/* $OpenBSD: ip_esp_new.c,v 1.46 1999/10/06 22:27:57 jason Exp $ */ /* * The authors of this code are John Ioannidis (ji@tla.org), * Angelos D. Keromytis (kermit@csd.uch.gr) and * Niels Provos (provos@physnet.uni-hamburg.de). * * This code was written by John Ioannidis for BSD/OS in Athens, Greece, * in November 1995. * * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, * by Angelos D. Keromytis. * * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis * and Niels Provos. * * Additional features in 1999 by Angelos D. Keromytis. * * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, * Angelos D. Keromytis and Niels Provos. * * Permission to use, copy, and modify this software without fee * is hereby granted, provided that this entire notice is included in * all copies of any software which is or includes a copy or * modification of this software. * You may use this code under the GNU public license if you so wish. Please * contribute changes back to the authors under this freer than GPL license * so that we may further the use of strong encryption without limitations to * all. * * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR * PURPOSE. */ /* * Based on draft-ietf-ipsec-esp-v2-00.txt and * draft-ietf-ipsec-ciph-{des,3des}-{derived,expiv}-00.txt */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef ENCDEBUG #define DPRINTF(x) if (encdebug) printf x #else #define DPRINTF(x) #endif extern struct auth_hash auth_hash_hmac_md5_96; extern struct auth_hash auth_hash_hmac_sha1_96; extern struct auth_hash auth_hash_hmac_ripemd_160_96; struct auth_hash *esp_new_hash[] = { &auth_hash_hmac_md5_96, &auth_hash_hmac_sha1_96, &auth_hash_hmac_ripemd_160_96 }; extern struct enc_xform enc_xform_des; extern struct enc_xform enc_xform_3des; extern struct enc_xform enc_xform_blf; extern struct enc_xform enc_xform_cast5; extern struct enc_xform enc_xform_skipjack; struct enc_xform *esp_new_xform[] = { &enc_xform_des, &enc_xform_3des, &enc_xform_blf, &enc_xform_cast5, &enc_xform_skipjack, }; /* * esp_new_attach() is called from the transformation initialization code. */ int esp_new_attach() { return 0; } /* * esp_new_init() is called when an SPI is being set up. */ int esp_new_init(struct tdb *tdbp, struct xformsw *xsp, struct ipsecinit *ii) { struct enc_xform *txform = NULL; struct auth_hash *thash = NULL; int i; /* Check whether the encryption algorithm is supported */ for (i = sizeof(esp_new_xform) / sizeof(esp_new_xform[0]) - 1; i >= 0; i--) if (ii->ii_encalg == esp_new_xform[i]->type) break; if (i < 0) { DPRINTF(("esp_new_init(): unsupported encryption algorithm %d specified\n", ii->ii_encalg)); return EINVAL; } txform = esp_new_xform[i]; if (ii->ii_enckeylen < txform->minkey) { DPRINTF(("esp_new_init(): keylength %d too small (min length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->minkey, txform->name)); return EINVAL; } if (ii->ii_enckeylen > txform->maxkey) { DPRINTF(("esp_new_init(): keylength %d too large (max length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->maxkey, txform->name)); return EINVAL; } if (ii->ii_authalg) { for (i = sizeof(esp_new_hash) / sizeof(esp_new_hash[0]) - 1; i >= 0; i--) if (ii->ii_authalg == esp_new_hash[i]->type) break; if (i < 0) { DPRINTF(("esp_new_init(): unsupported authentication algorithm %d specified\n", ii->ii_authalg)); return EINVAL; } thash = esp_new_hash[i]; if (ii->ii_authkeylen != thash->keysize) { DPRINTF(("esp_new_init(): keylength %d doesn't match algorithm %s keysize (%d)\n", ii->ii_authkeylen, thash->name, thash->keysize)); return EINVAL; } tdbp->tdb_authalgxform = thash; DPRINTF(("esp_new_init(): initialized TDB with hash algorithm %s\n", thash->name)); } tdbp->tdb_xform = xsp; tdbp->tdb_encalgxform = txform; tdbp->tdb_bitmap = 0; tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL; DPRINTF(("esp_new_init(): initialized TDB with enc algorithm %s\n", txform->name)); tdbp->tdb_ivlen = txform->ivmask; /* Initialize the IV */ get_random_bytes(tdbp->tdb_iv, tdbp->tdb_ivlen); if (txform->setkey) txform->setkey(&tdbp->tdb_key, ii->ii_enckey, ii->ii_enckeylen); if (thash) { /* Precompute the I and O pads of the HMAC */ for (i = 0; i < ii->ii_authkeylen; i++) ii->ii_authkey[i] ^= HMAC_IPAD_VAL; MALLOC(tdbp->tdb_ictx, u_int8_t *, thash->ctxsize, M_XDATA, M_WAITOK); bzero(tdbp->tdb_ictx, thash->ctxsize); thash->Init(tdbp->tdb_ictx); thash->Update(tdbp->tdb_ictx, ii->ii_authkey, ii->ii_authkeylen); thash->Update(tdbp->tdb_ictx, hmac_ipad_buffer, HMAC_BLOCK_LEN - ii->ii_authkeylen); for (i = 0; i < ii->ii_authkeylen; i++) ii->ii_authkey[i] ^= (HMAC_IPAD_VAL ^ HMAC_OPAD_VAL); MALLOC(tdbp->tdb_octx, u_int8_t *, thash->ctxsize, M_XDATA, M_WAITOK); bzero(tdbp->tdb_octx, thash->ctxsize); thash->Init(tdbp->tdb_octx); thash->Update(tdbp->tdb_octx, ii->ii_authkey, ii->ii_authkeylen); thash->Update(tdbp->tdb_octx, hmac_opad_buffer, HMAC_BLOCK_LEN - ii->ii_authkeylen); } return 0; } int esp_new_zeroize(struct tdb *tdbp) { if (tdbp->tdb_key && tdbp->tdb_encalgxform && tdbp->tdb_encalgxform->zerokey) tdbp->tdb_encalgxform->zerokey(&tdbp->tdb_key); if (tdbp->tdb_ictx) { if (tdbp->tdb_authalgxform) bzero(tdbp->tdb_ictx, tdbp->tdb_authalgxform->ctxsize); FREE(tdbp->tdb_ictx, M_XDATA); tdbp->tdb_ictx = NULL; } if (tdbp->tdb_octx) { if (tdbp->tdb_authalgxform) bzero(tdbp->tdb_octx, tdbp->tdb_authalgxform->ctxsize); FREE(tdbp->tdb_octx, M_XDATA); tdbp->tdb_octx = NULL; } return 0; } struct mbuf * esp_new_input(struct mbuf *m, struct tdb *tdb) { struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform; struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform; u_char iv[ESP_MAX_IVS], niv[ESP_MAX_IVS]; u_char blk[ESP_MAX_BLKS], *lblk, opts[40]; int ohlen, oplen, plen, alen, ilen, i, blks, rest; int count, off, errc; struct mbuf *mi, *mo; u_char *idat, *odat, *ivp, *ivn; struct esp_new *esp; struct ip *ip, ipo; u_int32_t btsx; union authctx ctx; u_char buf[AH_ALEN_MAX], buf2[AH_ALEN_MAX]; blks = espx->blocksize; if (esph) alen = AH_HMAC_HASHLEN; else alen = 0; if (m->m_len < sizeof(struct ip)) { if ((m = m_pullup(m, sizeof(struct ip))) == NULL) { DPRINTF(("esp_new_input(): (possibly too short) packet dropped\n")); espstat.esps_hdrops++; return NULL; } } ip = mtod(m, struct ip *); ohlen = (ip->ip_hl << 2) + ESP_NEW_FLENGTH; /* Make sure the IP header, any IP options, and the ESP header are here */ if (m->m_len < ohlen + blks) { if ((m = m_pullup(m, ohlen + blks)) == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed\n")); espstat.esps_hdrops++; return NULL; } ip = mtod(m, struct ip *); } /* Update the counters */ tdb->tdb_cur_bytes += ip->ip_len - ohlen - alen; espstat.esps_ibytes += ip->ip_len - ohlen - alen; /* Hard expiration */ if ((tdb->tdb_flags & TDBF_BYTES) && (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) { pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); tdb_delete(tdb, 0, TDBEXP_TIMEOUT); m_freem(m); return NULL; } /* Notify on expiration */ if ((tdb->tdb_flags & TDBF_SOFT_BYTES) && (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) { pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */ } esp = (struct esp_new *) ((u_int8_t *) ip + (ip->ip_hl << 2)); ipo = *ip; /* Replay window checking */ if (tdb->tdb_wnd > 0) { btsx = ntohl(esp->esp_rpl); if ((errc = checkreplaywindow32(btsx, 0, &(tdb->tdb_rpl), tdb->tdb_wnd, &(tdb->tdb_bitmap))) != 0) { switch(errc) { case 1: DPRINTF(("esp_new_input(): replay counter wrapped for packets from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi))); espstat.esps_wrap++; break; case 2: case 3: DPRINTF(("esp_new_input(): duplicate packet received from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi))); espstat.esps_replay++; break; } m_freem(m); return NULL; } } /* Skip the IP header, IP options, SPI, SN and IV and minus Auth Data */ plen = m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - tdb->tdb_ivlen - alen; if ((plen & (blks - 1)) || (plen <= 0)) { DPRINTF(("esp_new_input(): payload not a multiple of %d octets for packet from %s to %s, spi %08x\n", blks, inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return NULL; } if (esph) { bcopy(tdb->tdb_ictx, &ctx, esph->ctxsize); /* Auth covers SPI + SN + IV */ oplen = plen + 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; off = (ip->ip_hl << 2); /* Copy the authentication data */ m_copydata(m, m->m_pkthdr.len - alen, alen, buf); mo = m; while (oplen > 0) { if (mo == 0) { DPRINTF(("esp_new_input(): bad mbuf chain for packet from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi))); espstat.esps_hdrops++; m_freem(m); return NULL; } count = min(mo->m_len - off, oplen); esph->Update(&ctx, mtod(mo, unsigned char *) + off, count); oplen -= count; off = 0; mo = mo->m_next; } esph->Final(buf2, &ctx); bcopy(tdb->tdb_octx, &ctx, esph->ctxsize); esph->Update(&ctx, buf2, esph->hashsize); esph->Final(buf2, &ctx); if (bcmp(buf2, buf, AH_HMAC_HASHLEN)) { DPRINTF(("esp_new_input(): authentication failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ip->ip_src), inet_ntoa4(ip->ip_dst), ntohl(esp->esp_spi))); espstat.esps_badauth++; m_freem(m); return NULL; } } oplen = plen; ilen = m->m_len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t); idat = mtod(m, unsigned char *) + (ip->ip_hl << 2) + 2 * sizeof(u_int32_t); bcopy(idat, iv, tdb->tdb_ivlen); ilen -= tdb->tdb_ivlen; idat += tdb->tdb_ivlen; mi = m; /* * At this point: * plen is # of encapsulated payload octets * ilen is # of octets left in this mbuf * idat is first encapsulated payload octed in this mbuf * same for olen and odat * ivp points to the IV, ivn buffers the next IV. * mi points to the first mbuf * * From now on until the end of the mbuf chain: * . move the next eight octets of the chain into ivn * . decrypt idat and xor with ivp * . swap ivp and ivn. * . repeat */ ivp = iv; ivn = niv; rest = ilen % blks; while (plen > 0) /* while not done */ { if (ilen < blks) { if (rest) { bcopy(idat, blk, rest); odat = idat; } do { mi = (mo = mi)->m_next; if (mi == NULL) { DPRINTF(("esp_new_input(): bad mbuf chain, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; m_freem(m); return NULL; } } while (mi->m_len == 0); if (mi->m_len < blks - rest) { if ((mi = m_pullup(mi, blks - rest)) == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_hdrops++; return NULL; } /* * m_pullup was not called at the beginning of the chain * but might return a new mbuf, link it into the chain. */ mo->m_next = mi; } ilen = mi->m_len; idat = mtod(mi, u_char *); if (rest) { bcopy(idat, blk + rest, blks - rest); bcopy(blk, ivn, blks); espx->decrypt(tdb, blk); for (i = 0; i < blks; i++) blk[i] ^= ivp[i]; ivp = ivn; ivn = (ivp == iv) ? niv : iv; bcopy(blk, odat, rest); bcopy(blk + rest, idat, blks - rest); lblk = blk; /* last block touched */ idat += blks - rest; ilen -= blks - rest; plen -= blks; } rest = ilen % blks; } while (ilen >= blks && plen > 0) { bcopy(idat, ivn, blks); espx->decrypt(tdb, idat); for (i = 0; i < blks; i++) idat[i] ^= ivp[i]; ivp = ivn; ivn = (ivp == iv) ? niv : iv; lblk = idat; /* last block touched */ idat += blks; ilen -= blks; plen -= blks; } } /* Save the options */ m_copydata(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip), (caddr_t) opts); if (lblk != blk) bcopy(lblk, blk, blks); /* * Now, the entire chain has been decrypted. As a side effect, * blk[blks - 1] contains the next protocol, and blk[blks - 2] contains * the amount of padding the original chain had. Chop off the * appropriate parts of the chain, and return. * Verify correct decryption by checking the last padding bytes. */ if (blk[blks - 2] + 2 + alen > m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - tdb->tdb_ivlen) { DPRINTF(("esp_new_input(): invalid padding length %d for packet from %s to %s, spi %08x\n", blk[blks - 2], inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return NULL; } if ((blk[blks - 2] != blk[blks - 3]) && (blk[blks - 2] != 0)) { DPRINTF(("esp_new_input(): decryption failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi))); m_freem(m); return NULL; } m_adj(m, - blk[blks - 2] - 2 - alen); /* Old type padding */ m_adj(m, 2 * sizeof(u_int32_t) + tdb->tdb_ivlen); if (m->m_len < (ipo.ip_hl << 2)) { m = m_pullup(m, (ipo.ip_hl << 2)); if (m == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed for packet from %s to %s, spi %08x\n", inet_ntoa4(ipo.ip_src), inet_ntoa4(ipo.ip_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; return NULL; } } ip = mtod(m, struct ip *); ipo.ip_p = blk[blks - 1]; ipo.ip_id = htons(ipo.ip_id); ipo.ip_off = 0; ipo.ip_len += (ipo.ip_hl << 2) - 2 * sizeof(u_int32_t) - tdb->tdb_ivlen - blk[blks - 2] - 2 - alen; ipo.ip_len = htons(ipo.ip_len); ipo.ip_sum = 0; *ip = ipo; /* Copy the options back */ m_copyback(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip), (caddr_t) opts); ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); return m; } int esp_new_output(struct mbuf *m, struct sockaddr_encap *gw, struct tdb *tdb, struct mbuf **mp) { struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform; struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform; struct ip *ip, ipo; int i, ilen, ohlen, nh, rlen, plen, padding, rest; struct esp_new espo; struct mbuf *mi, *mo = (struct mbuf *) NULL; u_char *pad, *idat, *odat, *ivp; u_char iv[ESP_MAX_IVS], blk[ESP_MAX_BLKS], auth[AH_ALEN_MAX], opts[40]; union authctx ctx; int iphlen, blks, alen; blks = espx->blocksize; if (esph) alen = AH_HMAC_HASHLEN; else alen = 0; espstat.esps_output++; /* * Loop through mbuf chain; if we find an M_EXT mbuf with * more than one reference, replace the rest of the chain. */ mi = m; while (mi != NULL && (!(mi->m_flags & M_EXT) || (mi->m_ext.ext_ref == NULL && mclrefcnt[mtocl(mi->m_ext.ext_buf)] <= 1))) { mo = mi; mi = mi->m_next; } if (mi != NULL) { /* Replace the rest of the mbuf chain. */ struct mbuf *n = m_copym2(mi, 0, M_COPYALL, M_DONTWAIT); if (n == NULL) { espstat.esps_hdrops++; m_freem(m); return ENOBUFS; } if (mo != NULL) mo->m_next = n; else m = n; m_freem(mi); } m = m_pullup(m, sizeof (struct ip)); /* Get IP header in one mbuf */ if (m == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; return ENOBUFS; } if (tdb->tdb_rpl == 0) { DPRINTF(("esp_new_output(): SA %s/%0x8 should have expired\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_wrap++; return ENOBUFS; } espo.esp_spi = tdb->tdb_spi; espo.esp_rpl = htonl(tdb->tdb_rpl++); ip = mtod(m, struct ip *); iphlen = (ip->ip_hl << 2); /* Update the counters */ tdb->tdb_cur_bytes += ntohs(ip->ip_len) - (ip->ip_hl << 2); espstat.esps_obytes += ntohs(ip->ip_len) - (ip->ip_hl << 2); /* Hard expiration */ if ((tdb->tdb_flags & TDBF_BYTES) && (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes)) { pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_HARD); tdb_delete(tdb, 0, TDBEXP_TIMEOUT); m_freem(m); return EINVAL; } /* Notify on expiration */ if ((tdb->tdb_flags & TDBF_SOFT_BYTES) && (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes)) { pfkeyv2_expire(tdb, SADB_EXT_LIFETIME_SOFT); tdb->tdb_flags &= ~TDBF_SOFT_BYTES; /* Turn off checking */ } /* * If options are present, pullup the IP header, the options. */ if (iphlen != sizeof(struct ip)) { m = m_pullup(m, iphlen + 8); if (m == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; return ENOBUFS; } ip = mtod(m, struct ip *); /* Keep the options */ m_copydata(m, sizeof(struct ip), iphlen - sizeof(struct ip), (caddr_t) opts); } ilen = ntohs(ip->ip_len); /* Size of the packet */ ohlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; ipo = *ip; nh = ipo.ip_p; /* Raw payload length */ rlen = ilen - iphlen; padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; if (iphlen + ohlen + rlen + padding + alen > IP_MAXPACKET) { DPRINTF(("esp_new_output(): packet in SA %s/%0x8 got too big\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_toobig++; return EMSGSIZE; } pad = (u_char *) m_pad(m, padding + alen, 0); if (pad == NULL) { DPRINTF(("esp_new_output(): m_pad() failed for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); return ENOBUFS; } /* Self describing padding */ for (i = 0; i < padding - 2; i++) pad[i] = i + 1; pad[padding - 2] = padding - 2; pad[padding - 1] = nh; mi = m; plen = rlen + padding; ilen = m->m_len - iphlen; idat = mtod(m, u_char *) + iphlen; bcopy(tdb->tdb_iv, iv, tdb->tdb_ivlen); bcopy(tdb->tdb_iv, espo.esp_iv, tdb->tdb_ivlen); /* Authenticate the esp header */ if (esph) { bcopy(tdb->tdb_ictx, &ctx, esph->ctxsize); esph->Update(&ctx, (unsigned char *) &espo, 2 * sizeof(u_int32_t) + tdb->tdb_ivlen); } /* Encrypt the payload */ ivp = iv; rest = ilen % blks; while (plen > 0) /* while not done */ { if (ilen < blks) { if (rest) { if (ivp == blk) { bcopy(blk, iv, blks); ivp = iv; } bcopy(idat, blk, rest); odat = idat; } do { mi = (mo = mi)->m_next; if (mi == NULL) { DPRINTF(("esp_new_output(): bad mbuf chain, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; m_freem(m); return EINVAL; } } while (mi->m_len == 0); if (mi->m_len < blks - rest) { if ((mi = m_pullup(mi, blks - rest)) == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_hdrops++; return ENOBUFS; } /* * m_pullup was not called at the beginning of the chain * but might return a new mbuf, link it into the chain. */ mo->m_next = mi; } ilen = mi->m_len; idat = mtod(mi, u_char *); if (rest) { bcopy(idat, blk + rest, blks - rest); for (i = 0; i < blks; i++) blk[i] ^= ivp[i]; espx->encrypt(tdb, blk); if (esph) esph->Update(&ctx, blk, blks); ivp = blk; bcopy(blk, odat, rest); bcopy(blk + rest, idat, blks - rest); idat += blks - rest; ilen -= blks - rest; plen -= blks; } rest = ilen % blks; } while (ilen >= blks && plen > 0) { for (i = 0; i < blks; i++) idat[i] ^= ivp[i]; espx->encrypt(tdb, idat); if (esph) esph->Update(&ctx, idat, blks); ivp = idat; idat += blks; ilen -= blks; plen -= blks; } } /* Put in authentication data */ if (esph) { esph->Final(auth, &ctx); bcopy(tdb->tdb_octx, &ctx, esph->ctxsize); esph->Update(&ctx, auth, esph->hashsize); esph->Final(auth, &ctx); /* Copy the final authenticator */ bcopy(auth, pad + padding, alen); } /* * Done with encryption. Let's wedge in the ESP header * and send it out. */ M_PREPEND(m, ohlen, M_DONTWAIT); if (m == NULL) { DPRINTF(("esp_new_output(): M_PREPEND failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); return ENOBUFS; } m = m_pullup(m, iphlen + ohlen); if (m == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; return ENOBUFS; } /* Fix the length and the next protocol, copy back and off we go */ ipo.ip_len = htons(iphlen + ohlen + rlen + padding + alen); ipo.ip_p = IPPROTO_ESP; /* Save the last encrypted block, to be used as the next IV */ bcopy(ivp, tdb->tdb_iv, tdb->tdb_ivlen); m_copyback(m, 0, sizeof(struct ip), (caddr_t) &ipo); /* Copy options, if existing */ if (iphlen != sizeof(struct ip)) m_copyback(m, sizeof(struct ip), iphlen - sizeof(struct ip), (caddr_t) opts); /* Copy in the esp header */ m_copyback(m, iphlen, ohlen, (caddr_t) &espo); *mp = m; return 0; } /* * return 0 on success * return 1 for counter == 0 * return 2 for very old packet * return 3 for packet within current window but already received */ int checkreplaywindow32(u_int32_t seq, u_int32_t initial, u_int32_t *lastseq, u_int32_t window, u_int32_t *bitmap) { u_int32_t diff; seq -= initial; if (seq == 0) return 1; if (seq > *lastseq - initial) { diff = seq - (*lastseq - initial); if (diff < window) *bitmap = ((*bitmap) << diff) | 1; else *bitmap = 1; *lastseq = seq + initial; return 0; } diff = *lastseq - initial - seq; if (diff >= window) { espstat.esps_wrap++; return 2; } if ((*bitmap) & (((u_int32_t) 1) << diff)) { espstat.esps_replay++; return 3; } *bitmap |= (((u_int32_t) 1) << diff); return 0; }