| 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
|
| 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
|
| 10 | * the Free Software Foundation; either version 2 of the License, or
|
| 11 | * (at your option) any later version.
|
| 12 | *
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| 13 | * This program is distributed in the hope that it will be useful,
|
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
| 16 | * GNU General Public License for more details.
|
| 17 | *
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| 18 | * You should have received a copy of the GNU General Public License
|
| 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
|
| 21 | *
|
| 22 | * Written by Rickard E. (Rik) Faith <[email protected]>
|
| 23 | *
|
| 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).
|
| 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.
|
| 33 | * 3) Ability to disable syscall auditing at boot time (audit=0).
|
| 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).
|
| 37 | * 5) Netlink interface to user-space.
|
| 38 | * 6) Support low-overhead kernel-based filtering to minimize the
|
| 39 | * information that must be passed to user-space.
|
| 40 | *
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| 41 | * Example user-space utilities: http://people.redhat.com/sgrubb/audit/
|
| 42 |
|
| 43 |
|
| 44 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
| 45 |
|
| 46 | #include <linux/file.h>
|
| 47 | #include <linux/init.h>
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| 48 | #include <linux/types.h>
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| 49 | #include <linux/atomic.h>
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| 50 | #include <linux/mm.h>
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| 51 | #include <linux/export.h>
|
| 52 | #include <linux/slab.h>
|
| 53 | #include <linux/err.h>
|
| 54 | #include <linux/kthread.h>
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| 55 | #include <linux/kernel.h>
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| 56 | #include <linux/syscalls.h>
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| 57 |
|
| 58 | #include <linux/audit.h>
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| 59 |
|
| 60 | #include <net/sock.h>
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| 61 | #include <net/netlink.h>
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| 62 | #include <linux/skbuff.h>
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| 63 | #ifdef CONFIG_SECURITY
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| 64 | #include <linux/security.h>
|
| 65 | #endif
|
| 66 | #include <linux/freezer.h>
|
| 67 | #include <linux/tty.h>
|
| 68 | #include <linux/pid_namespace.h>
|
| 69 | #include <net/netns/generic.h>
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| 70 |
|
| 71 | #include "audit.h"
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| 72 |
|
| 73 | |
| 74 | * (Initialization happens after skb_init is called.)
|
| 75 | #define AUDIT_DISABLED -1
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| 76 | #define AUDIT_UNINITIALIZED 0
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| 77 | #define AUDIT_INITIALIZED 1
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| 78 | static int audit_initialized;
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| 79 |
|
| 80 | #define AUDIT_OFF 0
|
| 81 | #define AUDIT_ON 1
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| 82 | #define AUDIT_LOCKED 2
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| 83 | u32 audit_enabled;
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| 84 | u32 audit_ever_enabled;
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| 85 |
|
| 86 | EXPORT_SYMBOL_GPL(audit_enabled);
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| 87 |
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| 88 |
|
| 89 | static u32 audit_default;
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| 90 |
|
| 91 |
|
| 92 | static u32 audit_failure = AUDIT_FAIL_PRINTK;
|
| 93 |
|
| 94 | |
| 95 | * If audit records are to be written to the netlink socket, audit_pid
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| 96 | * contains the pid of the auditd process and audit_nlk_portid contains
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| 97 | * the portid to use to send netlink messages to that process.
|
| 98 |
|
| 99 | int audit_pid;
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| 100 | static __u32 audit_nlk_portid;
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| 101 |
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| 102 | |
| 103 | * to that number per second. This prevents DoS attacks, but results in
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| 104 | * audit records being dropped.
|
| 105 | static u32 audit_rate_limit;
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| 106 |
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| 107 | |
| 108 | * When set to zero, this means unlimited.
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| 109 | static u32 audit_backlog_limit = 64;
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| 110 | #define AUDIT_BACKLOG_WAIT_TIME (60 * HZ)
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| 111 | static u32 audit_backlog_wait_time_master = AUDIT_BACKLOG_WAIT_TIME;
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| 112 | static u32 audit_backlog_wait_time = AUDIT_BACKLOG_WAIT_TIME;
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| 113 | static u32 audit_backlog_wait_overflow = 0;
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| 114 |
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| 115 |
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| 116 | kuid_t audit_sig_uid = INVALID_UID;
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| 117 | pid_t audit_sig_pid = -1;
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| 118 | u32 audit_sig_sid = 0;
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| 119 |
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| 120 | |
| 121 | 0) [suppressed in audit_alloc]
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| 122 | 1) out of memory in audit_log_start [kmalloc of struct audit_buffer]
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| 123 | 2) out of memory in audit_log_move [alloc_skb]
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| 124 | 3) suppressed due to audit_rate_limit
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| 125 | 4) suppressed due to audit_backlog_limit
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| 126 |
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| 127 | static atomic_t audit_lost = ATOMIC_INIT(0);
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| 128 |
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| 129 |
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| 130 | static struct sock *audit_sock;
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| 131 | static int audit_net_id;
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| 132 |
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| 133 |
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| 134 | struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS];
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| 135 |
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| 136 | |
| 137 | * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of
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| 138 | * being placed on the freelist).
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| 139 | static DEFINE_SPINLOCK(audit_freelist_lock);
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| 140 | static int audit_freelist_count;
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| 141 | static LIST_HEAD(audit_freelist);
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| 142 |
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| 143 | static struct sk_buff_head audit_skb_queue;
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| 144 |
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| 145 | static struct sk_buff_head audit_skb_hold_queue;
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| 146 | static struct task_struct *kauditd_task;
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| 147 | static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);
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| 148 | static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait);
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| 149 |
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| 150 | static struct audit_features af = {.vers = AUDIT_FEATURE_VERSION,
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| 151 | .mask = -1,
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| 152 | .features = 0,
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| 153 | .lock = 0,};
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| 154 |
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| 155 | static char *audit_feature_names[2] = {
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| 156 | "only_unset_loginuid",
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| 157 | "loginuid_immutable",
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| 158 | };
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| 159 |
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| 160 |
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| 161 |
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| 162 | DEFINE_MUTEX(audit_cmd_mutex);
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| 163 |
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| 164 | |
| 165 | * audit records. Since printk uses a 1024 byte buffer, this buffer
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| 166 | * should be at least that large.
|
| 167 | #define AUDIT_BUFSIZ 1024
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| 168 |
|
| 169 | |
| 170 | * audit_freelist. Doing so eliminates many kmalloc/kfree calls.
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| 171 | #define AUDIT_MAXFREE (2*NR_CPUS)
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| 172 |
|
| 173 | |
| 174 | * locks briefly to get the record off the freelist or to allocate the
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| 175 | * buffer, and locks briefly to send the buffer to the netlink layer or
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| 176 | * to place it on a transmit queue. Multiple audit_buffers can be in
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| 177 | * use simultaneously.
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| 178 | struct audit_buffer {
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| 179 | struct list_head list;
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| 180 | struct sk_buff *skb;
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| 181 | struct audit_context *ctx;
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| 182 | gfp_t gfp_mask;
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| 183 | };
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| 184 |
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| 185 | struct audit_reply {
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| 186 | __u32 portid;
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| 187 | struct net *net;
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| 188 | struct sk_buff *skb;
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| 189 | };
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| 190 |
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| 191 | static void audit_set_portid(struct audit_buffer *ab, __u32 portid)
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| 192 | {
|
| 193 | if (ab) {
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| 194 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
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| 195 | nlh->nlmsg_pid = portid;
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| 196 | }
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| 197 | }
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| 198 |
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| 199 | void audit_panic(const char *message)
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| 200 | {
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| 201 | switch (audit_failure) {
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| 202 | case AUDIT_FAIL_SILENT:
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| 203 | break;
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| 204 | case AUDIT_FAIL_PRINTK:
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| 205 | if (printk_ratelimit())
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| 206 | pr_err("%s\n", message);
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| 207 | break;
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| 208 | case AUDIT_FAIL_PANIC:
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| 209 |
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| 210 | if (audit_pid)
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| 211 | panic("audit: %s\n", message);
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| 212 | break;
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| 213 | }
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| 214 | }
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| 215 |
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| 216 | static inline int audit_rate_check(void)
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| 217 | {
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| 218 | static unsigned long last_check = 0;
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| 219 | static int messages = 0;
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| 220 | static DEFINE_SPINLOCK(lock);
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| 221 | unsigned long flags;
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| 222 | unsigned long now;
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| 223 | unsigned long elapsed;
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| 224 | int retval = 0;
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| 225 |
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| 226 | if (!audit_rate_limit) return 1;
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| 227 |
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| 228 | spin_lock_irqsave(&lock, flags);
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| 229 | if (++messages < audit_rate_limit) {
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| 230 | retval = 1;
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| 231 | } else {
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| 232 | now = jiffies;
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| 233 | elapsed = now - last_check;
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| 234 | if (elapsed > HZ) {
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| 235 | last_check = now;
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| 236 | messages = 0;
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| 237 | retval = 1;
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| 238 | }
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| 239 | }
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| 240 | spin_unlock_irqrestore(&lock, flags);
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| 241 |
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| 242 | return retval;
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| 243 | }
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| 244 |
|
| 245 | |
| 246 | * audit_log_lost - conditionally log lost audit message event
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| 247 | * @message: the message stating reason for lost audit message
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| 248 | *
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| 249 | * Emit at least 1 message per second, even if audit_rate_check is
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| 250 | * throttling.
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| 251 | * Always increment the lost messages counter.
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| 252 |
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| 253 | void audit_log_lost(const char *message)
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| 254 | {
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| 255 | static unsigned long last_msg = 0;
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| 256 | static DEFINE_SPINLOCK(lock);
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| 257 | unsigned long flags;
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| 258 | unsigned long now;
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| 259 | int print;
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| 260 |
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| 261 | atomic_inc(&audit_lost);
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| 262 |
|
| 263 | print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit);
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| 264 |
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| 265 | if (!print) {
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| 266 | spin_lock_irqsave(&lock, flags);
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| 267 | now = jiffies;
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| 268 | if (now - last_msg > HZ) {
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| 269 | print = 1;
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| 270 | last_msg = now;
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| 271 | }
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| 272 | spin_unlock_irqrestore(&lock, flags);
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| 273 | }
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| 274 |
|
| 275 | if (print) {
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| 276 | if (printk_ratelimit())
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| 277 | pr_warn("audit_lost=%u audit_rate_limit=%u audit_backlog_limit=%u\n",
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| 278 | atomic_read(&audit_lost),
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| 279 | audit_rate_limit,
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| 280 | audit_backlog_limit);
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| 281 | audit_panic(message);
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| 282 | }
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| 283 | }
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| 284 |
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| 285 | static int audit_log_config_change(char *function_name, u32 new, u32 old,
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| 286 | int allow_changes)
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| 287 | {
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| 288 | struct audit_buffer *ab;
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| 289 | int rc = 0;
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| 290 |
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| 291 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE);
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| 292 | if (unlikely(!ab))
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| 293 | return rc;
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| 294 | audit_log_format(ab, "%s=%u old=%u", function_name, new, old);
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| 295 | audit_log_session_info(ab);
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| 296 | rc = audit_log_task_context(ab);
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| 297 | if (rc)
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| 298 | allow_changes = 0;
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| 299 | audit_log_format(ab, " res=%d", allow_changes);
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| 300 | audit_log_end(ab);
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| 301 | return rc;
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| 302 | }
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| 303 |
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| 304 | static int audit_do_config_change(char *function_name, u32 *to_change, u32 new)
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| 305 | {
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| 306 | int allow_changes, rc = 0;
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| 307 | u32 old = *to_change;
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| 308 |
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| 309 |
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| 310 | if (audit_enabled == AUDIT_LOCKED)
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| 311 | allow_changes = 0;
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| 312 | else
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| 313 | allow_changes = 1;
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| 314 |
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| 315 | if (audit_enabled != AUDIT_OFF) {
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| 316 | rc = audit_log_config_change(function_name, new, old, allow_changes);
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| 317 | if (rc)
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| 318 | allow_changes = 0;
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| 319 | }
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| 320 |
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| 321 |
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| 322 | if (allow_changes == 1)
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| 323 | *to_change = new;
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| 324 |
|
| 325 | else if (rc == 0)
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| 326 | rc = -EPERM;
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| 327 | return rc;
|
| 328 | }
|
| 329 |
|
| 330 | static int audit_set_rate_limit(u32 limit)
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| 331 | {
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| 332 | return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit);
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| 333 | }
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| 334 |
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| 335 | static int audit_set_backlog_limit(u32 limit)
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| 336 | {
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| 337 | return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit);
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| 338 | }
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| 339 |
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| 340 | static int audit_set_backlog_wait_time(u32 timeout)
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| 341 | {
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| 342 | return audit_do_config_change("audit_backlog_wait_time",
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| 343 | &audit_backlog_wait_time_master, timeout);
|
| 344 | }
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| 345 |
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| 346 | static int audit_set_enabled(u32 state)
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| 347 | {
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| 348 | int rc;
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| 349 | if (state > AUDIT_LOCKED)
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| 350 | return -EINVAL;
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| 351 |
|
| 352 | rc = audit_do_config_change("audit_enabled", &audit_enabled, state);
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| 353 | if (!rc)
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| 354 | audit_ever_enabled |= !!state;
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| 355 |
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| 356 | return rc;
|
| 357 | }
|
| 358 |
|
| 359 | static int audit_set_failure(u32 state)
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| 360 | {
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| 361 | if (state != AUDIT_FAIL_SILENT
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| 362 | && state != AUDIT_FAIL_PRINTK
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| 363 | && state != AUDIT_FAIL_PANIC)
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| 364 | return -EINVAL;
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| 365 |
|
| 366 | return audit_do_config_change("audit_failure", &audit_failure, state);
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| 367 | }
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| 368 |
|
| 369 | |
| 370 | * Queue skbs to be sent to auditd when/if it comes back. These skbs should
|
| 371 | * already have been sent via prink/syslog and so if these messages are dropped
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| 372 | * it is not a huge concern since we already passed the audit_log_lost()
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| 373 | * notification and stuff. This is just nice to get audit messages during
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| 374 | * boot before auditd is running or messages generated while auditd is stopped.
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| 375 | * This only holds messages is audit_default is set, aka booting with audit=1
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| 376 | * or building your kernel that way.
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| 377 |
|
| 378 | static void audit_hold_skb(struct sk_buff *skb)
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| 379 | {
|
| 380 | if (audit_default &&
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| 381 | (!audit_backlog_limit ||
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| 382 | skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit))
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| 383 | skb_queue_tail(&audit_skb_hold_queue, skb);
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| 384 | else
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| 385 | kfree_skb(skb);
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| 386 | }
|
| 387 |
|
| 388 | |
| 389 | * For one reason or another this nlh isn't getting delivered to the userspace
|
| 390 | * audit daemon, just send it to printk.
|
| 391 |
|
| 392 | static void audit_printk_skb(struct sk_buff *skb)
|
| 393 | {
|
| 394 | struct nlmsghdr *nlh = nlmsg_hdr(skb);
|
| 395 | char *data = nlmsg_data(nlh);
|
| 396 |
|
| 397 | if (nlh->nlmsg_type != AUDIT_EOE) {
|
| 398 | if (printk_ratelimit())
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| 399 | pr_notice("type=%d %s\n", nlh->nlmsg_type, data);
|
| 400 | else
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| 401 | audit_log_lost("printk limit exceeded");
|
| 402 | }
|
| 403 |
|
| 404 | audit_hold_skb(skb);
|
| 405 | }
|
| 406 |
|
| 407 | static void kauditd_send_skb(struct sk_buff *skb)
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| 408 | {
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| 409 | int err;
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| 410 |
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| 411 | skb_get(skb);
|
| 412 | err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0);
|
| 413 | if (err < 0) {
|
| 414 | BUG_ON(err != -ECONNREFUSED);
|
| 415 | if (audit_pid) {
|
| 416 | pr_err("*NO* daemon at audit_pid=%d\n", audit_pid);
|
| 417 | audit_log_lost("auditd disappeared");
|
| 418 | audit_pid = 0;
|
| 419 | audit_sock = NULL;
|
| 420 | }
|
| 421 |
|
| 422 | audit_hold_skb(skb);
|
| 423 | } else
|
| 424 |
|
| 425 | consume_skb(skb);
|
| 426 | }
|
| 427 |
|
| 428 | |
| 429 | * kauditd_send_multicast_skb - send the skb to multicast userspace listeners
|
| 430 | *
|
| 431 | * This function doesn't consume an skb as might be expected since it has to
|
| 432 | * copy it anyways.
|
| 433 |
|
| 434 | static void kauditd_send_multicast_skb(struct sk_buff *skb, gfp_t gfp_mask)
|
| 435 | {
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| 436 | struct sk_buff *copy;
|
| 437 | struct audit_net *aunet = net_generic(&init_net, audit_net_id);
|
| 438 | struct sock *sock = aunet->nlsk;
|
| 439 |
|
| 440 | if (!netlink_has_listeners(sock, AUDIT_NLGRP_READLOG))
|
| 441 | return;
|
| 442 |
|
| 443 | |
| 444 | * The seemingly wasteful skb_copy() rather than bumping the refcount
|
| 445 | * using skb_get() is necessary because non-standard mods are made to
|
| 446 | * the skb by the original kaudit unicast socket send routine. The
|
| 447 | * existing auditd daemon assumes this breakage. Fixing this would
|
| 448 | * require co-ordinating a change in the established protocol between
|
| 449 | * the kaudit kernel subsystem and the auditd userspace code. There is
|
| 450 | * no reason for new multicast clients to continue with this
|
| 451 | * non-compliance.
|
| 452 |
|
| 453 | copy = skb_copy(skb, gfp_mask);
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| 454 | if (!copy)
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| 455 | return;
|
| 456 |
|
| 457 | nlmsg_multicast(sock, copy, 0, AUDIT_NLGRP_READLOG, gfp_mask);
|
| 458 | }
|
| 459 |
|
| 460 | |
| 461 | * flush_hold_queue - empty the hold queue if auditd appears
|
| 462 | *
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| 463 | * If auditd just started, drain the queue of messages already
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| 464 | * sent to syslog/printk. Remember loss here is ok. We already
|
| 465 | * called audit_log_lost() if it didn't go out normally. so the
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| 466 | * race between the skb_dequeue and the next check for audit_pid
|
| 467 | * doesn't matter.
|
| 468 | *
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| 469 | * If you ever find kauditd to be too slow we can get a perf win
|
| 470 | * by doing our own locking and keeping better track if there
|
| 471 | * are messages in this queue. I don't see the need now, but
|
| 472 | * in 5 years when I want to play with this again I'll see this
|
| 473 | * note and still have no friggin idea what i'm thinking today.
|
| 474 |
|
| 475 | static void flush_hold_queue(void)
|
| 476 | {
|
| 477 | struct sk_buff *skb;
|
| 478 |
|
| 479 | if (!audit_default || !audit_pid)
|
| 480 | return;
|
| 481 |
|
| 482 | skb = skb_dequeue(&audit_skb_hold_queue);
|
| 483 | if (likely(!skb))
|
| 484 | return;
|
| 485 |
|
| 486 | while (skb && audit_pid) {
|
| 487 | kauditd_send_skb(skb);
|
| 488 | skb = skb_dequeue(&audit_skb_hold_queue);
|
| 489 | }
|
| 490 |
|
| 491 | |
| 492 | * if auditd just disappeared but we
|
| 493 | * dequeued an skb we need to drop ref
|
| 494 |
|
| 495 | if (skb)
|
| 496 | consume_skb(skb);
|
| 497 | }
|
| 498 |
|
| 499 | static int kauditd_thread(void *dummy)
|
| 500 | {
|
| 501 | set_freezable();
|
| 502 | while (!kthread_should_stop()) {
|
| 503 | struct sk_buff *skb;
|
| 504 |
|
| 505 | flush_hold_queue();
|
| 506 |
|
| 507 | skb = skb_dequeue(&audit_skb_queue);
|
| 508 |
|
| 509 | if (skb) {
|
| 510 | if (skb_queue_len(&audit_skb_queue) <= audit_backlog_limit)
|
| 511 | wake_up(&audit_backlog_wait);
|
| 512 | if (audit_pid)
|
| 513 | kauditd_send_skb(skb);
|
| 514 | else
|
| 515 | audit_printk_skb(skb);
|
| 516 | continue;
|
| 517 | }
|
| 518 |
|
| 519 | wait_event_freezable(kauditd_wait, skb_queue_len(&audit_skb_queue));
|
| 520 | }
|
| 521 | return 0;
|
| 522 | }
|
| 523 |
|
| 524 | int audit_send_list(void *_dest)
|
| 525 | {
|
| 526 | struct audit_netlink_list *dest = _dest;
|
| 527 | struct sk_buff *skb;
|
| 528 | struct net *net = dest->net;
|
| 529 | struct audit_net *aunet = net_generic(net, audit_net_id);
|
| 530 |
|
| 531 |
|
| 532 | mutex_lock(&audit_cmd_mutex);
|
| 533 | mutex_unlock(&audit_cmd_mutex);
|
| 534 |
|
| 535 | while ((skb = __skb_dequeue(&dest->q)) != NULL)
|
| 536 | netlink_unicast(aunet->nlsk, skb, dest->portid, 0);
|
| 537 |
|
| 538 | put_net(net);
|
| 539 | kfree(dest);
|
| 540 |
|
| 541 | return 0;
|
| 542 | }
|
| 543 |
|
| 544 | struct sk_buff *audit_make_reply(__u32 portid, int seq, int type, int done,
|
| 545 | int multi, const void *payload, int size)
|
| 546 | {
|
| 547 | struct sk_buff *skb;
|
| 548 | struct nlmsghdr *nlh;
|
| 549 | void *data;
|
| 550 | int flags = multi ? NLM_F_MULTI : 0;
|
| 551 | int t = done ? NLMSG_DONE : type;
|
| 552 |
|
| 553 | skb = nlmsg_new(size, GFP_KERNEL);
|
| 554 | if (!skb)
|
| 555 | return NULL;
|
| 556 |
|
| 557 | nlh = nlmsg_put(skb, portid, seq, t, size, flags);
|
| 558 | if (!nlh)
|
| 559 | goto out_kfree_skb;
|
| 560 | data = nlmsg_data(nlh);
|
| 561 | memcpy(data, payload, size);
|
| 562 | return skb;
|
| 563 |
|
| 564 | out_kfree_skb:
|
| 565 | kfree_skb(skb);
|
| 566 | return NULL;
|
| 567 | }
|
| 568 |
|
| 569 | static int audit_send_reply_thread(void *arg)
|
| 570 | {
|
| 571 | struct audit_reply *reply = (struct audit_reply *)arg;
|
| 572 | struct net *net = reply->net;
|
| 573 | struct audit_net *aunet = net_generic(net, audit_net_id);
|
| 574 |
|
| 575 | mutex_lock(&audit_cmd_mutex);
|
| 576 | mutex_unlock(&audit_cmd_mutex);
|
| 577 |
|
| 578 | |
| 579 | because our timeout is set to infinite.
|
| 580 | netlink_unicast(aunet->nlsk , reply->skb, reply->portid, 0);
|
| 581 | put_net(net);
|
| 582 | kfree(reply);
|
| 583 | return 0;
|
| 584 | }
|
| 585 | |
| 586 | * audit_send_reply - send an audit reply message via netlink
|
| 587 | * @request_skb: skb of request we are replying to (used to target the reply)
|
| 588 | * @seq: sequence number
|
| 589 | * @type: audit message type
|
| 590 | * @done: done (last) flag
|
| 591 | * @multi: multi-part message flag
|
| 592 | * @payload: payload data
|
| 593 | * @size: payload size
|
| 594 | *
|
| 595 | * Allocates an skb, builds the netlink message, and sends it to the port id.
|
| 596 | * No failure notifications.
|
| 597 |
|
| 598 | static void audit_send_reply(struct sk_buff *request_skb, int seq, int type, int done,
|
| 599 | int multi, const void *payload, int size)
|
| 600 | {
|
| 601 | u32 portid = NETLINK_CB(request_skb).portid;
|
| 602 | struct net *net = sock_net(NETLINK_CB(request_skb).sk);
|
| 603 | struct sk_buff *skb;
|
| 604 | struct task_struct *tsk;
|
| 605 | struct audit_reply *reply = kmalloc(sizeof(struct audit_reply),
|
| 606 | GFP_KERNEL);
|
| 607 |
|
| 608 | if (!reply)
|
| 609 | return;
|
| 610 |
|
| 611 | skb = audit_make_reply(portid, seq, type, done, multi, payload, size);
|
| 612 | if (!skb)
|
| 613 | goto out;
|
| 614 |
|
| 615 | reply->net = get_net(net);
|
| 616 | reply->portid = portid;
|
| 617 | reply->skb = skb;
|
| 618 |
|
| 619 | tsk = kthread_run(audit_send_reply_thread, reply, "audit_send_reply");
|
| 620 | if (!IS_ERR(tsk))
|
| 621 | return;
|
| 622 | kfree_skb(skb);
|
| 623 | out:
|
| 624 | kfree(reply);
|
| 625 | }
|
| 626 |
|
| 627 | |
| 628 | * Check for appropriate CAP_AUDIT_ capabilities on incoming audit
|
| 629 | * control messages.
|
| 630 |
|
| 631 | static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
|
| 632 | {
|
| 633 | int err = 0;
|
| 634 |
|
| 635 |
|
| 636 | |
| 637 | * We return ECONNREFUSED because it tricks userspace into thinking
|
| 638 | * that audit was not configured into the kernel. Lots of users
|
| 639 | * configure their PAM stack (because that's what the distro does)
|
| 640 | * to reject login if unable to send messages to audit. If we return
|
| 641 | * ECONNREFUSED the PAM stack thinks the kernel does not have audit
|
| 642 | * configured in and will let login proceed. If we return EPERM
|
| 643 | * userspace will reject all logins. This should be removed when we
|
| 644 | * support non init namespaces!!
|
| 645 |
|
| 646 | if (current_user_ns() != &init_user_ns)
|
| 647 | return -ECONNREFUSED;
|
| 648 |
|
| 649 | switch (msg_type) {
|
| 650 | case AUDIT_LIST:
|
| 651 | case AUDIT_ADD:
|
| 652 | case AUDIT_DEL:
|
| 653 | return -EOPNOTSUPP;
|
| 654 | case AUDIT_GET:
|
| 655 | case AUDIT_SET:
|
| 656 | case AUDIT_GET_FEATURE:
|
| 657 | case AUDIT_SET_FEATURE:
|
| 658 | case AUDIT_LIST_RULES:
|
| 659 | case AUDIT_ADD_RULE:
|
| 660 | case AUDIT_DEL_RULE:
|
| 661 | case AUDIT_SIGNAL_INFO:
|
| 662 | case AUDIT_TTY_GET:
|
| 663 | case AUDIT_TTY_SET:
|
| 664 | case AUDIT_TRIM:
|
| 665 | case AUDIT_MAKE_EQUIV:
|
| 666 | |
| 667 | * for now.
|
| 668 | if (task_active_pid_ns(current) != &init_pid_ns)
|
| 669 | return -EPERM;
|
| 670 |
|
| 671 | if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
|
| 672 | err = -EPERM;
|
| 673 | break;
|
| 674 | case AUDIT_USER:
|
| 675 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 676 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 677 | if (!netlink_capable(skb, CAP_AUDIT_WRITE))
|
| 678 | err = -EPERM;
|
| 679 | break;
|
| 680 | default:
|
| 681 | err = -EINVAL;
|
| 682 | }
|
| 683 |
|
| 684 | return err;
|
| 685 | }
|
| 686 |
|
| 687 | static int audit_log_common_recv_msg(struct audit_buffer **ab, u16 msg_type)
|
| 688 | {
|
| 689 | int rc = 0;
|
| 690 | uid_t uid = from_kuid(&init_user_ns, current_uid());
|
| 691 | pid_t pid = task_tgid_nr(current);
|
| 692 |
|
| 693 | if (!audit_enabled && msg_type != AUDIT_USER_AVC) {
|
| 694 | *ab = NULL;
|
| 695 | return rc;
|
| 696 | }
|
| 697 |
|
| 698 | *ab = audit_log_start(NULL, GFP_KERNEL, msg_type);
|
| 699 | if (unlikely(!*ab))
|
| 700 | return rc;
|
| 701 | audit_log_format(*ab, "pid=%d uid=%u", pid, uid);
|
| 702 | audit_log_session_info(*ab);
|
| 703 | audit_log_task_context(*ab);
|
| 704 |
|
| 705 | return rc;
|
| 706 | }
|
| 707 |
|
| 708 | int is_audit_feature_set(int i)
|
| 709 | {
|
| 710 | return af.features & AUDIT_FEATURE_TO_MASK(i);
|
| 711 | }
|
| 712 |
|
| 713 |
|
| 714 | static int audit_get_feature(struct sk_buff *skb)
|
| 715 | {
|
| 716 | u32 seq;
|
| 717 |
|
| 718 | seq = nlmsg_hdr(skb)->nlmsg_seq;
|
| 719 |
|
| 720 | audit_send_reply(skb, seq, AUDIT_GET_FEATURE, 0, 0, &af, sizeof(af));
|
| 721 |
|
| 722 | return 0;
|
| 723 | }
|
| 724 |
|
| 725 | static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature,
|
| 726 | u32 old_lock, u32 new_lock, int res)
|
| 727 | {
|
| 728 | struct audit_buffer *ab;
|
| 729 |
|
| 730 | if (audit_enabled == AUDIT_OFF)
|
| 731 | return;
|
| 732 |
|
| 733 | ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
|
| 734 | audit_log_task_info(ab, current);
|
| 735 | audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
|
| 736 | audit_feature_names[which], !!old_feature, !!new_feature,
|
| 737 | !!old_lock, !!new_lock, res);
|
| 738 | audit_log_end(ab);
|
| 739 | }
|
| 740 |
|
| 741 | static int audit_set_feature(struct sk_buff *skb)
|
| 742 | {
|
| 743 | struct audit_features *uaf;
|
| 744 | int i;
|
| 745 |
|
| 746 | BUILD_BUG_ON(AUDIT_LAST_FEATURE + 1 > ARRAY_SIZE(audit_feature_names));
|
| 747 | uaf = nlmsg_data(nlmsg_hdr(skb));
|
| 748 |
|
| 749 |
|
| 750 |
|
| 751 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
|
| 752 | u32 feature = AUDIT_FEATURE_TO_MASK(i);
|
| 753 | u32 old_feature, new_feature, old_lock, new_lock;
|
| 754 |
|
| 755 |
|
| 756 | if (!(feature & uaf->mask))
|
| 757 | continue;
|
| 758 |
|
| 759 | old_feature = af.features & feature;
|
| 760 | new_feature = uaf->features & feature;
|
| 761 | new_lock = (uaf->lock | af.lock) & feature;
|
| 762 | old_lock = af.lock & feature;
|
| 763 |
|
| 764 |
|
| 765 | if (old_lock && (new_feature != old_feature)) {
|
| 766 | audit_log_feature_change(i, old_feature, new_feature,
|
| 767 | old_lock, new_lock, 0);
|
| 768 | return -EPERM;
|
| 769 | }
|
| 770 | }
|
| 771 |
|
| 772 | for (i = 0; i <= AUDIT_LAST_FEATURE; i++) {
|
| 773 | u32 feature = AUDIT_FEATURE_TO_MASK(i);
|
| 774 | u32 old_feature, new_feature, old_lock, new_lock;
|
| 775 |
|
| 776 |
|
| 777 | if (!(feature & uaf->mask))
|
| 778 | continue;
|
| 779 |
|
| 780 | old_feature = af.features & feature;
|
| 781 | new_feature = uaf->features & feature;
|
| 782 | old_lock = af.lock & feature;
|
| 783 | new_lock = (uaf->lock | af.lock) & feature;
|
| 784 |
|
| 785 | if (new_feature != old_feature)
|
| 786 | audit_log_feature_change(i, old_feature, new_feature,
|
| 787 | old_lock, new_lock, 1);
|
| 788 |
|
| 789 | if (new_feature)
|
| 790 | af.features |= feature;
|
| 791 | else
|
| 792 | af.features &= ~feature;
|
| 793 | af.lock |= new_lock;
|
| 794 | }
|
| 795 |
|
| 796 | return 0;
|
| 797 | }
|
| 798 |
|
| 799 | static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
|
| 800 | {
|
| 801 | u32 seq;
|
| 802 | void *data;
|
| 803 | int err;
|
| 804 | struct audit_buffer *ab;
|
| 805 | u16 msg_type = nlh->nlmsg_type;
|
| 806 | struct audit_sig_info *sig_data;
|
| 807 | char *ctx = NULL;
|
| 808 | u32 len;
|
| 809 |
|
| 810 | err = audit_netlink_ok(skb, msg_type);
|
| 811 | if (err)
|
| 812 | return err;
|
| 813 |
|
| 814 | |
| 815 | * start kauditd to talk to it
|
| 816 | if (!kauditd_task) {
|
| 817 | kauditd_task = kthread_run(kauditd_thread, NULL, "kauditd");
|
| 818 | if (IS_ERR(kauditd_task)) {
|
| 819 | err = PTR_ERR(kauditd_task);
|
| 820 | kauditd_task = NULL;
|
| 821 | return err;
|
| 822 | }
|
| 823 | }
|
| 824 | seq = nlh->nlmsg_seq;
|
| 825 | data = nlmsg_data(nlh);
|
| 826 |
|
| 827 | switch (msg_type) {
|
| 828 | case AUDIT_GET: {
|
| 829 | struct audit_status s;
|
| 830 | memset(&s, 0, sizeof(s));
|
| 831 | s.enabled = audit_enabled;
|
| 832 | s.failure = audit_failure;
|
| 833 | s.pid = audit_pid;
|
| 834 | s.rate_limit = audit_rate_limit;
|
| 835 | s.backlog_limit = audit_backlog_limit;
|
| 836 | s.lost = atomic_read(&audit_lost);
|
| 837 | s.backlog = skb_queue_len(&audit_skb_queue);
|
| 838 | s.feature_bitmap = AUDIT_FEATURE_BITMAP_ALL;
|
| 839 | s.backlog_wait_time = audit_backlog_wait_time_master;
|
| 840 | audit_send_reply(skb, seq, AUDIT_GET, 0, 0, &s, sizeof(s));
|
| 841 | break;
|
| 842 | }
|
| 843 | case AUDIT_SET: {
|
| 844 | struct audit_status s;
|
| 845 | memset(&s, 0, sizeof(s));
|
| 846 |
|
| 847 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
|
| 848 | if (s.mask & AUDIT_STATUS_ENABLED) {
|
| 849 | err = audit_set_enabled(s.enabled);
|
| 850 | if (err < 0)
|
| 851 | return err;
|
| 852 | }
|
| 853 | if (s.mask & AUDIT_STATUS_FAILURE) {
|
| 854 | err = audit_set_failure(s.failure);
|
| 855 | if (err < 0)
|
| 856 | return err;
|
| 857 | }
|
| 858 | if (s.mask & AUDIT_STATUS_PID) {
|
| 859 | int new_pid = s.pid;
|
| 860 |
|
| 861 | if ((!new_pid) && (task_tgid_vnr(current) != audit_pid))
|
| 862 | return -EACCES;
|
| 863 | if (audit_enabled != AUDIT_OFF)
|
| 864 | audit_log_config_change("audit_pid", new_pid, audit_pid, 1);
|
| 865 | audit_pid = new_pid;
|
| 866 | audit_nlk_portid = NETLINK_CB(skb).portid;
|
| 867 | audit_sock = skb->sk;
|
| 868 | }
|
| 869 | if (s.mask & AUDIT_STATUS_RATE_LIMIT) {
|
| 870 | err = audit_set_rate_limit(s.rate_limit);
|
| 871 | if (err < 0)
|
| 872 | return err;
|
| 873 | }
|
| 874 | if (s.mask & AUDIT_STATUS_BACKLOG_LIMIT) {
|
| 875 | err = audit_set_backlog_limit(s.backlog_limit);
|
| 876 | if (err < 0)
|
| 877 | return err;
|
| 878 | }
|
| 879 | if (s.mask & AUDIT_STATUS_BACKLOG_WAIT_TIME) {
|
| 880 | if (sizeof(s) > (size_t)nlh->nlmsg_len)
|
| 881 | return -EINVAL;
|
| 882 | if (s.backlog_wait_time > 10*AUDIT_BACKLOG_WAIT_TIME)
|
| 883 | return -EINVAL;
|
| 884 | err = audit_set_backlog_wait_time(s.backlog_wait_time);
|
| 885 | if (err < 0)
|
| 886 | return err;
|
| 887 | }
|
| 888 | break;
|
| 889 | }
|
| 890 | case AUDIT_GET_FEATURE:
|
| 891 | err = audit_get_feature(skb);
|
| 892 | if (err)
|
| 893 | return err;
|
| 894 | break;
|
| 895 | case AUDIT_SET_FEATURE:
|
| 896 | err = audit_set_feature(skb);
|
| 897 | if (err)
|
| 898 | return err;
|
| 899 | break;
|
| 900 | case AUDIT_USER:
|
| 901 | case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
|
| 902 | case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
|
| 903 | if (!audit_enabled && msg_type != AUDIT_USER_AVC)
|
| 904 | return 0;
|
| 905 |
|
| 906 | err = audit_filter_user(msg_type);
|
| 907 | if (err == 1) {
|
| 908 | err = 0;
|
| 909 | if (msg_type == AUDIT_USER_TTY) {
|
| 910 | err = tty_audit_push_current();
|
| 911 | if (err)
|
| 912 | break;
|
| 913 | }
|
| 914 | mutex_unlock(&audit_cmd_mutex);
|
| 915 | audit_log_common_recv_msg(&ab, msg_type);
|
| 916 | if (msg_type != AUDIT_USER_TTY)
|
| 917 | audit_log_format(ab, " msg='%.*s'",
|
| 918 | AUDIT_MESSAGE_TEXT_MAX,
|
| 919 | (char *)data);
|
| 920 | else {
|
| 921 | int size;
|
| 922 |
|
| 923 | audit_log_format(ab, " data=");
|
| 924 | size = nlmsg_len(nlh);
|
| 925 | if (size > 0 &&
|
| 926 | ((unsigned char *)data)[size - 1] == '\0')
|
| 927 | size--;
|
| 928 | audit_log_n_untrustedstring(ab, data, size);
|
| 929 | }
|
| 930 | audit_set_portid(ab, NETLINK_CB(skb).portid);
|
| 931 | audit_log_end(ab);
|
| 932 | mutex_lock(&audit_cmd_mutex);
|
| 933 | }
|
| 934 | break;
|
| 935 | case AUDIT_ADD_RULE:
|
| 936 | case AUDIT_DEL_RULE:
|
| 937 | if (nlmsg_len(nlh) < sizeof(struct audit_rule_data))
|
| 938 | return -EINVAL;
|
| 939 | if (audit_enabled == AUDIT_LOCKED) {
|
| 940 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
| 941 | audit_log_format(ab, " audit_enabled=%d res=0", audit_enabled);
|
| 942 | audit_log_end(ab);
|
| 943 | return -EPERM;
|
| 944 | }
|
| 945 | err = audit_rule_change(msg_type, NETLINK_CB(skb).portid,
|
| 946 | seq, data, nlmsg_len(nlh));
|
| 947 | break;
|
| 948 | case AUDIT_LIST_RULES:
|
| 949 | err = audit_list_rules_send(skb, seq);
|
| 950 | break;
|
| 951 | case AUDIT_TRIM:
|
| 952 | audit_trim_trees();
|
| 953 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
| 954 | audit_log_format(ab, " op=trim res=1");
|
| 955 | audit_log_end(ab);
|
| 956 | break;
|
| 957 | case AUDIT_MAKE_EQUIV: {
|
| 958 | void *bufp = data;
|
| 959 | u32 sizes[2];
|
| 960 | size_t msglen = nlmsg_len(nlh);
|
| 961 | char *old, *new;
|
| 962 |
|
| 963 | err = -EINVAL;
|
| 964 | if (msglen < 2 * sizeof(u32))
|
| 965 | break;
|
| 966 | memcpy(sizes, bufp, 2 * sizeof(u32));
|
| 967 | bufp += 2 * sizeof(u32);
|
| 968 | msglen -= 2 * sizeof(u32);
|
| 969 | old = audit_unpack_string(&bufp, &msglen, sizes[0]);
|
| 970 | if (IS_ERR(old)) {
|
| 971 | err = PTR_ERR(old);
|
| 972 | break;
|
| 973 | }
|
| 974 | new = audit_unpack_string(&bufp, &msglen, sizes[1]);
|
| 975 | if (IS_ERR(new)) {
|
| 976 | err = PTR_ERR(new);
|
| 977 | kfree(old);
|
| 978 | break;
|
| 979 | }
|
| 980 |
|
| 981 | err = audit_tag_tree(old, new);
|
| 982 |
|
| 983 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
| 984 |
|
| 985 | audit_log_format(ab, " op=make_equiv old=");
|
| 986 | audit_log_untrustedstring(ab, old);
|
| 987 | audit_log_format(ab, " new=");
|
| 988 | audit_log_untrustedstring(ab, new);
|
| 989 | audit_log_format(ab, " res=%d", !err);
|
| 990 | audit_log_end(ab);
|
| 991 | kfree(old);
|
| 992 | kfree(new);
|
| 993 | break;
|
| 994 | }
|
| 995 | case AUDIT_SIGNAL_INFO:
|
| 996 | len = 0;
|
| 997 | if (audit_sig_sid) {
|
| 998 | err = security_secid_to_secctx(audit_sig_sid, &ctx, &len);
|
| 999 | if (err)
|
| 1000 | return err;
|
| 1001 | }
|
| 1002 | sig_data = kmalloc(sizeof(*sig_data) + len, GFP_KERNEL);
|
| 1003 | if (!sig_data) {
|
| 1004 | if (audit_sig_sid)
|
| 1005 | security_release_secctx(ctx, len);
|
| 1006 | return -ENOMEM;
|
| 1007 | }
|
| 1008 | sig_data->uid = from_kuid(&init_user_ns, audit_sig_uid);
|
| 1009 | sig_data->pid = audit_sig_pid;
|
| 1010 | if (audit_sig_sid) {
|
| 1011 | memcpy(sig_data->ctx, ctx, len);
|
| 1012 | security_release_secctx(ctx, len);
|
| 1013 | }
|
| 1014 | audit_send_reply(skb, seq, AUDIT_SIGNAL_INFO, 0, 0,
|
| 1015 | sig_data, sizeof(*sig_data) + len);
|
| 1016 | kfree(sig_data);
|
| 1017 | break;
|
| 1018 | case AUDIT_TTY_GET: {
|
| 1019 | struct audit_tty_status s;
|
| 1020 | struct task_struct *tsk = current;
|
| 1021 |
|
| 1022 | spin_lock(&tsk->sighand->siglock);
|
| 1023 | s.enabled = tsk->signal->audit_tty;
|
| 1024 | s.log_passwd = tsk->signal->audit_tty_log_passwd;
|
| 1025 | spin_unlock(&tsk->sighand->siglock);
|
| 1026 |
|
| 1027 | audit_send_reply(skb, seq, AUDIT_TTY_GET, 0, 0, &s, sizeof(s));
|
| 1028 | break;
|
| 1029 | }
|
| 1030 | case AUDIT_TTY_SET: {
|
| 1031 | struct audit_tty_status s, old;
|
| 1032 | struct task_struct *tsk = current;
|
| 1033 | struct audit_buffer *ab;
|
| 1034 |
|
| 1035 | memset(&s, 0, sizeof(s));
|
| 1036 |
|
| 1037 | memcpy(&s, data, min_t(size_t, sizeof(s), nlmsg_len(nlh)));
|
| 1038 |
|
| 1039 | if ((s.enabled != 0 && s.enabled != 1) ||
|
| 1040 | (s.log_passwd != 0 && s.log_passwd != 1))
|
| 1041 | err = -EINVAL;
|
| 1042 |
|
| 1043 | spin_lock(&tsk->sighand->siglock);
|
| 1044 | old.enabled = tsk->signal->audit_tty;
|
| 1045 | old.log_passwd = tsk->signal->audit_tty_log_passwd;
|
| 1046 | if (!err) {
|
| 1047 | tsk->signal->audit_tty = s.enabled;
|
| 1048 | tsk->signal->audit_tty_log_passwd = s.log_passwd;
|
| 1049 | }
|
| 1050 | spin_unlock(&tsk->sighand->siglock);
|
| 1051 |
|
| 1052 | audit_log_common_recv_msg(&ab, AUDIT_CONFIG_CHANGE);
|
| 1053 | audit_log_format(ab, " op=tty_set old-enabled=%d new-enabled=%d"
|
| 1054 | " old-log_passwd=%d new-log_passwd=%d res=%d",
|
| 1055 | old.enabled, s.enabled, old.log_passwd,
|
| 1056 | s.log_passwd, !err);
|
| 1057 | audit_log_end(ab);
|
| 1058 | break;
|
| 1059 | }
|
| 1060 | default:
|
| 1061 | err = -EINVAL;
|
| 1062 | break;
|
| 1063 | }
|
| 1064 |
|
| 1065 | return err < 0 ? err : 0;
|
| 1066 | }
|
| 1067 |
|
| 1068 | |
| 1069 | * Get message from skb. Each message is processed by audit_receive_msg.
|
| 1070 | * Malformed skbs with wrong length are discarded silently.
|
| 1071 |
|
| 1072 | static void audit_receive_skb(struct sk_buff *skb)
|
| 1073 | {
|
| 1074 | struct nlmsghdr *nlh;
|
| 1075 | |
| 1076 | * len MUST be signed for nlmsg_next to be able to dec it below 0
|
| 1077 | * if the nlmsg_len was not aligned
|
| 1078 |
|
| 1079 | int len;
|
| 1080 | int err;
|
| 1081 |
|
| 1082 | nlh = nlmsg_hdr(skb);
|
| 1083 | len = skb->len;
|
| 1084 |
|
| 1085 | while (nlmsg_ok(nlh, len)) {
|
| 1086 | err = audit_receive_msg(skb, nlh);
|
| 1087 |
|
| 1088 | if (err || (nlh->nlmsg_flags & NLM_F_ACK))
|
| 1089 | netlink_ack(skb, nlh, err);
|
| 1090 |
|
| 1091 | nlh = nlmsg_next(nlh, &len);
|
| 1092 | }
|
| 1093 | }
|
| 1094 |
|
| 1095 |
|
| 1096 | static void audit_receive(struct sk_buff *skb)
|
| 1097 | {
|
| 1098 | mutex_lock(&audit_cmd_mutex);
|
| 1099 | audit_receive_skb(skb);
|
| 1100 | mutex_unlock(&audit_cmd_mutex);
|
| 1101 | }
|
| 1102 |
|
| 1103 |
|
| 1104 | static int audit_bind(struct net *net, int group)
|
| 1105 | {
|
| 1106 | if (!capable(CAP_AUDIT_READ))
|
| 1107 | return -EPERM;
|
| 1108 |
|
| 1109 | return 0;
|
| 1110 | }
|
| 1111 |
|
| 1112 | static int __net_init audit_net_init(struct net *net)
|
| 1113 | {
|
| 1114 | struct netlink_kernel_cfg cfg = {
|
| 1115 | .input = audit_receive,
|
| 1116 | .bind = audit_bind,
|
| 1117 | .flags = NL_CFG_F_NONROOT_RECV,
|
| 1118 | .groups = AUDIT_NLGRP_MAX,
|
| 1119 | };
|
| 1120 |
|
| 1121 | struct audit_net *aunet = net_generic(net, audit_net_id);
|
| 1122 |
|
| 1123 | aunet->nlsk = netlink_kernel_create(net, NETLINK_AUDIT, &cfg);
|
| 1124 | if (aunet->nlsk == NULL) {
|
| 1125 | audit_panic("cannot initialize netlink socket in namespace");
|
| 1126 | return -ENOMEM;
|
| 1127 | }
|
| 1128 | aunet->nlsk->sk_sndtimeo = MAX_SCHEDULE_TIMEOUT;
|
| 1129 | return 0;
|
| 1130 | }
|
| 1131 |
|
| 1132 | static void __net_exit audit_net_exit(struct net *net)
|
| 1133 | {
|
| 1134 | struct audit_net *aunet = net_generic(net, audit_net_id);
|
| 1135 | struct sock *sock = aunet->nlsk;
|
| 1136 | if (sock == audit_sock) {
|
| 1137 | audit_pid = 0;
|
| 1138 | audit_sock = NULL;
|
| 1139 | }
|
| 1140 |
|
| 1141 | RCU_INIT_POINTER(aunet->nlsk, NULL);
|
| 1142 | synchronize_net();
|
| 1143 | netlink_kernel_release(sock);
|
| 1144 | }
|
| 1145 |
|
| 1146 | static struct pernet_operations audit_net_ops __net_initdata = {
|
| 1147 | .init = audit_net_init,
|
| 1148 | .exit = audit_net_exit,
|
| 1149 | .id = &audit_net_id,
|
| 1150 | .size = sizeof(struct audit_net),
|
| 1151 | };
|
| 1152 |
|
| 1153 |
|
| 1154 | static int __init audit_init(void)
|
| 1155 | {
|
| 1156 | int i;
|
| 1157 |
|
| 1158 | if (audit_initialized == AUDIT_DISABLED)
|
| 1159 | return 0;
|
| 1160 |
|
| 1161 | pr_info("initializing netlink subsys (%s)\n",
|
| 1162 | audit_default ? "enabled" : "disabled");
|
| 1163 | register_pernet_subsys(&audit_net_ops);
|
| 1164 |
|
| 1165 | skb_queue_head_init(&audit_skb_queue);
|
| 1166 | skb_queue_head_init(&audit_skb_hold_queue);
|
| 1167 | audit_initialized = AUDIT_INITIALIZED;
|
| 1168 | audit_enabled = audit_default;
|
| 1169 | audit_ever_enabled |= !!audit_default;
|
| 1170 |
|
| 1171 | audit_log(NULL, GFP_KERNEL, AUDIT_KERNEL, "initialized");
|
| 1172 |
|
| 1173 | for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
|
| 1174 | INIT_LIST_HEAD(&audit_inode_hash[i]);
|
| 1175 |
|
| 1176 | return 0;
|
| 1177 | }
|
| 1178 | __initcall(audit_init);
|
| 1179 |
|
| 1180 |
|
| 1181 | static int __init audit_enable(char *str)
|
| 1182 | {
|
| 1183 | audit_default = !!simple_strtol(str, NULL, 0);
|
| 1184 | if (!audit_default)
|
| 1185 | audit_initialized = AUDIT_DISABLED;
|
| 1186 |
|
| 1187 | pr_info("%s\n", audit_default ?
|
| 1188 | "enabled (after initialization)" : "disabled (until reboot)");
|
| 1189 |
|
| 1190 | return 1;
|
| 1191 | }
|
| 1192 | __setup("audit=", audit_enable);
|
| 1193 |
|
| 1194 | |
| 1195 | * audit_backlog_limit=<n>
|
| 1196 | static int __init audit_backlog_limit_set(char *str)
|
| 1197 | {
|
| 1198 | u32 audit_backlog_limit_arg;
|
| 1199 |
|
| 1200 | pr_info("audit_backlog_limit: ");
|
| 1201 | if (kstrtouint(str, 0, &audit_backlog_limit_arg)) {
|
| 1202 | pr_cont("using default of %u, unable to parse %s\n",
|
| 1203 | audit_backlog_limit, str);
|
| 1204 | return 1;
|
| 1205 | }
|
| 1206 |
|
| 1207 | audit_backlog_limit = audit_backlog_limit_arg;
|
| 1208 | pr_cont("%d\n", audit_backlog_limit);
|
| 1209 |
|
| 1210 | return 1;
|
| 1211 | }
|
| 1212 | __setup("audit_backlog_limit=", audit_backlog_limit_set);
|
| 1213 |
|
| 1214 | static void audit_buffer_free(struct audit_buffer *ab)
|
| 1215 | {
|
| 1216 | unsigned long flags;
|
| 1217 |
|
| 1218 | if (!ab)
|
| 1219 | return;
|
| 1220 |
|
| 1221 | if (ab->skb)
|
| 1222 | kfree_skb(ab->skb);
|
| 1223 |
|
| 1224 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 1225 | if (audit_freelist_count > AUDIT_MAXFREE)
|
| 1226 | kfree(ab);
|
| 1227 | else {
|
| 1228 | audit_freelist_count++;
|
| 1229 | list_add(&ab->list, &audit_freelist);
|
| 1230 | }
|
| 1231 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 1232 | }
|
| 1233 |
|
| 1234 | static struct audit_buffer * audit_buffer_alloc(struct audit_context *ctx,
|
| 1235 | gfp_t gfp_mask, int type)
|
| 1236 | {
|
| 1237 | unsigned long flags;
|
| 1238 | struct audit_buffer *ab = NULL;
|
| 1239 | struct nlmsghdr *nlh;
|
| 1240 |
|
| 1241 | spin_lock_irqsave(&audit_freelist_lock, flags);
|
| 1242 | if (!list_empty(&audit_freelist)) {
|
| 1243 | ab = list_entry(audit_freelist.next,
|
| 1244 | struct audit_buffer, list);
|
| 1245 | list_del(&ab->list);
|
| 1246 | --audit_freelist_count;
|
| 1247 | }
|
| 1248 | spin_unlock_irqrestore(&audit_freelist_lock, flags);
|
| 1249 |
|
| 1250 | if (!ab) {
|
| 1251 | ab = kmalloc(sizeof(*ab), gfp_mask);
|
| 1252 | if (!ab)
|
| 1253 | goto err;
|
| 1254 | }
|
| 1255 |
|
| 1256 | ab->ctx = ctx;
|
| 1257 | ab->gfp_mask = gfp_mask;
|
| 1258 |
|
| 1259 | ab->skb = nlmsg_new(AUDIT_BUFSIZ, gfp_mask);
|
| 1260 | if (!ab->skb)
|
| 1261 | goto err;
|
| 1262 |
|
| 1263 | nlh = nlmsg_put(ab->skb, 0, 0, type, 0, 0);
|
| 1264 | if (!nlh)
|
| 1265 | goto out_kfree_skb;
|
| 1266 |
|
| 1267 | return ab;
|
| 1268 |
|
| 1269 | out_kfree_skb:
|
| 1270 | kfree_skb(ab->skb);
|
| 1271 | ab->skb = NULL;
|
| 1272 | err:
|
| 1273 | audit_buffer_free(ab);
|
| 1274 | return NULL;
|
| 1275 | }
|
| 1276 |
|
| 1277 | |
| 1278 | * audit_serial - compute a serial number for the audit record
|
| 1279 | *
|
| 1280 | * Compute a serial number for the audit record. Audit records are
|
| 1281 | * written to user-space as soon as they are generated, so a complete
|
| 1282 | * audit record may be written in several pieces. The timestamp of the
|
| 1283 | * record and this serial number are used by the user-space tools to
|
| 1284 | * determine which pieces belong to the same audit record. The
|
| 1285 | * (timestamp,serial) tuple is unique for each syscall and is live from
|
| 1286 | * syscall entry to syscall exit.
|
| 1287 | *
|
| 1288 | * NOTE: Another possibility is to store the formatted records off the
|
| 1289 | * audit context (for those records that have a context), and emit them
|
| 1290 | * all at syscall exit. However, this could delay the reporting of
|
| 1291 | * significant errors until syscall exit (or never, if the system
|
| 1292 | * halts).
|
| 1293 |
|
| 1294 | unsigned int audit_serial(void)
|
| 1295 | {
|
| 1296 | static atomic_t serial = ATOMIC_INIT(0);
|
| 1297 |
|
| 1298 | return atomic_add_return(1, &serial);
|
| 1299 | }
|
| 1300 |
|
| 1301 | static inline void audit_get_stamp(struct audit_context *ctx,
|
| 1302 | struct timespec *t, unsigned int *serial)
|
| 1303 | {
|
| 1304 | if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
|
| 1305 | *t = CURRENT_TIME;
|
| 1306 | *serial = audit_serial();
|
| 1307 | }
|
| 1308 | }
|
| 1309 |
|
| 1310 | |
| 1311 | * Wait for auditd to drain the queue a little
|
| 1312 |
|
| 1313 | static long wait_for_auditd(long sleep_time)
|
| 1314 | {
|
| 1315 | DECLARE_WAITQUEUE(wait, current);
|
| 1316 | set_current_state(TASK_UNINTERRUPTIBLE);
|
| 1317 | add_wait_queue_exclusive(&audit_backlog_wait, &wait);
|
| 1318 |
|
| 1319 | if (audit_backlog_limit &&
|
| 1320 | skb_queue_len(&audit_skb_queue) > audit_backlog_limit)
|
| 1321 | sleep_time = schedule_timeout(sleep_time);
|
| 1322 |
|
| 1323 | __set_current_state(TASK_RUNNING);
|
| 1324 | remove_wait_queue(&audit_backlog_wait, &wait);
|
| 1325 |
|
| 1326 | return sleep_time;
|
| 1327 | }
|
| 1328 |
|
| 1329 | |
| 1330 | * audit_log_start - obtain an audit buffer
|
| 1331 | * @ctx: audit_context (may be NULL)
|
| 1332 | * @gfp_mask: type of allocation
|
| 1333 | * @type: audit message type
|
| 1334 | *
|
| 1335 | * Returns audit_buffer pointer on success or NULL on error.
|
| 1336 | *
|
| 1337 | * Obtain an audit buffer. This routine does locking to obtain the
|
| 1338 | * audit buffer, but then no locking is required for calls to
|
| 1339 | * audit_log_*format. If the task (ctx) is a task that is currently in a
|
| 1340 | * syscall, then the syscall is marked as auditable and an audit record
|
| 1341 | * will be written at syscall exit. If there is no associated task, then
|
| 1342 | * task context (ctx) should be NULL.
|
| 1343 |
|
| 1344 | struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
|
| 1345 | int type)
|
| 1346 | {
|
| 1347 | struct audit_buffer *ab = NULL;
|
| 1348 | struct timespec t;
|
| 1349 | unsigned int uninitialized_var(serial);
|
| 1350 | int reserve = 5; |
| 1351 | entries over the normal backlog limit
|
| 1352 | unsigned long timeout_start = jiffies;
|
| 1353 |
|
| 1354 | if (audit_initialized != AUDIT_INITIALIZED)
|
| 1355 | return NULL;
|
| 1356 |
|
| 1357 | if (unlikely(audit_filter_type(type)))
|
| 1358 | return NULL;
|
| 1359 |
|
| 1360 | if (gfp_mask & __GFP_WAIT) {
|
| 1361 | if (audit_pid && audit_pid == current->pid)
|
| 1362 | gfp_mask &= ~__GFP_WAIT;
|
| 1363 | else
|
| 1364 | reserve = 0;
|
| 1365 | }
|
| 1366 |
|
| 1367 | while (audit_backlog_limit
|
| 1368 | && skb_queue_len(&audit_skb_queue) > audit_backlog_limit + reserve) {
|
| 1369 | if (gfp_mask & __GFP_WAIT && audit_backlog_wait_time) {
|
| 1370 | long sleep_time;
|
| 1371 |
|
| 1372 | sleep_time = timeout_start + audit_backlog_wait_time - jiffies;
|
| 1373 | if (sleep_time > 0) {
|
| 1374 | sleep_time = wait_for_auditd(sleep_time);
|
| 1375 | if (sleep_time > 0)
|
| 1376 | continue;
|
| 1377 | }
|
| 1378 | }
|
| 1379 | if (audit_rate_check() && printk_ratelimit())
|
| 1380 | pr_warn("audit_backlog=%d > audit_backlog_limit=%d\n",
|
| 1381 | skb_queue_len(&audit_skb_queue),
|
| 1382 | audit_backlog_limit);
|
| 1383 | audit_log_lost("backlog limit exceeded");
|
| 1384 | audit_backlog_wait_time = audit_backlog_wait_overflow;
|
| 1385 | wake_up(&audit_backlog_wait);
|
| 1386 | return NULL;
|
| 1387 | }
|
| 1388 |
|
| 1389 | if (!reserve)
|
| 1390 | audit_backlog_wait_time = audit_backlog_wait_time_master;
|
| 1391 |
|
| 1392 | ab = audit_buffer_alloc(ctx, gfp_mask, type);
|
| 1393 | if (!ab) {
|
| 1394 | audit_log_lost("out of memory in audit_log_start");
|
| 1395 | return NULL;
|
| 1396 | }
|
| 1397 |
|
| 1398 | audit_get_stamp(ab->ctx, &t, &serial);
|
| 1399 |
|
| 1400 | audit_log_format(ab, "audit(%lu.%03lu:%u): ",
|
| 1401 | t.tv_sec, t.tv_nsec/1000000, serial);
|
| 1402 | return ab;
|
| 1403 | }
|
| 1404 |
|
| 1405 | |
| 1406 | * audit_expand - expand skb in the audit buffer
|
| 1407 | * @ab: audit_buffer
|
| 1408 | * @extra: space to add at tail of the skb
|
| 1409 | *
|
| 1410 | * Returns 0 (no space) on failed expansion, or available space if
|
| 1411 | * successful.
|
| 1412 |
|
| 1413 | static inline int audit_expand(struct audit_buffer *ab, int extra)
|
| 1414 | {
|
| 1415 | struct sk_buff *skb = ab->skb;
|
| 1416 | int oldtail = skb_tailroom(skb);
|
| 1417 | int ret = pskb_expand_head(skb, 0, extra, ab->gfp_mask);
|
| 1418 | int newtail = skb_tailroom(skb);
|
| 1419 |
|
| 1420 | if (ret < 0) {
|
| 1421 | audit_log_lost("out of memory in audit_expand");
|
| 1422 | return 0;
|
| 1423 | }
|
| 1424 |
|
| 1425 | skb->truesize += newtail - oldtail;
|
| 1426 | return newtail;
|
| 1427 | }
|
| 1428 |
|
| 1429 | |
| 1430 | * Format an audit message into the audit buffer. If there isn't enough
|
| 1431 | * room in the audit buffer, more room will be allocated and vsnprint
|
| 1432 | * will be called a second time. Currently, we assume that a printk
|
| 1433 | * can't format message larger than 1024 bytes, so we don't either.
|
| 1434 |
|
| 1435 | static void audit_log_vformat(struct audit_buffer *ab, const char *fmt,
|
| 1436 | va_list args)
|
| 1437 | {
|
| 1438 | int len, avail;
|
| 1439 | struct sk_buff *skb;
|
| 1440 | va_list args2;
|
| 1441 |
|
| 1442 | if (!ab)
|
| 1443 | return;
|
| 1444 |
|
| 1445 | BUG_ON(!ab->skb);
|
| 1446 | skb = ab->skb;
|
| 1447 | avail = skb_tailroom(skb);
|
| 1448 | if (avail == 0) {
|
| 1449 | avail = audit_expand(ab, AUDIT_BUFSIZ);
|
| 1450 | if (!avail)
|
| 1451 | goto out;
|
| 1452 | }
|
| 1453 | va_copy(args2, args);
|
| 1454 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args);
|
| 1455 | if (len >= avail) {
|
| 1456 | |
| 1457 | * here and AUDIT_BUFSIZ is at least 1024, then we can
|
| 1458 | * log everything that printk could have logged.
|
| 1459 | avail = audit_expand(ab,
|
| 1460 | max_t(unsigned, AUDIT_BUFSIZ, 1+len-avail));
|
| 1461 | if (!avail)
|
| 1462 | goto out_va_end;
|
| 1463 | len = vsnprintf(skb_tail_pointer(skb), avail, fmt, args2);
|
| 1464 | }
|
| 1465 | if (len > 0)
|
| 1466 | skb_put(skb, len);
|
| 1467 | out_va_end:
|
| 1468 | va_end(args2);
|
| 1469 | out:
|
| 1470 | return;
|
| 1471 | }
|
| 1472 |
|
| 1473 | |
| 1474 | * audit_log_format - format a message into the audit buffer.
|
| 1475 | * @ab: audit_buffer
|
| 1476 | * @fmt: format string
|
| 1477 | * @...: optional parameters matching @fmt string
|
| 1478 | *
|
| 1479 | * All the work is done in audit_log_vformat.
|
| 1480 |
|
| 1481 | void audit_log_format(struct audit_buffer *ab, const char *fmt, ...)
|
| 1482 | {
|
| 1483 | va_list args;
|
| 1484 |
|
| 1485 | if (!ab)
|
| 1486 | return;
|
| 1487 | va_start(args, fmt);
|
| 1488 | audit_log_vformat(ab, fmt, args);
|
| 1489 | va_end(args);
|
| 1490 | }
|
| 1491 |
|
| 1492 | |
| 1493 | * audit_log_hex - convert a buffer to hex and append it to the audit skb
|
| 1494 | * @ab: the audit_buffer
|
| 1495 | * @buf: buffer to convert to hex
|
| 1496 | * @len: length of @buf to be converted
|
| 1497 | *
|
| 1498 | * No return value; failure to expand is silently ignored.
|
| 1499 | *
|
| 1500 | * This function will take the passed buf and convert it into a string of
|
| 1501 | * ascii hex digits. The new string is placed onto the skb.
|
| 1502 |
|
| 1503 | void audit_log_n_hex(struct audit_buffer *ab, const unsigned char *buf,
|
| 1504 | size_t len)
|
| 1505 | {
|
| 1506 | int i, avail, new_len;
|
| 1507 | unsigned char *ptr;
|
| 1508 | struct sk_buff *skb;
|
| 1509 |
|
| 1510 | if (!ab)
|
| 1511 | return;
|
| 1512 |
|
| 1513 | BUG_ON(!ab->skb);
|
| 1514 | skb = ab->skb;
|
| 1515 | avail = skb_tailroom(skb);
|
| 1516 | new_len = len<<1;
|
| 1517 | if (new_len >= avail) {
|
| 1518 |
|
| 1519 | new_len = AUDIT_BUFSIZ*(((new_len-avail)/AUDIT_BUFSIZ) + 1);
|
| 1520 | avail = audit_expand(ab, new_len);
|
| 1521 | if (!avail)
|
| 1522 | return;
|
| 1523 | }
|
| 1524 |
|
| 1525 | ptr = skb_tail_pointer(skb);
|
| 1526 | for (i = 0; i < len; i++)
|
| 1527 | ptr = hex_byte_pack_upper(ptr, buf[i]);
|
| 1528 | *ptr = 0;
|
| 1529 | skb_put(skb, len << 1);
|
| 1530 | }
|
| 1531 |
|
| 1532 | |
| 1533 | * Format a string of no more than slen characters into the audit buffer,
|
| 1534 | * enclosed in quote marks.
|
| 1535 |
|
| 1536 | void audit_log_n_string(struct audit_buffer *ab, const char *string,
|
| 1537 | size_t slen)
|
| 1538 | {
|
| 1539 | int avail, new_len;
|
| 1540 | unsigned char *ptr;
|
| 1541 | struct sk_buff *skb;
|
| 1542 |
|
| 1543 | if (!ab)
|
| 1544 | return;
|
| 1545 |
|
| 1546 | BUG_ON(!ab->skb);
|
| 1547 | skb = ab->skb;
|
| 1548 | avail = skb_tailroom(skb);
|
| 1549 | new_len = slen + 3;
|
| 1550 | if (new_len > avail) {
|
| 1551 | avail = audit_expand(ab, new_len);
|
| 1552 | if (!avail)
|
| 1553 | return;
|
| 1554 | }
|
| 1555 | ptr = skb_tail_pointer(skb);
|
| 1556 | *ptr++ = '"';
|
| 1557 | memcpy(ptr, string, slen);
|
| 1558 | ptr += slen;
|
| 1559 | *ptr++ = '"';
|
| 1560 | *ptr = 0;
|
| 1561 | skb_put(skb, slen + 2);
|
| 1562 | }
|
| 1563 |
|
| 1564 | |
| 1565 | * audit_string_contains_control - does a string need to be logged in hex
|
| 1566 | * @string: string to be checked
|
| 1567 | * @len: max length of the string to check
|
| 1568 |
|
| 1569 | int audit_string_contains_control(const char *string, size_t len)
|
| 1570 | {
|
| 1571 | const unsigned char *p;
|
| 1572 | for (p = string; p < (const unsigned char *)string + len; p++) {
|
| 1573 | if (*p == '"' || *p < 0x21 || *p > 0x7e)
|
| 1574 | return 1;
|
| 1575 | }
|
| 1576 | return 0;
|
| 1577 | }
|
| 1578 |
|
| 1579 | |
| 1580 | * audit_log_n_untrustedstring - log a string that may contain random characters
|
| 1581 | * @ab: audit_buffer
|
| 1582 | * @len: length of string (not including trailing null)
|
| 1583 | * @string: string to be logged
|
| 1584 | *
|
| 1585 | * This code will escape a string that is passed to it if the string
|
| 1586 | * contains a control character, unprintable character, double quote mark,
|
| 1587 | * or a space. Unescaped strings will start and end with a double quote mark.
|
| 1588 | * Strings that are escaped are printed in hex (2 digits per char).
|
| 1589 | *
|
| 1590 | * The caller specifies the number of characters in the string to log, which may
|
| 1591 | * or may not be the entire string.
|
| 1592 |
|
| 1593 | void audit_log_n_untrustedstring(struct audit_buffer *ab, const char *string,
|
| 1594 | size_t len)
|
| 1595 | {
|
| 1596 | if (audit_string_contains_control(string, len))
|
| 1597 | audit_log_n_hex(ab, string, len);
|
| 1598 | else
|
| 1599 | audit_log_n_string(ab, string, len);
|
| 1600 | }
|
| 1601 |
|
| 1602 | |
| 1603 | * audit_log_untrustedstring - log a string that may contain random characters
|
| 1604 | * @ab: audit_buffer
|
| 1605 | * @string: string to be logged
|
| 1606 | *
|
| 1607 | * Same as audit_log_n_untrustedstring(), except that strlen is used to
|
| 1608 | * determine string length.
|
| 1609 |
|
| 1610 | void audit_log_untrustedstring(struct audit_buffer *ab, const char *string)
|
| 1611 | {
|
| 1612 | audit_log_n_untrustedstring(ab, string, strlen(string));
|
| 1613 | }
|
| 1614 |
|
| 1615 |
|
| 1616 | void audit_log_d_path(struct audit_buffer *ab, const char *prefix,
|
| 1617 | const struct path *path)
|
| 1618 | {
|
| 1619 | char *p, *pathname;
|
| 1620 |
|
| 1621 | if (prefix)
|
| 1622 | audit_log_format(ab, "%s", prefix);
|
| 1623 |
|
| 1624 |
|
| 1625 | pathname = kmalloc(PATH_MAX+11, ab->gfp_mask);
|
| 1626 | if (!pathname) {
|
| 1627 | audit_log_string(ab, "<no_memory>");
|
| 1628 | return;
|
| 1629 | }
|
| 1630 | p = d_path(path, pathname, PATH_MAX+11);
|
| 1631 | if (IS_ERR(p)) {
|
| 1632 |
|
| 1633 | audit_log_string(ab, "<too_long>");
|
| 1634 | } else
|
| 1635 | audit_log_untrustedstring(ab, p);
|
| 1636 | kfree(pathname);
|
| 1637 | }
|
| 1638 |
|
| 1639 | void audit_log_session_info(struct audit_buffer *ab)
|
| 1640 | {
|
| 1641 | unsigned int sessionid = audit_get_sessionid(current);
|
| 1642 | uid_t auid = from_kuid(&init_user_ns, audit_get_loginuid(current));
|
| 1643 |
|
| 1644 | audit_log_format(ab, " auid=%u ses=%u", auid, sessionid);
|
| 1645 | }
|
| 1646 |
|
| 1647 | void audit_log_key(struct audit_buffer *ab, char *key)
|
| 1648 | {
|
| 1649 | audit_log_format(ab, " key=");
|
| 1650 | if (key)
|
| 1651 | audit_log_untrustedstring(ab, key);
|
| 1652 | else
|
| 1653 | audit_log_format(ab, "(null)");
|
| 1654 | }
|
| 1655 |
|
| 1656 | void audit_log_cap(struct audit_buffer *ab, char *prefix, kernel_cap_t *cap)
|
| 1657 | {
|
| 1658 | int i;
|
| 1659 |
|
| 1660 | audit_log_format(ab, " %s=", prefix);
|
| 1661 | CAP_FOR_EACH_U32(i) {
|
| 1662 | audit_log_format(ab, "%08x",
|
| 1663 | cap->cap[CAP_LAST_U32 - i]);
|
| 1664 | }
|
| 1665 | }
|
| 1666 |
|
| 1667 | static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
|
| 1668 | {
|
| 1669 | kernel_cap_t *perm = &name->fcap.permitted;
|
| 1670 | kernel_cap_t *inh = &name->fcap.inheritable;
|
| 1671 | int log = 0;
|
| 1672 |
|
| 1673 | if (!cap_isclear(*perm)) {
|
| 1674 | audit_log_cap(ab, "cap_fp", perm);
|
| 1675 | log = 1;
|
| 1676 | }
|
| 1677 | if (!cap_isclear(*inh)) {
|
| 1678 | audit_log_cap(ab, "cap_fi", inh);
|
| 1679 | log = 1;
|
| 1680 | }
|
| 1681 |
|
| 1682 | if (log)
|
| 1683 | audit_log_format(ab, " cap_fe=%d cap_fver=%x",
|
| 1684 | name->fcap.fE, name->fcap_ver);
|
| 1685 | }
|
| 1686 |
|
| 1687 | static inline int audit_copy_fcaps(struct audit_names *name,
|
| 1688 | const struct dentry *dentry)
|
| 1689 | {
|
| 1690 | struct cpu_vfs_cap_data caps;
|
| 1691 | int rc;
|
| 1692 |
|
| 1693 | if (!dentry)
|
| 1694 | return 0;
|
| 1695 |
|
| 1696 | rc = get_vfs_caps_from_disk(dentry, &caps);
|
| 1697 | if (rc)
|
| 1698 | return rc;
|
| 1699 |
|
| 1700 | name->fcap.permitted = caps.permitted;
|
| 1701 | name->fcap.inheritable = caps.inheritable;
|
| 1702 | name->fcap.fE = !!(caps.magic_etc & VFS_CAP_FLAGS_EFFECTIVE);
|
| 1703 | name->fcap_ver = (caps.magic_etc & VFS_CAP_REVISION_MASK) >>
|
| 1704 | VFS_CAP_REVISION_SHIFT;
|
| 1705 |
|
| 1706 | return 0;
|
| 1707 | }
|
| 1708 |
|
| 1709 |
|
| 1710 | void audit_copy_inode(struct audit_names *name, const struct dentry *dentry,
|
| 1711 | const struct inode *inode)
|
| 1712 | {
|
| 1713 | name->ino = inode->i_ino;
|
| 1714 | name->dev = inode->i_sb->s_dev;
|
| 1715 | name->mode = inode->i_mode;
|
| 1716 | name->uid = inode->i_uid;
|
| 1717 | name->gid = inode->i_gid;
|
| 1718 | name->rdev = inode->i_rdev;
|
| 1719 | security_inode_getsecid(inode, &name->osid);
|
| 1720 | audit_copy_fcaps(name, dentry);
|
| 1721 | }
|
| 1722 |
|
| 1723 | |
| 1724 | * audit_log_name - produce AUDIT_PATH record from struct audit_names
|
| 1725 | * @context: audit_context for the task
|
| 1726 | * @n: audit_names structure with reportable details
|
| 1727 | * @path: optional path to report instead of audit_names->name
|
| 1728 | * @record_num: record number to report when handling a list of names
|
| 1729 | * @call_panic: optional pointer to int that will be updated if secid fails
|
| 1730 |
|
| 1731 | void audit_log_name(struct audit_context *context, struct audit_names *n,
|
| 1732 | struct path *path, int record_num, int *call_panic)
|
| 1733 | {
|
| 1734 | struct audit_buffer *ab;
|
| 1735 | ab = audit_log_start(context, GFP_KERNEL, AUDIT_PATH);
|
| 1736 | if (!ab)
|
| 1737 | return;
|
| 1738 |
|
| 1739 | audit_log_format(ab, "item=%d", record_num);
|
| 1740 |
|
| 1741 | if (path)
|
| 1742 | audit_log_d_path(ab, " name=", path);
|
| 1743 | else if (n->name) {
|
| 1744 | switch (n->name_len) {
|
| 1745 | case AUDIT_NAME_FULL:
|
| 1746 |
|
| 1747 | audit_log_format(ab, " name=");
|
| 1748 | audit_log_untrustedstring(ab, n->name->name);
|
| 1749 | break;
|
| 1750 | case 0:
|
| 1751 | |
| 1752 | * directory component is the cwd
|
| 1753 | audit_log_d_path(ab, " name=", &context->pwd);
|
| 1754 | break;
|
| 1755 | default:
|
| 1756 |
|
| 1757 | audit_log_format(ab, " name=");
|
| 1758 | audit_log_n_untrustedstring(ab, n->name->name,
|
| 1759 | n->name_len);
|
| 1760 | }
|
| 1761 | } else
|
| 1762 | audit_log_format(ab, " name=(null)");
|
| 1763 |
|
| 1764 | if (n->ino != AUDIT_INO_UNSET)
|
| 1765 | audit_log_format(ab, " inode=%lu"
|
| 1766 | " dev=%02x:%02x mode=%#ho"
|
| 1767 | " ouid=%u ogid=%u rdev=%02x:%02x",
|
| 1768 | n->ino,
|
| 1769 | MAJOR(n->dev),
|
| 1770 | MINOR(n->dev),
|
| 1771 | n->mode,
|
| 1772 | from_kuid(&init_user_ns, n->uid),
|
| 1773 | from_kgid(&init_user_ns, n->gid),
|
| 1774 | MAJOR(n->rdev),
|
| 1775 | MINOR(n->rdev));
|
| 1776 | if (n->osid != 0) {
|
| 1777 | char *ctx = NULL;
|
| 1778 | u32 len;
|
| 1779 | if (security_secid_to_secctx(
|
| 1780 | n->osid, &ctx, &len)) {
|
| 1781 | audit_log_format(ab, " osid=%u", n->osid);
|
| 1782 | if (call_panic)
|
| 1783 | *call_panic = 2;
|
| 1784 | } else {
|
| 1785 | audit_log_format(ab, " obj=%s", ctx);
|
| 1786 | security_release_secctx(ctx, len);
|
| 1787 | }
|
| 1788 | }
|
| 1789 |
|
| 1790 |
|
| 1791 | audit_log_format(ab, " nametype=");
|
| 1792 | switch(n->type) {
|
| 1793 | case AUDIT_TYPE_NORMAL:
|
| 1794 | audit_log_format(ab, "NORMAL");
|
| 1795 | break;
|
| 1796 | case AUDIT_TYPE_PARENT:
|
| 1797 | audit_log_format(ab, "PARENT");
|
| 1798 | break;
|
| 1799 | case AUDIT_TYPE_CHILD_DELETE:
|
| 1800 | audit_log_format(ab, "DELETE");
|
| 1801 | break;
|
| 1802 | case AUDIT_TYPE_CHILD_CREATE:
|
| 1803 | audit_log_format(ab, "CREATE");
|
| 1804 | break;
|
| 1805 | default:
|
| 1806 | audit_log_format(ab, "UNKNOWN");
|
| 1807 | break;
|
| 1808 | }
|
| 1809 |
|
| 1810 | audit_log_fcaps(ab, n);
|
| 1811 | audit_log_end(ab);
|
| 1812 | }
|
| 1813 |
|
| 1814 | int audit_log_task_context(struct audit_buffer *ab)
|
| 1815 | {
|
| 1816 | char *ctx = NULL;
|
| 1817 | unsigned len;
|
| 1818 | int error;
|
| 1819 | u32 sid;
|
| 1820 |
|
| 1821 | security_task_getsecid(current, &sid);
|
| 1822 | if (!sid)
|
| 1823 | return 0;
|
| 1824 |
|
| 1825 | error = security_secid_to_secctx(sid, &ctx, &len);
|
| 1826 | if (error) {
|
| 1827 | if (error != -EINVAL)
|
| 1828 | goto error_path;
|
| 1829 | return 0;
|
| 1830 | }
|
| 1831 |
|
| 1832 | audit_log_format(ab, " subj=%s", ctx);
|
| 1833 | security_release_secctx(ctx, len);
|
| 1834 | return 0;
|
| 1835 |
|
| 1836 | error_path:
|
| 1837 | audit_panic("error in audit_log_task_context");
|
| 1838 | return error;
|
| 1839 | }
|
| 1840 | EXPORT_SYMBOL(audit_log_task_context);
|
| 1841 |
|
| 1842 | void audit_log_d_path_exe(struct audit_buffer *ab,
|
| 1843 | struct mm_struct *mm)
|
| 1844 | {
|
| 1845 | struct file *exe_file;
|
| 1846 |
|
| 1847 | if (!mm)
|
| 1848 | goto out_null;
|
| 1849 |
|
| 1850 | exe_file = get_mm_exe_file(mm);
|
| 1851 | if (!exe_file)
|
| 1852 | goto out_null;
|
| 1853 |
|
| 1854 | audit_log_d_path(ab, " exe=", &exe_file->f_path);
|
| 1855 | fput(exe_file);
|
| 1856 | return;
|
| 1857 | out_null:
|
| 1858 | audit_log_format(ab, " exe=(null)");
|
| 1859 | }
|
| 1860 |
|
| 1861 | void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
|
| 1862 | {
|
| 1863 | const struct cred *cred;
|
| 1864 | char comm[sizeof(tsk->comm)];
|
| 1865 | char *tty;
|
| 1866 |
|
| 1867 | if (!ab)
|
| 1868 | return;
|
| 1869 |
|
| 1870 |
|
| 1871 | cred = current_cred();
|
| 1872 |
|
| 1873 | spin_lock_irq(&tsk->sighand->siglock);
|
| 1874 | if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
|
| 1875 | tty = tsk->signal->tty->name;
|
| 1876 | else
|
| 1877 | tty = "(none)";
|
| 1878 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 1879 |
|
| 1880 | audit_log_format(ab,
|
| 1881 | " ppid=%d pid=%d auid=%u uid=%u gid=%u"
|
| 1882 | " euid=%u suid=%u fsuid=%u"
|
| 1883 | " egid=%u sgid=%u fsgid=%u tty=%s ses=%u",
|
| 1884 | task_ppid_nr(tsk),
|
| 1885 | task_pid_nr(tsk),
|
| 1886 | from_kuid(&init_user_ns, audit_get_loginuid(tsk)),
|
| 1887 | from_kuid(&init_user_ns, cred->uid),
|
| 1888 | from_kgid(&init_user_ns, cred->gid),
|
| 1889 | from_kuid(&init_user_ns, cred->euid),
|
| 1890 | from_kuid(&init_user_ns, cred->suid),
|
| 1891 | from_kuid(&init_user_ns, cred->fsuid),
|
| 1892 | from_kgid(&init_user_ns, cred->egid),
|
| 1893 | from_kgid(&init_user_ns, cred->sgid),
|
| 1894 | from_kgid(&init_user_ns, cred->fsgid),
|
| 1895 | tty, audit_get_sessionid(tsk));
|
| 1896 |
|
| 1897 | audit_log_format(ab, " comm=");
|
| 1898 | audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
|
| 1899 |
|
| 1900 | audit_log_d_path_exe(ab, tsk->mm);
|
| 1901 | audit_log_task_context(ab);
|
| 1902 | }
|
| 1903 | EXPORT_SYMBOL(audit_log_task_info);
|
| 1904 |
|
| 1905 | |
| 1906 | * audit_log_link_denied - report a link restriction denial
|
| 1907 | * @operation: specific link operation
|
| 1908 | * @link: the path that triggered the restriction
|
| 1909 |
|
| 1910 | void audit_log_link_denied(const char *operation, struct path *link)
|
| 1911 | {
|
| 1912 | struct audit_buffer *ab;
|
| 1913 | struct audit_names *name;
|
| 1914 |
|
| 1915 | name = kzalloc(sizeof(*name), GFP_NOFS);
|
| 1916 | if (!name)
|
| 1917 | return;
|
| 1918 |
|
| 1919 |
|
| 1920 | ab = audit_log_start(current->audit_context, GFP_KERNEL,
|
| 1921 | AUDIT_ANOM_LINK);
|
| 1922 | if (!ab)
|
| 1923 | goto out;
|
| 1924 | audit_log_format(ab, "op=%s", operation);
|
| 1925 | audit_log_task_info(ab, current);
|
| 1926 | audit_log_format(ab, " res=0");
|
| 1927 | audit_log_end(ab);
|
| 1928 |
|
| 1929 |
|
| 1930 | name->type = AUDIT_TYPE_NORMAL;
|
| 1931 | audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
|
| 1932 | audit_log_name(current->audit_context, name, link, 0, NULL);
|
| 1933 | out:
|
| 1934 | kfree(name);
|
| 1935 | }
|
| 1936 |
|
| 1937 | |
| 1938 | * audit_log_end - end one audit record
|
| 1939 | * @ab: the audit_buffer
|
| 1940 | *
|
| 1941 | * netlink_unicast() cannot be called inside an irq context because it blocks
|
| 1942 | * (last arg, flags, is not set to MSG_DONTWAIT), so the audit buffer is placed
|
| 1943 | * on a queue and a tasklet is scheduled to remove them from the queue outside
|
| 1944 | * the irq context. May be called in any context.
|
| 1945 |
|
| 1946 | void audit_log_end(struct audit_buffer *ab)
|
| 1947 | {
|
| 1948 | if (!ab)
|
| 1949 | return;
|
| 1950 | if (!audit_rate_check()) {
|
| 1951 | audit_log_lost("rate limit exceeded");
|
| 1952 | } else {
|
| 1953 | struct nlmsghdr *nlh = nlmsg_hdr(ab->skb);
|
| 1954 |
|
| 1955 | nlh->nlmsg_len = ab->skb->len;
|
| 1956 | kauditd_send_multicast_skb(ab->skb, ab->gfp_mask);
|
| 1957 |
|
| 1958 | |
| 1959 | * The original kaudit unicast socket sends up messages with
|
| 1960 | * nlmsg_len set to the payload length rather than the entire
|
| 1961 | * message length. This breaks the standard set by netlink.
|
| 1962 | * The existing auditd daemon assumes this breakage. Fixing
|
| 1963 | * this would require co-ordinating a change in the established
|
| 1964 | * protocol between the kaudit kernel subsystem and the auditd
|
| 1965 | * userspace code.
|
| 1966 |
|
| 1967 | nlh->nlmsg_len -= NLMSG_HDRLEN;
|
| 1968 |
|
| 1969 | if (audit_pid) {
|
| 1970 | skb_queue_tail(&audit_skb_queue, ab->skb);
|
| 1971 | wake_up_interruptible(&kauditd_wait);
|
| 1972 | } else {
|
| 1973 | audit_printk_skb(ab->skb);
|
| 1974 | }
|
| 1975 | ab->skb = NULL;
|
| 1976 | }
|
| 1977 | audit_buffer_free(ab);
|
| 1978 | }
|
| 1979 |
|
| 1980 | |
| 1981 | * audit_log - Log an audit record
|
| 1982 | * @ctx: audit context
|
| 1983 | * @gfp_mask: type of allocation
|
| 1984 | * @type: audit message type
|
| 1985 | * @fmt: format string to use
|
| 1986 | * @...: variable parameters matching the format string
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| 1987 | *
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| 1988 | * This is a convenience function that calls audit_log_start,
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| 1989 | * audit_log_vformat, and audit_log_end. It may be called
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| 1990 | * in any context.
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| 1991 |
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| 1992 | void audit_log(struct audit_context *ctx, gfp_t gfp_mask, int type,
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| 1993 | const char *fmt, ...)
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| 1994 | {
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| 1995 | struct audit_buffer *ab;
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| 1996 | va_list args;
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| 1997 |
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| 1998 | ab = audit_log_start(ctx, gfp_mask, type);
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| 1999 | if (ab) {
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| 2000 | va_start(args, fmt);
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| 2001 | audit_log_vformat(ab, fmt, args);
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| 2002 | va_end(args);
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| 2003 | audit_log_end(ab);
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| 2004 | }
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| 2005 | }
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| 2006 |
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| 2007 | #ifdef CONFIG_SECURITY
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| 2008 | |
| 2009 | * audit_log_secctx - Converts and logs SELinux context
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| 2010 | * @ab: audit_buffer
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| 2011 | * @secid: security number
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| 2012 | *
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| 2013 | * This is a helper function that calls security_secid_to_secctx to convert
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| 2014 | * secid to secctx and then adds the (converted) SELinux context to the audit
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| 2015 | * log by calling audit_log_format, thus also preventing leak of internal secid
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| 2016 | * to userspace. If secid cannot be converted audit_panic is called.
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| 2017 |
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| 2018 | void audit_log_secctx(struct audit_buffer *ab, u32 secid)
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| 2019 | {
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| 2020 | u32 len;
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| 2021 | char *secctx;
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| 2022 |
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| 2023 | if (security_secid_to_secctx(secid, &secctx, &len)) {
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| 2024 | audit_panic("Cannot convert secid to context");
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| 2025 | } else {
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| 2026 | audit_log_format(ab, " obj=%s", secctx);
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| 2027 | security_release_secctx(secctx, len);
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| 2028 | }
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| 2029 | }
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| 2030 | EXPORT_SYMBOL(audit_log_secctx);
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| 2031 | #endif
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| 2032 |
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| 2033 | EXPORT_SYMBOL(audit_log_start);
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| 2034 | EXPORT_SYMBOL(audit_log_end);
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| 2035 | EXPORT_SYMBOL(audit_log_format);
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| 2036 | EXPORT_SYMBOL(audit_log);
|