2 * Creating audit events from TTY input.
4 * Copyright (C) 2007 Red Hat, Inc. All rights reserved. This copyrighted
5 * material is made available to anyone wishing to use, modify, copy, or
6 * redistribute it subject to the terms and conditions of the GNU General
9 * Authors: Miloslav Trmac <mitr@redhat.com>
12 #include <linux/audit.h>
13 #include <linux/tty.h>
15 struct tty_audit_buf {
17 struct mutex mutex; /* Protects all data below */
18 int major, minor; /* The TTY which the data is from */
21 unsigned char *data; /* Allocated size N_TTY_BUF_SIZE */
24 static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor,
27 struct tty_audit_buf *buf;
29 buf = kmalloc(sizeof(*buf), GFP_KERNEL);
32 buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
35 atomic_set(&buf->count, 1);
36 mutex_init(&buf->mutex);
49 static void tty_audit_buf_free(struct tty_audit_buf *buf)
51 WARN_ON(buf->valid != 0);
56 static void tty_audit_buf_put(struct tty_audit_buf *buf)
58 if (atomic_dec_and_test(&buf->count))
59 tty_audit_buf_free(buf);
62 static void tty_audit_log(const char *description, struct task_struct *tsk,
63 uid_t loginuid, unsigned sessionid, int major,
64 int minor, unsigned char *data, size_t size)
66 struct audit_buffer *ab;
68 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY);
70 char name[sizeof(tsk->comm)];
71 uid_t uid = task_uid(tsk);
73 audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u "
74 "major=%d minor=%d comm=", description,
75 tsk->pid, uid, loginuid, sessionid,
77 get_task_comm(name, tsk);
78 audit_log_untrustedstring(ab, name);
79 audit_log_format(ab, " data=");
80 audit_log_n_hex(ab, data, size);
86 * tty_audit_buf_push - Push buffered data out
88 * Generate an audit message from the contents of @buf, which is owned by
89 * @tsk with @loginuid. @buf->mutex must be locked.
91 static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid,
92 unsigned int sessionid,
93 struct tty_audit_buf *buf)
97 if (audit_enabled == 0)
99 tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor,
100 buf->data, buf->valid);
105 * tty_audit_buf_push_current - Push buffered data out
107 * Generate an audit message from the contents of @buf, which is owned by
108 * the current task. @buf->mutex must be locked.
110 static void tty_audit_buf_push_current(struct tty_audit_buf *buf)
112 uid_t auid = audit_get_loginuid(current);
113 unsigned int sessionid = audit_get_sessionid(current);
114 tty_audit_buf_push(current, auid, sessionid, buf);
118 * tty_audit_exit - Handle a task exit
120 * Make sure all buffered data is written out and deallocate the buffer.
121 * Only needs to be called if current->signal->tty_audit_buf != %NULL.
123 void tty_audit_exit(void)
125 struct tty_audit_buf *buf;
127 spin_lock_irq(¤t->sighand->siglock);
128 buf = current->signal->tty_audit_buf;
129 current->signal->tty_audit_buf = NULL;
130 spin_unlock_irq(¤t->sighand->siglock);
134 mutex_lock(&buf->mutex);
135 tty_audit_buf_push_current(buf);
136 mutex_unlock(&buf->mutex);
138 tty_audit_buf_put(buf);
142 * tty_audit_fork - Copy TTY audit state for a new task
144 * Set up TTY audit state in @sig from current. @sig needs no locking.
146 void tty_audit_fork(struct signal_struct *sig)
148 spin_lock_irq(¤t->sighand->siglock);
149 sig->audit_tty = current->signal->audit_tty;
150 spin_unlock_irq(¤t->sighand->siglock);
154 * tty_audit_tiocsti - Log TIOCSTI
156 void tty_audit_tiocsti(struct tty_struct *tty, char ch)
158 struct tty_audit_buf *buf;
159 int major, minor, should_audit;
161 spin_lock_irq(¤t->sighand->siglock);
162 should_audit = current->signal->audit_tty;
163 buf = current->signal->tty_audit_buf;
165 atomic_inc(&buf->count);
166 spin_unlock_irq(¤t->sighand->siglock);
168 major = tty->driver->major;
169 minor = tty->driver->minor_start + tty->index;
171 mutex_lock(&buf->mutex);
172 if (buf->major == major && buf->minor == minor)
173 tty_audit_buf_push_current(buf);
174 mutex_unlock(&buf->mutex);
175 tty_audit_buf_put(buf);
178 if (should_audit && audit_enabled) {
180 unsigned int sessionid;
182 auid = audit_get_loginuid(current);
183 sessionid = audit_get_sessionid(current);
184 tty_audit_log("ioctl=TIOCSTI", current, auid, sessionid, major,
190 * tty_audit_push_task - Flush task's pending audit data
192 void tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid)
194 struct tty_audit_buf *buf;
196 spin_lock_irq(&tsk->sighand->siglock);
197 buf = tsk->signal->tty_audit_buf;
199 atomic_inc(&buf->count);
200 spin_unlock_irq(&tsk->sighand->siglock);
204 mutex_lock(&buf->mutex);
205 tty_audit_buf_push(tsk, loginuid, sessionid, buf);
206 mutex_unlock(&buf->mutex);
208 tty_audit_buf_put(buf);
212 * tty_audit_buf_get - Get an audit buffer.
214 * Get an audit buffer for @tty, allocate it if necessary. Return %NULL
215 * if TTY auditing is disabled or out of memory. Otherwise, return a new
216 * reference to the buffer.
218 static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
220 struct tty_audit_buf *buf, *buf2;
224 spin_lock_irq(¤t->sighand->siglock);
225 if (likely(!current->signal->audit_tty))
227 buf = current->signal->tty_audit_buf;
229 atomic_inc(&buf->count);
232 spin_unlock_irq(¤t->sighand->siglock);
234 buf2 = tty_audit_buf_alloc(tty->driver->major,
235 tty->driver->minor_start + tty->index,
238 audit_log_lost("out of memory in TTY auditing");
242 spin_lock_irq(¤t->sighand->siglock);
243 if (!current->signal->audit_tty)
245 buf = current->signal->tty_audit_buf;
247 current->signal->tty_audit_buf = buf2;
251 atomic_inc(&buf->count);
254 spin_unlock_irq(¤t->sighand->siglock);
256 tty_audit_buf_free(buf2);
261 * tty_audit_add_data - Add data for TTY auditing.
263 * Audit @data of @size from @tty, if necessary.
265 void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
268 struct tty_audit_buf *buf;
271 if (unlikely(size == 0))
274 if (tty->driver->type == TTY_DRIVER_TYPE_PTY
275 && tty->driver->subtype == PTY_TYPE_MASTER)
278 buf = tty_audit_buf_get(tty);
282 mutex_lock(&buf->mutex);
283 major = tty->driver->major;
284 minor = tty->driver->minor_start + tty->index;
285 if (buf->major != major || buf->minor != minor
286 || buf->icanon != tty->icanon) {
287 tty_audit_buf_push_current(buf);
290 buf->icanon = tty->icanon;
295 run = N_TTY_BUF_SIZE - buf->valid;
298 memcpy(buf->data + buf->valid, data, run);
302 if (buf->valid == N_TTY_BUF_SIZE)
303 tty_audit_buf_push_current(buf);
305 mutex_unlock(&buf->mutex);
306 tty_audit_buf_put(buf);
310 * tty_audit_push - Push buffered data out
312 * Make sure no audit data is pending for @tty on the current process.
314 void tty_audit_push(struct tty_struct *tty)
316 struct tty_audit_buf *buf;
318 spin_lock_irq(¤t->sighand->siglock);
319 if (likely(!current->signal->audit_tty)) {
320 spin_unlock_irq(¤t->sighand->siglock);
323 buf = current->signal->tty_audit_buf;
325 atomic_inc(&buf->count);
326 spin_unlock_irq(¤t->sighand->siglock);
331 major = tty->driver->major;
332 minor = tty->driver->minor_start + tty->index;
333 mutex_lock(&buf->mutex);
334 if (buf->major == major && buf->minor == minor)
335 tty_audit_buf_push_current(buf);
336 mutex_unlock(&buf->mutex);
337 tty_audit_buf_put(buf);