/* $OpenBSD: ip_esp.c,v 1.49 2000/09/19 03:20:58 angelos 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). * * The original version of 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. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET #include #include #include #endif /* INET */ #ifdef INET6 #ifndef INET #include #endif #include #endif /* INET6 */ #include #include #include #include #include #include #include #include #include #include "bpfilter.h" #ifdef ENCDEBUG #define DPRINTF(x) if (encdebug) printf x #else #define DPRINTF(x) #endif #ifndef offsetof #define offsetof(s, e) ((int)&((s *)0)->e) #endif /* * esp_attach() is called from the transformation initialization code. */ int esp_attach() { return 0; } /* * esp_init() is called when an SPI is being set up. */ int esp_init(struct tdb *tdbp, struct xformsw *xsp, struct ipsecinit *ii) { struct enc_xform *txform = NULL; struct auth_hash *thash = NULL; struct cryptoini cria, crie; if (ii->ii_encalg) { switch (ii->ii_encalg) { case SADB_EALG_DESCBC: txform = &enc_xform_des; break; case SADB_EALG_3DESCBC: txform = &enc_xform_3des; break; case SADB_X_EALG_BLF: txform = &enc_xform_blf; break; case SADB_X_EALG_CAST: txform = &enc_xform_cast5; break; case SADB_X_EALG_SKIPJACK: txform = &enc_xform_skipjack; break; default: DPRINTF(("esp_init(): unsupported encryption algorithm %d specified\n", ii->ii_encalg)); return EINVAL; } if (ii->ii_enckeylen < txform->minkey) { DPRINTF(("esp_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_init(): keylength %d too large (max length is %d) for algorithm %s\n", ii->ii_enckeylen, txform->maxkey, txform->name)); return EINVAL; } tdbp->tdb_encalgxform = txform; DPRINTF(("esp_init(): initialized TDB with enc algorithm %s\n", txform->name)); tdbp->tdb_ivlen = txform->ivmask; if (tdbp->tdb_flags & TDBF_HALFIV) tdbp->tdb_ivlen /= 2; } if (ii->ii_authalg) { switch (ii->ii_authalg) { case SADB_AALG_MD5HMAC96: thash = &auth_hash_hmac_md5_96; break; case SADB_AALG_SHA1HMAC96: thash = &auth_hash_hmac_sha1_96; break; case SADB_X_AALG_RIPEMD160HMAC96: thash = &auth_hash_hmac_ripemd_160_96; break; default: DPRINTF(("esp_init(): unsupported authentication algorithm %d specified\n", ii->ii_authalg)); return EINVAL; } if (ii->ii_authkeylen != thash->keysize) { DPRINTF(("esp_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_init(): initialized TDB with hash algorithm %s\n", thash->name)); } tdbp->tdb_xform = xsp; tdbp->tdb_bitmap = 0; tdbp->tdb_rpl = AH_HMAC_INITIAL_RPL; /* Initialize crypto session */ if (tdbp->tdb_encalgxform) { /* Save the raw keys */ tdbp->tdb_emxkeylen = ii->ii_enckeylen; MALLOC(tdbp->tdb_emxkey, u_int8_t *, tdbp->tdb_emxkeylen, M_XDATA, M_WAITOK); bcopy(ii->ii_enckey, tdbp->tdb_emxkey, tdbp->tdb_emxkeylen); bzero(&crie, sizeof(crie)); crie.cri_alg = tdbp->tdb_encalgxform->type; if (tdbp->tdb_authalgxform) crie.cri_next = &cria; else crie.cri_next = NULL; crie.cri_klen = ii->ii_enckeylen * 8; crie.cri_key = ii->ii_enckey; /* XXX Rounds ? */ } if (tdbp->tdb_authalgxform) { /* Save the raw keys */ tdbp->tdb_amxkeylen = ii->ii_authkeylen; MALLOC(tdbp->tdb_amxkey, u_int8_t *, tdbp->tdb_amxkeylen, M_XDATA, M_WAITOK); bcopy(ii->ii_authkey, tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); bzero(&cria, sizeof(cria)); cria.cri_alg = tdbp->tdb_authalgxform->type; cria.cri_next = NULL; cria.cri_klen = ii->ii_authkeylen * 8; cria.cri_key = ii->ii_authkey; } return crypto_newsession(&tdbp->tdb_cryptoid, (tdbp->tdb_encalgxform ? &crie : &cria)); } /* * Paranoia. */ int esp_zeroize(struct tdb *tdbp) { int err; if (tdbp->tdb_amxkey) { bzero(tdbp->tdb_amxkey, tdbp->tdb_amxkeylen); FREE(tdbp->tdb_amxkey, M_XDATA); tdbp->tdb_amxkey = NULL; } if (tdbp->tdb_emxkey) { bzero(tdbp->tdb_emxkey, tdbp->tdb_emxkeylen); FREE(tdbp->tdb_emxkey, M_XDATA); tdbp->tdb_emxkey = NULL; } err = crypto_freesession(tdbp->tdb_cryptoid); tdbp->tdb_cryptoid = 0; return err; } #define MAXBUFSIZ (AH_ALEN_MAX > ESP_MAX_IVS ? AH_ALEN_MAX : ESP_MAX_IVS) /* * ESP input processing, called (eventually) through the protocol switch. */ int esp_input(struct mbuf *m, struct tdb *tdb, int skip, int protoff) { struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform; struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform; struct tdb_crypto *tc; int plen, alen, hlen; u_int32_t btsx; struct cryptodesc *crde = NULL, *crda = NULL; struct cryptop *crp; /* Determine the ESP header length */ if (tdb->tdb_flags & TDBF_NOREPLAY) hlen = sizeof(u_int32_t) + tdb->tdb_ivlen; /* "old" ESP */ else hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */ if (esph) alen = AH_HMAC_HASHLEN; else alen = 0; if (espx) { /* * Verify payload length is multiple of encryption algorithm * block size. */ plen = m->m_pkthdr.len - (skip + hlen + alen); if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { DPRINTF(("esp_input(): payload of %d octets not a multiple of %d octets, SA %s/%08x\n", plen, espx->blocksize, ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return EINVAL; } } /* Replay window checking, if appropriate */ if ((tdb->tdb_wnd > 0) && (!(tdb->tdb_flags & TDBF_NOREPLAY))) { m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t), (unsigned char *) &btsx); btsx = ntohl(btsx); switch (checkreplaywindow32(btsx, 0, &(tdb->tdb_rpl), tdb->tdb_wnd, &(tdb->tdb_bitmap))) { case 0: /* All's well */ break; case 1: DPRINTF(("esp_input(): replay counter wrapped for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_wrap++; m_freem(m); return EACCES; case 2: case 3: DPRINTF(("esp_input(): duplicate packet received in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_replay++; m_freem(m); return EACCES; default: DPRINTF(("esp_input(): bogus value from checkreplaywindow32() in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_replay++; m_freem(m); return EACCES; } } /* Update the counters */ tdb->tdb_cur_bytes += m->m_pkthdr.len - skip - hlen - alen; espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - 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, TDBEXP_TIMEOUT); m_freem(m); return ENXIO; } /* Notify on soft 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 */ } /* Get crypto descriptors */ crp = crypto_getreq(esph && espx ? 2 : 1); if (crp == NULL) { m_freem(m); DPRINTF(("esp_input(): failed to acquire crypto descriptors\n")); espstat.esps_crypto++; return ENOBUFS; } /* Get IPsec-specific opaque pointer */ MALLOC(tc, struct tdb_crypto *, sizeof(struct tdb_crypto), M_XDATA, M_NOWAIT); if (tc == NULL) { m_freem(m); crypto_freereq(crp); DPRINTF(("esp_input(): failed to allocate tdb_crypto\n")); espstat.esps_crypto++; return ENOBUFS; } if (esph) { crda = crp->crp_desc; crde = crda->crd_next; /* Authentication descriptor */ crda->crd_skip = skip; crda->crd_len = m->m_pkthdr.len - (skip + alen); crda->crd_inject = m->m_pkthdr.len - alen; crda->crd_alg = esph->type; crda->crd_key = tdb->tdb_amxkey; crda->crd_klen = tdb->tdb_amxkeylen * 8; /* Keep a copy of the authenticator */ MALLOC(tc->tc_ptr, caddr_t, alen, M_XDATA, M_NOWAIT); if (tc->tc_ptr == 0) { FREE(tc, M_XDATA); m_freem(m); crypto_freereq(crp); DPRINTF(("esp_input(): failed to allocate auth array\n")); espstat.esps_crypto++; return ENOBUFS; } /* Copy the authenticator */ m_copydata(m, m->m_pkthdr.len - alen, alen, tc->tc_ptr); } else { crde = crp->crp_desc; tc->tc_ptr = 0; } /* Crypto operation descriptor */ crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ crp->crp_flags = CRYPTO_F_IMBUF; crp->crp_buf = (caddr_t) m; crp->crp_callback = (int (*) (struct cryptop *)) esp_input_cb; crp->crp_sid = tdb->tdb_cryptoid; crp->crp_opaque = (caddr_t) tc; /* These are passed as-is to the callback */ tc->tc_skip = skip; tc->tc_protoff = protoff; tc->tc_spi = tdb->tdb_spi; tc->tc_proto = tdb->tdb_sproto; bcopy(&tdb->tdb_dst, &tc->tc_dst, sizeof(union sockaddr_union)); /* Decryption descriptor */ if (espx) { crde->crd_skip = skip + hlen; crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); crde->crd_inject = skip + hlen - tdb->tdb_ivlen; if (tdb->tdb_flags & TDBF_HALFIV) { /* Copy half-IV from packet */ m_copydata(m, crde->crd_inject, tdb->tdb_ivlen, crde->crd_iv); /* Cook IV */ for (btsx = 0; btsx < tdb->tdb_ivlen; btsx++) crde->crd_iv[tdb->tdb_ivlen + btsx] = ~crde->crd_iv[btsx]; crde->crd_flags |= CRD_F_IV_EXPLICIT; } crde->crd_alg = espx->type; crde->crd_key = tdb->tdb_emxkey; crde->crd_klen = tdb->tdb_emxkeylen * 8; /* XXX Rounds ? */ } return crypto_dispatch(crp); } /* * ESP input callback, called directly by the crypto driver. */ int esp_input_cb(void *op) { u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN]; int hlen, roff, skip, protoff, error; struct mbuf *m1, *mo, *m; struct cryptodesc *crd; struct auth_hash *esph; struct enc_xform *espx; struct tdb_crypto *tc; struct cryptop *crp; struct tdb *tdb; caddr_t ptr = 0; int s, err = 0; crp = (struct cryptop *) op; crd = crp->crp_desc; tc = (struct tdb_crypto *) crp->crp_opaque; skip = tc->tc_skip; protoff = tc->tc_protoff; ptr = tc->tc_ptr; m = (struct mbuf *) crp->crp_buf; s = spltdb(); tdb = gettdb(tc->tc_spi, &tc->tc_dst, tc->tc_proto); FREE(tc, M_XDATA); if (tdb == NULL) { espstat.esps_notdb++; DPRINTF(("esp_input_cb(): TDB is expired while in crypto")); goto baddone; } esph = (struct auth_hash *) tdb->tdb_authalgxform; espx = (struct enc_xform *) tdb->tdb_encalgxform; /* Check for crypto errors */ if (crp->crp_etype) { /* Reset the session ID */ if (tdb->tdb_cryptoid != 0) tdb->tdb_cryptoid = crp->crp_sid; if (crp->crp_etype == EAGAIN) { splx(s); return crypto_dispatch(crp); } espstat.esps_noxform++; DPRINTF(("esp_input_cb(): crypto error %d\n", crp->crp_etype)); error = crp->crp_etype; goto baddone; } /* Shouldn't happen... */ if (!m) { espstat.esps_crypto++; DPRINTF(("esp_input_cb(): bogus returned buffer from crypto\n")); error = EINVAL; goto baddone; } /* If authentication was performed, check now */ if (esph) { /* Copy the authenticator from the packet */ m_copydata(m, m->m_pkthdr.len - esph->authsize, esph->authsize, aalg); /* Verify authenticator */ if (bcmp(ptr, aalg, esph->authsize)) { DPRINTF(("esp_input_cb(): authentication failed for packet in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); espstat.esps_badauth++; error = EACCES; goto baddone; } /* Remove trailing authenticator */ m_adj(m, -(esph->authsize)); /* We have to manually free this */ FREE(ptr, M_XDATA); } /* Release the crypto descriptors */ crypto_freereq(crp); /* Determine the ESP header length */ if (tdb->tdb_flags & TDBF_NOREPLAY) hlen = sizeof(u_int32_t) + tdb->tdb_ivlen; /* "old" ESP */ else hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; /* "new" ESP */ /* Find beginning of ESP header */ m1 = m_getptr(m, skip, &roff); if (m1 == NULL) { espstat.esps_hdrops++; splx(s); DPRINTF(("esp_input_cb(): bad mbuf chain, SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); return EINVAL; } /* Remove the ESP header and IV from the mbuf. */ if (roff == 0) { /* The ESP header was conveniently at the beginning of the mbuf */ m_adj(m1, hlen); if (!(m1->m_flags & M_PKTHDR)) m->m_pkthdr.len -= hlen; } else if (roff + hlen >= m1->m_len) { /* * Part or all of the ESP header is at the end of this mbuf, so * first let's remove the remainder of the ESP header from the * beginning of the remainder of the mbuf chain, if any. */ if (roff + hlen > m1->m_len) { /* Adjust the next mbuf by the remainder */ m_adj(m1->m_next, roff + hlen - m1->m_len); /* The second mbuf is guaranteed not to have a pkthdr... */ m->m_pkthdr.len -= (roff + hlen - m1->m_len); } /* Now, let's unlink the mbuf chain for a second...*/ mo = m1->m_next; m1->m_next = NULL; /* ...and trim the end of the first part of the chain...sick */ m_adj(m1, -(m1->m_len - roff)); if (!(m1->m_flags & M_PKTHDR)) m->m_pkthdr.len -= (m1->m_len - roff); /* Finally, let's relink */ m1->m_next = mo; } else { /* * The ESP header lies in the "middle" of the mbuf...do an * overlapping copy of the remainder of the mbuf over the ESP * header. */ bcopy(mtod(m1, u_char *) + roff + hlen, mtod(m1, u_char *) + roff, m1->m_len - (roff + hlen)); m1->m_len -= hlen; m->m_pkthdr.len -= hlen; } /* Save the last three bytes of decrypted data */ m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree); /* Verify pad length */ if (lastthree[1] + 2 > m->m_pkthdr.len - skip) { espstat.esps_badilen++; splx(s); DPRINTF(("esp_input_cb(): invalid padding length %d for packet in SA %s/%08x\n", lastthree[1], ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); return EINVAL; } /* Verify correct decryption by checking the last padding bytes */ if (!(tdb->tdb_flags & TDBF_RANDOMPADDING)) { if ((lastthree[1] != lastthree[0]) && (lastthree[1] != 0)) { espstat.esps_badenc++; splx(s); DPRINTF(("esp_input(): decryption failed for packet in SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); return EINVAL; } } /* Trim the mbuf chain to remove the trailing authenticator and padding */ m_adj(m, -(lastthree[1] + 2)); /* Restore the Next Protocol field */ m_copyback(m, protoff, sizeof(u_int8_t), lastthree + 2); /* Back to generic IPsec input processing */ err = ipsec_common_input_cb(m, tdb, skip, protoff); splx(s); return err; baddone: splx(s); if (m) m_freem(m); /* We have to manually free this */ if (ptr) FREE(ptr, M_XDATA); crypto_freereq(crp); return error; } /* * ESP output routine, called by ipsp_process_packet(). */ int esp_output(struct mbuf *m, struct tdb *tdb, struct mbuf **mp, int skip, int protoff) { struct enc_xform *espx = (struct enc_xform *) tdb->tdb_encalgxform; struct auth_hash *esph = (struct auth_hash *) tdb->tdb_authalgxform; int ilen, hlen, rlen, plen, padding, blks, alen; struct mbuf *mi, *mo = (struct mbuf *) NULL; struct tdb_crypto *tc; unsigned char *pad; u_int8_t prot; struct cryptodesc *crde = NULL, *crda = NULL; struct cryptop *crp; #if NBPFILTER > 0 { struct ifnet *ifn; struct enchdr hdr; struct mbuf m1; bzero (&hdr, sizeof(hdr)); hdr.af = tdb->tdb_dst.sa.sa_family; hdr.spi = tdb->tdb_spi; if (espx) hdr.flags |= M_CONF; if (esph) hdr.flags |= M_AUTH; m1.m_next = m; m1.m_len = ENC_HDRLEN; m1.m_data = (char *) &hdr; if (tdb->tdb_interface) ifn = (struct ifnet *) tdb->tdb_interface; else ifn = &(encif[0].sc_if); if (ifn->if_bpf) bpf_mtap(ifn->if_bpf, &m1); } #endif if (tdb->tdb_flags & TDBF_NOREPLAY) hlen = sizeof(u_int32_t) + tdb->tdb_ivlen; else hlen = 2 * sizeof(u_int32_t) + tdb->tdb_ivlen; rlen = m->m_pkthdr.len - skip; /* Raw payload length */ if (espx) blks = espx->blocksize; else blks = 4; /* If no encryption is used, we have to be 4-byte aligned */ padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; plen = rlen + padding; /* Padded payload length */ if (esph) alen = AH_HMAC_HASHLEN; else alen = 0; espstat.esps_output++; /* Check for replay counter wrap-around in automatic (not manual) keying */ if ((!(tdb->tdb_flags & TDBF_NOREPLAY)) && (tdb->tdb_rpl == 0) && (tdb->tdb_wnd > 0)) { DPRINTF(("esp_output(): SA %s/%08x should have expired\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_wrap++; return EACCES; } switch (tdb->tdb_dst.sa.sa_family) { #ifdef INET case AF_INET: /* Check for IP maximum packet size violations */ if (skip + hlen + rlen + padding + alen > IP_MAXPACKET) { DPRINTF(("esp_output(): packet in SA %s/%08x got too big\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_toobig++; return EMSGSIZE; } break; #endif /* INET */ #ifdef INET6 case AF_INET6: /* Check for IPv6 maximum packet size violations */ if (skip + hlen + rlen + padding + alen > IPV6_MAXPACKET) { DPRINTF(("esp_output(): packet in SA %s/%08x got too big\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_toobig++; return EMSGSIZE; } break; #endif /* INET6 */ default: DPRINTF(("esp_output(): unknown/unsupported protocol family %d, SA %s/%08x\n", tdb->tdb_dst.sa.sa_family, ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_nopf++; return EPFNOSUPPORT; } /* Update the counters */ tdb->tdb_cur_bytes += m->m_pkthdr.len - skip; espstat.esps_obytes += m->m_pkthdr.len - skip; /* Hard byte 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, TDBEXP_TIMEOUT); m_freem(m); return EINVAL; } /* Soft byte 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 */ } /* * 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); } /* Inject ESP header */ mo = m_inject(m, skip, hlen, M_DONTWAIT); if (mo == NULL) { DPRINTF(("esp_output(): failed to inject ESP header for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); m_freem(m); espstat.esps_wrap++; return ENOBUFS; } /* Initialize ESP header */ bcopy((caddr_t) &tdb->tdb_spi, mtod(mo, caddr_t), sizeof(u_int32_t)); if (!(tdb->tdb_flags & TDBF_NOREPLAY)) { u_int32_t replay = htonl(tdb->tdb_rpl++); bcopy((caddr_t) &replay, mtod(mo, caddr_t) + sizeof(u_int32_t), sizeof(u_int32_t)); } /* * Add padding -- better to do it ourselves than use the crypto engine, * although if/when we support compression, we'd have to do that. */ pad = (u_char *) m_pad(m, padding + alen); if (pad == NULL) { DPRINTF(("esp_output(): m_pad() failed for SA %s/%08x\n", ipsp_address(tdb->tdb_dst), ntohl(tdb->tdb_spi))); return ENOBUFS; } /* Self-describing padding ? */ if (!(tdb->tdb_flags & TDBF_RANDOMPADDING)) { for (ilen = 0; ilen < padding - 2; ilen++) pad[ilen] = ilen + 1; } else { get_random_bytes((void *) pad, padding - 2); /* Random padding */ } /* Fix padding length and Next Protocol in padding itself */ pad[padding - 2] = padding - 2; m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1); /* Fix Next Protocol in IPv4/IPv6 header */ prot = IPPROTO_ESP; m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot); /* Get crypto descriptors */ crp = crypto_getreq(esph && espx ? 2 : 1); if (crp == NULL) { m_freem(m); DPRINTF(("esp_output(): failed to acquire crypto descriptors\n")); espstat.esps_crypto++; return ENOBUFS; } if (espx) { crde = crp->crp_desc; crda = crde->crd_next; /* Encryption descriptor */ crde->crd_skip = skip + hlen; crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen); crde->crd_flags = CRD_F_ENCRYPT; crde->crd_inject = skip + hlen - tdb->tdb_ivlen; if (tdb->tdb_flags & TDBF_HALFIV) { /* Copy half-iv in the packet */ m_copyback(m, crde->crd_inject, tdb->tdb_ivlen, tdb->tdb_iv); /* Cook half-iv */ bcopy(tdb->tdb_iv, crde->crd_iv, tdb->tdb_ivlen); for (ilen = 0; ilen < tdb->tdb_ivlen; ilen++) crde->crd_iv[tdb->tdb_ivlen + ilen] = ~crde->crd_iv[ilen]; crde->crd_flags |= CRD_F_IV_PRESENT | CRD_F_IV_EXPLICIT; } /* Encryption operation */ crde->crd_alg = espx->type; crde->crd_key = tdb->tdb_emxkey; crde->crd_klen = tdb->tdb_emxkeylen * 8; /* XXX Rounds ? */ } else crda = crp->crp_desc; /* IPsec-specific opaque crypto info */ MALLOC(tc, struct tdb_crypto *, sizeof(struct tdb_crypto), M_XDATA, M_NOWAIT); if (tc == NULL) { m_freem(m); crypto_freereq(crp); DPRINTF(("esp_output(): failed to allocate tdb_crypto\n")); espstat.esps_crypto++; return ENOBUFS; } tc->tc_spi = tdb->tdb_spi; tc->tc_proto = tdb->tdb_sproto; tc->tc_ptr = 0; bcopy(&tdb->tdb_dst, &tc->tc_dst, sizeof(union sockaddr_union)); /* Crypto operation descriptor */ crp->crp_ilen = m->m_pkthdr.len; /* Total input length */ crp->crp_flags = CRYPTO_F_IMBUF; crp->crp_buf = (caddr_t) m; crp->crp_callback = (int (*) (struct cryptop *)) esp_output_cb; crp->crp_opaque = (caddr_t) tc; crp->crp_sid = tdb->tdb_cryptoid; if (esph) { /* Authentication descriptor */ crda->crd_skip = skip; crda->crd_len = m->m_pkthdr.len - (skip + alen); crda->crd_inject = m->m_pkthdr.len - alen; /* Authentication operation */ crda->crd_alg = esph->type; crda->crd_key = tdb->tdb_amxkey; crda->crd_klen = tdb->tdb_amxkeylen * 8; } return crypto_dispatch(crp); } /* * ESP output callback, called directly by the crypto driver. */ int esp_output_cb(void *op) { struct cryptop *crp = (struct cryptop *) op; struct tdb_crypto *tc; struct tdb *tdb; struct mbuf *m; int error, s; tc = (struct tdb_crypto *) crp->crp_opaque; m = (struct mbuf *) crp->crp_buf; s = spltdb(); tdb = gettdb(tc->tc_spi, &tc->tc_dst, tc->tc_proto); FREE(tc, M_XDATA); if (tdb == NULL) { espstat.esps_notdb++; DPRINTF(("esp_output_cb(): TDB is expired while in crypto\n")); goto baddone; } /* Check for crypto errors */ if (crp->crp_etype) { /* Reset session ID */ if (tdb->tdb_cryptoid != 0) tdb->tdb_cryptoid = crp->crp_sid; if (crp->crp_etype == EAGAIN) { splx(s); return crypto_dispatch(crp); } espstat.esps_noxform++; DPRINTF(("esp_output_cb(): crypto error %d\n", crp->crp_etype)); error = crp->crp_etype; goto baddone; } /* Shouldn't happen... */ if (!m) { espstat.esps_crypto++; DPRINTF(("esp_output_cb(): bogus returned buffer from crypto\n")); error = EINVAL; goto baddone; } /* Release crypto descriptors */ crypto_freereq(crp); /* * If we're doing half-iv, keep a copy of the last few bytes of the * encrypted part, for use as the next IV. Note that HALF-IV is only * supposed to be used without authentication (the old ESP specs). */ if (tdb->tdb_flags & TDBF_HALFIV) m_copydata(m, m->m_pkthdr.len - tdb->tdb_ivlen, tdb->tdb_ivlen, tdb->tdb_iv); /* Call the IPsec input callback */ error = ipsp_process_done(m, tdb); splx(s); return error; baddone: splx(s); if (m) m_freem(m); crypto_freereq(crp); return error; } /* * 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; } /* * m_pad(m, n) pads with bytes at the end. The packet header * length is updated, and a pointer to the first byte of the padding * (which is guaranteed to be all in one mbuf) is returned. */ caddr_t m_pad(struct mbuf *m, int n) { register struct mbuf *m0, *m1; register int len, pad; caddr_t retval; if (n <= 0) /* no stupid arguments */ { DPRINTF(("m_pad(): pad length invalid (%d)\n", n)); return NULL; } len = m->m_pkthdr.len; pad = n; m0 = m; while (m0->m_len < len) { len -= m0->m_len; m0 = m0->m_next; } if (m0->m_len != len) { DPRINTF(("m_pad(): length mismatch (should be %d instead of %d)\n", m->m_pkthdr.len, m->m_pkthdr.len + m0->m_len - len)); m_freem(m); return NULL; } if ((m0->m_flags & M_EXT) || (m0->m_data + m0->m_len + pad >= &(m0->m_dat[MLEN]))) { /* * Add an mbuf to the chain */ MGET(m1, M_DONTWAIT, MT_DATA); if (m1 == 0) { m_freem(m0); DPRINTF(("m_pad(): cannot append\n")); return NULL; } m0->m_next = m1; m0 = m1; m0->m_len = 0; } retval = m0->m_data + m0->m_len; m0->m_len += pad; m->m_pkthdr.len += pad; return retval; }