path: root/security/tomoyo/common.h

/*
 * security/tomoyo/common.h
 *
 * Header file for TOMOYO.
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 */

#ifndef _SECURITY_TOMOYO_COMMON_H
#define _SECURITY_TOMOYO_COMMON_H

#include <linux/ctype.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/file.h>
#include <linux/kmod.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/list.h>
#include <linux/cred.h>
struct linux_binprm;

/********** Constants definitions. **********/

/*
 * TOMOYO uses this hash only when appending a string into the string
 * table. Frequency of appending strings is very low. So we don't need
 * large (e.g. 64k) hash size. 256 will be sufficient.
 */
#define TOMOYO_HASH_BITS  8
#define TOMOYO_MAX_HASH (1u<<TOMOYO_HASH_BITS)

/*
 * This is the max length of a token.
 *
 * A token consists of only ASCII printable characters.
 * Non printable characters in a token is represented in \ooo style
 * octal string. Thus, \ itself is represented as \\.
 */
#define TOMOYO_MAX_PATHNAME_LEN 4000

/* Profile number is an integer between 0 and 255. */
#define TOMOYO_MAX_PROFILES 256

/* Keywords for ACLs. */
#define TOMOYO_KEYWORD_ALIAS                     "alias "
#define TOMOYO_KEYWORD_ALLOW_READ                "allow_read "
#define TOMOYO_KEYWORD_DELETE                    "delete "
#define TOMOYO_KEYWORD_DENY_REWRITE              "deny_rewrite "
#define TOMOYO_KEYWORD_FILE_PATTERN              "file_pattern "
#define TOMOYO_KEYWORD_INITIALIZE_DOMAIN         "initialize_domain "
#define TOMOYO_KEYWORD_KEEP_DOMAIN               "keep_domain "
#define TOMOYO_KEYWORD_NO_INITIALIZE_DOMAIN      "no_initialize_domain "
#define TOMOYO_KEYWORD_NO_KEEP_DOMAIN            "no_keep_domain "
#define TOMOYO_KEYWORD_SELECT                    "select "
#define TOMOYO_KEYWORD_USE_PROFILE               "use_profile "
#define TOMOYO_KEYWORD_IGNORE_GLOBAL_ALLOW_READ  "ignore_global_allow_read"
/* A domain definition starts with <kernel>. */
#define TOMOYO_ROOT_NAME                         "<kernel>"
#define TOMOYO_ROOT_NAME_LEN                     (sizeof(TOMOYO_ROOT_NAME) - 1)

/* Index numbers for Access Controls. */
#define TOMOYO_MAC_FOR_FILE                  0  /* domain_policy.conf */
#define TOMOYO_MAX_ACCEPT_ENTRY              1
#define TOMOYO_VERBOSE                       2
#define TOMOYO_MAX_CONTROL_INDEX             3

/* Index numbers for Access Controls. */

#define TOMOYO_TYPE_SINGLE_PATH_ACL                 0
#define TOMOYO_TYPE_DOUBLE_PATH_ACL                 1

/* Index numbers for File Controls. */

/*
 * TYPE_READ_WRITE_ACL is special. TYPE_READ_WRITE_ACL is automatically set
 * if both TYPE_READ_ACL and TYPE_WRITE_ACL are set. Both TYPE_READ_ACL and
 * TYPE_WRITE_ACL are automatically set if TYPE_READ_WRITE_ACL is set.
 * TYPE_READ_WRITE_ACL is automatically cleared if either TYPE_READ_ACL or
 * TYPE_WRITE_ACL is cleared. Both TYPE_READ_ACL and TYPE_WRITE_ACL are
 * automatically cleared if TYPE_READ_WRITE_ACL is cleared.
 */

#define TOMOYO_TYPE_READ_WRITE_ACL    0
#define TOMOYO_TYPE_EXECUTE_ACL       1
#define TOMOYO_TYPE_READ_ACL          2
#define TOMOYO_TYPE_WRITE_ACL         3
#define TOMOYO_TYPE_CREATE_ACL        4
#define TOMOYO_TYPE_UNLINK_ACL        5
#define TOMOYO_TYPE_MKDIR_ACL         6
#define TOMOYO_TYPE_RMDIR_ACL         7
#define TOMOYO_TYPE_MKFIFO_ACL        8
#define TOMOYO_TYPE_MKSOCK_ACL        9
#define TOMOYO_TYPE_MKBLOCK_ACL      10
#define TOMOYO_TYPE_MKCHAR_ACL       11
#define TOMOYO_TYPE_TRUNCATE_ACL     12
#define TOMOYO_TYPE_SYMLINK_ACL      13
#define TOMOYO_TYPE_REWRITE_ACL      14
#define TOMOYO_TYPE_IOCTL_ACL        15
#define TOMOYO_TYPE_CHMOD_ACL        16
#define TOMOYO_TYPE_CHOWN_ACL        17
#define TOMOYO_TYPE_CHGRP_ACL        18
#define TOMOYO_TYPE_CHROOT_ACL       19
#define TOMOYO_TYPE_MOUNT_ACL        20
#define TOMOYO_TYPE_UMOUNT_ACL       21
#define TOMOYO_MAX_SINGLE_PATH_OPERATION 22

#define TOMOYO_TYPE_LINK_ACL         0
#define TOMOYO_TYPE_RENAME_ACL       1
#define TOMOYO_TYPE_PIVOT_ROOT_ACL   2
#define TOMOYO_MAX_DOUBLE_PATH_OPERATION 3

#define TOMOYO_DOMAINPOLICY          0
#define TOMOYO_EXCEPTIONPOLICY       1
#define TOMOYO_DOMAIN_STATUS         2
#define TOMOYO_PROCESS_STATUS        3
#define TOMOYO_MEMINFO               4
#define TOMOYO_SELFDOMAIN            5
#define TOMOYO_VERSION               6
#define TOMOYO_PROFILE               7
#define TOMOYO_MANAGER               8

/********** Structure definitions. **********/

/*
 * tomoyo_page_buffer is a structure which is used for holding a pathname
 * obtained from "struct dentry" and "struct vfsmount" pair.
 * As of now, it is 4096 bytes. If users complain that 4096 bytes is too small
 * (because TOMOYO escapes non ASCII printable characters using \ooo format),
 * we will make the buffer larger.
 */
struct tomoyo_page_buffer {
	char buffer[4096];
};

/*
 * tomoyo_path_info is a structure which is used for holding a string data
 * used by TOMOYO.
 * This structure has several fields for supporting pattern matching.
 *
 * (1) "name" is the '\0' terminated string data.
 * (2) "hash" is full_name_hash(name, strlen(name)).
 *     This allows tomoyo_pathcmp() to compare by hash before actually compare
 *     using strcmp().
 * (3) "const_len" is the length of the initial segment of "name" which
 *     consists entirely of non wildcard characters. In other words, the length
 *     which we can compare two strings using strncmp().
 * (4) "is_dir" is a bool which is true if "name" ends with "/",
 *     false otherwise.
 *     TOMOYO distinguishes directory and non-directory. A directory ends with
 *     "/" and non-directory does not end with "/".
 * (5) "is_patterned" is a bool which is true if "name" contains wildcard
 *     characters, false otherwise. This allows TOMOYO to use "hash" and
 *     strcmp() for string comparison if "is_patterned" is false.
 */
struct tomoyo_path_info {
	const char *name;
	u32 hash;          /* = full_name_hash(name, strlen(name)) */
	u16 const_len;     /* = tomoyo_const_part_length(name)     */
	bool is_dir;       /* = tomoyo_strendswith(name, "/")      */
	bool is_patterned; /* = tomoyo_path_contains_pattern(name) */
};

/*
 * tomoyo_name_entry is a structure which is used for linking
 * "struct tomoyo_path_info" into tomoyo_name_list .
 */
struct tomoyo_name_entry {
	struct list_head list;
	atomic_t users;
	struct tomoyo_path_info entry;
};

/*
 * tomoyo_path_info_with_data is a structure which is used for holding a
 * pathname obtained from "struct dentry" and "struct vfsmount" pair.
 *
 * "struct tomoyo_path_info_with_data" consists of "struct tomoyo_path_info"
 * and buffer for the pathname, while "struct tomoyo_page_buffer" consists of
 * buffer for the pathname only.
 *
 * "struct tomoyo_path_info_with_data" is intended to allow TOMOYO to release
 * both "struct tomoyo_path_info" and buffer for the pathname by single kfree()
 * so that we don't need to return two pointers to the caller. If the caller
 * puts "struct tomoyo_path_info" on stack memory, we will be able to remove
 * "struct tomoyo_path_info_with_data".
 */
struct tomoyo_path_info_with_data {
	/* Keep "head" first, for this pointer is passed to kfree(). */
	struct tomoyo_path_info head;
	char barrier1[16]; /* Safeguard for overrun. */
	char body[TOMOYO_MAX_PATHNAME_LEN];
	char barrier2[16]; /* Safeguard for overrun. */
};

/*
 * tomoyo_acl_info is a structure which is used for holding
 *
 *  (1) "list" which is linked to the ->acl_info_list of
 *      "struct tomoyo_domain_info"
 *  (2) "type" which tells type of the entry (either
 *      "struct tomoyo_single_path_acl_record" or
 *      "struct tomoyo_double_path_acl_record").
 *
 * Packing "struct tomoyo_acl_info" allows
 * "struct tomoyo_single_path_acl_record" to embed "u8" + "u16" and
 * "struct tomoyo_double_path_acl_record" to embed "u8"
 * without enlarging their structure size.
 */
struct tomoyo_acl_info {
	struct list_head list;
	u8 type;
} __packed;

/*
 * tomoyo_domain_info is a structure which is used for holding permissions
 * (e.g. "allow_read /lib/libc-2.5.so") given to each domain.
 * It has following fields.
 *
 *  (1) "list" which is linked to tomoyo_domain_list .
 *  (2) "acl_info_list" which is linked to "struct tomoyo_acl_info".
 *  (3) "domainname" which holds the name of the domain.
 *  (4) "profile" which remembers profile number assigned to this domain.
 *  (5) "is_deleted" is a bool which is true if this domain is marked as
 *      "deleted", false otherwise.
 *  (6) "quota_warned" is a bool which is used for suppressing warning message
 *      when learning mode learned too much entries.
 *  (7) "ignore_global_allow_read" is a bool which is true if this domain
 *      should ignore "allow_read" directive in exception policy.
 *  (8) "transition_failed" is a bool which is set to true when this domain was
 *      unable to create a new domain at tomoyo_find_next_domain() because the
 *      name of the domain to be created was too long or it could not allocate
 *      memory. If set to true, more than one process continued execve()
 *      without domain transition.
 *  (9) "users" is an atomic_t that holds how many "struct cred"->security
 *      are referring this "struct tomoyo_domain_info". If is_deleted == true
 *      and users == 0, this struct will be kfree()d upon next garbage
 *      collection.
 *
 * A domain's lifecycle is an analogy of files on / directory.
 * Multiple domains with the same domainname cannot be created (as with
 * creating files with the same filename fails with -EEXIST).
 * If a process reached a domain, that process can reside in that domain after
 * that domain is marked as "deleted" (as with a process can access an already
 * open()ed file after that file was unlink()ed).
 */
struct tomoyo_domain_info {
	struct list_head list;
	struct list_head acl_info_list;
	/* Name of this domain. Never NULL.          */
	const struct tomoyo_path_info *domainname;
	u8 profile;        /* Profile number to use. */
	bool is_deleted;   /* Delete flag.           */
	bool quota_warned; /* Quota warnning flag.   */
	bool ignore_global_allow_read; /* Ignore "allow_read" flag. */
	bool transition_failed; /* Domain transition failed flag. */
	atomic_t users; /* Number of referring credentials. */
};

/*
 * tomoyo_single_path_acl_record is a structure which is used for holding an
 * entry with one pathname operation (e.g. open(), mkdir()).
 * It has following fields.
 *
 *  (1) "head" which is a "struct tomoyo_acl_info".
 *  (2) "perm" which is a bitmask of permitted operations.
 *  (3) "filename" is the pathname.
 *
 * Directives held by this structure are "allow_read/write", "allow_execute",
 * "allow_read", "allow_write", "allow_create", "allow_unlink", "allow_mkdir",
 * "allow_rmdir", "allow_mkfifo", "allow_mksock", "allow_mkblock",
 * "allow_mkchar", "allow_truncate", "allow_symlink", "allow_rewrite",
 * "allow_chmod", "allow_chown", "allow_chgrp", "allow_chroot", "allow_mount"
 * and "allow_unmount".
 */
struct tomoyo_single_path_acl_record {
	struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_SINGLE_PATH_ACL */
	u8 perm_high;
	u16 perm;
	/* Pointer to single pathname. */
	const struct tomoyo_path_info *filename;
};

/*
 * tomoyo_double_path_acl_record is a structure which is used for holding an
 * entry with two pathnames operation (i.e. link(), rename() and pivot_root()).
 * It has following fields.
 *
 *  (1) "head" which is a "struct tomoyo_acl_info".
 *  (2) "perm" which is a bitmask of permitted operations.
 *  (3) "filename1" is the source/old pathname.
 *  (4) "filename2" is the destination/new pathname.
 *
 * Directives held by this structure are "allow_rename", "allow_link" and
 * "allow_pivot_root".
 */
struct tomoyo_double_path_acl_record {
	struct tomoyo_acl_info head; /* type = TOMOYO_TYPE_DOUBLE_PATH_ACL */
	u8 perm;
	/* Pointer to single pathname. */
	const struct tomoyo_path_info *filename1;
	/* Pointer to single pathname. */
	const struct tomoyo_path_info *filename2;
};

/*
 * tomoyo_io_buffer is a structure which is used for reading and modifying
 * configuration via /sys/kernel/security/tomoyo/ interface.
 * It has many fields. ->read_var1 , ->read_var2 , ->write_var1 are used as
 * cursors.
 *
 * Since the content of /sys/kernel/security/tomoyo/domain_policy is a list of
 * "struct tomoyo_domain_info" entries and each "struct tomoyo_domain_info"
 * entry has a list of "struct tomoyo_acl_info", we need two cursors when
 * reading (one is for traversing tomoyo_domain_list and the other is for
 * traversing "struct tomoyo_acl_info"->acl_info_list ).
 *
 * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 * "select ", TOMOYO seeks the cursor ->read_var1 and ->write_var1 to the
 * domain with the domainname specified by the rest of that line (NULL is set
 * if seek failed).
 * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 * "delete ", TOMOYO deletes an entry or a domain specified by the rest of that
 * line (->write_var1 is set to NULL if a domain was deleted).
 * If a line written to /sys/kernel/security/tomoyo/domain_policy starts with
 * neither "select " nor "delete ", an entry or a domain specified by that line
 * is appended.
 */
struct tomoyo_io_buffer {
	int (*read) (struct tomoyo_io_buffer *);
	int (*write) (struct tomoyo_io_buffer *);
	/* Exclusive lock for this structure.   */
	struct mutex io_sem;
	/* Index returned by tomoyo_read_lock(). */
	int reader_idx;
	/* The position currently reading from. */
	struct list_head *read_var1;
	/* Extra variables for reading.         */
	struct list_head *read_var2;
	/* The position currently writing to.   */
	struct tomoyo_domain_info *write_var1;
	/* The step for reading.                */
	int read_step;
	/* Buffer for reading.                  */
	char *read_buf;
	/* EOF flag for reading.                */
	bool read_eof;
	/* Read domain ACL of specified PID?    */
	bool read_single_domain;
	/* Extra variable for reading.          */<