| 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
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| 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 Security Modules.
|
| 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 |
|
| 43 |
|
| 44 | #include <linux/init.h>
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| 45 | #include <asm/types.h>
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| 46 | #include <linux/atomic.h>
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| 47 | #include <linux/mm.h>
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| 48 | #include <linux/export.h>
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| 49 | #include <linux/slab.h>
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| 50 | #include <linux/err.h>
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| 51 | #include <linux/kthread.h>
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| 52 |
|
| 53 | #include <linux/audit.h>
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| 54 |
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| 55 | #include <net/sock.h>
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| 56 | #include <net/netlink.h>
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| 57 | #include <linux/skbuff.h>
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| 58 | #ifdef CONFIG_SECURITY
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| 59 | #include <linux/security.h>
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| 60 | #endif
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| 61 | #include <linux/netlink.h>
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| 62 | #include <linux/freezer.h>
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| 63 | #include <linux/tty.h>
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| 64 |
|
| 65 | #include "audit.h"
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| 66 |
|
| 67 | |
| 68 | * (Initialization happens after skb_init is called.)
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| 69 | #define AUDIT_DISABLED -1
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| 70 | #define AUDIT_UNINITIALIZED 0
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| 71 | #define AUDIT_INITIALIZED 1
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| 72 | static int audit_initialized;
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| 73 |
|
| 74 | #define AUDIT_OFF 0
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| 75 | #define AUDIT_ON 1
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| 76 | #define AUDIT_LOCKED 2
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| 77 | int audit_enabled;
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| 78 | int audit_ever_enabled;
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| 79 |
|
| 80 | EXPORT_SYMBOL_GPL(audit_enabled);
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| 81 |
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| 82 |
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| 83 | static int audit_default;
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| 84 |
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| 85 |
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| 86 | static int audit_failure = AUDIT_FAIL_PRINTK;
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| 87 |
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| 88 | |
| 89 | * If audit records are to be written to the netlink socket, audit_pid
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| 90 | * contains the pid of the auditd process and audit_nlk_pid contains
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| 91 | * the pid to use to send netlink messages to that process.
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| 92 |
|
| 93 | int audit_pid;
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| 94 | static int audit_nlk_pid;
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| 95 |
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| 96 | |
| 97 | * to that number per second. This prevents DoS attacks, but results in
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| 98 | * audit records being dropped.
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| 99 | static int audit_rate_limit;
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| 100 |
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| 101 |
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| 102 | static int audit_backlog_limit = 64;
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| 103 | static int audit_backlog_wait_time = 60 * HZ;
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| 104 | static int audit_backlog_wait_overflow = 0;
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| 105 |
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| 106 |
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| 107 | uid_t audit_sig_uid = -1;
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| 108 | pid_t audit_sig_pid = -1;
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| 109 | u32 audit_sig_sid = 0;
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| 110 |
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| 111 | |
| 112 | 0) [suppressed in audit_alloc]
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| 113 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
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| 114 | 2) out of memory in audit_log_move [alloc_skb]
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| 115 | 3) suppressed due to audit_rate_limit
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| 116 | 4) suppressed due to audit_backlog_limit
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| 117 |
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| 118 | static atomic_t audit_lost = ATOMIC_INIT(0);
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| 119 |
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| 120 |
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| 121 | static struct sock *audit_sock;
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| 122 |
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| 123 |
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| 124 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
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| 125 |
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| 126 | |
| 127 | * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
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| 128 | * being placed on the freelist).
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| 129 | static DEFINE_SPINLOCK(audit_freelist_lock);
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| 130 | static int audit_freelist_count;
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| 131 | static LIST_HEAD(audit_freelist);
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| 132 |
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| 133 | static struct sk_buff_head audit_skb_queue;
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| 134 |
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| 135 | static struct sk_buff_head audit_skb_hold_queue;
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| 136 | static struct task_struct *kauditd_task;
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| 137 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
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| 138 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
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| 139 |
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| 140 |
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| 141 | DEFINE_MUTEX(audit_cmd_mutex);
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| 142 |
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| 143 | |
| 144 | * audit records. Since printk uses a 1024 byte buffer, this buffer
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| 145 | * should be at least that large.
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| 146 | #define AUDIT_BUFSIZ 1024
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| 147 |
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| 148 | |
| 149 | * audit_freelist. Doing so eliminates many kmalloc/kfree calls.
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| 150 | #define AUDIT_MAXFREE (2*NR_CPUS)
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| 151 |
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| 152 | |
| 153 | * locks briefly to get the record off the freelist or to allocate the
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| 154 | * buffer, and locks briefly to send the buffer to the netlink layer or
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| 155 | * to place it on a transmit queue. Multiple audit_buffers can be in
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| 156 | * use simultaneously.
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| 157 | struct audit_buffer {
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| 158 | struct list_head list;
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| 159 | struct sk_buff *skb;
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| 160 | struct audit_context *ctx;
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| 161 | gfp_t gfp_mask;
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| 162 | };
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| 163 |
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| 164 | struct audit_reply {
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| 165 | int pid;
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| 166 | struct sk_buff *skb;
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| 167 | };
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| 168 |
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| 169 | static void audit_set_pid(struct audit_buffer *ab, pid_t pid)
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| 170 | {
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| 171 | if (ab) {
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| 172 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
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| 173 | nlh->nlmsg_pid = pid;
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| 174 | }
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| 175 | }
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| 176 |
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| 177 | void audit_panic(const char *message)
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| 178 | {
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| 179 | switch (audit_failure)
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| 180 | {
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| 181 | case AUDIT_FAIL_SILENT:
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| 182 | break;
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| 183 | case AUDIT_FAIL_PRINTK:
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| 184 | if (printk_ratelimit())
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| 185 | printk(KERN_ERR "audit: %s\n", message);
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| 186 | break;
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| 187 | case AUDIT_FAIL_PANIC:
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| 188 |
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| 189 | if (audit_pid)
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| 190 | panic("audit: %s\n", message);
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| 191 | break;
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| 192 | }
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| 193 | }
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| 194 |
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| 195 | static inline int audit_rate_check(void)
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| 196 | {
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| 197 | static unsigned long last_check = 0;
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| 198 | static int messages = 0;
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| 199 | static DEFINE_SPINLOCK(lock);
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| 200 | unsigned long flags;
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| 201 | unsigned long now;
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| 202 | unsigned long elapsed;
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| 203 | int retval = 0;
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| 204 |
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| 205 | if (!audit_rate_limit) return 1;
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| 206 |
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| 207 | spin_lock_irqsave(&lock, flags);
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| 208 | if (++messages < audit_rate_limit) {
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| 209 | retval = 1;
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| 210 | } else {
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| 211 | now = jiffies;
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| 212 | elapsed = now - last_check;
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| 213 | if (elapsed > HZ) {
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| 214 | last_check = now;
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| 215 | messages = 0;
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| 216 | retval = 1;
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| 217 | }
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| 218 | }
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| 219 | spin_unlock_irqrestore(&lock, flags);
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| 220 |
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| 221 | return retval;
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| 222 | }
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| 223 |
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| 224 | |
| 225 | * audit_log_lost - conditionally log lost audit message event
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| 226 | * @message: the message stating reason for lost audit message
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| 227 | *
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| 228 | * Emit at least 1 message per second, even if audit_rate_check is
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| 229 | * throttling.
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| 230 | * Always increment the lost messages counter.
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| 231 |
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| 232 | void audit_log_lost(const char *message)
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| 233 | {
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| 234 | static unsigned long last_msg = 0;
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| 235 | static DEFINE_SPINLOCK(lock);
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| 236 | unsigned long flags;
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| 237 | unsigned long now;
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| 238 | int print;
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| 239 |
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| 240 | atomic_inc(&audit_lost);
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| 241 |
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| 242 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
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| 243 |
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| 244 | if (!print) {
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| 245 | spin_lock_irqsave(&lock, flags);
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| 246 | now = jiffies;
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| 247 | if (now - last_msg > HZ) {
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| 248 | print = 1;
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| 249 | last_msg = now;
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| 250 | }
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| 251 | spin_unlock_irqrestore(&lock, flags);
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| 252 | }
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| 253 |
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| 254 | if (print) {
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| 255 | if (printk_ratelimit())
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| 256 | printk(KERN_WARNING
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| 257 | "audit: audit_lost=%d audit_rate_limit=%d "
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| 258 | "audit_backlog_limit=%d\n",
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| 259 | atomic_read(&audit_lost),
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| 260 | audit_rate_limit,
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| 261 | audit_backlog_limit);
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| 262 | audit_panic(message);
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| 263 | }
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| 264 | }
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| 265 |
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| 266 | static int audit_log_config_change(char *function_name, int new, int old,
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| 267 | uid_t loginuid, u32 sessionid, u32 sid,
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| 268 | int allow_changes)
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| 269 | {
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| 270 | struct audit_buffer *ab;
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| 271 | int rc = 0;
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| 272 |
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| 273 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
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| 274 | audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new,
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| 275 | old, loginuid, sessionid);
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| 276 | if (sid) {
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| 277 | char *ctx = NULL;
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| 278 | u32 len;
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| 279 |
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| 280 | rc = security_secid_to_secctx(sid, &ctx, &len);
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| 281 | if (rc) {
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| 282 | audit_log_format(ab, " sid=%u", sid);
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| 283 | allow_changes = 0;
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| 284 | } else {
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| 285 | audit_log_format(ab, " subj=%s", ctx);
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| 286 | security_release_secctx(ctx, len);
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| 287 | }
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| 288 | }
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| 289 | audit_log_format(ab, " res=%d", allow_changes);
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| 290 | audit_log_end(ab);
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| 291 | return rc;
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| 292 | }
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| 293 |
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| 294 | static int audit_do_config_change(char *function_name, int *to_change,
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| 295 | int new, uid_t loginuid, u32 sessionid,
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| 296 | u32 sid)
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| 297 | {
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| 298 | int allow_changes, rc = 0, old = *to_change;
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| 299 |
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| 300 |
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| 301 | if (audit_enabled == AUDIT_LOCKED)
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| 302 | allow_changes = 0;
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| 303 | else
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| 304 | allow_changes = 1;
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| 305 |
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| 306 | if (audit_enabled != AUDIT_OFF) {
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| 307 | rc = audit_log_config_change(function_name, new, old, loginuid,
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| 308 | sessionid, sid, allow_changes);
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| 309 | if (rc)
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| 310 | allow_changes = 0;
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| 311 | }
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| 312 |
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| 313 |
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| 314 | if (allow_changes == 1)
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| 315 | *to_change = new;
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| 316 |
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| 317 | else if (rc == 0)
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| 318 | rc = -EPERM;
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| 319 | return rc;
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| 320 | }
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| 321 |
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| 322 | static int audit_set_rate_limit(int limit, uid_t loginuid, u32 sessionid,
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| 323 | u32 sid)
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| 324 | {
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| 325 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit,
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| 326 | limit, loginuid, sessionid, sid);
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| 327 | }
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| 328 |
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| 329 | static int audit_set_backlog_limit(int limit, uid_t loginuid, u32 sessionid,
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| 330 | u32 sid)
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| 331 | {
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| 332 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit,
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| 333 | limit, loginuid, sessionid, sid);
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| 334 | }
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| 335 |
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| 336 | static int audit_set_enabled(int state, uid_t loginuid, u32 sessionid, u32 sid)
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| 337 | {
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| 338 | int rc;
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| 339 | if (state < AUDIT_OFF || state > AUDIT_LOCKED)
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| 340 | return -EINVAL;
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| 341 |
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| 342 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state,
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| 343 | loginuid, sessionid, sid);
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| 344 |
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| 345 | if (!rc)
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| 346 | audit_ever_enabled |= !!state;
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| 347 |
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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 sessionid, u32 sid)
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| 352 | {
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| 353 | if (state != AUDIT_FAIL_SILENT
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| 354 | && state != AUDIT_FAIL_PRINTK
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| 355 | && state != AUDIT_FAIL_PANIC)
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| 356 | return -EINVAL;
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| 357 |
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| 358 | return audit_do_config_change("audit_failure", &audit_failure, state,
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| 359 | loginuid, sessionid, sid);
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| 360 | }
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| 361 |
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| 362 | |
| 363 | * Queue skbs to be sent to auditd when/if it comes back. These skbs should
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| 364 | * already have been sent via prink/syslog and so if these messages are dropped
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| 365 | * it is not a huge concern since we already passed the audit_log_lost()
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| 366 | * notification and stuff. This is just nice to get audit messages during
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| 367 | * boot before auditd is running or messages generated while auditd is stopped.
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| 368 | * This only holds messages is audit_default is set, aka booting with audit=1
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| 369 | * or building your kernel that way.
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| 370 |
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| 371 | static void audit_hold_skb(struct sk_buff *skb)
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| 372 | {
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| 373 | if (audit_default &&
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| 374 | skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit)
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| 375 | skb_queue_tail(&audit_skb_hold_queue, skb);
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| 376 | else
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| 377 | kfree_skb(skb);
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| 378 | }
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| 379 |
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| 380 | |
| 381 | * For one reason or another this nlh isn't getting delivered to the userspace
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| 382 | * audit daemon, just send it to printk.
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| 383 |
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| 384 | static void audit_printk_skb(struct sk_buff *skb)
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| 385 | {
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| 386 | struct nlmsghdr *nlh = nlmsg_hdr(skb);
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| 387 | char *data = NLMSG_DATA(nlh);
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| 388 |
|
| 389 | if (nlh->nlmsg_type != AUDIT_EOE) {
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| 390 | if (printk_ratelimit())
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| 391 | printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data);
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| 392 | else
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| 393 | audit_log_lost("printk limit exceeded\n");
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| 394 | }
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| 395 |
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| 396 | audit_hold_skb(skb);
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| 397 | }
|
| 398 |
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| 399 | static void kauditd_send_skb(struct sk_buff *skb)
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| 400 | {
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| 401 | int err;
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| 402 |
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| 403 | skb_get(skb);
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| 404 | err = netlink_unicast(audit_sock, skb, audit_nlk_pid, 0);
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| 405 | if (err < 0) {
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| 406 | BUG_ON(err != -ECONNREFUSED);
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| 407 | printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid);
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| 408 | audit_log_lost("auditd disappeared\n");
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| 409 | audit_pid = 0;
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| 410 |
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| 411 | audit_hold_skb(skb);
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| 412 | } else
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| 413 |
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| 414 | consume_skb(skb);
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| 415 | }
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| 416 |
|
| 417 | static int kauditd_thread(void *dummy)
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| 418 | {
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| 419 | struct sk_buff *skb;
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| 420 |
|
| 421 | set_freezable();
|
| 422 | while (!kthread_should_stop()) {
|
| 423 | |
| 424 | * if auditd just started drain the queue of messages already
|
| 425 | * sent to syslog/printk. remember loss here is ok. we already
|
| 426 | * called audit_log_lost() if it didn't go out normally. so the
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| 427 | * race between the skb_dequeue and the next check for audit_pid
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| 428 | * doesn't matter.
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| 429 | *
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| 430 | * if you ever find kauditd to be too slow we can get a perf win
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| 431 | * by doing our own locking and keeping better track if there
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| 432 | * are messages in this queue. I don't see the need now, but
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| 433 | * in 5 years when I want to play with this again I'll see this
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| 434 | * note and still have no friggin idea what i'm thinking today.
|
| 435 |
|
| 436 | if (audit_default && audit_pid) {
|
| 437 | skb = skb_dequeue(&audit_skb_hold_queue);
|
| 438 | if (unlikely(skb)) {
|
| 439 | while (skb && audit_pid) {
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| 440 | kauditd_send_skb(skb);
|
| 441 | skb = skb_dequeue(&audit_skb_hold_queue);
|
| 442 | }
|
| 443 | }
|
| 444 | }
|
| 445 |
|
| 446 | skb = skb_dequeue(&audit_skb_queue);
|
| 447 | wake_up(&audit_backlog_wait);
|
| 448 | if (skb) {
|
| 449 | if (audit_pid)
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| 450 | kauditd_send_skb(skb);
|
| 451 | else
|
| 452 | audit_printk_skb(skb);
|
| 453 | } else {
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| 454 | DECLARE_WAITQUEUE(wait, current);
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| 455 | set_current_state(TASK_INTERRUPTIBLE);
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| 456 | add_wait_queue(&kauditd_wait, &wait);
|
| 457 |
|
| 458 | if (!skb_queue_len(&audit_skb_queue)) {
|
| 459 | try_to_freeze();
|
| 460 | schedule();
|
| 461 | }
|
| 462 |
|
| 463 | __set_current_state(TASK_RUNNING);
|
| 464 | remove_wait_queue(&kauditd_wait, &wait);
|
| 465 | }
|
| 466 | }
|
| 467 | return 0;
|
| 468 | }
|
| 469 |
|
| 470 | static int audit_prepare_user_tty(pid_t pid, uid_t loginuid, u32 sessionid)
|
| 471 | {
|
| 472 | struct task_struct *tsk;
|
| 473 | int err;
|
| 474 |
|
| 475 | rcu_read_lock();
|
| 476 | tsk = find_task_by_vpid(pid);
|
| 477 | if (!tsk) {
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| 478 | rcu_read_unlock();
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| 479 | return -ESRCH;
|
| 480 | }
|
| 481 | get_task_struct(tsk);
|
| 482 | rcu_read_unlock();
|
| 483 | err = tty_audit_push_task(tsk, loginuid, sessionid);
|
| 484 | put_task_struct(tsk);
|
| 485 | return err;
|
| 486 | }
|
| 487 |
|
| 488 | int audit_send_list(void *_dest)
|
| 489 | {
|
| 490 | struct audit_netlink_list *dest = _dest;
|
| 491 | int pid = dest->pid;
|
| 492 | struct sk_buff *skb;
|
| 493 |
|
| 494 |
|
| 495 | mutex_lock(&audit_cmd_mutex);
|
| 496 | mutex_unlock(&audit_cmd_mutex);
|
| 497 |
|
| 498 | while ((skb = __skb_dequeue(&dest->q)) != NULL)
|
| 499 | netlink_unicast(audit_sock, skb, pid, 0);
|
| 500 |
|
| 501 | kfree(dest);
|
| 502 |
|
| 503 | return 0;
|
| 504 | }
|
| 505 |
|
| 506 | struct sk_buff *audit_make_reply(int pid, int seq, int type, int done,
|
| 507 | int multi, const void *payload, int size)
|
| 508 | {
|
| 509 | struct sk_buff *skb;
|
| 510 | struct nlmsghdr *nlh;
|
| 511 | void *data;
|
| 512 | int flags = multi ? NLM_F_MULTI : 0;
|
| 513 | int t = done ? NLMSG_DONE : type;
|
| 514 |
|
| 515 | skb = nlmsg_new(size, GFP_KERNEL);
|
| 516 | if (!skb)
|
| 517 | return NULL;
|
| 518 |
|
| 519 | nlh = NLMSG_NEW(skb, pid, seq, t, size, flags);
|
| 520 | data = NLMSG_DATA(nlh);
|
| 521 | memcpy(data, payload, size);
|
| 522 | return skb;
|
| 523 |
|
| 524 | nlmsg_failure:
|
| 525 | if (skb)
|
| 526 | kfree_skb(skb);
|
| 527 | return NULL;
|
| 528 | }
|
| 529 |
|
| 530 | static int audit_send_reply_thread(void *arg)
|
| 531 | {
|
| 532 | struct audit_reply *reply = (struct audit_reply *)arg;
|
| 533 |
|
| 534 | mutex_lock(&audit_cmd_mutex);
|
| 535 | mutex_unlock(&audit_cmd_mutex);
|
| 536 |
|
| 537 | |
| 538 | because our timeout is set to infinite.
|
| 539 | netlink_unicast(audit_sock, reply->skb, reply->pid, 0);
|
| 540 | kfree(reply);
|
| 541 | return 0;
|
| 542 | }
|
| 543 | |
| 544 | * audit_send_reply - send an audit reply message via netlink
|
| 545 | * @pid: process id to send reply to
|
| 546 | * @seq: sequence number
|
| 547 | * @type: audit message type
|
| 548 | * @done: done (last) flag
|
| 549 | * @multi: multi-part message flag
|
| 550 | * @payload: payload data
|
| 551 | * @size: payload size
|
| 552 | *
|
| 553 | * Allocates an skb, builds the netlink message, and sends it to the pid.
|
| 554 | * No failure notifications.
|
| 555 |
|
| 556 | static void audit_send_reply(int pid, int seq, int type, int done, int multi,
|
| 557 | const void *payload, int size)
|
| 558 | {
|
| 559 | struct sk_buff *skb;
|
| 560 | struct task_struct *tsk;
|
| 561 | struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
|
| 562 | GFP_KERNEL);
|
| 563 |
|
| 564 | if (!reply)
|
| 565 | return;
|
| 566 |
|
| 567 | skb = audit_make_reply(pid, seq, type, done, multi, payload, size);
|
| 568 | if (!skb)
|
| 569 | goto out;
|
| 570 |
|
| 571 | reply->pid = pid;
|
| 572 | reply->skb = skb;
|
| 573 |
|
| 574 | tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
|
| 575 | if (!IS_ERR(tsk))
|
| 576 | return;
|
| 577 | kfree_skb(skb);
|
| 578 | out:
|
| 579 | kfree(reply);
|
| 580 | }
|
| 581 |
|
| 582 | |
| 583 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
|
| 584 | * control messages.
|
| 585 |
|
| 586 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
|
| 587 | {
|
| 588 | int err = 0;
|
| 589 |
|
| 590 | switch (msg_type) {
|
| 591 | case AUDIT_GET:
|
| 592 | case AUDIT_LIST:
|
| 593 | case AUDIT_LIST_RULES:
|
| 594 | case AUDIT_SET:
|
| 595 | case AUDIT_ADD:
|
| 596 | case AUDIT_ADD_RULE:
|
| 597 | case AUDIT_DEL:
|
| 598 | case AUDIT_DEL_RULE:
|
| 599 | case AUDIT_SIGNAL_INFO:
|
| 600 | case AUDIT_TTY_GET:
|
| 601 | case AUDIT_TTY_SET:
|
| 602 | case AUDIT_TRIM:
|
| 603 | case AUDIT_MAKE_EQUIV:
|
| 604 | if (!capable(CAP_AUDIT_CONTROL))
|
| 605 | err = -EPERM;
|
| 606 | break;
|
| 607 | case AUDIT_USER:
|
| 608 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 609 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 610 | if (!capable(CAP_AUDIT_WRITE))
|
| 611 | err = -EPERM;
|
| 612 | break;
|
| 613 | default:
|
| 614 | err = -EINVAL;
|
| 615 | }
|
| 616 |
|
| 617 | return err;
|
| 618 | }
|
| 619 |
|
| 620 | static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type,
|
| 621 | u32 pid, u32 uid, uid_t auid, u32 ses,
|
| 622 | u32 sid)
|
| 623 | {
|
| 624 | int rc = 0;
|
| 625 | char *ctx = NULL;
|
| 626 | u32 len;
|
| 627 |
|
| 628 | if (!audit_enabled) {
|
| 629 | *ab = NULL;
|
| 630 | return rc;
|
| 631 | }
|
| 632 |
|
| 633 | *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
|
| 634 | audit_log_format(*ab, "pid=%d uid=%u auid=%u ses=%u",
|
| 635 | pid, uid, auid, ses);
|
| 636 | if (sid) {
|
| 637 | rc = security_secid_to_secctx(sid, &ctx, &len);
|
| 638 | if (rc)
|
| 639 | audit_log_format(*ab, " ssid=%u", sid);
|
| 640 | else {
|
| 641 | audit_log_format(*ab, " subj=%s", ctx);
|
| 642 | security_release_secctx(ctx, len);
|
| 643 | }
|
| 644 | }
|
| 645 |
|
| 646 | return rc;
|
| 647 | }
|
| 648 |
|
| 649 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
| 650 | {
|
| 651 | u32 uid, pid, seq, sid;
|
| 652 | void *data;
|
| 653 | struct audit_status *status_get, status_set;
|
| 654 | int err;
|
| 655 | struct audit_buffer *ab;
|
| 656 | u16 msg_type = nlh->nlmsg_type;
|
| 657 | uid_t loginuid;
|
| 658 | u32 sessionid;
|
| 659 | struct audit_sig_info *sig_data;
|
| 660 | char *ctx = NULL;
|
| 661 | u32 len;
|
| 662 |
|
| 663 | err = audit_netlink_ok(skb, msg_type);
|
| 664 | if (err)
|
| 665 | return err;
|
| 666 |
|
| 667 | |
| 668 | * start kauditd to talk to it
|
| 669 | if (!kauditd_task)
|
| 670 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
|
| 671 | if (IS_ERR(kauditd_task)) {
|
| 672 | err = PTR_ERR(kauditd_task);
|
| 673 | kauditd_task = NULL;
|
| 674 | return err;
|
| 675 | }
|
| 676 |
|
| 677 | pid = NETLINK_CREDS(skb)->pid;
|
| 678 | uid = NETLINK_CREDS(skb)->uid;
|
| 679 | loginuid = audit_get_loginuid(current);
|
| 680 | sessionid = audit_get_sessionid(current);
|
| 681 | security_task_getsecid(current, &sid);
|
| 682 | seq = nlh->nlmsg_seq;
|
| 683 | data = NLMSG_DATA(nlh);
|
| 684 |
|
| 685 | switch (msg_type) {
|
| 686 | case AUDIT_GET:
|
| 687 | status_set.enabled = audit_enabled;
|
| 688 | status_set.failure = audit_failure;
|
| 689 | status_set.pid = audit_pid;
|
| 690 | status_set.rate_limit = audit_rate_limit;
|
| 691 | status_set.backlog_limit = audit_backlog_limit;
|
| 692 | status_set.lost = atomic_read(&audit_lost);
|
| 693 | status_set.backlog = skb_queue_len(&audit_skb_queue);
|
| 694 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0,
|
| 695 | &status_set, sizeof(status_set));
|
| 696 | break;
|
| 697 | case AUDIT_SET:
|
| 698 | if (nlh->nlmsg_len < sizeof(struct audit_status))
|
| 699 | return -EINVAL;
|
| 700 | status_get = (struct audit_status *)data;
|
| 701 | if (status_get->mask & AUDIT_STATUS_ENABLED) {
|
| 702 | err = audit_set_enabled(status_get->enabled,
|
| 703 | loginuid, sessionid, sid);
|
| 704 | if (err < 0)
|
| 705 | return err;
|
| 706 | }
|
| 707 | if (status_get->mask & AUDIT_STATUS_FAILURE) {
|
| 708 | err = audit_set_failure(status_get->failure,
|
| 709 | loginuid, sessionid, sid);
|
| 710 | if (err < 0)
|
| 711 | return err;
|
| 712 | }
|
| 713 | if (status_get->mask & AUDIT_STATUS_PID) {
|
| 714 | int new_pid = status_get->pid;
|
| 715 |
|
| 716 | if (audit_enabled != AUDIT_OFF)
|
| 717 | audit_log_config_change("audit_pid", new_pid,
|
| 718 | audit_pid, loginuid,
|
| 719 | sessionid, sid, 1);
|
| 720 |
|
| 721 | audit_pid = new_pid;
|
| 722 | audit_nlk_pid = NETLINK_CB(skb).pid;
|
| 723 | }
|
| 724 | if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) {
|
| 725 | err = audit_set_rate_limit(status_get->rate_limit,
|
| 726 | loginuid, sessionid, sid);
|
| 727 | if (err < 0)
|
| 728 | return err;
|
| 729 | }
|
| 730 | if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT)
|
| 731 | err = audit_set_backlog_limit(status_get->backlog_limit,
|
| 732 | loginuid, sessionid, sid);
|
| 733 | break;
|
| 734 | case AUDIT_USER:
|
| 735 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 736 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 737 | if (!audit_enabled && msg_type != AUDIT_USER_AVC)
|
| 738 | return 0;
|
| 739 |
|
| 740 | err = audit_filter_user(&NETLINK_CB(skb));
|
| 741 | if (err == 1) {
|
| 742 | err = 0;
|
| 743 | if (msg_type == AUDIT_USER_TTY) {
|
| 744 | err = audit_prepare_user_tty(pid, loginuid,
|
| 745 | sessionid);
|
| 746 | if (err)
|
| 747 | break;
|
| 748 | }
|
| 749 | audit_log_common_recv_msg(&ab, msg_type, pid, uid,
|
| 750 | loginuid, sessionid, sid);
|
| 751 |
|
| 752 | if (msg_type != AUDIT_USER_TTY)
|
| 753 | audit_log_format(ab, " msg='%.1024s'",
|
| 754 | (char *)data);
|
| 755 | else {
|
| 756 | int size;
|
| 757 |
|
| 758 | audit_log_format(ab, " msg=");
|
| 759 | size = nlmsg_len(nlh);
|
| 760 | if (size > 0 &&
|
| 761 | ((unsigned char *)data)[size - 1] == '\0')
|
| 762 | size--;
|
| 763 | audit_log_n_untrustedstring(ab, data, size);
|
| 764 | }
|
| 765 | audit_set_pid(ab, pid);
|
| 766 | audit_log_end(ab);
|
| 767 | }
|
| 768 | break;
|
| 769 | case AUDIT_ADD:
|
| 770 | case AUDIT_DEL:
|
| 771 | if (nlmsg_len(nlh) < sizeof(struct audit_rule))
|
| 772 | return -EINVAL;
|
| 773 | if (audit_enabled == AUDIT_LOCKED) {
|
| 774 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
|
| 775 | uid, loginuid, sessionid, sid);
|
| 776 |
|
| 777 | audit_log_format(ab, " audit_enabled=%d res=0",
|
| 778 | audit_enabled);
|
| 779 | audit_log_end(ab);
|
| 780 | return -EPERM;
|
| 781 | }
|
| 782 |
|
| 783 | case AUDIT_LIST:
|
| 784 | err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
|
| 785 | uid, seq, data, nlmsg_len(nlh),
|
| 786 | loginuid, sessionid, sid);
|
| 787 | break;
|
| 788 | case AUDIT_ADD_RULE:
|
| 789 | case AUDIT_DEL_RULE:
|
| 790 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
|
| 791 | return -EINVAL;
|
| 792 | if (audit_enabled == AUDIT_LOCKED) {
|
| 793 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
|
| 794 | uid, loginuid, sessionid, sid);
|
| 795 |
|
| 796 | audit_log_format(ab, " audit_enabled=%d res=0",
|
| 797 | audit_enabled);
|
| 798 | audit_log_end(ab);
|
| 799 | return -EPERM;
|
| 800 | }
|
| 801 |
|
| 802 | case AUDIT_LIST_RULES:
|
| 803 | err = audit_receive_filter(msg_type, NETLINK_CB(skb).pid,
|
| 804 | uid, seq, data, nlmsg_len(nlh),
|
| 805 | loginuid, sessionid, sid);
|
| 806 | break;
|
| 807 | case AUDIT_TRIM:
|
| 808 | audit_trim_trees();
|
| 809 |
|
| 810 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
|
| 811 | uid, loginuid, sessionid, sid);
|
| 812 |
|
| 813 | audit_log_format(ab, " op=trim res=1");
|
| 814 | audit_log_end(ab);
|
| 815 | break;
|
| 816 | case AUDIT_MAKE_EQUIV: {
|
| 817 | void *bufp = data;
|
| 818 | u32 sizes[2];
|
| 819 | size_t msglen = nlmsg_len(nlh);
|
| 820 | char *old, *new;
|
| 821 |
|
| 822 | err = -EINVAL;
|
| 823 | if (msglen < 2 * sizeof(u32))
|
| 824 | break;
|
| 825 | memcpy(sizes, bufp, 2 * sizeof(u32));
|
| 826 | bufp += 2 * sizeof(u32);
|
| 827 | msglen -= 2 * sizeof(u32);
|
| 828 | old = audit_unpack_string(&bufp, &msglen, sizes[0]);
|
| 829 | if (IS_ERR(old)) {
|
| 830 | err = PTR_ERR(old);
|
| 831 | break;
|
| 832 | }
|
| 833 | new = audit_unpack_string(&bufp, &msglen, sizes[1]);
|
| 834 | if (IS_ERR(new)) {
|
| 835 | err = PTR_ERR(new);
|
| 836 | kfree(old);
|
| 837 | break;
|
| 838 | }
|
| 839 |
|
| 840 | err = audit_tag_tree(old, new);
|
| 841 |
|
| 842 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE, pid,
|
| 843 | uid, loginuid, sessionid, sid);
|
| 844 |
|
| 845 | audit_log_format(ab, " op=make_equiv old=");
|
| 846 | audit_log_untrustedstring(ab, old);
|
| 847 | audit_log_format(ab, " new=");
|
| 848 | audit_log_untrustedstring(ab, new);
|
| 849 | audit_log_format(ab, " res=%d", !err);
|
| 850 | audit_log_end(ab);
|
| 851 | kfree(old);
|
| 852 | kfree(new);
|
| 853 | break;
|
| 854 | }
|
| 855 | case AUDIT_SIGNAL_INFO:
|
| 856 | len = 0;
|
| 857 | if (audit_sig_sid) {
|
| 858 | err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
|
| 859 | if (err)
|
| 860 | return err;
|
| 861 | }
|
| 862 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
|
| 863 | if (!sig_data) {
|
| 864 | if (audit_sig_sid)
|
| 865 | security_release_secctx(ctx, len);
|
| 866 | return -ENOMEM;
|
| 867 | }
|
| 868 | sig_data->uid = audit_sig_uid;
|
| 869 | sig_data->pid = audit_sig_pid;
|
| 870 | if (audit_sig_sid) {
|
| 871 | memcpy(sig_data->ctx, ctx, len);
|
| 872 | security_release_secctx(ctx, len);
|
| 873 | }
|
| 874 | audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_SIGNAL_INFO,
|
| 875 | 0, 0, sig_data, sizeof(*sig_data) + len);
|
| 876 | kfree(sig_data);
|
| 877 | break;
|
| 878 | case AUDIT_TTY_GET: {
|
| 879 | struct audit_tty_status s;
|
| 880 | struct task_struct *tsk;
|
| 881 | unsigned long flags;
|
| 882 |
|
| 883 | rcu_read_lock();
|
| 884 | tsk = find_task_by_vpid(pid);
|
| 885 | if (tsk && lock_task_sighand(tsk, &flags)) {
|
| 886 | s.enabled = tsk->signal->audit_tty != 0;
|
| 887 | unlock_task_sighand(tsk, &flags);
|
| 888 | } else
|
| 889 | err = -ESRCH;
|
| 890 | rcu_read_unlock();
|
| 891 |
|
| 892 | if (!err)
|
| 893 | audit_send_reply(NETLINK_CB(skb).pid, seq,
|
| 894 | AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
|
| 895 | break;
|
| 896 | }
|
| 897 | case AUDIT_TTY_SET: {
|
| 898 | struct audit_tty_status *s;
|
| 899 | struct task_struct *tsk;
|
| 900 | unsigned long flags;
|
| 901 |
|
| 902 | if (nlh->nlmsg_len < sizeof(struct audit_tty_status))
|
| 903 | return -EINVAL;
|
| 904 | s = data;
|
| 905 | if (s->enabled != 0 && s->enabled != 1)
|
| 906 | return -EINVAL;
|
| 907 | rcu_read_lock();
|
| 908 | tsk = find_task_by_vpid(pid);
|
| 909 | if (tsk && lock_task_sighand(tsk, &flags)) {
|
| 910 | tsk->signal->audit_tty = s->enabled != 0;
|
| 911 | unlock_task_sighand(tsk, &flags);
|
| 912 | } else
|
| 913 | err = -ESRCH;
|
| 914 | rcu_read_unlock();
|
| 915 | break;
|
| 916 | }
|
| 917 | default:
|
| 918 | err = -EINVAL;
|
| 919 | break;
|
| 920 | }
|
| 921 |
|
| 922 | return err < 0 ? err : 0;
|
| 923 | }
|
| 924 |
|
| 925 | |
| 926 | * Get message from skb. Each message is processed by audit_receive_msg.
|
| 927 | * Malformed skbs with wrong length are discarded silently.
|
| 928 |
|
| 929 | static void audit_receive_skb(struct sk_buff *skb)
|
| 930 | {
|
| 931 | struct nlmsghdr *nlh;
|
| 932 | |
| 933 | * len MUST be signed for NLMSG_NEXT to be able to dec it below 0
|
| 934 | * if the nlmsg_len was not aligned
|
| 935 |
|
| 936 | int len;
|
| 937 | int err;
|
| 938 |
|
| 939 | nlh = nlmsg_hdr(skb);
|
| 940 | len = skb->len;
|
| 941 |
|
| 942 | while (NLMSG_OK(nlh, len)) {
|
| 943 | err = audit_receive_msg(skb, nlh);
|
| 944 |
|
| 945 | if (err || (nlh->nlmsg_flags & NLM_F_ACK))
|
| 946 | netlink_ack(skb, nlh, err);
|
| 947 |
|
| 948 | nlh = NLMSG_NEXT(nlh, len);
|
| 949 | }
|
| 950 | }
|
| 951 |
|
| 952 |
|
| 953 | static void audit_receive(struct sk_buff *skb)
|
| 954 | {
|
| 955 | mutex_lock(&audit_cmd_mutex);
|
| 956 | audit_receive_skb(skb);
|
| 957 | mutex_unlock(&audit_cmd_mutex);
|
| 958 | }
|
| 959 |
|
| 960 |
|
| 961 | static int __init audit_init(void)
|
| 962 | {
|
| 963 | int i;
|
| 964 |
|
| 965 | if (audit_initialized == AUDIT_DISABLED)
|
| 966 | return 0;
|
| 967 |
|
| 968 | printk(KERN_INFO "audit: initializing netlink socket (%s)\n",
|
| 969 | audit_default ? "enabled" : "disabled");
|
| 970 | audit_sock = netlink_kernel_create(&init_net, NETLINK_AUDIT, 0,
|
| 971 | audit_receive, NULL, THIS_MODULE);
|
| 972 | if (!audit_sock)
|
| 973 | audit_panic("cannot initialize netlink socket");
|
| 974 | else
|
| 975 | audit_sock->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
|
| 976 |
|
| 977 | skb_queue_head_init(&audit_skb_queue);
|
| 978 | skb_queue_head_init(&audit_skb_hold_queue);
|
| 979 | audit_initialized = AUDIT_INITIALIZED;
|
| 980 | audit_enabled = audit_default;
|
| 981 | audit_ever_enabled |= !!audit_default;
|
| 982 |
|
| 983 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
|
| 984 |
|
| 985 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
|
| 986 | INIT_LIST_HEAD(&audit_inode_hash[i]);
|
| 987 |
|
| 988 | return 0;
|
| 989 | }
|
| 990 | __initcall(audit_init);
|
| 991 |
|
| 992 |
|
| 993 | static int __init audit_enable(char *str)
|
| 994 | {
|
| 995 | audit_default = !!simple_strtol(str, NULL, 0);
|
| 996 | if (!audit_default)
|
| 997 | audit_initialized = AUDIT_DISABLED;
|
| 998 |
|
| 999 | printk(KERN_INFO "audit: %s", audit_default ? "enabled" : "disabled");
|
| 1000 |
|
| 1001 | if (audit_initialized == AUDIT_INITIALIZED) {
|
| 1002 | audit_enabled = audit_default;
|
| 1003 | audit_ever_enabled |= !!audit_default;
|
| 1004 | } else if (audit_initialized == AUDIT_UNINITIALIZED) {
|
| 1005 | printk(" (after initialization)");
|
| 1006 | } else {
|
| 1007 | printk(" (until reboot)");
|
| 1008 | }
|
| 1009 | printk("\n");
|
| 1010 |
|
| 1011 | return 1;
|
| 1012 | }
|
| 1013 |
|
| 1014 | __setup("audit=", audit_enable);
|
| 1015 |
|
| 1016 | static void audit_buffer_free(struct audit_buffer *ab)
|
| 1017 | {
|
| 1018 | unsigned long flags;
|
| 1019 |
|
| 1020 | if (!ab)
|
| 1021 | return;
|
| 1022 |
|
| 1023 | if (ab->skb)
|
| 1024 | kfree_skb(ab->skb);
|
| 1025 |
|
| 1026 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 1027 | if (audit_freelist_count > AUDIT_MAXFREE)
|
| 1028 | kfree(ab);
|
| 1029 | else {
|
| 1030 | audit_freelist_count++;
|
| 1031 | list_add(&ab->list, &audit_freelist);
|
| 1032 | }
|
| 1033 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 1034 | }
|
| 1035 |
|
| 1036 | static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
|
| 1037 | gfp_t gfp_mask, int type)
|
| 1038 | {
|
| 1039 | unsigned long flags;
|
| 1040 | struct audit_buffer *ab = NULL;
|
| 1041 | struct nlmsghdr *nlh;
|
| 1042 |
|
| 1043 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 1044 | if (!list_empty(&audit_freelist)) {
|
| 1045 | ab = list_entry(audit_freelist.next,
|
| 1046 | struct audit_buffer, list);
|
| 1047 | list_del(&ab->list);
|
| 1048 | --audit_freelist_count;
|
| 1049 | }
|
| 1050 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 1051 |
|
| 1052 | if (!ab) {
|
| 1053 | ab = kmalloc(sizeof(*ab), gfp_mask);
|
| 1054 | if (!ab)
|
| 1055 | goto err;
|
| 1056 | }
|
| 1057 |
|
| 1058 | ab->ctx = ctx;
|
| 1059 | ab->gfp_mask = gfp_mask;
|
| 1060 |
|
| 1061 | ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
|
| 1062 | if (!ab->skb)
|
| 1063 | goto nlmsg_failure;
|
| 1064 |
|
| 1065 | nlh = NLMSG_NEW(ab->skb, 0, 0, type, 0, 0);
|
| 1066 |
|
| 1067 | return ab;
|
| 1068 |
|
| 1069 | nlmsg_failure:
|
| 1070 | kfree_skb(ab->skb);
|
| 1071 | ab->skb = NULL;
|
| 1072 | err:
|
| 1073 | audit_buffer_free(ab);
|
| 1074 | return NULL;
|
| 1075 | }
|
| 1076 |
|
| 1077 | |
| 1078 | * audit_serial - compute a serial number for the audit record
|
| 1079 | *
|
| 1080 | * Compute a serial number for the audit record. Audit records are
|
| 1081 | * written to user-space as soon as they are generated, so a complete
|
| 1082 | * audit record may be written in several pieces. The timestamp of the
|
| 1083 | * record and this serial number are used by the user-space tools to
|
| 1084 | * determine which pieces belong to the same audit record. The
|
| 1085 | * (timestamp,serial) tuple is unique for each syscall and is live from
|
| 1086 | * syscall entry to syscall exit.
|
| 1087 | *
|
| 1088 | * NOTE: Another possibility is to store the formatted records off the
|
| 1089 | * audit context (for those records that have a context), and emit them
|
| 1090 | * all at syscall exit. However, this could delay the reporting of
|
| 1091 | * significant errors until syscall exit (or never, if the system
|
| 1092 | * halts).
|
| 1093 |
|
| 1094 | unsigned int audit_serial(void)
|
| 1095 | {
|
| 1096 | static DEFINE_SPINLOCK(serial_lock);
|
| 1097 | static unsigned int serial = 0;
|
| 1098 |
|
| 1099 | unsigned long flags;
|
| 1100 | unsigned int ret;
|
| 1101 |
|
| 1102 | spin_lock_irqsave(&serial_lock, flags);
|
| 1103 | do {
|
| 1104 | ret = ++serial;
|
| 1105 | } while (unlikely(!ret));
|
| 1106 | spin_unlock_irqrestore(&serial_lock, flags);
|
| 1107 |
|
| 1108 | return ret;
|
| 1109 | }
|
| 1110 |
|
| 1111 | static inline void audit_get_stamp(struct audit_context *ctx,
|
| 1112 | struct timespec *t, unsigned int *serial)
|
| 1113 | {
|
| 1114 | if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
|
| 1115 | *t = CURRENT_TIME;
|
| 1116 | *serial = audit_serial();
|
| 1117 | }
|
| 1118 | }
|
| 1119 |
|
| 1120 | |
| 1121 | * audit buffer, but then no locking is required for calls to
|
| 1122 | * audit_log_*format. If the tsk is a task that is currently in a
|
| 1123 | * syscall, then the syscall is marked as auditable and an audit record
|
| 1124 | * will be written at syscall exit. If there is no associated task, tsk
|
| 1125 | * should be NULL.
|
| 1126 |
|
| 1127 | |
| 1128 | * audit_log_start - obtain an audit buffer
|
| 1129 | * @ctx: audit_context (may be NULL)
|
| 1130 | * @gfp_mask: type of allocation
|
| 1131 | * @type: audit message type
|
| 1132 | *
|
| 1133 | * Returns audit_buffer pointer on success or NULL on error.
|
| 1134 | *
|
| 1135 | * Obtain an audit buffer. This routine does locking to obtain the
|
| 1136 | * audit buffer, but then no locking is required for calls to
|
| 1137 | * audit_log_*format. If the task (ctx) is a task that is currently in a
|
| 1138 | * syscall, then the syscall is marked as auditable and an audit record
|
| 1139 | * will be written at syscall exit. If there is no associated task, then
|
| 1140 | * task context (ctx) should be NULL.
|
| 1141 |
|
| 1142 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
|
| 1143 | int type)
|
| 1144 | {
|
| 1145 | struct audit_buffer *ab = NULL;
|
| 1146 | struct timespec t;
|
| 1147 | unsigned int uninitialized_var(serial);
|
| 1148 | int reserve;
|
| 1149 | unsigned long timeout_start = jiffies;
|
| 1150 |
|
| 1151 | if (audit_initialized != AUDIT_INITIALIZED)
|
| 1152 | return NULL;
|
| 1153 |
|
| 1154 | if (unlikely(audit_filter_type(type)))
|
| 1155 | return NULL;
|
| 1156 |
|
| 1157 | if (gfp_mask & __GFP_WAIT)
|
| 1158 | reserve = 0;
|
| 1159 | else
|
| 1160 | reserve = 5; |
| 1161 | entries over the normal backlog limit
|
| 1162 |
|
| 1163 | while (audit_backlog_limit
|
| 1164 | && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
|
| 1165 | if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time
|
| 1166 | && time_before(jiffies, timeout_start + audit_backlog_wait_time)) {
|
| 1167 |
|
| 1168 |
|
| 1169 | DECLARE_WAITQUEUE(wait, current);
|
| 1170 | set_current_state(TASK_INTERRUPTIBLE);
|
| 1171 | add_wait_queue(&audit_backlog_wait, &wait);
|
| 1172 |
|
| 1173 | if (audit_backlog_limit &&
|
| 1174 | skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
|
| 1175 | schedule_timeout(timeout_start + audit_backlog_wait_time - jiffies);
|
| 1176 |
|
| 1177 | __set_current_state(TASK_RUNNING);
|
| 1178 | remove_wait_queue(&audit_backlog_wait, &wait);
|
| 1179 | continue;
|
| 1180 | }
|
| 1181 | if (audit_rate_check() && printk_ratelimit())
|
| 1182 | printk(KERN_WARNING
|
| 1183 | "audit: audit_backlog=%d > "
|
| 1184 | "audit_backlog_limit=%d\n",
|
| 1185 | skb_queue_len(&audit_skb_queue),
|
| 1186 | audit_backlog_limit);
|
| 1187 | audit_log_lost("backlog limit exceeded");
|
| 1188 | audit_backlog_wait_time = audit_backlog_wait_overflow;
|
| 1189 | wake_up(&audit_backlog_wait);
|
| 1190 | return NULL;
|
| 1191 | }
|
| 1192 |
|
| 1193 | ab = audit_buffer_alloc(ctx, gfp_mask, type);
|
| 1194 | if (!ab) {
|
| 1195 | audit_log_lost("out of memory in audit_log_start");
|
| 1196 | return NULL;
|
| 1197 | }
|
| 1198 |
|
| 1199 | audit_get_stamp(ab->ctx, &t, &serial);
|
| 1200 |
|
| 1201 | audit_log_format(ab, "audit(%lu.%03lu:%u): ",
|
| 1202 | t.tv_sec, t.tv_nsec/1000000, serial);
|
| 1203 | return ab;
|
| 1204 | }
|
| 1205 |
|
| 1206 | |
| 1207 | * audit_expand - expand skb in the audit buffer
|
| 1208 | * @ab: audit_buffer
|
| 1209 | * @extra: space to add at tail of the skb
|
| 1210 | *
|
| 1211 | * Returns 0 (no space) on failed expansion, or available space if
|
| 1212 | * successful.
|
| 1213 |
|
| 1214 | static inline int audit_expand(struct audit_buffer *ab, int extra)
|
| 1215 | {
|
| 1216 | struct sk_buff *skb = ab->skb;
|
| 1217 | int oldtail = skb_tailroom(skb);
|
| 1218 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
|
| 1219 | int newtail = skb_tailroom(skb);
|
| 1220 |
|
| 1221 | if (ret < 0) {
|
| 1222 | audit_log_lost("out of memory in audit_expand");
|
| 1223 | return 0;
|
| 1224 | }
|
| 1225 |
|
| 1226 | skb->truesize += newtail - oldtail;
|
| 1227 | return newtail;
|
| 1228 | }
|
| 1229 |
|
| 1230 | |
| 1231 | * Format an audit message into the audit buffer. If there isn't enough
|
| 1232 | * room in the audit buffer, more room will be allocated and vsnprint
|
| 1233 | * will be called a second time. Currently, we assume that a printk
|
| 1234 | * can't format message larger than 1024 bytes, so we don't either.
|
| 1235 |
|
| 1236 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
|
| 1237 | va_list args)
|
| 1238 | {
|
| 1239 | int len, avail;
|
| 1240 | struct sk_buff *skb;
|
| 1241 | va_list args2;
|
| 1242 |
|
| 1243 | if (!ab)
|
| 1244 | return;
|
| 1245 |
|
| 1246 | BUG_ON(!ab->skb);
|
| 1247 | skb = ab->skb;
|
| 1248 | avail = skb_tailroom(skb);
|
| 1249 | if (avail == 0) {
|
| 1250 | avail = audit_expand(ab, AUDIT_BUFSIZ);
|
| 1251 | if (!avail)
|
| 1252 | goto out;
|
| 1253 | }
|
| 1254 | va_copy(args2, args);
|
| 1255 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
|
| 1256 | if (len >= avail) {
|
| 1257 | |
| 1258 | * here and AUDIT_BUFSIZ is at least 1024, then we can
|
| 1259 | * log everything that printk could have logged.
|
| 1260 | avail = audit_expand(ab,
|
| 1261 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
|
| 1262 | if (!avail)
|
| 1263 | goto out_va_end;
|
| 1264 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
|
| 1265 | }
|
| 1266 | if (len > 0)
|
| 1267 | skb_put(skb, len);
|
| 1268 | out_va_end:
|
| 1269 | va_end(args2);
|
| 1270 | out:
|
| 1271 | return;
|
| 1272 | }
|
| 1273 |
|
| 1274 | |
| 1275 | * audit_log_format - format a message into the audit buffer.
|
| 1276 | * @ab: audit_buffer
|
| 1277 | * @fmt: format string
|
| 1278 | * @...: optional parameters matching @fmt string
|
| 1279 | *
|
| 1280 | * All the work is done in audit_log_vformat.
|
| 1281 |
|
| 1282 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
|
| 1283 | {
|
| 1284 | va_list args;
|
| 1285 |
|
| 1286 | if (!ab)
|
| 1287 | return;
|
| 1288 | va_start(args, fmt);
|
| 1289 | audit_log_vformat(ab, fmt, args);
|
| 1290 | va_end(args);
|
| 1291 | }
|
| 1292 |
|
| 1293 | |
| 1294 | * audit_log_hex - convert a buffer to hex and append it to the audit skb
|
| 1295 | * @ab: the audit_buffer
|
| 1296 | * @buf: buffer to convert to hex
|
| 1297 | * @len: length of @buf to be converted
|
| 1298 | *
|
| 1299 | * No return value; failure to expand is silently ignored.
|
| 1300 | *
|
| 1301 | * This function will take the passed buf and convert it into a string of
|
| 1302 | * ascii hex digits. The new string is placed onto the skb.
|
| 1303 |
|
| 1304 | void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
|
| 1305 | size_t len)
|
| 1306 | {
|
| 1307 | int i, avail, new_len;
|
| 1308 | unsigned char *ptr;
|
| 1309 | struct sk_buff *skb;
|
| 1310 | static const unsigned char *hex = "0123456789ABCDEF";
|
| 1311 |
|
| 1312 | if (!ab)
|
| 1313 | return;
|
| 1314 |
|
| 1315 | BUG_ON(!ab->skb);
|
| 1316 | skb = ab->skb;
|
| 1317 | avail = skb_tailroom(skb);
|
| 1318 | new_len = len<<1;
|
| 1319 | if (new_len >= avail) {
|
| 1320 |
|
| 1321 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
|
| 1322 | avail = audit_expand(ab, new_len);
|
| 1323 | if (!avail)
|
| 1324 | return;
|
| 1325 | }
|
| 1326 |
|
| 1327 | ptr = skb_tail_pointer(skb);
|
| 1328 | for (i=0; i<len; i++) {
|
| 1329 | *ptr++ = hex[(buf[i] & 0xF0)>>4];
|
| 1330 | *ptr++ = hex[buf[i] & 0x0F];
|
| 1331 | }
|
| 1332 | *ptr = 0;
|
| 1333 | skb_put(skb, len << 1);
|
| 1334 | }
|
| 1335 |
|
| 1336 | |
| 1337 | * Format a string of no more than slen characters into the audit buffer,
|
| 1338 | * enclosed in quote marks.
|
| 1339 |
|
| 1340 | void audit_log_n_string(struct audit_buffer *ab, const char *string,
|
| 1341 | size_t slen)
|
| 1342 | {
|
| 1343 | int avail, new_len;
|
| 1344 | unsigned char *ptr;
|
| 1345 | struct sk_buff *skb;
|
| 1346 |
|
| 1347 | if (!ab)
|
| 1348 | return;
|
| 1349 |
|
| 1350 | BUG_ON(!ab->skb);
|
| 1351 | skb = ab->skb;
|
| 1352 | avail = skb_tailroom(skb);
|
| 1353 | new_len = slen + 3;
|
| 1354 | if (new_len > avail) {
|
| 1355 | avail = audit_expand(ab, new_len);
|
| 1356 | if (!avail)
|
| 1357 | return;
|
| 1358 | }
|
| 1359 | ptr = skb_tail_pointer(skb);
|
| 1360 | *ptr++ = '"';
|
| 1361 | memcpy(ptr, string, slen);
|
| 1362 | ptr += slen;
|
| 1363 | *ptr++ = '"';
|
| 1364 | *ptr = 0;
|
| 1365 | skb_put(skb, slen + 2);
|
| 1366 | }
|
| 1367 |
|
| 1368 | |
| 1369 | * audit_string_contains_control - does a string need to be logged in hex
|
| 1370 | * @string: string to be checked
|
| 1371 | * @len: max length of the string to check
|
| 1372 |
|
| 1373 | int audit_string_contains_control(const char *string, size_t len)
|
| 1374 | {
|
| 1375 | const unsigned char *p;
|
| 1376 | for (p = string; p < (const unsigned char *)string + len; p++) {
|
| 1377 | if (*p == '"' || *p < 0x21 || *p > 0x7e)
|
| 1378 | return 1;
|
| 1379 | }
|
| 1380 | return 0;
|
| 1381 | }
|
| 1382 |
|
| 1383 | |
| 1384 | * audit_log_n_untrustedstring - log a string that may contain random characters
|
| 1385 | * @ab: audit_buffer
|
| 1386 | * @len: length of string (not including trailing null)
|
| 1387 | * @string: string to be logged
|
| 1388 | *
|
| 1389 | * This code will escape a string that is passed to it if the string
|
| 1390 | * contains a control character, unprintable character, double quote mark,
|
| 1391 | * or a space. Unescaped strings will start and end with a double quote mark.
|
| 1392 | * Strings that are escaped are printed in hex (2 digits per char).
|
| 1393 | *
|
| 1394 | * The caller specifies the number of characters in the string to log, which may
|
| 1395 | * or may not be the entire string.
|
| 1396 |
|
| 1397 | void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
|
| 1398 | size_t len)
|
| 1399 | {
|
| 1400 | if (audit_string_contains_control(string, len))
|
| 1401 | audit_log_n_hex(ab, string, len);
|
| 1402 | else
|
| 1403 | audit_log_n_string(ab, string, len);
|
| 1404 | }
|
| 1405 |
|
| 1406 | |
| 1407 | * audit_log_untrustedstring - log a string that may contain random characters
|
| 1408 | * @ab: audit_buffer
|
| 1409 | * @string: string to be logged
|
| 1410 | *
|
| 1411 | * Same as audit_log_n_untrustedstring(), except that strlen is used to
|
| 1412 | * determine string length.
|
| 1413 |
|
| 1414 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
|
| 1415 | {
|
| 1416 | audit_log_n_untrustedstring(ab, string, strlen(string));
|
| 1417 | }
|
| 1418 |
|
| 1419 |
|
| 1420 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
|
| 1421 | const struct path *path)
|
| 1422 | {
|
| 1423 | char *p, *pathname;
|
| 1424 |
|
| 1425 | if (prefix)
|
| 1426 | audit_log_format(ab, "%s", prefix);
|
| 1427 |
|
| 1428 |
|
| 1429 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
|
| 1430 | if (!pathname) {
|
| 1431 | audit_log_string(ab, "<no_memory>");
|
| 1432 | return;
|
| 1433 | }
|
| 1434 | p = d_path(path, pathname, PATH_MAX+11);
|
| 1435 | if (IS_ERR(p)) {
|
| 1436 |
|
| 1437 | audit_log_string(ab, "<too_long>");
|
| 1438 | } else
|
| 1439 | audit_log_untrustedstring(ab, p);
|
| 1440 | kfree(pathname);
|
| 1441 | }
|
| 1442 |
|
| 1443 | void audit_log_key(struct audit_buffer *ab, char *key)
|
| 1444 | {
|
| 1445 | audit_log_format(ab, " key=");
|
| 1446 | if (key)
|
| 1447 | audit_log_untrustedstring(ab, key);
|
| 1448 | else
|
| 1449 | audit_log_format(ab, "(null)");
|
| 1450 | }
|
| 1451 |
|
| 1452 | |
| 1453 | * audit_log_end - end one audit record
|
| 1454 | * @ab: the audit_buffer
|
| 1455 | *
|
| 1456 | * The netlink_* functions cannot be called inside an irq context, so
|
| 1457 | * the audit buffer is placed on a queue and a tasklet is scheduled to
|
| 1458 | * remove them from the queue outside the irq context. May be called in
|
| 1459 | * any context.
|
| 1460 |
|
| 1461 | void audit_log_end(struct audit_buffer *ab)
|
| 1462 | {
|
| 1463 | if (!ab)
|
| 1464 | return;
|
| 1465 | if (!audit_rate_check()) {
|
| 1466 | audit_log_lost("rate limit exceeded");
|
| 1467 | } else {
|
| 1468 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
|
| 1469 | nlh->nlmsg_len = ab->skb->len - NLMSG_SPACE(0);
|
| 1470 |
|
| 1471 | if (audit_pid) {
|
| 1472 | skb_queue_tail(&audit_skb_queue, ab->skb);
|
| 1473 | wake_up_interruptible(&kauditd_wait);
|
| 1474 | } else {
|
| 1475 | audit_printk_skb(ab->skb);
|
| 1476 | }
|
| 1477 | ab->skb = NULL;
|
| 1478 | }
|
| 1479 | audit_buffer_free(ab);
|
| 1480 | }
|
| 1481 |
|
| 1482 | |
| 1483 | * audit_log - Log an audit record
|
| 1484 | * @ctx: audit context
|
| 1485 | * @gfp_mask: type of allocation
|
| 1486 | * @type: audit message type
|
| 1487 | * @fmt: format string to use
|
| 1488 | * @...: variable parameters matching the format string
|
| 1489 | *
|
| 1490 | * This is a convenience function that calls audit_log_start,
|
| 1491 | * audit_log_vformat, and audit_log_end. It may be called
|
| 1492 | * in any context.
|
| 1493 |
|
| 1494 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
|
| 1495 | const char *fmt, ...)
|
| 1496 | {
|
| 1497 | struct audit_buffer *ab;
|
| 1498 | va_list args;
|
| 1499 |
|
| 1500 | ab = audit_log_start(ctx, gfp_mask, type);
|
| 1501 | if (ab) {
|
| 1502 | va_start(args, fmt);
|
| 1503 | audit_log_vformat(ab, fmt, args);
|
| 1504 | va_end(args);
|
| 1505 | audit_log_end(ab);
|
| 1506 | }
|
| 1507 | }
|
| 1508 |
|
| 1509 | #ifdef CONFIG_SECURITY
|
| 1510 | |
| 1511 | * audit_log_secctx - Converts and logs SELinux context
|
| 1512 | * @ab: audit_buffer
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| 1513 | * @secid: security number
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| 1514 | *
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| 1515 | * This is a helper function that calls security_secid_to_secctx to convert
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| 1516 | * secid to secctx and then adds the (converted) SELinux context to the audit
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| 1517 | * log by calling audit_log_format, thus also preventing leak of internal secid
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| 1518 | * to userspace. If secid cannot be converted audit_panic is called.
|
| 1519 |
|
| 1520 | void audit_log_secctx(struct audit_buffer *ab, u32 secid)
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| 1521 | {
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| 1522 | u32 len;
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| 1523 | char *secctx;
|
| 1524 |
|
| 1525 | if (security_secid_to_secctx(secid, &secctx, &len)) {
|
| 1526 | audit_panic("Cannot convert secid to context");
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| 1527 | } else {
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| 1528 | audit_log_format(ab, " obj=%s", secctx);
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| 1529 | security_release_secctx(secctx, len);
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| 1530 | }
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| 1531 | }
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| 1532 | EXPORT_SYMBOL(audit_log_secctx);
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| 1533 | #endif
|
| 1534 |
|
| 1535 | EXPORT_SYMBOL(audit_log_start);
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| 1536 | EXPORT_SYMBOL(audit_log_end);
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| 1537 | EXPORT_SYMBOL(audit_log_format);
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| 1538 | EXPORT_SYMBOL(audit_log);
|