File operation restriction part.

This file controls file related operations of TOMOYO Linux.

tomoyo/tomoyo.c calls the following six functions in this file.
Each function handles the following access types.

 * tomoyo_check_file_perm
sysctl()'s "read" and "write".

 * tomoyo_check_exec_perm
"execute".

 * tomoyo_check_open_permission
open(2) for "read" and "write".

 * tomoyo_check_1path_perm
"create", "unlink", "mkdir", "rmdir", "mkfifo",
"mksock", "mkblock", "mkchar", "truncate" and "symlink".

 * tomoyo_check_2path_perm
"rename" and "unlink".

 * tomoyo_check_rewrite_permission
"rewrite".
("rewrite" are operations which may lose already recorded data of a file,
i.e. open(!O_APPEND) || open(O_TRUNC) || truncate() || ftruncate())

The functions which actually checks ACLs are the following three functions.
Each function handles the following access types.
ACL directive is expressed by "allow_<access type>".

 * tomoyo_check_file_acl
Open() operation and execve() operation.
("read", "write", "read/write" and "execute")

 * tomoyo_check_single_write_acl
Directory modification operations with 1 pathname.
("create", "unlink", "mkdir", "rmdir", "mkfifo", "mksock",
 "mkblock", "mkchar", "truncate", "symlink" and "rewrite")

 * tomoyo_check_double_write_acl
Directory modification operations with 2 pathname.
("link" and "rename")

Also, this file contains handlers of some utility directives
for file related operations.

 * "allow_read":   specifies globally (for all domains) readable files.
 * "path_group":   specifies pathname macro.
 * "deny_rewrite": restricts rewrite operation.

Signed-off-by: Kentaro Takeda <takedakn@nttdata.co.jp>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toshiharu Harada <haradats@nttdata.co.jp>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 1241 insertions, 0 deletions

diff --git a/security/tomoyo/file.c b/security/tomoyo/file.c
new file mode 100644
index 0000000..65f50c1
--- /dev/null
+++ b/security/tomoyo/file.c
@@ -0,0 +1,1241 @@
+/*
+ * security/tomoyo/file.c
+ *
+ * Implementation of the Domain-Based Mandatory Access Control.
+ *
+ * Copyright (C) 2005-2009  NTT DATA CORPORATION
+ *
+ * Version: 2.2.0-pre   2009/02/01
+ *
+ */
+
+#include "common.h"
+#include "tomoyo.h"
+#include "realpath.h"
+#define ACC_MODE(x) ("\000\004\002\006"[(x)&O_ACCMODE])
+
+/* Structure for "allow_read" keyword. */
+struct tomoyo_globally_readable_file_entry {
+	struct list_head list;
+	const struct tomoyo_path_info *filename;
+	bool is_deleted;
+};
+
+/* Structure for "file_pattern" keyword. */
+struct tomoyo_pattern_entry {
+	struct list_head list;
+	const struct tomoyo_path_info *pattern;
+	bool is_deleted;
+};
+
+/* Structure for "deny_rewrite" keyword. */
+struct tomoyo_no_rewrite_entry {
+	struct list_head list;
+	const struct tomoyo_path_info *pattern;
+	bool is_deleted;
+};
+
+/* Keyword array for single path operations. */
+static const char *tomoyo_sp_keyword[TOMOYO_MAX_SINGLE_PATH_OPERATION] = {
+	[TOMOYO_TYPE_READ_WRITE_ACL] = "read/write",
+	[TOMOYO_TYPE_EXECUTE_ACL]    = "execute",
+	[TOMOYO_TYPE_READ_ACL]       = "read",
+	[TOMOYO_TYPE_WRITE_ACL]      = "write",
+	[TOMOYO_TYPE_CREATE_ACL]     = "create",
+	[TOMOYO_TYPE_UNLINK_ACL]     = "unlink",
+	[TOMOYO_TYPE_MKDIR_ACL]      = "mkdir",
+	[TOMOYO_TYPE_RMDIR_ACL]      = "rmdir",
+	[TOMOYO_TYPE_MKFIFO_ACL]     = "mkfifo",
+	[TOMOYO_TYPE_MKSOCK_ACL]     = "mksock",
+	[TOMOYO_TYPE_MKBLOCK_ACL]    = "mkblock",
+	[TOMOYO_TYPE_MKCHAR_ACL]     = "mkchar",
+	[TOMOYO_TYPE_TRUNCATE_ACL]   = "truncate",
+	[TOMOYO_TYPE_SYMLINK_ACL]    = "symlink",
+	[TOMOYO_TYPE_REWRITE_ACL]    = "rewrite",
+};
+
+/* Keyword array for double path operations. */
+static const char *tomoyo_dp_keyword[TOMOYO_MAX_DOUBLE_PATH_OPERATION] = {
+	[TOMOYO_TYPE_LINK_ACL]    = "link",
+	[TOMOYO_TYPE_RENAME_ACL]  = "rename",
+};
+
+/**
+ * tomoyo_sp2keyword - Get the name of single path operation.
+ *
+ * @operation: Type of operation.
+ *
+ * Returns the name of single path operation.
+ */
+const char *tomoyo_sp2keyword(const u8 operation)
+{
+	return (operation < TOMOYO_MAX_SINGLE_PATH_OPERATION)
+		? tomoyo_sp_keyword[operation] : NULL;
+}
+
+/**
+ * tomoyo_dp2keyword - Get the name of double path operation.
+ *
+ * @operation: Type of operation.
+ *
+ * Returns the name of double path operation.
+ */
+const char *tomoyo_dp2keyword(const u8 operation)
+{
+	return (operation < TOMOYO_MAX_DOUBLE_PATH_OPERATION)
+		? tomoyo_dp_keyword[operation] : NULL;
+}
+
+/**
+ * tomoyo_strendswith - Check whether the token ends with the given token.
+ *
+ * @name: The token to check.
+ * @tail: The token to find.
+ *
+ * Returns true if @name ends with @tail, false otherwise.
+ */
+static bool tomoyo_strendswith(const char *name, const char *tail)
+{
+	int len;
+
+	if (!name || !tail)
+		return false;
+	len = strlen(name) - strlen(tail);
+	return len >= 0 && !strcmp(name + len, tail);
+}
+
+/**
+ * tomoyo_get_path - Get realpath.
+ *
+ * @path: Pointer to "struct path".
+ *
+ * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise.
+ */
+static struct tomoyo_path_info *tomoyo_get_path(struct path *path)
+{
+	int error;
+	struct tomoyo_path_info_with_data *buf = tomoyo_alloc(sizeof(*buf));
+
+	if (!buf)
+		return NULL;
+	/* Reserve one byte for appending "/". */
+	error = tomoyo_realpath_from_path2(path, buf->body,
+					   sizeof(buf->body) - 2);
+	if (!error) {
+		buf->head.name = buf->body;
+		tomoyo_fill_path_info(&buf->head);
+		return &buf->head;
+	}
+	tomoyo_free(buf);
+	return NULL;
+}
+
+/* Lock for domain->acl_info_list. */
+DECLARE_RWSEM(tomoyo_domain_acl_info_list_lock);
+
+static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
+					 const char *filename2,
+					 struct tomoyo_domain_info *
+					 const domain, const bool is_delete);
+static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
+					 struct tomoyo_domain_info *
+					 const domain, const bool is_delete);
+
+/* The list for "struct tomoyo_globally_readable_file_entry". */
+static LIST_HEAD(tomoyo_globally_readable_list);
+static DECLARE_RWSEM(tomoyo_globally_readable_list_lock);
+
+/**
+ * tomoyo_update_globally_readable_entry - Update "struct tomoyo_globally_readable_file_entry" list.
+ *
+ * @filename:  Filename unconditionally permitted to open() for reading.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_update_globally_readable_entry(const char *filename,
+						 const bool is_delete)
+{
+	struct tomoyo_globally_readable_file_entry *new_entry;
+	struct tomoyo_globally_readable_file_entry *ptr;
+	const struct tomoyo_path_info *saved_filename;
+	int error = -ENOMEM;
+
+	if (!tomoyo_is_correct_path(filename, 1, 0, -1, __func__))
+		return -EINVAL;
+	saved_filename = tomoyo_save_name(filename);
+	if (!saved_filename)
+		return -ENOMEM;
+	/***** EXCLUSIVE SECTION START *****/
+	down_write(&tomoyo_globally_readable_list_lock);
+	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+		if (ptr->filename != saved_filename)
+			continue;
+		ptr->is_deleted = is_delete;
+		error = 0;
+		goto out;
+	}
+	if (is_delete) {
+		error = -ENOENT;
+		goto out;
+	}
+	new_entry = tomoyo_alloc_element(sizeof(*new_entry));
+	if (!new_entry)
+		goto out;
+	new_entry->filename = saved_filename;
+	list_add_tail(&new_entry->list, &tomoyo_globally_readable_list);
+	error = 0;
+ out:
+	up_write(&tomoyo_globally_readable_list_lock);
+	/***** EXCLUSIVE SECTION END *****/
+	return error;
+}
+
+/**
+ * tomoyo_is_globally_readable_file - Check if the file is unconditionnaly permitted to be open()ed for reading.
+ *
+ * @filename: The filename to check.
+ *
+ * Returns true if any domain can open @filename for reading, false otherwise.
+ */
+static bool tomoyo_is_globally_readable_file(const struct tomoyo_path_info *
+					     filename)
+{
+	struct tomoyo_globally_readable_file_entry *ptr;
+	bool found = false;
+	down_read(&tomoyo_globally_readable_list_lock);
+	list_for_each_entry(ptr, &tomoyo_globally_readable_list, list) {
+		if (!ptr->is_deleted &&
+		    tomoyo_path_matches_pattern(filename, ptr->filename)) {
+			found = true;
+			break;
+		}
+	}
+	up_read(&tomoyo_globally_readable_list_lock);
+	return found;
+}
+
+/**
+ * tomoyo_write_globally_readable_policy - Write "struct tomoyo_globally_readable_file_entry" list.
+ *
+ * @data:      String to parse.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_globally_readable_policy(char *data, const bool is_delete)
+{
+	return tomoyo_update_globally_readable_entry(data, is_delete);
+}
+
+/**
+ * tomoyo_read_globally_readable_policy - Read "struct tomoyo_globally_readable_file_entry" list.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns true on success, false otherwise.
+ */
+bool tomoyo_read_globally_readable_policy(struct tomoyo_io_buffer *head)
+{
+	struct list_head *pos;
+	bool done = true;
+
+	down_read(&tomoyo_globally_readable_list_lock);
+	list_for_each_cookie(pos, head->read_var2,
+			     &tomoyo_globally_readable_list) {
+		struct tomoyo_globally_readable_file_entry *ptr;
+		ptr = list_entry(pos,
+				 struct tomoyo_globally_readable_file_entry,
+				 list);
+		if (ptr->is_deleted)
+			continue;
+		if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_ALLOW_READ "%s\n",
+				      ptr->filename->name)) {
+			done = false;
+			break;
+		}
+	}
+	up_read(&tomoyo_globally_readable_list_lock);
+	return done;
+}
+
+/* The list for "struct tomoyo_pattern_entry". */
+static LIST_HEAD(tomoyo_pattern_list);
+static DECLARE_RWSEM(tomoyo_pattern_list_lock);
+
+/**
+ * tomoyo_update_file_pattern_entry - Update "struct tomoyo_pattern_entry" list.
+ *
+ * @pattern:   Pathname pattern.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_update_file_pattern_entry(const char *pattern,
+					    const bool is_delete)
+{
+	struct tomoyo_pattern_entry *new_entry;
+	struct tomoyo_pattern_entry *ptr;
+	const struct tomoyo_path_info *saved_pattern;
+	int error = -ENOMEM;
+
+	if (!tomoyo_is_correct_path(pattern, 0, 1, 0, __func__))
+		return -EINVAL;
+	saved_pattern = tomoyo_save_name(pattern);
+	if (!saved_pattern)
+		return -ENOMEM;
+	/***** EXCLUSIVE SECTION START *****/
+	down_write(&tomoyo_pattern_list_lock);
+	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+		if (saved_pattern != ptr->pattern)
+			continue;
+		ptr->is_deleted = is_delete;
+		error = 0;
+		goto out;
+	}
+	if (is_delete) {
+		error = -ENOENT;
+		goto out;
+	}
+	new_entry = tomoyo_alloc_element(sizeof(*new_entry));
+	if (!new_entry)
+		goto out;
+	new_entry->pattern = saved_pattern;
+	list_add_tail(&new_entry->list, &tomoyo_pattern_list);
+	error = 0;
+ out:
+	up_write(&tomoyo_pattern_list_lock);
+	/***** EXCLUSIVE SECTION END *****/
+	return error;
+}
+
+/**
+ * tomoyo_get_file_pattern - Get patterned pathname.
+ *
+ * @filename: The filename to find patterned pathname.
+ *
+ * Returns pointer to pathname pattern if matched, @filename otherwise.
+ */
+static const struct tomoyo_path_info *
+tomoyo_get_file_pattern(const struct tomoyo_path_info *filename)
+{
+	struct tomoyo_pattern_entry *ptr;
+	const struct tomoyo_path_info *pattern = NULL;
+
+	down_read(&tomoyo_pattern_list_lock);
+	list_for_each_entry(ptr, &tomoyo_pattern_list, list) {
+		if (ptr->is_deleted)
+			continue;
+		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
+			continue;
+		pattern = ptr->pattern;
+		if (tomoyo_strendswith(pattern->name, "/\\*")) {
+			/* Do nothing. Try to find the better match. */
+		} else {
+			/* This would be the better match. Use this. */
+			break;
+		}
+	}
+	up_read(&tomoyo_pattern_list_lock);
+	if (pattern)
+		filename = pattern;
+	return filename;
+}
+
+/**
+ * tomoyo_write_pattern_policy - Write "struct tomoyo_pattern_entry" list.
+ *
+ * @data:      String to parse.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_pattern_policy(char *data, const bool is_delete)
+{
+	return tomoyo_update_file_pattern_entry(data, is_delete);
+}
+
+/**
+ * tomoyo_read_file_pattern - Read "struct tomoyo_pattern_entry" list.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns true on success, false otherwise.
+ */
+bool tomoyo_read_file_pattern(struct tomoyo_io_buffer *head)
+{
+	struct list_head *pos;
+	bool done = true;
+
+	down_read(&tomoyo_pattern_list_lock);
+	list_for_each_cookie(pos, head->read_var2, &tomoyo_pattern_list) {
+		struct tomoyo_pattern_entry *ptr;
+		ptr = list_entry(pos, struct tomoyo_pattern_entry, list);
+		if (ptr->is_deleted)
+			continue;
+		if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_FILE_PATTERN "%s\n",
+				      ptr->pattern->name)) {
+			done = false;
+			break;
+		}
+	}
+	up_read(&tomoyo_pattern_list_lock);
+	return done;
+}
+
+/* The list for "struct tomoyo_no_rewrite_entry". */
+static LIST_HEAD(tomoyo_no_rewrite_list);
+static DECLARE_RWSEM(tomoyo_no_rewrite_list_lock);
+
+/**
+ * tomoyo_update_no_rewrite_entry - Update "struct tomoyo_no_rewrite_entry" list.
+ *
+ * @pattern:   Pathname pattern that are not rewritable by default.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_update_no_rewrite_entry(const char *pattern,
+					  const bool is_delete)
+{
+	struct tomoyo_no_rewrite_entry *new_entry, *ptr;
+	const struct tomoyo_path_info *saved_pattern;
+	int error = -ENOMEM;
+
+	if (!tomoyo_is_correct_path(pattern, 0, 0, 0, __func__))
+		return -EINVAL;
+	saved_pattern = tomoyo_save_name(pattern);
+	if (!saved_pattern)
+		return -ENOMEM;
+	/***** EXCLUSIVE SECTION START *****/
+	down_write(&tomoyo_no_rewrite_list_lock);
+	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+		if (ptr->pattern != saved_pattern)
+			continue;
+		ptr->is_deleted = is_delete;
+		error = 0;
+		goto out;
+	}
+	if (is_delete) {
+		error = -ENOENT;
+		goto out;
+	}
+	new_entry = tomoyo_alloc_element(sizeof(*new_entry));
+	if (!new_entry)
+		goto out;
+	new_entry->pattern = saved_pattern;
+	list_add_tail(&new_entry->list, &tomoyo_no_rewrite_list);
+	error = 0;
+ out:
+	up_write(&tomoyo_no_rewrite_list_lock);
+	/***** EXCLUSIVE SECTION END *****/
+	return error;
+}
+
+/**
+ * tomoyo_is_no_rewrite_file - Check if the given pathname is not permitted to be rewrited.
+ *
+ * @filename: Filename to check.
+ *
+ * Returns true if @filename is specified by "deny_rewrite" directive,
+ * false otherwise.
+ */
+static bool tomoyo_is_no_rewrite_file(const struct tomoyo_path_info *filename)
+{
+	struct tomoyo_no_rewrite_entry *ptr;
+	bool found = false;
+
+	down_read(&tomoyo_no_rewrite_list_lock);
+	list_for_each_entry(ptr, &tomoyo_no_rewrite_list, list) {
+		if (ptr->is_deleted)
+			continue;
+		if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
+			continue;
+		found = true;
+		break;
+	}
+	up_read(&tomoyo_no_rewrite_list_lock);
+	return found;
+}
+
+/**
+ * tomoyo_write_no_rewrite_policy - Write "struct tomoyo_no_rewrite_entry" list.
+ *
+ * @data:      String to parse.
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_no_rewrite_policy(char *data, const bool is_delete)
+{
+	return tomoyo_update_no_rewrite_entry(data, is_delete);
+}
+
+/**
+ * tomoyo_read_no_rewrite_policy - Read "struct tomoyo_no_rewrite_entry" list.
+ *
+ * @head: Pointer to "struct tomoyo_io_buffer".
+ *
+ * Returns true on success, false otherwise.
+ */
+bool tomoyo_read_no_rewrite_policy(struct tomoyo_io_buffer *head)
+{
+	struct list_head *pos;
+	bool done = true;
+
+	down_read(&tomoyo_no_rewrite_list_lock);
+	list_for_each_cookie(pos, head->read_var2, &tomoyo_no_rewrite_list) {
+		struct tomoyo_no_rewrite_entry *ptr;
+		ptr = list_entry(pos, struct tomoyo_no_rewrite_entry, list);
+		if (ptr->is_deleted)
+			continue;
+		if (!tomoyo_io_printf(head, TOMOYO_KEYWORD_DENY_REWRITE "%s\n",
+				      ptr->pattern->name)) {
+			done = false;
+			break;
+		}
+	}
+	up_read(&tomoyo_no_rewrite_list_lock);
+	return done;
+}
+
+/**
+ * tomoyo_update_file_acl - Update file's read/write/execute ACL.
+ *
+ * @filename:  Filename.
+ * @perm:      Permission (between 1 to 7).
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ *
+ * This is legacy support interface for older policy syntax.
+ * Current policy syntax uses "allow_read/write" instead of "6",
+ * "allow_read" instead of "4", "allow_write" instead of "2",
+ * "allow_execute" instead of "1".
+ */
+static int tomoyo_update_file_acl(const char *filename, u8 perm,
+				  struct tomoyo_domain_info * const domain,
+				  const bool is_delete)
+{
+	if (perm > 7 || !perm) {
+		printk(KERN_DEBUG "%s: Invalid permission '%d %s'\n",
+		       __func__, perm, filename);
+		return -EINVAL;
+	}
+	if (filename[0] != '@' && tomoyo_strendswith(filename, "/"))
+		/*
+		 * Only 'allow_mkdir' and 'allow_rmdir' are valid for
+		 * directory permissions.
+		 */
+		return 0;
+	if (perm & 4)
+		tomoyo_update_single_path_acl(TOMOYO_TYPE_READ_ACL, filename,
+					      domain, is_delete);
+	if (perm & 2)
+		tomoyo_update_single_path_acl(TOMOYO_TYPE_WRITE_ACL, filename,
+					      domain, is_delete);
+	if (perm & 1)
+		tomoyo_update_single_path_acl(TOMOYO_TYPE_EXECUTE_ACL,
+					      filename, domain, is_delete);
+	return 0;
+}
+
+/**
+ * tomoyo_check_single_path_acl2 - Check permission for single path operation.
+ *
+ * @domain:          Pointer to "struct tomoyo_domain_info".
+ * @filename:        Filename to check.
+ * @perm:            Permission.
+ * @may_use_pattern: True if patterned ACL is permitted.
+ *
+ * Returns 0 on success, -EPERM otherwise.
+ */
+static int tomoyo_check_single_path_acl2(const struct tomoyo_domain_info *
+					 domain,
+					 const struct tomoyo_path_info *
+					 filename,
+					 const u16 perm,
+					 const bool may_use_pattern)
+{
+	struct tomoyo_acl_info *ptr;
+	int error = -EPERM;
+
+	down_read(&tomoyo_domain_acl_info_list_lock);
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		struct tomoyo_single_path_acl_record *acl;
+		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
+				   head);
+		if (!(acl->perm & perm))
+			continue;
+		if (may_use_pattern || !acl->filename->is_patterned) {
+			if (!tomoyo_path_matches_pattern(filename,
+							 acl->filename))
+				continue;
+		} else {
+			continue;
+		}
+		error = 0;
+		break;
+	}
+	up_read(&tomoyo_domain_acl_info_list_lock);
+	return error;
+}
+
+/**
+ * tomoyo_check_file_acl - Check permission for opening files.
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @filename:  Filename to check.
+ * @operation: Mode ("read" or "write" or "read/write" or "execute").
+ *
+ * Returns 0 on success, -EPERM otherwise.
+ */
+static int tomoyo_check_file_acl(const struct tomoyo_domain_info *domain,
+				 const struct tomoyo_path_info *filename,
+				 const u8 operation)
+{
+	u16 perm = 0;
+
+	if (!tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE))
+		return 0;
+	if (operation == 6)
+		perm = 1 << TOMOYO_TYPE_READ_WRITE_ACL;
+	else if (operation == 4)
+		perm = 1 << TOMOYO_TYPE_READ_ACL;
+	else if (operation == 2)
+		perm = 1 << TOMOYO_TYPE_WRITE_ACL;
+	else if (operation == 1)
+		perm = 1 << TOMOYO_TYPE_EXECUTE_ACL;
+	else
+		BUG();
+	return tomoyo_check_single_path_acl2(domain, filename, perm,
+					     operation != 1);
+}
+
+/**
+ * tomoyo_check_file_perm2 - Check permission for opening files.
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @filename:  Filename to check.
+ * @perm:      Mode ("read" or "write" or "read/write" or "execute").
+ * @operation: Operation name passed used for verbose mode.
+ * @mode:      Access control mode.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_check_file_perm2(struct tomoyo_domain_info * const domain,
+				   const struct tomoyo_path_info *filename,
+				   const u8 perm, const char *operation,
+				   const u8 mode)
+{
+	const bool is_enforce = (mode == 3);
+	const char *msg = "<unknown>";
+	int error = 0;
+
+	if (!filename)
+		return 0;
+	error = tomoyo_check_file_acl(domain, filename, perm);
+	if (error && perm == 4 &&
+	    (domain->flags & TOMOYO_DOMAIN_FLAGS_IGNORE_GLOBAL_ALLOW_READ) == 0
+	    && tomoyo_is_globally_readable_file(filename))
+		error = 0;
+	if (perm == 6)
+		msg = tomoyo_sp2keyword(TOMOYO_TYPE_READ_WRITE_ACL);
+	else if (perm == 4)
+		msg = tomoyo_sp2keyword(TOMOYO_TYPE_READ_ACL);
+	else if (perm == 2)
+		msg = tomoyo_sp2keyword(TOMOYO_TYPE_WRITE_ACL);
+	else if (perm == 1)
+		msg = tomoyo_sp2keyword(TOMOYO_TYPE_EXECUTE_ACL);
+	else
+		BUG();
+	if (!error)
+		return 0;
+	if (tomoyo_verbose_mode(domain))
+		printk(KERN_WARNING "TOMOYO-%s: Access '%s(%s) %s' denied "
+		       "for %s\n", tomoyo_get_msg(is_enforce), msg, operation,
+		       filename->name, tomoyo_get_last_name(domain));
+	if (is_enforce)
+		return error;
+	if (mode == 1 && tomoyo_domain_quota_is_ok(domain)) {
+		/* Don't use patterns for execute permission. */
+		const struct tomoyo_path_info *patterned_file = (perm != 1) ?
+			tomoyo_get_file_pattern(filename) : filename;
+		tomoyo_update_file_acl(patterned_file->name, perm,
+				       domain, false);
+	}
+	return 0;
+}
+
+/**
+ * tomoyo_write_file_policy - Update file related list.
+ *
+ * @data:      String to parse.
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_write_file_policy(char *data, struct tomoyo_domain_info *domain,
+			     const bool is_delete)
+{
+	char *filename = strchr(data, ' ');
+	char *filename2;
+	unsigned int perm;
+	u8 type;
+
+	if (!filename)
+		return -EINVAL;
+	*filename++ = '\0';
+	if (sscanf(data, "%u", &perm) == 1)
+		return tomoyo_update_file_acl(filename, (u8) perm, domain,
+					      is_delete);
+	if (strncmp(data, "allow_", 6))
+		goto out;
+	data += 6;
+	for (type = 0; type < TOMOYO_MAX_SINGLE_PATH_OPERATION; type++) {
+		if (strcmp(data, tomoyo_sp_keyword[type]))
+			continue;
+		return tomoyo_update_single_path_acl(type, filename,
+						     domain, is_delete);
+	}
+	filename2 = strchr(filename, ' ');
+	if (!filename2)
+		goto out;
+	*filename2++ = '\0';
+	for (type = 0; type < TOMOYO_MAX_DOUBLE_PATH_OPERATION; type++) {
+		if (strcmp(data, tomoyo_dp_keyword[type]))
+			continue;
+		return tomoyo_update_double_path_acl(type, filename, filename2,
+						     domain, is_delete);
+	}
+ out:
+	return -EINVAL;
+}
+
+/**
+ * tomoyo_update_single_path_acl - Update "struct tomoyo_single_path_acl_record" list.
+ *
+ * @type:      Type of operation.
+ * @filename:  Filename.
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_update_single_path_acl(const u8 type, const char *filename,
+					 struct tomoyo_domain_info *
+					 const domain, const bool is_delete)
+{
+	static const u16 rw_mask =
+		(1 << TOMOYO_TYPE_READ_ACL) | (1 << TOMOYO_TYPE_WRITE_ACL);
+	const struct tomoyo_path_info *saved_filename;
+	struct tomoyo_acl_info *ptr;
+	struct tomoyo_single_path_acl_record *acl;
+	int error = -ENOMEM;
+	const u16 perm = 1 << type;
+
+	if (!domain)
+		return -EINVAL;
+	if (!tomoyo_is_correct_path(filename, 0, 0, 0, __func__))
+		return -EINVAL;
+	saved_filename = tomoyo_save_name(filename);
+	if (!saved_filename)
+		return -ENOMEM;
+	/***** EXCLUSIVE SECTION START *****/
+	down_write(&tomoyo_domain_acl_info_list_lock);
+	if (is_delete)
+		goto delete;
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
+				   head);
+		if (acl->filename != saved_filename)
+			continue;
+		/* Special case. Clear all bits if marked as deleted. */
+		if (ptr->type & TOMOYO_ACL_DELETED)
+			acl->perm = 0;
+		acl->perm |= perm;
+		if ((acl->perm & rw_mask) == rw_mask)
+			acl->perm |= 1 << TOMOYO_TYPE_READ_WRITE_ACL;
+		else if (acl->perm & (1 << TOMOYO_TYPE_READ_WRITE_ACL))
+			acl->perm |= rw_mask;
+		ptr->type &= ~TOMOYO_ACL_DELETED;
+		error = 0;
+		goto out;
+	}
+	/* Not found. Append it to the tail. */
+	acl = tomoyo_alloc_acl_element(TOMOYO_TYPE_SINGLE_PATH_ACL);
+	if (!acl)
+		goto out;
+	acl->perm = perm;
+	if (perm == (1 << TOMOYO_TYPE_READ_WRITE_ACL))
+		acl->perm |= rw_mask;
+	acl->filename = saved_filename;
+	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	error = 0;
+	goto out;
+ delete:
+	error = -ENOENT;
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_SINGLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_single_path_acl_record,
+				   head);
+		if (acl->filename != saved_filename)
+			continue;
+		acl->perm &= ~perm;
+		if ((acl->perm & rw_mask) != rw_mask)
+			acl->perm &= ~(1 << TOMOYO_TYPE_READ_WRITE_ACL);
+		else if (!(acl->perm & (1 << TOMOYO_TYPE_READ_WRITE_ACL)))
+			acl->perm &= ~rw_mask;
+		if (!acl->perm)
+			ptr->type |= TOMOYO_ACL_DELETED;
+		error = 0;
+		break;
+	}
+ out:
+	up_write(&tomoyo_domain_acl_info_list_lock);
+	/***** EXCLUSIVE SECTION END *****/
+	return error;
+}
+
+/**
+ * tomoyo_update_double_path_acl - Update "struct tomoyo_double_path_acl_record" list.
+ *
+ * @type:      Type of operation.
+ * @filename1: First filename.
+ * @filename2: Second filename.
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @is_delete: True if it is a delete request.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_update_double_path_acl(const u8 type, const char *filename1,
+					 const char *filename2,
+					 struct tomoyo_domain_info *
+					 const domain, const bool is_delete)
+{
+	const struct tomoyo_path_info *saved_filename1;
+	const struct tomoyo_path_info *saved_filename2;
+	struct tomoyo_acl_info *ptr;
+	struct tomoyo_double_path_acl_record *acl;
+	int error = -ENOMEM;
+	const u8 perm = 1 << type;
+
+	if (!domain)
+		return -EINVAL;
+	if (!tomoyo_is_correct_path(filename1, 0, 0, 0, __func__) ||
+	    !tomoyo_is_correct_path(filename2, 0, 0, 0, __func__))
+		return -EINVAL;
+	saved_filename1 = tomoyo_save_name(filename1);
+	saved_filename2 = tomoyo_save_name(filename2);
+	if (!saved_filename1 || !saved_filename2)
+		return -ENOMEM;
+	/***** EXCLUSIVE SECTION START *****/
+	down_write(&tomoyo_domain_acl_info_list_lock);
+	if (is_delete)
+		goto delete;
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		if (tomoyo_acl_type1(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
+				   head);
+		if (acl->filename1 != saved_filename1 ||
+		    acl->filename2 != saved_filename2)
+			continue;
+		/* Special case. Clear all bits if marked as deleted. */
+		if (ptr->type & TOMOYO_ACL_DELETED)
+			acl->perm = 0;
+		acl->perm |= perm;
+		ptr->type &= ~TOMOYO_ACL_DELETED;
+		error = 0;
+		goto out;
+	}
+	/* Not found. Append it to the tail. */
+	acl = tomoyo_alloc_acl_element(TOMOYO_TYPE_DOUBLE_PATH_ACL);
+	if (!acl)
+		goto out;
+	acl->perm = perm;
+	acl->filename1 = saved_filename1;
+	acl->filename2 = saved_filename2;
+	list_add_tail(&acl->head.list, &domain->acl_info_list);
+	error = 0;
+	goto out;
+ delete:
+	error = -ENOENT;
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
+				   head);
+		if (acl->filename1 != saved_filename1 ||
+		    acl->filename2 != saved_filename2)
+			continue;
+		acl->perm &= ~perm;
+		if (!acl->perm)
+			ptr->type |= TOMOYO_ACL_DELETED;
+		error = 0;
+		break;
+	}
+ out:
+	up_write(&tomoyo_domain_acl_info_list_lock);
+	/***** EXCLUSIVE SECTION END *****/
+	return error;
+}
+
+/**
+ * tomoyo_check_single_path_acl - Check permission for single path operation.
+ *
+ * @domain:   Pointer to "struct tomoyo_domain_info".
+ * @type:     Type of operation.
+ * @filename: Filename to check.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_check_single_path_acl(struct tomoyo_domain_info *domain,
+					const u8 type,
+					const struct tomoyo_path_info *filename)
+{
+	if (!tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE))
+		return 0;
+	return tomoyo_check_single_path_acl2(domain, filename, 1 << type, 1);
+}
+
+/**
+ * tomoyo_check_double_path_acl - Check permission for double path operation.
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @type:      Type of operation.
+ * @filename1: First filename to check.
+ * @filename2: Second filename to check.
+ *
+ * Returns 0 on success, -EPERM otherwise.
+ */
+static int tomoyo_check_double_path_acl(const struct tomoyo_domain_info *domain,
+					const u8 type,
+					const struct tomoyo_path_info *
+					filename1,
+					const struct tomoyo_path_info *
+					filename2)
+{
+	struct tomoyo_acl_info *ptr;
+	const u8 perm = 1 << type;
+	int error = -EPERM;
+
+	if (!tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE))
+		return 0;
+	down_read(&tomoyo_domain_acl_info_list_lock);
+	list_for_each_entry(ptr, &domain->acl_info_list, list) {
+		struct tomoyo_double_path_acl_record *acl;
+		if (tomoyo_acl_type2(ptr) != TOMOYO_TYPE_DOUBLE_PATH_ACL)
+			continue;
+		acl = container_of(ptr, struct tomoyo_double_path_acl_record,
+				   head);
+		if (!(acl->perm & perm))
+			continue;
+		if (!tomoyo_path_matches_pattern(filename1, acl->filename1))
+			continue;
+		if (!tomoyo_path_matches_pattern(filename2, acl->filename2))
+			continue;
+		error = 0;
+		break;
+	}
+	up_read(&tomoyo_domain_acl_info_list_lock);
+	return error;
+}
+
+/**
+ * tomoyo_check_single_path_permission2 - Check permission for single path operation.
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @operation: Type of operation.
+ * @filename:  Filename to check.
+ * @mode:      Access control mode.
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_check_single_path_permission2(struct tomoyo_domain_info *
+						const domain, u8 operation,
+						const struct tomoyo_path_info *
+						filename, const u8 mode)
+{
+	const char *msg;
+	int error;
+	const bool is_enforce = (mode == 3);
+
+	if (!mode)
+		return 0;
+ next:
+	error = tomoyo_check_single_path_acl(domain, operation, filename);
+	msg = tomoyo_sp2keyword(operation);
+	if (!error)
+		goto ok;
+	if (tomoyo_verbose_mode(domain))
+		printk(KERN_WARNING "TOMOYO-%s: Access '%s %s' denied for %s\n",
+		       tomoyo_get_msg(is_enforce), msg, filename->name,
+		       tomoyo_get_last_name(domain));
+	if (mode == 1 && tomoyo_domain_quota_is_ok(domain)) {
+		const char *name = tomoyo_get_file_pattern(filename)->name;
+		tomoyo_update_single_path_acl(operation, name, domain, false);
+	}
+	if (!is_enforce)
+		error = 0;
+ ok:
+	/*
+	 * Since "allow_truncate" doesn't imply "allow_rewrite" permission,
+	 * we need to check "allow_rewrite" permission if the filename is
+	 * specified by "deny_rewrite" keyword.
+	 */
+	if (!error && operation == TOMOYO_TYPE_TRUNCATE_ACL &&
+	    tomoyo_is_no_rewrite_file(filename)) {
+		operation = TOMOYO_TYPE_REWRITE_ACL;
+		goto next;
+	}
+	return error;
+}
+
+/**
+ * tomoyo_check_file_perm - Check permission for sysctl()'s "read" and "write".
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @filename:  Filename to check.
+ * @perm:      Mode ("read" or "write" or "read/write").
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_check_file_perm(struct tomoyo_domain_info *domain,
+			   const char *filename, const u8 perm)
+{
+	struct tomoyo_path_info name;
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+
+	if (!mode)
+		return 0;
+	name.name = filename;
+	tomoyo_fill_path_info(&name);
+	return tomoyo_check_file_perm2(domain, &name, perm, "sysctl", mode);
+}
+
+/**
+ * tomoyo_check_exec_perm - Check permission for "execute".
+ *
+ * @domain:   Pointer to "struct tomoyo_domain_info".
+ * @filename: Check permission for "execute".
+ * @tmp:      Buffer for temporary use.
+ *
+ * Returns 0 on success, negativevalue otherwise.
+ */
+int tomoyo_check_exec_perm(struct tomoyo_domain_info *domain,
+			   const struct tomoyo_path_info *filename,
+			   struct tomoyo_page_buffer *tmp)
+{
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+
+	if (!mode)
+		return 0;
+	return tomoyo_check_file_perm2(domain, filename, 1, "do_execve", mode);
+}
+
+/**
+ * tomoyo_check_open_permission - Check permission for "read" and "write".
+ *
+ * @domain: Pointer to "struct tomoyo_domain_info".
+ * @path:   Pointer to "struct path".
+ * @flag:   Flags for open().
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_check_open_permission(struct tomoyo_domain_info *domain,
+				 struct path *path, const int flag)
+{
+	const u8 acc_mode = ACC_MODE(flag);
+	int error = -ENOMEM;
+	struct tomoyo_path_info *buf;
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+	const bool is_enforce = (mode == 3);
+
+	if (!mode || !path->mnt)
+		return 0;
+	if (acc_mode == 0)
+		return 0;
+	if (path->dentry->d_inode && S_ISDIR(path->dentry->d_inode->i_mode))
+		/*
+		 * I don't check directories here because mkdir() and rmdir()
+		 * don't call me.
+		 */
+		return 0;
+	buf = tomoyo_get_path(path);
+	if (!buf)
+		goto out;
+	error = 0;
+	/*
+	 * If the filename is specified by "deny_rewrite" keyword,
+	 * we need to check "allow_rewrite" permission when the filename is not
+	 * opened for append mode or the filename is truncated at open time.
+	 */
+	if ((acc_mode & MAY_WRITE) &&
+	    ((flag & O_TRUNC) || !(flag & O_APPEND)) &&
+	    (tomoyo_is_no_rewrite_file(buf))) {
+		error = tomoyo_check_single_path_permission2(domain,
+						     TOMOYO_TYPE_REWRITE_ACL,
+							     buf, mode);
+	}
+	if (!error)
+		error = tomoyo_check_file_perm2(domain, buf, acc_mode, "open",
+						mode);
+	if (!error && (flag & O_TRUNC))
+		error = tomoyo_check_single_path_permission2(domain,
+						     TOMOYO_TYPE_TRUNCATE_ACL,
+							     buf, mode);
+ out:
+	tomoyo_free(buf);
+	if (!is_enforce)
+		error = 0;
+	return error;
+}
+
+/**
+ * tomoyo_check_1path_perm - Check permission for "create", "unlink", "mkdir", "rmdir", "mkfifo", "mksock", "mkblock", "mkchar", "truncate" and "symlink".
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @operation: Type of operation.
+ * @path:      Pointer to "struct path".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_check_1path_perm(struct tomoyo_domain_info *domain,
+			    const u8 operation, struct path *path)
+{
+	int error = -ENOMEM;
+	struct tomoyo_path_info *buf;
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+	const bool is_enforce = (mode == 3);
+
+	if (!mode || !path->mnt)
+		return 0;
+	buf = tomoyo_get_path(path);
+	if (!buf)
+		goto out;
+	switch (operation) {
+	case TOMOYO_TYPE_MKDIR_ACL:
+	case TOMOYO_TYPE_RMDIR_ACL:
+		if (!buf->is_dir) {
+			/*
+			 * tomoyo_get_path() reserves space for appending "/."
+			 */
+			strcat((char *) buf->name, "/");
+			tomoyo_fill_path_info(buf);
+		}
+	}
+	error = tomoyo_check_single_path_permission2(domain, operation, buf,
+						     mode);
+ out:
+	tomoyo_free(buf);
+	if (!is_enforce)
+		error = 0;
+	return error;
+}
+
+/**
+ * tomoyo_check_rewrite_permission - Check permission for "rewrite".
+ *
+ * @domain: Pointer to "struct tomoyo_domain_info".
+ * @filp: Pointer to "struct file".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_check_rewrite_permission(struct tomoyo_domain_info *domain,
+				    struct file *filp)
+{
+	int error = -ENOMEM;
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+	const bool is_enforce = (mode == 3);
+	struct tomoyo_path_info *buf;
+
+	if (!mode || !filp->f_path.mnt)
+		return 0;
+	buf = tomoyo_get_path(&filp->f_path);
+	if (!buf)
+		goto out;
+	if (!tomoyo_is_no_rewrite_file(buf)) {
+		error = 0;
+		goto out;
+	}
+	error = tomoyo_check_single_path_permission2(domain,
+						     TOMOYO_TYPE_REWRITE_ACL,
+						     buf, mode);
+ out:
+	tomoyo_free(buf);
+	if (!is_enforce)
+		error = 0;
+	return error;
+}
+
+/**
+ * tomoyo_check_2path_perm - Check permission for "rename" and "link".
+ *
+ * @domain:    Pointer to "struct tomoyo_domain_info".
+ * @operation: Type of operation.
+ * @path1:      Pointer to "struct path".
+ * @path2:      Pointer to "struct path".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+int tomoyo_check_2path_perm(struct tomoyo_domain_info * const domain,
+			    const u8 operation, struct path *path1,
+			    struct path *path2)
+{
+	int error = -ENOMEM;
+	struct tomoyo_path_info *buf1, *buf2;
+	const u8 mode = tomoyo_check_flags(domain, TOMOYO_MAC_FOR_FILE);
+	const bool is_enforce = (mode == 3);
+	const char *msg;
+
+	if (!mode || !path1->mnt || !path2->mnt)
+		return 0;
+	buf1 = tomoyo_get_path(path1);
+	buf2 = tomoyo_get_path(path2);
+	if (!buf1 || !buf2)
+		goto out;
+	{
+		struct dentry *dentry = path1->dentry;
+		if (dentry->d_inode && S_ISDIR(dentry->d_inode->i_mode)) {
+			/*
+			 * tomoyo_get_path() reserves space for appending "/."
+			 */
+			if (!buf1->is_dir) {
+				strcat((char *) buf1->name, "/");
+				tomoyo_fill_path_info(buf1);
+			}
+			if (!buf2->is_dir) {
+				strcat((char *) buf2->name, "/");
+				tomoyo_fill_path_info(buf2);
+			}
+		}
+	}
+	error = tomoyo_check_double_path_acl(domain, operation, buf1, buf2);
+	msg = tomoyo_dp2keyword(operation);
+	if (!error)
+		goto out;
+	if (tomoyo_verbose_mode(domain))
+		printk(KERN_WARNING "TOMOYO-%s: Access '%s %s %s' "
+		       "denied for %s\n", tomoyo_get_msg(is_enforce),
+		       msg, buf1->name, buf2->name,
+		       tomoyo_get_last_name(domain));
+	if (mode == 1 && tomoyo_domain_quota_is_ok(domain)) {
+		const char *name1 = tomoyo_get_file_pattern(buf1)->name;
+		const char *name2 = tomoyo_get_file_pattern(buf2)->name;
+		tomoyo_update_double_path_acl(operation, name1, name2, domain,
+					      false);
+	}
+ out:
+	tomoyo_free(buf1);
+	tomoyo_free(buf2);
+	if (!is_enforce)
+		error = 0;
+	return error;
+}