[deliverable/linux.git] / security / tomoyo / file.c

/*
 * security/tomoyo/file.c
 *
 * Pathname restriction functions.
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 */

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

/* Keyword array for operations with one pathname. */
const char *tomoyo_path_keyword[TOMOYO_MAX_PATH_OPERATION] = {
        [TOMOYO_TYPE_READ_WRITE] = "read/write",
        [TOMOYO_TYPE_EXECUTE]    = "execute",
        [TOMOYO_TYPE_READ]       = "read",
        [TOMOYO_TYPE_WRITE]      = "write",
        [TOMOYO_TYPE_UNLINK]     = "unlink",
        [TOMOYO_TYPE_RMDIR]      = "rmdir",
        [TOMOYO_TYPE_TRUNCATE]   = "truncate",
        [TOMOYO_TYPE_SYMLINK]    = "symlink",
        [TOMOYO_TYPE_REWRITE]    = "rewrite",
        [TOMOYO_TYPE_CHROOT]     = "chroot",
        [TOMOYO_TYPE_UMOUNT]     = "unmount",
};

/* Keyword array for operations with one pathname and three numbers. */
const char *tomoyo_mkdev_keyword[TOMOYO_MAX_MKDEV_OPERATION] = {
        [TOMOYO_TYPE_MKBLOCK]    = "mkblock",
        [TOMOYO_TYPE_MKCHAR]     = "mkchar",
};

/* Keyword array for operations with two pathnames. */
const char *tomoyo_path2_keyword[TOMOYO_MAX_PATH2_OPERATION] = {
        [TOMOYO_TYPE_LINK]       = "link",
        [TOMOYO_TYPE_RENAME]     = "rename",
        [TOMOYO_TYPE_PIVOT_ROOT] = "pivot_root",
};

/* Keyword array for operations with one pathname and one number. */
const char *tomoyo_path_number_keyword[TOMOYO_MAX_PATH_NUMBER_OPERATION] = {
        [TOMOYO_TYPE_CREATE]     = "create",
        [TOMOYO_TYPE_MKDIR]      = "mkdir",
        [TOMOYO_TYPE_MKFIFO]     = "mkfifo",
        [TOMOYO_TYPE_MKSOCK]     = "mksock",
        [TOMOYO_TYPE_IOCTL]      = "ioctl",
        [TOMOYO_TYPE_CHMOD]      = "chmod",
        [TOMOYO_TYPE_CHOWN]      = "chown",
        [TOMOYO_TYPE_CHGRP]      = "chgrp",
};

static const u8 tomoyo_p2mac[TOMOYO_MAX_PATH_OPERATION] = {
        [TOMOYO_TYPE_READ_WRITE] = TOMOYO_MAC_FILE_OPEN,
        [TOMOYO_TYPE_EXECUTE]    = TOMOYO_MAC_FILE_EXECUTE,
        [TOMOYO_TYPE_READ]       = TOMOYO_MAC_FILE_OPEN,
        [TOMOYO_TYPE_WRITE]      = TOMOYO_MAC_FILE_OPEN,
        [TOMOYO_TYPE_UNLINK]     = TOMOYO_MAC_FILE_UNLINK,
        [TOMOYO_TYPE_RMDIR]      = TOMOYO_MAC_FILE_RMDIR,
        [TOMOYO_TYPE_TRUNCATE]   = TOMOYO_MAC_FILE_TRUNCATE,
        [TOMOYO_TYPE_SYMLINK]    = TOMOYO_MAC_FILE_SYMLINK,
        [TOMOYO_TYPE_REWRITE]    = TOMOYO_MAC_FILE_REWRITE,
        [TOMOYO_TYPE_CHROOT]     = TOMOYO_MAC_FILE_CHROOT,
        [TOMOYO_TYPE_UMOUNT]     = TOMOYO_MAC_FILE_UMOUNT,
};

static const u8 tomoyo_pnnn2mac[TOMOYO_MAX_MKDEV_OPERATION] = {
        [TOMOYO_TYPE_MKBLOCK] = TOMOYO_MAC_FILE_MKBLOCK,
        [TOMOYO_TYPE_MKCHAR]  = TOMOYO_MAC_FILE_MKCHAR,
};

static const u8 tomoyo_pp2mac[TOMOYO_MAX_PATH2_OPERATION] = {
        [TOMOYO_TYPE_LINK]       = TOMOYO_MAC_FILE_LINK,
        [TOMOYO_TYPE_RENAME]     = TOMOYO_MAC_FILE_RENAME,
        [TOMOYO_TYPE_PIVOT_ROOT] = TOMOYO_MAC_FILE_PIVOT_ROOT,
};

static const u8 tomoyo_pn2mac[TOMOYO_MAX_PATH_NUMBER_OPERATION] = {
        [TOMOYO_TYPE_CREATE] = TOMOYO_MAC_FILE_CREATE,
        [TOMOYO_TYPE_MKDIR]  = TOMOYO_MAC_FILE_MKDIR,
        [TOMOYO_TYPE_MKFIFO] = TOMOYO_MAC_FILE_MKFIFO,
        [TOMOYO_TYPE_MKSOCK] = TOMOYO_MAC_FILE_MKSOCK,
        [TOMOYO_TYPE_IOCTL]  = TOMOYO_MAC_FILE_IOCTL,
        [TOMOYO_TYPE_CHMOD]  = TOMOYO_MAC_FILE_CHMOD,
        [TOMOYO_TYPE_CHOWN]  = TOMOYO_MAC_FILE_CHOWN,
        [TOMOYO_TYPE_CHGRP]  = TOMOYO_MAC_FILE_CHGRP,
};

void tomoyo_put_name_union(struct tomoyo_name_union *ptr)
{
        if (!ptr)
                return;
        if (ptr->is_group)
                tomoyo_put_group(ptr->group);
        else
                tomoyo_put_name(ptr->filename);
}

bool tomoyo_compare_name_union(const struct tomoyo_path_info *name,
                               const struct tomoyo_name_union *ptr)
{
        if (ptr->is_group)
                return tomoyo_path_matches_group(name, ptr->group);
        return tomoyo_path_matches_pattern(name, ptr->filename);
}

void tomoyo_put_number_union(struct tomoyo_number_union *ptr)
{
        if (ptr && ptr->is_group)
                tomoyo_put_group(ptr->group);
}

bool tomoyo_compare_number_union(const unsigned long value,
                                 const struct tomoyo_number_union *ptr)
{
        if (ptr->is_group)
                return tomoyo_number_matches_group(value, value, ptr->group);
        return value >= ptr->values[0] && value <= ptr->values[1];
}

static void tomoyo_add_slash(struct tomoyo_path_info *buf)
{
        if (buf->is_dir)
                return;
        /*
         * This is OK because tomoyo_encode() reserves space for appending "/".
         */
        strcat((char *) buf->name, "/");
        tomoyo_fill_path_info(buf);
}

/**
 * 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_realpath - Get realpath.
 *
 * @buf:  Pointer to "struct tomoyo_path_info".
 * @path: Pointer to "struct path".
 *
 * Returns true on success, false otherwise.
 */
static bool tomoyo_get_realpath(struct tomoyo_path_info *buf, struct path *path)
{
        buf->name = tomoyo_realpath_from_path(path);
        if (buf->name) {
                tomoyo_fill_path_info(buf);
                return true;
        }
        return false;
}

/**
 * tomoyo_audit_path_log - Audit path request log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_path_log(struct tomoyo_request_info *r)
{
        const char *operation = tomoyo_path_keyword[r->param.path.operation];
        const struct tomoyo_path_info *filename = r->param.path.filename;
        if (r->granted)
                return 0;
        tomoyo_warn_log(r, "%s %s", operation, filename->name);
        return tomoyo_supervisor(r, "allow_%s %s\n", operation,
                                 tomoyo_pattern(filename));
}

/**
 * tomoyo_audit_path2_log - Audit path/path request log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_path2_log(struct tomoyo_request_info *r)
{
        const char *operation = tomoyo_path2_keyword[r->param.path2.operation];
        const struct tomoyo_path_info *filename1 = r->param.path2.filename1;
        const struct tomoyo_path_info *filename2 = r->param.path2.filename2;
        if (r->granted)
                return 0;
        tomoyo_warn_log(r, "%s %s %s", operation, filename1->name,
                        filename2->name);
        return tomoyo_supervisor(r, "allow_%s %s %s\n", operation,
                                 tomoyo_pattern(filename1),
                                 tomoyo_pattern(filename2));
}

/**
 * tomoyo_audit_mkdev_log - Audit path/number/number/number request log.
 *
 * @r: Pointer to "struct tomoyo_request_info".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_mkdev_log(struct tomoyo_request_info *r)
{
        const char *operation = tomoyo_mkdev_keyword[r->param.mkdev.operation];
        const struct tomoyo_path_info *filename = r->param.mkdev.filename;
        const unsigned int major = r->param.mkdev.major;
        const unsigned int minor = r->param.mkdev.minor;
        const unsigned int mode = r->param.mkdev.mode;
        if (r->granted)
                return 0;
        tomoyo_warn_log(r, "%s %s 0%o %u %u", operation, filename->name, mode,
                        major, minor);
        return tomoyo_supervisor(r, "allow_%s %s 0%o %u %u\n", operation,
                                 tomoyo_pattern(filename), mode, major, minor);
}

/**
 * tomoyo_audit_path_number_log - Audit path/number request log.
 *
 * @r:     Pointer to "struct tomoyo_request_info".
 * @error: Error code.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int tomoyo_audit_path_number_log(struct tomoyo_request_info *r)
{
        const u8 type = r->param.path_number.operation;
        u8 radix;
        const struct tomoyo_path_info *filename = r->param.path_number.filename;
        const char *operation = tomoyo_path_number_keyword[type];
        char buffer[64];
        if (r->granted)
                return 0;
        switch (type) {
        case TOMOYO_TYPE_CREATE:
        case TOMOYO_TYPE_MKDIR:
        case TOMOYO_TYPE_MKFIFO:
        case TOMOYO_TYPE_MKSOCK:
        case TOMOYO_TYPE_CHMOD:
                radix = TOMOYO_VALUE_TYPE_OCTAL;
                break;
        case TOMOYO_TYPE_IOCTL:
                radix = TOMOYO_VALUE_TYPE_HEXADECIMAL;
                break;
        default:
                radix = TOMOYO_VALUE_TYPE_DECIMAL;
                break;
        }
        tomoyo_print_ulong(buffer, sizeof(buffer), r->param.path_number.number,
                           radix);
        tomoyo_warn_log(r, "%s %s %s", operation, filename->name, buffer);
        return tomoyo_supervisor(r, "allow_%s %s %s\n", operation,
                                 tomoyo_pattern(filename), buffer);
}

static bool tomoyo_same_globally_readable(const struct tomoyo_acl_head *a,
                                          const struct tomoyo_acl_head *b)
{
        return container_of(a, struct tomoyo_readable_file,
                            head)->filename ==
                container_of(b, struct tomoyo_readable_file,
                             head)->filename;
}

/**
 * tomoyo_update_globally_readable_entry - Update "struct tomoyo_readable_file" 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.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_globally_readable_entry(const char *filename,
                                                 const bool is_delete)
{
        struct tomoyo_readable_file e = { };
        int error;

        if (!tomoyo_correct_word(filename))
                return -EINVAL;
        e.filename = tomoyo_get_name(filename);
        if (!e.filename)
                return -ENOMEM;
        error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
                                     &tomoyo_policy_list
                                     [TOMOYO_ID_GLOBALLY_READABLE],
                                     tomoyo_same_globally_readable);
        tomoyo_put_name(e.filename);
        return error;
}

/**
 * tomoyo_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.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_globally_readable_file(const struct tomoyo_path_info *
                                             filename)
{
        struct tomoyo_readable_file *ptr;
        bool found = false;

        list_for_each_entry_rcu(ptr, &tomoyo_policy_list
                                [TOMOYO_ID_GLOBALLY_READABLE], head.list) {
                if (!ptr->head.is_deleted &&
                    tomoyo_path_matches_pattern(filename, ptr->filename)) {
                        found = true;
                        break;
                }
        }
        return found;
}

/**
 * tomoyo_write_globally_readable - Write "struct tomoyo_readable_file" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_write_globally_readable(char *data, const bool is_delete)
{
        return tomoyo_update_globally_readable_entry(data, is_delete);
}

static bool tomoyo_same_pattern(const struct tomoyo_acl_head *a,
                                const struct tomoyo_acl_head *b)
{
        return container_of(a, struct tomoyo_no_pattern, head)->pattern ==
                container_of(b, struct tomoyo_no_pattern, head)->pattern;
}

/**
 * tomoyo_update_file_pattern_entry - Update "struct tomoyo_no_pattern" list.
 *
 * @pattern:   Pathname pattern.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_file_pattern_entry(const char *pattern,
                                            const bool is_delete)
{
        struct tomoyo_no_pattern e = { };
        int error;

        if (!tomoyo_correct_word(pattern))
                return -EINVAL;
        e.pattern = tomoyo_get_name(pattern);
        if (!e.pattern)
                return -ENOMEM;
        error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
                                     &tomoyo_policy_list[TOMOYO_ID_PATTERN],
                                     tomoyo_same_pattern);
        tomoyo_put_name(e.pattern);
        return error;
}

/**
 * tomoyo_pattern - Get patterned pathname.
 *
 * @filename: The filename to find patterned pathname.
 *
 * Returns pointer to pathname pattern if matched, @filename otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
const char *tomoyo_pattern(const struct tomoyo_path_info *filename)
{
        struct tomoyo_no_pattern *ptr;
        const struct tomoyo_path_info *pattern = NULL;

        list_for_each_entry_rcu(ptr, &tomoyo_policy_list[TOMOYO_ID_PATTERN],
                                head.list) {
                if (ptr->head.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;
                }
        }
        if (pattern)
                filename = pattern;
        return filename->name;
}

/**
 * tomoyo_write_pattern - Write "struct tomoyo_no_pattern" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_write_pattern(char *data, const bool is_delete)
{
        return tomoyo_update_file_pattern_entry(data, is_delete);
}

static bool tomoyo_same_no_rewrite(const struct tomoyo_acl_head *a,
                                   const struct tomoyo_acl_head *b)
{
        return container_of(a, struct tomoyo_no_rewrite, head)->pattern
                == container_of(b, struct tomoyo_no_rewrite, head)
                ->pattern;
}

/**
 * tomoyo_update_no_rewrite_entry - Update "struct tomoyo_no_rewrite" 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.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_no_rewrite_entry(const char *pattern,
                                          const bool is_delete)
{
        struct tomoyo_no_rewrite e = { };
        int error;

        if (!tomoyo_correct_word(pattern))
                return -EINVAL;
        e.pattern = tomoyo_get_name(pattern);
        if (!e.pattern)
                return -ENOMEM;
        error = tomoyo_update_policy(&e.head, sizeof(e), is_delete,
                                     &tomoyo_policy_list[TOMOYO_ID_NO_REWRITE],
                                     tomoyo_same_no_rewrite);
        tomoyo_put_name(e.pattern);
        return error;
}

/**
 * tomoyo_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.
 *
 * Caller holds tomoyo_read_lock().
 */
static bool tomoyo_no_rewrite_file(const struct tomoyo_path_info *filename)
{
        struct tomoyo_no_rewrite *ptr;
        bool found = false;

        list_for_each_entry_rcu(ptr, &tomoyo_policy_list[TOMOYO_ID_NO_REWRITE],
                                head.list) {
                if (ptr->head.is_deleted)
                        continue;
                if (!tomoyo_path_matches_pattern(filename, ptr->pattern))
                        continue;
                found = true;
                break;
        }
        return found;
}

/**
 * tomoyo_write_no_rewrite - Write "struct tomoyo_no_rewrite" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_write_no_rewrite(char *data, const bool is_delete)
{
        return tomoyo_update_no_rewrite_entry(data, is_delete);
}

static bool tomoyo_check_path_acl(const struct tomoyo_request_info *r,
                                  const struct tomoyo_acl_info *ptr)
{
        const struct tomoyo_path_acl *acl = container_of(ptr, typeof(*acl),
                                                         head);
        return (acl->perm & (1 << r->param.path.operation)) &&
                tomoyo_compare_name_union(r->param.path.filename, &acl->name);
}

static bool tomoyo_check_path_number_acl(const struct tomoyo_request_info *r,
                                         const struct tomoyo_acl_info *ptr)
{
        const struct tomoyo_path_number_acl *acl =
                container_of(ptr, typeof(*acl), head);
        return (acl->perm & (1 << r->param.path_number.operation)) &&
                tomoyo_compare_number_union(r->param.path_number.number,
                                            &acl->number) &&
                tomoyo_compare_name_union(r->param.path_number.filename,
                                          &acl->name);
}

static bool tomoyo_check_path2_acl(const struct tomoyo_request_info *r,
                                   const struct tomoyo_acl_info *ptr)
{
        const struct tomoyo_path2_acl *acl =
                container_of(ptr, typeof(*acl), head);
        return (acl->perm & (1 << r->param.path2.operation)) &&
                tomoyo_compare_name_union(r->param.path2.filename1, &acl->name1)
                && tomoyo_compare_name_union(r->param.path2.filename2,
                                             &acl->name2);
}

static bool tomoyo_check_mkdev_acl(const struct tomoyo_request_info *r,
                                const struct tomoyo_acl_info *ptr)
{
        const struct tomoyo_mkdev_acl *acl =
                container_of(ptr, typeof(*acl), head);
        return (acl->perm & (1 << r->param.mkdev.operation)) &&
                tomoyo_compare_number_union(r->param.mkdev.mode,
                                            &acl->mode) &&
                tomoyo_compare_number_union(r->param.mkdev.major,
                                            &acl->major) &&
                tomoyo_compare_number_union(r->param.mkdev.minor,
                                            &acl->minor) &&
                tomoyo_compare_name_union(r->param.mkdev.filename,
                                          &acl->name);
}

static bool tomoyo_same_path_acl(const struct tomoyo_acl_info *a,
                                 const struct tomoyo_acl_info *b)
{
        const struct tomoyo_path_acl *p1 = container_of(a, typeof(*p1), head);
        const struct tomoyo_path_acl *p2 = container_of(b, typeof(*p2), head);
        return tomoyo_same_acl_head(&p1->head, &p2->head) &&
                tomoyo_same_name_union(&p1->name, &p2->name);
}

static bool tomoyo_merge_path_acl(struct tomoyo_acl_info *a,
                                  struct tomoyo_acl_info *b,
                                  const bool is_delete)
{
        u16 * const a_perm = &container_of(a, struct tomoyo_path_acl, head)
                ->perm;
        u16 perm = *a_perm;
        const u16 b_perm = container_of(b, struct tomoyo_path_acl, head)->perm;
        if (is_delete) {
                perm &= ~b_perm;
                if ((perm & TOMOYO_RW_MASK) != TOMOYO_RW_MASK)
                        perm &= ~(1 << TOMOYO_TYPE_READ_WRITE);
                else if (!(perm & (1 << TOMOYO_TYPE_READ_WRITE)))
                        perm &= ~TOMOYO_RW_MASK;
        } else {
                perm |= b_perm;
                if ((perm & TOMOYO_RW_MASK) == TOMOYO_RW_MASK)
                        perm |= (1 << TOMOYO_TYPE_READ_WRITE);
                else if (perm & (1 << TOMOYO_TYPE_READ_WRITE))
                        perm |= TOMOYO_RW_MASK;
        }
        *a_perm = perm;
        return !perm;
}

/**
 * tomoyo_update_path_acl - Update "struct tomoyo_path_acl" 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.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_path_acl(const u8 type, const char *filename,
                                  struct tomoyo_domain_info * const domain,
                                  const bool is_delete)
{
        struct tomoyo_path_acl e = {
                .head.type = TOMOYO_TYPE_PATH_ACL,
                .perm = 1 << type
        };
        int error;
        if (e.perm == (1 << TOMOYO_TYPE_READ_WRITE))
                e.perm |= TOMOYO_RW_MASK;
        if (!tomoyo_parse_name_union(filename, &e.name))
                return -EINVAL;
        error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
                                     tomoyo_same_path_acl,
                                     tomoyo_merge_path_acl);
        tomoyo_put_name_union(&e.name);
        return error;
}

static bool tomoyo_same_mkdev_acl(const struct tomoyo_acl_info *a,
                                         const struct tomoyo_acl_info *b)
{
        const struct tomoyo_mkdev_acl *p1 = container_of(a, typeof(*p1),
                                                                head);
        const struct tomoyo_mkdev_acl *p2 = container_of(b, typeof(*p2),
                                                                head);
        return tomoyo_same_acl_head(&p1->head, &p2->head)
                && tomoyo_same_name_union(&p1->name, &p2->name)
                && tomoyo_same_number_union(&p1->mode, &p2->mode)
                && tomoyo_same_number_union(&p1->major, &p2->major)
                && tomoyo_same_number_union(&p1->minor, &p2->minor);
}

static bool tomoyo_merge_mkdev_acl(struct tomoyo_acl_info *a,
                                          struct tomoyo_acl_info *b,
                                          const bool is_delete)
{
        u8 *const a_perm = &container_of(a, struct tomoyo_mkdev_acl,
                                         head)->perm;
        u8 perm = *a_perm;
        const u8 b_perm = container_of(b, struct tomoyo_mkdev_acl, head)
                ->perm;
        if (is_delete)
                perm &= ~b_perm;
        else
                perm |= b_perm;
        *a_perm = perm;
        return !perm;
}

/**
 * tomoyo_update_mkdev_acl - Update "struct tomoyo_mkdev_acl" list.
 *
 * @type:      Type of operation.
 * @filename:  Filename.
 * @mode:      Create mode.
 * @major:     Device major number.
 * @minor:     Device minor number.
 * @domain:    Pointer to "struct tomoyo_domain_info".
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_mkdev_acl(const u8 type, const char *filename,
                                          char *mode, char *major, char *minor,
                                          struct tomoyo_domain_info * const
                                          domain, const bool is_delete)
{
        struct tomoyo_mkdev_acl e = {
                .head.type = TOMOYO_TYPE_MKDEV_ACL,
                .perm = 1 << type
        };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (!tomoyo_parse_name_union(filename, &e.name) ||
            !tomoyo_parse_number_union(mode, &e.mode) ||
            !tomoyo_parse_number_union(major, &e.major) ||
            !tomoyo_parse_number_union(minor, &e.minor))
                goto out;
        error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
                                     tomoyo_same_mkdev_acl,
                                     tomoyo_merge_mkdev_acl);
 out:
        tomoyo_put_name_union(&e.name);
        tomoyo_put_number_union(&e.mode);
        tomoyo_put_number_union(&e.major);
        tomoyo_put_number_union(&e.minor);
        return error;
}

static bool tomoyo_same_path2_acl(const struct tomoyo_acl_info *a,
                                  const struct tomoyo_acl_info *b)
{
        const struct tomoyo_path2_acl *p1 = container_of(a, typeof(*p1), head);
        const struct tomoyo_path2_acl *p2 = container_of(b, typeof(*p2), head);
        return tomoyo_same_acl_head(&p1->head, &p2->head)
                && tomoyo_same_name_union(&p1->name1, &p2->name1)
                && tomoyo_same_name_union(&p1->name2, &p2->name2);
}

static bool tomoyo_merge_path2_acl(struct tomoyo_acl_info *a,
                                   struct tomoyo_acl_info *b,
                                   const bool is_delete)
{
        u8 * const a_perm = &container_of(a, struct tomoyo_path2_acl, head)
                ->perm;
        u8 perm = *a_perm;
        const u8 b_perm = container_of(b, struct tomoyo_path2_acl, head)->perm;
        if (is_delete)
                perm &= ~b_perm;
        else
                perm |= b_perm;
        *a_perm = perm;
        return !perm;
}

/**
 * tomoyo_update_path2_acl - Update "struct tomoyo_path2_acl" 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.
 *
 * Caller holds tomoyo_read_lock().
 */
static int tomoyo_update_path2_acl(const u8 type, const char *filename1,
                                   const char *filename2,
                                   struct tomoyo_domain_info * const domain,
                                   const bool is_delete)
{
        struct tomoyo_path2_acl e = {
                .head.type = TOMOYO_TYPE_PATH2_ACL,
                .perm = 1 << type
        };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (!tomoyo_parse_name_union(filename1, &e.name1) ||
            !tomoyo_parse_name_union(filename2, &e.name2))
                goto out;
        error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
                                     tomoyo_same_path2_acl,
                                     tomoyo_merge_path2_acl);
 out:
        tomoyo_put_name_union(&e.name1);
        tomoyo_put_name_union(&e.name2);
        return error;
}

/**
 * tomoyo_path_permission - Check permission for single path operation.
 *
 * @r:         Pointer to "struct tomoyo_request_info".
 * @operation: Type of operation.
 * @filename:  Filename to check.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_path_permission(struct tomoyo_request_info *r, u8 operation,
                           const struct tomoyo_path_info *filename)
{
        int error;

 next:
        r->type = tomoyo_p2mac[operation];
        r->mode = tomoyo_get_mode(r->profile, r->type);
        if (r->mode == TOMOYO_CONFIG_DISABLED)
                return 0;
        r->param_type = TOMOYO_TYPE_PATH_ACL;
        r->param.path.filename = filename;
        r->param.path.operation = operation;
        do {
                tomoyo_check_acl(r, tomoyo_check_path_acl);
                if (!r->granted && operation == TOMOYO_TYPE_READ &&
                    !r->domain->ignore_global_allow_read &&
                    tomoyo_globally_readable_file(filename))
                        r->granted = true;
                error = tomoyo_audit_path_log(r);
                /*
                 * Do not retry for execute request, for alias may have
                 * changed.
                 */
        } while (error == TOMOYO_RETRY_REQUEST &&
                 operation != TOMOYO_TYPE_EXECUTE);
        /*
         * 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 &&
            tomoyo_no_rewrite_file(filename)) {
                operation = TOMOYO_TYPE_REWRITE;
                goto next;
        }
        return error;
}

static bool tomoyo_same_path_number_acl(const struct tomoyo_acl_info *a,
                                        const struct tomoyo_acl_info *b)
{
        const struct tomoyo_path_number_acl *p1 = container_of(a, typeof(*p1),
                                                               head);
        const struct tomoyo_path_number_acl *p2 = container_of(b, typeof(*p2),
                                                               head);
        return tomoyo_same_acl_head(&p1->head, &p2->head)
                && tomoyo_same_name_union(&p1->name, &p2->name)
                && tomoyo_same_number_union(&p1->number, &p2->number);
}

static bool tomoyo_merge_path_number_acl(struct tomoyo_acl_info *a,
                                         struct tomoyo_acl_info *b,
                                         const bool is_delete)
{
        u8 * const a_perm = &container_of(a, struct tomoyo_path_number_acl,
                                          head)->perm;
        u8 perm = *a_perm;
        const u8 b_perm = container_of(b, struct tomoyo_path_number_acl, head)
                ->perm;
        if (is_delete)
                perm &= ~b_perm;
        else
                perm |= b_perm;
        *a_perm = perm;
        return !perm;
}

/**
 * tomoyo_update_path_number_acl - Update ioctl/chmod/chown/chgrp ACL.
 *
 * @type:      Type of operation.
 * @filename:  Filename.
 * @number:    Number.
 * @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_path_number_acl(const u8 type, const char *filename,
                                         char *number,
                                         struct tomoyo_domain_info * const
                                         domain,
                                         const bool is_delete)
{
        struct tomoyo_path_number_acl e = {
                .head.type = TOMOYO_TYPE_PATH_NUMBER_ACL,
                .perm = 1 << type
        };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (!tomoyo_parse_name_union(filename, &e.name))
                return -EINVAL;
        if (!tomoyo_parse_number_union(number, &e.number))
                goto out;
        error = tomoyo_update_domain(&e.head, sizeof(e), is_delete, domain,
                                     tomoyo_same_path_number_acl,
                                     tomoyo_merge_path_number_acl);
 out:
        tomoyo_put_name_union(&e.name);
        tomoyo_put_number_union(&e.number);
        return error;
}

/**
 * tomoyo_path_number_perm - Check permission for "create", "mkdir", "mkfifo", "mksock", "ioctl", "chmod", "chown", "chgrp".
 *
 * @type:   Type of operation.
 * @path:   Pointer to "struct path".
 * @number: Number.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_path_number_perm(const u8 type, struct path *path,
                            unsigned long number)
{
        struct tomoyo_request_info r;
        int error = -ENOMEM;
        struct tomoyo_path_info buf;
        int idx;

        if (tomoyo_init_request_info(&r, NULL, tomoyo_pn2mac[type])
            == TOMOYO_CONFIG_DISABLED || !path->mnt || !path->dentry)
                return 0;
        idx = tomoyo_read_lock();
        if (!tomoyo_get_realpath(&buf, path))
                goto out;
        if (type == TOMOYO_TYPE_MKDIR)
                tomoyo_add_slash(&buf);
        r.param_type = TOMOYO_TYPE_PATH_NUMBER_ACL;
        r.param.path_number.operation = type;
        r.param.path_number.filename = &buf;
        r.param.path_number.number = number;
        do {
                tomoyo_check_acl(&r, tomoyo_check_path_number_acl);
                error = tomoyo_audit_path_number_log(&r);
        } while (error == TOMOYO_RETRY_REQUEST);
        kfree(buf.name);
 out:
        tomoyo_read_unlock(idx);
        if (r.mode != TOMOYO_CONFIG_ENFORCING)
                error = 0;
        return error;
}

/**
 * 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;
        struct tomoyo_request_info r;
        int idx;

        if (!path->mnt ||
            (path->dentry->d_inode && S_ISDIR(path->dentry->d_inode->i_mode)))
                return 0;
        buf.name = NULL;
        r.mode = TOMOYO_CONFIG_DISABLED;
        idx = tomoyo_read_lock();
        if (!tomoyo_get_realpath(&buf, path))
                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_APPEND)
            && tomoyo_init_request_info(&r, domain, TOMOYO_MAC_FILE_REWRITE)
            != TOMOYO_CONFIG_DISABLED) {
                if (!tomoyo_get_realpath(&buf, path)) {
                        error = -ENOMEM;
                        goto out;
                }
                if (tomoyo_no_rewrite_file(&buf))
                        error = tomoyo_path_permission(&r, TOMOYO_TYPE_REWRITE,
                                                       &buf);
        }
        if (!error && acc_mode &&
            tomoyo_init_request_info(&r, domain, TOMOYO_MAC_FILE_OPEN)
            != TOMOYO_CONFIG_DISABLED) {
                u8 operation;
                if (!buf.name && !tomoyo_get_realpath(&buf, path)) {
                        error = -ENOMEM;
                        goto out;
                }
                if (acc_mode == (MAY_READ | MAY_WRITE))
                        operation = TOMOYO_TYPE_READ_WRITE;
                else if (acc_mode == MAY_READ)
                        operation = TOMOYO_TYPE_READ;
                else
                        operation = TOMOYO_TYPE_WRITE;
                error = tomoyo_path_permission(&r, operation, &buf);
        }
 out:
        kfree(buf.name);
        tomoyo_read_unlock(idx);
        if (r.mode != TOMOYO_CONFIG_ENFORCING)
                error = 0;
        return error;
}

/**
 * tomoyo_path_perm - Check permission for "unlink", "rmdir", "truncate", "symlink", "rewrite", "chroot" and "unmount".
 *
 * @operation: Type of operation.
 * @path:      Pointer to "struct path".
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_path_perm(const u8 operation, struct path *path)
{
        int error = -ENOMEM;
        struct tomoyo_path_info buf;
        struct tomoyo_request_info r;
        int idx;

        if (!path->mnt)
                return 0;
        if (tomoyo_init_request_info(&r, NULL, tomoyo_p2mac[operation])
            == TOMOYO_CONFIG_DISABLED)
                return 0;
        buf.name = NULL;
        idx = tomoyo_read_lock();
        if (!tomoyo_get_realpath(&buf, path))
                goto out;
        switch (operation) {
        case TOMOYO_TYPE_REWRITE:
                if (!tomoyo_no_rewrite_file(&buf)) {
                        error = 0;
                        goto out;
                }
                break;
        case TOMOYO_TYPE_RMDIR:
        case TOMOYO_TYPE_CHROOT:
        case TOMOYO_TYPE_UMOUNT:
                tomoyo_add_slash(&buf);
                break;
        }
        error = tomoyo_path_permission(&r, operation, &buf);
 out:
        kfree(buf.name);
        tomoyo_read_unlock(idx);
        if (r.mode != TOMOYO_CONFIG_ENFORCING)
                error = 0;
        return error;
}

/**
 * tomoyo_mkdev_perm - Check permission for "mkblock" and "mkchar".
 *
 * @operation: Type of operation. (TOMOYO_TYPE_MKCHAR or TOMOYO_TYPE_MKBLOCK)
 * @path:      Pointer to "struct path".
 * @mode:      Create mode.
 * @dev:       Device number.
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_mkdev_perm(const u8 operation, struct path *path,
                             const unsigned int mode, unsigned int dev)
{
        struct tomoyo_request_info r;
        int error = -ENOMEM;
        struct tomoyo_path_info buf;
        int idx;

        if (!path->mnt ||
            tomoyo_init_request_info(&r, NULL, tomoyo_pnnn2mac[operation])
            == TOMOYO_CONFIG_DISABLED)
                return 0;
        idx = tomoyo_read_lock();
        error = -ENOMEM;
        if (tomoyo_get_realpath(&buf, path)) {
                dev = new_decode_dev(dev);
                r.param_type = TOMOYO_TYPE_MKDEV_ACL;
                r.param.mkdev.filename = &buf;
                r.param.mkdev.operation = operation;
                r.param.mkdev.mode = mode;
                r.param.mkdev.major = MAJOR(dev);
                r.param.mkdev.minor = MINOR(dev);
                tomoyo_check_acl(&r, tomoyo_check_mkdev_acl);
                error = tomoyo_audit_mkdev_log(&r);
                kfree(buf.name);
        }
        tomoyo_read_unlock(idx);
        if (r.mode != TOMOYO_CONFIG_ENFORCING)
                error = 0;
        return error;
}

/**
 * tomoyo_path2_perm - Check permission for "rename", "link" and "pivot_root".
 *
 * @operation: Type of operation.
 * @path1:      Pointer to "struct path".
 * @path2:      Pointer to "struct path".
 *
 * Returns 0 on success, negative value otherwise.
 */
int tomoyo_path2_perm(const u8 operation, struct path *path1,
                      struct path *path2)
{
        int error = -ENOMEM;
        struct tomoyo_path_info buf1;
        struct tomoyo_path_info buf2;
        struct tomoyo_request_info r;
        int idx;

        if (!path1->mnt || !path2->mnt ||
            tomoyo_init_request_info(&r, NULL, tomoyo_pp2mac[operation])
            == TOMOYO_CONFIG_DISABLED)
                return 0;
        buf1.name = NULL;
        buf2.name = NULL;
        idx = tomoyo_read_lock();
        if (!tomoyo_get_realpath(&buf1, path1) ||
            !tomoyo_get_realpath(&buf2, path2))
                goto out;
        switch (operation) {
                struct dentry *dentry;
        case TOMOYO_TYPE_RENAME:
        case TOMOYO_TYPE_LINK:
                dentry = path1->dentry;
                if (!dentry->d_inode || !S_ISDIR(dentry->d_inode->i_mode))
                        break;
                /* fall through */
        case TOMOYO_TYPE_PIVOT_ROOT:
                tomoyo_add_slash(&buf1);
                tomoyo_add_slash(&buf2);
                break;
        }
        r.param_type = TOMOYO_TYPE_PATH2_ACL;
        r.param.path2.operation = operation;
        r.param.path2.filename1 = &buf1;
        r.param.path2.filename2 = &buf2;
        do {
                tomoyo_check_acl(&r, tomoyo_check_path2_acl);
                error = tomoyo_audit_path2_log(&r);
        } while (error == TOMOYO_RETRY_REQUEST);
 out:
        kfree(buf1.name);
        kfree(buf2.name);
        tomoyo_read_unlock(idx);
        if (r.mode != TOMOYO_CONFIG_ENFORCING)
                error = 0;
        return error;
}

/**
 * tomoyo_write_file - 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.
 *
 * Caller holds tomoyo_read_lock().
 */
int tomoyo_write_file(char *data, struct tomoyo_domain_info *domain,
                      const bool is_delete)
{
        char *w[5];
        u8 type;
        if (!tomoyo_tokenize(data, w, sizeof(w)) || !w[1][0])
                return -EINVAL;
        if (strncmp(w[0], "allow_", 6))
                goto out;
        w[0] += 6;
        for (type = 0; type < TOMOYO_MAX_PATH_OPERATION; type++) {
                if (strcmp(w[0], tomoyo_path_keyword[type]))
                        continue;
                return tomoyo_update_path_acl(type, w[1], domain, is_delete);
        }
        if (!w[2][0])
                goto out;
        for (type = 0; type < TOMOYO_MAX_PATH2_OPERATION; type++) {
                if (strcmp(w[0], tomoyo_path2_keyword[type]))
                        continue;
                return tomoyo_update_path2_acl(type, w[1], w[2], domain,
                                               is_delete);
        }
        for (type = 0; type < TOMOYO_MAX_PATH_NUMBER_OPERATION; type++) {
                if (strcmp(w[0], tomoyo_path_number_keyword[type]))
                        continue;
                return tomoyo_update_path_number_acl(type, w[1], w[2], domain,
                                                     is_delete);
        }
        if (!w[3][0] || !w[4][0])
                goto out;
        for (type = 0; type < TOMOYO_MAX_MKDEV_OPERATION; type++) {
                if (strcmp(w[0], tomoyo_mkdev_keyword[type]))
                        continue;
                return tomoyo_update_mkdev_acl(type, w[1], w[2], w[3],
                                               w[4], domain, is_delete);
        }
 out:
        return -EINVAL;
}