audit.c 7.43 KB
Newer Older
Tetsuo Handa's avatar
Tetsuo Handa committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
/*
 * security/tomoyo/audit.c
 *
 * Pathname restriction functions.
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 */

#include "common.h"
#include <linux/slab.h>

/**
 * tomoyo_convert_time - Convert time_t to YYYY/MM/DD hh/mm/ss.
 *
 * @time:  Seconds since 1970/01/01 00:00:00.
 * @stamp: Pointer to "struct tomoyo_time".
 *
 * Returns nothing.
 *
 * This function does not handle Y2038 problem.
 */
static void tomoyo_convert_time(time_t time, struct tomoyo_time *stamp)
{
	static const u16 tomoyo_eom[2][12] = {
		{ 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
		{ 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
	};
	u16 y;
	u8 m;
	bool r;
	stamp->sec = time % 60;
	time /= 60;
	stamp->min = time % 60;
	time /= 60;
	stamp->hour = time % 24;
	time /= 24;
	for (y = 1970; ; y++) {
		const unsigned short days = (y & 3) ? 365 : 366;
		if (time < days)
			break;
		time -= days;
	}
	r = (y & 3) == 0;
	for (m = 0; m < 11 && time >= tomoyo_eom[r][m]; m++)
		;
	if (m)
		time -= tomoyo_eom[r][m - 1];
	stamp->year = y;
	stamp->month = ++m;
	stamp->day = ++time;
}

/**
 * tomoyo_print_header - Get header line of audit log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns string representation.
 *
 * This function uses kmalloc(), so caller must kfree() if this function
 * didn't return NULL.
 */
static char *tomoyo_print_header(struct tomoyo_request_info *r)
{
	struct tomoyo_time stamp;
	const pid_t gpid = task_pid_nr(current);
	static const int tomoyo_buffer_len = 4096;
	char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
	pid_t ppid;
	if (!buffer)
		return NULL;
	{
		struct timeval tv;
		do_gettimeofday(&tv);
		tomoyo_convert_time(tv.tv_sec, &stamp);
	}
	rcu_read_lock();
	ppid = task_tgid_vnr(current->real_parent);
	rcu_read_unlock();
	snprintf(buffer, tomoyo_buffer_len - 1,
		 "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
		 "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
		 "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
		 "fsuid=%u fsgid=%u }",
		 stamp.year, stamp.month, stamp.day, stamp.hour,
		 stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
		 tomoyo_yesno(r->granted), gpid, task_tgid_vnr(current), ppid,
		 current_uid(), current_gid(), current_euid(), current_egid(),
		 current_suid(), current_sgid(), current_fsuid(),
		 current_fsgid());
	return buffer;
}

/**
 * tomoyo_init_log - Allocate buffer for audit logs.
 *
 * @r:    Pointer to "struct tomoyo_request_info".
 * @len:  Buffer size needed for @fmt and @args.
 * @fmt:  The printf()'s format string.
 * @args: va_list structure for @fmt.
 *
 * Returns pointer to allocated memory.
 *
 * This function uses kzalloc(), so caller must kfree() if this function
 * didn't return NULL.
 */
char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
		      va_list args)
{
	char *buf = NULL;
	const char *header = NULL;
	int pos;
	const char *domainname = tomoyo_domain()->domainname->name;
	header = tomoyo_print_header(r);
	if (!header)
		return NULL;
	/* +10 is for '\n' etc. and '\0'. */
	len += strlen(domainname) + strlen(header) + 10;
	len = tomoyo_round2(len);
	buf = kzalloc(len, GFP_NOFS);
	if (!buf)
		goto out;
	len--;
	pos = snprintf(buf, len, "%s", header);
	pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
	vsnprintf(buf + pos, len - pos, fmt, args);
out:
	kfree(header);
	return buf;
}

/* Wait queue for /sys/kernel/security/tomoyo/audit. */
static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);

/* Structure for audit log. */
struct tomoyo_log {
	struct list_head list;
	char *log;
	int size;
};

/* The list for "struct tomoyo_log". */
static LIST_HEAD(tomoyo_log);

/* Lock for "struct list_head tomoyo_log". */
static DEFINE_SPINLOCK(tomoyo_log_lock);

/* Length of "stuct list_head tomoyo_log". */
static unsigned int tomoyo_log_count;

/**
 * tomoyo_get_audit - Get audit mode.
 *
 * @profile:     Profile number.
 * @index:       Index number of functionality.
 * @is_granted:  True if granted log, false otherwise.
 *
 * Returns true if this request should be audited, false otherwise.
 */
static bool tomoyo_get_audit(const u8 profile, const u8 index,
			     const bool is_granted)
{
	u8 mode;
	const u8 category = TOMOYO_MAC_CATEGORY_FILE + TOMOYO_MAX_MAC_INDEX;
	struct tomoyo_profile *p;
	if (!tomoyo_policy_loaded)
		return false;
	p = tomoyo_profile(profile);
	if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
		return false;
	mode = p->config[index];
	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
		mode = p->config[category];
	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
		mode = p->default_config;
	if (is_granted)
		return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
	return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
}

/**
 * tomoyo_write_log2 - Write an audit log.
 *
 * @r:    Pointer to "struct tomoyo_request_info".
 * @len:  Buffer size needed for @fmt and @args.
 * @fmt:  The printf()'s format string.
 * @args: va_list structure for @fmt.
 *
 * Returns nothing.
 */
void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
		       va_list args)
{
	char *buf;
	struct tomoyo_log *entry;
	bool quota_exceeded = false;
	if (!tomoyo_get_audit(r->profile, r->type, r->granted))
		goto out;
	buf = tomoyo_init_log(r, len, fmt, args);
	if (!buf)
		goto out;
	entry = kzalloc(sizeof(*entry), GFP_NOFS);
	if (!entry) {
		kfree(buf);
		goto out;
	}
	entry->log = buf;
	len = tomoyo_round2(strlen(buf) + 1);
	/*
	 * The entry->size is used for memory quota checks.
	 * Don't go beyond strlen(entry->log).
	 */
	entry->size = len + tomoyo_round2(sizeof(*entry));
	spin_lock(&tomoyo_log_lock);
	if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
	    tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
	    tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
		quota_exceeded = true;
	} else {
		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
		list_add_tail(&entry->list, &tomoyo_log);
		tomoyo_log_count++;
	}
	spin_unlock(&tomoyo_log_lock);
	if (quota_exceeded) {
		kfree(buf);
		kfree(entry);
		goto out;
	}
	wake_up(&tomoyo_log_wait);
out:
	return;
}

/**
 * tomoyo_write_log - Write an audit log.
 *
 * @r:   Pointer to "struct tomoyo_request_info".
 * @fmt: The printf()'s format string, followed by parameters.
 *
 * Returns nothing.
 */
void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
{
	va_list args;
	int len;
	va_start(args, fmt);
	len = vsnprintf((char *) &len, 1, fmt, args) + 1;
	va_end(args);
	va_start(args, fmt);
	tomoyo_write_log2(r, len, fmt, args);
	va_end(args);
}

/**
 * tomoyo_read_log - Read an audit log.
 *
 * @head: Pointer to "struct tomoyo_io_buffer".
 *
 * Returns nothing.
 */
void tomoyo_read_log(struct tomoyo_io_buffer *head)
{
	struct tomoyo_log *ptr = NULL;
	if (head->r.w_pos)
		return;
	kfree(head->read_buf);
	head->read_buf = NULL;
	spin_lock(&tomoyo_log_lock);
	if (!list_empty(&tomoyo_log)) {
		ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
		list_del(&ptr->list);
		tomoyo_log_count--;
		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
	}
	spin_unlock(&tomoyo_log_lock);
	if (ptr) {
		head->read_buf = ptr->log;
		head->r.w[head->r.w_pos++] = head->read_buf;
		kfree(ptr);
	}
}

/**
 * tomoyo_poll_log - Wait for an audit log.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Returns POLLIN | POLLRDNORM when ready to read an audit log.
 */
int tomoyo_poll_log(struct file *file, poll_table *wait)
{
	if (tomoyo_log_count)
		return POLLIN | POLLRDNORM;
	poll_wait(file, &tomoyo_log_wait, wait);
	if (tomoyo_log_count)
		return POLLIN | POLLRDNORM;
	return 0;
}