[apple/xnu.git] / bsd / netinet6 / ah_output.c

/*
 * Copyright (c) 2008-2019 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 *
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
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 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 *
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 *
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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/*      $FreeBSD: src/sys/netinet6/ah_output.c,v 1.1.2.3 2001/07/03 11:01:49 ume Exp $  */
/*      $KAME: ah_output.c,v 1.30 2001/02/21 00:50:53 itojun Exp $      */

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * RFC1826/2402 authentication header.
 */

#define _IP_VHL

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>

#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_var.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>

#include <netinet6/ipsec.h>
#include <netinet6/ipsec6.h>
#include <netinet6/ah.h>
#include <netinet6/ah6.h>
#include <netkey/key.h>
#include <netkey/keydb.h>

#include <net/net_osdep.h>

#if INET
static struct in_addr *ah4_finaldst(struct mbuf *);
#endif

extern lck_mtx_t *sadb_mutex;

/*
 * compute AH header size.
 * transport mode only.  for tunnel mode, we should implement
 * virtual interface, and control MTU/MSS by the interface MTU.
 */
size_t
ah_hdrsiz(struct ipsecrequest *isr)
{
        /* sanity check */
        if (isr == NULL) {
                panic("ah_hdrsiz: NULL was passed.\n");
        }

        if (isr->saidx.proto != IPPROTO_AH) {
                panic("unsupported mode passed to ah_hdrsiz");
        }

#if 0
        {
                lck_mtx_lock(sadb_mutex);
                const struct ah_algorithm *algo;
                size_t hdrsiz;

                /*%%%%% this needs to change - no sav in ipsecrequest any more */
                if (isr->sav == NULL) {
                        goto estimate;
                }
                if (isr->sav->state != SADB_SASTATE_MATURE
                    && isr->sav->state != SADB_SASTATE_DYING) {
                        goto estimate;
                }

                /* we need transport mode AH. */
                algo = ah_algorithm_lookup(isr->sav->alg_auth);
                if (!algo) {
                        goto estimate;
                }

                /*
                 * XXX
                 * right now we don't calcurate the padding size.  simply
                 * treat the padding size as constant, for simplicity.
                 *
                 * XXX variable size padding support
                 */
                hdrsiz = (((*algo->sumsiz)(isr->sav) + 3) & ~(4 - 1));
                if (isr->sav->flags & SADB_X_EXT_OLD) {
                        hdrsiz += sizeof(struct ah);
                } else {
                        hdrsiz += sizeof(struct newah);
                }

                lck_mtx_unlock(sadb_mutex);
                return hdrsiz;
        }

estimate:
#endif

        //lck_mtx_unlock(sadb_mutex);
        /* ASSUMING:
         *      sizeof(struct newah) > sizeof(struct ah).
         *      16 = (16 + 3) & ~(4 - 1).
         */
        return sizeof(struct newah) + 16;
}

#if INET
/*
 * Modify the packet so that it includes the authentication data.
 * The mbuf passed must start with IPv4 header.
 *
 * assumes that the first mbuf contains IPv4 header + option only.
 * the function does not modify m.
 */
int
ah4_output(struct mbuf *m, struct secasvar *sav)
{
        const struct ah_algorithm *algo;
        u_int32_t spi;
        u_char *ahdrpos;
        u_char *ahsumpos = NULL;
        size_t hlen = 0;        /*IP header+option in bytes*/
        size_t plen = 0;        /*AH payload size in bytes*/
        size_t ahlen = 0;       /*plen + sizeof(ah)*/
        struct ip *ip;
        struct in_addr dst = { .s_addr = 0 };
        struct in_addr *finaldst;
        int error;

        /* sanity checks */
        if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay[0] == NULL) {
                ip = mtod(m, struct ip *);
                ipseclog((LOG_DEBUG, "ah4_output: internal error: "
                    "sav->replay is null: %x->%x, SPI=%u\n",
                    (u_int32_t)ntohl(ip->ip_src.s_addr),
                    (u_int32_t)ntohl(ip->ip_dst.s_addr),
                    (u_int32_t)ntohl(sav->spi)));
                IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
                m_freem(m);
                return EINVAL;
        }

        algo = ah_algorithm_lookup(sav->alg_auth);
        if (!algo) {
                ipseclog((LOG_ERR, "ah4_output: unsupported algorithm: "
                    "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
                IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
                m_freem(m);
                return EINVAL;
        }
        spi = sav->spi;

        /*
         * determine the size to grow.
         */
        if (sav->flags & SADB_X_EXT_OLD) {
                /* RFC 1826 */
                plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
                ahlen = plen + sizeof(struct ah);
        } else {
                /* RFC 2402 */
                plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1); /*XXX pad to 8byte?*/
                ahlen = plen + sizeof(struct newah);
        }

        VERIFY(ahlen <= UINT16_MAX);

        /*
         * grow the mbuf to accomodate AH.
         */
        ip = mtod(m, struct ip *);
#ifdef _IP_VHL
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
        hlen = ip->ip_hl << 2;
#endif

        if (m->m_len != hlen) {
                panic("ah4_output: assumption failed (first mbuf length)");
        }
        if (M_LEADINGSPACE(m->m_next) < ahlen) {
                struct mbuf *n;
                MGET(n, M_DONTWAIT, MT_DATA);
                if (!n) {
                        ipseclog((LOG_DEBUG, "ENOBUFS in ah4_output %d\n",
                            __LINE__));
                        m_freem(m);
                        return ENOBUFS;
                }
                n->m_len = (int32_t)ahlen;
                n->m_next = m->m_next;
                m->m_next = n;
                m->m_pkthdr.len += ahlen;
                ahdrpos = mtod(n, u_char *);
        } else {
                m->m_next->m_len += ahlen;
                m->m_next->m_data -= ahlen;
                m->m_pkthdr.len += ahlen;
                ahdrpos = mtod(m->m_next, u_char *);
        }

        ip = mtod(m, struct ip *);      /*just to be sure*/

        /*
         * initialize AH.
         */
        if (sav->flags & SADB_X_EXT_OLD) {
                struct ah *ahdr;

                VERIFY((plen >> 2) <= UINT8_MAX);
                ahdr = (struct ah *)(void *)ahdrpos;
                ahsumpos = (u_char *)(ahdr + 1);
                ahdr->ah_len = (u_int8_t)(plen >> 2);
                ahdr->ah_nxt = ip->ip_p;
                ahdr->ah_reserve = htons(0);
                ahdr->ah_spi = spi;
                bzero(ahdr + 1, plen);
        } else {
                struct newah *ahdr;

                VERIFY(((plen >> 2) + 1) <= UINT8_MAX);
                ahdr = (struct newah *)(void *)ahdrpos;
                ahsumpos = (u_char *)(ahdr + 1);
                ahdr->ah_len = (u_int8_t)((plen >> 2) + 1); /* plus one for seq# */
                ahdr->ah_nxt = ip->ip_p;
                ahdr->ah_reserve = htons(0);
                ahdr->ah_spi = spi;
                if (sav->replay[0]->count == ~0) {
                        if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
                                /* XXX Is it noisy ? */
                                ipseclog((LOG_WARNING,
                                    "replay counter overflowed. %s\n",
                                    ipsec_logsastr(sav)));
                                IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
                                m_freem(m);
                                return EINVAL;
                        }
                }
                lck_mtx_lock(sadb_mutex);
                sav->replay[0]->count++;
                lck_mtx_unlock(sadb_mutex);
                /*
                 * XXX sequence number must not be cycled, if the SA is
                 * installed by IKE daemon.
                 */
                ahdr->ah_seq = htonl(sav->replay[0]->count);
                bzero(ahdr + 1, plen);
        }

        /*
         * modify IPv4 header.
         */
        ip->ip_p = IPPROTO_AH;
        if (ahlen < (IP_MAXPACKET - ntohs(ip->ip_len))) {
                ip->ip_len = htons(ntohs(ip->ip_len) + (u_int16_t)ahlen);
        } else {
                ipseclog((LOG_ERR, "IPv4 AH output: size exceeds limit\n"));
                IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
                m_freem(m);
                return EMSGSIZE;
        }

        /*
         * If there is source routing option, update destination field in
         * the IPv4 header to the final destination.
         * Note that we do not need to update source routing option itself
         * (as done in IPv4 AH processing -- see ip6_output()), since
         * source routing option is not part of the ICV computation.
         */
        finaldst = ah4_finaldst(m);
        if (finaldst) {
                dst.s_addr = ip->ip_dst.s_addr;
                ip->ip_dst.s_addr = finaldst->s_addr;
        }

        /*
         * calcurate the checksum, based on security association
         * and the algorithm specified.
         */
        error = ah4_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
        if (error) {
                ipseclog((LOG_ERR,
                    "error after ah4_calccksum, called from ah4_output"));
                m_freem(m);
                m = NULL;
                IPSEC_STAT_INCREMENT(ipsecstat.out_inval);
                return error;
        }

        if (finaldst) {
                ip = mtod(m, struct ip *);      /*just to make sure*/
                ip->ip_dst.s_addr = dst.s_addr;
        }
        lck_mtx_lock(sadb_stat_mutex);
        ipsecstat.out_success++;
        ipsecstat.out_ahhist[sav->alg_auth]++;
        lck_mtx_unlock(sadb_stat_mutex);
        key_sa_recordxfer(sav, m);

        return 0;
}
#endif

/* Calculate AH length */
size_t
ah_hdrlen(struct secasvar *sav)
{
        const struct ah_algorithm *algo;
        size_t plen, ahlen;

        algo = ah_algorithm_lookup(sav->alg_auth);
        if (!algo) {
                return 0;
        }
        if (sav->flags & SADB_X_EXT_OLD) {
                /* RFC 1826 */
                plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
                ahlen = plen + sizeof(struct ah);
        } else {
                /* RFC 2402 */
                plen = ((*algo->sumsiz)(sav) + 3) & ~(4 - 1);   /*XXX pad to 8byte?*/
                ahlen = plen + sizeof(struct newah);
        }

        return ahlen;
}

/*
 * Fill in the Authentication Header and calculate checksum.
 */
int
ah6_output(struct mbuf *m, u_char *nexthdrp, struct mbuf *md,
    struct secasvar *sav)
{
        struct mbuf *mprev;
        struct mbuf *mah;
        const struct ah_algorithm *algo;
        u_int32_t spi;
        u_char *ahsumpos = NULL;
        size_t plen;    /*AH payload size in bytes*/
        int error = 0;
        size_t ahlen;
        struct ip6_hdr *ip6;

        if (m->m_len < sizeof(struct ip6_hdr)) {
                ipseclog((LOG_DEBUG, "ah6_output: first mbuf too short\n"));
                m_freem(m);
                return EINVAL;
        }

        ahlen = ah_hdrlen(sav);
        if (ahlen == 0) {
                return 0;
        }

        VERIFY(ahlen <= UINT16_MAX);

        for (mprev = m; mprev && mprev->m_next != md; mprev = mprev->m_next) {
                ;
        }
        if (!mprev || mprev->m_next != md) {
                ipseclog((LOG_DEBUG, "ah6_output: md is not in chain\n"));
                m_freem(m);
                return EINVAL;
        }

        MGET(mah, M_DONTWAIT, MT_DATA);
        if (!mah) {
                m_freem(m);
                return ENOBUFS;
        }
        if (ahlen > MLEN) {
                MCLGET(mah, M_DONTWAIT);
                if ((mah->m_flags & M_EXT) == 0) {
                        m_free(mah);
                        m_freem(m);
                        return ENOBUFS;
                }
        }
        mah->m_len = (int32_t)ahlen;
        mah->m_next = md;
        mprev->m_next = mah;
        m->m_pkthdr.len += ahlen;

        /* fix plen */
        if (m->m_pkthdr.len - sizeof(struct ip6_hdr) > IPV6_MAXPACKET) {
                ipseclog((LOG_ERR,
                    "ip6_output: AH with IPv6 jumbogram is not supported\n"));
                m_freem(m);
                return EINVAL;
        }

        ip6 = mtod(m, struct ip6_hdr *);
        ip6->ip6_plen = htons((u_int16_t)(m->m_pkthdr.len - sizeof(struct ip6_hdr)));

        if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay[0] == NULL) {
                ipseclog((LOG_DEBUG, "ah6_output: internal error: "
                    "sav->replay is null: SPI=%u\n",
                    (u_int32_t)ntohl(sav->spi)));
                IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
                m_freem(m);
                return EINVAL;
        }

        algo = ah_algorithm_lookup(sav->alg_auth);
        if (!algo) {
                ipseclog((LOG_ERR, "ah6_output: unsupported algorithm: "
                    "SPI=%u\n", (u_int32_t)ntohl(sav->spi)));
                IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
                m_freem(m);
                return EINVAL;
        }
        spi = sav->spi;

        /*
         * initialize AH.
         */
        if (sav->flags & SADB_X_EXT_OLD) {
                struct ah *ahdr = mtod(mah, struct ah *);

                plen = mah->m_len - sizeof(struct ah);
                VERIFY((plen >> 2) <= UINT8_MAX);
                ahsumpos = (u_char *)(ahdr + 1);
                ahdr->ah_nxt = *nexthdrp;
                *nexthdrp = IPPROTO_AH;
                ahdr->ah_len = (u_int8_t)(plen >> 2);
                ahdr->ah_reserve = htons(0);
                ahdr->ah_spi = spi;
                bzero(ahdr + 1, plen);
        } else {
                struct newah *ahdr = mtod(mah, struct newah *);

                plen = mah->m_len - sizeof(struct newah);
                VERIFY(((plen >> 2) + 1) <= UINT8_MAX);
                ahsumpos = (u_char *)(ahdr + 1);
                ahdr->ah_nxt = *nexthdrp;
                *nexthdrp = IPPROTO_AH;
                ahdr->ah_len = (u_int8_t)((plen >> 2) + 1); /* plus one for seq# */
                ahdr->ah_reserve = htons(0);
                ahdr->ah_spi = spi;
                if (sav->replay[0]->count == ~0) {
                        if ((sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
                                /* XXX Is it noisy ? */
                                ipseclog((LOG_WARNING,
                                    "replay counter overflowed. %s\n",
                                    ipsec_logsastr(sav)));
                                IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
                                m_freem(m);
                                return EINVAL;
                        }
                }
                lck_mtx_lock(sadb_mutex);
                sav->replay[0]->count++;
                lck_mtx_unlock(sadb_mutex);
                /*
                 * XXX sequence number must not be cycled, if the SA is
                 * installed by IKE daemon.
                 */
                ahdr->ah_seq = htonl(sav->replay[0]->count);
                bzero(ahdr + 1, plen);
        }

        /*
         * calcurate the checksum, based on security association
         * and the algorithm specified.
         */
        error = ah6_calccksum(m, (caddr_t)ahsumpos, plen, algo, sav);
        if (error) {
                IPSEC_STAT_INCREMENT(ipsec6stat.out_inval);
                m_freem(m);
        } else {
                IPSEC_STAT_INCREMENT(ipsec6stat.out_success);
                key_sa_recordxfer(sav, m);
        }
        IPSEC_STAT_INCREMENT(ipsec6stat.out_ahhist[sav->alg_auth]);

        return error;
}

/*
 * Find the final destination if there is loose/strict source routing option.
 * Returns NULL if there's no source routing options.
 * Returns NULL on errors too.
 * Note that this function will return a pointer INTO the given parameter,
 * struct mbuf *m.
 * The mbuf must be pulled up toward, at least, ip option part.
 */
static struct in_addr *
ah4_finaldst(struct mbuf *m)
{
        struct ip *ip;
        int optlen;
        u_char *q;
        int i;
        int hlen;

        if (!m) {
                panic("ah4_finaldst: m == NULL");
        }
        ip = mtod(m, struct ip *);
#ifdef _IP_VHL
        hlen = IP_VHL_HL(ip->ip_vhl) << 2;
#else
        hlen = ip->ip_hl << 2;
#endif

        if (m->m_len < hlen) {
                ipseclog((LOG_DEBUG,
                    "ah4_finaldst: parameter mbuf wrong (not pulled up)\n"));
                return NULL;
        }

        if (hlen == sizeof(struct ip)) {
                return NULL;
        }

        optlen = hlen - sizeof(struct ip);
        if (optlen < 0) {
                ipseclog((LOG_DEBUG, "ah4_finaldst: wrong optlen %d\n",
                    optlen));
                return NULL;
        }

        q = (u_char *)(ip + 1);
        i = 0;
        while (i < optlen) {
                if (i + IPOPT_OPTVAL >= optlen) {
                        return NULL;
                }
                if (q[i + IPOPT_OPTVAL] == IPOPT_EOL ||
                    q[i + IPOPT_OPTVAL] == IPOPT_NOP ||
                    i + IPOPT_OLEN < optlen) {
                        ;
                } else {
                        return NULL;
                }

                switch (q[i + IPOPT_OPTVAL]) {
                case IPOPT_EOL:
                        i = optlen;     /* bye */
                        break;
                case IPOPT_NOP:
                        i++;
                        break;
                case IPOPT_LSRR:
                case IPOPT_SSRR:
                        if (q[i + IPOPT_OLEN] < 2 + sizeof(struct in_addr) ||
                            optlen - i < q[i + IPOPT_OLEN]) {
                                ipseclog((LOG_ERR,
                                    "ip_finaldst: invalid IP option "
                                    "(code=%02x len=%02x)\n",
                                    q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
                                return NULL;
                        }
                        i += q[i + IPOPT_OLEN] - sizeof(struct in_addr);
                        return (struct in_addr *)(void *)(q + i);
                default:
                        if (q[i + IPOPT_OLEN] < 2 ||
                            optlen - i < q[i + IPOPT_OLEN]) {
                                ipseclog((LOG_ERR,
                                    "ip_finaldst: invalid IP option "
                                    "(code=%02x len=%02x)\n",
                                    q[i + IPOPT_OPTVAL], q[i + IPOPT_OLEN]));
                                return NULL;
                        }
                        i += q[i + IPOPT_OLEN];
                        break;
                }
        }
        return NULL;
}