media: video: fix clock settings for Tegra VI driver
[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                 buf->valid = 0;
100                 return;
101         }
102         tty_audit_log("tty", tsk, loginuid, sessionid, buf->major, buf->minor,
103                       buf->data, buf->valid);
104         buf->valid = 0;
105 }
106
107 /**
108  *      tty_audit_buf_push_current      -       Push buffered data out
109  *
110  *      Generate an audit message from the contents of @buf, which is owned by
111  *      the current task.  @buf->mutex must be locked.
112  */
113 static void tty_audit_buf_push_current(struct tty_audit_buf *buf)
114 {
115         uid_t auid = audit_get_loginuid(current);
116         unsigned int sessionid = audit_get_sessionid(current);
117         tty_audit_buf_push(current, auid, sessionid, buf);
118 }
119
120 /**
121  *      tty_audit_exit  -       Handle a task exit
122  *
123  *      Make sure all buffered data is written out and deallocate the buffer.
124  *      Only needs to be called if current->signal->tty_audit_buf != %NULL.
125  */
126 void tty_audit_exit(void)
127 {
128         struct tty_audit_buf *buf;
129
130         spin_lock_irq(&current->sighand->siglock);
131         buf = current->signal->tty_audit_buf;
132         current->signal->tty_audit_buf = NULL;
133         spin_unlock_irq(&current->sighand->siglock);
134         if (!buf)
135                 return;
136
137         mutex_lock(&buf->mutex);
138         tty_audit_buf_push_current(buf);
139         mutex_unlock(&buf->mutex);
140
141         tty_audit_buf_put(buf);
142 }
143
144 /**
145  *      tty_audit_fork  -       Copy TTY audit state for a new task
146  *
147  *      Set up TTY audit state in @sig from current.  @sig needs no locking.
148  */
149 void tty_audit_fork(struct signal_struct *sig)
150 {
151         spin_lock_irq(&current->sighand->siglock);
152         sig->audit_tty = current->signal->audit_tty;
153         spin_unlock_irq(&current->sighand->siglock);
154 }
155
156 /**
157  *      tty_audit_tiocsti       -       Log TIOCSTI
158  */
159 void tty_audit_tiocsti(struct tty_struct *tty, char ch)
160 {
161         struct tty_audit_buf *buf;
162         int major, minor, should_audit;
163
164         spin_lock_irq(&current->sighand->siglock);
165         should_audit = current->signal->audit_tty;
166         buf = current->signal->tty_audit_buf;
167         if (buf)
168                 atomic_inc(&buf->count);
169         spin_unlock_irq(&current->sighand->siglock);
170
171         major = tty->driver->major;
172         minor = tty->driver->minor_start + tty->index;
173         if (buf) {
174                 mutex_lock(&buf->mutex);
175                 if (buf->major == major && buf->minor == minor)
176                         tty_audit_buf_push_current(buf);
177                 mutex_unlock(&buf->mutex);
178                 tty_audit_buf_put(buf);
179         }
180
181         if (should_audit && audit_enabled) {
182                 uid_t auid;
183                 unsigned int sessionid;
184
185                 auid = audit_get_loginuid(current);
186                 sessionid = audit_get_sessionid(current);
187                 tty_audit_log("ioctl=TIOCSTI", current, auid, sessionid, major,
188                               minor, &ch, 1);
189         }
190 }
191
192 /**
193  * tty_audit_push_task  -       Flush task's pending audit data
194  * @tsk:                task pointer
195  * @loginuid:           sender login uid
196  * @sessionid:          sender session id
197  *
198  * Called with a ref on @tsk held. Try to lock sighand and get a
199  * reference to the tty audit buffer if available.
200  * Flush the buffer or return an appropriate error code.
201  */
202 int tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid)
203 {
204         struct tty_audit_buf *buf = ERR_PTR(-EPERM);
205         unsigned long flags;
206
207         if (!lock_task_sighand(tsk, &flags))
208                 return -ESRCH;
209
210         if (tsk->signal->audit_tty) {
211                 buf = tsk->signal->tty_audit_buf;
212                 if (buf)
213                         atomic_inc(&buf->count);
214         }
215         unlock_task_sighand(tsk, &flags);
216
217         /*
218          * Return 0 when signal->audit_tty set
219          * but tsk->signal->tty_audit_buf == NULL.
220          */
221         if (!buf || IS_ERR(buf))
222                 return PTR_ERR(buf);
223
224         mutex_lock(&buf->mutex);
225         tty_audit_buf_push(tsk, loginuid, sessionid, buf);
226         mutex_unlock(&buf->mutex);
227
228         tty_audit_buf_put(buf);
229         return 0;
230 }
231
232 /**
233  *      tty_audit_buf_get       -       Get an audit buffer.
234  *
235  *      Get an audit buffer for @tty, allocate it if necessary.  Return %NULL
236  *      if TTY auditing is disabled or out of memory.  Otherwise, return a new
237  *      reference to the buffer.
238  */
239 static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
240 {
241         struct tty_audit_buf *buf, *buf2;
242
243         buf = NULL;
244         buf2 = NULL;
245         spin_lock_irq(&current->sighand->siglock);
246         if (likely(!current->signal->audit_tty))
247                 goto out;
248         buf = current->signal->tty_audit_buf;
249         if (buf) {
250                 atomic_inc(&buf->count);
251                 goto out;
252         }
253         spin_unlock_irq(&current->sighand->siglock);
254
255         buf2 = tty_audit_buf_alloc(tty->driver->major,
256                                    tty->driver->minor_start + tty->index,
257                                    tty->icanon);
258         if (buf2 == NULL) {
259                 audit_log_lost("out of memory in TTY auditing");
260                 return NULL;
261         }
262
263         spin_lock_irq(&current->sighand->siglock);
264         if (!current->signal->audit_tty)
265                 goto out;
266         buf = current->signal->tty_audit_buf;
267         if (!buf) {
268                 current->signal->tty_audit_buf = buf2;
269                 buf = buf2;
270                 buf2 = NULL;
271         }
272         atomic_inc(&buf->count);
273         /* Fall through */
274  out:
275         spin_unlock_irq(&current->sighand->siglock);
276         if (buf2)
277                 tty_audit_buf_free(buf2);
278         return buf;
279 }
280
281 /**
282  *      tty_audit_add_data      -       Add data for TTY auditing.
283  *
284  *      Audit @data of @size from @tty, if necessary.
285  */
286 void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
287                         size_t size)
288 {
289         struct tty_audit_buf *buf;
290         int major, minor;
291
292         if (unlikely(size == 0))
293                 return;
294
295         if (tty->driver->type == TTY_DRIVER_TYPE_PTY
296             && tty->driver->subtype == PTY_TYPE_MASTER)
297                 return;
298
299         buf = tty_audit_buf_get(tty);
300         if (!buf)
301                 return;
302
303         mutex_lock(&buf->mutex);
304         major = tty->driver->major;
305         minor = tty->driver->minor_start + tty->index;
306         if (buf->major != major || buf->minor != minor
307             || buf->icanon != tty->icanon) {
308                 tty_audit_buf_push_current(buf);
309                 buf->major = major;
310                 buf->minor = minor;
311                 buf->icanon = tty->icanon;
312         }
313         do {
314                 size_t run;
315
316                 run = N_TTY_BUF_SIZE - buf->valid;
317                 if (run > size)
318                         run = size;
319                 memcpy(buf->data + buf->valid, data, run);
320                 buf->valid += run;
321                 data += run;
322                 size -= run;
323                 if (buf->valid == N_TTY_BUF_SIZE)
324                         tty_audit_buf_push_current(buf);
325         } while (size != 0);
326         mutex_unlock(&buf->mutex);
327         tty_audit_buf_put(buf);
328 }
329
330 /**
331  *      tty_audit_push  -       Push buffered data out
332  *
333  *      Make sure no audit data is pending for @tty on the current process.
334  */
335 void tty_audit_push(struct tty_struct *tty)
336 {
337         struct tty_audit_buf *buf;
338
339         spin_lock_irq(&current->sighand->siglock);
340         if (likely(!current->signal->audit_tty)) {
341                 spin_unlock_irq(&current->sighand->siglock);
342                 return;
343         }
344         buf = current->signal->tty_audit_buf;
345         if (buf)
346                 atomic_inc(&buf->count);
347         spin_unlock_irq(&current->sighand->siglock);
348
349         if (buf) {
350                 int major, minor;
351
352                 major = tty->driver->major;
353                 minor = tty->driver->minor_start + tty->index;
354                 mutex_lock(&buf->mutex);
355                 if (buf->major == major && buf->minor == minor)
356                         tty_audit_buf_push_current(buf);
357                 mutex_unlock(&buf->mutex);
358                 tty_audit_buf_put(buf);
359         }
360 }