer
|
| 1178 | * @fmt: format string
|
| 1179 | * @...: optional parameters matching @fmt string
|
| 1180 | *
|
| 1181 | * All the work is done in audit_log_vformat.
|
| 1182 |
|
| 1183 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
|
| 1184 | {
|
| 1185 | va_list args;
|
| 1186 |
|
| 1187 | if (!ab)
|
| 1188 | return;
|
| 1189 | va_start(args, fmt);
|
| 1190 | audit_log_vformat(ab, fmt, args);
|
| 1191 | va_end(args);
|
| 1192 | }
|
| 1193 |
|
| 1194 | |
| 1195 | * audit_log_hex - convert a buffer to hex and append it to the audit skb
|
| 1196 | * @ab: the audit_buffer
|
| 1197 | * @buf: buffer to convert to hex
|
| 1198 | * @len: length of @buf to be converted
|
| 1199 | *
|
| 1200 | * No return value; failure to expand is silently ignored.
|
| 1201 | *
|
| 1202 | * This function will take the passed buf and convert it into a string of
|
| 1203 | * ascii hex digits. The new string is placed onto the skb.
|
| 1204 |
|
| 1205 | void audit_log_hex(struct audit_buffer *ab, const unsigned char *buf,
|
| 1206 | size_t len)
|
| 1207 | {
|
| 1208 | int i, avail, new_len;
|
| 1209 | unsigned char *ptr;
|
| 1210 | struct sk_buff *skb;
|
| 1211 | static const unsigned char *hex = "0123456789ABCDEF";
|
| 1212 |
|
| 1213 | if (!ab)
|
| 1214 | return;
|
| 1215 |
|
| 1216 | BUG_ON(!ab->skb);
|
| 1217 | skb = ab->skb;
|
| 1218 | avail = skb_tailroom(skb);
|
| 1219 | new_len = len<<1;
|
| 1220 | if (new_len >= avail) {
|
| 1221 |
|
| 1222 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
|
| 1223 | avail = audit_expand(ab, new_len);
|
| 1224 | if (!avail)
|
| 1225 | return;
|
| 1226 | }
|
| 1227 |
|
| 1228 | ptr = skb_tail_pointer(skb);
|
| 1229 | for (i=0; i<len; i++) {
|
| 1230 | *ptr++ = hex[(buf[i] & 0xF0)>>4];
|
| 1231 | *ptr++ = hex[buf[i] & 0x0F];
|
| 1232 | }
|
| 1233 | *ptr = 0;
|
| 1234 | skb_put(skb, len << 1);
|
| 1235 | }
|
| 1236 |
|
| 1237 | |
| 1238 | * Format a string of no more than slen characters into the audit buffer,
|
| 1239 | * enclosed in quote marks.
|
| 1240 |
|
| 1241 | static void audit_log_n_string(struct audit_buffer *ab, size_t slen,
|
| 1242 | const char *string)
|
| 1243 | {
|
| 1244 | int avail, new_len;
|
| 1245 | unsigned char *ptr;
|
| 1246 | struct sk_buff *skb;
|
| 1247 |
|
| 1248 | if (!ab)
|
| 1249 | return;
|
| 1250 |
|
| 1251 | BUG_ON(!ab->skb);
|
| 1252 | skb = ab->skb;
|
| 1253 | avail = skb_tailroom(skb);
|
| 1254 | new_len = slen + 3;
|
| 1255 | if (new_len > avail) {
|
| 1256 | avail = audit_expand(ab, new_len);
|
| 1257 | if (!avail)
|
| 1258 | return;
|
| 1259 | }
|
| 1260 | ptr = skb_tail_pointer(skb);
|
| 1261 | *ptr++ = '"';
|
| 1262 | memcpy(ptr, string, slen);
|
| 1263 | ptr += slen;
|
| 1264 | *ptr++ = '"';
|
| 1265 | *ptr = 0;
|
| 1266 | skb_put(skb, slen + 2);
|
| 1267 | }
|
| 1268 |
|
| 1269 | |
| 1270 | * audit_log_n_untrustedstring - log a string that may contain random characters
|
| 1271 | * @ab: audit_buffer
|
| 1272 | * @len: lenth of string (not including trailing null)
|
| 1273 | * @string: string to be logged
|
| 1274 | *
|
| 1275 | * This code will escape a string that is passed to it if the string
|
| 1276 | * contains a control character, unprintable character, double quote mark,
|
| 1277 | * or a space. Unescaped strings will start and end with a double quote mark.
|
| 1278 | * Strings that are escaped are printed in hex (2 digits per char).
|
| 1279 | *
|
| 1280 | * The caller specifies the number of characters in the string to log, which may
|
| 1281 | * or may not be the entire string.
|
| 1282 |
|
| 1283 | const char *audit_log_n_untrustedstring(struct audit_buffer *ab, size_t len,
|
| 1284 | const char *string)
|
| 1285 | {
|
| 1286 | const unsigned char *p;
|
| 1287 |
|
| 1288 | for (p = string; p < (const unsigned char *)string + len && *p; p++) {
|
| 1289 | if (*p == '"' || *p < 0x21 || *p > 0x7f) {
|
| 1290 | audit_log_hex(ab, string, len);
|
| 1291 | return string + len + 1;
|
| 1292 | }
|
| 1293 | }
|
| 1294 | audit_log_n_string(ab, len, string);
|
| 1295 | return p + 1;
|
| 1296 | }
|
| 1297 |
|
| 1298 | |
| 1299 | * audit_log_untrustedstring - log a string that may contain random characters
|
| 1300 | * @ab: audit_buffer
|
| 1301 | * @string: string to be logged
|
| 1302 | *
|
| 1303 | * Same as audit_log_n_untrustedstring(), except that strlen is used to
|
| 1304 | * determine string length.
|
| 1305 |
|
| 1306 | const char *audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
|
| 1307 | {
|
| 1308 | return audit_log_n_untrustedstring(ab, strlen(string), string);
|
| 1309 | }
|
| 1310 |
|
| 1311 |
|
| 1312 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
|
| 1313 | struct dentry *dentry, struct vfsmount *vfsmnt)
|
| 1314 | {
|
| 1315 | char *p, *path;
|
| 1316 |
|
| 1317 | if (prefix)
|
| 1318 | audit_log_format(ab, " %s", prefix);
|
| 1319 |
|
| 1320 |
|
| 1321 | path = kmalloc(PATH_MAX+11, ab->gfp_mask);
|
| 1322 | if (!path) {
|
| 1323 | audit_log_format(ab, "<no memory>");
|
| 1324 | return;
|
| 1325 | }
|
| 1326 | p = d_path(dentry, vfsmnt, path, PATH_MAX+11);
|
| 1327 | if (IS_ERR(p)) {
|
| 1328 |
|
| 1329 | audit_log_format(ab, "<too long>");
|
| 1330 | } else
|
| 1331 | audit_log_untrustedstring(ab, p);
|
| 1332 | kfree(path);
|
| 1333 | }
|
| 1334 |
|
| 1335 | |
| 1336 | * audit_log_end - end one audit record
|
| 1337 | * @ab: the audit_buffer
|
| 1338 | *
|
| 1339 | * The netlink_* functions cannot be called inside an irq context, so
|
| 1340 | * the audit buffer is placed on a queue and a tasklet is scheduled to
|
| 1341 | * remove them from the queue outside the irq context. May be called in
|
| 1342 | * any context.
|
| 1343 |
|
| 1344 | void audit_log_end(struct audit_buffer *ab)
|
| 1345 | {
|
| 1346 | if (!ab)
|
| 1347 | return;
|
| 1348 | if (!audit_rate_check()) {
|
| 1349 | audit_log_lost("rate limit exceeded");
|
| 1350 | } else {
|
| 1351 | if (audit_pid) {
|
| 1352 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
|
| 1353 | nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
|
| 1354 | skb_queue_tail(&audit_skb_queue, ab->skb);
|
| 1355 | ab->skb = NULL;
|
| 1356 | wake_up_interruptible(&kauditd_wait);
|
| 1357 | } else {
|
| 1358 | printk(KERN_NOTICE "%s\n", ab->skb->data + NLMSG_SPACE(0));
|
| 1359 | }
|
| 1360 | }
|
| 1361 | audit_buffer_free(ab);
|
| 1362 | }
|
| 1363 |
|
| 1364 | |
| 1365 | * audit_log - Log an audit record
|
| 1366 | * @ctx: audit context
|
| 1367 | * @gfp_mask: type of allocation
|
| 1368 | * @type: audit message type
|
| 1369 | * @fmt: format string to use
|
| 1370 | * @...: variable parameters matching the format string
|
| 1371 | *
|
| 1372 | * This is a convenience function that calls audit_log_start,
|
| 1373 | * audit_log_vformat, and audit_log_end. It may be called
|
| 1374 | * in any context.
|
| 1375 |
|
| 1376 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
|
| 1377 | const char *fmt, ...)
|
| 1378 | {
|
| 1379 | struct audit_buffer *ab;
|
| 1380 | va_list args;
|
| 1381 |
|
| 1382 | ab = audit_log_start(ctx, gfp_mask, type);
|
| 1383 | if (ab) {
|
| 1384 | va_start(args, fmt);
|
| 1385 | audit_log_vformat(ab, fmt, args);
|
| 1386 | va_end(args);
|
| 1387 | audit_log_end(ab);
|
| 1388 | }
|
| 1389 | }
|
| 1390 |
|
| 1391 | EXPORT_SYMBOL(audit_log_start);
|
| 1392 | EXPORT_SYMBOL(audit_log_end);
|
| 1393 | EXPORT_SYMBOL(audit_log_format);
|
| 1394 | EXPORT_SYMBOL(audit_log);
|