security/ccsecurity/policy_io.c

/*
 * security/ccsecurity/policy_io.c
 *
 * Copyright (C) 2005-2010  NTT DATA CORPORATION
 *
 * Version: 1.8.0-pre   2010/08/01
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */

#include "internal.h"

static struct ccs_profile ccs_default_profile = {
#ifdef CONFIG_CCSECURITY_AUDIT
        .preference.audit_max_grant_log = CONFIG_CCSECURITY_MAX_GRANT_LOG,
        .preference.audit_max_reject_log = CONFIG_CCSECURITY_MAX_REJECT_LOG,
#endif
        .preference.audit_task_info = true,
        .preference.audit_path_info = true,
        .preference.enforcing_penalty = 0,
        .preference.learning_max_entry = CONFIG_CCSECURITY_MAX_ACCEPT_ENTRY,
        .preference.learning_exec_realpath = true,
        .preference.learning_exec_argv0 = true,
        .preference.learning_symlink_target = true,
};

/* Profile version. Currently only 20090903 is defined. */
static unsigned int ccs_profile_version;

/* Profile table. Memory is allocated as needed. */
static struct ccs_profile *ccs_profile_ptr[CCS_MAX_PROFILES];

/* String table for functionality that takes 4 modes. */
const char *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 */
static const char *ccs_mac_keywords[CCS_MAX_MAC_INDEX +
                                    CCS_MAX_CAPABILITY_INDEX +
                                    CCS_MAX_MAC_CATEGORY_INDEX] = {
        [CCS_MAC_FILE_EXECUTE]
        = "file::execute",
        [CCS_MAC_FILE_OPEN]
        = "file::open",
        [CCS_MAC_FILE_CREATE]
        = "file::create",
        [CCS_MAC_FILE_UNLINK]
        = "file::unlink",
        [CCS_MAC_FILE_MKDIR]
        = "file::mkdir",
        [CCS_MAC_FILE_RMDIR]
        = "file::rmdir",
        [CCS_MAC_FILE_MKFIFO]
        = "file::mkfifo",
        [CCS_MAC_FILE_MKSOCK]
        = "file::mksock",
        [CCS_MAC_FILE_TRUNCATE]
        = "file::truncate",
        [CCS_MAC_FILE_SYMLINK]
        = "file::symlink",
        [CCS_MAC_FILE_MKBLOCK]
        = "file::mkblock",
        [CCS_MAC_FILE_MKCHAR]
        = "file::mkchar",
        [CCS_MAC_FILE_LINK]
        = "file::link",
        [CCS_MAC_FILE_RENAME]
        = "file::rename",
        [CCS_MAC_FILE_CHMOD]
        = "file::chmod",
        [CCS_MAC_FILE_CHOWN]
        = "file::chown",
        [CCS_MAC_FILE_CHGRP]
        = "file::chgrp",
        [CCS_MAC_FILE_IOCTL]
        = "file::ioctl",
        [CCS_MAC_FILE_CHROOT]
        = "file::chroot",
        [CCS_MAC_FILE_MOUNT]
        = "file::mount",
        [CCS_MAC_FILE_UMOUNT]
        = "file::umount",
        [CCS_MAC_FILE_PIVOT_ROOT]
        = "file::pivot_root",
        [CCS_MAC_FILE_TRANSIT]
        = "file::transit",
        [CCS_MAC_ENVIRON]
        = "misc::env",
        [CCS_MAC_NETWORK_TCP_BIND]
        = "network::inet_tcp_bind",
        [CCS_MAC_NETWORK_TCP_LISTEN]
        = "network::inet_tcp_listen",
        [CCS_MAC_NETWORK_TCP_CONNECT]
        = "network::inet_tcp_connect",
        [CCS_MAC_NETWORK_TCP_ACCEPT]
        = "network::inet_tcp_accept",
        [CCS_MAC_NETWORK_UDP_BIND]
        = "network::inet_udp_bind",
        [CCS_MAC_NETWORK_UDP_SEND]
        = "network::inet_udp_send",
        [CCS_MAC_NETWORK_UDP_RECV]
        = "network::inet_udp_recv",
        [CCS_MAC_NETWORK_RAW_BIND]
        = "network::inet_raw_bind",
        [CCS_MAC_NETWORK_RAW_SEND]
        = "network::inet_raw_send",
        [CCS_MAC_NETWORK_RAW_RECV]
        = "network::inet_raw_recv",
        [CCS_MAC_SIGNAL]
        = "ipc::signal",
        [CCS_MAX_MAC_INDEX + CCS_USE_ROUTE_SOCKET]
        = "capability::use_route",
        [CCS_MAX_MAC_INDEX + CCS_USE_PACKET_SOCKET]
        = "capability::use_packet",
        [CCS_MAX_MAC_INDEX + CCS_SYS_REBOOT]
        = "capability::SYS_REBOOT",
        [CCS_MAX_MAC_INDEX + CCS_SYS_VHANGUP]
        = "capability::SYS_VHANGUP",
        [CCS_MAX_MAC_INDEX + CCS_SYS_SETTIME]
        = "capability::SYS_TIME",
        [CCS_MAX_MAC_INDEX + CCS_SYS_NICE]
        = "capability::SYS_NICE",
        [CCS_MAX_MAC_INDEX + CCS_SYS_SETHOSTNAME]
        = "capability::SYS_SETHOSTNAME",
        [CCS_MAX_MAC_INDEX + CCS_USE_KERNEL_MODULE]
        = "capability::use_kernel_module",
        [CCS_MAX_MAC_INDEX + CCS_SYS_KEXEC_LOAD]
        = "capability::SYS_KEXEC_LOAD",
        [CCS_MAX_MAC_INDEX + CCS_SYS_PTRACE]
        = "capability::SYS_PTRACE",
        [CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_INDEX
         + CCS_MAC_CATEGORY_FILE] = "file",
        [CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_INDEX
         + CCS_MAC_CATEGORY_NETWORK] = "network",
        [CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_INDEX
         + CCS_MAC_CATEGORY_MISC] = "misc",
        [CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_INDEX
         + CCS_MAC_CATEGORY_IPC] = "ipc",
        [CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_INDEX
         + CCS_MAC_CATEGORY_CAPABILITY] = "capability",
};

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

/**
 * ccs_cap2keyword - Convert capability operation to capability name.
 *
 * @operation: The capability index.
 *
 * Returns the name of the specified capability's name.
 */
const char *ccs_cap2keyword(const u8 operation)
{
        return operation < CCS_MAX_CAPABILITY_INDEX
                ? ccs_mac_keywords[CCS_MAX_MAC_INDEX + operation] + 12 : NULL;
}

/**
 * ccs_yesno - Return "yes" or "no".
 *
 * @value: Bool value.
 */
static const char *ccs_yesno(const unsigned int value)
{
        return value ? "yes" : "no";
}

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];
                int 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;
                }
                if (*w) {
                        head->r.w[0] = w;
                        return false;
                }
                /* Add '\0' for audit logs and query. */
                if (head->poll) {
                        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.
 *
 * 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");
}

/**
 * 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.
 */
void ccs_io_printf(struct ccs_io_buffer *head, const char *fmt, ...)
{
        va_list args;
        int len;
        int 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);
}

static void ccs_set_space(struct ccs_io_buffer *head)
{
        ccs_set_string(head, " ");
}

static bool ccs_set_lf(struct ccs_io_buffer *head)
{
        ccs_set_string(head, "\n");
        return !head->r.w_pos;
}

/**
 * ccs_assign_profile - Create a new profile.
 *
 * @profile: Profile number to create.
 *
 * Returns pointer to "struct ccs_profile" on success, NULL otherwise.
 */
static struct ccs_profile *ccs_assign_profile(const unsigned int profile)
{
        struct ccs_profile *ptr;
        struct ccs_profile *entry;
        if (profile >= CCS_MAX_PROFILES)
                return NULL;
        ptr = ccs_profile_ptr[profile];
        if (ptr)
                return ptr;
        entry = kzalloc(sizeof(*entry), CCS_GFP_FLAGS);
        if (mutex_lock_interruptible(&ccs_policy_lock))
                goto out;
        ptr = ccs_profile_ptr[profile];
        if (!ptr && ccs_memory_ok(entry, sizeof(*entry))) {
                ptr = entry;
                ptr->default_config = CCS_CONFIG_DISABLED |
                        CCS_CONFIG_VERBOSE |
                        CCS_CONFIG_WANT_GRANT_LOG | CCS_CONFIG_WANT_REJECT_LOG;
                memset(ptr->config, CCS_CONFIG_USE_DEFAULT,
                       sizeof(ptr->config));
                mb(); /* Avoid out-of-order execution. */
                ccs_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.
 */
static void ccs_check_profile(void)
{
        struct ccs_domain_info *domain;
        const int idx = ccs_read_lock();
        ccs_policy_loaded = true;
        list_for_each_entry_rcu(domain, &ccs_domain_list, list) {
                const u8 profile = domain->profile;
                if (ccs_profile_ptr[profile])
                        continue;
                panic("Profile %u (used by '%s') not defined.\n",
                      profile, domain->domainname->name);
        }
        ccs_read_unlock(idx);
        if (ccs_profile_version != 20090903)
                panic("Profile version %u is not supported.\n",
                      ccs_profile_version);
        printk(KERN_INFO "CCSecurity: 1.8.0-pre   2010/08/01\n");
        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)
{
        struct ccs_profile *ptr = ccs_profile_ptr[profile];
        if (!ccs_policy_loaded)
                return &ccs_default_profile;
        BUG_ON(!ptr);
        return ptr;
}

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;
}

static void ccs_set_bool(bool *b, const char *string, const char *find)
{
        switch (ccs_find_yesno(string, find)) {
        case 1:
                *b = true;
                break;
        case 0:
                *b = false;
                break;
        }
}

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);
}

static void ccs_set_pref(const char *name, const char *value,
                         struct ccs_profile *profile)
{
        if (!strcmp(name, "audit")) {
#ifdef CONFIG_CCSECURITY_AUDIT
                ccs_set_uint(&profile->preference.audit_max_grant_log, value,
                             "max_grant_log");
                ccs_set_uint(&profile->preference.audit_max_reject_log, value,
                             "max_reject_log");
#endif
                ccs_set_bool(&profile->preference.audit_task_info, value,
                             "task_info");
                ccs_set_bool(&profile->preference.audit_path_info, value,
                             "path_info");
                return;
        }
        if (!strcmp(name, "enforcing")) {
                ccs_set_uint(&profile->preference.enforcing_penalty, value,
                             "penalty");
                return;
        }
        if (!strcmp(name, "learning")) {
                ccs_set_uint(&profile->preference.learning_max_entry, value,
                             "max_entry");
                ccs_set_bool(&profile->preference.learning_exec_realpath,
                             value, "exec.realpath");
                ccs_set_bool(&profile->preference.learning_exec_argv0, value,
                             "exec.argv0");
                ccs_set_bool(&profile->preference.learning_symlink_target,
                             value, "symlink.target");
                return;
        }
}

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_CAPABILITY_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_CAPABILITY_INDEX
                             + CCS_MAX_MAC_CATEGORY_INDEX; i++) {
                        if (strcmp(name, ccs_mac_keywords[i]))
                                continue;
                        config = profile->config[i];
                        break;
                }
                if (i == CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_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, "verbose")) {
                        case 1:
                                config |= CCS_CONFIG_VERBOSE;
                                break;
                        case 0:
                                config &= ~CCS_CONFIG_VERBOSE;
                                break;
                        }
#ifdef CONFIG_CCSECURITY_AUDIT
                        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;
                        }
#endif
                }
        }
        if (i < CCS_MAX_MAC_INDEX + CCS_MAX_CAPABILITY_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", &ccs_profile_version) == 1)
                return 0;
        i = simple_strtoul(data, &cp, 10);
        if (*cp != '-')
                return -EINVAL;
        data = cp + 1;
        profile = ccs_assign_profile(i);
        if (!profile)
                return -EINVAL;
        cp = strchr(data, '=');
        if (!cp)
                return -EINVAL;
        *cp++ = '\0';
        if (ccs_str_starts(&data, "PREFERENCE::")) {
                ccs_set_pref(data, cp, profile);
                return 0;
        }
        if (!strcmp(data, "COMMENT")) {
                const struct ccs_path_info *old_comment = profile->comment;
                profile->comment = ccs_get_name(cp);
                ccs_put_name(old_comment);
                return 0;
        }
        return ccs_set_mode(data, cp, profile);
}

static void ccs_print_preference(struct ccs_io_buffer *head, const int index)
{
        struct ccs_profile *profile = ccs_profile_ptr[index];
        struct ccs_preference *pref = &profile->preference;
        ccs_io_printf(head, "%u-PREFERENCE::%s={ "
#ifdef CONFIG_CCSECURITY_AUDIT
                      "max_grant_log=%u max_reject_log=%u "
#endif
                      "task_info=%s path_info=%s }\n", index,
                      "audit",
#ifdef CONFIG_CCSECURITY_AUDIT
                      pref->audit_max_grant_log,
                      pref->audit_max_reject_log,
#endif
                      ccs_yesno(pref->audit_task_info),
                      ccs_yesno(pref->audit_path_info));
        ccs_io_printf(head, "%u-PREFERENCE::%s={ "
                      "max_entry=%u exec.realpath=%s "
                      "exec.argv0=%s symlink.target=%s }\n",
                      index, "learning",
                      pref->learning_max_entry,
                      ccs_yesno(pref->learning_exec_realpath),
                      ccs_yesno(pref->learning_exec_argv0),
                      ccs_yesno(pref->learning_symlink_target));
        ccs_io_printf(head, "%u-PREFERENCE::%s={ penalty=%u }\n", index,
                      "enforcing", pref->enforcing_penalty);
}

static void ccs_print_config(struct ccs_io_buffer *head, const u8 config)
{
        ccs_io_printf(head, "={ mode=%s verbose=%s", ccs_mode[config & 3],
                      ccs_yesno(config & CCS_CONFIG_VERBOSE));
#ifdef CONFIG_CCSECURITY_AUDIT
        ccs_io_printf(head, " grant_log=%s reject_log=%s",
                      ccs_yesno(config & CCS_CONFIG_WANT_GRANT_LOG),
                      ccs_yesno(config & CCS_CONFIG_WANT_REJECT_LOG));
#endif
        ccs_set_string(head, " }\n");
}

/**
 * ccs_read_profile - Read profile table.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 */
static void ccs_read_profile(struct ccs_io_buffer *head)
{
        u8 index;
        const struct ccs_profile *profile;
 next:
        index = head->r.index;
        profile = ccs_profile_ptr[index];
        switch (head->r.step) {
        case 0:
                ccs_io_printf(head, "PROFILE_VERSION=%s\n", "20090903");
                head->r.step++;
                break;
        case 1:
                for ( ; head->r.index < CCS_MAX_PROFILES;
                      head->r.index++)
                        if (ccs_profile_ptr[head->r.index])
                                break;
                if (head->r.index == CCS_MAX_PROFILES)
                        return;
                head->r.step++;
                break;
        case 2:
                {
                        const struct ccs_path_info *comment = profile->comment;
                        ccs_io_printf(head, "%u-COMMENT=", index);
                        ccs_set_string(head, comment ? comment->name : "");
                        ccs_set_lf(head);
                        head->r.step++;
                }
                break;
        case 3:
                {
                        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_CAPABILITY_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_io_printf(head, "%u-%s%s", index, "CONFIG::",
                                      ccs_mac_keywords[i]);
                        ccs_print_config(head, config);
                        head->r.bit++;
                        break;
                }
                if (head->r.bit == CCS_MAX_MAC_INDEX
                    + CCS_MAX_CAPABILITY_INDEX
                    + CCS_MAX_MAC_CATEGORY_INDEX) {
                        ccs_print_preference(head, index);
                        head->r.index++;
                        head->r.step = 1;
                }
                break;
        }
        if (ccs_flush(head))
                goto next;
}

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 int ccs_update_manager_entry(const char *manager, const bool is_delete)
{
        struct ccs_manager e = { };
        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)
                return error;
        error = ccs_update_policy(&e.head, sizeof(e), is_delete,
                                  &ccs_policy_list[CCS_ID_MANAGER],
                                  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)
{
        char *data = head->write_buf;
        bool is_delete = ccs_str_starts(&data, CCS_KEYWORD_DELETE);
        if (!strcmp(data, "manage_by_non_root")) {
                ccs_manage_by_non_root = !is_delete;
                return 0;
        }
        return ccs_update_manager_entry(data, is_delete);
}

/**
 * ccs_read_manager - Read manager policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * 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_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 task_struct *task = current;
        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_rcu(ptr, &ccs_policy_list[CCS_ID_MANAGER],
                                head.list) {
                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_find_condition_part - Find condition part from the statement.
 *
 * @data: String to parse.
 *
 * Returns pointer to the condition part if it was found in the statement,
 * NULL otherwise.
 */
static char *ccs_find_condition_part(char *data)
{
        char *cp = strstr(data, " if ");
        if (!cp)
                cp = strstr(data, " ; set ");
        if (cp)
                *cp++ = '\0';
        return cp;
}

/**
 * ccs_select_one - 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_one(struct ccs_io_buffer *head, const char *data)
{
        unsigned int pid;
        struct ccs_domain_info *domain = NULL;
        bool global_pid = false;
        if (!strcmp(data, "execute")) {
                head->r.print_execute_only = true;
                return true;
        }
        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 (ccs_domain_def(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;
}

static int ccs_write_domain2(char *data, struct ccs_domain_info *domain,
                             const bool is_delete)
{
        static const struct {
                const char *keyword;
                int (*write) (char *, struct ccs_domain_info *,
                              struct ccs_condition *, const bool);
        } ccs_callback[4] = {
                { "network ", ccs_write_network },
                { "misc ", ccs_write_misc },
                { "capability ", ccs_write_capability },
                { "ipc ", ccs_write_ipc },
        };
        int (*write) (char *, struct ccs_domain_info *, struct ccs_condition *,
                      const bool) = ccs_write_file;
        int error;
        u8 i;
        struct ccs_condition *cond = NULL;
        char *cp = ccs_find_condition_part(data);
        if (cp) {
                cond = ccs_get_condition(cp);
                if (!cond)
                        return -EINVAL;
        }
        for (i = 0; i < 4; i++) {
                if (!ccs_str_starts(&data, ccs_callback[i].keyword))
                        continue;
                write = ccs_callback[i].write;
                break;
        }
        error = write(data, domain, cond, is_delete);
        if (cond)
                ccs_put_condition(cond);
        return error;
}

static const char *ccs_dif[CCS_MAX_DOMAIN_INFO_FLAGS] = {
        [CCS_DIF_QUOTA_WARNED] = CCS_KEYWORD_QUOTA_EXCEEDED "\n",
        [CCS_DIF_TRANSITION_FAILED] = CCS_KEYWORD_TRANSITION_FAILED "\n"
};
        
/**
 * ccs_write_domain - Write domain policy.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_write_domain(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        struct ccs_domain_info *domain = head->w.domain;
        bool is_delete = false;
        bool is_select = false;
        unsigned int profile;
        if (ccs_str_starts(&data, CCS_KEYWORD_DELETE))
                is_delete = true;
        else if (ccs_str_starts(&data, CCS_KEYWORD_SELECT))
                is_select = true;
        if (is_select && ccs_select_one(head, data))
                return 0;
        /* Don't allow updating policies by non manager programs. */
        if (!ccs_manager())
                return -EPERM;
        if (ccs_domain_def(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, 0, 0, false);
                head->w.domain = domain;
                return 0;
        }
        if (!domain)
                return -EINVAL;

        if (sscanf(data, CCS_KEYWORD_USE_PROFILE "%u", &profile) == 1
            && profile < CCS_MAX_PROFILES) {
                if (!ccs_policy_loaded || ccs_profile_ptr[(u8) profile])
                        domain->profile = (u8) profile;
                return 0;
        }
        if (sscanf(data, CCS_KEYWORD_USE_GROUP "%u", &profile) == 1
            && profile < CCS_MAX_ACL_GROUPS) {
                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(data, domain, 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".
 */
static void ccs_print_name_union(struct ccs_io_buffer *head,
                                 const struct ccs_name_union *ptr)
{
        const bool cond = head->r.print_cond_part;
        if (!cond)
                ccs_set_space(head);
        if (ptr->is_group) {
                ccs_set_string(head, "@");
                ccs_set_string(head, ptr->group->group_name->name);
        } else {
                if (cond)
                        ccs_set_string(head, "\"");
                ccs_set_string(head, ptr->filename->name);
                if (cond)
                        ccs_set_string(head, "\"");
        }
}

/**
 * ccs_print_number_union - Print a ccs_number_union.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 * @ptr:  Pointer to "struct ccs_number_union".
 */
static void ccs_print_number_union(struct ccs_io_buffer *head,
                                   const struct ccs_number_union *ptr)
{
        if (!head->r.print_cond_part)
                ccs_set_space(head);
        if (ptr->is_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_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:
                { 
                        if (cond->condc)
                                ccs_set_string(head, " if");
                        head->r.cond_index = 0;
                        head->r.cond_step++;
                }
                /* 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[%u]%s\"%s\"",
                                                      argv->index,
                                                      argv->is_not ?
                                                      "!=" : "=",
                                                      argv->value->name);
                                        argv++;
                                        continue;
                                case CCS_ENVP_ENTRY:
                                        ccs_io_printf(head,
                                                      "exec.envp[\"%s\"]%s",
                                                      envp->name->name,
                                                      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(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(head, names_p++);
                                        break;
                                case CCS_NUMBER_UNION:
                                        ccs_print_number_union(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:
                {
                        u8 j;
                        const u8 i = cond->post_state[3];
                        if (i)
                                ccs_set_string(head, " ; set");
                        for (j = 0; j < 3; j++)
                                if ((i & (1 << j)))
                                        ccs_io_printf(head, 
                                                      " task.state[%u]=%u", j,
                                                      cond->post_state[j]);
                        if (i & (1 << 4))
                                ccs_io_printf(head, " audit=%s",
                                              ccs_yesno(cond->post_state[4]));
                }
                ccs_set_lf(head);
                return true;
        }
        return false;
}

/**
 * ccs_fns - Find next set bit.
 *
 * @perm: 8 bits value.
 * @bit:  First bit to find.
 *
 * Returns next set bit on success, 8 otherwise.
 */
static u8 ccs_fns(const u8 perm, u8 bit)
{
        for ( ; bit < 8; bit++)
                if (perm & (1 << bit))
                        break;
        return bit;
}

static void ccs_set_group(struct ccs_io_buffer *head)
{
        if (head->type == CCS_EXCEPTIONPOLICY)
                ccs_io_printf(head, "acl_group %u ", head->r.group_index);
}

/**
 * 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;
        u8 bit;
        if (head->r.print_cond_part)
                goto print_cond_part;
        if (acl->is_deleted)
                return true;
 next:
        bit = head->r.bit;
        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 < CCS_MAX_PATH_OPERATION; bit++) {
                        if (!(perm & (1 << bit)))
                                continue;
                        if (head->r.print_execute_only &&
                            bit != CCS_TYPE_EXECUTE && bit != CCS_TYPE_TRANSIT)
                                continue;
                        break;
                }
                if (bit >= CCS_MAX_PATH_OPERATION)
                        goto done;
                ccs_set_group(head);
                ccs_set_string(head, "file ");
                ccs_set_string(head, ccs_path_keyword[bit]);
                ccs_print_name_union(head, &ptr->name);
        } else if (acl_type == CCS_TYPE_EXECUTE_HANDLER ||
                   acl_type == CCS_TYPE_DENIED_EXECUTE_HANDLER) {
                struct ccs_execute_handler *ptr
                        = container_of(acl, typeof(*ptr), head);
                ccs_set_group(head);
                ccs_io_printf(head, "%s ",
                              acl_type == CCS_TYPE_EXECUTE_HANDLER ?
                              CCS_KEYWORD_EXECUTE_HANDLER :
                              CCS_KEYWORD_DENIED_EXECUTE_HANDLER);
                ccs_set_string(head, ptr->handler->name);
        } else if (head->r.print_execute_only) {
                return true;
        } else if (acl_type == CCS_TYPE_MKDEV_ACL) {
                struct ccs_mkdev_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                bit = ccs_fns(ptr->perm, bit);
                if (bit >= CCS_MAX_MKDEV_OPERATION)
                        goto done;
                ccs_set_group(head);
                ccs_set_string(head, "file ");
                ccs_set_string(head, ccs_mkdev_keyword[bit]);
                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);
                bit = ccs_fns(ptr->perm, bit);
                if (bit >= CCS_MAX_PATH2_OPERATION)
                        goto done;
                ccs_set_group(head);
                ccs_set_string(head, "file ");
                ccs_set_string(head, ccs_path2_keyword[bit]);
                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);
                bit = ccs_fns(ptr->perm, bit);
                if (bit >= CCS_MAX_PATH_NUMBER_OPERATION)
                        goto done;
                ccs_set_group(head);
                ccs_set_string(head, "file ");
                ccs_set_string(head, ccs_path_number_keyword[bit]);
                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);
                ccs_set_string(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);
                ccs_set_string(head, "capability ");
                ccs_set_string(head, ccs_cap2keyword(ptr->operation));
        } else if (acl_type == CCS_TYPE_IP_NETWORK_ACL) {
                struct ccs_ip_network_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                bit = ccs_fns(ptr->perm, bit);
                if (bit >= CCS_MAX_NETWORK_OPERATION)
                        goto done;
                ccs_set_group(head);
                ccs_set_string(head, "network ");
                ccs_set_string(head, ccs_net_protocol_keyword[ptr->protocol]);
                ccs_set_space(head);
                ccs_set_string(head, ccs_net_keyword[bit]);
                ccs_set_space(head);
                switch (ptr->address_type) {
                        char buf[128];
                case CCS_IP_ADDRESS_TYPE_ADDRESS_GROUP:
                        ccs_set_string(head, "@");
                        ccs_set_string(head,
                                       ptr->address.group->group_name->name);
                        break;
                case CCS_IP_ADDRESS_TYPE_IPv4:
                        ccs_print_ipv4(buf, sizeof(buf), ptr->address.ipv4.min,
                                       ptr->address.ipv4.max);
                        ccs_io_printf(head, "%s", buf);
                        break;
                case CCS_IP_ADDRESS_TYPE_IPv6:
                        ccs_print_ipv6(buf, sizeof(buf), ptr->address.ipv6.min,
                                       ptr->address.ipv6.max);
                        ccs_io_printf(head, "%s", buf);
                        break;
                }
                ccs_print_number_union(head, &ptr->port);
        } else if (acl_type == CCS_TYPE_SIGNAL_ACL) {
                struct ccs_signal_acl *ptr =
                        container_of(acl, typeof(*ptr), head);
                ccs_set_group(head);
                ccs_set_string(head, "ipc signal ");
                ccs_io_printf(head, "%u ", ptr->sig);
                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);
                ccs_io_printf(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);
        }
        head->r.bit = bit + 1;
        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);
        }
        switch (acl_type) {
        case CCS_TYPE_PATH_ACL:
        case CCS_TYPE_MKDEV_ACL:
        case CCS_TYPE_PATH2_ACL:
        case CCS_TYPE_PATH_NUMBER_ACL:
        case CCS_TYPE_IP_NETWORK_ACL:
                goto next;
        }
 done:
        head->r.bit = 0;
        return true;
}

/**
 * ccs_read_domain2 - Read domain policy.
 *
 * @head:   Pointer to "struct ccs_io_buffer".
 * @domain: Pointer to "struct ccs_domain_info".
 *
 * Caller holds ccs_read_lock().
 *
 * Returns true on success, false otherwise.
 */
static bool ccs_read_domain2(struct ccs_io_buffer *head,
                             struct ccs_domain_info *domain)
{
        list_for_each_cookie(head->r.acl, &domain->acl_info_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".
 *
 * 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, CCS_KEYWORD_USE_PROFILE "%u\n",
                                      domain->profile);
                        ccs_io_printf(head, CCS_KEYWORD_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))
                                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_domain_profile - Assign profile for specified domain.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns 0 on success, -EINVAL otherwise.
 *
 * This is equivalent to doing
 *
 *     ( echo "select " $domainname; echo "use_profile " $profile ) |
 *     /usr/sbin/ccs-loadpolicy -d
 *
 * Caller holds ccs_read_lock().
 */
static int ccs_write_domain_profile(struct ccs_io_buffer *head)
{
        char *data = head->write_buf;
        char *cp = strchr(data, ' ');
        struct ccs_domain_info *domain;
        unsigned int profile;
        if (!cp)
                return -EINVAL;
        *cp = '\0';
        profile = simple_strtoul(data, NULL, 10);
        if (profile >= CCS_MAX_PROFILES)
                return -EINVAL;
        domain = ccs_find_domain(cp + 1);
        if (domain && (!ccs_policy_loaded || ccs_profile_ptr[(u8) profile]))
                domain->profile = (u8) profile;
        return 0;
}

/**
 * ccs_read_domain_profile - Read only domainname and profile.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * This is equivalent to doing
 *
 *     grep -A 1 '^<kernel>' /proc/ccs/domain_policy |
 *     awk ' { if ( domainname == "" ) { if ( $1 == "<kernel>" )
 *     domainname = $0; } else if ( $1 == "use_profile" ) {
 *     print $2 " " domainname; domainname = ""; } } ; '
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_domain_profile(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);
                if (domain->is_deleted)
                        continue;
                if (!ccs_flush(head))
                        return;
                ccs_io_printf(head, "%u ", domain->profile);
                ccs_set_string(head, domain->domainname->name);
                ccs_set_lf(head);
        }
        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 = p->ccs_flags;
        }
        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 "
                              "state[0]=%u state[1]=%u state[2]=%u", pid,
                              ccs_yesno(ccs_flags &
                                        CCS_TASK_IS_MANAGER),
                              ccs_yesno(ccs_flags &
                                        CCS_TASK_IS_EXECUTE_HANDLER),
                              (u8) (ccs_flags >> 24),
                              (u8) (ccs_flags >> 16),
                              (u8) (ccs_flags >> 8));
        }
}

static const char *ccs_transition_type[CCS_MAX_TRANSITION_TYPE] = {
        [CCS_TRANSITION_CONTROL_NO_INITIALIZE]
        = CCS_KEYWORD_NO_INITIALIZE_DOMAIN,
        [CCS_TRANSITION_CONTROL_INITIALIZE] = CCS_KEYWORD_INITIALIZE_DOMAIN,
        [CCS_TRANSITION_CONTROL_NO_KEEP] = CCS_KEYWORD_NO_KEEP_DOMAIN,
        [CCS_TRANSITION_CONTROL_KEEP] = CCS_KEYWORD_KEEP_DOMAIN
};

static const char *ccs_group_name[CCS_MAX_GROUP] = {
        [CCS_PATH_GROUP] = CCS_KEYWORD_PATH_GROUP,
        [CCS_NUMBER_GROUP] = CCS_KEYWORD_NUMBER_GROUP,
        [CCS_ADDRESS_GROUP] = CCS_KEYWORD_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)
{
        char *data = head->write_buf;
        const bool is_delete = ccs_str_starts(&data, CCS_KEYWORD_DELETE);
        u8 i;
        static const struct {
                const char *keyword;
                int (*write) (char *, const bool);
        } ccs_callback[3] = {
                { CCS_KEYWORD_AGGREGATOR, ccs_write_aggregator },
                { CCS_KEYWORD_FILE_PATTERN, ccs_write_pattern },
                { CCS_KEYWORD_DENY_AUTOBIND, ccs_write_reserved_port }
        };
        for (i = 0; i < 3; i++)
                if (ccs_str_starts(&data, ccs_callback[i].keyword))
                        return ccs_callback[i].write(data, is_delete);
        for (i = 0; i < CCS_MAX_TRANSITION_TYPE; i++)
                if (ccs_str_starts(&data, ccs_transition_type[i]))
                        return ccs_write_transition_control(data, is_delete,
                                                            i);
        for (i = 0; i < CCS_MAX_GROUP; i++)
                if (ccs_str_starts(&data, ccs_group_name[i]))
                        return ccs_write_group(data, is_delete, i);
        if (ccs_str_starts(&data, "acl_group ")) {
                unsigned int group;
                if (sscanf(data, "%u", &group) == 1 &&
                    group < CCS_MAX_ACL_GROUPS) {
                        data = strchr(data, ' ');
                        if (data)
                                return ccs_write_domain2(data + 1,
                                                         &ccs_acl_group[group],
                                                         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)
{
        list_for_each_cookie(head->r.group, &ccs_group_list[idx]) {
                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_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);
                                if (member->is_ipv6)
                                        ccs_print_ipv6(buffer, sizeof(buffer),
                                                       member->min.ipv6,
                                                       member->max.ipv6);
                                else
                                        ccs_print_ipv4(buffer, sizeof(buffer),
                                                       member->min.ipv4,
                                                       member->max.ipv4);
                                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)
{
        list_for_each_cookie(head->r.acl, &ccs_policy_list[idx]) {
                struct ccs_acl_head *acl =
                        container_of(head->r.acl, typeof(*acl), list);
                if (acl->is_deleted)
                        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_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_set_string(head, CCS_KEYWORD_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_PATTERN:
                        {
                                struct ccs_pattern *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                ccs_set_string(head, CCS_KEYWORD_FILE_PATTERN);
                                ccs_set_string(head, ptr->pattern->name);
                        }
                        break;
                case CCS_ID_RESERVEDPORT:
                        {
                                struct ccs_reserved *ptr =
                                        container_of(acl, typeof(*ptr), head);
                                const u16 min_port = ptr->min_port;
                                const u16 max_port = ptr->max_port;
                                ccs_set_string(head,
                                               CCS_KEYWORD_DENY_AUTOBIND);
                                ccs_io_printf(head, "%u", min_port);
                                if (min_port != max_port)
                                        ccs_io_printf(head, "-%u", max_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".
 *
 * Caller holds ccs_read_lock().
 */
static void ccs_read_exception(struct ccs_io_buffer *head)
{
        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.group_index = head->r.step - CCS_MAX_POLICY
                        - CCS_MAX_GROUP;
                if (!ccs_read_domain2(head,
                                      &ccs_acl_group[head->r.group_index]))
                        return;
                head->r.step++;
        }
        head->r.eof = true;
}

/* Wait queue for ccs_query_list. */
static DECLARE_WAIT_QUEUE_HEAD(ccs_query_wait);

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

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

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

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

static void ccs_truncate(char *str)
{
        while (* (unsigned char *) str > (unsigned char) ' ')
                str++;
        *str = '\0';
}

/**
 * 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 = -EPERM;
        int pos;
        int len;
        static unsigned int ccs_serial;
        struct ccs_query *entry = NULL;
        bool quota_exceeded = false;
        char *header;
        struct ccs_domain_info * const domain = ccs_current_domain();
        va_start(args, fmt);
        len = vsnprintf((char *) &pos, sizeof(pos) - 1, fmt, args) + 80;
        va_end(args);
        if (r->mode == CCS_CONFIG_LEARNING) {
                char *buffer;
                char *realpath = NULL;
                char *argv0 = NULL;
                char *symlink = NULL;
                char *handler = NULL;
                const struct ccs_preference *pref;
                if (!ccs_domain_quota_ok(r))
                        return 0;
                header = ccs_init_log(&len, r);
                if (!header)
                        return 0;
                pref = &ccs_profile(r->profile)->preference;
                /* strstr() will return NULL if ordering is wrong. */
                if (r->param_type == CCS_TYPE_PATH_ACL &&
                    r->param.path.operation == CCS_TYPE_EXECUTE) {
                        if (pref->learning_exec_argv0) {
                                argv0 = strstr(header, " argv[]={ \"");
                                if (argv0) {
                                        argv0 += 10;
                                        ccs_truncate(argv0);
                                }
                        }
                        if (pref->learning_exec_realpath) {
                                realpath = strstr(header,
                                                  " exec={ realpath=\"");
                                if (realpath) {
                                        realpath += 8;
                                        ccs_truncate(realpath);
                                }
                        }
                } else if (r->param_type == CCS_TYPE_PATH_ACL &&
                           r->param.path.operation == CCS_TYPE_SYMLINK &&
                           pref->learning_symlink_target) {
                        symlink = strstr(header, " symlink.target=\"");
                        if (symlink)
                                ccs_truncate(symlink + 1);
                }
                handler = strstr(header, "type=execute_handler");
                if (handler)
                        ccs_truncate(handler);
                buffer = kmalloc(len, CCS_GFP_FLAGS);
                if (buffer) {
                        va_start(args, fmt);
                        vsnprintf(buffer, len - 1, fmt, args);
                        va_end(args);
                        if (handler || realpath || argv0 || symlink) {
                                ccs_addprintf(buffer, len, " if");
                                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);
                        ccs_write_domain2(buffer, domain, false);
                        kfree(buffer);
                }
                kfree(header);
                return 0;
        }
        if (r->mode != CCS_CONFIG_ENFORCING)
                return 0;
        if (!atomic_read(&ccs_query_observers)) {
                int i;
                if (current->ccs_flags & CCS_DONT_SLEEP_ON_ENFORCE_ERROR)
                        return -EPERM;
                for (i = 0; i < ccs_profile(domain->profile)->preference.
                             enforcing_penalty; i++) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(HZ / 10);
                }
                return -EPERM;
        }
        header = ccs_init_log(&len, r);
        if (!header)
                goto out;
        entry = kzalloc(sizeof(*entry), CCS_GFP_FLAGS);
        if (!entry)
                goto out;
        len = ccs_round2(len);
        entry->query = kzalloc(len, CCS_GFP_FLAGS);
        if (!entry->query)
                goto out;
        spin_lock(&ccs_query_list_lock);
        if (ccs_quota_for_query && ccs_query_memory_size + len +
            sizeof(*entry) >= ccs_quota_for_query) {
                quota_exceeded = true;
        } else {
                ccs_query_memory_size += len + sizeof(*entry);
                entry->serial = ccs_serial++;
        }
        spin_unlock(&ccs_query_list_lock);
        if (quota_exceeded)
                goto out;
        pos = snprintf(entry->query, len - 1, "Q%u-%hu\n%s",
                       entry->serial, r->retry, header);
        kfree(header);
        header = NULL;
        va_start(args, fmt);
        vsnprintf(entry->query + pos, len - 1 - pos, fmt, args);
        entry->query_len = strlen(entry->query) + 1;
        va_end(args);
        spin_lock(&ccs_query_list_lock);
        list_add_tail(&entry->list, &ccs_query_list);
        spin_unlock(&ccs_query_list_lock);
        /* Give 10 seconds for supervisor's opinion. */
        for (entry->timer = 0;
             atomic_read(&ccs_query_observers) && entry->timer < 100;
             entry->timer++) {
                wake_up(&ccs_query_wait);
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(HZ / 10);
                if (entry->answer)
                        break;
        }
        spin_lock(&ccs_query_list_lock);
        list_del(&entry->list);
        ccs_query_memory_size -= len + sizeof(*entry);
        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;
        case 0:
                /* Timed out. */
                break;
        default:
                /* Rejected by administrator. */
                break;
        }
 out:
        if (entry)
                kfree(entry->query);
        kfree(entry);
        kfree(header);
        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".
 */
static void ccs_read_query(struct ccs_io_buffer *head)
{
        struct list_head *tmp;
        int pos = 0;
        int len = 0;
        char *buf;
        if (head->r.w_pos)
                return;
        if (head->read_buf) {
                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, 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)
                        memmove(buf, ptr->query, len);
                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 = answer;
                break;
        }
        spin_unlock(&ccs_query_list_lock);
        return 0;
}

/**
 * ccs_read_version: Get version.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 */
static void ccs_read_version(struct ccs_io_buffer *head)
{
        if (head->r.eof)
                return;
        ccs_set_string(head, "1.8.0-pre");
        head->r.eof = true;
}

/**
 * ccs_read_self_domain - Get the current process's domainname.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 */
static void ccs_read_self_domain(struct ccs_io_buffer *head)
{
        if (head->r.eof)
                return;
        /*
         * ccs_current_domain()->domainname != NULL because every process
         * belongs to a domain and the domain's name cannot be NULL.
         */
        ccs_io_printf(head, "%s", ccs_current_domain()->domainname->name);
        head->r.eof = true;
}

/**
 * ccs_open_control - open() for /proc/ccs/ interface.
 *
 * @type: Type of interface.
 * @file: Pointer to "struct file".
 *
 * Associates policy handler and returns 0 on success, -ENOMEM 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;
        switch (type) {
        case CCS_DOMAINPOLICY: /* /proc/ccs/domain_policy */
                head->write = ccs_write_domain;
                head->read = ccs_read_domain;
                break;
        case CCS_EXCEPTIONPOLICY: /* /proc/ccs/exception_policy */
                head->write = ccs_write_exception;
                head->read = ccs_read_exception;
                break;
#ifdef CONFIG_CCSECURITY_AUDIT
        case CCS_GRANTLOG: /* /proc/ccs/grant_log */
        case CCS_REJECTLOG: /* /proc/ccs/reject_log */
                head->poll = ccs_poll_log;
                head->read = ccs_read_log;
                break;
#endif
        case CCS_SELFDOMAIN: /* /proc/ccs/self_domain */
                head->read = ccs_read_self_domain;
                break;
        case CCS_DOMAIN_STATUS: /* /proc/ccs/.domain_status */
                head->write = ccs_write_domain_profile;
                head->read = ccs_read_domain_profile;
                break;
        case CCS_EXECUTE_HANDLER: /* /proc/ccs/.execute_handler */
                /* Allow execute_handler to read process's status. */
                if (!(current->ccs_flags & CCS_TASK_IS_EXECUTE_HANDLER)) {
                        kfree(head);
                        return -EPERM;
                }
                /* fall through */
        case CCS_PROCESS_STATUS: /* /proc/ccs/.process_status */
                head->write = ccs_write_pid;
                head->read = ccs_read_pid;
                break;
        case CCS_VERSION: /* /proc/ccs/version */
                head->read = ccs_read_version;
                head->readbuf_size = 128;
                break;
        case CCS_MEMINFO: /* /proc/ccs/meminfo */
                head->write = ccs_write_memory_quota;
                head->read = ccs_read_memory_counter;
                head->readbuf_size = 512;
                break;
        case CCS_PROFILE: /* /proc/ccs/profile */
                head->write = ccs_write_profile;
                head->read = ccs_read_profile;
                break;
        case CCS_QUERY: /* /proc/ccs/query */
                head->poll = ccs_poll_query;
                head->write = ccs_write_answer;
                head->read = ccs_read_query;
                break;
        case CCS_MANAGER: /* /proc/ccs/manager */
                head->write = ccs_write_manager;
                head->read = ccs_read_manager;
                break;
        }
        if (!(file->f_mode & FMODE_READ)) {
                /*
                 * No need to allocate read_buf since it is not opened
                 * for reading.
                 */
                head->read = NULL;
                head->poll = NULL;
        } else if (!head->poll) {
                /* Don't allocate read_buf for poll() access. */
                if (!head->readbuf_size)
                        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)) {
                /*
                 * No need to allocate write_buf since it is not opened
                 * for writing.
                 */
                head->write = NULL;
        } else if (head->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 (type != CCS_QUERY &&
            type != CCS_GRANTLOG && type != CCS_REJECTLOG)
                head->reader_idx = ccs_lock();
        file->private_data = head;
        /*
         * Call the handler now if the file is /proc/ccs/self_domain
         * so that the user can use "cat < /proc/ccs/self_domain" to
         * know the current process's domainname.
         */
        if (type == CCS_SELFDOMAIN)
                ccs_read_control(file, NULL, 0);
        /*
         * 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.
         */
        else if (