1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * security/tomoyo/audit.c
4  *
5  * Copyright (C) 2005-2011  NTT DATA CORPORATION
6  */
7 
8 #include "common.h"
9 #include <linux/slab.h>
10 
11 /**
12  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
13  *
14  * @bprm: Pointer to "struct linux_binprm".
15  * @dump: Pointer to "struct tomoyo_page_dump".
16  *
17  * Returns the contents of @bprm on success, NULL otherwise.
18  *
19  * This function uses kzalloc(), so caller must kfree() if this function
20  * didn't return NULL.
21  */
tomoyo_print_bprm(struct linux_binprm * bprm,struct tomoyo_page_dump * dump)22 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
23 			       struct tomoyo_page_dump *dump)
24 {
25 	static const int tomoyo_buffer_len = 4096 * 2;
26 	char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
27 	char *cp;
28 	char *last_start;
29 	int len;
30 	unsigned long pos = bprm->p;
31 	int offset = pos % PAGE_SIZE;
32 	int argv_count = bprm->argc;
33 	int envp_count = bprm->envc;
34 	bool truncated = false;
35 
36 	if (!buffer)
37 		return NULL;
38 	len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
39 	cp = buffer + len;
40 	if (!argv_count) {
41 		memmove(cp, "} envp[]={ ", 11);
42 		cp += 11;
43 	}
44 	last_start = cp;
45 	while (argv_count || envp_count) {
46 		if (!tomoyo_dump_page(bprm, pos, dump))
47 			goto out;
48 		pos += PAGE_SIZE - offset;
49 		/* Read. */
50 		while (offset < PAGE_SIZE) {
51 			const char *kaddr = dump->data;
52 			const unsigned char c = kaddr[offset++];
53 
54 			if (cp == last_start)
55 				*cp++ = '"';
56 			if (cp >= buffer + tomoyo_buffer_len - 32) {
57 				/* Reserve some room for "..." string. */
58 				truncated = true;
59 			} else if (c == '\\') {
60 				*cp++ = '\\';
61 				*cp++ = '\\';
62 			} else if (c > ' ' && c < 127) {
63 				*cp++ = c;
64 			} else if (!c) {
65 				*cp++ = '"';
66 				*cp++ = ' ';
67 				last_start = cp;
68 			} else {
69 				*cp++ = '\\';
70 				*cp++ = (c >> 6) + '0';
71 				*cp++ = ((c >> 3) & 7) + '0';
72 				*cp++ = (c & 7) + '0';
73 			}
74 			if (c)
75 				continue;
76 			if (argv_count) {
77 				if (--argv_count == 0) {
78 					if (truncated) {
79 						cp = last_start;
80 						memmove(cp, "... ", 4);
81 						cp += 4;
82 					}
83 					memmove(cp, "} envp[]={ ", 11);
84 					cp += 11;
85 					last_start = cp;
86 					truncated = false;
87 				}
88 			} else if (envp_count) {
89 				if (--envp_count == 0) {
90 					if (truncated) {
91 						cp = last_start;
92 						memmove(cp, "... ", 4);
93 						cp += 4;
94 					}
95 				}
96 			}
97 			if (!argv_count && !envp_count)
98 				break;
99 		}
100 		offset = 0;
101 	}
102 	*cp++ = '}';
103 	*cp = '\0';
104 	return buffer;
105 out:
106 	snprintf(buffer, tomoyo_buffer_len - 1,
107 		 "argv[]={ ... } envp[]= { ... }");
108 	return buffer;
109 }
110 
111 /**
112  * tomoyo_filetype - Get string representation of file type.
113  *
114  * @mode: Mode value for stat().
115  *
116  * Returns file type string.
117  */
tomoyo_filetype(const umode_t mode)118 static inline const char *tomoyo_filetype(const umode_t mode)
119 {
120 	switch (mode & S_IFMT) {
121 	case S_IFREG:
122 	case 0:
123 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
124 	case S_IFDIR:
125 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
126 	case S_IFLNK:
127 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
128 	case S_IFIFO:
129 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
130 	case S_IFSOCK:
131 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
132 	case S_IFBLK:
133 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
134 	case S_IFCHR:
135 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
136 	}
137 	return "unknown"; /* This should not happen. */
138 }
139 
140 /**
141  * tomoyo_print_header - Get header line of audit log.
142  *
143  * @r: Pointer to "struct tomoyo_request_info".
144  *
145  * Returns string representation.
146  *
147  * This function uses kmalloc(), so caller must kfree() if this function
148  * didn't return NULL.
149  */
tomoyo_print_header(struct tomoyo_request_info * r)150 static char *tomoyo_print_header(struct tomoyo_request_info *r)
151 {
152 	struct tomoyo_time stamp;
153 	const pid_t gpid = task_pid_nr(current);
154 	struct tomoyo_obj_info *obj = r->obj;
155 	static const int tomoyo_buffer_len = 4096;
156 	char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
157 	int pos;
158 	u8 i;
159 
160 	if (!buffer)
161 		return NULL;
162 
163 	tomoyo_convert_time(ktime_get_real_seconds(), &stamp);
164 
165 	pos = snprintf(buffer, tomoyo_buffer_len - 1,
166 		       "#%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 }",
167 		       stamp.year, stamp.month, stamp.day, stamp.hour,
168 		       stamp.min, stamp.sec, r->profile, tomoyo_mode[r->mode],
169 		       tomoyo_yesno(r->granted), gpid, tomoyo_sys_getpid(),
170 		       tomoyo_sys_getppid(),
171 		       from_kuid(&init_user_ns, current_uid()),
172 		       from_kgid(&init_user_ns, current_gid()),
173 		       from_kuid(&init_user_ns, current_euid()),
174 		       from_kgid(&init_user_ns, current_egid()),
175 		       from_kuid(&init_user_ns, current_suid()),
176 		       from_kgid(&init_user_ns, current_sgid()),
177 		       from_kuid(&init_user_ns, current_fsuid()),
178 		       from_kgid(&init_user_ns, current_fsgid()));
179 	if (!obj)
180 		goto no_obj_info;
181 	if (!obj->validate_done) {
182 		tomoyo_get_attributes(obj);
183 		obj->validate_done = true;
184 	}
185 	for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
186 		struct tomoyo_mini_stat *stat;
187 		unsigned int dev;
188 		umode_t mode;
189 
190 		if (!obj->stat_valid[i])
191 			continue;
192 		stat = &obj->stat[i];
193 		dev = stat->dev;
194 		mode = stat->mode;
195 		if (i & 1) {
196 			pos += snprintf(buffer + pos,
197 					tomoyo_buffer_len - 1 - pos,
198 					" path%u.parent={ uid=%u gid=%u ino=%lu perm=0%o }",
199 					(i >> 1) + 1,
200 					from_kuid(&init_user_ns, stat->uid),
201 					from_kgid(&init_user_ns, stat->gid),
202 					(unsigned long)stat->ino,
203 					stat->mode & S_IALLUGO);
204 			continue;
205 		}
206 		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
207 				" path%u={ uid=%u gid=%u ino=%lu major=%u minor=%u perm=0%o type=%s",
208 				(i >> 1) + 1,
209 				from_kuid(&init_user_ns, stat->uid),
210 				from_kgid(&init_user_ns, stat->gid),
211 				(unsigned long)stat->ino,
212 				MAJOR(dev), MINOR(dev),
213 				mode & S_IALLUGO, tomoyo_filetype(mode));
214 		if (S_ISCHR(mode) || S_ISBLK(mode)) {
215 			dev = stat->rdev;
216 			pos += snprintf(buffer + pos,
217 					tomoyo_buffer_len - 1 - pos,
218 					" dev_major=%u dev_minor=%u",
219 					MAJOR(dev), MINOR(dev));
220 		}
221 		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
222 				" }");
223 	}
224 no_obj_info:
225 	if (pos < tomoyo_buffer_len - 1)
226 		return buffer;
227 	kfree(buffer);
228 	return NULL;
229 }
230 
231 /**
232  * tomoyo_init_log - Allocate buffer for audit logs.
233  *
234  * @r:    Pointer to "struct tomoyo_request_info".
235  * @len:  Buffer size needed for @fmt and @args.
236  * @fmt:  The printf()'s format string.
237  * @args: va_list structure for @fmt.
238  *
239  * Returns pointer to allocated memory.
240  *
241  * This function uses kzalloc(), so caller must kfree() if this function
242  * didn't return NULL.
243  */
tomoyo_init_log(struct tomoyo_request_info * r,int len,const char * fmt,va_list args)244 char *tomoyo_init_log(struct tomoyo_request_info *r, int len, const char *fmt,
245 		      va_list args)
246 {
247 	char *buf = NULL;
248 	char *bprm_info = NULL;
249 	const char *header = NULL;
250 	char *realpath = NULL;
251 	const char *symlink = NULL;
252 	int pos;
253 	const char *domainname = r->domain->domainname->name;
254 
255 	header = tomoyo_print_header(r);
256 	if (!header)
257 		return NULL;
258 	/* +10 is for '\n' etc. and '\0'. */
259 	len += strlen(domainname) + strlen(header) + 10;
260 	if (r->ee) {
261 		struct file *file = r->ee->bprm->file;
262 
263 		realpath = tomoyo_realpath_from_path(&file->f_path);
264 		bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
265 		if (!realpath || !bprm_info)
266 			goto out;
267 		/* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
268 		len += strlen(realpath) + 80 + strlen(bprm_info);
269 	} else if (r->obj && r->obj->symlink_target) {
270 		symlink = r->obj->symlink_target->name;
271 		/* +18 is for " symlink.target=\"%s\"" */
272 		len += 18 + strlen(symlink);
273 	}
274 	len = tomoyo_round2(len);
275 	buf = kzalloc(len, GFP_NOFS);
276 	if (!buf)
277 		goto out;
278 	len--;
279 	pos = snprintf(buf, len, "%s", header);
280 	if (realpath) {
281 		struct linux_binprm *bprm = r->ee->bprm;
282 
283 		pos += snprintf(buf + pos, len - pos,
284 				" exec={ realpath=\"%s\" argc=%d envc=%d %s }",
285 				realpath, bprm->argc, bprm->envc, bprm_info);
286 	} else if (symlink)
287 		pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
288 				symlink);
289 	pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
290 	vsnprintf(buf + pos, len - pos, fmt, args);
291 out:
292 	kfree(realpath);
293 	kfree(bprm_info);
294 	kfree(header);
295 	return buf;
296 }
297 
298 /* Wait queue for /sys/kernel/security/tomoyo/audit. */
299 static DECLARE_WAIT_QUEUE_HEAD(tomoyo_log_wait);
300 
301 /* Structure for audit log. */
302 struct tomoyo_log {
303 	struct list_head list;
304 	char *log;
305 	int size;
306 };
307 
308 /* The list for "struct tomoyo_log". */
309 static LIST_HEAD(tomoyo_log);
310 
311 /* Lock for "struct list_head tomoyo_log". */
312 static DEFINE_SPINLOCK(tomoyo_log_lock);
313 
314 /* Length of "struct list_head tomoyo_log". */
315 static unsigned int tomoyo_log_count;
316 
317 /**
318  * tomoyo_get_audit - Get audit mode.
319  *
320  * @ns:          Pointer to "struct tomoyo_policy_namespace".
321  * @profile:     Profile number.
322  * @index:       Index number of functionality.
323  * @matched_acl: Pointer to "struct tomoyo_acl_info".
324  * @is_granted:  True if granted log, false otherwise.
325  *
326  * Returns true if this request should be audited, false otherwise.
327  */
tomoyo_get_audit(const struct tomoyo_policy_namespace * ns,const u8 profile,const u8 index,const struct tomoyo_acl_info * matched_acl,const bool is_granted)328 static bool tomoyo_get_audit(const struct tomoyo_policy_namespace *ns,
329 			     const u8 profile, const u8 index,
330 			     const struct tomoyo_acl_info *matched_acl,
331 			     const bool is_granted)
332 {
333 	u8 mode;
334 	const u8 category = tomoyo_index2category[index] +
335 		TOMOYO_MAX_MAC_INDEX;
336 	struct tomoyo_profile *p;
337 
338 	if (!tomoyo_policy_loaded)
339 		return false;
340 	p = tomoyo_profile(ns, profile);
341 	if (tomoyo_log_count >= p->pref[TOMOYO_PREF_MAX_AUDIT_LOG])
342 		return false;
343 	if (is_granted && matched_acl && matched_acl->cond &&
344 	    matched_acl->cond->grant_log != TOMOYO_GRANTLOG_AUTO)
345 		return matched_acl->cond->grant_log == TOMOYO_GRANTLOG_YES;
346 	mode = p->config[index];
347 	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
348 		mode = p->config[category];
349 	if (mode == TOMOYO_CONFIG_USE_DEFAULT)
350 		mode = p->default_config;
351 	if (is_granted)
352 		return mode & TOMOYO_CONFIG_WANT_GRANT_LOG;
353 	return mode & TOMOYO_CONFIG_WANT_REJECT_LOG;
354 }
355 
356 /**
357  * tomoyo_write_log2 - Write an audit log.
358  *
359  * @r:    Pointer to "struct tomoyo_request_info".
360  * @len:  Buffer size needed for @fmt and @args.
361  * @fmt:  The printf()'s format string.
362  * @args: va_list structure for @fmt.
363  *
364  * Returns nothing.
365  */
tomoyo_write_log2(struct tomoyo_request_info * r,int len,const char * fmt,va_list args)366 void tomoyo_write_log2(struct tomoyo_request_info *r, int len, const char *fmt,
367 		       va_list args)
368 {
369 	char *buf;
370 	struct tomoyo_log *entry;
371 	bool quota_exceeded = false;
372 
373 	if (!tomoyo_get_audit(r->domain->ns, r->profile, r->type,
374 			      r->matched_acl, r->granted))
375 		goto out;
376 	buf = tomoyo_init_log(r, len, fmt, args);
377 	if (!buf)
378 		goto out;
379 	entry = kzalloc(sizeof(*entry), GFP_NOFS);
380 	if (!entry) {
381 		kfree(buf);
382 		goto out;
383 	}
384 	entry->log = buf;
385 	len = tomoyo_round2(strlen(buf) + 1);
386 	/*
387 	 * The entry->size is used for memory quota checks.
388 	 * Don't go beyond strlen(entry->log).
389 	 */
390 	entry->size = len + tomoyo_round2(sizeof(*entry));
391 	spin_lock(&tomoyo_log_lock);
392 	if (tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT] &&
393 	    tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] + entry->size >=
394 	    tomoyo_memory_quota[TOMOYO_MEMORY_AUDIT]) {
395 		quota_exceeded = true;
396 	} else {
397 		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] += entry->size;
398 		list_add_tail(&entry->list, &tomoyo_log);
399 		tomoyo_log_count++;
400 	}
401 	spin_unlock(&tomoyo_log_lock);
402 	if (quota_exceeded) {
403 		kfree(buf);
404 		kfree(entry);
405 		goto out;
406 	}
407 	wake_up(&tomoyo_log_wait);
408 out:
409 	return;
410 }
411 
412 /**
413  * tomoyo_write_log - Write an audit log.
414  *
415  * @r:   Pointer to "struct tomoyo_request_info".
416  * @fmt: The printf()'s format string, followed by parameters.
417  *
418  * Returns nothing.
419  */
tomoyo_write_log(struct tomoyo_request_info * r,const char * fmt,...)420 void tomoyo_write_log(struct tomoyo_request_info *r, const char *fmt, ...)
421 {
422 	va_list args;
423 	int len;
424 
425 	va_start(args, fmt);
426 	len = vsnprintf((char *) &len, 1, fmt, args) + 1;
427 	va_end(args);
428 	va_start(args, fmt);
429 	tomoyo_write_log2(r, len, fmt, args);
430 	va_end(args);
431 }
432 
433 /**
434  * tomoyo_read_log - Read an audit log.
435  *
436  * @head: Pointer to "struct tomoyo_io_buffer".
437  *
438  * Returns nothing.
439  */
tomoyo_read_log(struct tomoyo_io_buffer * head)440 void tomoyo_read_log(struct tomoyo_io_buffer *head)
441 {
442 	struct tomoyo_log *ptr = NULL;
443 
444 	if (head->r.w_pos)
445 		return;
446 	kfree(head->read_buf);
447 	head->read_buf = NULL;
448 	spin_lock(&tomoyo_log_lock);
449 	if (!list_empty(&tomoyo_log)) {
450 		ptr = list_entry(tomoyo_log.next, typeof(*ptr), list);
451 		list_del(&ptr->list);
452 		tomoyo_log_count--;
453 		tomoyo_memory_used[TOMOYO_MEMORY_AUDIT] -= ptr->size;
454 	}
455 	spin_unlock(&tomoyo_log_lock);
456 	if (ptr) {
457 		head->read_buf = ptr->log;
458 		head->r.w[head->r.w_pos++] = head->read_buf;
459 		kfree(ptr);
460 	}
461 }
462 
463 /**
464  * tomoyo_poll_log - Wait for an audit log.
465  *
466  * @file: Pointer to "struct file".
467  * @wait: Pointer to "poll_table". Maybe NULL.
468  *
469  * Returns EPOLLIN | EPOLLRDNORM when ready to read an audit log.
470  */
tomoyo_poll_log(struct file * file,poll_table * wait)471 __poll_t tomoyo_poll_log(struct file *file, poll_table *wait)
472 {
473 	if (tomoyo_log_count)
474 		return EPOLLIN | EPOLLRDNORM;
475 	poll_wait(file, &tomoyo_log_wait, wait);
476 	if (tomoyo_log_count)
477 		return EPOLLIN | EPOLLRDNORM;
478 	return 0;
479 }
480