perf: Do not export power_frequency, but power_start event
[linux-2.6.git] / drivers / tty / tty_audit.c
1 /*
2  * Creating audit events from TTY input.
3  *
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
7  * Public License v.2.
8  *
9  * Authors: Miloslav Trmac <mitr@redhat.com>
10  */
11
12 #include <linux/audit.h>
13 #include <linux/slab.h>
14 #include <linux/tty.h>
15
16 struct tty_audit_buf {
17         atomic_t count;
18         struct mutex mutex;     /* Protects all data below */
19         int major, minor;       /* The TTY which the data is from */
20         unsigned icanon:1;
21         size_t valid;
22         unsigned char *data;    /* Allocated size N_TTY_BUF_SIZE */
23 };
24
25 static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor,
26                                                  int icanon)
27 {
28         struct tty_audit_buf *buf;
29
30         buf = kmalloc(sizeof(*buf), GFP_KERNEL);
31         if (!buf)
32                 goto err;
33         buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
34         if (!buf->data)
35                 goto err_buf;
36         atomic_set(&buf->count, 1);
37         mutex_init(&buf->mutex);
38         buf->major = major;
39         buf->minor = minor;
40         buf->icanon = icanon;
41         buf->valid = 0;
42         return buf;
43
44 err_buf:
45         kfree(buf);
46 err:
47         return NULL;
48 }
49
50 static void tty_audit_buf_free(struct tty_audit_buf *buf)
51 {
52         WARN_ON(buf->valid != 0);
53         kfree(buf->data);
54         kfree(buf);
55 }
56
57 static void tty_audit_buf_put(struct tty_audit_buf *buf)
58 {
59         if (atomic_dec_and_test(&buf->count))
60                 tty_audit_buf_free(buf);
61 }
62
63 static void tty_audit_log(const char *description, struct task_struct *tsk,
64                           uid_t loginuid, unsigned sessionid, int major,
65                           int minor, unsigned char *data, size_t size)
66 {
67         struct audit_buffer *ab;
68
69         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY);
70         if (ab) {
71                 char name[sizeof(tsk->comm)];
72                 uid_t uid = task_uid(tsk);
73
74                 audit_log_format(ab, "%s pid=%u uid=%u auid=%u ses=%u "
75                                  "major=%d minor=%d comm=", description,
76                                  tsk->pid, uid, loginuid, sessionid,
77                                  major, minor);
78                 get_task_comm(name, tsk);
79                 audit_log_untrustedstring(ab, name);
80                 audit_log_format(ab, " data=");
81                 audit_log_n_hex(ab, data, size);
82                 audit_log_end(ab);
83         }
84 }
85
86 /**
87  *      tty_audit_buf_push      -       Push buffered data out
88  *
89  *      Generate an audit message from the contents of @buf, which is owned by
90  *      @tsk with @loginuid.  @buf->mutex must be locked.
91  */
92 static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid,
93                                unsigned int sessionid,
94                                struct tty_audit_buf *buf)
95 {
96         if (buf->valid == 0)
97                 return;
98         if (audit_enabled == 0)
99                 return;
100         tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor,
101                       buf->data, buf->valid);
102         buf->valid = 0;
103 }
104
105 /**
106  *      tty_audit_buf_push_current      -       Push buffered data out
107  *
108  *      Generate an audit message from the contents of @buf, which is owned by
109  *      the current task.  @buf->mutex must be locked.
110  */
111 static void tty_audit_buf_push_current(struct tty_audit_buf *buf)
112 {
113         uid_t auid = audit_get_loginuid(current);
114         unsigned int sessionid = audit_get_sessionid(current);
115         tty_audit_buf_push(current, auid, sessionid, buf);
116 }
117
118 /**
119  *      tty_audit_exit  -       Handle a task exit
120  *
121  *      Make sure all buffered data is written out and deallocate the buffer.
122  *      Only needs to be called if current->signal->tty_audit_buf != %NULL.
123  */
124 void tty_audit_exit(void)
125 {
126         struct tty_audit_buf *buf;
127
128         spin_lock_irq(&current->sighand->siglock);
129         buf = current->signal->tty_audit_buf;
130         current->signal->tty_audit_buf = NULL;
131         spin_unlock_irq(&current->sighand->siglock);
132         if (!buf)
133                 return;
134
135         mutex_lock(&buf->mutex);
136         tty_audit_buf_push_current(buf);
137         mutex_unlock(&buf->mutex);
138
139         tty_audit_buf_put(buf);
140 }
141
142 /**
143  *      tty_audit_fork  -       Copy TTY audit state for a new task
144  *
145  *      Set up TTY audit state in @sig from current.  @sig needs no locking.
146  */
147 void tty_audit_fork(struct signal_struct *sig)
148 {
149         spin_lock_irq(&current->sighand->siglock);
150         sig->audit_tty = current->signal->audit_tty;
151         spin_unlock_irq(&current->sighand->siglock);
152 }
153
154 /**
155  *      tty_audit_tiocsti       -       Log TIOCSTI
156  */
157 void tty_audit_tiocsti(struct tty_struct *tty, char ch)
158 {
159         struct tty_audit_buf *buf;
160         int major, minor, should_audit;
161
162         spin_lock_irq(&current->sighand->siglock);
163         should_audit = current->signal->audit_tty;
164         buf = current->signal->tty_audit_buf;
165         if (buf)
166                 atomic_inc(&buf->count);
167         spin_unlock_irq(&current->sighand->siglock);
168
169         major = tty->driver->major;
170         minor = tty->driver->minor_start + tty->index;
171         if (buf) {
172                 mutex_lock(&buf->mutex);
173                 if (buf->major == major && buf->minor == minor)
174                         tty_audit_buf_push_current(buf);
175                 mutex_unlock(&buf->mutex);
176                 tty_audit_buf_put(buf);
177         }
178
179         if (should_audit && audit_enabled) {
180                 uid_t auid;
181                 unsigned int sessionid;
182
183                 auid = audit_get_loginuid(current);
184                 sessionid = audit_get_sessionid(current);
185                 tty_audit_log("ioctl=TIOCSTI", current, auid, sessionid, major,
186                               minor, &ch, 1);
187         }
188 }
189
190 /**
191  * tty_audit_push_task  -       Flush task's pending audit data
192  * @tsk:                task pointer
193  * @loginuid:           sender login uid
194  * @sessionid:          sender session id
195  *
196  * Called with a ref on @tsk held. Try to lock sighand and get a
197  * reference to the tty audit buffer if available.
198  * Flush the buffer or return an appropriate error code.
199  */
200 int tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid)
201 {
202         struct tty_audit_buf *buf = ERR_PTR(-EPERM);
203         unsigned long flags;
204
205         if (!lock_task_sighand(tsk, &flags))
206                 return -ESRCH;
207
208         if (tsk->signal->audit_tty) {
209                 buf = tsk->signal->tty_audit_buf;
210                 if (buf)
211                         atomic_inc(&buf->count);
212         }
213         unlock_task_sighand(tsk, &flags);
214
215         /*
216          * Return 0 when signal->audit_tty set
217          * but tsk->signal->tty_audit_buf == NULL.
218          */
219         if (!buf || IS_ERR(buf))
220                 return PTR_ERR(buf);
221
222         mutex_lock(&buf->mutex);
223         tty_audit_buf_push(tsk, loginuid, sessionid, buf);
224         mutex_unlock(&buf->mutex);
225
226         tty_audit_buf_put(buf);
227         return 0;
228 }
229
230 /**
231  *      tty_audit_buf_get       -       Get an audit buffer.
232  *
233  *      Get an audit buffer for @tty, allocate it if necessary.  Return %NULL
234  *      if TTY auditing is disabled or out of memory.  Otherwise, return a new
235  *      reference to the buffer.
236  */
237 static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
238 {
239         struct tty_audit_buf *buf, *buf2;
240
241         buf = NULL;
242         buf2 = NULL;
243         spin_lock_irq(&current->sighand->siglock);
244         if (likely(!current->signal->audit_tty))
245                 goto out;
246         buf = current->signal->tty_audit_buf;
247         if (buf) {
248                 atomic_inc(&buf->count);
249                 goto out;
250         }
251         spin_unlock_irq(&current->sighand->siglock);
252
253         buf2 = tty_audit_buf_alloc(tty->driver->major,
254                                    tty->driver->minor_start + tty->index,
255                                    tty->icanon);
256         if (buf2 == NULL) {
257                 audit_log_lost("out of memory in TTY auditing");
258                 return NULL;
259         }
260
261         spin_lock_irq(&current->sighand->siglock);
262         if (!current->signal->audit_tty)
263                 goto out;
264         buf = current->signal->tty_audit_buf;
265         if (!buf) {
266                 current->signal->tty_audit_buf = buf2;
267                 buf = buf2;
268                 buf2 = NULL;
269         }
270         atomic_inc(&buf->count);
271         /* Fall through */
272  out:
273         spin_unlock_irq(&current->sighand->siglock);
274         if (buf2)
275                 tty_audit_buf_free(buf2);
276         return buf;
277 }
278
279 /**
280  *      tty_audit_add_data      -       Add data for TTY auditing.
281  *
282  *      Audit @data of @size from @tty, if necessary.
283  */
284 void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
285                         size_t size)
286 {
287         struct tty_audit_buf *buf;
288         int major, minor;
289
290         if (unlikely(size == 0))
291                 return;
292
293         if (tty->driver->type == TTY_DRIVER_TYPE_PTY
294             && tty->driver->subtype == PTY_TYPE_MASTER)
295                 return;
296
297         buf = tty_audit_buf_get(tty);
298         if (!buf)
299                 return;
300
301         mutex_lock(&buf->mutex);
302         major = tty->driver->major;
303         minor = tty->driver->minor_start + tty->index;
304         if (buf->major != major || buf->minor != minor
305             || buf->icanon != tty->icanon) {
306                 tty_audit_buf_push_current(buf);
307                 buf->major = major;
308                 buf->minor = minor;
309                 buf->icanon = tty->icanon;
310         }
311         do {
312                 size_t run;
313
314                 run = N_TTY_BUF_SIZE - buf->valid;
315                 if (run > size)
316                         run = size;
317                 memcpy(buf->data + buf->valid, data, run);
318                 buf->valid += run;
319                 data += run;
320                 size -= run;
321                 if (buf->valid == N_TTY_BUF_SIZE)
322                         tty_audit_buf_push_current(buf);
323         } while (size != 0);
324         mutex_unlock(&buf->mutex);
325         tty_audit_buf_put(buf);
326 }
327
328 /**
329  *      tty_audit_push  -       Push buffered data out
330  *
331  *      Make sure no audit data is pending for @tty on the current process.
332  */
333 void tty_audit_push(struct tty_struct *tty)
334 {
335         struct tty_audit_buf *buf;
336
337         spin_lock_irq(&current->sighand->siglock);
338         if (likely(!current->signal->audit_tty)) {
339                 spin_unlock_irq(&current->sighand->siglock);
340                 return;
341         }
342         buf = current->signal->tty_audit_buf;
343         if (buf)
344                 atomic_inc(&buf->count);
345         spin_unlock_irq(&current->sighand->siglock);
346
347         if (buf) {
348                 int major, minor;
349
350                 major = tty->driver->major;
351                 minor = tty->driver->minor_start + tty->index;
352                 mutex_lock(&buf->mutex);
353                 if (buf->major == major && buf->minor == minor)
354                         tty_audit_buf_push_current(buf);
355                 mutex_unlock(&buf->mutex);
356                 tty_audit_buf_put(buf);
357         }
358 }