1/*
2 * security/tomoyo/audit.c
3 *
4 * Copyright (C) 2005-2011  NTT DATA CORPORATION
5 */
6
7#include "common.h"
8#include <linux/slab.h>
9
10/**
11 * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
12 *
13 * @bprm: Pointer to "struct linux_binprm".
14 * @dump: Pointer to "struct tomoyo_page_dump".
15 *
16 * Returns the contents of @bprm on success, NULL otherwise.
17 *
18 * This function uses kzalloc(), so caller must kfree() if this function
19 * didn't return NULL.
20 */
21static char *tomoyo_print_bprm(struct linux_binprm *bprm,
22			       struct tomoyo_page_dump *dump)
23{
24	static const int tomoyo_buffer_len = 4096 * 2;
25	char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
26	char *cp;
27	char *last_start;
28	int len;
29	unsigned long pos = bprm->p;
30	int offset = pos % PAGE_SIZE;
31	int argv_count = bprm->argc;
32	int envp_count = bprm->envc;
33	bool truncated = false;
34	if (!buffer)
35		return NULL;
36	len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
37	cp = buffer + len;
38	if (!argv_count) {
39		memmove(cp, "} envp[]={ ", 11);
40		cp += 11;
41	}
42	last_start = cp;
43	while (argv_count || envp_count) {
44		if (!tomoyo_dump_page(bprm, pos, dump))
45			goto out;
46		pos += PAGE_SIZE - offset;
47		/* Read. */
48		while (offset < PAGE_SIZE) {
49			const char *kaddr = dump->data;
50			const unsigned char c = kaddr[offset++];
51			if (cp == last_start)
52				*cp++ = '"';
53			if (cp >= buffer + tomoyo_buffer_len - 32) {
54				/* Reserve some room for "..." string. */
55				truncated = true;
56			} else if (c == '\\') {
57				*cp++ = '\\';
58				*cp++ = '\\';
59			} else if (c > ' ' && c < 127) {
60				*cp++ = c;
61			} else if (!c) {
62				*cp++ = '"';
63				*cp++ = ' ';
64				last_start = cp;
65			} else {
66				*cp++ = '\\';
67				*cp++ = (c >> 6) + '0';
68				*cp++ = ((c >> 3) & 7) + '0';
69				*cp++ = (c & 7) + '0';
70			}
71			if (c)
72				continue;
73			if (argv_count) {
74				if (--argv_count == 0) {
75					if (truncated) {
76						cp = last_start;
77						memmove(cp, "... ", 4);
78						cp += 4;
79					}
80					memmove(cp, "} envp[]={ ", 11);
81					cp += 11;
82					last_start = cp;
83					truncated = false;
84				}
85			} else if (envp_count) {
86				if (--envp_count == 0) {
87					if (truncated) {
88						cp = last_start;
89						memmove(cp, "... ", 4);
90						cp += 4;
91					}
92				}
93			}
94			if (!argv_count && !envp_count)
95				break;
96		}
97		offset = 0;
98	}
99	*cp++ = '}';
100	*cp = '\0';
101	return buffer;
102out:
103	snprintf(buffer, tomoyo_buffer_len - 1,
104		 "argv[]={ ... } envp[]= { ... }");
105	return buffer;
106}
107
108/**
109 * tomoyo_filetype - Get string representation of file type.
110 *
111 * @mode: Mode value for stat().
112 *
113 * Returns file type string.
114 */
115static inline const char *tomoyo_filetype(const umode_t mode)
116{
117	switch (mode & S_IFMT) {
118	case S_IFREG:
119	case 0:
120		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
121	case S_IFDIR:
122		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
123	case S_IFLNK:
124		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
125	case S_IFIFO:
126		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
127	case S_IFSOCK:
128		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
129	case S_IFBLK:
130		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
131	case S_IFCHR:
132		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
133	}
134	return "unknown"; /* This should not happen. */
135}
136
137/**
138 * tomoyo_print_header - Get header line of audit log.
139 *
140 * @r: Pointer to "struct tomoyo_request_info".
141 *
142 * Returns string representation.
143 *
144 * This function uses kmalloc(), so caller must kfree() if this function
145 * didn't return NULL.
146 */
147static char *tomoyo_print_header(struct tomoyo_request_info *r)
148{
149	struct tomoyo_time stamp;
150	const pid_t gpid = task_pid_nr(current);
151	struct tomoyo_obj_info *obj = r->obj;
152	static const int tomoyo_buffer_len = 4096;
153	char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
154	int pos;
155	u8 i;
156	if (!buffer)
157		return NULL;
158
159	tomoyo_convert_time(get_seconds(), &stamp);
160
161	pos = snprintf(buffer, tomoyo_buffer_len - 1,
162		       "#%04u/%02u/%02u %02u:%02u:%02u# profile=%u mode=%s "
163		       "granted=%s (global-pid=%u) task={ pid=%u ppid=%u "
164		       "uid=%u gid=%u euid=%u egid=%u suid=%u sgid=%u "
165		       "fsuid=%u fsgid=%u }", stamp.year, stamp.month,
166		       stamp.day, stamp.hour, stamp.min, stamp.sec, r->profile,
167		       tomoyo_mode[r->mode], tomoyo_yesno(r->granted), gpid,
168		       tomoyo_sys_getpid(), tomoyo_sys_getppid(),
169		       from_kuid(&init_user_ns, current_uid()),
170		       from_kgid(&init_user_ns, current_gid()),
171		       from_kuid(&init_user_ns, current_euid()),
172		       from_kgid(&init_user_ns, current_egid()),
173		       from_kuid(&init_user_ns, current_suid()),
174		       from_kgid(&init_user_ns, current_sgid()),
175		       from_kuid(&init_user_ns, current_fsuid()),
176		       from_kgid(&init_user_ns, current_fsgid()));
177	if (!obj)
178		goto no_obj_info;
179	if (!obj->validate_done) {
180		tomoyo_get_attributes(obj);
181		obj->validate_done = true;
182	}
183	for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
184		struct tomoyo_mini_stat *stat;
185		unsigned int dev;
186		umode_t mode;
187		if (!obj->stat_valid[i])
188			continue;
189		stat = &obj->stat[i];
190		dev = stat->dev;
191		mode = stat->mode;
192		if (i & 1) {
193			pos += snprintf(buffer + pos,
194					tomoyo_buffer_len - 1 - pos,
195					" path%u.parent={ uid=%u gid=%u "
196					"ino=%lu perm=0%o }", (i >> 1) + 1,
197					from_kuid(&init_user_ns, stat->uid),
198					from_kgid(&init_user_ns, stat->gid),
199					(unsigned long)stat->ino,
200					stat->mode & S_IALLUGO);
201			continue;
202		}
203		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
204				" path%u={ uid=%u gid=%u ino=%lu major=%u"
205				" minor=%u perm=0%o type=%s", (i >> 1) + 1,
206				from_kuid(&init_user_ns, stat->uid),
207				from_kgid(&init_user_ns, stat->gid),
208				(unsigned long)stat->ino,
209				MAJOR(dev), MINOR(dev),
210				mode & S_IALLUGO, tomoyo_filetype(mode));
211		if (S_ISCHR(mode) || S_ISBLK(mode)) {
212			dev = stat->rdev;
213			pos += snprintf(buffer + pos,
214					tomoyo_buffer_len - 1 - pos,
215					" dev_major=%u dev_minor=%u",
216					MAJOR(dev), MINOR(dev));
217		}
218		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
219				" }");
220	}
221no_obj_info:
222	if (pos < tomoyo_buffer_len - 1)
223		return buffer;
224	kfree(buffer);
225	return NULL;
226}
227
228/**
229 * tomoyo_init_log - Allocate buffer for audit logs.
230 *
231 * @r:    Pointer to "struct tomoyo_request_info".
232 * @len:  Buffer size needed for @fmt and @args.
233 * @fmt:  The printf()'s format string.
234 * @args: va_list structure for @fmt.
235 *
236 * Returns pointer to allocated memory.
237 *
238 * This function uses kzalloc(), so caller must kfree() if this function
239 * didn't return NULL.
240 */
241char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
242		      va_list args)
243{
244	char *buf = NULL;
245	char *bprm_info = NULL;
246	const char *header = NULL;
247	char *realpath = NULL;
248	const char *symlink = NULL;
249	int pos;
250	const char *domainname = r->domain->domainname->name;
251	header = tomoyo_print_header(r);
252	if (!header)
253		return NULL;
254	/* +10 is for '\n' etc. and '\0'. */
255	len += strlen(domainname) + strlen(header) + 10;
256	if (r->ee) {
257		struct file *file = r->ee->bprm->file;
258		realpath = tomoyo_realpath_from_path(&file->f_path);
259		bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
260		if (!realpath || !bprm_info)
261			goto out;
262		/* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
263		len += strlen(realpath) + 80 + strlen(bprm_info);
264	} else if (r->obj && r->obj->symlink_target) {
265		symlink = r->obj->symlink_target->name;
266		/* +18 is for " symlink.target=\"%s\"" */
267		len += 18 + strlen(symlink);
268	}
269	len = tomoyo_round2(len);
270	buf = kzalloc(len, GFP_NOFS);
271	if (!buf)
272		goto out;
273	len--;
274	pos = snprintf(buf, len, "%s", header);
275	if (realpath) {
276		struct linux_binprm *bprm = r->ee->bprm;
277		pos += snprintf(buf + pos, len - pos,
278				" exec={ realpath=\"%s\" argc=%d envc=%d %s }",
279				realpath, bprm->argc, bprm->envc, bprm_info);
280	} else if (symlink)
281		pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
282				symlink);
283	pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
284	vsnprintf(buf + pos, len - pos, fmt, args);
285out:
286	kfree(realpath);
287	kfree(bprm_info);
288	kfree(header);
289	return buf;
290}
291
292/* Wait queue for /sys/kernel/security/tomoyo/audit. */
293static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
294
295/* Structure for audit log. */
296struct tomoyo_log {
297	struct list_head list;
298	char *log;
299	int size;
300};
301
302/* The list for "struct tomoyo_log". */
303static LIST_HEAD(tomoyo_log);
304
305/* Lock for "struct list_head tomoyo_log". */
306static DEFINE_SPINLOCK(tomoyo_log_lock);
307
308/* Length of "stuct list_head tomoyo_log". */
309static unsigned int tomoyo_log_count;
310
311/**
312 * tomoyo_get_audit - Get audit mode.
313 *
314 * @ns:          Pointer to "struct tomoyo_policy_namespace".
315 * @profile:     Profile number.
316 * @index:       Index number of functionality.
317 * @is_granted:  True if granted log, false otherwise.
318 *
319 * Returns true if this request should be audited, false otherwise.
320 */
321static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
322			     const u8 profile, const u8 index,
323			     const struct tomoyo_acl_info *matched_acl,
324			     const bool is_granted)
325{
326	u8 mode;
327	const u8 category = tomoyo_index2category[index] +
328		TOMOYO_MAX_MAC_INDEX;
329	struct tomoyo_profile *p;
330	if (!tomoyo_policy_loaded)
331		return false;
332	p = tomoyo_profile(ns, profile);
333	if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
334		return false;
335	if (is_granted && matched_acl && matched_acl->cond &&
336	    matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
337		return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
338	mode = p->config[index];
339	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
340		mode = p->config[category];
341	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
342		mode = p->default_config;
343	if (is_granted)
344		return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
345	return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
346}
347
348/**
349 * tomoyo_write_log2 - Write an audit log.
350 *
351 * @r:    Pointer to "struct tomoyo_request_info".
352 * @len:  Buffer size needed for @fmt and @args.
353 * @fmt:  The printf()'s format string.
354 * @args: va_list structure for @fmt.
355 *
356 * Returns nothing.
357 */
358void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
359		       va_list args)
360{
361	char *buf;
362	struct tomoyo_log *entry;
363	bool quota_exceeded = false;
364	if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
365			      r->matched_acl, r->granted))
366		goto out;
367	buf = tomoyo_init_log(r, len, fmt, args);
368	if (!buf)
369		goto out;
370	entry = kzalloc(sizeof(*entry), GFP_NOFS);
371	if (!entry) {
372		kfree(buf);
373		goto out;
374	}
375	entry->log = buf;
376	len = tomoyo_round2(strlen(buf) + 1);
377	/*
378	 * The entry->size is used for memory quota checks.
379	 * Don't go beyond strlen(entry->log).
380	 */
381	entry->size = len + tomoyo_round2(sizeof(*entry));
382	spin_lock(&tomoyo_log_lock);
383	if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
384	    tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
385	    tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
386		quota_exceeded = true;
387	} else {
388		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
389		list_add_tail(&entry->list, &tomoyo_log);
390		tomoyo_log_count++;
391	}
392	spin_unlock(&tomoyo_log_lock);
393	if (quota_exceeded) {
394		kfree(buf);
395		kfree(entry);
396		goto out;
397	}
398	wake_up(&tomoyo_log_wait);
399out:
400	return;
401}
402
403/**
404 * tomoyo_write_log - Write an audit log.
405 *
406 * @r:   Pointer to "struct tomoyo_request_info".
407 * @fmt: The printf()'s format string, followed by parameters.
408 *
409 * Returns nothing.
410 */
411void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
412{
413	va_list args;
414	int len;
415	va_start(args, fmt);
416	len = vsnprintf((char *) &len, 1, fmt, args) + 1;
417	va_end(args);
418	va_start(args, fmt);
419	tomoyo_write_log2(r, len, fmt, args);
420	va_end(args);
421}
422
423/**
424 * tomoyo_read_log - Read an audit log.
425 *
426 * @head: Pointer to "struct tomoyo_io_buffer".
427 *
428 * Returns nothing.
429 */
430void tomoyo_read_log(struct tomoyo_io_buffer *head)
431{
432	struct tomoyo_log *ptr = NULL;
433	if (head->r.w_pos)
434		return;
435	kfree(head->read_buf);
436	head->read_buf = NULL;
437	spin_lock(&tomoyo_log_lock);
438	if (!list_empty(&tomoyo_log)) {
439		ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
440		list_del(&ptr->list);
441		tomoyo_log_count--;
442		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
443	}
444	spin_unlock(&tomoyo_log_lock);
445	if (ptr) {
446		head->read_buf = ptr->log;
447		head->r.w[head->r.w_pos++] = head->read_buf;
448		kfree(ptr);
449	}
450}
451
452/**
453 * tomoyo_poll_log - Wait for an audit log.
454 *
455 * @file: Pointer to "struct file".
456 * @wait: Pointer to "poll_table". Maybe NULL.
457 *
458 * Returns POLLIN | POLLRDNORM when ready to read an audit log.
459 */
460unsigned int tomoyo_poll_log(struct file *file, poll_table *wait)
461{
462	if (tomoyo_log_count)
463		return POLLIN | POLLRDNORM;
464	poll_wait(file, &tomoyo_log_wait, wait);
465	if (tomoyo_log_count)
466		return POLLIN | POLLRDNORM;
467	return 0;
468}
469