netlabel: Move bitmap manipulation functions to the NetLabel core.

[deliverable/linux.git] / net / netlabel / netlabel_kapi.c

/*
 * NetLabel Kernel API
 *
 * This file defines the kernel API for the NetLabel system.  The NetLabel
 * system manages static and dynamic label mappings for network protocols such
 * as CIPSO and RIPSO.
 *
 * Author: Paul Moore <paul@paul-moore.com>
 *
 */

/*
 * (c) Copyright Hewlett-Packard Development Company, L.P., 2006, 2008
 *
 * This program is free software;  you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY;  without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program;  if not, see <http://www.gnu.org/licenses/>.
 *
 */

#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/audit.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/netlabel.h>
#include <net/cipso_ipv4.h>
#include <asm/bug.h>
#include <linux/atomic.h>

#include "netlabel_domainhash.h"
#include "netlabel_unlabeled.h"
#include "netlabel_cipso_v4.h"
#include "netlabel_user.h"
#include "netlabel_mgmt.h"
#include "netlabel_addrlist.h"

/*
 * Configuration Functions
 */

/**
 * netlbl_cfg_map_del - Remove a NetLabel/LSM domain mapping
 * @domain: the domain mapping to remove
 * @family: address family
 * @addr: IP address
 * @mask: IP address mask
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Removes a NetLabel/LSM domain mapping.  A @domain value of NULL causes the
 * default domain mapping to be removed.  Returns zero on success, negative
 * values on failure.
 *
 */
int netlbl_cfg_map_del(const char *domain,
                       u16 family,
                       const void *addr,
                       const void *mask,
                       struct netlbl_audit *audit_info)
{
        if (addr == NULL && mask == NULL) {
                return netlbl_domhsh_remove(domain, family, audit_info);
        } else if (addr != NULL && mask != NULL) {
                switch (family) {
                case AF_INET:
                        return netlbl_domhsh_remove_af4(domain, addr, mask,
                                                        audit_info);
                default:
                        return -EPFNOSUPPORT;
                }
        } else
                return -EINVAL;
}

/**
 * netlbl_cfg_unlbl_map_add - Add a new unlabeled mapping
 * @domain: the domain mapping to add
 * @family: address family
 * @addr: IP address
 * @mask: IP address mask
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Adds a new unlabeled NetLabel/LSM domain mapping.  A @domain value of NULL
 * causes a new default domain mapping to be added.  Returns zero on success,
 * negative values on failure.
 *
 */
int netlbl_cfg_unlbl_map_add(const char *domain,
                             u16 family,
                             const void *addr,
                             const void *mask,
                             struct netlbl_audit *audit_info)
{
        int ret_val = -ENOMEM;
        struct netlbl_dom_map *entry;
        struct netlbl_domaddr_map *addrmap = NULL;
        struct netlbl_domaddr4_map *map4 = NULL;
        struct netlbl_domaddr6_map *map6 = NULL;

        entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
        if (entry == NULL)
                return -ENOMEM;
        if (domain != NULL) {
                entry->domain = kstrdup(domain, GFP_ATOMIC);
                if (entry->domain == NULL)
                        goto cfg_unlbl_map_add_failure;
        }
        entry->family = family;

        if (addr == NULL && mask == NULL)
                entry->def.type = NETLBL_NLTYPE_UNLABELED;
        else if (addr != NULL && mask != NULL) {
                addrmap = kzalloc(sizeof(*addrmap), GFP_ATOMIC);
                if (addrmap == NULL)
                        goto cfg_unlbl_map_add_failure;
                INIT_LIST_HEAD(&addrmap->list4);
                INIT_LIST_HEAD(&addrmap->list6);

                switch (family) {
                case AF_INET: {
                        const struct in_addr *addr4 = addr;
                        const struct in_addr *mask4 = mask;
                        map4 = kzalloc(sizeof(*map4), GFP_ATOMIC);
                        if (map4 == NULL)
                                goto cfg_unlbl_map_add_failure;
                        map4->def.type = NETLBL_NLTYPE_UNLABELED;
                        map4->list.addr = addr4->s_addr & mask4->s_addr;
                        map4->list.mask = mask4->s_addr;
                        map4->list.valid = 1;
                        ret_val = netlbl_af4list_add(&map4->list,
                                                     &addrmap->list4);
                        if (ret_val != 0)
                                goto cfg_unlbl_map_add_failure;
                        break;
                        }
#if IS_ENABLED(CONFIG_IPV6)
                case AF_INET6: {
                        const struct in6_addr *addr6 = addr;
                        const struct in6_addr *mask6 = mask;
                        map6 = kzalloc(sizeof(*map6), GFP_ATOMIC);
                        if (map6 == NULL)
                                goto cfg_unlbl_map_add_failure;
                        map6->def.type = NETLBL_NLTYPE_UNLABELED;
                        map6->list.addr = *addr6;
                        map6->list.addr.s6_addr32[0] &= mask6->s6_addr32[0];
                        map6->list.addr.s6_addr32[1] &= mask6->s6_addr32[1];
                        map6->list.addr.s6_addr32[2] &= mask6->s6_addr32[2];
                        map6->list.addr.s6_addr32[3] &= mask6->s6_addr32[3];
                        map6->list.mask = *mask6;
                        map6->list.valid = 1;
                        ret_val = netlbl_af6list_add(&map6->list,
                                                     &addrmap->list6);
                        if (ret_val != 0)
                                goto cfg_unlbl_map_add_failure;
                        break;
                        }
#endif /* IPv6 */
                default:
                        goto cfg_unlbl_map_add_failure;
                }

                entry->def.addrsel = addrmap;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
        } else {
                ret_val = -EINVAL;
                goto cfg_unlbl_map_add_failure;
        }

        ret_val = netlbl_domhsh_add(entry, audit_info);
        if (ret_val != 0)
                goto cfg_unlbl_map_add_failure;

        return 0;

cfg_unlbl_map_add_failure:
        kfree(entry->domain);
        kfree(entry);
        kfree(addrmap);
        kfree(map4);
        kfree(map6);
        return ret_val;
}


/**
 * netlbl_cfg_unlbl_static_add - Adds a new static label
 * @net: network namespace
 * @dev_name: interface name
 * @addr: IP address in network byte order (struct in[6]_addr)
 * @mask: address mask in network byte order (struct in[6]_addr)
 * @family: address family
 * @secid: LSM secid value for the entry
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Adds a new NetLabel static label to be used when protocol provided labels
 * are not present on incoming traffic.  If @dev_name is NULL then the default
 * interface will be used.  Returns zero on success, negative values on failure.
 *
 */
int netlbl_cfg_unlbl_static_add(struct net *net,
                                const char *dev_name,
                                const void *addr,
                                const void *mask,
                                u16 family,
                                u32 secid,
                                struct netlbl_audit *audit_info)
{
        u32 addr_len;

        switch (family) {
        case AF_INET:
                addr_len = sizeof(struct in_addr);
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                addr_len = sizeof(struct in6_addr);
                break;
#endif /* IPv6 */
        default:
                return -EPFNOSUPPORT;
        }

        return netlbl_unlhsh_add(net,
                                 dev_name, addr, mask, addr_len,
                                 secid, audit_info);
}

/**
 * netlbl_cfg_unlbl_static_del - Removes an existing static label
 * @net: network namespace
 * @dev_name: interface name
 * @addr: IP address in network byte order (struct in[6]_addr)
 * @mask: address mask in network byte order (struct in[6]_addr)
 * @family: address family
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Removes an existing NetLabel static label used when protocol provided labels
 * are not present on incoming traffic.  If @dev_name is NULL then the default
 * interface will be used.  Returns zero on success, negative values on failure.
 *
 */
int netlbl_cfg_unlbl_static_del(struct net *net,
                                const char *dev_name,
                                const void *addr,
                                const void *mask,
                                u16 family,
                                struct netlbl_audit *audit_info)
{
        u32 addr_len;

        switch (family) {
        case AF_INET:
                addr_len = sizeof(struct in_addr);
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                addr_len = sizeof(struct in6_addr);
                break;
#endif /* IPv6 */
        default:
                return -EPFNOSUPPORT;
        }

        return netlbl_unlhsh_remove(net,
                                    dev_name, addr, mask, addr_len,
                                    audit_info);
}

/**
 * netlbl_cfg_cipsov4_add - Add a new CIPSOv4 DOI definition
 * @doi_def: CIPSO DOI definition
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Add a new CIPSO DOI definition as defined by @doi_def.  Returns zero on
 * success and negative values on failure.
 *
 */
int netlbl_cfg_cipsov4_add(struct cipso_v4_doi *doi_def,
                           struct netlbl_audit *audit_info)
{
        return cipso_v4_doi_add(doi_def, audit_info);
}

/**
 * netlbl_cfg_cipsov4_del - Remove an existing CIPSOv4 DOI definition
 * @doi: CIPSO DOI
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Remove an existing CIPSO DOI definition matching @doi.  Returns zero on
 * success and negative values on failure.
 *
 */
void netlbl_cfg_cipsov4_del(u32 doi, struct netlbl_audit *audit_info)
{
        cipso_v4_doi_remove(doi, audit_info);
}

/**
 * netlbl_cfg_cipsov4_map_add - Add a new CIPSOv4 DOI mapping
 * @doi: the CIPSO DOI
 * @domain: the domain mapping to add
 * @addr: IP address
 * @mask: IP address mask
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Add a new NetLabel/LSM domain mapping for the given CIPSO DOI to the NetLabel
 * subsystem.  A @domain value of NULL adds a new default domain mapping.
 * Returns zero on success, negative values on failure.
 *
 */
int netlbl_cfg_cipsov4_map_add(u32 doi,
                               const char *domain,
                               const struct in_addr *addr,
                               const struct in_addr *mask,
                               struct netlbl_audit *audit_info)
{
        int ret_val = -ENOMEM;
        struct cipso_v4_doi *doi_def;
        struct netlbl_dom_map *entry;
        struct netlbl_domaddr_map *addrmap = NULL;
        struct netlbl_domaddr4_map *addrinfo = NULL;

        doi_def = cipso_v4_doi_getdef(doi);
        if (doi_def == NULL)
                return -ENOENT;

        entry = kzalloc(sizeof(*entry), GFP_ATOMIC);
        if (entry == NULL)
                goto out_entry;
        entry->family = AF_INET;
        if (domain != NULL) {
                entry->domain = kstrdup(domain, GFP_ATOMIC);
                if (entry->domain == NULL)
                        goto out_domain;
        }

        if (addr == NULL && mask == NULL) {
                entry->def.cipso = doi_def;
                entry->def.type = NETLBL_NLTYPE_CIPSOV4;
        } else if (addr != NULL && mask != NULL) {
                addrmap = kzalloc(sizeof(*addrmap), GFP_ATOMIC);
                if (addrmap == NULL)
                        goto out_addrmap;
                INIT_LIST_HEAD(&addrmap->list4);
                INIT_LIST_HEAD(&addrmap->list6);

                addrinfo = kzalloc(sizeof(*addrinfo), GFP_ATOMIC);
                if (addrinfo == NULL)
                        goto out_addrinfo;
                addrinfo->def.cipso = doi_def;
                addrinfo->def.type = NETLBL_NLTYPE_CIPSOV4;
                addrinfo->list.addr = addr->s_addr & mask->s_addr;
                addrinfo->list.mask = mask->s_addr;
                addrinfo->list.valid = 1;
                ret_val = netlbl_af4list_add(&addrinfo->list, &addrmap->list4);
                if (ret_val != 0)
                        goto cfg_cipsov4_map_add_failure;

                entry->def.addrsel = addrmap;
                entry->def.type = NETLBL_NLTYPE_ADDRSELECT;
        } else {
                ret_val = -EINVAL;
                goto out_addrmap;
        }

        ret_val = netlbl_domhsh_add(entry, audit_info);
        if (ret_val != 0)
                goto cfg_cipsov4_map_add_failure;

        return 0;

cfg_cipsov4_map_add_failure:
        kfree(addrinfo);
out_addrinfo:
        kfree(addrmap);
out_addrmap:
        kfree(entry->domain);
out_domain:
        kfree(entry);
out_entry:
        cipso_v4_doi_putdef(doi_def);
        return ret_val;
}

/*
 * Security Attribute Functions
 */

#define _CM_F_NONE      0x00000000
#define _CM_F_ALLOC     0x00000001
#define _CM_F_WALK      0x00000002

/**
 * _netlbl_catmap_getnode - Get a individual node from a catmap
 * @catmap: pointer to the category bitmap
 * @offset: the requested offset
 * @cm_flags: catmap flags, see _CM_F_*
 * @gfp_flags: memory allocation flags
 *
 * Description:
 * Iterate through the catmap looking for the node associated with @offset.
 * If the _CM_F_ALLOC flag is set in @cm_flags and there is no associated node,
 * one will be created and inserted into the catmap.  If the _CM_F_WALK flag is
 * set in @cm_flags and there is no associated node, the next highest node will
 * be returned.  Returns a pointer to the node on success, NULL on failure.
 *
 */
static struct netlbl_lsm_catmap *_netlbl_catmap_getnode(
                                             struct netlbl_lsm_catmap **catmap,
                                             u32 offset,
                                             unsigned int cm_flags,
                                             gfp_t gfp_flags)
{
        struct netlbl_lsm_catmap *iter = *catmap;
        struct netlbl_lsm_catmap *prev = NULL;

        if (iter == NULL)
                goto catmap_getnode_alloc;
        if (offset < iter->startbit)
                goto catmap_getnode_walk;
        while (iter && offset >= (iter->startbit + NETLBL_CATMAP_SIZE)) {
                prev = iter;
                iter = iter->next;
        }
        if (iter == NULL || offset < iter->startbit)
                goto catmap_getnode_walk;

        return iter;

catmap_getnode_walk:
        if (cm_flags & _CM_F_WALK)
                return iter;
catmap_getnode_alloc:
        if (!(cm_flags & _CM_F_ALLOC))
                return NULL;

        iter = netlbl_catmap_alloc(gfp_flags);
        if (iter == NULL)
                return NULL;
        iter->startbit = offset & ~(NETLBL_CATMAP_SIZE - 1);

        if (prev == NULL) {
                iter->next = *catmap;
                *catmap = iter;
        } else {
                iter->next = prev->next;
                prev->next = iter;
        }

        return iter;
}

/**
 * netlbl_catmap_walk - Walk a LSM secattr catmap looking for a bit
 * @catmap: the category bitmap
 * @offset: the offset to start searching at, in bits
 *
 * Description:
 * This function walks a LSM secattr category bitmap starting at @offset and
 * returns the spot of the first set bit or -ENOENT if no bits are set.
 *
 */
int netlbl_catmap_walk(struct netlbl_lsm_catmap *catmap, u32 offset)
{
        struct netlbl_lsm_catmap *iter = catmap;
        u32 idx;
        u32 bit;
        NETLBL_CATMAP_MAPTYPE bitmap;

        iter = _netlbl_catmap_getnode(&catmap, offset, _CM_F_WALK, 0);
        if (iter == NULL)
                return -ENOENT;
        if (offset > iter->startbit) {
                offset -= iter->startbit;
                idx = offset / NETLBL_CATMAP_MAPSIZE;
                bit = offset % NETLBL_CATMAP_MAPSIZE;
        } else {
                idx = 0;
                bit = 0;
        }
        bitmap = iter->bitmap[idx] >> bit;

        for (;;) {
                if (bitmap != 0) {
                        while ((bitmap & NETLBL_CATMAP_BIT) == 0) {
                                bitmap >>= 1;
                                bit++;
                        }
                        return iter->startbit +
                               (NETLBL_CATMAP_MAPSIZE * idx) + bit;
                }
                if (++idx >= NETLBL_CATMAP_MAPCNT) {
                        if (iter->next != NULL) {
                                iter = iter->next;
                                idx = 0;
                        } else
                                return -ENOENT;
                }
                bitmap = iter->bitmap[idx];
                bit = 0;
        }

        return -ENOENT;
}

/**
 * netlbl_catmap_walkrng - Find the end of a string of set bits
 * @catmap: the category bitmap
 * @offset: the offset to start searching at, in bits
 *
 * Description:
 * This function walks a LSM secattr category bitmap starting at @offset and
 * returns the spot of the first cleared bit or -ENOENT if the offset is past
 * the end of the bitmap.
 *
 */
int netlbl_catmap_walkrng(struct netlbl_lsm_catmap *catmap, u32 offset)
{
        struct netlbl_lsm_catmap *iter;
        struct netlbl_lsm_catmap *prev = NULL;
        u32 idx;
        u32 bit;
        NETLBL_CATMAP_MAPTYPE bitmask;
        NETLBL_CATMAP_MAPTYPE bitmap;

        iter = _netlbl_catmap_getnode(&catmap, offset, _CM_F_WALK, 0);
        if (iter == NULL)
                return -ENOENT;
        if (offset > iter->startbit) {
                offset -= iter->startbit;
                idx = offset / NETLBL_CATMAP_MAPSIZE;
                bit = offset % NETLBL_CATMAP_MAPSIZE;
        } else {
                idx = 0;
                bit = 0;
        }
        bitmask = NETLBL_CATMAP_BIT << bit;

        for (;;) {
                bitmap = iter->bitmap[idx];
                while (bitmask != 0 && (bitmap & bitmask) != 0) {
                        bitmask <<= 1;
                        bit++;
                }

                if (prev && idx == 0 && bit == 0)
                        return prev->startbit + NETLBL_CATMAP_SIZE - 1;
                else if (bitmask != 0)
                        return iter->startbit +
                                (NETLBL_CATMAP_MAPSIZE * idx) + bit - 1;
                else if (++idx >= NETLBL_CATMAP_MAPCNT) {
                        if (iter->next == NULL)
                                return iter->startbit + NETLBL_CATMAP_SIZE - 1;
                        prev = iter;
                        iter = iter->next;
                        idx = 0;
                }
                bitmask = NETLBL_CATMAP_BIT;
                bit = 0;
        }

        return -ENOENT;
}

/**
 * netlbl_catmap_getlong - Export an unsigned long bitmap
 * @catmap: pointer to the category bitmap
 * @offset: pointer to the requested offset
 * @bitmap: the exported bitmap
 *
 * Description:
 * Export a bitmap with an offset greater than or equal to @offset and return
 * it in @bitmap.  The @offset must be aligned to an unsigned long and will be
 * updated on return if different from what was requested; if the catmap is
 * empty at the requested offset and beyond, the @offset is set to (u32)-1.
 * Returns zero on sucess, negative values on failure.
 *
 */
int netlbl_catmap_getlong(struct netlbl_lsm_catmap *catmap,
                          u32 *offset,
                          unsigned long *bitmap)
{
        struct netlbl_lsm_catmap *iter;
        u32 off = *offset;
        u32 idx;

        /* only allow aligned offsets */
        if ((off & (BITS_PER_LONG - 1)) != 0)
                return -EINVAL;

        if (off < catmap->startbit) {
                off = catmap->startbit;
                *offset = off;
        }
        iter = _netlbl_catmap_getnode(&catmap, off, _CM_F_WALK, 0);
        if (iter == NULL) {
                *offset = (u32)-1;
                return 0;
        }

        if (off < iter->startbit) {
                *offset = iter->startbit;
                off = 0;
        } else
                off -= iter->startbit;
        idx = off / NETLBL_CATMAP_MAPSIZE;
        *bitmap = iter->bitmap[idx] >> (off % NETLBL_CATMAP_MAPSIZE);

        return 0;
}

/**
 * netlbl_catmap_setbit - Set a bit in a LSM secattr catmap
 * @catmap: pointer to the category bitmap
 * @bit: the bit to set
 * @flags: memory allocation flags
 *
 * Description:
 * Set the bit specified by @bit in @catmap.  Returns zero on success,
 * negative values on failure.
 *
 */
int netlbl_catmap_setbit(struct netlbl_lsm_catmap **catmap,
                         u32 bit,
                         gfp_t flags)
{
        struct netlbl_lsm_catmap *iter;
        u32 idx;

        iter = _netlbl_catmap_getnode(catmap, bit, _CM_F_ALLOC, flags);
        if (iter == NULL)
                return -ENOMEM;

        bit -= iter->startbit;
        idx = bit / NETLBL_CATMAP_MAPSIZE;
        iter->bitmap[idx] |= NETLBL_CATMAP_BIT << (bit % NETLBL_CATMAP_MAPSIZE);

        return 0;
}

/**
 * netlbl_catmap_setrng - Set a range of bits in a LSM secattr catmap
 * @catmap: pointer to the category bitmap
 * @start: the starting bit
 * @end: the last bit in the string
 * @flags: memory allocation flags
 *
 * Description:
 * Set a range of bits, starting at @start and ending with @end.  Returns zero
 * on success, negative values on failure.
 *
 */
int netlbl_catmap_setrng(struct netlbl_lsm_catmap **catmap,
                         u32 start,
                         u32 end,
                         gfp_t flags)
{
        int rc = 0;
        u32 spot = start;

        while (rc == 0 && spot <= end) {
                if (((spot & (BITS_PER_LONG - 1)) == 0) &&
                    ((end - spot) > BITS_PER_LONG)) {
                        rc = netlbl_catmap_setlong(catmap,
                                                   spot,
                                                   (unsigned long)-1,
                                                   flags);
                        spot += BITS_PER_LONG;
                } else
                        rc = netlbl_catmap_setbit(catmap, spot++, flags);
        }

        return rc;
}

/**
 * netlbl_catmap_setlong - Import an unsigned long bitmap
 * @catmap: pointer to the category bitmap
 * @offset: offset to the start of the imported bitmap
 * @bitmap: the bitmap to import
 * @flags: memory allocation flags
 *
 * Description:
 * Import the bitmap specified in @bitmap into @catmap, using the offset
 * in @offset.  The offset must be aligned to an unsigned long.  Returns zero
 * on success, negative values on failure.
 *
 */
int netlbl_catmap_setlong(struct netlbl_lsm_catmap **catmap,
                          u32 offset,
                          unsigned long bitmap,
                          gfp_t flags)
{
        struct netlbl_lsm_catmap *iter;
        u32 idx;

        /* only allow aligned offsets */
        if ((offset & (BITS_PER_LONG - 1)) != 0)
                return -EINVAL;

        iter = _netlbl_catmap_getnode(catmap, offset, _CM_F_ALLOC, flags);
        if (iter == NULL)
                return -ENOMEM;

        offset -= iter->startbit;
        idx = offset / NETLBL_CATMAP_MAPSIZE;
        iter->bitmap[idx] |= bitmap << (offset % NETLBL_CATMAP_MAPSIZE);

        return 0;
}

/* Bitmap functions
 */

/**
 * netlbl_bitmap_walk - Walk a bitmap looking for a bit
 * @bitmap: the bitmap
 * @bitmap_len: length in bits
 * @offset: starting offset
 * @state: if non-zero, look for a set (1) bit else look for a cleared (0) bit
 *
 * Description:
 * Starting at @offset, walk the bitmap from left to right until either the
 * desired bit is found or we reach the end.  Return the bit offset, -1 if
 * not found, or -2 if error.
 */
int netlbl_bitmap_walk(const unsigned char *bitmap, u32 bitmap_len,
                       u32 offset, u8 state)
{
        u32 bit_spot;
        u32 byte_offset;
        unsigned char bitmask;
        unsigned char byte;

        byte_offset = offset / 8;
        byte = bitmap[byte_offset];
        bit_spot = offset;
        bitmask = 0x80 >> (offset % 8);

        while (bit_spot < bitmap_len) {
                if ((state && (byte & bitmask) == bitmask) ||
                    (state == 0 && (byte & bitmask) == 0))
                        return bit_spot;

                bit_spot++;
                bitmask >>= 1;
                if (bitmask == 0) {
                        byte = bitmap[++byte_offset];
                        bitmask = 0x80;
                }
        }

        return -1;
}
EXPORT_SYMBOL(netlbl_bitmap_walk);

/**
 * netlbl_bitmap_setbit - Sets a single bit in a bitmap
 * @bitmap: the bitmap
 * @bit: the bit
 * @state: if non-zero, set the bit (1) else clear the bit (0)
 *
 * Description:
 * Set a single bit in the bitmask.  Returns zero on success, negative values
 * on error.
 */
void netlbl_bitmap_setbit(unsigned char *bitmap, u32 bit, u8 state)
{
        u32 byte_spot;
        u8 bitmask;

        /* gcc always rounds to zero when doing integer division */
        byte_spot = bit / 8;
        bitmask = 0x80 >> (bit % 8);
        if (state)
                bitmap[byte_spot] |= bitmask;
        else
                bitmap[byte_spot] &= ~bitmask;
}
EXPORT_SYMBOL(netlbl_bitmap_setbit);

/*
 * LSM Functions
 */

/**
 * netlbl_enabled - Determine if the NetLabel subsystem is enabled
 *
 * Description:
 * The LSM can use this function to determine if it should use NetLabel
 * security attributes in it's enforcement mechanism.  Currently, NetLabel is
 * considered to be enabled when it's configuration contains a valid setup for
 * at least one labeled protocol (i.e. NetLabel can understand incoming
 * labeled packets of at least one type); otherwise NetLabel is considered to
 * be disabled.
 *
 */
int netlbl_enabled(void)
{
        /* At some point we probably want to expose this mechanism to the user
         * as well so that admins can toggle NetLabel regardless of the
         * configuration */
        return (atomic_read(&netlabel_mgmt_protocount) > 0);
}

/**
 * netlbl_sock_setattr - Label a socket using the correct protocol
 * @sk: the socket to label
 * @family: protocol family
 * @secattr: the security attributes
 *
 * Description:
 * Attach the correct label to the given socket using the security attributes
 * specified in @secattr.  This function requires exclusive access to @sk,
 * which means it either needs to be in the process of being created or locked.
 * Returns zero on success, -EDESTADDRREQ if the domain is configured to use
 * network address selectors (can't blindly label the socket), and negative
 * values on all other failures.
 *
 */
int netlbl_sock_setattr(struct sock *sk,
                        u16 family,
                        const struct netlbl_lsm_secattr *secattr)
{
        int ret_val;
        struct netlbl_dom_map *dom_entry;

        rcu_read_lock();
        dom_entry = netlbl_domhsh_getentry(secattr->domain, family);
        if (dom_entry == NULL) {
                ret_val = -ENOENT;
                goto socket_setattr_return;
        }
        switch (family) {
        case AF_INET:
                switch (dom_entry->def.type) {
                case NETLBL_NLTYPE_ADDRSELECT:
                        ret_val = -EDESTADDRREQ;
                        break;
                case NETLBL_NLTYPE_CIPSOV4:
                        ret_val = cipso_v4_sock_setattr(sk,
                                                        dom_entry->def.cipso,
                                                        secattr);
                        break;
                case NETLBL_NLTYPE_UNLABELED:
                        ret_val = 0;
                        break;
                default:
                        ret_val = -ENOENT;
                }
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                /* since we don't support any IPv6 labeling protocols right
                 * now we can optimize everything away until we do */
                ret_val = 0;
                break;
#endif /* IPv6 */
        default:
                ret_val = -EPROTONOSUPPORT;
        }

socket_setattr_return:
        rcu_read_unlock();
        return ret_val;
}

/**
 * netlbl_sock_delattr - Delete all the NetLabel labels on a socket
 * @sk: the socket
 *
 * Description:
 * Remove all the NetLabel labeling from @sk.  The caller is responsible for
 * ensuring that @sk is locked.
 *
 */
void netlbl_sock_delattr(struct sock *sk)
{
        switch (sk->sk_family) {
        case AF_INET:
                cipso_v4_sock_delattr(sk);
                break;
        }
}

/**
 * netlbl_sock_getattr - Determine the security attributes of a sock
 * @sk: the sock
 * @secattr: the security attributes
 *
 * Description:
 * Examines the given sock to see if any NetLabel style labeling has been
 * applied to the sock, if so it parses the socket label and returns the
 * security attributes in @secattr.  Returns zero on success, negative values
 * on failure.
 *
 */
int netlbl_sock_getattr(struct sock *sk,
                        struct netlbl_lsm_secattr *secattr)
{
        int ret_val;

        switch (sk->sk_family) {
        case AF_INET:
                ret_val = cipso_v4_sock_getattr(sk, secattr);
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                ret_val = -ENOMSG;
                break;
#endif /* IPv6 */
        default:
                ret_val = -EPROTONOSUPPORT;
        }

        return ret_val;
}

/**
 * netlbl_conn_setattr - Label a connected socket using the correct protocol
 * @sk: the socket to label
 * @addr: the destination address
 * @secattr: the security attributes
 *
 * Description:
 * Attach the correct label to the given connected socket using the security
 * attributes specified in @secattr.  The caller is responsible for ensuring
 * that @sk is locked.  Returns zero on success, negative values on failure.
 *
 */
int netlbl_conn_setattr(struct sock *sk,
                        struct sockaddr *addr,
                        const struct netlbl_lsm_secattr *secattr)
{
        int ret_val;
        struct sockaddr_in *addr4;
        struct netlbl_dommap_def *entry;

        rcu_read_lock();
        switch (addr->sa_family) {
        case AF_INET:
                addr4 = (struct sockaddr_in *)addr;
                entry = netlbl_domhsh_getentry_af4(secattr->domain,
                                                   addr4->sin_addr.s_addr);
                if (entry == NULL) {
                        ret_val = -ENOENT;
                        goto conn_setattr_return;
                }
                switch (entry->type) {
                case NETLBL_NLTYPE_CIPSOV4:
                        ret_val = cipso_v4_sock_setattr(sk,
                                                        entry->cipso, secattr);
                        break;
                case NETLBL_NLTYPE_UNLABELED:
                        /* just delete the protocols we support for right now
                         * but we could remove other protocols if needed */
                        cipso_v4_sock_delattr(sk);
                        ret_val = 0;
                        break;
                default:
                        ret_val = -ENOENT;
                }
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                /* since we don't support any IPv6 labeling protocols right
                 * now we can optimize everything away until we do */
                ret_val = 0;
                break;
#endif /* IPv6 */
        default:
                ret_val = -EPROTONOSUPPORT;
        }

conn_setattr_return:
        rcu_read_unlock();
        return ret_val;
}

/**
 * netlbl_req_setattr - Label a request socket using the correct protocol
 * @req: the request socket to label
 * @secattr: the security attributes
 *
 * Description:
 * Attach the correct label to the given socket using the security attributes
 * specified in @secattr.  Returns zero on success, negative values on failure.
 *
 */
int netlbl_req_setattr(struct request_sock *req,
                       const struct netlbl_lsm_secattr *secattr)
{
        int ret_val;
        struct netlbl_dommap_def *entry;

        rcu_read_lock();
        switch (req->rsk_ops->family) {
        case AF_INET:
                entry = netlbl_domhsh_getentry_af4(secattr->domain,
                                                   inet_rsk(req)->ir_rmt_addr);
                if (entry == NULL) {
                        ret_val = -ENOENT;
                        goto req_setattr_return;
                }
                switch (entry->type) {
                case NETLBL_NLTYPE_CIPSOV4:
                        ret_val = cipso_v4_req_setattr(req,
                                                       entry->cipso, secattr);
                        break;
                case NETLBL_NLTYPE_UNLABELED:
                        /* just delete the protocols we support for right now
                         * but we could remove other protocols if needed */
                        cipso_v4_req_delattr(req);
                        ret_val = 0;
                        break;
                default:
                        ret_val = -ENOENT;
                }
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                /* since we don't support any IPv6 labeling protocols right
                 * now we can optimize everything away until we do */
                ret_val = 0;
                break;
#endif /* IPv6 */
        default:
                ret_val = -EPROTONOSUPPORT;
        }

req_setattr_return:
        rcu_read_unlock();
        return ret_val;
}

/**
* netlbl_req_delattr - Delete all the NetLabel labels on a socket
* @req: the socket
*
* Description:
* Remove all the NetLabel labeling from @req.
*
*/
void netlbl_req_delattr(struct request_sock *req)
{
        switch (req->rsk_ops->family) {
        case AF_INET:
                cipso_v4_req_delattr(req);
                break;
        }
}

/**
 * netlbl_skbuff_setattr - Label a packet using the correct protocol
 * @skb: the packet
 * @family: protocol family
 * @secattr: the security attributes
 *
 * Description:
 * Attach the correct label to the given packet using the security attributes
 * specified in @secattr.  Returns zero on success, negative values on failure.
 *
 */
int netlbl_skbuff_setattr(struct sk_buff *skb,
                          u16 family,
                          const struct netlbl_lsm_secattr *secattr)
{
        int ret_val;
        struct iphdr *hdr4;
        struct netlbl_dommap_def *entry;

        rcu_read_lock();
        switch (family) {
        case AF_INET:
                hdr4 = ip_hdr(skb);
                entry = netlbl_domhsh_getentry_af4(secattr->domain,hdr4->daddr);
                if (entry == NULL) {
                        ret_val = -ENOENT;
                        goto skbuff_setattr_return;
                }
                switch (entry->type) {
                case NETLBL_NLTYPE_CIPSOV4:
                        ret_val = cipso_v4_skbuff_setattr(skb, entry->cipso,
                                                          secattr);
                        break;
                case NETLBL_NLTYPE_UNLABELED:
                        /* just delete the protocols we support for right now
                         * but we could remove other protocols if needed */
                        ret_val = cipso_v4_skbuff_delattr(skb);
                        break;
                default:
                        ret_val = -ENOENT;
                }
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                /* since we don't support any IPv6 labeling protocols right
                 * now we can optimize everything away until we do */
                ret_val = 0;
                break;
#endif /* IPv6 */
        default:
                ret_val = -EPROTONOSUPPORT;
        }

skbuff_setattr_return:
        rcu_read_unlock();
        return ret_val;
}

/**
 * netlbl_skbuff_getattr - Determine the security attributes of a packet
 * @skb: the packet
 * @family: protocol family
 * @secattr: the security attributes
 *
 * Description:
 * Examines the given packet to see if a recognized form of packet labeling
 * is present, if so it parses the packet label and returns the security
 * attributes in @secattr.  Returns zero on success, negative values on
 * failure.
 *
 */
int netlbl_skbuff_getattr(const struct sk_buff *skb,
                          u16 family,
                          struct netlbl_lsm_secattr *secattr)
{
        unsigned char *ptr;

        switch (family) {
        case AF_INET:
                ptr = cipso_v4_optptr(skb);
                if (ptr && cipso_v4_getattr(ptr, secattr) == 0)
                        return 0;
                break;
#if IS_ENABLED(CONFIG_IPV6)
        case AF_INET6:
                break;
#endif /* IPv6 */
        }

        return netlbl_unlabel_getattr(skb, family, secattr);
}

/**
 * netlbl_skbuff_err - Handle a LSM error on a sk_buff
 * @skb: the packet
 * @error: the error code
 * @gateway: true if host is acting as a gateway, false otherwise
 *
 * Description:
 * Deal with a LSM problem when handling the packet in @skb, typically this is
 * a permission denied problem (-EACCES).  The correct action is determined
 * according to the packet's labeling protocol.
 *
 */
void netlbl_skbuff_err(struct sk_buff *skb, int error, int gateway)
{
        if (cipso_v4_optptr(skb))
                cipso_v4_error(skb, error, gateway);
}

/**
 * netlbl_cache_invalidate - Invalidate all of the NetLabel protocol caches
 *
 * Description:
 * For all of the NetLabel protocols that support some form of label mapping
 * cache, invalidate the cache.  Returns zero on success, negative values on
 * error.
 *
 */
void netlbl_cache_invalidate(void)
{
        cipso_v4_cache_invalidate();
}

/**
 * netlbl_cache_add - Add an entry to a NetLabel protocol cache
 * @skb: the packet
 * @secattr: the packet's security attributes
 *
 * Description:
 * Add the LSM security attributes for the given packet to the underlying
 * NetLabel protocol's label mapping cache.  Returns zero on success, negative
 * values on error.
 *
 */
int netlbl_cache_add(const struct sk_buff *skb,
                     const struct netlbl_lsm_secattr *secattr)
{
        unsigned char *ptr;

        if ((secattr->flags & NETLBL_SECATTR_CACHE) == 0)
                return -ENOMSG;

        ptr = cipso_v4_optptr(skb);
        if (ptr)
                return cipso_v4_cache_add(ptr, secattr);

        return -ENOMSG;
}

/*
 * Protocol Engine Functions
 */

/**
 * netlbl_audit_start - Start an audit message
 * @type: audit message type
 * @audit_info: NetLabel audit information
 *
 * Description:
 * Start an audit message using the type specified in @type and fill the audit
 * message with some fields common to all NetLabel audit messages.  This
 * function should only be used by protocol engines, not LSMs.  Returns a
 * pointer to the audit buffer on success, NULL on failure.
 *
 */
struct audit_buffer *netlbl_audit_start(int type,
                                        struct netlbl_audit *audit_info)
{
        return netlbl_audit_start_common(type, audit_info);
}
EXPORT_SYMBOL(netlbl_audit_start);

/*
 * Setup Functions
 */

/**
 * netlbl_init - Initialize NetLabel
 *
 * Description:
 * Perform the required NetLabel initialization before first use.
 *
 */
static int __init netlbl_init(void)
{
        int ret_val;

        printk(KERN_INFO "NetLabel: Initializing\n");
        printk(KERN_INFO "NetLabel:  domain hash size = %u\n",
               (1 << NETLBL_DOMHSH_BITSIZE));
        printk(KERN_INFO "NetLabel:  protocols ="
               " UNLABELED"
               " CIPSOv4"
               "\n");

        ret_val = netlbl_domhsh_init(NETLBL_DOMHSH_BITSIZE);
        if (ret_val != 0)
                goto init_failure;

        ret_val = netlbl_unlabel_init(NETLBL_UNLHSH_BITSIZE);
        if (ret_val != 0)
                goto init_failure;

        ret_val = netlbl_netlink_init();
        if (ret_val != 0)
                goto init_failure;

        ret_val = netlbl_unlabel_defconf();
        if (ret_val != 0)
                goto init_failure;
        printk(KERN_INFO "NetLabel:  unlabeled traffic allowed by default\n");

        return 0;

init_failure:
        panic("NetLabel: failed to initialize properly (%d)\n", ret_val);
}

subsys_initcall(netlbl_init);