security/ccsecurity/network.c

/*
 * fs/tomoyo_network.c
 *
 * Implementation of the Domain-Based Mandatory Access Control.
 *
 * Copyright (C) 2005-2009  NTT DATA CORPORATION
 *
 * Version: 1.6.7+   2009/04/20
 *
 * This file is applicable to both 2.4.30 and 2.6.11 and later.
 * See README.ccs for ChangeLog.
 *
 */

#include <linux/ccs_common.h>
#include <linux/tomoyo.h>
#include <linux/tomoyo_socket.h>
#include <linux/realpath.h>
#include <linux/net.h>
#include <linux/inet.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/udp.h>

/* Index numbers for Network Controls. */
enum ccs_network_acl_index {
        NETWORK_ACL_UDP_BIND,
        NETWORK_ACL_UDP_CONNECT,
        NETWORK_ACL_TCP_BIND,
        NETWORK_ACL_TCP_LISTEN,
        NETWORK_ACL_TCP_CONNECT,
        NETWORK_ACL_TCP_ACCEPT,
        NETWORK_ACL_RAW_BIND,
        NETWORK_ACL_RAW_CONNECT
};

/**
 * ccs_audit_network_log - Audit network log.
 *
 * @r:          Pointer to "struct ccs_request_info".
 * @operation:  The name of operation.
 * @address:    An IPv4 or IPv6 address.
 * @port:       Port number.
 * @is_granted: True if this is a granted log.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_audit_network_log(struct ccs_request_info *r,
                                 const char *operation, const char *address,
                                 const u16 port, const bool is_granted)
{
        return ccs_write_audit_log(is_granted, r, KEYWORD_ALLOW_NETWORK
                                   "%s %s %u\n", operation, address, port);
}

/**
 * ccs_save_ipv6_address - Keep the given IPv6 address on the RAM.
 *
 * @addr: Pointer to "struct in6_addr".
 *
 * Returns pointer to "struct in6_addr" on success, NULL otherwise.
 *
 * The RAM is shared, so NEVER try to modify or kfree() the returned address.
 */
static const struct in6_addr *ccs_save_ipv6_address(const struct in6_addr *addr)
{
        static const u8 ccs_block_size = 16;
        struct ccs_addr_list {
                /* Workaround for gcc 4.3's bug. */
                struct in6_addr addr[16]; /* = ccs_block_size */
                struct list1_head list;
                u32 in_use_count;
        };
        static LIST1_HEAD(ccs_address_list);
        struct ccs_addr_list *ptr;
        static DEFINE_MUTEX(lock);
        u8 i = ccs_block_size;
        if (!addr)
                return NULL;
        mutex_lock(&lock);
        list1_for_each_entry(ptr, &ccs_address_list, list) {
                for (i = 0; i < ptr->in_use_count; i++) {
                        if (!memcmp(&ptr->addr[i], addr, sizeof(*addr)))
                                goto ok;
                }
                if (i < ccs_block_size)
                        break;
        }
        if (i == ccs_block_size) {
                ptr = ccs_alloc_element(sizeof(*ptr));
                if (!ptr)
                        goto ok;
                list1_add_tail_mb(&ptr->list, &ccs_address_list);
                i = 0;
        }
        ptr->addr[ptr->in_use_count++] = *addr;
 ok:
        mutex_unlock(&lock);
        return ptr ? &ptr->addr[i] : NULL;
}

/* The list for "struct ccs_address_group_entry". */
static LIST1_HEAD(ccs_address_group_list);

/**
 * ccs_update_address_group_entry - Update "struct ccs_address_group_entry" list.
 *
 * @group_name:  The name of address group.
 * @is_ipv6:     True if @min_address and @max_address are IPv6 addresses.
 * @min_address: Start of IPv4 or IPv6 address range.
 * @max_address: End of IPv4 or IPv6 address range.
 * @is_delete:   True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_update_address_group_entry(const char *group_name,
                                          const bool is_ipv6,
                                          const u16 *min_address,
                                          const u16 *max_address,
                                          const bool is_delete)
{
        static DEFINE_MUTEX(lock);
        struct ccs_address_group_entry *new_group;
        struct ccs_address_group_entry *group;
        struct ccs_address_group_member *new_member;
        struct ccs_address_group_member *member;
        const struct ccs_path_info *saved_group_name;
        const struct in6_addr *saved_min_address = NULL;
        const struct in6_addr *saved_max_address = NULL;
        int error = -ENOMEM;
        bool found = false;
        const u32 min_ipv4_address = ntohl(*(u32 *) min_address);
        const u32 max_ipv4_address = ntohl(*(u32 *) max_address);
        if (!ccs_is_correct_path(group_name, 0, 0, 0, __func__) ||
            !group_name[0])
                return -EINVAL;
        saved_group_name = ccs_save_name(group_name);
        if (!saved_group_name)
                return -ENOMEM;
        if (!is_ipv6)
                goto not_ipv6;
        saved_min_address
                = ccs_save_ipv6_address((struct in6_addr *) min_address);
        saved_max_address
                = ccs_save_ipv6_address((struct in6_addr *) max_address);
        if (!saved_min_address || !saved_max_address)
                return -ENOMEM;
 not_ipv6:
        mutex_lock(&lock);
        list1_for_each_entry(group, &ccs_address_group_list, list) {
                if (saved_group_name != group->group_name)
                        continue;
                list1_for_each_entry(member, &group->address_group_member_list,
                                     list) {
                        if (member->is_ipv6 != is_ipv6)
                                continue;
                        if (is_ipv6) {
                                if (member->min.ipv6 != saved_min_address ||
                                    member->max.ipv6 != saved_max_address)
                                        continue;
                        } else {
                                if (member->min.ipv4 != min_ipv4_address ||
                                    member->max.ipv4 != max_ipv4_address)
                                        continue;
                        }
                        member->is_deleted = is_delete;
                        error = 0;
                        goto out;
                }
                found = true;
                break;
        }
        if (is_delete) {
                error = -ENOENT;
                goto out;
        }
        if (!found) {
                new_group = ccs_alloc_element(sizeof(*new_group));
                if (!new_group)
                        goto out;
                INIT_LIST1_HEAD(&new_group->address_group_member_list);
                new_group->group_name = saved_group_name;
                list1_add_tail_mb(&new_group->list, &ccs_address_group_list);
                group = new_group;
        }
        new_member = ccs_alloc_element(sizeof(*new_member));
        if (!new_member)
                goto out;
        new_member->is_ipv6 = is_ipv6;
        if (is_ipv6) {
                new_member->min.ipv6 = saved_min_address;
                new_member->max.ipv6 = saved_max_address;
        } else {
                new_member->min.ipv4 = min_ipv4_address;
                new_member->max.ipv4 = max_ipv4_address;
        }
        list1_add_tail_mb(&new_member->list, &group->address_group_member_list);
        error = 0;
 out:
        mutex_unlock(&lock);
        ccs_update_counter(CCS_UPDATES_COUNTER_EXCEPTION_POLICY);
        return error;
}

/**
 * ccs_parse_ip_address - Parse an IP address.
 *
 * @address: String to parse.
 * @min:     Pointer to store min address.
 * @max:     Pointer to store max address.
 *
 * Returns 2 if @address is an IPv6, 1 if @address is an IPv4, 0 otherwise.
 */
static int ccs_parse_ip_address(char *address, u16 *min, u16 *max)
{
        int count = sscanf(address, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx"
                           "-%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx",
                           &min[0], &min[1], &min[2], &min[3],
                           &min[4], &min[5], &min[6], &min[7],
                           &max[0], &max[1], &max[2], &max[3],
                           &max[4], &max[5], &max[6], &max[7]);
        if (count == 8 || count == 16) {
                u8 i;
                if (count == 8)
                        memmove(max, min, sizeof(u16) * 8);
                for (i = 0; i < 8; i++) {
                        min[i] = htons(min[i]);
                        max[i] = htons(max[i]);
                }
                return 2;
        }
        count = sscanf(address, "%hu.%hu.%hu.%hu-%hu.%hu.%hu.%hu",
                       &min[0], &min[1], &min[2], &min[3],
                       &max[0], &max[1], &max[2], &max[3]);
        if (count == 4 || count == 8) {
                u32 ip = htonl((((u8) min[0]) << 24) + (((u8) min[1]) << 16)
                               + (((u8) min[2]) << 8) + (u8) min[3]);
                memmove(min, &ip, sizeof(ip));
                if (count == 8)
                        ip = htonl((((u8) max[0]) << 24) + (((u8) max[1]) << 16)
                                   + (((u8) max[2]) << 8) + (u8) max[3]);
                memmove(max, &ip, sizeof(ip));
                return 1;
        }
        return 0;
}

/**
 * ccs_write_address_group_policy - Write "struct ccs_address_group_entry" list.
 *
 * @data:      String to parse.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
int ccs_write_address_group_policy(char *data, const bool is_delete)
{
        bool is_ipv6;
        u16 min_address[8];
        u16 max_address[8];
        char *cp = strchr(data, ' ');
        if (!cp)
                return -EINVAL;
        *cp++ = '\0';
        switch (ccs_parse_ip_address(cp, min_address, max_address)) {
        case 2:
                is_ipv6 = true;
                break;
        case 1:
                is_ipv6 = false;
                break;
        default:
                return -EINVAL;
        }
        return ccs_update_address_group_entry(data, is_ipv6, min_address,
                                              max_address, is_delete);
}

/**
 * ccs_find_or_assign_new_address_group - Create address group.
 *
 * @group_name: The name of address group.
 *
 * Returns pointer to "struct ccs_address_group_entry" on success,
 * NULL otherwise.
 */
static struct ccs_address_group_entry *
ccs_find_or_assign_new_address_group(const char *group_name)
{
        u8 i;
        struct ccs_address_group_entry *group;
        for (i = 0; i <= 1; i++) {
                list1_for_each_entry(group, &ccs_address_group_list, list) {
                        if (!strcmp(group_name, group->group_name->name))
                                return group;
                }
                if (!i) {
                        const u16 dummy[2] = { 0, 0 };
                        ccs_update_address_group_entry(group_name, false,
                                                       dummy, dummy, false);
                        ccs_update_address_group_entry(group_name, false,
                                                       dummy, dummy, true);
                }
        }
        return NULL;
}

/**
 * ccs_address_matches_group - Check whether the given address matches members of the given address group.
 *
 * @is_ipv6: True if @address is an IPv6 address.
 * @address: An IPv4 or IPv6 address.
 * @group:   Pointer to "struct ccs_address_group_entry".
 *
 * Returns true if @address matches addresses in @group group, false otherwise.
 */
static bool ccs_address_matches_group(const bool is_ipv6, const u32 *address,
                                      const struct ccs_address_group_entry *
                                      group)
{
        struct ccs_address_group_member *member;
        const u32 ip = ntohl(*address);
        list1_for_each_entry(member, &group->address_group_member_list, list) {
                if (member->is_deleted)
                        continue;
                if (member->is_ipv6) {
                        if (is_ipv6 &&
                            memcmp(member->min.ipv6, address, 16) <= 0 &&
                            memcmp(address, member->max.ipv6, 16) <= 0)
                                return true;
                } else {
                        if (!is_ipv6 &&
                            member->min.ipv4 <= ip && ip <= member->max.ipv4)
                                return true;
                }
        }
        return false;
}

/**
 * ccs_read_address_group_policy - Read "struct ccs_address_group_entry" list.
 *
 * @head: Pointer to "struct ccs_io_buffer".
 *
 * Returns true on success, false otherwise.
 */
bool ccs_read_address_group_policy(struct ccs_io_buffer *head)
{
        struct list1_head *gpos;
        struct list1_head *mpos;
        list1_for_each_cookie(gpos, head->read_var1, &ccs_address_group_list) {
                struct ccs_address_group_entry *group;
                group = list1_entry(gpos, struct ccs_address_group_entry, list);
                list1_for_each_cookie(mpos, head->read_var2,
                                      &group->address_group_member_list) {
                        char buf[128];
                        struct ccs_address_group_member *member;
                        member = list1_entry(mpos,
                                             struct ccs_address_group_member,
                                             list);
                        if (member->is_deleted)
                                continue;
                        if (member->is_ipv6) {
                                const struct in6_addr *min_address
                                        = member->min.ipv6;
                                const struct in6_addr *max_address
                                        = member->max.ipv6;
                                ccs_print_ipv6(buf, sizeof(buf), min_address);
                                if (min_address != max_address) {
                                        int len;
                                        char *cp = buf + strlen(buf);
                                        *cp++ = '-';
                                        len = strlen(buf);
                                        ccs_print_ipv6(cp, sizeof(buf) - len,
                                                       max_address);
                                }
                        } else {
                                const u32 min_address = member->min.ipv4;
                                const u32 max_address = member->max.ipv4;
                                memset(buf, 0, sizeof(buf));
                                snprintf(buf, sizeof(buf) - 1, "%u.%u.%u.%u",
                                         HIPQUAD(min_address));
                                if (min_address != max_address) {
                                        const int len = strlen(buf);
                                        snprintf(buf + len,
                                                 sizeof(buf) - 1 - len,
                                                 "-%u.%u.%u.%u",
                                                 HIPQUAD(max_address));
                                }
                        }
                        if (!ccs_io_printf(head, KEYWORD_ADDRESS_GROUP
                                           "%s %s\n", group->group_name->name,
                                           buf))
                                goto out;
                }
        }
        return true;
 out:
        return false;
}

#if !defined(NIP6)
#define NIP6(addr)      \
        ntohs((addr).s6_addr16[0]), ntohs((addr).s6_addr16[1]), \
        ntohs((addr).s6_addr16[2]), ntohs((addr).s6_addr16[3]), \
        ntohs((addr).s6_addr16[4]), ntohs((addr).s6_addr16[5]), \
        ntohs((addr).s6_addr16[6]), ntohs((addr).s6_addr16[7])
#endif

/**
 * ccs_print_ipv6 - Print an IPv6 address.
 *
 * @buffer:     Buffer to write to.
 * @buffer_len: Size of @buffer.
 * @ip:         Pointer to "struct in6_addr".
 *
 * Returns nothing.
 */
void ccs_print_ipv6(char *buffer, const int buffer_len,
                    const struct in6_addr *ip)
{
        memset(buffer, 0, buffer_len);
        snprintf(buffer, buffer_len - 1, "%x:%x:%x:%x:%x:%x:%x:%x", NIP6(*ip));
}

/**
 * ccs_net2keyword - Convert network operation index to network operation name.
 *
 * @operation: Type of operation.
 *
 * Returns the name of operation.
 */
const char *ccs_net2keyword(const u8 operation)
{
        const char *keyword = "unknown";
        switch (operation) {
        case NETWORK_ACL_UDP_BIND:
                keyword = "UDP bind";
                break;
        case NETWORK_ACL_UDP_CONNECT:
                keyword = "UDP connect";
                break;
        case NETWORK_ACL_TCP_BIND:
                keyword = "TCP bind";
                break;
        case NETWORK_ACL_TCP_LISTEN:
                keyword = "TCP listen";
                break;
        case NETWORK_ACL_TCP_CONNECT:
                keyword = "TCP connect";
                break;
        case NETWORK_ACL_TCP_ACCEPT:
                keyword = "TCP accept";
                break;
        case NETWORK_ACL_RAW_BIND:
                keyword = "RAW bind";
                break;
        case NETWORK_ACL_RAW_CONNECT:
                keyword = "RAW connect";
                break;
        }
        return keyword;
}

/**
 * ccs_update_network_entry - Update "struct ccs_ip_network_acl_record" list.
 *
 * @operation:   Type of operation.
 * @record_type: Type of address.
 * @group:       Pointer to "struct ccs_address_group_entry". May be NULL.
 * @min_address: Start of IPv4 or IPv6 address range.
 * @max_address: End of IPv4 or IPv6 address range.
 * @min_port:    Start of port number range.
 * @max_port:    End of port number range.
 * @domain:      Pointer to "struct ccs_domain_info".
 * @condition:   Pointer to "struct ccs_condition_list". May be NULL.
 * @is_delete:   True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_update_network_entry(const u8 operation, const u8 record_type,
                                    const struct ccs_address_group_entry *group,
                                    const u32 *min_address,
                                    const u32 *max_address,
                                    const u16 min_port, const u16 max_port,
                                    struct ccs_domain_info *domain,
                                    const struct ccs_condition_list *condition,
                                    const bool is_delete)
{
        static DEFINE_MUTEX(lock);
        struct ccs_acl_info *ptr;
        struct ccs_ip_network_acl_record *acl;
        int error = -ENOMEM;
        /* using host byte order to allow u32 comparison than memcmp().*/
        const u32 min_ip = ntohl(*min_address);
        const u32 max_ip = ntohl(*max_address);
        const struct in6_addr *saved_min_address = NULL;
        const struct in6_addr *saved_max_address = NULL;
        if (!domain)
                return -EINVAL;
        if (record_type != IP_RECORD_TYPE_IPv6)
                goto not_ipv6;
        saved_min_address = ccs_save_ipv6_address((struct in6_addr *)
                                                  min_address);
        saved_max_address = ccs_save_ipv6_address((struct in6_addr *)
                                                  max_address);
        if (!saved_min_address || !saved_max_address)
                return -ENOMEM;
 not_ipv6:
        mutex_lock(&lock);
        if (is_delete)
                goto delete;
        list1_for_each_entry(ptr, &domain->acl_info_list, list) {
                if (ccs_acl_type1(ptr) != TYPE_IP_NETWORK_ACL)
                        continue;
                if (ccs_get_condition_part(ptr) != condition)
                        continue;
                acl = container_of(ptr, struct ccs_ip_network_acl_record, head);
                if (acl->operation_type != operation ||
                    acl->record_type != record_type ||
                    acl->min_port != min_port || max_port != acl->max_port)
                        continue;
                if (record_type == IP_RECORD_TYPE_ADDRESS_GROUP) {
                        if (acl->u.group != group)
                                continue;
                } else if (record_type == IP_RECORD_TYPE_IPv4) {
                        if (acl->u.ipv4.min != min_ip ||
                            max_ip != acl->u.ipv4.max)
                                continue;
                } else if (record_type == IP_RECORD_TYPE_IPv6) {
                        if (acl->u.ipv6.min != saved_min_address ||
                            saved_max_address != acl->u.ipv6.max)
                                continue;
                }
                error = ccs_add_domain_acl(NULL, ptr);
                goto out;
        }
        /* Not found. Append it to the tail. */
        acl = ccs_alloc_acl_element(TYPE_IP_NETWORK_ACL, condition);
        if (!acl)
                goto out;
        acl->operation_type = operation;
        acl->record_type = record_type;
        if (record_type == IP_RECORD_TYPE_ADDRESS_GROUP) {
                acl->u.group = group;
        } else if (record_type == IP_RECORD_TYPE_IPv4) {
                acl->u.ipv4.min = min_ip;
                acl->u.ipv4.max = max_ip;
        } else {
                acl->u.ipv6.min = saved_min_address;
                acl->u.ipv6.max = saved_max_address;
        }
        acl->min_port = min_port;
        acl->max_port = max_port;
        error = ccs_add_domain_acl(domain, &acl->head);
        goto out;
 delete:
        error = -ENOENT;
        list1_for_each_entry(ptr, &domain->acl_info_list, list) {
                if (ccs_acl_type2(ptr) != TYPE_IP_NETWORK_ACL)
                        continue;
                if (ccs_get_condition_part(ptr) != condition)
                        continue;
                acl = container_of(ptr, struct ccs_ip_network_acl_record, head);
                if (acl->operation_type != operation ||
                    acl->record_type != record_type ||
                    acl->min_port != min_port || max_port != acl->max_port)
                        continue;
                if (record_type == IP_RECORD_TYPE_ADDRESS_GROUP) {
                        if (acl->u.group != group)
                                continue;
                } else if (record_type == IP_RECORD_TYPE_IPv4) {
                        if (acl->u.ipv4.min != min_ip ||
                            max_ip != acl->u.ipv4.max)
                                continue;
                } else if (record_type == IP_RECORD_TYPE_IPv6) {
                        if (acl->u.ipv6.min != saved_min_address ||
                            saved_max_address != acl->u.ipv6.max)
                                continue;
                }
                error = ccs_del_domain_acl(ptr);
                break;
        }
 out:
        mutex_unlock(&lock);
        return error;
}

/**
 * ccs_check_network_entry - Check permission for network operation.
 *
 * @is_ipv6:   True if @address is an IPv6 address.
 * @operation: Type of operation.
 * @address:   An IPv4 or IPv6 address.
 * @port:      Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_check_network_entry(const bool is_ipv6, const u8 operation,
                                   const u32 *address, const u16 port)
{
        struct ccs_request_info r;
        struct ccs_acl_info *ptr;
        const char *keyword = ccs_net2keyword(operation);
        bool is_enforce;
        /* using host byte order to allow u32 comparison than memcmp().*/
        const u32 ip = ntohl(*address);
        bool found = false;
        char buf[64];
        if (!ccs_can_sleep())
                return 0;
        ccs_init_request_info(&r, NULL, CCS_MAC_FOR_NETWORK);
        is_enforce = (r.mode == 3);
        if (!r.mode)
                return 0;
 retry:
        list1_for_each_entry(ptr, &r.domain->acl_info_list, list) {
                struct ccs_ip_network_acl_record *acl;
                if (ccs_acl_type2(ptr) != TYPE_IP_NETWORK_ACL)
                        continue;
                acl = container_of(ptr, struct ccs_ip_network_acl_record, head);
                if (acl->operation_type != operation || port < acl->min_port ||
                    acl->max_port < port || !ccs_check_condition(&r, ptr))
                        continue;
                if (acl->record_type == IP_RECORD_TYPE_ADDRESS_GROUP) {
                        if (!ccs_address_matches_group(is_ipv6, address,
                                                       acl->u.group))
                                continue;
                } else if (acl->record_type == IP_RECORD_TYPE_IPv4) {
                        if (is_ipv6 ||
                            ip < acl->u.ipv4.min || acl->u.ipv4.max < ip)
                                continue;
                } else {
                        if (!is_ipv6 ||
                            memcmp(acl->u.ipv6.min, address, 16) > 0 ||
                            memcmp(address, acl->u.ipv6.max, 16) > 0)
                                continue;
                }
                r.cond = ccs_get_condition_part(ptr);
                found = true;
                break;
        }
        memset(buf, 0, sizeof(buf));
        if (is_ipv6)
                ccs_print_ipv6(buf, sizeof(buf),
                               (const struct in6_addr *) address);
        else
                snprintf(buf, sizeof(buf) - 1, "%u.%u.%u.%u", HIPQUAD(ip));
        ccs_audit_network_log(&r, keyword, buf, port, found);
        if (found)
                return 0;
        if (ccs_verbose_mode(r.domain))
                printk(KERN_WARNING "TOMOYO-%s: %s to %s %u denied for %s\n",
                       ccs_get_msg(is_enforce), keyword, buf, port,
                       ccs_get_last_name(r.domain));
        if (is_enforce) {
                int error = ccs_check_supervisor(&r, KEYWORD_ALLOW_NETWORK
                                                 "%s %s %u\n", keyword, buf,
                                                 port);
                if (error == 1)
                        goto retry;
                return error;
        }
        if (r.mode == 1 && ccs_domain_quota_ok(r.domain))
                ccs_update_network_entry(operation, is_ipv6 ?
                                         IP_RECORD_TYPE_IPv6 :
                                         IP_RECORD_TYPE_IPv4,
                                         NULL, address, address, port, port,
                                         r.domain, ccs_handler_cond(), 0);
        return 0;
}

/**
 * ccs_write_network_policy - Write "struct ccs_ip_network_acl_record" list.
 *
 * @data:      String to parse.
 * @domain:    Pointer to "struct ccs_domain_info".
 * @condition: Pointer to "struct ccs_condition_list". May be NULL.
 * @is_delete: True if it is a delete request.
 *
 * Returns 0 on success, negative value otherwise.
 */
int ccs_write_network_policy(char *data, struct ccs_domain_info *domain,
                             const struct ccs_condition_list *condition,
                             const bool is_delete)
{
        u8 sock_type;
        u8 operation;
        u8 record_type;
        u16 min_address[8];
        u16 max_address[8];
        struct ccs_address_group_entry *group = NULL;
        u16 min_port;
        u16 max_port;
        u8 count;
        char *cp1 = strchr(data, ' ');
        char *cp2;
        if (!cp1)
                goto out;
        cp1++;
        if (!strncmp(data, "TCP ", 4))
                sock_type = SOCK_STREAM;
        else if (!strncmp(data, "UDP ", 4))
                sock_type = SOCK_DGRAM;
        else if (!strncmp(data, "RAW ", 4))
                sock_type = SOCK_RAW;
        else
                goto out;
        cp2 = strchr(cp1, ' ');
        if (!cp2)
                goto out;
        cp2++;
        if (!strncmp(cp1, "bind ", 5))
                switch (sock_type) {
                case SOCK_STREAM:
                        operation = NETWORK_ACL_TCP_BIND;
                        break;
                case SOCK_DGRAM:
                        operation = NETWORK_ACL_UDP_BIND;
                        break;
                default:
                        operation = NETWORK_ACL_RAW_BIND;
                }
        else if (!strncmp(cp1, "connect ", 8))
                switch (sock_type) {
                case SOCK_STREAM:
                        operation = NETWORK_ACL_TCP_CONNECT;
                        break;
                case SOCK_DGRAM:
                        operation = NETWORK_ACL_UDP_CONNECT;
                        break;
                default:
                        operation = NETWORK_ACL_RAW_CONNECT;
                }
        else if (sock_type == SOCK_STREAM && !strncmp(cp1, "listen ", 7))
                operation = NETWORK_ACL_TCP_LISTEN;
        else if (sock_type == SOCK_STREAM && !strncmp(cp1, "accept ", 7))
                operation = NETWORK_ACL_TCP_ACCEPT;
        else
                goto out;
        cp1 = strchr(cp2, ' ');
        if (!cp1)
                goto out;
        *cp1++ = '\0';
        switch (ccs_parse_ip_address(cp2, min_address, max_address)) {
        case 2:
                record_type = IP_RECORD_TYPE_IPv6;
                break;
        case 1:
                record_type = IP_RECORD_TYPE_IPv4;
                break;
        default:
                if (*cp2 != '@')
                        goto out;
                group = ccs_find_or_assign_new_address_group(cp2 + 1);
                if (!group)
                        return -ENOMEM;
                record_type = IP_RECORD_TYPE_ADDRESS_GROUP;
                break;
        }
        if (strchr(cp1, ' '))
                goto out;
        count = sscanf(cp1, "%hu-%hu", &min_port, &max_port);
        if (count != 1 && count != 2)
                goto out;
        if (count == 1)
                max_port = min_port;
        return ccs_update_network_entry(operation, record_type, group,
                                        (u32 *) min_address,
                                        (u32 *) max_address,
                                        min_port, max_port, domain, condition,
                                        is_delete);
 out:
        return -EINVAL;
}

/**
 * ccs_check_network_listen_acl - Check permission for listen() operation.
 *
 * @is_ipv6: True if @address is an IPv6 address.
 * @address: An IPv4 or IPv6 address.
 * @port:    Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_check_network_listen_acl(const bool is_ipv6,
                                               const u8 *address,
                                               const u16 port)
{
        return ccs_check_network_entry(is_ipv6, NETWORK_ACL_TCP_LISTEN,
                                       (const u32 *) address, ntohs(port));
}

/**
 * ccs_check_network_connect_acl - Check permission for connect() operation.
 *
 * @is_ipv6:   True if @address is an IPv6 address.
 * @sock_type: Type of socket. (TCP or UDP or RAW)
 * @address:   An IPv4 or IPv6 address.
 * @port:      Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_check_network_connect_acl(const bool is_ipv6,
                                                const int sock_type,
                                                const u8 *address,
                                                const u16 port)
{
        u8 operation;
        switch (sock_type) {
        case SOCK_STREAM:
                operation = NETWORK_ACL_TCP_CONNECT;
                break;
        case SOCK_DGRAM:
                operation = NETWORK_ACL_UDP_CONNECT;
                break;
        default:
                operation = NETWORK_ACL_RAW_CONNECT;
        }
        return ccs_check_network_entry(is_ipv6, operation,
                                       (const u32 *) address, ntohs(port));
}

/**
 * ccs_check_network_bind_acl - Check permission for bind() operation.
 *
 * @is_ipv6:   True if @address is an IPv6 address.
 * @sock_type: Type of socket. (TCP or UDP or RAW)
 * @address:   An IPv4 or IPv6 address.
 * @port:      Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static int ccs_check_network_bind_acl(const bool is_ipv6, const int sock_type,
                                      const u8 *address, const u16 port)
{
        u8 operation;
        switch (sock_type) {
        case SOCK_STREAM:
                operation = NETWORK_ACL_TCP_BIND;
                break;
        case SOCK_DGRAM:
                operation = NETWORK_ACL_UDP_BIND;
                break;
        default:
                operation = NETWORK_ACL_RAW_BIND;
        }
        return ccs_check_network_entry(is_ipv6, operation,
                                       (const u32 *) address, ntohs(port));
}

/**
 * ccs_check_network_accept_acl - Check permission for accept() operation.
 *
 * @is_ipv6: True if @address is an IPv6 address.
 * @address: An IPv4 or IPv6 address.
 * @port:    Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_check_network_accept_acl(const bool is_ipv6,
                                               const u8 *address,
                                               const u16 port)
{
        int retval;
        current->ccs_flags |= CCS_DONT_SLEEP_ON_ENFORCE_ERROR;
        retval = ccs_check_network_entry(is_ipv6, NETWORK_ACL_TCP_ACCEPT,
                                         (const u32 *) address, ntohs(port));
        current->ccs_flags &= ~CCS_DONT_SLEEP_ON_ENFORCE_ERROR;
        return retval;
}

/**
 * ccs_check_network_sendmsg_acl - Check permission for sendmsg() operation.
 *
 * @is_ipv6:   True if @address is an IPv6 address.
 * @sock_type: Type of socket. (UDP or RAW)
 * @address:   An IPv4 or IPv6 address.
 * @port:      Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_check_network_sendmsg_acl(const bool is_ipv6,
                                                const int sock_type,
                                                const u8 *address,
                                                const u16 port)
{
        u8 operation;
        if (sock_type == SOCK_DGRAM)
                operation = NETWORK_ACL_UDP_CONNECT;
        else
                operation = NETWORK_ACL_RAW_CONNECT;
        return ccs_check_network_entry(is_ipv6, operation,
                                       (const u32 *) address, ntohs(port));
}

/**
 * ccs_check_network_recvmsg_acl - Check permission for recvmsg() operation.
 *
 * @is_ipv6:   True if @address is an IPv6 address.
 * @sock_type: Type of socket. (UDP or RAW)
 * @address:   An IPv4 or IPv6 address.
 * @port:      Port number.
 *
 * Returns 0 on success, negative value otherwise.
 */
static inline int ccs_check_network_recvmsg_acl(const bool is_ipv6,
                                                const int sock_type,
                                                const u8 *address,
                                                const u16 port)
{
        int retval;
        const u8 operation
                = (sock_type == SOCK_DGRAM) ?
                NETWORK_ACL_UDP_CONNECT : NETWORK_ACL_RAW_CONNECT;
        current->ccs_flags |= CCS_DONT_SLEEP_ON_ENFORCE_ERROR;
        retval = ccs_check_network_entry(is_ipv6, operation,
                                         (const u32 *) address, ntohs(port));
        current->ccs_flags &= ~CCS_DONT_SLEEP_ON_ENFORCE_ERROR;
        return retval;
}

#define MAX_SOCK_ADDR 128 /* net/socket.c */

/* Check permission for creating a socket. */
int ccs_socket_create_permission(int family, int type, int protocol)
{
        int error = 0;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        if (family == PF_PACKET && !ccs_capable(CCS_USE_PACKET_SOCKET))
                return -EPERM;
        if (family == PF_ROUTE && !ccs_capable(CCS_USE_ROUTE_SOCKET))
                return -EPERM;
        if (family != PF_INET && family != PF_INET6)
                return 0;
        switch (type) {
        case SOCK_STREAM:
                if (!ccs_capable(CCS_INET_STREAM_SOCKET_CREATE))
                        error = -EPERM;
                break;
        case SOCK_DGRAM:
                if (!ccs_capable(CCS_USE_INET_DGRAM_SOCKET))
                        error = -EPERM;
                break;
        case SOCK_RAW:
                if (!ccs_capable(CCS_USE_INET_RAW_SOCKET))
                        error = -EPERM;
                break;
        }
        return error;
}

/* Check permission for listening a TCP socket. */
int ccs_socket_listen_permission(struct socket *sock)
{
        int error = 0;
        char addr[MAX_SOCK_ADDR];
        int addr_len;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        if (sock->type != SOCK_STREAM)
                return 0;
        switch (sock->sk->sk_family) {
        case PF_INET:
        case PF_INET6:
                break;
        default:
                return 0;
        }
        if (!ccs_capable(CCS_INET_STREAM_SOCKET_LISTEN))
                return -EPERM;
        if (sock->ops->getname(sock, (struct sockaddr *) addr, &addr_len, 0))
                return -EPERM;
        switch (((struct sockaddr *) addr)->sa_family) {
                struct sockaddr_in6 *addr6;
                struct sockaddr_in *addr4;
        case AF_INET6:
                addr6 = (struct sockaddr_in6 *) addr;
                error = ccs_check_network_listen_acl(true,
                                                     addr6->sin6_addr.s6_addr,
                                                     addr6->sin6_port);
                break;
        case AF_INET:
                addr4 = (struct sockaddr_in *) addr;
                error = ccs_check_network_listen_acl(false,
                                                     (u8 *) &addr4->sin_addr,
                                                     addr4->sin_port);
                break;
        }
        return error;
}

/* Check permission for setting the remote IP address/port pair of a socket. */
int ccs_socket_connect_permission(struct socket *sock, struct sockaddr *addr,
                                  int addr_len)
{
        int error = 0;
        const unsigned int type = sock->type;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        switch (type) {
        case SOCK_STREAM:
        case SOCK_DGRAM:
        case SOCK_RAW:
                break;
        default:
                return 0;
        }
        switch (addr->sa_family) {
                struct sockaddr_in6 *addr6;
                struct sockaddr_in *addr4;
                u16 port;
        case AF_INET6:
                if (addr_len < SIN6_LEN_RFC2133)
                        break;
                addr6 = (struct sockaddr_in6 *) addr;
                if (type != SOCK_RAW)
                        port = addr6->sin6_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_connect_acl(true, type,
                                                      addr6->sin6_addr.s6_addr,
                                                      port);
                break;
        case AF_INET:
                if (addr_len < sizeof(struct sockaddr_in))
                        break;
                addr4 = (struct sockaddr_in *) addr;
                if (type != SOCK_RAW)
                        port = addr4->sin_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_connect_acl(false, type,
                                                      (u8 *) &addr4->sin_addr,
                                                      port);
                break;
        }
        if (type != SOCK_STREAM)
                return error;
        switch (sock->sk->sk_family) {
        case PF_INET:
        case PF_INET6:
                if (!ccs_capable(CCS_INET_STREAM_SOCKET_CONNECT))
                        error = -EPERM;
                break;
        }
        return error;
}

/* Check permission for setting the local IP address/port pair of a socket. */
int ccs_socket_bind_permission(struct socket *sock, struct sockaddr *addr,
                               int addr_len)
{
        int error = 0;
        const unsigned int type = sock->type;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        switch (type) {
        case SOCK_STREAM:
        case SOCK_DGRAM:
        case SOCK_RAW:
                break;
        default:
                return 0;
        }
        switch (addr->sa_family) {
                struct sockaddr_in6 *addr6;
                struct sockaddr_in *addr4;
                u16 port;
        case AF_INET6:
                if (addr_len < SIN6_LEN_RFC2133)
                        break;
                addr6 = (struct sockaddr_in6 *) addr;
                if (type != SOCK_RAW)
                        port = addr6->sin6_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_bind_acl(true, type,
                                                   addr6->sin6_addr.s6_addr,
                                                   port);
                break;
        case AF_INET:
                if (addr_len < sizeof(struct sockaddr_in))
                        break;
                addr4 = (struct sockaddr_in *) addr;
                if (type != SOCK_RAW)
                        port = addr4->sin_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_bind_acl(false, type,
                                                   (u8 *) &addr4->sin_addr,
                                                   port);
                break;
        }
        return error;
}

/*
 * Check permission for accepting a TCP socket.
 *
 * Currently, the LSM hook for this purpose is not provided.
 */
int ccs_socket_accept_permission(struct socket *sock, struct sockaddr *addr)
{
        int error = 0;
        int addr_len;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        switch (sock->sk->sk_family) {
        case PF_INET:
        case PF_INET6:
                break;
        default:
                return 0;
        }
        error = sock->ops->getname(sock, addr, &addr_len, 2);
        if (error)
                return error;
        switch (addr->sa_family) {
                struct sockaddr_in6 *addr6;
                struct sockaddr_in *addr4;
        case AF_INET6:
                addr6 = (struct sockaddr_in6 *) addr;
                error = ccs_check_network_accept_acl(true,
                                                     addr6->sin6_addr.s6_addr,
                                                     addr6->sin6_port);
                break;
        case AF_INET:
                addr4 = (struct sockaddr_in *) addr;
                error = ccs_check_network_accept_acl(false,
                                                     (u8 *) &addr4->sin_addr,
                                                     addr4->sin_port);
                break;
        }
        return error;
}

/* Check permission for sending a datagram via a UDP or RAW socket. */
int ccs_socket_sendmsg_permission(struct socket *sock, struct sockaddr *addr,
                                  int addr_len)
{
        int error = 0;
        const int type = sock->type;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;
        if (!addr || (type != SOCK_DGRAM && type != SOCK_RAW))
                return 0;
        switch (addr->sa_family) {
                struct sockaddr_in6 *addr6;
                struct sockaddr_in *addr4;
                u16 port;
        case AF_INET6:
                if (addr_len < SIN6_LEN_RFC2133)
                        break;
                addr6 = (struct sockaddr_in6 *) addr;
                if (type == SOCK_DGRAM)
                        port = addr6->sin6_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_sendmsg_acl(true, type,
                                                      addr6->sin6_addr.s6_addr,
                                                      port);
                break;
        case AF_INET:
                if (addr_len < sizeof(struct sockaddr_in))
                        break;
                addr4 = (struct sockaddr_in *) addr;
                if (type == SOCK_DGRAM)
                        port = addr4->sin_port;
                else
                        port = htons(sock->sk->sk_protocol);
                error = ccs_check_network_sendmsg_acl(false, type,
                                                      (u8 *) &addr4->sin_addr,
                                                      port);
                break;
        }
        return error;
}

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 22)
#if !defined(RHEL_MAJOR) || RHEL_MAJOR != 5

static inline struct iphdr *ip_hdr(const struct sk_buff *skb)
{
        return skb->nh.iph;
}

static inline struct udphdr *udp_hdr(const struct sk_buff *skb)
{
        return skb->h.uh;
}

static inline struct ipv6hdr *ipv6_hdr(const struct sk_buff *skb)
{
        return skb->nh.ipv6h;
}

#endif
#endif

#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 12)
static void skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
                              unsigned int flags)
{
        /* Clear queue. */
        if (flags & MSG_PEEK) {
                int clear = 0;
                spin_lock_irq(&sk->sk_receive_queue.lock);
                if (skb == skb_peek(&sk->sk_receive_queue)) {
                        __skb_unlink(skb, &sk->sk_receive_queue);
                        clear = 1;
                }
                spin_unlock_irq(&sk->sk_receive_queue.lock);
                if (clear)
                        kfree_skb(skb);
        }
}
#elif LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 16)
static void skb_kill_datagram(struct sock *sk, struct sk_buff *skb,
                              unsigned int flags)
{
        /* Clear queue. */
        if (flags & MSG_PEEK) {
                int clear = 0;
                spin_lock_bh(&sk->sk_receive_queue.lock);
                if (skb == skb_peek(&sk->sk_receive_queue)) {
                        __skb_unlink(skb, &sk->sk_receive_queue);
                        clear = 1;
                }
                spin_unlock_bh(&sk->sk_receive_queue.lock);
                if (clear)
                        kfree_skb(skb);
        }
}
#endif

/*
 * Check permission for receiving a datagram via a UDP or RAW socket.
 *
 * Currently, the LSM hook for this purpose is not provided.
 */
int ccs_socket_recvmsg_permission(struct sock *sk, struct sk_buff *skb,
                                  const unsigned int flags)
{
        int error = 0;
        const unsigned int type = sk->sk_type;
        if (type != SOCK_DGRAM && type != SOCK_RAW)
                return 0;
        /* Nothing to do if I am a kernel service. */
        if (segment_eq(get_fs(), KERNEL_DS))
                return 0;

        switch (sk->sk_family) {
                struct in6_addr sin6;
                struct in_addr sin4;
                u16 port;
        case PF_INET6:
                if (type == SOCK_DGRAM) { /* UDP IPv6 */
                        if (skb->protocol == htons(ETH_P_IP)) {
                                ipv6_addr_set(&sin6, 0, 0, htonl(0xffff),
                                              ip_hdr(skb)->saddr);
                        } else {
                                ipv6_addr_copy(&sin6, &ipv6_hdr(skb)->saddr);
                        }
                        port = udp_hdr(skb)->source;
                } else { /* RAW IPv6 */
                        ipv6_addr_copy(&sin6, &ipv6_hdr(skb)->saddr);
                        port = htons(sk->sk_protocol);
                }
                error = ccs_check_network_recvmsg_acl(true, type,
                                                      (u8 *) &sin6, port);
                break;
        case PF_INET:
                if (type == SOCK_DGRAM) { /* UDP IPv4 */
                        sin4.s_addr = ip_hdr(skb)->saddr;
                        port = udp_hdr(skb)->source;
                } else { /* RAW IPv4 */
                        sin4.s_addr = ip_hdr(skb)->saddr;
                        port = htons(sk->sk_protocol);
                }
                error = ccs_check_network_recvmsg_acl(false, type,
                                                      (u8 *) &sin4, port);
                break;
        }
        if (!error)
                return 0;
        /*
         * Remove from queue if MSG_PEEK is used so that
         * the head message from unwanted source in receive queue will not
         * prevent the caller from picking up next message from wanted source
         * when the caller is using MSG_PEEK flag for picking up.
         */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 25)
        if (type == SOCK_DGRAM)
                lock_sock(sk);
#endif
        skb_kill_datagram(sk, skb, flags);
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 25)
        if (type == SOCK_DGRAM)
                release_sock(sk);
#endif
        /* Hope less harmful than -EPERM. */
        return -EAGAIN;
}
EXPORT_SYMBOL(ccs_socket_recvmsg_permission);