security/ccsecurity/policy_io.c

/*
 * security/ccsecurity/policy_io.c
 *
 * Copyright (C) 2005-2011  NTT DATA CORPORATION
 *
 * Version: 1.8.3-rc   2011/09/29
 */

#include "internal.h"

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0)

/**
 * __wait_event_interruptible_timeout - Sleep until a condition gets true or a timeout elapses.
 *
 * @wq:        The waitqueue to wait on.
 * @condition: A C expression for the event to wait for.
 * @ret:       Timeout, in jiffies.
 *
 * Returns 0 if the @timeout elapsed, -ERESTARTSYS if it was interrupted by a
 * signal, and the remaining jiffies otherwise if the condition evaluated to
 * true before the timeout elapsed.
 *
 * This is for compatibility with older kernels.
 */
#define __wait_event_interruptible_timeout(wq, condition, ret)          \
do {                                                                    \
        wait_queue_t __wait;                                            \
        init_waitqueue_entry(&__wait, current);                         \
                                                                        \
        add_wait_queue(&wq, &__wait);                                   \
        for (;;) {                                                      \
                set_current_state(TASK_INTERRUPTIBLE);                  \
                if (condition)                                          \
                        break;                                          \
                if (!signal_pending(current)) {                         \
                        ret = schedule_timeout(ret);                    \
                        if (!ret)                                       \
                                break;                                  \
                        continue;                                       \
                }                                                       \
                ret = -ERESTARTSYS;                                     \
                break;                                                  \
        }                                                               \
        current->state = TASK_RUNNING;                                  \
        remove_wait_queue(&wq, &__wait);                                \
} while (0)

/**
 * wait_event_interruptible_timeout - Sleep until a condition gets true or a timeout elapses.
 *
 * @wq:        The waitqueue to wait on.
 * @condition: A C expression for the event to wait for.
 * @timeout:   Timeout, in jiffies.
 *
 * Returns 0 if the @timeout elapsed, -ERESTARTSYS if it was interrupted by a
 * signal, and the remaining jiffies otherwise if the condition evaluated to
 * true before the timeout elapsed.
 *
 * This is for compatibility with older kernels.
 */
#define wait_event_interruptible_timeout(wq, condition, timeout)        \
({                                                                      \
        long __ret = timeout;                                           \
        if (!(condition))                                               \
                __wait_event_interruptible_timeout(wq, condition, __ret); \
        __ret;                                                          \
})

#endif

/**
 * list_for_each_cookie - iterate over a list with cookie.
 *
 * @pos:  Pointer to "struct list_head".
 * @head: Pointer to "struct list_head".
 */
#define list_for_each_cookie(pos, head)                                 \
        for (pos = pos ? pos : srcu_dereference((head)->next, &ccs_ss); \
             pos != (head); pos = srcu_dereference(pos->next, &ccs_ss))

/* String table for operation mode. */
const char * const ccs_mode[CCS_CONFIG_MAX_MODE] = {
        [CCS_CONFIG_DISABLED]   = "disabled",
        [CCS_CONFIG_LEARNING]   = "learning",
        [CCS_CONFIG_PERMISSIVE] = "permissive",
        [CCS_CONFIG_ENFORCING]  = "enforcing"
};

/* String table for /proc/ccs/profile interface. */
const char * const ccs_mac_keywords[CCS_MAX_MAC_INDEX
                                    + CCS_MAX_MAC_CATEGORY_INDEX] = {
        /* CONFIG::file group */
        [CCS_MAC_FILE_EXECUTE]    = "execute",
        [CCS_MAC_FILE_OPEN]       = "open",
        [CCS_MAC_FILE_CREATE]     = "create",
        [CCS_MAC_FILE_UNLINK]     = "unlink",
        [CCS_MAC_FILE_GETATTR]    = "getattr",
        [CCS_MAC_FILE_MKDIR]      = "mkdir",
        [CCS_MAC_FILE_RMDIR]      = "rmdir",
        [CCS_MAC_FILE_MKFIFO]     = "mkfifo",
        [CCS_MAC_FILE_MKSOCK]     = "mksock",
        [CCS_MAC_FILE_TRUNCATE]   = "truncate",
        [CCS_MAC_FILE_SYMLINK]    = "symlink",
        [CCS_MAC_FILE_MKBLOCK]    = "mkblock",
        [CCS_MAC_FILE_MKCHAR]     = "mkchar",
        [CCS_MAC_FILE_LINK]       = "link",
        [CCS_MAC_FILE_RENAME]     = "rename",
        [CCS_MAC_FILE_CHMOD]      = "chmod",
        [CCS_MAC_FILE_CHOWN]      = "chown",
        [CCS_MAC_FILE_CHGRP]      = "chgrp",
        [CCS_MAC_FILE_IOCTL]      = "ioctl",
        [CCS_MAC_FILE_CHROOT]     = "chroot",
        [CCS_MAC_FILE_MOUNT]      = "mount",
        [CCS_MAC_FILE_UMOUNT]     = "unmount",
        [CCS_MAC_FILE_PIVOT_ROOT] = "pivot_root",
        /* CONFIG::misc group */
        [CCS_MAC_ENVIRON] = "env",
        /* CONFIG::network group */
        [CCS_MAC_NETWORK_INET_STREAM_BIND]       = "inet_stream_bind",
        [CCS_MAC_NETWORK_INET_STREAM_LISTEN]     = "inet_stream_listen",
        [CCS_MAC_NETWORK_INET_STREAM_CONNECT]    = "inet_stream_connect",
        [CCS_MAC_NETWORK_INET_STREAM_ACCEPT]     = "inet_stream_accept",
        [CCS_MAC_NETWORK_INET_DGRAM_BIND]        = "inet_dgram_bind",
        [CCS_MAC_NETWORK_INET_DGRAM_SEND]        = "inet_dgram_send",
        [CCS_MAC_NETWORK_INET_DGRAM_RECV]        = "inet_dgram_recv",
        [CCS_MAC_NETWORK_INET_RAW_BIND]          = "inet_raw_bind",
        [CCS_MAC_NETWORK_INET_RAW_SEND]          = "inet_raw_send",
        [CCS_MAC_NETWORK_INET_RAW_RECV]          = "inet_raw_recv",
        [CCS_MAC_NETWORK_UNIX_STREAM_BIND]       = "unix_stream_bind",
        [CCS_MAC_NETWORK_UNIX_STREAM_LISTEN]     = "unix_stream_listen",
        [CCS_MAC_NETWORK_UNIX_STREAM_CONNECT]    = "unix_stream_connect",
        [CCS_MAC_NETWORK_UNIX_STREAM_ACCEPT]     = "unix_stream_accept",
        [CCS_MAC_NETWORK_UNIX_DGRAM_BIND]        = "unix_dgram_bind",
        [CCS_MAC_NETWORK_UNIX_DGRAM_SEND]        = "unix_dgram_send",
        [CCS_MAC_NETWORK_UNIX_DGRAM_RECV]        = "unix_dgram_recv",
        [CCS_MAC_NETWORK_UNIX_SEQPACKET_BIND]    = "unix_seqpacket_bind",
        [CCS_MAC_NETWORK_UNIX_SEQPACKET_LISTEN]  = "unix_seqpacket_listen",
        [CCS_MAC_NETWORK_UNIX_SEQPACKET_CONNECT] = "unix_seqpacket_connect",
        [CCS_MAC_NETWORK_UNIX_SEQPACKET_ACCEPT]  = "unix_seqpacket_accept",
        /* CONFIG::ipc group */
        [CCS_MAC_SIGNAL] = "signal",
        /* CONFIG::capability group */
        [CCS_MAC_CAPABILITY_USE_ROUTE_SOCKET]  = "use_route",
        [CCS_MAC_CAPABILITY_USE_PACKET_SOCKET] = "use_packet",
        [CCS_MAC_CAPABILITY_SYS_REBOOT]        = "SYS_REBOOT",
        [CCS_MAC_CAPABILITY_SYS_VHANGUP]       = "SYS_VHANGUP",
        [CCS_MAC_CAPABILITY_SYS_SETTIME]       = "SYS_TIME",
        [CCS_MAC_CAPABILITY_SYS_NICE]          = "SYS_NICE",
        [CCS_MAC_CAPABILITY_SYS_SETHOSTNAME]   = "SYS_SETHOSTNAME",
        [CCS_MAC_CAPABILITY_USE_KERNEL_MODULE] = "use_kernel_module",
        [CCS_MAC_CAPABILITY_SYS_KEXEC_LOAD]    = "SYS_KEXEC_LOAD",
        [CCS_MAC_CAPABILITY_SYS_PTRACE]        = "SYS_PTRACE",
        /* CONFIG group */
        [CCS_MAX_MAC_INDEX + CCS_MAC_CATEGORY_FILE]       = "file",
        [CCS_MAX_MAC_INDEX + CCS_MAC_CATEGORY_NETWORK]    = "network",
        [CCS_MAX_MAC_INDEX + CCS_MAC_CATEGORY_MISC]       = "misc",
        [CCS_MAX_MAC_INDEX + CCS_MAC_CATEGORY_IPC]        = "ipc",
        [CCS_MAX_MAC_INDEX + CCS_MAC_CATEGORY_CAPABILITY] = "capability",
};

/* String table for path operation. */
const char * const ccs_path_keyword[CCS_MAX_PATH_OPERATION] = {
        [CCS_TYPE_EXECUTE]    = "execute",
        [CCS_TYPE_READ]       = "read",
        [CCS_TYPE_WRITE]      = "write",
        [CCS_TYPE_APPEND]     = "append",
        [CCS_TYPE_UNLINK]     = "unlink",
        [CCS_TYPE_GETATTR]    = "getattr",
        [CCS_TYPE_RMDIR]      = "rmdir",
        [CCS_TYPE_TRUNCATE]   = "truncate",
        [CCS_TYPE_SYMLINK]    = "symlink",
        [CCS_TYPE_CHROOT]     = "chroot",
        [CCS_TYPE_UMOUNT]     = "unmount",
};

/* String table for socket's operation. */
const char * const ccs_socket_keyword[CCS_MAX_NETWORK_OPERATION] = {
        [CCS_NETWORK_BIND]    = "bind",
        [CCS_NETWORK_LISTEN]  = "listen",
        [CCS_NETWORK_CONNECT] = "connect",
        [CCS_NETWORK_ACCEPT]  = "accept",
        [CCS_NETWORK_SEND]    = "send",
        [CCS_NETWORK_RECV]    = "recv",
};

/* String table for categories. */
static const char * const ccs_category_keywords[CCS_MAX_MAC_CATEGORY_INDEX] = {
        [CCS_MAC_CATEGORY_FILE]       = "file",
        [CCS_MAC_CATEGORY_NETWORK]    = "network",
        [CCS_MAC_CATEGORY_MISC]       = "misc",
        [CCS_MAC_CATEGORY_IPC]        = "ipc",
        [CCS_MAC_CATEGORY_CAPABILITY] = "capability",
};

/* String table for conditions. */
const char * const ccs_condition_keyword[CCS_MAX_CONDITION_KEYWORD] = {
        [CCS_TASK_UID]             = "task.uid",
        [CCS_TASK_EUID]            = "task.euid",
        [CCS_TASK_SUID]            = "task.suid",
        [CCS_TASK_FSUID]           = "task.fsuid",
        [CCS_TASK_GID]             = "task.gid",
        [CCS_TASK_EGID]            = "task.egid",
        [CCS_TASK_SGID]            = "task.sgid",
        [CCS_TASK_FSGID]           = "task.fsgid",
        [CCS_TASK_PID]             = "task.pid",
        [CCS_TASK_PPID]            = "task.ppid",
        [CCS_EXEC_ARGC]            = "exec.argc",
        [CCS_EXEC_ENVC]            = "exec.envc",
        [CCS_TYPE_IS_SOCKET]       = "socket",
        [CCS_TYPE_IS_SYMLINK]      = "symlink",
        [CCS_TYPE_IS_FILE]         = "file",
        [CCS_TYPE_IS_BLOCK_DEV]    = "block",
        [CCS_TYPE_IS_DIRECTORY]    = "directory",
        [CCS_TYPE_IS_CHAR_DEV]     = "char",
        [CCS_TYPE_IS_FIFO]         = "fifo",
        [CCS_MODE_SETUID]          = "setuid",
        [CCS_MODE_SETGID]          = "setgid",
        [CCS_MODE_STICKY]          = "sticky",
        [CCS_MODE_OWNER_READ]      = "owner_read",
        [CCS_MODE_OWNER_WRITE]     = "owner_write",
        [CCS_MODE_OWNER_EXECUTE]   = "owner_execute",
        [CCS_MODE_GROUP_READ]      = "group_read",
        [CCS_MODE_GROUP_WRITE]     = "group_write",
        [CCS_MODE_GROUP_EXECUTE]   = "group_execute",
        [CCS_MODE_OTHERS_READ]     = "others_read",
        [CCS_MODE_OTHERS_WRITE]    = "others_write",
        [CCS_MODE_OTHERS_EXECUTE]  = "others_execute",
        [CCS_TASK_TYPE]            = "task.type",
        [CCS_TASK_EXECUTE_HANDLER] = "execute_handler",
        [CCS_EXEC_REALPATH]        = "exec.realpath",
        [CCS_SYMLINK_TARGET]       = "symlink.target",
        [CCS_PATH1_UID]            = "path1.uid",
        [CCS_PATH1_GID]            = "path1.gid",
        [CCS_PATH1_INO]            = "path1.ino",
        [CCS_PATH1_MAJOR]          = "path1.major",
        [CCS_PATH1_MINOR]          = "path1.minor",
        [CCS_PATH1_PERM]           = "path1.perm",
        [CCS_PATH1_TYPE]           = "path1.type",
        [CCS_PATH1_DEV_MAJOR]      = "path1.dev_major",
        [CCS_PATH1_DEV_MINOR]      = "path1.dev_minor",
        [CCS_PATH2_UID]            = "path2.uid",
        [CCS_PATH2_GID]            = "path2.gid",
        [CCS_PATH2_INO]            = "path2.ino",
        [CCS_PATH2_MAJOR]          = "path2.major",
        [CCS_PATH2_MINOR]          = "path2.minor",
        [CCS_PATH2_PERM]           = "path2.perm",
        [CCS_PATH2_TYPE]           = "path2.type",
        [CCS_PATH2_DEV_MAJOR]      = "path2.dev_major",
        [CCS_PATH2_DEV_MINOR]      = "path2.dev_minor",
        [CCS_PATH1_PARENT_UID]     = "path1.parent.uid",
        [CCS_PATH1_PARENT_GID]     = "path1.parent.gid",
        [CCS_PATH1_PARENT_INO]     = "path1.parent.ino",
        [CCS_PATH1_PARENT_PERM]    = "path1.parent.perm",
        [CCS_PATH2_PARENT_UID]     = "path2.parent.uid",
        [CCS_PATH2_PARENT_GID]     = "path2.parent.gid",
        [CCS_PATH2_PARENT_INO]     = "path2.parent.ino",
        [CCS_PATH2_PARENT_PERM]    = "path2.parent.perm",
};

/* String table for PREFERENCE keyword. */
static const char * const ccs_pref_keywords[CCS_MAX_PREF] = {
        [CCS_PREF_MAX_AUDIT_LOG]      = "max_audit_log",
        [CCS_PREF_MAX_LEARNING_ENTRY] = "max_learning_entry",
        [CCS_PREF_ENFORCING_PENALTY]  = "enforcing_penalty",
};

/* Permit policy management by non-root user? */
static bool ccs_manage_by_non_root;

/**
 * ccs_yesno - Return "yes" or "no".
 *
 * @value: Bool value.
 *
 * Returns "yes" if @value is not 0, "no" otherwise.
 */
const char *ccs_yesno(const unsigned int value)
{
        return value ? "yes" : "no";
}

/* Prototype for ccs_addprintf(). */
static void ccs_addprintf(char *buffer, int len, const char *fmt, ...)
        __attribute__ ((format(printf, 3, 4)));

/**
 * ccs_addprintf - strncat()-like-snprintf().
 *
 * @buffer: Buffer to write to. Must be '\0'-terminated.
 * @len:    Size of @buffer.
 * @fmt:    The printf()'s format string, followed by parameters.
 *
 * Returns nothing.
 */
static void ccs_addprintf(char *buffer, int len, const char *fmt, ...)
{
        va_list args;
        const int pos = strlen(buffer);
        va_start(args, fmt);
        vsnprintf(buffer + pos, len - pos - 1, fmt, args);
        va_end(args);
}

/**
 * ccs_flush - Flush queued string to userspace's buffer.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns true if all data was flushed, false otherwise.
 */
static bool ccs_flush(struct ccs_io_buffer *head)
{
        while (head->r.w_pos) {
                const char *w = head->r.w[0];
                size_t len = strlen(w);
                if (len) {
                        if (len > head->read_user_buf_avail)
                                len = head->read_user_buf_avail;
                        if (!len)
                                return false;
                        if (copy_to_user(head->read_user_buf, w, len))
                                return false;
                        head->read_user_buf_avail -= len;
                        head->read_user_buf += len;
                        w += len;
                }
                head->r.w[0] = w;
                if (*w)
                        return false;
                /* Add '\0' for audit logs and query. */
                if (head->type == CCS_AUDIT || head->type == CCS_QUERY) {
                        if (!head->read_user_buf_avail ||
                            copy_to_user(head->read_user_buf, "", 1))
                                return false;
                        head->read_user_buf_avail--;
                        head->read_user_buf++;
                }
                head->r.w_pos--;
                for (len = 0; len < head->r.w_pos; len++)
                        head->r.w[len] = head->r.w[len + 1];
        }
        head->r.avail = 0;
        return true;
}

/**
 * ccs_set_string - Queue string to "struct ccs_io_buffer" structure.
 *
 * @head:   Pointer to "struct ccs_io_buffer".
 * @string: String to print.
 *
 * Returns nothing.
 *
 * Note that @string has to be kept valid until @head is kfree()d.
 * This means that char[] allocated on stack memory cannot be passed to
 * this function. Use ccs_io_printf() for char[] allocated on stack memory.
 */
static void ccs_set_string(struct ccs_io_buffer *head, const char *string)
{
        if (head->r.w_pos < CCS_MAX_IO_READ_QUEUE) {
                head->r.w[head->r.w_pos++] = string;
                ccs_flush(head);
        } else
                printk(KERN_WARNING "Too many words in a line.\n");
}

/* Prototype for ccs_io_printf(). */
static void ccs_io_printf(struct ccs_io_buffer *head, const char *fmt, ...)
        __attribute__ ((format(printf, 2, 3)));

/**
 * ccs_io_printf - printf() to "struct ccs_io_buffer" structure.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @fmt:  The printf()'s format string, followed by parameters.
 *
 * Returns nothing.
 */
static void ccs_io_printf(struct ccs_io_buffer *head, const char *fmt, ...)
{
        va_list args;
        size_t len;
        size_t pos = head->r.avail;
        int size = head->readbuf_size - pos;
        if (size <= 0)
                return;
        va_start(args, fmt);
        len = vsnprintf(head->read_buf + pos, size, fmt, args) + 1;
        va_end(args);
        if (pos + len >= head->readbuf_size) {
                printk(KERN_WARNING "Too many words in a line.\n");
                return;
        }
        head->r.avail += len;
        ccs_set_string(head, head->read_buf + pos);
}

/**
 * ccs_set_space - Put a space to "struct ccs_io_buffer" structure.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_set_space(struct ccs_io_buffer *head)
{
        ccs_set_string(head, " ");
}

/**
 * ccs_set_lf - Put a line feed to "struct ccs_io_buffer" structure.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static bool ccs_set_lf(struct ccs_io_buffer *head)
{
        ccs_set_string(head, "\n");
        return !head->r.w_pos;
}

/**
 * ccs_set_slash - Put a shash to "struct ccs_io_buffer" structure.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_set_slash(struct ccs_io_buffer *head)
{
        ccs_set_string(head, "/");
}

/* List of namespaces. */
LIST_HEAD(ccs_namespace_list);
/* True if namespace other than ccs_kernel_namespace is defined. */
static bool ccs_namespace_enabled;

/**
 * ccs_init_policy_namespace - Initialize namespace.
 *
 * @ns: Pointer to "struct ccs_policy_namespace".
 *
 * Returns nothing.
 */
void ccs_init_policy_namespace(struct ccs_policy_namespace *ns)
{
        unsigned int idx;
        for (idx = 0; idx < CCS_MAX_ACL_GROUPS; idx++)
                INIT_LIST_HEAD(&ns->acl_group[idx]);
        for (idx = 0; idx < CCS_MAX_GROUP; idx++)
                INIT_LIST_HEAD(&ns->group_list[idx]);
        for (idx = 0; idx < CCS_MAX_POLICY; idx++)
                INIT_LIST_HEAD(&ns->policy_list[idx]);
        ns->profile_version = 20100903;
        ccs_namespace_enabled = !list_empty(&ccs_namespace_list);
        list_add_tail_rcu(&ns->namespace_list, &ccs_namespace_list);
}

/**
 * ccs_print_namespace - Print namespace header.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_print_namespace(struct ccs_io_buffer *head)
{
        if (!ccs_namespace_enabled)
                return;
        ccs_set_string(head,
                       container_of(head->r.ns, struct ccs_policy_namespace,
                                    namespace_list)->name);
        ccs_set_space(head);
}

/**
 * ccs_assign_profile - Create a new profile.
 *
 * @ns:      Pointer to "struct ccs_policy_namespace".
 * @profile: Profile number to create.
 *
 * Returns pointer to "struct ccs_profile" on success, NULL otherwise.
 */
static struct ccs_profile *ccs_assign_profile(struct ccs_policy_namespace *ns,
                                              const unsigned int profile)
{
        struct ccs_profile *ptr;
        struct ccs_profile *entry;
        if (profile >= CCS_MAX_PROFILES)
                return NULL;
        ptr = ns->profile_ptr[profile];
        if (ptr)
                return ptr;
        entry = kzalloc(sizeof(*entry), CCS_GFP_FLAGS);
        if (mutex_lock_interruptible(&ccs_policy_lock))
                goto out;
        ptr = ns->profile_ptr[profile];
        if (!ptr && ccs_memory_ok(entry, sizeof(*entry))) {
                ptr = entry;
                ptr->default_config = CCS_CONFIG_DISABLED |
                        CCS_CONFIG_WANT_GRANT_LOG | CCS_CONFIG_WANT_REJECT_LOG;
                memset(ptr->config, CCS_CONFIG_USE_DEFAULT,
                       sizeof(ptr->config));
                ptr->pref[CCS_PREF_MAX_AUDIT_LOG] =
                        CONFIG_CCSECURITY_MAX_AUDIT_LOG;
                ptr->pref[CCS_PREF_MAX_LEARNING_ENTRY] =
                        CONFIG_CCSECURITY_MAX_ACCEPT_ENTRY;
                mb(); /* Avoid out-of-order execution. */
                ns->profile_ptr[profile] = ptr;
                entry = NULL;
        }
        mutex_unlock(&ccs_policy_lock);
out:
        kfree(entry);
        return ptr;
}

/**
 * ccs_check_profile - Check all profiles currently assigned to domains are defined.
 *
 * Returns nothing.
 */
static void ccs_check_profile(void)
{
        struct ccs_domain_info *domain;
        const int idx = ccs_read_lock();
        ccs_policy_loaded = true;
        printk(KERN_INFO "CCSecurity: 1.8.3-rc   2011/09/29\n");
        list_for_each_entry_srcu(domain, &ccs_domain_list, list, &ccs_ss) {
                const u8 profile = domain->profile;
                const struct ccs_policy_namespace *ns = domain->ns;
                if (ns->profile_version != 20100903)
                        printk(KERN_ERR
                               "Profile version %u is not supported.\n",
                               ns->profile_version);
                else if (!ns->profile_ptr[profile])
                        printk(KERN_ERR
                               "Profile %u (used by '%s') is not defined.\n",
                               profile, domain->domainname->name);
                else
                        continue;
                printk(KERN_ERR
                       "Userland tools for TOMOYO 1.8 must be installed and "
                       "policy must be initialized.\n");
                printk(KERN_ERR "Please see http://tomoyo.sourceforge.jp/1.8/ "
                       "for more information.\n");
                panic("STOP!");
        }
        ccs_read_unlock(idx);
        printk(KERN_INFO "Mandatory Access Control activated.\n");
}

/**
 * ccs_profile - Find a profile.
 *
 * @profile: Profile number to find.
 *
 * Returns pointer to "struct ccs_profile".
 */
struct ccs_profile *ccs_profile(const u8 profile)
{
        static struct ccs_profile ccs_null_profile;
        struct ccs_profile *ptr = ccs_current_namespace()->
                profile_ptr[profile];
        if (!ptr)
                ptr = &ccs_null_profile;
        return ptr;
}

/**
 * ccs_find_yesno - Find values for specified keyword.
 *
 * @string: String to check.
 * @find:   Name of keyword.
 *
 * Returns 1 if "@find=yes" was found, 0 if "@find=no" was found, -1 otherwise.
 */
static s8 ccs_find_yesno(const char *string, const char *find)
{
        const char *cp = strstr(string, find);
        if (cp) {
                cp += strlen(find);
                if (!strncmp(cp, "=yes", 4))
                        return 1;
                else if (!strncmp(cp, "=no", 3))
                        return 0;
        }
        return -1;
}

/**
 * ccs_set_uint - Set value for specified preference.
 *
 * @i:      Pointer to "unsigned int".
 * @string: String to check.
 * @find:   Name of keyword.
 *
 * Returns nothing.
 */
static void ccs_set_uint(unsigned int *i, const char *string, const char *find)
{
        const char *cp = strstr(string, find);
        if (cp)
                sscanf(cp + strlen(find), "=%u", i);
}

/**
 * ccs_set_mode - Set mode for specified profile.
 *
 * @name:    Name of functionality.
 * @value:   Mode for @name.
 * @profile: Pointer to "struct ccs_profile".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_set_mode(char *name, const char *value,
                        struct ccs_profile *profile)
{
        u8 i;
        u8 config;
        if (!strcmp(name, "CONFIG")) {
                i = CCS_MAX_MAC_INDEX + CCS_MAX_MAC_CATEGORY_INDEX;
                config = profile->default_config;
        } else if (ccs_str_starts(&name, "CONFIG::")) {
                config = 0;
                for (i = 0; i < CCS_MAX_MAC_INDEX + CCS_MAX_MAC_CATEGORY_INDEX;
                     i++) {
                        int len = 0;
                        if (i < CCS_MAX_MAC_INDEX) {
                                const u8 c = ccs_index2category[i];
                                const char *category =
                                        ccs_category_keywords[c];
                                len = strlen(category);
                                if (strncmp(name, category, len) ||
                                    name[len++] != ':' || name[len++] != ':')
                                        continue;
                        }
                        if (strcmp(name + len, ccs_mac_keywords[i]))
                                continue;
                        config = profile->config[i];
                        break;
                }
                if (i == CCS_MAX_MAC_INDEX + CCS_MAX_MAC_CATEGORY_INDEX)
                        return -EINVAL;
        } else {
                return -EINVAL;
        }
        if (strstr(value, "use_default")) {
                config = CCS_CONFIG_USE_DEFAULT;
        } else {
                u8 mode;
                for (mode = 0; mode < CCS_CONFIG_MAX_MODE; mode++)
                        if (strstr(value, ccs_mode[mode]))
                                /*
                                 * Update lower 3 bits in order to distinguish
                                 * 'config' from 'CCS_CONFIG_USE_DEAFULT'.
                                 */
                                config = (config & ~7) | mode;
                if (config != CCS_CONFIG_USE_DEFAULT) {
                        switch (ccs_find_yesno(value, "grant_log")) {
                        case 1:
                                config |= CCS_CONFIG_WANT_GRANT_LOG;
                                break;
                        case 0:
                                config &= ~CCS_CONFIG_WANT_GRANT_LOG;
                                break;
                        }
                        switch (ccs_find_yesno(value, "reject_log")) {
                        case 1:
                                config |= CCS_CONFIG_WANT_REJECT_LOG;
                                break;
                        case 0:
                                config &= ~CCS_CONFIG_WANT_REJECT_LOG;
                                break;
                        }
                }
        }
        if (i < CCS_MAX_MAC_INDEX + CCS_MAX_MAC_CATEGORY_INDEX)
                profile->config[i] = config;
        else if (config != CCS_CONFIG_USE_DEFAULT)
                profile->default_config = config;
        return 0;
}

/**
 * ccs_write_profile - Write profile table.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_write_profile(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        unsigned int i;
        char *cp;
        struct ccs_profile *profile;
        if (sscanf(data, "PROFILE_VERSION=%u", &head->w.ns->profile_version)
            == 1)
                return 0;
        i = simple_strtoul(data, &cp, 10);
        if (*cp != '-')
                return -EINVAL;
        data = cp + 1;
        profile = ccs_assign_profile(head->w.ns, i);
        if (!profile)
                return -EINVAL;
        cp = strchr(data, '=');
        if (!cp)
                return -EINVAL;
        *cp++ = '\0';
        if (!strcmp(data, "COMMENT")) {
                static DEFINE_SPINLOCK(lock);
                const struct ccs_path_info *new_comment = ccs_get_name(cp);
                const struct ccs_path_info *old_comment;
                if (!new_comment)
                        return -ENOMEM;
                spin_lock(&lock);
                old_comment = profile->comment;
                profile->comment = new_comment;
                spin_unlock(&lock);
                ccs_put_name(old_comment);
                return 0;
        }
        if (!strcmp(data, "PREFERENCE")) {
                for (i = 0; i < CCS_MAX_PREF; i++)
                        ccs_set_uint(&profile->pref[i], cp,
                                     ccs_pref_keywords[i]);
                return 0;
        }
        return ccs_set_mode(data, cp, profile);
}

/**
 * ccs_print_config - Print mode for specified functionality.
 *
 * @head:   Pointer to "struct ccs_io_buffer".
 * @config: Mode for that functionality.
 *
 * Returns nothing.
 *
 * Caller prints functionality's name.
 */
static void ccs_print_config(struct ccs_io_buffer *head, const u8 config)
{
        ccs_io_printf(head, "={ mode=%s grant_log=%s reject_log=%s }\n",
                      ccs_mode[config & 3],
                      ccs_yesno(config & CCS_CONFIG_WANT_GRANT_LOG),
                      ccs_yesno(config & CCS_CONFIG_WANT_REJECT_LOG));
}

/**
 * ccs_read_profile - Read profile table.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_read_profile(struct ccs_io_buffer *head)
{
        u8 index;
        struct ccs_policy_namespace *ns = container_of(head->r.ns, typeof(*ns),
                                                       namespace_list);
        const struct ccs_profile *profile;
        if (head->r.eof)
                return;
next:
        index = head->r.index;
        profile = ns->profile_ptr[index];
        switch (head->r.step) {
        case 0:
                ccs_print_namespace(head);
                ccs_io_printf(head, "PROFILE_VERSION=%u\n",
                              ns->profile_version);
                head->r.step++;
                break;
        case 1:
                for ( ; head->r.index < CCS_MAX_PROFILES; head->r.index++)
                        if (ns->profile_ptr[head->r.index])
                                break;
                if (head->r.index == CCS_MAX_PROFILES) {
                        head->r.eof = true;
                        return;
                }
                head->r.step++;
                break;
        case 2:
                {
                        u8 i;
                        const struct ccs_path_info *comment = profile->comment;
                        ccs_print_namespace(head);
                        ccs_io_printf(head, "%u-COMMENT=", index);
                        ccs_set_string(head, comment ? comment->name : "");
                        ccs_set_lf(head);
                        ccs_print_namespace(head);
                        ccs_io_printf(head, "%u-PREFERENCE={ ", index);
                        for (i = 0; i < CCS_MAX_PREF; i++)
                                ccs_io_printf(head, "%s=%u ",
                                              ccs_pref_keywords[i],
                                              profile->pref[i]);
                        ccs_set_string(head, "}\n");
                        head->r.step++;
                }
                break;
        case 3:
                {
                        ccs_print_namespace(head);
                        ccs_io_printf(head, "%u-%s", index, "CONFIG");
                        ccs_print_config(head, profile->default_config);
                        head->r.bit = 0;
                        head->r.step++;
                }
                break;
        case 4:
                for ( ; head->r.bit < CCS_MAX_MAC_INDEX
                              + CCS_MAX_MAC_CATEGORY_INDEX; head->r.bit++) {
                        const u8 i = head->r.bit;
                        const u8 config = profile->config[i];
                        if (config == CCS_CONFIG_USE_DEFAULT)
                                continue;
                        ccs_print_namespace(head);
                        if (i < CCS_MAX_MAC_INDEX)
                                ccs_io_printf(head, "%u-CONFIG::%s::%s", index,
                                              ccs_category_keywords
                                              [ccs_index2category[i]],
                                              ccs_mac_keywords[i]);
                        else
                                ccs_io_printf(head, "%u-CONFIG::%s", index,
                                              ccs_mac_keywords[i]);
                        ccs_print_config(head, config);
                        head->r.bit++;
                        break;
                }
                if (head->r.bit == CCS_MAX_MAC_INDEX
                    + CCS_MAX_MAC_CATEGORY_INDEX) {
                        head->r.index++;
                        head->r.step = 1;
                }
                break;
        }
        if (ccs_flush(head))
                goto next;
}

/**
 * ccs_same_manager - Check for duplicated "struct ccs_manager" entry.
 *
 * @a: Pointer to "struct ccs_acl_head".
 * @b: Pointer to "struct ccs_acl_head".
 *
 * Returns true if @a == @b, false otherwise.
 */
static bool ccs_same_manager(const struct ccs_acl_head *a,
                             const struct ccs_acl_head *b)
{
        return container_of(a, struct ccs_manager, head)->manager
                == container_of(b, struct ccs_manager, head)->manager;
}

/**
 * ccs_update_manager_entry - Add a manager entry.
 *
 * @manager:   The path to manager or the domainnamme.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_update_manager_entry(const char *manager,
                                           const bool is_delete)
{
        struct ccs_manager e = { };
        struct ccs_acl_param param = {
                /* .ns = &ccs_kernel_namespace, */
                .is_delete = is_delete,
                .list = &ccs_kernel_namespace.policy_list[CCS_ID_MANAGER],
        };
        int error = is_delete ? -ENOENT : -ENOMEM;
        if (ccs_domain_def(manager)) {
                if (!ccs_correct_domain(manager))
                        return -EINVAL;
                e.is_domain = true;
        } else {
                if (!ccs_correct_path(manager))
                        return -EINVAL;
        }
        e.manager = ccs_get_name(manager);
        if (e.manager) {
                error = ccs_update_policy(&e.head, sizeof(e), &param,
                                          ccs_same_manager);
                ccs_put_name(e.manager);
        }
        return error;
}

/**
 * ccs_write_manager - Write manager policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_write_manager(struct ccs_io_buffer *head)
{
        const char *data = head->write_buf;
        if (!strcmp(data, "manage_by_non_root")) {
                ccs_manage_by_non_root = !head->w.is_delete;
                return 0;
        }
        return ccs_update_manager_entry(data, head->w.is_delete);
}

/**
 * ccs_read_manager - Read manager policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_manager(struct ccs_io_buffer *head)
{
        if (head->r.eof)
                return;
        list_for_each_cookie(head->r.acl, &ccs_kernel_namespace.
                             policy_list[CCS_ID_MANAGER]) {
                struct ccs_manager *ptr =
                        list_entry(head->r.acl, typeof(*ptr), head.list);
                if (ptr->head.is_deleted)
                        continue;
                if (!ccs_flush(head))
                        return;
                ccs_set_string(head, ptr->manager->name);
                ccs_set_lf(head);
        }
        head->r.eof = true;
}

/**
 * ccs_manager - Check whether the current process is a policy manager.
 *
 * Returns true if the current process is permitted to modify policy
 * via /proc/ccs/ interface.
 *
 * Caller holds ccs_read_lock().
 */
static bool ccs_manager(void)
{
        struct ccs_manager *ptr;
        const char *exe;
        struct ccs_security *task = ccs_current_security();
        const struct ccs_path_info *domainname
                = ccs_current_domain()->domainname;
        bool found = false;
        if (!ccs_policy_loaded)
                return true;
        if (task->ccs_flags & CCS_TASK_IS_MANAGER)
                return true;
        if (!ccs_manage_by_non_root && (current_uid() || current_euid()))
                return false;
        exe = ccs_get_exe();
        list_for_each_entry_srcu(ptr, &ccs_kernel_namespace.
                                 policy_list[CCS_ID_MANAGER], head.list,
                                 &ccs_ss) {
                if (ptr->head.is_deleted)
                        continue;
                if (ptr->is_domain) {
                        if (ccs_pathcmp(domainname, ptr->manager))
                                continue;
                } else {
                        if (!exe || strcmp(exe, ptr->manager->name))
                                continue;
                }
                /* Set manager flag. */
                task->ccs_flags |= CCS_TASK_IS_MANAGER;
                found = true;
                break;
        }
        if (!found) { /* Reduce error messages. */
                static pid_t ccs_last_pid;
                const pid_t pid = current->pid;
                if (ccs_last_pid != pid) {
                        printk(KERN_WARNING "%s ( %s ) is not permitted to "
                               "update policies.\n", domainname->name, exe);
                        ccs_last_pid = pid;
                }
        }
        kfree(exe);
        return found;
}

/**
 * ccs_select_domain - Parse select command.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @data: String to parse.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static bool ccs_select_domain(struct ccs_io_buffer *head, const char *data)
{
        unsigned int pid;
        struct ccs_domain_info *domain = NULL;
        bool global_pid = false;
        if (strncmp(data, "select ", 7))
                return false;
        data += 7;
        if (sscanf(data, "pid=%u", &pid) == 1 ||
            (global_pid = true, sscanf(data, "global-pid=%u", &pid) == 1)) {
                struct task_struct *p;
                ccs_tasklist_lock();
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
                if (global_pid)
                        p = ccsecurity_exports.find_task_by_pid_ns(pid,
                                                               &init_pid_ns);
                else
                        p = ccsecurity_exports.find_task_by_vpid(pid);
#else
                p = find_task_by_pid(pid);
#endif
                if (p)
                        domain = ccs_task_domain(p);
                ccs_tasklist_unlock();
        } else if (!strncmp(data, "domain=", 7)) {
                if (*(data + 7) == '<')
                        domain = ccs_find_domain(data + 7);
        } else
                return false;
        head->w.domain = domain;
        /* Accessing read_buf is safe because head->io_sem is held. */
        if (!head->read_buf)
                return true; /* Do nothing if open(O_WRONLY). */
        memset(&head->r, 0, sizeof(head->r));
        head->r.print_this_domain_only = true;
        if (domain)
                head->r.domain = &domain->list;
        else
                head->r.eof = true;
        ccs_io_printf(head, "# select %s\n", data);
        if (domain && domain->is_deleted)
                ccs_set_string(head, "# This is a deleted domain.\n");
        return true;
}

/**
 * ccs_same_handler_acl - Check for duplicated "struct ccs_handler_acl" entry.
 *
 * @a: Pointer to "struct ccs_acl_info".
 * @b: Pointer to "struct ccs_acl_info".
 *
 * Returns true if @a == @b, false otherwise.
 */
static bool ccs_same_handler_acl(const struct ccs_acl_info *a,
                                 const struct ccs_acl_info *b)
{
        const struct ccs_handler_acl *p1 = container_of(a, typeof(*p1), head);
        const struct ccs_handler_acl *p2 = container_of(b, typeof(*p2), head);
        return p1->handler == p2->handler;
}

/**
 * ccs_same_task_acl - Check for duplicated "struct ccs_task_acl" entry.
 *
 * @a: Pointer to "struct ccs_acl_info".
 * @b: Pointer to "struct ccs_acl_info".
 *
 * Returns true if @a == @b, false otherwise.
 */
static bool ccs_same_task_acl(const struct ccs_acl_info *a,
                              const struct ccs_acl_info *b)
{
        const struct ccs_task_acl *p1 = container_of(a, typeof(*p1), head);
        const struct ccs_task_acl *p2 = container_of(b, typeof(*p2), head);
        return p1->domainname == p2->domainname;
}

/**
 * ccs_write_task - Update task related list.
 *
 * @param: Pointer to "struct ccs_acl_param".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static int ccs_write_task(struct ccs_acl_param *param)
{
        int error;
        const bool is_auto = ccs_str_starts(&param->data,
                                            "auto_domain_transition ");
        if (!is_auto && !ccs_str_starts(&param->data,
                                        "manual_domain_transition ")) {
                struct ccs_handler_acl e = { };
                char *handler;
                if (ccs_str_starts(&param->data, "auto_execute_handler "))
                        e.head.type = CCS_TYPE_AUTO_EXECUTE_HANDLER;
                else if (ccs_str_starts(&param->data,
                                        "denied_execute_handler "))
                        e.head.type = CCS_TYPE_DENIED_EXECUTE_HANDLER;
                else
                        return -EINVAL;
                handler = ccs_read_token(param);
                if (!ccs_correct_path(handler))
                        return -EINVAL;
                e.handler = ccs_get_name(handler);
                if (!e.handler)
                        return -ENOMEM;
                if (e.handler->is_patterned)
                        error = -EINVAL; /* No patterns allowed. */
                else
                        error = ccs_update_domain(&e.head, sizeof(e), param,
                                                  ccs_same_handler_acl, NULL);
                ccs_put_name(e.handler);
        } else {
                struct ccs_task_acl e = {
                        .head.type = is_auto ?
                        CCS_TYPE_AUTO_TASK_ACL : CCS_TYPE_MANUAL_TASK_ACL,
                        .domainname = ccs_get_domainname(param),
                };
                if (!e.domainname)
                        error = -EINVAL;
                else
                        error = ccs_update_domain(&e.head, sizeof(e), param,
                                                  ccs_same_task_acl, NULL);
                ccs_put_name(e.domainname);
        }
        return error;
}

/**
 * ccs_write_domain2 - Write domain policy.
 *
 * @ns:        Pointer to "struct ccs_policy_namespace".
 * @list:      Pointer to "struct list_head".
 * @data:      Policy to be interpreted.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static int ccs_write_domain2(struct ccs_policy_namespace *ns,
                             struct list_head *list, char *data,
                             const bool is_delete)
{
        struct ccs_acl_param param = {
                .ns = ns,
                .list = list,
                .data = data,
                .is_delete = is_delete,
        };
        static const struct {
                const char *keyword;
                int (*write) (struct ccs_acl_param *);
        } ccs_callback[7] = {
                { "file ", ccs_write_file },
                { "network inet ", ccs_write_inet_network },
                { "network unix ", ccs_write_unix_network },
                { "misc ", ccs_write_misc },
                { "capability ", ccs_write_capability },
                { "ipc signal ", ccs_write_ipc },
                { "task ", ccs_write_task },
        };
        u8 i;
        for (i = 0; i < ARRAY_SIZE(ccs_callback); i++) {
                if (!ccs_str_starts(&param.data, ccs_callback[i].keyword))
                        continue;
                return ccs_callback[i].write(&param);
        }
        return -EINVAL;
}

/**
 * ccs_delete_domain - Delete a domain.
 *
 * @domainname: The name of domain.
 *
 * Returns 0.
 */
static int ccs_delete_domain(char *domainname)
{
        struct ccs_domain_info *domain;
        struct ccs_path_info name;
        name.name = domainname;
        ccs_fill_path_info(&name);
        if (mutex_lock_interruptible(&ccs_policy_lock))
                return 0;
        /* Is there an active domain? */
        list_for_each_entry_srcu(domain, &ccs_domain_list, list, &ccs_ss) {
                /* Never delete ccs_kernel_domain. */
                if (domain == &ccs_kernel_domain)
                        continue;
                if (domain->is_deleted ||
                    ccs_pathcmp(domain->domainname, &name))
                        continue;
                domain->is_deleted = true;
                break;
        }
        mutex_unlock(&ccs_policy_lock);
        return 0;
}

/* String table for domain flags. */
const char * const ccs_dif[CCS_MAX_DOMAIN_INFO_FLAGS] = {
        [CCS_DIF_QUOTA_WARNED]      = "quota_exceeded\n",
        [CCS_DIF_TRANSITION_FAILED] = "transition_failed\n",
};

/**
 * ccs_write_domain - Write domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static int ccs_write_domain(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        struct ccs_policy_namespace *ns;
        struct ccs_domain_info *domain = head->w.domain;
        const bool is_delete = head->w.is_delete;
        const bool is_select = !is_delete && ccs_str_starts(&data, "select ");
        unsigned int profile;
        if (*data == '<') {
                domain = NULL;
                if (is_delete)
                        ccs_delete_domain(data);
                else if (is_select)
                        domain = ccs_find_domain(data);
                else
                        domain = ccs_assign_domain(data, false);
                head->w.domain = domain;
                return 0;
        }
        if (!domain)
                return -EINVAL;
        ns = domain->ns;
        if (sscanf(data, "use_profile %u\n", &profile) == 1
            && profile < CCS_MAX_PROFILES) {
                if (!ccs_policy_loaded || ns->profile_ptr[(u8) profile])
                        if (!is_delete)
                                domain->profile = (u8) profile;
                return 0;
        }
        if (sscanf(data, "use_group %u\n", &profile) == 1
            && profile < CCS_MAX_ACL_GROUPS) {
                if (!is_delete)
                        domain->group = (u8) profile;
                return 0;
        }
        for (profile = 0; profile < CCS_MAX_DOMAIN_INFO_FLAGS; profile++) {
                const char *cp = ccs_dif[profile];
                if (strncmp(data, cp, strlen(cp) - 1))
                        continue;
                domain->flags[profile] = !is_delete;
                return 0;
        }
        return ccs_write_domain2(ns, &domain->acl_info_list, data, is_delete);
}

/**
 * ccs_print_name_union - Print a ccs_name_union.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ccs_name_union".
 *
 * Returns nothing.
 */
static void ccs_print_name_union(struct ccs_io_buffer *head,
                                 const struct ccs_name_union *ptr)
{
        ccs_set_space(head);
        if (ptr->group) {
                ccs_set_string(head, "@");
                ccs_set_string(head, ptr->group->group_name->name);
        } else {
                ccs_set_string(head, ptr->filename->name);
        }
}

/**
 * ccs_print_name_union_quoted - Print a ccs_name_union with a quote.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ccs_name_union".
 *
 * Returns nothing.
 */
static void ccs_print_name_union_quoted(struct ccs_io_buffer *head,
                                        const struct ccs_name_union *ptr)
{
        if (ptr->group) {
                ccs_set_string(head, "@");
                ccs_set_string(head, ptr->group->group_name->name);
        } else {
                ccs_set_string(head, "\"");
                ccs_set_string(head, ptr->filename->name);
                ccs_set_string(head, "\"");
        }
}

/**
 * ccs_print_number_union_nospace - Print a ccs_number_union without a space.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ccs_number_union".
 *
 * Returns nothing.
 */
static void ccs_print_number_union_nospace(struct ccs_io_buffer *head,
                                           const struct ccs_number_union *ptr)
{
        if (ptr->group) {
                ccs_set_string(head, "@");
                ccs_set_string(head, ptr->group->group_name->name);
        } else {
                int i;
                unsigned long min = ptr->values[0];
                const unsigned long max = ptr->values[1];
                u8 min_type = ptr->value_type[0];
                const u8 max_type = ptr->value_type[1];
                char buffer[128];
                buffer[0] = '\0';
                for (i = 0; i < 2; i++) {
                        switch (min_type) {
                        case CCS_VALUE_TYPE_HEXADECIMAL:
                                ccs_addprintf(buffer, sizeof(buffer), "0x%lX",
                                              min);
                                break;
                        case CCS_VALUE_TYPE_OCTAL:
                                ccs_addprintf(buffer, sizeof(buffer), "0%lo",
                                              min);
                                break;
                        default:
                                ccs_addprintf(buffer, sizeof(buffer), "%lu",
                                              min);
                                break;
                        }
                        if (min == max && min_type == max_type)
                                break;
                        ccs_addprintf(buffer, sizeof(buffer), "-");
                        min_type = max_type;
                        min = max;
                }
                ccs_io_printf(head, "%s", buffer);
        }
}

/**
 * ccs_print_number_union - Print a ccs_number_union.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ccs_number_union".
 *
 * Returns nothing.
 */
static void ccs_print_number_union(struct ccs_io_buffer *head,
                                   const struct ccs_number_union *ptr)
{
        ccs_set_space(head);
        ccs_print_number_union_nospace(head, ptr);
}

/**
 * ccs_print_condition - Print condition part.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @cond: Pointer to "struct ccs_condition".
 *
 * Returns true on success, false otherwise.
 */
static bool ccs_print_condition(struct ccs_io_buffer *head,
                                const struct ccs_condition *cond)
{
        switch (head->r.cond_step) {
        case 0:
                head->r.cond_index = 0;
                head->r.cond_step++;
                if (cond->transit && cond->exec_transit) {
                        ccs_set_space(head);
                        ccs_set_string(head, cond->transit->name);
                }
                /* fall through */
        case 1:
                {
                        const u16 condc = cond->condc;
                        const struct ccs_condition_element *condp =
                                (typeof(condp)) (cond + 1);
                        const struct ccs_number_union *numbers_p =
                                (typeof(numbers_p)) (condp + condc);
                        const struct ccs_name_union *names_p =
                                (typeof(names_p))
                                (numbers_p + cond->numbers_count);
                        const struct ccs_argv *argv =
                                (typeof(argv)) (names_p + cond->names_count);
                        const struct ccs_envp *envp =
                                (typeof(envp)) (argv + cond->argc);
                        u16 skip;
                        for (skip = 0; skip < head->r.cond_index; skip++) {
                                const u8 left = condp->left;
                                const u8 right = condp->right;
                                condp++;
                                switch (left) {
                                case CCS_ARGV_ENTRY:
                                        argv++;
                                        continue;
                                case CCS_ENVP_ENTRY:
                                        envp++;
                                        continue;
                                case CCS_NUMBER_UNION:
                                        numbers_p++;
                                        break;
                                }
                                switch (right) {
                                case CCS_NAME_UNION:
                                        names_p++;
                                        break;
                                case CCS_NUMBER_UNION:
                                        numbers_p++;
                                        break;
                                }
                        }
                        while (head->r.cond_index < condc) {
                                const u8 match = condp->equals;
                                const u8 left = condp->left;
                                const u8 right = condp->right;
                                if (!ccs_flush(head))
                                        return false;
                                condp++;
                                head->r.cond_index++;
                                ccs_set_space(head);
                                switch (left) {
                                case CCS_ARGV_ENTRY:
                                        ccs_io_printf(head,
                                                      "exec.argv[%lu]%s=\"",
                                                      argv->index,
                                                      argv->is_not ? "!" : "");
                                        ccs_set_string(head,
                                                       argv->value->name);
                                        ccs_set_string(head, "\"");
                                        argv++;
                                        continue;
                                case CCS_ENVP_ENTRY:
                                        ccs_set_string(head, "exec.envp[\"");
                                        ccs_set_string(head, envp->name->name);
                                        ccs_io_printf(head, "\"]%s=",
                                                      envp->is_not ? "!" : "");
                                        if (envp->value) {
                                                ccs_set_string(head, "\"");
                                                ccs_set_string(head, envp->
                                                               value->name);
                                                ccs_set_string(head, "\"");
                                        } else {
                                                ccs_set_string(head, "NULL");
                                        }
                                        envp++;
                                        continue;
                                case CCS_NUMBER_UNION:
                                        ccs_print_number_union_nospace
                                                (head, numbers_p++);
                                        break;
                                default:
                                        ccs_set_string(head,
                                               ccs_condition_keyword[left]);
                                        break;
                                }
                                ccs_set_string(head, match ? "=" : "!=");
                                switch (right) {
                                case CCS_NAME_UNION:
                                        ccs_print_name_union_quoted
                                                (head, names_p++);
                                        break;
                                case CCS_NUMBER_UNION:
                                        ccs_print_number_union_nospace
                                                (head, numbers_p++);
                                        break;
                                default:
                                        ccs_set_string(head,
                                               ccs_condition_keyword[right]);
                                        break;
                                }
                        }
                }
                head->r.cond_step++;
                /* fall through */
        case 2:
                if (!ccs_flush(head))
                        break;
                head->r.cond_step++;
                /* fall through */
        case 3:
                if (cond->grant_log != CCS_GRANTLOG_AUTO)
                        ccs_io_printf(head, " grant_log=%s",
                                      ccs_yesno(cond->grant_log ==
                                                CCS_GRANTLOG_YES));
                if (cond->transit && !cond->exec_transit) {
                        const char *name = cond->transit->name;
                        ccs_set_string(head, " auto_domain_transition=\"");
                        ccs_set_string(head, name);
                        ccs_set_string(head, "\"");
                }
                ccs_set_lf(head);
                return true;
        }
        return false;
}

/**
 * ccs_set_group - Print "acl_group " header keyword and category name.
 *
 * @head:     Pointer to "struct ccs_io_buffer".
 * @category: Category name.
 *
 * Returns nothing.
 */
static void ccs_set_group(struct ccs_io_buffer *head, const char *category)
{
        if (head->type == CCS_EXCEPTIONPOLICY) {
                ccs_print_namespace(head);
                ccs_io_printf(head, "acl_group %u ", head->r.acl_group_index);
        }
        ccs_set_string(head, category);
}

/**
 * ccs_print_entry - Print an ACL entry.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @acl:  Pointer to an ACL entry.
 *
 * Returns true on success, false otherwise.
 */
static bool ccs_print_entry(struct ccs_io_buffer *head,
                            const struct ccs_acl_info *acl)
{
        const u8 acl_type = acl->type;
        const bool may_trigger_transition = acl->cond && acl->cond->transit;
        bool first = true;
        u8 bit;
        if (head->r.print_cond_part)
                goto print_cond_part;
        if (acl->is_deleted)
                return true;
        if (!ccs_flush(head))
                return false;
        else if (acl_type == CCS_TYPE_PATH_ACL) {
                struct ccs_path_acl *ptr
                        = container_of(acl, typeof(*ptr), head);
                const u16 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_PATH_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (head->r.print_transition_related_only &&
                            bit != CCS_TYPE_EXECUTE && !may_trigger_transition)
                                continue;
                        if (first) {
                                ccs_set_group(head, "file ");
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_path_keyword[bit]);
                }
                if (first)
                        return true;
                ccs_print_name_union(head, &ptr->name);
        } else if (acl_type == CCS_TYPE_AUTO_EXECUTE_HANDLER ||
                   acl_type == CCS_TYPE_DENIED_EXECUTE_HANDLER) {
                struct ccs_handler_acl *ptr
                        = container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "task ");
                ccs_set_string(head, acl_type == CCS_TYPE_AUTO_EXECUTE_HANDLER
                               ? "auto_execute_handler " :
                               "denied_execute_handler ");
                ccs_set_string(head, ptr->handler->name);
        } else if (acl_type == CCS_TYPE_AUTO_TASK_ACL ||
                   acl_type == CCS_TYPE_MANUAL_TASK_ACL) {
                struct ccs_task_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "task ");
                ccs_set_string(head, acl_type == CCS_TYPE_AUTO_TASK_ACL ?
                               "auto_domain_transition " :
                               "manual_domain_transition ");
                ccs_set_string(head, ptr->domainname->name);
        } else if (head->r.print_transition_related_only &&
                   !may_trigger_transition) {
                return true;
        } else if (acl_type == CCS_TYPE_MKDEV_ACL) {
                struct ccs_mkdev_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_MKDEV_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                ccs_set_group(head, "file ");
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_mac_keywords
                                       [ccs_pnnn2mac[bit]]);
                }
                if (first)
                        return true;
                ccs_print_name_union(head, &ptr->name);
                ccs_print_number_union(head, &ptr->mode);
                ccs_print_number_union(head, &ptr->major);
                ccs_print_number_union(head, &ptr->minor);
        } else if (acl_type == CCS_TYPE_PATH2_ACL) {
                struct ccs_path2_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_PATH2_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                ccs_set_group(head, "file ");
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_mac_keywords
                                       [ccs_pp2mac[bit]]);
                }
                if (first)
                        return true;
                ccs_print_name_union(head, &ptr->name1);
                ccs_print_name_union(head, &ptr->name2);
        } else if (acl_type == CCS_TYPE_PATH_NUMBER_ACL) {
                struct ccs_path_number_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_PATH_NUMBER_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                ccs_set_group(head, "file ");
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_mac_keywords
                                       [ccs_pn2mac[bit]]);
                }
                if (first)
                        return true;
                ccs_print_name_union(head, &ptr->name);
                ccs_print_number_union(head, &ptr->number);
        } else if (acl_type == CCS_TYPE_ENV_ACL) {
                struct ccs_env_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "misc env ");
                ccs_set_string(head, ptr->env->name);
        } else if (acl_type == CCS_TYPE_CAPABILITY_ACL) {
                struct ccs_capability_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "capability ");
                ccs_set_string(head, ccs_mac_keywords
                               [ccs_c2mac[ptr->operation]]);
        } else if (acl_type == CCS_TYPE_INET_ACL) {
                struct ccs_inet_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_NETWORK_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                ccs_set_group(head, "network inet ");
                                ccs_set_string(head, ccs_proto_keyword
                                               [ptr->protocol]);
                                ccs_set_space(head);
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_socket_keyword[bit]);
                }
                if (first)
                        return true;
                ccs_set_space(head);
                if (ptr->address.group) {
                        ccs_set_string(head, "@");
                        ccs_set_string(head,
                                       ptr->address.group->group_name->name);
                } else {
                        char buf[128];
                        ccs_print_ip(buf, sizeof(buf), &ptr->address);
                        ccs_io_printf(head, "%s", buf);
                }
                ccs_print_number_union(head, &ptr->port);
        } else if (acl_type == CCS_TYPE_UNIX_ACL) {
                struct ccs_unix_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                const u8 perm = ptr->perm;
                for (bit = 0; bit < CCS_MAX_NETWORK_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (first) {
                                ccs_set_group(head, "network unix ");
                                ccs_set_string(head, ccs_proto_keyword
                                               [ptr->protocol]);
                                ccs_set_space(head);
                                first = false;
                        } else {
                                ccs_set_slash(head);
                        }
                        ccs_set_string(head, ccs_socket_keyword[bit]);
                }
                if (first)
                        return true;
                ccs_print_name_union(head, &ptr->name);
        } else if (acl_type == CCS_TYPE_SIGNAL_ACL) {
                struct ccs_signal_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "ipc signal ");
                ccs_print_number_union_nospace(head, &ptr->sig);
                ccs_set_space(head);
                ccs_set_string(head, ptr->domainname->name);
        } else if (acl_type == CCS_TYPE_MOUNT_ACL) {
                struct ccs_mount_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head, "file mount");
                ccs_print_name_union(head, &ptr->dev_name);
                ccs_print_name_union(head, &ptr->dir_name);
                ccs_print_name_union(head, &ptr->fs_type);
                ccs_print_number_union(head, &ptr->flags);
        }
        if (acl->cond) {
                head->r.print_cond_part = true;
                head->r.cond_step = 0;
                if (!ccs_flush(head))
                        return false;
print_cond_part:
                if (!ccs_print_condition(head, acl->cond))
                        return false;
                head->r.print_cond_part = false;
        } else {
                ccs_set_lf(head);
        }
        return true;
}

/**
 * ccs_read_domain2 - Read domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @list: Pointer to "struct list_head".
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static bool ccs_read_domain2(struct ccs_io_buffer *head,
                             struct list_head *list)
{
        list_for_each_cookie(head->r.acl, list) {
                struct ccs_acl_info *ptr =
                        list_entry(head->r.acl, typeof(*ptr), list);
                if (!ccs_print_entry(head, ptr))
                        return false;
        }
        head->r.acl = NULL;
        return true;
}

/**
 * ccs_read_domain - Read domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_domain(struct ccs_io_buffer *head)
{
        if (head->r.eof)
                return;
        list_for_each_cookie(head->r.domain, &ccs_domain_list) {
                struct ccs_domain_info *domain =
                        list_entry(head->r.domain, typeof(*domain), list);
                switch (head->r.step) {
                        u8 i;
                case 0:
                        if (domain->is_deleted &&
                            !head->r.print_this_domain_only)
                                continue;
                        /* Print domainname and flags. */
                        ccs_set_string(head, domain->domainname->name);
                        ccs_set_lf(head);
                        ccs_io_printf(head, "use_profile %u\n",
                                      domain->profile);
                        ccs_io_printf(head, "use_group %u\n", domain->group);
                        for (i = 0; i < CCS_MAX_DOMAIN_INFO_FLAGS; i++)
                                if (domain->flags[i])
                                        ccs_set_string(head, ccs_dif[i]);
                        head->r.step++;
                        ccs_set_lf(head);
                        /* fall through */
                case 1:
                        if (!ccs_read_domain2(head, &domain->acl_info_list))
                                return;
                        head->r.step++;
                        if (!ccs_set_lf(head))
                                return;
                        /* fall through */
                case 2:
                        head->r.step = 0;
                        if (head->r.print_this_domain_only)
                                goto done;
                }
        }
done:
        head->r.eof = true;
}

/**
 * ccs_write_pid - Specify PID to obtain domainname.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
static int ccs_write_pid(struct ccs_io_buffer *head)
{
        head->r.eof = false;
        return 0;
}

/**
 * ccs_read_pid - Read information of a process.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns the domainname which the specified PID is in or
 * process information of the specified PID on success,
 * empty string otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_pid(struct ccs_io_buffer *head)
{
        char *buf = head->write_buf;
        bool task_info = false;
        bool global_pid = false;
        unsigned int pid;
        struct task_struct *p;
        struct ccs_domain_info *domain = NULL;
        u32 ccs_flags = 0;
        /* Accessing write_buf is safe because head->io_sem is held. */
        if (!buf) {
                head->r.eof = true;
                return; /* Do nothing if open(O_RDONLY). */
        }
        if (head->r.w_pos || head->r.eof)
                return;
        head->r.eof = true;
        if (ccs_str_starts(&buf, "info "))
                task_info = true;
        if (ccs_str_starts(&buf, "global-pid "))
                global_pid = true;
        pid = (unsigned int) simple_strtoul(buf, NULL, 10);
        ccs_tasklist_lock();
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 24)
        if (global_pid)
                p = ccsecurity_exports.find_task_by_pid_ns(pid, &init_pid_ns);
        else
                p = ccsecurity_exports.find_task_by_vpid(pid);
#else
        p = find_task_by_pid(pid);
#endif
        if (p) {
                domain = ccs_task_domain(p);
                ccs_flags = ccs_task_flags(p);
        }
        ccs_tasklist_unlock();
        if (!domain)
                return;
        if (!task_info) {
                ccs_io_printf(head, "%u %u ", pid, domain->profile);
                ccs_set_string(head, domain->domainname->name);
        } else {
                ccs_io_printf(head, "%u manager=%s execute_handler=%s ", pid,
                              ccs_yesno(ccs_flags &
                                        CCS_TASK_IS_MANAGER),
                              ccs_yesno(ccs_flags &
                                        CCS_TASK_IS_EXECUTE_HANDLER));
        }
}

/* String table for domain transition control keywords. */
static const char * const ccs_transition_type[CCS_MAX_TRANSITION_TYPE] = {
        [CCS_TRANSITION_CONTROL_NO_RESET]      = "no_reset_domain ",
        [CCS_TRANSITION_CONTROL_RESET]         = "reset_domain ",
        [CCS_TRANSITION_CONTROL_NO_INITIALIZE] = "no_initialize_domain ",
        [CCS_TRANSITION_CONTROL_INITIALIZE]    = "initialize_domain ",
        [CCS_TRANSITION_CONTROL_NO_KEEP]       = "no_keep_domain ",
        [CCS_TRANSITION_CONTROL_KEEP]          = "keep_domain ",
};

/* String table for grouping keywords. */
static const char * const ccs_group_name[CCS_MAX_GROUP] = {
        [CCS_PATH_GROUP]    = "path_group ",
        [CCS_NUMBER_GROUP]  = "number_group ",
        [CCS_ADDRESS_GROUP] = "address_group ",
};

/**
 * ccs_write_exception - Write exception policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_write_exception(struct ccs_io_buffer *head)
{
        const bool is_delete = head->w.is_delete;
        struct ccs_acl_param param = {
                .ns = head->w.ns,
                .is_delete = is_delete,
                .data = head->write_buf,
        };
        u8 i;
        if (ccs_str_starts(&param.data, "aggregator "))
                return ccs_write_aggregator(&param);
        if (ccs_str_starts(&param.data, "deny_autobind "))
                return ccs_write_reserved_port(&param);
        for (i = 0; i < CCS_MAX_TRANSITION_TYPE; i++)
                if (ccs_str_starts(&param.data, ccs_transition_type[i]))
                        return ccs_write_transition_control(&param, i);
        for (i = 0; i < CCS_MAX_GROUP; i++)
                if (ccs_str_starts(&param.data, ccs_group_name[i]))
                        return ccs_write_group(&param, i);
        if (ccs_str_starts(&param.data, "acl_group ")) {
                unsigned int group;
                char *data;
                group = simple_strtoul(param.data, &data, 10);
                if (group < CCS_MAX_ACL_GROUPS && *data++ == ' ')
                        return ccs_write_domain2(head->w.ns,
                                                 &head->w.ns->acl_group[group],
                                                 data, is_delete);
        }
        return -EINVAL;
}

/**
 * ccs_read_group - Read "struct ccs_path_group"/"struct ccs_number_group"/"struct ccs_address_group" list.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @idx:  Index number.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static bool ccs_read_group(struct ccs_io_buffer *head, const int idx)
{
        struct ccs_policy_namespace *ns = container_of(head->r.ns, typeof(*ns),
                                                       namespace_list);
        struct list_head *list = &ns->group_list[idx];
        list_for_each_cookie(head->r.group, list) {
                struct ccs_group *group =
                        list_entry(head->r.group, typeof(*group), head.list);
                list_for_each_cookie(head->r.acl, &group->member_list) {
                        struct ccs_acl_head *ptr =
                                list_entry(head->r.acl, typeof(*ptr), list);
                        if (ptr->is_deleted)
                                continue;
                        if (!ccs_flush(head))
                                return false;
                        ccs_print_namespace(head);
                        ccs_set_string(head, ccs_group_name[idx]);
                        ccs_set_string(head, group->group_name->name);
                        if (idx == CCS_PATH_GROUP) {
                                ccs_set_space(head);
                                ccs_set_string(head, container_of
                                               (ptr, struct ccs_path_group,
                                                head)->member_name->name);
                        } else if (idx == CCS_NUMBER_GROUP) {
                                ccs_print_number_union(head, &container_of
                                               (ptr, struct ccs_number_group,
                                                head)->number);
                        } else if (idx == CCS_ADDRESS_GROUP) {
                                char buffer[128];
                                struct ccs_address_group *member =
                                        container_of(ptr, typeof(*member),
                                                     head);
                                ccs_print_ip(buffer, sizeof(buffer),
                                             &member->address);
                                ccs_io_printf(head, " %s", buffer);
                        }
                        ccs_set_lf(head);
                }
                head->r.acl = NULL;
        }
        head->r.group = NULL;
        return true;
}

/**
 * ccs_read_policy - Read "struct ccs_..._entry" list.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @idx:  Index number.
 *
 * Returns true on success, false otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static bool ccs_read_policy(struct ccs_io_buffer *head, const int idx)
{
        struct ccs_policy_namespace *ns = container_of(head->r.ns, typeof(*ns),
                                                       namespace_list);
        struct list_head *list = &ns->policy_list[idx];
        list_for_each_cookie(head->r.acl, list) {
                struct ccs_acl_head *acl =
                        container_of(head->r.acl, typeof(*acl), list);
                if (acl->is_deleted)
                        continue;
                if (head->r.print_transition_related_only &&
                    idx != CCS_ID_TRANSITION_CONTROL)
                        continue;
                if (!ccs_flush(head))
                        return false;
                switch (idx) {
                case CCS_ID_TRANSITION_CONTROL:
                        {
                                struct ccs_transition_control *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                ccs_print_namespace(head);
                                ccs_set_string(head,
                                               ccs_transition_type[ptr->type]);
                                ccs_set_string(head, ptr->program ?
                                               ptr->program->name : "any");
                                ccs_set_string(head, " from ");
                                ccs_set_string(head, ptr->domainname ?
                                               ptr->domainname->name : "any");
                        }
                        break;
                case CCS_ID_AGGREGATOR:
                        {
                                struct ccs_aggregator *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                ccs_print_namespace(head);
                                ccs_set_string(head, "aggregator ");
                                ccs_set_string(head, ptr->original_name->name);
                                ccs_set_space(head);
                                ccs_set_string(head,
                                               ptr->aggregated_name->name);
                        }
                        break;
                case CCS_ID_RESERVEDPORT:
                        {
                                struct ccs_reserved *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                ccs_print_namespace(head);
                                ccs_set_string(head, "deny_autobind ");
                                ccs_print_number_union_nospace(head,
                                                               &ptr->port);
                        }
                        break;
                default:
                        continue;
                }
                ccs_set_lf(head);
        }
        head->r.acl = NULL;
        return true;
}

/**
 * ccs_read_exception - Read exception policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_exception(struct ccs_io_buffer *head)
{
        struct ccs_policy_namespace *ns = container_of(head->r.ns, typeof(*ns),
                                                       namespace_list);
        if (head->r.eof)
                return;
        while (head->r.step < CCS_MAX_POLICY &&
               ccs_read_policy(head, head->r.step))
                head->r.step++;
        if (head->r.step < CCS_MAX_POLICY)
                return;
        while (head->r.step < CCS_MAX_POLICY + CCS_MAX_GROUP &&
               ccs_read_group(head, head->r.step - CCS_MAX_POLICY))
                head->r.step++;
        if (head->r.step < CCS_MAX_POLICY + CCS_MAX_GROUP)
                return;
        while (head->r.step < CCS_MAX_POLICY + CCS_MAX_GROUP
               + CCS_MAX_ACL_GROUPS) {
                head->r.acl_group_index =
                        head->r.step - CCS_MAX_POLICY - CCS_MAX_GROUP;
                if (!ccs_read_domain2(head, &ns->acl_group
                                      [head->r.acl_group_index]))
                        return;
                head->r.step++;
        }
        head->r.eof = true;
}

/* Wait queue for kernel -> userspace notification. */
static DECLARE_WAIT_QUEUE_HEAD(ccs_query_wait);
/* Wait queue for userspace -> kernel notification. */
static DECLARE_WAIT_QUEUE_HEAD(ccs_answer_wait);

/* Structure for query. */
struct ccs_query {
        struct list_head list;
        char *query;
        size_t query_len;
        unsigned int serial;
        u8 timer;
        u8 answer;
        u8 retry;
};

/* The list for "struct ccs_query". */
static LIST_HEAD(ccs_query_list);

/* Lock for manipulating ccs_query_list. */
static DEFINE_SPINLOCK(ccs_query_list_lock);

/* Number of "struct file" referring /proc/ccs/query interface. */
static atomic_t ccs_query_observers = ATOMIC_INIT(0);

/**
 * ccs_truncate - Truncate a line.
 *
 * @str: String to truncate.
 *
 * Returns length of truncated @str.
 */
static int ccs_truncate(char *str)
{
        char *start = str;
        while (*(unsigned char *) str > (unsigned char) ' ')
                str++;
        *str = '\0';
        return strlen(start) + 1;
}

/**
 * ccs_add_entry - Add an ACL to current thread's domain. Used by learning mode.
 *
 * @header: Lines containing ACL.
 *
 * Returns nothing.
 */
static void ccs_add_entry(char *header)
{
        char *buffer;
        char *realpath = NULL;
        char *argv0 = NULL;
        char *symlink = NULL;
        char *handler;
        char *cp = strchr(header, '\n');
        int len;
        if (!cp)
                return;
        cp = strchr(cp + 1, '\n');
        if (!cp)
                return;
        *cp++ = '\0';
        len = strlen(cp) + 1;
        /* strstr() will return NULL if ordering is wrong. */
        if (*cp == 'f') {
                argv0 = strstr(header, " argv[]={ \"");
                if (argv0) {
                        argv0 += 10;
                        len += ccs_truncate(argv0) + 14;
                }
                realpath = strstr(header, " exec={ realpath=\"");
                if (realpath) {
                        realpath += 8;
                        len += ccs_truncate(realpath) + 6;
                }
                symlink = strstr(header, " symlink.target=\"");
                if (symlink)
                        len += ccs_truncate(symlink + 1) + 1;
        }
        handler = strstr(header, "type=execute_handler");
        if (handler)
                len += ccs_truncate(handler) + 6;
        buffer = kmalloc(len, CCS_GFP_FLAGS);
        if (!buffer)
                return;
        snprintf(buffer, len - 1, "%s", cp);
        if (handler)
                ccs_addprintf(buffer, len, " task.%s", handler);
        if (realpath)
                ccs_addprintf(buffer, len, " exec.%s", realpath);
        if (argv0)
                ccs_addprintf(buffer, len, " exec.argv[0]=%s", argv0);
        if (symlink)
                ccs_addprintf(buffer, len, "%s", symlink);
        ccs_normalize_line(buffer);
        {
                struct ccs_domain_info *domain = ccs_current_domain();
                if (!ccs_write_domain2(domain->ns, &domain->acl_info_list,
                                       buffer, false))
                        ccs_update_stat(CCS_STAT_POLICY_UPDATES);
        }
        kfree(buffer);
}

/**
 * ccs_supervisor - Ask for the supervisor's decision.
 *
 * @r:   Pointer to "struct ccs_request_info".
 * @fmt: The printf()'s format string, followed by parameters.
 *
 * Returns 0 if the supervisor decided to permit the access request which
 * violated the policy in enforcing mode, CCS_RETRY_REQUEST if the supervisor
 * decided to retry the access request which violated the policy in enforcing
 * mode, 0 if it is not in enforcing mode, -EPERM otherwise.
 */
int ccs_supervisor(struct ccs_request_info *r, const char *fmt, ...)
{
        va_list args;
        int error;
        int len;
        static unsigned int ccs_serial;
        struct ccs_query entry = { };
        bool quota_exceeded = false;
        va_start(args, fmt);
        len = vsnprintf((char *) &len, 1, fmt, args) + 1;
        va_end(args);
        /* Write /proc/ccs/audit. */
        va_start(args, fmt);
        ccs_write_log2(r, len, fmt, args);
        va_end(args);
        /* Nothing more to do if granted. */
        if (r->granted)
                return 0;
        if (r->mode)
                ccs_update_stat(r->mode);
        switch (r->mode) {
                int i;
                struct ccs_profile *p;
        case CCS_CONFIG_ENFORCING:
                error = -EPERM;
                if (atomic_read(&ccs_query_observers))
                        break;
                if (r->dont_sleep_on_enforce_error)
                        goto out;
                p = ccs_profile(r->profile);
                /* Check enforcing_penalty parameter. */
                for (i = 0; i < p->pref[CCS_PREF_ENFORCING_PENALTY]; i++) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(HZ / 10);
                }
                goto out;
        case CCS_CONFIG_LEARNING:
                error = 0;
                /* Check max_learning_entry parameter. */
                if (ccs_domain_quota_ok(r))
                        break;
                /* fall through */
        default:
                return 0;
        }
        /* Get message. */
        va_start(args, fmt);
        entry.query = ccs_init_log(r, len, fmt, args);
        va_end(args);
        if (!entry.query)
                goto out;
        entry.query_len = strlen(entry.query) + 1;
        if (!error) {
                ccs_add_entry(entry.query);
                goto out;
        }
        len = ccs_round2(entry.query_len);
        spin_lock(&ccs_query_list_lock);
        if (ccs_memory_quota[CCS_MEMORY_QUERY] &&
            ccs_memory_used[CCS_MEMORY_QUERY] + len
            >= ccs_memory_quota[CCS_MEMORY_QUERY]) {
                quota_exceeded = true;
        } else {
                entry.serial = ccs_serial++;
                entry.retry = r->retry;
                ccs_memory_used[CCS_MEMORY_QUERY] += len;
                list_add_tail(&entry.list, &ccs_query_list);
        }
        spin_unlock(&ccs_query_list_lock);
        if (quota_exceeded)
                goto out;
        /* Give 10 seconds for supervisor's opinion. */
        while (entry.timer < 10) {
                wake_up_all(&ccs_query_wait);
                if (wait_event_interruptible_timeout
                    (ccs_answer_wait, entry.answer ||
                     !atomic_read(&ccs_query_observers), HZ))
                        break;
                else
                        entry.timer++;
        }
        spin_lock(&ccs_query_list_lock);
        list_del(&entry.list);
        ccs_memory_used[CCS_MEMORY_QUERY] -= len;
        spin_unlock(&ccs_query_list_lock);
        switch (entry.answer) {
        case 3: /* Asked to retry by administrator. */
                error = CCS_RETRY_REQUEST;
                r->retry++;
                break;
        case 1:
                /* Granted by administrator. */
                error = 0;
                break;
        default:
                /* Timed out or rejected by administrator. */
                break;
        }
out:
        kfree(entry.query);
        return error;
}

/**
 * ccs_poll_query - poll() for /proc/ccs/query.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Returns POLLIN | POLLRDNORM when ready to read, 0 otherwise.
 *
 * Waits for access requests which violated policy in enforcing mode.
 */
static int ccs_poll_query(struct file *file, poll_table *wait)
{
        struct list_head *tmp;
        bool found = false;
        u8 i;
        for (i = 0; i < 2; i++) {
                spin_lock(&ccs_query_list_lock);
                list_for_each(tmp, &ccs_query_list) {
                        struct ccs_query *ptr =
                                list_entry(tmp, typeof(*ptr), list);
                        if (ptr->answer)
                                continue;
                        found = true;
                        break;
                }
                spin_unlock(&ccs_query_list_lock);
                if (found)
                        return POLLIN | POLLRDNORM;
                if (i)
                        break;
                poll_wait(file, &ccs_query_wait, wait);
        }
        return 0;
}

/**
 * ccs_read_query - Read access requests which violated policy in enforcing mode.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_read_query(struct ccs_io_buffer *head)
{
        struct list_head *tmp;
        unsigned int pos = 0;
        size_t len = 0;
        char *buf;
        if (head->r.w_pos)
                return;
        kfree(head->read_buf);
        head->read_buf = NULL;
        spin_lock(&ccs_query_list_lock);
        list_for_each(tmp, &ccs_query_list) {
                struct ccs_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->answer)
                        continue;
                if (pos++ != head->r.query_index)
                        continue;
                len = ptr->query_len;
                break;
        }
        spin_unlock(&ccs_query_list_lock);
        if (!len) {
                head->r.query_index = 0;
                return;
        }
        buf = kzalloc(len + 32, CCS_GFP_FLAGS);
        if (!buf)
                return;
        pos = 0;
        spin_lock(&ccs_query_list_lock);
        list_for_each(tmp, &ccs_query_list) {
                struct ccs_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->answer)
                        continue;
                if (pos++ != head->r.query_index)
                        continue;
                /*
                 * Some query can be skipped because ccs_query_list
                 * can change, but I don't care.
                 */
                if (len == ptr->query_len)
                        snprintf(buf, len + 31, "Q%u-%hu\n%s", ptr->serial,
                                 ptr->retry, ptr->query);
                break;
        }
        spin_unlock(&ccs_query_list_lock);
        if (buf[0]) {
                head->read_buf = buf;
                head->r.w[head->r.w_pos++] = buf;
                head->r.query_index++;
        } else {
                kfree(buf);
        }
}

/**
 * ccs_write_answer - Write the supervisor's decision.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 */
static int ccs_write_answer(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        struct list_head *tmp;
        unsigned int serial;
        unsigned int answer;
        spin_lock(&ccs_query_list_lock);
        list_for_each(tmp, &ccs_query_list) {
                struct ccs_query *ptr = list_entry(tmp, typeof(*ptr), list);
                ptr->timer = 0;
        }
        spin_unlock(&ccs_query_list_lock);
        if (sscanf(data, "A%u=%u", &serial, &answer) != 2)
                return -EINVAL;
        spin_lock(&ccs_query_list_lock);
        list_for_each(tmp, &ccs_query_list) {
                struct ccs_query *ptr = list_entry(tmp, typeof(*ptr), list);
                if (ptr->serial != serial)
                        continue;
                if (!ptr->answer)
                        ptr->answer = (u8) answer;
                break;
        }
        spin_unlock(&ccs_query_list_lock);
        wake_up_all(&ccs_answer_wait);
        return 0;
}

/**
 * ccs_read_version - Get version.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_read_version(struct ccs_io_buffer *head)
{
        if (head->r.eof)
                return;
        ccs_set_string(head, "1.8.3-pre");
        head->r.eof = true;
}

/* String table for /proc/ccs/stat interface. */
static const char * const ccs_policy_headers[CCS_MAX_POLICY_STAT] = {
        [CCS_STAT_POLICY_UPDATES]    = "update:",
        [CCS_STAT_POLICY_LEARNING]   = "violation in learning mode:",
        [CCS_STAT_POLICY_PERMISSIVE] = "violation in permissive mode:",
        [CCS_STAT_POLICY_ENFORCING]  = "violation in enforcing mode:",
};

/* String table for /proc/ccs/stat interface. */
static const char * const ccs_memory_headers[CCS_MAX_MEMORY_STAT] = {
        [CCS_MEMORY_POLICY]     = "policy:",
        [CCS_MEMORY_AUDIT]      = "audit log:",
        [CCS_MEMORY_QUERY]      = "query message:",
};

/* Timestamp counter for last updated. */
static unsigned int ccs_stat_updated[CCS_MAX_POLICY_STAT];
/* Counter for number of updates. */
static unsigned int ccs_stat_modified[CCS_MAX_POLICY_STAT];

/**
 * ccs_update_stat - Update statistic counters.
 *
 * @index: Index for policy type.
 *
 * Returns nothing.
 */
void ccs_update_stat(const u8 index)
{
        struct timeval tv;
        do_gettimeofday(&tv);
        /*
         * I don't use atomic operations because race condition is not fatal.
         */
        ccs_stat_updated[index]++;
        ccs_stat_modified[index] = tv.tv_sec;
}

/**
 * ccs_read_stat - Read statistic data.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static void ccs_read_stat(struct ccs_io_buffer *head)
{
        u8 i;
        unsigned int total = 0;
        if (head->r.eof)
                return;
        for (i = 0; i < CCS_MAX_POLICY_STAT; i++) {
                ccs_io_printf(head, "Policy %-30s %10u", ccs_policy_headers[i],
                              ccs_stat_updated[i]);
                if (ccs_stat_modified[i]) {
                        struct ccs_time stamp;
                        ccs_convert_time(ccs_stat_modified[i], &stamp);
                        ccs_io_printf(head, " (Last: %04u/%02u/%02u "
                                      "%02u:%02u:%02u)",
                                      stamp.year, stamp.month, stamp.day,
                                      stamp.hour, stamp.min, stamp.sec);
                }
                ccs_set_lf(head);
        }
        for (i = 0; i < CCS_MAX_MEMORY_STAT; i++) {
                unsigned int used = ccs_memory_used[i];
                total += used;
                ccs_io_printf(head, "Memory used by %-22s %10u",
                              ccs_memory_headers[i], used);
                used = ccs_memory_quota[i];
                if (used)
                        ccs_io_printf(head, " (Quota: %10u)", used);
                ccs_set_lf(head);
        }
        ccs_io_printf(head, "Total memory used:                    %10u\n",
                      total);
        head->r.eof = true;
}

/**
 * ccs_write_stat - Set memory quota.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
static int ccs_write_stat(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        u8 i;
        if (ccs_str_starts(&data, "Memory used by "))
                for (i = 0; i < CCS_MAX_MEMORY_STAT; i++)
                        if (ccs_str_starts(&data, ccs_memory_headers[i])) {
                                if (*data == ' ')
                                        data++;
                                ccs_memory_quota[i] =
                                        simple_strtoul(data, NULL, 10);
                        }
        return 0;
}

/**
 * ccs_open_control - open() for /proc/ccs/ interface.
 *
 * @type: Type of interface.
 * @file: Pointer to "struct file".
 *
 * Returns 0 on success, negative value otherwise.
 */
int ccs_open_control(const u8 type, struct file *file)
{
        struct ccs_io_buffer *head = kzalloc(sizeof(*head), CCS_GFP_FLAGS);
        if (!head)
                return -ENOMEM;
        mutex_init(&head->io_sem);
        head->type = type;
        if (type == CCS_EXECUTE_HANDLER) {
                /* Allow execute_handler to read process's status. */
                if (!(ccs_current_flags() & CCS_TASK_IS_EXECUTE_HANDLER)) {
                        kfree(head);
                        return -EPERM;
                }
        }
        if ((file->f_mode & FMODE_READ) && type != CCS_AUDIT &&
            type != CCS_QUERY) {
                /* Don't allocate read_buf for poll() access. */
                head->readbuf_size = 4096;
                head->read_buf = kzalloc(head->readbuf_size, CCS_GFP_FLAGS);
                if (!head->read_buf) {
                        kfree(head);
                        return -ENOMEM;
                }
        }
        if (file->f_mode & FMODE_WRITE) {
                head->writebuf_size = 4096;
                head->write_buf = kzalloc(head->writebuf_size, CCS_GFP_FLAGS);
                if (!head->write_buf) {
                        kfree(head->read_buf);
                        kfree(head);
                        return -ENOMEM;
                }
        }
        /*
         * If the file is /proc/ccs/query, increment the observer counter.
         * The obserber counter is used by ccs_supervisor() to see if
         * there is some process monitoring /proc/ccs/query.
         */
        if (type == CCS_QUERY)
                atomic_inc(&ccs_query_observers);
        file->private_data = head;
        ccs_notify_gc(head, true);
        return 0;
}

/**
 * ccs_poll_control - poll() for /proc/ccs/ interface.
 *
 * @file: Pointer to "struct file".
 * @wait: Pointer to "poll_table".
 *
 * Returns return value of poll().
 *
 * Waits for read readiness.
 * /proc/ccs/query is handled by /usr/sbin/ccs-queryd and
 * /proc/ccs/audit is handled by /usr/sbin/ccs-auditd.
 */
int ccs_poll_control(struct file *file, poll_table *wait)
{
        struct ccs_io_buffer *head = file->private_data;
        switch (head->type) {
        case CCS_AUDIT:
                return ccs_poll_log(file, wait);
        case CCS_QUERY:
                return ccs_poll_query(file, wait);
        default:
                return -ENOSYS;
        }
}

/**
 * ccs_set_namespace_cursor - Set namespace to read.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns nothing.
 */
static inline void ccs_set_namespace_cursor(struct ccs_io_buffer *head)
{
        struct list_head *ns;
        if (head->type != CCS_EXCEPTIONPOLICY && head->type != CCS_PROFILE)
                return;
        /*
         * If this is the first read, or reading previous namespace finished
         * and has more namespaces to read, update the namespace cursor.
         */
        ns = head->r.ns;
        if (!ns || (head->r.eof && ns->next != &ccs_namespace_list)) {
                /* Clearing is OK because ccs_flush() returned true. */
                memset(&head->r, 0, sizeof(head->r));
                head->r.ns = ns ? ns->next : ccs_namespace_list.next;
        }
}

/**
 * ccs_has_more_namespace - Check for unread namespaces.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns true if we have more entries to print, false otherwise.
 */
static inline bool ccs_has_more_namespace(struct ccs_io_buffer *head)
{
        return (head->type == CCS_EXCEPTIONPOLICY ||
                head->type == CCS_PROFILE) && head->r.eof &&
                head->r.ns->next != &ccs_namespace_list;
}

/**
 * ccs_read_control - read() for /proc/ccs/ interface.
 *
 * @head:       Pointer to "struct ccs_io_buffer".
 * @buffer:     Poiner to buffer to write to.
 * @buffer_len: Size of @buffer.
 *
 * Returns bytes read on success, negative value otherwise.
 */
ssize_t ccs_read_control(struct ccs_io_buffer *head, char __user *buffer,
                         const size_t buffer_len)
{
        int len;
        int idx;
        if (!access_ok(VERIFY_WRITE, buffer, buffer_len))
                return -EFAULT;
        if (mutex_lock_interruptible(&head->io_sem))
                return -EINTR;
        head->read_user_buf = buffer;
        head->read_user_buf_avail = buffer_len;
        idx = ccs_read_lock();
        if (ccs_flush(head))
                /* Call the policy handler. */
                do {
                        ccs_set_namespace_cursor(head);
                        switch (head->type) {
                        case CCS_DOMAINPOLICY:
                                ccs_read_domain(head);
                                break;
                        case CCS_EXCEPTIONPOLICY:
                                ccs_read_exception(head);
                                break;
                        case CCS_AUDIT:
                                ccs_read_log(head);
                                break;
                        case CCS_EXECUTE_HANDLER:
                        case CCS_PROCESS_STATUS:
                                ccs_read_pid(head);
                                break;
                        case CCS_VERSION:
                                ccs_read_version(head);
                                break;
                        case CCS_STAT:
                                ccs_read_stat(head);
                                break;
                        case CCS_PROFILE:
                                ccs_read_profile(head);
                                break;
                        case CCS_QUERY:
                                ccs_read_query(head);
                                break;
                        case CCS_MANAGER:
                                ccs_read_manager(head);
                                break;
                        }
                } while (ccs_flush(head) && ccs_has_more_namespace(head));
        ccs_read_unlock(idx);
        len = head->read_user_buf - buffer;
        mutex_unlock(&head->io_sem);
        return len;
}

/**
 * ccs_parse_policy - Parse a policy line.
 *
 * @head: Poiter to "struct ccs_io_buffer".
 * @line: Line to parse.
 *
 * Returns 0 on success, negative value otherwise.
 *
 * Caller holds ccs_read_lock().
 */
static int ccs_parse_policy(struct ccs_io_buffer *head, char *line)
{
        /* Delete request? */
        head->w.is_delete = !strncmp(line, "delete ", 7);
        if (head->w.is_delete)
                memmove(line, line + 7, strlen(line + 7) + 1);
        /* Selecting namespace to update. */
        if (head->type == CCS_EXCEPTIONPOLICY || head->type == CCS_PROFILE) {
                if (*line == '<') {
                        char *cp = strchr(line, ' ');
                        if (cp) {
                                *cp++ = '\0';
                                head->w.ns = ccs_assign_namespace(line);
                                memmove(line, cp, strlen(cp) + 1);
                        } else
                                head->w.ns = NULL;
                } else
                        head->w.ns = &ccs_kernel_namespace;
                /* Don't allow updating if namespace is invalid. */
                if (!head->w.ns)
                        return -ENOENT;
        }
        /* Do the update. */
        switch (head->type) {
        case CCS_DOMAINPOLICY:
                return ccs_write_domain(head);
        case CCS_EXCEPTIONPOLICY:
                return ccs_write_exception(head);
        case CCS_EXECUTE_HANDLER:
        case CCS_PROCESS_STATUS:
                return ccs_write_pid(head);
        case CCS_STAT:
                return ccs_write_stat(head);
        case CCS_PROFILE:
                return ccs_write_profile(head);
        case CCS_QUERY:
                return ccs_write_answer(head);
        case CCS_MANAGER:
                return ccs_write_manager(head);
        default:
                return -ENOSYS;
        }
}

/**
 * ccs_write_control - write() for /proc/ccs/ interface.
 *
 * @head:       Pointer to "struct ccs_io_buffer".
 * @buffer:     Pointer to buffer to read from.
 * @buffer_len: Size of @buffer.
 *
 * Returns @buffer_len on success, negative value otherwise.
 */
ssize_t ccs_write_control(struct ccs_io_buffer *head,
                          const char __user *buffer, const size_t buffer_len)
{
        int error = buffer_len;
        size_t avail_len = buffer_len;
        char *cp0 = head->write_buf;
        int idx;
        if (!access_ok(VERIFY_READ, buffer, buffer_len))
                return -EFAULT;
        if (mutex_lock_interruptible(&head->io_sem))
                return -EINTR;
        idx = ccs_read_lock();
        /* Read a line and dispatch it to the policy handler. */
        while (avail_len > 0) {
                char c;
                if (head->w.avail >= head->writebuf_size - 1) {
                        const int len = head->writebuf_size * 2;
                        char *cp = kzalloc(len, CCS_GFP_FLAGS);
                        if (!cp) {
                                error = -ENOMEM;
                                break;
                        }
                        memmove(cp, cp0, head->w.avail);
                        kfree(cp0);
                        head->write_buf = cp;
                        cp0 = cp;
                        head->writebuf_size = len;
                }
                if (get_user(c, buffer)) {
                        error = -EFAULT;
                        break;
                }
                buffer++;
                avail_len--;
                cp0[head->w.avail++] = c;
                if (c != '\n')
                        continue;
                cp0[head->w.avail - 1] = '\0';
                head->w.avail = 0;
                ccs_normalize_line(cp0);
                if (!strcmp(cp0, "reset")) {
                        head->w.ns = &ccs_kernel_namespace;
                        head->w.domain = NULL;
                        memset(&head->r, 0, sizeof(head->r));
                        continue;
                }
                /* Don't allow updating policies by non manager programs. */
                switch (head->type) {
                case CCS_PROCESS_STATUS:
                        /* This does not write anything. */
                        break;
                case CCS_DOMAINPOLICY:
                        if (ccs_select_domain(head, cp0))
                                continue;
                        /* fall through */
                case CCS_EXCEPTIONPOLICY:
                        if (!strcmp(cp0, "select transition_only")) {
                                head->r.print_transition_related_only = true;
                                continue;
                        }
                        /* fall through */
                default:
                        if (!ccs_manager()) {
                                error = -EPERM;
                                goto out;
                        }
                }
                switch (ccs_parse_policy(head, cp0)) {
                case -EPERM:
                        error = -EPERM;
                        goto out;
                case 0:
                        /* Update statistics. */
                        switch (head->type) {
                        case CCS_DOMAINPOLICY:
                        case CCS_EXCEPTIONPOLICY:
                        case CCS_STAT:
                        case CCS_PROFILE:
                        case CCS_MANAGER:
                                ccs_update_stat(CCS_STAT_POLICY_UPDATES);
                                break;
                        default:
                                break;
                        }
                        break;
                }
        }
out:
        ccs_read_unlock(idx);
        mutex_unlock(&head->io_sem);
        return error;
}

/**
 * ccs_close_control - close() for /proc/ccs/ interface.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0.
 */
int ccs_close_control(struct ccs_io_buffer *head)
{
        /*
         * If the file is /proc/ccs/query, decrement the observer counter.
         */
        if (head->type == CCS_QUERY &&
            atomic_dec_and_test(&ccs_query_observers))
                wake_up_all(&ccs_answer_wait);
        ccs_notify_gc(head, false);
        return 0;
}

/**
 * ccs_policy_io_init - Register hooks for policy I/O.
 *
 * Returns nothing.
 */
void __init ccs_policy_io_init(void)
{
        ccsecurity_ops.check_profile = ccs_check_profile;
}

/**
 * ccs_load_builtin_policy - Load built-in policy.
 *
 * Returns nothing.
 */
void __init ccs_load_builtin_policy(void)
{
        /*
         * This include file is manually created and contains built-in policy
         * named "ccs_builtin_profile", "ccs_builtin_exception_policy",
         * "ccs_builtin_domain_policy", "ccs_builtin_manager",
         * "ccs_builtin_stat" in the form of "static char [] __initdata".
         */
#include "builtin-policy.h"
        u8 i;
        const int idx = ccs_read_lock();
        for (i = 0; i < 5; i++) {
                struct ccs_io_buffer head = { };
                char *start = "";
                switch (i) {
                case 0:
                        start = ccs_builtin_profile;
                        head.type = CCS_PROFILE;
                        break;
                case 1:
                        start = ccs_builtin_exception_policy;
                        head.type = CCS_EXCEPTIONPOLICY;
                        break;
                case 2:
                        start = ccs_builtin_domain_policy;
                        head.type = CCS_DOMAINPOLICY;
                        break;
                case 3:
                        start = ccs_builtin_manager;
                        head.type = CCS_MANAGER;
                        break;
                case 4:
                        start = ccs_builtin_stat;
                        head.type = CCS_STAT;
                        break;
                }
                while (1) {
                        char *end = strchr(start, '\n');
                        if (!end)
                                break;
                        *end = '\0';
                        ccs_normalize_line(start);
                        head.write_buf = start;
                        ccs_parse_policy(&head, start);
                        start = end + 1;
                }
        }
        ccs_read_unlock(idx);
#ifdef CONFIG_CCSECURITY_OMIT_USERSPACE_LOADER
        ccs_check_profile();
#endif
}