security/tomoyo/audit.c - arm/linux - Git at Google

 /*
  * security/tomoyo/audit.c
  *
  * Copyright (C) 2005-2011  NTT DATA CORPORATION
  */

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

 /**
  * tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
  *
  * @bprm: Pointer to "struct linux_binprm".
  * @dump: Pointer to "struct tomoyo_page_dump".
  *
  * Returns the contents of @bprm on success, NULL otherwise.
  *
  * This function uses kzalloc(), so caller must kfree() if this function
  * didn't return NULL.
  */
 static char *tomoyo_print_bprm(struct linux_binprm *bprm,
 			       struct tomoyo_page_dump *dump)
 {
 	static const int tomoyo_buffer_len = 4096 * 2;
 	char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
 	char *cp;
 	char *last_start;
 	int len;
 	unsigned long pos = bprm->p;
 	int offset = pos % PAGE_SIZE;
 	int argv_count = bprm->argc;
 	int envp_count = bprm->envc;
 	bool truncated = false;
 	if (!buffer)
 		return NULL;
 	len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
 	cp = buffer + len;
 	if (!argv_count) {
 		memmove(cp, "} envp[]={ ", 11);
 		cp += 11;
 	}
 	last_start = cp;
 	while (argv_count || envp_count) {
 		if (!tomoyo_dump_page(bprm, pos, dump))
 			goto out;
 		pos += PAGE_SIZE - offset;
 		/* Read. */
 		while (offset < PAGE_SIZE) {
 			const char *kaddr = dump->data;
 			const unsigned char c = kaddr[offset++];
 			if (cp == last_start)
 				*cp++ = '"';
 			if (cp >= buffer + tomoyo_buffer_len - 32) {
 				/* Reserve some room for "..." string. */
 				truncated = true;
 			} else if (c == '\\') {
 				*cp++ = '\\';
 				*cp++ = '\\';
 			} else if (c > ' ' && c < 127) {
 				*cp++ = c;
 			} else if (!c) {
 				*cp++ = '"';
 				*cp++ = ' ';
 				last_start = cp;
 			} else {
 				*cp++ = '\\';
 				*cp++ = (c >> 6) + '0';
 				*cp++ = ((c >> 3) & 7) + '0';
 				*cp++ = (c & 7) + '0';
 			}
 			if (c)
 				continue;
 			if (argv_count) {
 				if (--argv_count == 0) {
 					if (truncated) {
 						cp = last_start;
 						memmove(cp, "... ", 4);
 						cp += 4;
 					}
 					memmove(cp, "} envp[]={ ", 11);
 					cp += 11;
 					last_start = cp;
 					truncated = false;
 				}
 			} else if (envp_count) {
 				if (--envp_count == 0) {
 					if (truncated) {
 						cp = last_start;
 						memmove(cp, "... ", 4);
 						cp += 4;
 					}
 				}
 			}
 			if (!argv_count && !envp_count)
 				break;
 		}
 		offset = 0;
 	}
 	*cp++ = '}';
 	*cp = '\0';
 	return buffer;
 out:
 	snprintf(buffer, tomoyo_buffer_len - 1,
 		 "argv[]={ ... } envp[]= { ... }");
 	return buffer;
 }

 /**
  * tomoyo_filetype - Get string representation of file type.
  *
  * @mode: Mode value for stat().
  *
  * Returns file type string.
  */
 static inline const char *tomoyo_filetype(const mode_t mode)
 {
 	switch (mode & S_IFMT) {
 	case S_IFREG:
 	case 0:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
 	case S_IFDIR:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
 	case S_IFLNK:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
 	case S_IFIFO:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
 	case S_IFSOCK:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
 	case S_IFBLK:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
 	case S_IFCHR:
 		return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
 	}
 	return "unknown"; /* This should not happen. */
 }

 /**
  * 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);
 	struct tomoyo_obj_info *obj = r->obj;
 	static const int tomoyo_buffer_len = 4096;
 	char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
 	int pos;
 	u8 i;
 	if (!buffer)
 		return NULL;
 	{
 		struct timeval tv;
 		do_gettimeofday(&tv);
 		tomoyo_convert_time(tv.tv_sec, &stamp);
 	}
 	pos = 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,
 		       tomoyo_sys_getpid(), tomoyo_sys_getppid(),
 		       current_uid(), current_gid(), current_euid(),
 		       current_egid(), current_suid(), current_sgid(),
 		       current_fsuid(), current_fsgid());
 	if (!obj)
 		goto no_obj_info;
 	if (!obj->validate_done) {
 		tomoyo_get_attributes(obj);
 		obj->validate_done = true;
 	}
 	for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
 		struct tomoyo_mini_stat *stat;
 		unsigned int dev;
 		mode_t mode;
 		if (!obj->stat_valid[i])
 			continue;
 		stat = &obj->stat[i];
 		dev = stat->dev;
 		mode = stat->mode;
 		if (i & 1) {
 			pos += snprintf(buffer + pos,
 					tomoyo_buffer_len - 1 - pos,
 					" path%u.parent={ uid=%u gid=%u "
 					"ino=%lu perm=0%o }", (i >> 1) + 1,
 					stat->uid, stat->gid, (unsigned long)
 					stat->ino, stat->mode & S_IALLUGO);
 			continue;
 		}
 		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 				" path%u={ uid=%u gid=%u ino=%lu major=%u"
 				" minor=%u perm=0%o type=%s", (i >> 1) + 1,
 				stat->uid, stat->gid, (unsigned long)
 				stat->ino, MAJOR(dev), MINOR(dev),
 				mode & S_IALLUGO, tomoyo_filetype(mode));
 		if (S_ISCHR(mode) || S_ISBLK(mode)) {
 			dev = stat->rdev;
 			pos += snprintf(buffer + pos,
 					tomoyo_buffer_len - 1 - pos,
 					" dev_major=%u dev_minor=%u",
 					MAJOR(dev), MINOR(dev));
 		}
 		pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
 				" }");
 	}
 no_obj_info:
 	if (pos < tomoyo_buffer_len - 1)
 		return buffer;
 	kfree(buffer);
 	return NULL;
 }

 /**
  * 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;
 	char *bprm_info = NULL;
 	const char *header = NULL;
 	char *realpath = NULL;
 	const char *symlink = NULL;
 	int pos;
 	const char *domainname = r->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;
 	if (r->ee) {
 		struct file *file = r->ee->bprm->file;
 		realpath = tomoyo_realpath_from_path(&file->f_path);
 		bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
 		if (!realpath || !bprm_info)
 			goto out;
 		/* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
 		len += strlen(realpath) + 80 + strlen(bprm_info);
 	} else if (r->obj && r->obj->symlink_target) {
 		symlink = r->obj->symlink_target->name;
 		/* +18 is for " symlink.target=\"%s\"" */
 		len += 18 + strlen(symlink);
 	}
 	len = tomoyo_round2(len);
 	buf = kzalloc(len, GFP_NOFS);
 	if (!buf)
 		goto out;
 	len--;
 	pos = snprintf(buf, len, "%s", header);
 	if (realpath) {
 		struct linux_binprm *bprm = r->ee->bprm;
 		pos += snprintf(buf + pos, len - pos,
 				" exec={ realpath=\"%s\" argc=%d envc=%d %s }",
 				realpath, bprm->argc, bprm->envc, bprm_info);
 	} else if (symlink)
 		pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
 				symlink);
 	pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
 	vsnprintf(buf + pos, len - pos, fmt, args);
 out:
 	kfree(realpath);
 	kfree(bprm_info);
 	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.
  *
  * @ns:          Pointer to "struct tomoyo_policy_namespace".
  * @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 struct tomoyo_policy_namespace *ns,
 			     const u8 profile, const u8 index,
 			     const bool is_granted)
 {
 	u8 mode;
 	const u8 category = tomoyo_index2category[index] +
 		TOMOYO_MAX_MAC_INDEX;
 	struct tomoyo_profile *p;
 	if (!tomoyo_policy_loaded)
 		return false;
 	p = tomoyo_profile(ns, 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->domain->ns, 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;
 }
	/*
	* security/tomoyo/audit.c
	*
	* Copyright (C) 2005-2011 NTT DATA CORPORATION
	*/

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

	/**
	* tomoyo_print_bprm - Print "struct linux_binprm" for auditing.
	*
	* @bprm: Pointer to "struct linux_binprm".
	* @dump: Pointer to "struct tomoyo_page_dump".
	*
	* Returns the contents of @bprm on success, NULL otherwise.
	*
	* This function uses kzalloc(), so caller must kfree() if this function
	* didn't return NULL.
	*/
	static char tomoyo_print_bprm(struct linux_binprm bprm,
	struct tomoyo_page_dump *dump)
	{
	static const int tomoyo_buffer_len = 4096 * 2;
	char *buffer = kzalloc(tomoyo_buffer_len, GFP_NOFS);
	char *cp;
	char *last_start;
	int len;
	unsigned long pos = bprm->p;
	int offset = pos % PAGE_SIZE;
	int argv_count = bprm->argc;
	int envp_count = bprm->envc;
	bool truncated = false;
	if (!buffer)
	return NULL;
	len = snprintf(buffer, tomoyo_buffer_len - 1, "argv[]={ ");
	cp = buffer + len;
	if (!argv_count) {
	memmove(cp, "} envp[]={ ", 11);
	cp += 11;
	}
	last_start = cp;
	while (argv_count \|\| envp_count) {
	if (!tomoyo_dump_page(bprm, pos, dump))
	goto out;
	pos += PAGE_SIZE - offset;
	/* Read. */
	while (offset < PAGE_SIZE) {
	const char *kaddr = dump->data;
	const unsigned char c = kaddr[offset++];
	if (cp == last_start)
	*cp++ = '"';
	if (cp >= buffer + tomoyo_buffer_len - 32) {
	/* Reserve some room for "..." string. */
	truncated = true;
	} else if (c == '\\') {
	*cp++ = '\\';
	*cp++ = '\\';
	} else if (c > ' ' && c < 127) {
	*cp++ = c;
	} else if (!c) {
	*cp++ = '"';
	*cp++ = ' ';
	last_start = cp;
	} else {
	*cp++ = '\\';
	*cp++ = (c >> 6) + '0';
	*cp++ = ((c >> 3) & 7) + '0';
	*cp++ = (c & 7) + '0';
	}
	if (c)
	continue;
	if (argv_count) {
	if (--argv_count == 0) {
	if (truncated) {
	cp = last_start;
	memmove(cp, "... ", 4);
	cp += 4;
	}
	memmove(cp, "} envp[]={ ", 11);
	cp += 11;
	last_start = cp;
	truncated = false;
	}
	} else if (envp_count) {
	if (--envp_count == 0) {
	if (truncated) {
	cp = last_start;
	memmove(cp, "... ", 4);
	cp += 4;
	}
	}
	}
	if (!argv_count && !envp_count)
	break;
	}
	offset = 0;
	}
	*cp++ = '}';
	*cp = '\0';
	return buffer;
	out:
	snprintf(buffer, tomoyo_buffer_len - 1,
	"argv[]={ ... } envp[]= { ... }");
	return buffer;
	}

	/**
	* tomoyo_filetype - Get string representation of file type.
	*
	* @mode: Mode value for stat().
	*
	* Returns file type string.
	*/
	static inline const char *tomoyo_filetype(const mode_t mode)
	{
	switch (mode & S_IFMT) {
	case S_IFREG:
	case 0:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FILE];
	case S_IFDIR:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_DIRECTORY];
	case S_IFLNK:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SYMLINK];
	case S_IFIFO:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_FIFO];
	case S_IFSOCK:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_SOCKET];
	case S_IFBLK:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_BLOCK_DEV];
	case S_IFCHR:
	return tomoyo_condition_keyword[TOMOYO_TYPE_IS_CHAR_DEV];
	}
	return "unknown"; /* This should not happen. */
	}

	/**
	* 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);
	struct tomoyo_obj_info *obj = r->obj;
	static const int tomoyo_buffer_len = 4096;
	char *buffer = kmalloc(tomoyo_buffer_len, GFP_NOFS);
	int pos;
	u8 i;
	if (!buffer)
	return NULL;
	{
	struct timeval tv;
	do_gettimeofday(&tv);
	tomoyo_convert_time(tv.tv_sec, &stamp);
	}
	pos = 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,
	tomoyo_sys_getpid(), tomoyo_sys_getppid(),
	current_uid(), current_gid(), current_euid(),
	current_egid(), current_suid(), current_sgid(),
	current_fsuid(), current_fsgid());
	if (!obj)
	goto no_obj_info;
	if (!obj->validate_done) {
	tomoyo_get_attributes(obj);
	obj->validate_done = true;
	}
	for (i = 0; i < TOMOYO_MAX_PATH_STAT; i++) {
	struct tomoyo_mini_stat *stat;
	unsigned int dev;
	mode_t mode;
	if (!obj->stat_valid[i])
	continue;
	stat = &obj->stat[i];
	dev = stat->dev;
	mode = stat->mode;
	if (i & 1) {
	pos += snprintf(buffer + pos,
	tomoyo_buffer_len - 1 - pos,
	" path%u.parent={ uid=%u gid=%u "
	"ino=%lu perm=0%o }", (i >> 1) + 1,
	stat->uid, stat->gid, (unsigned long)
	stat->ino, stat->mode & S_IALLUGO);
	continue;
	}
	pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
	" path%u={ uid=%u gid=%u ino=%lu major=%u"
	" minor=%u perm=0%o type=%s", (i >> 1) + 1,
	stat->uid, stat->gid, (unsigned long)
	stat->ino, MAJOR(dev), MINOR(dev),
	mode & S_IALLUGO, tomoyo_filetype(mode));
	if (S_ISCHR(mode) \|\| S_ISBLK(mode)) {
	dev = stat->rdev;
	pos += snprintf(buffer + pos,
	tomoyo_buffer_len - 1 - pos,
	" dev_major=%u dev_minor=%u",
	MAJOR(dev), MINOR(dev));
	}
	pos += snprintf(buffer + pos, tomoyo_buffer_len - 1 - pos,
	" }");
	}
	no_obj_info:
	if (pos < tomoyo_buffer_len - 1)
	return buffer;
	kfree(buffer);
	return NULL;
	}

	/**
	* 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;
	char *bprm_info = NULL;
	const char *header = NULL;
	char *realpath = NULL;
	const char *symlink = NULL;
	int pos;
	const char *domainname = r->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;
	if (r->ee) {
	struct file *file = r->ee->bprm->file;
	realpath = tomoyo_realpath_from_path(&file->f_path);
	bprm_info = tomoyo_print_bprm(r->ee->bprm, &r->ee->dump);
	if (!realpath \|\| !bprm_info)
	goto out;
	/* +80 is for " exec={ realpath=\"%s\" argc=%d envc=%d %s }" */
	len += strlen(realpath) + 80 + strlen(bprm_info);
	} else if (r->obj && r->obj->symlink_target) {
	symlink = r->obj->symlink_target->name;
	/* +18 is for " symlink.target=\"%s\"" */
	len += 18 + strlen(symlink);
	}
	len = tomoyo_round2(len);
	buf = kzalloc(len, GFP_NOFS);
	if (!buf)
	goto out;
	len--;
	pos = snprintf(buf, len, "%s", header);
	if (realpath) {
	struct linux_binprm *bprm = r->ee->bprm;
	pos += snprintf(buf + pos, len - pos,
	" exec={ realpath=\"%s\" argc=%d envc=%d %s }",
	realpath, bprm->argc, bprm->envc, bprm_info);
	} else if (symlink)
	pos += snprintf(buf + pos, len - pos, " symlink.target=\"%s\"",
	symlink);
	pos += snprintf(buf + pos, len - pos, "\n%s\n", domainname);
	vsnprintf(buf + pos, len - pos, fmt, args);
	out:
	kfree(realpath);
	kfree(bprm_info);
	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.
	*
	* @ns: Pointer to "struct tomoyo_policy_namespace".
	* @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 struct tomoyo_policy_namespace *ns,
	const u8 profile, const u8 index,
	const bool is_granted)
	{
	u8 mode;
	const u8 category = tomoyo_index2category[index] +
	TOMOYO_MAX_MAC_INDEX;
	struct tomoyo_profile *p;
	if (!tomoyo_policy_loaded)
	return false;
	p = tomoyo_profile(ns, 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->domain->ns, 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;
	}