signals: use HAVE_SET_RESTORE_SIGMASK
[linux-2.6/mini2440.git] / drivers / char / tty_audit.c
blob6342b0534f4d3cda24aaac72cd5cb25deeb3021d
1 /*
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
7 * Public License v.2.
9 * Authors: Miloslav Trmac <mitr@redhat.com>
12 #include <linux/audit.h>
13 #include <linux/file.h>
14 #include <linux/tty.h>
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 */
25 static struct tty_audit_buf *tty_audit_buf_alloc(int major, int minor,
26 int icanon)
28 struct tty_audit_buf *buf;
30 buf = kmalloc(sizeof(*buf), GFP_KERNEL);
31 if (!buf)
32 goto err;
33 if (PAGE_SIZE != N_TTY_BUF_SIZE)
34 buf->data = kmalloc(N_TTY_BUF_SIZE, GFP_KERNEL);
35 else
36 buf->data = (unsigned char *)__get_free_page(GFP_KERNEL);
37 if (!buf->data)
38 goto err_buf;
39 atomic_set(&buf->count, 1);
40 mutex_init(&buf->mutex);
41 buf->major = major;
42 buf->minor = minor;
43 buf->icanon = icanon;
44 buf->valid = 0;
45 return buf;
47 err_buf:
48 kfree(buf);
49 err:
50 return NULL;
53 static void tty_audit_buf_free(struct tty_audit_buf *buf)
55 WARN_ON(buf->valid != 0);
56 if (PAGE_SIZE != N_TTY_BUF_SIZE)
57 kfree(buf->data);
58 else
59 free_page((unsigned long)buf->data);
60 kfree(buf);
63 static void tty_audit_buf_put(struct tty_audit_buf *buf)
65 if (atomic_dec_and_test(&buf->count))
66 tty_audit_buf_free(buf);
69 /**
70 * tty_audit_buf_push - Push buffered data out
72 * Generate an audit message from the contents of @buf, which is owned by
73 * @tsk with @loginuid. @buf->mutex must be locked.
75 static void tty_audit_buf_push(struct task_struct *tsk, uid_t loginuid,
76 unsigned int sessionid,
77 struct tty_audit_buf *buf)
79 struct audit_buffer *ab;
81 if (buf->valid == 0)
82 return;
83 if (audit_enabled == 0)
84 return;
85 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_TTY);
86 if (ab) {
87 char name[sizeof(tsk->comm)];
89 audit_log_format(ab, "tty pid=%u uid=%u auid=%u ses=%u "
90 "major=%d minor=%d comm=", tsk->pid, tsk->uid,
91 loginuid, sessionid, buf->major, buf->minor);
92 get_task_comm(name, tsk);
93 audit_log_untrustedstring(ab, name);
94 audit_log_format(ab, " data=");
95 audit_log_n_untrustedstring(ab, buf->data, buf->valid);
96 audit_log_end(ab);
98 buf->valid = 0;
102 * tty_audit_buf_push_current - Push buffered data out
104 * Generate an audit message from the contents of @buf, which is owned by
105 * the current task. @buf->mutex must be locked.
107 static void tty_audit_buf_push_current(struct tty_audit_buf *buf)
109 uid_t auid = audit_get_loginuid(current);
110 unsigned int sessionid = audit_get_sessionid(current);
111 tty_audit_buf_push(current, auid, sessionid, buf);
115 * tty_audit_exit - Handle a task exit
117 * Make sure all buffered data is written out and deallocate the buffer.
118 * Only needs to be called if current->signal->tty_audit_buf != %NULL.
120 void tty_audit_exit(void)
122 struct tty_audit_buf *buf;
124 spin_lock_irq(&current->sighand->siglock);
125 buf = current->signal->tty_audit_buf;
126 current->signal->tty_audit_buf = NULL;
127 spin_unlock_irq(&current->sighand->siglock);
128 if (!buf)
129 return;
131 mutex_lock(&buf->mutex);
132 tty_audit_buf_push_current(buf);
133 mutex_unlock(&buf->mutex);
135 tty_audit_buf_put(buf);
139 * tty_audit_fork - Copy TTY audit state for a new task
141 * Set up TTY audit state in @sig from current. @sig needs no locking.
143 void tty_audit_fork(struct signal_struct *sig)
145 spin_lock_irq(&current->sighand->siglock);
146 sig->audit_tty = current->signal->audit_tty;
147 spin_unlock_irq(&current->sighand->siglock);
148 sig->tty_audit_buf = NULL;
152 * tty_audit_push_task - Flush task's pending audit data
154 void tty_audit_push_task(struct task_struct *tsk, uid_t loginuid, u32 sessionid)
156 struct tty_audit_buf *buf;
158 spin_lock_irq(&tsk->sighand->siglock);
159 buf = tsk->signal->tty_audit_buf;
160 if (buf)
161 atomic_inc(&buf->count);
162 spin_unlock_irq(&tsk->sighand->siglock);
163 if (!buf)
164 return;
166 mutex_lock(&buf->mutex);
167 tty_audit_buf_push(tsk, loginuid, sessionid, buf);
168 mutex_unlock(&buf->mutex);
170 tty_audit_buf_put(buf);
174 * tty_audit_buf_get - Get an audit buffer.
176 * Get an audit buffer for @tty, allocate it if necessary. Return %NULL
177 * if TTY auditing is disabled or out of memory. Otherwise, return a new
178 * reference to the buffer.
180 static struct tty_audit_buf *tty_audit_buf_get(struct tty_struct *tty)
182 struct tty_audit_buf *buf, *buf2;
184 buf = NULL;
185 buf2 = NULL;
186 spin_lock_irq(&current->sighand->siglock);
187 if (likely(!current->signal->audit_tty))
188 goto out;
189 buf = current->signal->tty_audit_buf;
190 if (buf) {
191 atomic_inc(&buf->count);
192 goto out;
194 spin_unlock_irq(&current->sighand->siglock);
196 buf2 = tty_audit_buf_alloc(tty->driver->major,
197 tty->driver->minor_start + tty->index,
198 tty->icanon);
199 if (buf2 == NULL) {
200 audit_log_lost("out of memory in TTY auditing");
201 return NULL;
204 spin_lock_irq(&current->sighand->siglock);
205 if (!current->signal->audit_tty)
206 goto out;
207 buf = current->signal->tty_audit_buf;
208 if (!buf) {
209 current->signal->tty_audit_buf = buf2;
210 buf = buf2;
211 buf2 = NULL;
213 atomic_inc(&buf->count);
214 /* Fall through */
215 out:
216 spin_unlock_irq(&current->sighand->siglock);
217 if (buf2)
218 tty_audit_buf_free(buf2);
219 return buf;
223 * tty_audit_add_data - Add data for TTY auditing.
225 * Audit @data of @size from @tty, if necessary.
227 void tty_audit_add_data(struct tty_struct *tty, unsigned char *data,
228 size_t size)
230 struct tty_audit_buf *buf;
231 int major, minor;
233 if (unlikely(size == 0))
234 return;
236 if (tty->driver->type == TTY_DRIVER_TYPE_PTY
237 && tty->driver->subtype == PTY_TYPE_MASTER)
238 return;
240 buf = tty_audit_buf_get(tty);
241 if (!buf)
242 return;
244 mutex_lock(&buf->mutex);
245 major = tty->driver->major;
246 minor = tty->driver->minor_start + tty->index;
247 if (buf->major != major || buf->minor != minor
248 || buf->icanon != tty->icanon) {
249 tty_audit_buf_push_current(buf);
250 buf->major = major;
251 buf->minor = minor;
252 buf->icanon = tty->icanon;
254 do {
255 size_t run;
257 run = N_TTY_BUF_SIZE - buf->valid;
258 if (run > size)
259 run = size;
260 memcpy(buf->data + buf->valid, data, run);
261 buf->valid += run;
262 data += run;
263 size -= run;
264 if (buf->valid == N_TTY_BUF_SIZE)
265 tty_audit_buf_push_current(buf);
266 } while (size != 0);
267 mutex_unlock(&buf->mutex);
268 tty_audit_buf_put(buf);
272 * tty_audit_push - Push buffered data out
274 * Make sure no audit data is pending for @tty on the current process.
276 void tty_audit_push(struct tty_struct *tty)
278 struct tty_audit_buf *buf;
280 spin_lock_irq(&current->sighand->siglock);
281 if (likely(!current->signal->audit_tty)) {
282 spin_unlock_irq(&current->sighand->siglock);
283 return;
285 buf = current->signal->tty_audit_buf;
286 if (buf)
287 atomic_inc(&buf->count);
288 spin_unlock_irq(&current->sighand->siglock);
290 if (buf) {
291 int major, minor;
293 major = tty->driver->major;
294 minor = tty->driver->minor_start + tty->index;
295 mutex_lock(&buf->mutex);
296 if (buf->major == major && buf->minor == minor)
297 tty_audit_buf_push_current(buf);
298 mutex_unlock(&buf->mutex);
299 tty_audit_buf_put(buf);