/* $FreeBSD$ */ /* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 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. * Copyright (c) 2001 Angelos D. Keromytis. * * Permission to use, copy, and modify this software with or 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 "opt_inet.h" #include "opt_inet6.h" #include "opt_ipsec.h" #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 INET6 #include #include #include #endif #include #include #include #include #define SPI_SIZE 4 VNET_DEFINE(int, esp_enable) = 1; VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1; #define V_esp_ctr_compatibility VNET(esp_ctr_compatibility) VNET_PCPUSTAT_DEFINE(struct espstat, espstat); VNET_PCPUSTAT_SYSINIT(espstat); #ifdef VIMAGE VNET_PCPUSTAT_SYSUNINIT(espstat); #endif /* VIMAGE */ SYSCTL_DECL(_net_inet_esp); SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, ""); SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0, "Align AES-CTR encrypted transmitted frames to blocksize"); SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats, struct espstat, espstat, "ESP statistics (struct espstat, netipsec/esp_var.h"); static int esp_input_cb(struct cryptop *op); static int esp_output_cb(struct cryptop *crp); size_t esp_hdrsiz(struct secasvar *sav) { size_t size; if (sav != NULL) { /*XXX not right for null algorithm--does it matter??*/ IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("SA with null xform")); if (sav->flags & SADB_X_EXT_OLD) size = sizeof (struct esp); else size = sizeof (struct newesp); size += sav->tdb_encalgxform->blocksize + 9; /*XXX need alg check???*/ if (sav->tdb_authalgxform != NULL && sav->replay) size += ah_hdrsiz(sav); } else { /* * base header size * + max iv length for CBC mode * + max pad length * + sizeof (pad length field) * + sizeof (next header field) * + max icv supported. */ size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16; } return size; } /* * esp_init() is called when an SPI is being set up. */ static int esp_init(struct secasvar *sav, struct xformsw *xsp) { const struct enc_xform *txform; struct crypto_session_params csp; int keylen; int error; txform = enc_algorithm_lookup(sav->alg_enc); if (txform == NULL) { DPRINTF(("%s: unsupported encryption algorithm %d\n", __func__, sav->alg_enc)); return EINVAL; } if (sav->key_enc == NULL) { DPRINTF(("%s: no encoding key for %s algorithm\n", __func__, txform->name)); return EINVAL; } if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) { DPRINTF(("%s: 4-byte IV not supported with protocol\n", __func__)); return EINVAL; } /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */ keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4; if (txform->minkey > keylen || keylen > txform->maxkey) { DPRINTF(("%s: invalid key length %u, must be in the range " "[%u..%u] for algorithm %s\n", __func__, keylen, txform->minkey, txform->maxkey, txform->name)); return EINVAL; } if (SAV_ISCTRORGCM(sav)) sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */ else sav->ivlen = txform->ivsize; memset(&csp, 0, sizeof(csp)); /* * Setup AH-related state. */ if (sav->alg_auth != 0) { error = ah_init0(sav, xsp, &csp); if (error) return error; } /* NB: override anything set in ah_init0 */ sav->tdb_xform = xsp; sav->tdb_encalgxform = txform; /* * Whenever AES-GCM is used for encryption, one * of the AES authentication algorithms is chosen * as well, based on the key size. */ if (sav->alg_enc == SADB_X_EALG_AESGCM16) { switch (keylen) { case AES_128_GMAC_KEY_LEN: sav->alg_auth = SADB_X_AALG_AES128GMAC; sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128; break; case AES_192_GMAC_KEY_LEN: sav->alg_auth = SADB_X_AALG_AES192GMAC; sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192; break; case AES_256_GMAC_KEY_LEN: sav->alg_auth = SADB_X_AALG_AES256GMAC; sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256; break; default: DPRINTF(("%s: invalid key length %u" "for algorithm %s\n", __func__, keylen, txform->name)); return EINVAL; } csp.csp_mode = CSP_MODE_AEAD; if (sav->flags & SADB_X_SAFLAGS_ESN) csp.csp_flags |= CSP_F_SEPARATE_AAD; } else if (sav->alg_auth != 0) { csp.csp_mode = CSP_MODE_ETA; if (sav->flags & SADB_X_SAFLAGS_ESN) csp.csp_flags |= CSP_F_ESN; } else csp.csp_mode = CSP_MODE_CIPHER; /* Initialize crypto session. */ csp.csp_cipher_alg = sav->tdb_encalgxform->type; if (csp.csp_cipher_alg != CRYPTO_NULL_CBC) { csp.csp_cipher_key = sav->key_enc->key_data; csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 - SAV_ISCTRORGCM(sav) * 4; }; csp.csp_ivlen = txform->ivsize; error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); return error; } static void esp_cleanup(struct secasvar *sav) { crypto_freesession(sav->tdb_cryptoid); sav->tdb_cryptoid = NULL; sav->tdb_authalgxform = NULL; sav->tdb_encalgxform = NULL; } /* * ESP input processing, called (eventually) through the protocol switch. */ static int esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) { IPSEC_DEBUG_DECLARE(char buf[128]); const struct auth_hash *esph; const struct enc_xform *espx; struct xform_data *xd; struct cryptop *crp; struct newesp *esp; uint8_t *ivp; crypto_session_t cryptoid; int alen, error, hlen, plen; uint32_t seqh; const struct crypto_session_params *csp; IPSEC_ASSERT(sav != NULL, ("null SA")); IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform")); error = EINVAL; /* Valid IP Packet length ? */ if ( (skip&3) || (m->m_pkthdr.len&3) ){ DPRINTF(("%s: misaligned packet, skip %u pkt len %u", __func__, skip, m->m_pkthdr.len)); ESPSTAT_INC(esps_badilen); goto bad; } if (m->m_len < skip + sizeof(*esp)) { m = m_pullup(m, skip + sizeof(*esp)); if (m == NULL) { DPRINTF(("%s: cannot pullup header\n", __func__)); ESPSTAT_INC(esps_hdrops); /*XXX*/ error = ENOBUFS; goto bad; } } esp = (struct newesp *)(mtod(m, caddr_t) + skip); esph = sav->tdb_authalgxform; espx = sav->tdb_encalgxform; /* Determine the ESP header and auth length */ if (sav->flags & SADB_X_EXT_OLD) hlen = sizeof (struct esp) + sav->ivlen; else hlen = sizeof (struct newesp) + sav->ivlen; alen = xform_ah_authsize(esph); /* * Verify payload length is multiple of encryption algorithm * block size. * * NB: This works for the null algorithm because the blocksize * is 4 and all packets must be 4-byte aligned regardless * of the algorithm. */ plen = m->m_pkthdr.len - (skip + hlen + alen); if ((plen & (espx->blocksize - 1)) || (plen <= 0)) { DPRINTF(("%s: payload of %d octets not a multiple of %d octets," " SA %s/%08lx\n", __func__, plen, espx->blocksize, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long)ntohl(sav->spi))); ESPSTAT_INC(esps_badilen); goto bad; } /* * Check sequence number. */ SECASVAR_LOCK(sav); if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) { if (ipsec_chkreplay(ntohl(esp->esp_seq), &seqh, sav) == 0) { SECASVAR_UNLOCK(sav); DPRINTF(("%s: packet replay check for %s\n", __func__, ipsec_sa2str(sav, buf, sizeof(buf)))); ESPSTAT_INC(esps_replay); error = EACCES; goto bad; } seqh = htonl(seqh); } cryptoid = sav->tdb_cryptoid; SECASVAR_UNLOCK(sav); /* Update the counters */ ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen)); /* Get crypto descriptors */ crp = crypto_getreq(cryptoid, M_NOWAIT); if (crp == NULL) { DPRINTF(("%s: failed to acquire crypto descriptors\n", __func__)); ESPSTAT_INC(esps_crypto); error = ENOBUFS; goto bad; } /* Get IPsec-specific opaque pointer */ xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO); if (xd == NULL) { DPRINTF(("%s: failed to allocate xform_data\n", __func__)); goto xd_fail; } if (esph != NULL) { crp->crp_op = CRYPTO_OP_VERIFY_DIGEST; if (SAV_ISGCM(sav)) crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ else crp->crp_aad_length = hlen; csp = crypto_get_params(crp->crp_session); if ((csp->csp_flags & CSP_F_SEPARATE_AAD) && (sav->replay != NULL) && (sav->replay->wsize != 0)) { int aad_skip; crp->crp_aad_length += sizeof(seqh); crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT); if (crp->crp_aad == NULL) { DPRINTF(("%s: failed to allocate xform_data\n", __func__)); goto crp_aad_fail; } /* SPI */ m_copydata(m, skip, SPI_SIZE, crp->crp_aad); aad_skip = SPI_SIZE; /* ESN */ bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh)); aad_skip += sizeof(seqh); /* Rest of aad */ if (crp->crp_aad_length - aad_skip > 0) m_copydata(m, skip + SPI_SIZE, crp->crp_aad_length - aad_skip, (char *)crp->crp_aad + aad_skip); } else crp->crp_aad_start = skip; if (csp->csp_flags & CSP_F_ESN && sav->replay != NULL && sav->replay->wsize != 0) memcpy(crp->crp_esn, &seqh, sizeof(seqh)); crp->crp_digest_start = m->m_pkthdr.len - alen; } /* Crypto operation descriptor */ crp->crp_flags = CRYPTO_F_CBIFSYNC; crypto_use_mbuf(crp, m); crp->crp_callback = esp_input_cb; crp->crp_opaque = xd; /* These are passed as-is to the callback */ xd->sav = sav; xd->protoff = protoff; xd->skip = skip; xd->cryptoid = cryptoid; xd->vnet = curvnet; /* Decryption descriptor */ crp->crp_op |= CRYPTO_OP_DECRYPT; crp->crp_payload_start = skip + hlen; crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); /* Generate or read cipher IV. */ if (SAV_ISCTRORGCM(sav)) { ivp = &crp->crp_iv[0]; /* * AES-GCM and AES-CTR use similar cipher IV formats * defined in RFC 4106 section 4 and RFC 3686 section * 4, respectively. * * The first 4 bytes of the cipher IV contain an * implicit salt, or nonce, obtained from the last 4 * bytes of the encryption key. The next 8 bytes hold * an explicit IV unique to each packet. This * explicit IV is used as the ESP IV for the packet. * The last 4 bytes hold a big-endian block counter * incremented for each block. For AES-GCM, the block * counter's initial value is defined as part of the * algorithm. For AES-CTR, the block counter's * initial value for each packet is defined as 1 by * RFC 3686. * * ------------------------------------------ * | Salt | Explicit ESP IV | Block Counter | * ------------------------------------------ * 4 bytes 8 bytes 4 bytes */ memcpy(ivp, sav->key_enc->key_data + _KEYLEN(sav->key_enc) - 4, 4); m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); if (SAV_ISCTR(sav)) { be32enc(&ivp[sav->ivlen + 4], 1); } crp->crp_flags |= CRYPTO_F_IV_SEPARATE; } else if (sav->ivlen != 0) crp->crp_iv_start = skip + hlen - sav->ivlen; if (V_async_crypto) return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); else return (crypto_dispatch(crp)); crp_aad_fail: free(xd, M_XDATA); xd_fail: crypto_freereq(crp); ESPSTAT_INC(esps_crypto); error = ENOBUFS; bad: m_freem(m); key_freesav(&sav); return (error); } /* * ESP input callback from the crypto driver. */ static int esp_input_cb(struct cryptop *crp) { IPSEC_DEBUG_DECLARE(char buf[128]); uint8_t lastthree[3]; const struct auth_hash *esph; struct mbuf *m; struct xform_data *xd; struct secasvar *sav; struct secasindex *saidx; crypto_session_t cryptoid; int hlen, skip, protoff, error, alen; m = crp->crp_buf.cb_mbuf; xd = crp->crp_opaque; CURVNET_SET(xd->vnet); sav = xd->sav; skip = xd->skip; protoff = xd->protoff; cryptoid = xd->cryptoid; saidx = &sav->sah->saidx; esph = sav->tdb_authalgxform; /* Check for crypto errors */ if (crp->crp_etype) { if (crp->crp_etype == EAGAIN) { /* Reset the session ID */ if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) crypto_freesession(cryptoid); xd->cryptoid = crp->crp_session; CURVNET_RESTORE(); return (crypto_dispatch(crp)); } /* EBADMSG indicates authentication failure. */ if (!(crp->crp_etype == EBADMSG && esph != NULL)) { ESPSTAT_INC(esps_noxform); DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); error = crp->crp_etype; goto bad; } } /* Shouldn't happen... */ if (m == NULL) { ESPSTAT_INC(esps_crypto); DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); error = EINVAL; goto bad; } ESPSTAT_INC(esps_hist[sav->alg_enc]); /* If authentication was performed, check now. */ if (esph != NULL) { alen = xform_ah_authsize(esph); AHSTAT_INC(ahs_hist[sav->alg_auth]); if (crp->crp_etype == EBADMSG) { DPRINTF(("%s: authentication hash mismatch for " "packet in SA %s/%08lx\n", __func__, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); ESPSTAT_INC(esps_badauth); error = EACCES; goto bad; } m->m_flags |= M_AUTHIPDGM; /* Remove trailing authenticator */ m_adj(m, -alen); } /* Release the crypto descriptors */ free(xd, M_XDATA), xd = NULL; free(crp->crp_aad, M_XDATA), crp->crp_aad = NULL; crypto_freereq(crp), crp = NULL; /* * Packet is now decrypted. */ m->m_flags |= M_DECRYPTED; /* * Update replay sequence number, if appropriate. */ if (sav->replay) { u_int32_t seq; m_copydata(m, skip + offsetof(struct newesp, esp_seq), sizeof (seq), (caddr_t) &seq); SECASVAR_LOCK(sav); if (ipsec_updatereplay(ntohl(seq), sav)) { SECASVAR_UNLOCK(sav); DPRINTF(("%s: packet replay check for %s\n", __func__, ipsec_sa2str(sav, buf, sizeof(buf)))); ESPSTAT_INC(esps_replay); error = EACCES; goto bad; } SECASVAR_UNLOCK(sav); } /* Determine the ESP header length */ if (sav->flags & SADB_X_EXT_OLD) hlen = sizeof (struct esp) + sav->ivlen; else hlen = sizeof (struct newesp) + sav->ivlen; /* Remove the ESP header and IV from the mbuf. */ error = m_striphdr(m, skip, hlen); if (error) { ESPSTAT_INC(esps_hdrops); DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); goto bad; } /* 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_INC(esps_badilen); DPRINTF(("%s: invalid padding length %d for %u byte packet " "in SA %s/%08lx\n", __func__, lastthree[1], m->m_pkthdr.len - skip, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); error = EINVAL; goto bad; } /* Verify correct decryption by checking the last padding bytes */ if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) { if (lastthree[1] != lastthree[0] && lastthree[1] != 0) { ESPSTAT_INC(esps_badenc); DPRINTF(("%s: decryption failed for packet in " "SA %s/%08lx\n", __func__, ipsec_address( &sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); error = EINVAL; goto bad; } } /* * RFC4303 2.6: * Silently drop packet if next header field is IPPROTO_NONE. */ if (lastthree[2] == IPPROTO_NONE) goto bad; /* Trim the mbuf chain to remove 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); switch (saidx->dst.sa.sa_family) { #ifdef INET6 case AF_INET6: error = ipsec6_common_input_cb(m, sav, skip, protoff); break; #endif #ifdef INET case AF_INET: error = ipsec4_common_input_cb(m, sav, skip, protoff); break; #endif default: panic("%s: Unexpected address family: %d saidx=%p", __func__, saidx->dst.sa.sa_family, saidx); } CURVNET_RESTORE(); return error; bad: CURVNET_RESTORE(); if (sav != NULL) key_freesav(&sav); if (m != NULL) m_freem(m); if (xd != NULL) free(xd, M_XDATA); if (crp != NULL) { free(crp->crp_aad, M_XDATA); crypto_freereq(crp); } return error; } /* * ESP output routine, called by ipsec[46]_perform_request(). */ static int esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, u_int idx, int skip, int protoff) { IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); struct cryptop *crp; const struct auth_hash *esph; const struct enc_xform *espx; struct mbuf *mo = NULL; struct xform_data *xd; struct secasindex *saidx; unsigned char *pad; uint8_t *ivp; uint64_t cntr; crypto_session_t cryptoid; int hlen, rlen, padding, blks, alen, i, roff; int error, maxpacketsize; uint8_t prot; uint32_t seqh; const struct crypto_session_params *csp; IPSEC_ASSERT(sav != NULL, ("null SA")); esph = sav->tdb_authalgxform; espx = sav->tdb_encalgxform; IPSEC_ASSERT(espx != NULL, ("null encoding xform")); if (sav->flags & SADB_X_EXT_OLD) hlen = sizeof (struct esp) + sav->ivlen; else hlen = sizeof (struct newesp) + sav->ivlen; rlen = m->m_pkthdr.len - skip; /* Raw payload length. */ /* * RFC4303 2.4 Requires 4 byte alignment. * Old versions of FreeBSD can't decrypt partial blocks encrypted * with AES-CTR. Align payload to native_blocksize (16 bytes) * in order to preserve compatibility. */ if (SAV_ISCTR(sav) && V_esp_ctr_compatibility) blks = MAX(4, espx->native_blocksize); /* Cipher blocksize */ else blks = MAX(4, espx->blocksize); /* XXX clamp padding length a la KAME??? */ padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; alen = xform_ah_authsize(esph); ESPSTAT_INC(esps_output); saidx = &sav->sah->saidx; /* Check for maximum packet size violations. */ switch (saidx->dst.sa.sa_family) { #ifdef INET case AF_INET: maxpacketsize = IP_MAXPACKET; break; #endif /* INET */ #ifdef INET6 case AF_INET6: maxpacketsize = IPV6_MAXPACKET; break; #endif /* INET6 */ default: DPRINTF(("%s: unknown/unsupported protocol " "family %d, SA %s/%08lx\n", __func__, saidx->dst.sa.sa_family, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); ESPSTAT_INC(esps_nopf); error = EPFNOSUPPORT; goto bad; } /* DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n", __func__, skip, hlen, rlen, padding, alen, blks)); */ if (skip + hlen + rlen + padding + alen > maxpacketsize) { DPRINTF(("%s: packet in SA %s/%08lx got too big " "(len %u, max len %u)\n", __func__, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi), skip + hlen + rlen + padding + alen, maxpacketsize)); ESPSTAT_INC(esps_toobig); error = EMSGSIZE; goto bad; } /* Update the counters. */ ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip); m = m_unshare(m, M_NOWAIT); if (m == NULL) { DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); ESPSTAT_INC(esps_hdrops); error = ENOBUFS; goto bad; } /* Inject ESP header. */ mo = m_makespace(m, skip, hlen, &roff); if (mo == NULL) { DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n", __func__, hlen, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */ error = ENOBUFS; goto bad; } /* Initialize ESP header. */ bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(uint32_t)); SECASVAR_LOCK(sav); if (sav->replay) { uint32_t replay; #ifdef REGRESSION /* Emulate replay attack when ipsec_replay is TRUE. */ if (!V_ipsec_replay) #endif sav->replay->count++; replay = htonl((uint32_t)sav->replay->count); bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff + sizeof(uint32_t), sizeof(uint32_t)); seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); } cryptoid = sav->tdb_cryptoid; if (SAV_ISCTRORGCM(sav)) cntr = sav->cntr++; SECASVAR_UNLOCK(sav); /* * 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(("%s: m_pad failed for SA %s/%08lx\n", __func__, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); m = NULL; /* NB: free'd by m_pad */ error = ENOBUFS; goto bad; } /* * Add padding: random, zero, or self-describing. * XXX catch unexpected setting */ switch (sav->flags & SADB_X_EXT_PMASK) { case SADB_X_EXT_PRAND: arc4random_buf(pad, padding - 2); break; case SADB_X_EXT_PZERO: bzero(pad, padding - 2); break; case SADB_X_EXT_PSEQ: for (i = 0; i < padding - 2; i++) pad[i] = i+1; break; } /* 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 descriptor. */ crp = crypto_getreq(cryptoid, M_NOWAIT); if (crp == NULL) { DPRINTF(("%s: failed to acquire crypto descriptor\n", __func__)); ESPSTAT_INC(esps_crypto); error = ENOBUFS; goto bad; } /* IPsec-specific opaque crypto info. */ xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO); if (xd == NULL) { DPRINTF(("%s: failed to allocate xform_data\n", __func__)); goto xd_fail; } /* Encryption descriptor. */ crp->crp_payload_start = skip + hlen; crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen); crp->crp_op = CRYPTO_OP_ENCRYPT; /* Generate cipher and ESP IVs. */ ivp = &crp->crp_iv[0]; if (SAV_ISCTRORGCM(sav)) { /* * See comment in esp_input() for details on the * cipher IV. A simple per-SA counter stored in * 'cntr' is used as the explicit ESP IV. */ memcpy(ivp, sav->key_enc->key_data + _KEYLEN(sav->key_enc) - 4, 4); be64enc(&ivp[4], cntr); if (SAV_ISCTR(sav)) { be32enc(&ivp[sav->ivlen + 4], 1); } m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]); crp->crp_flags |= CRYPTO_F_IV_SEPARATE; } else if (sav->ivlen != 0) { arc4rand(ivp, sav->ivlen, 0); crp->crp_iv_start = skip + hlen - sav->ivlen; m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp); } /* Callback parameters */ xd->sp = sp; xd->sav = sav; xd->idx = idx; xd->cryptoid = cryptoid; xd->vnet = curvnet; /* Crypto operation descriptor. */ crp->crp_flags |= CRYPTO_F_CBIFSYNC; crypto_use_mbuf(crp, m); crp->crp_callback = esp_output_cb; crp->crp_opaque = xd; if (esph) { /* Authentication descriptor. */ crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST; if (SAV_ISGCM(sav)) crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */ else crp->crp_aad_length = hlen; csp = crypto_get_params(crp->crp_session); if (csp->csp_flags & CSP_F_SEPARATE_AAD && sav->replay != NULL) { int aad_skip; crp->crp_aad_length += sizeof(seqh); crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT); if (crp->crp_aad == NULL) { DPRINTF(("%s: failed to allocate xform_data\n", __func__)); goto crp_aad_fail; } /* SPI */ m_copydata(m, skip, SPI_SIZE, crp->crp_aad); aad_skip = SPI_SIZE; /* ESN */ bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh)); aad_skip += sizeof(seqh); /* Rest of aad */ if (crp->crp_aad_length - aad_skip > 0) m_copydata(m, skip + SPI_SIZE, crp->crp_aad_length - aad_skip, (char *)crp->crp_aad + aad_skip); } else crp->crp_aad_start = skip; if (csp->csp_flags & CSP_F_ESN && sav->replay != NULL) memcpy(crp->crp_esn, &seqh, sizeof(seqh)); crp->crp_digest_start = m->m_pkthdr.len - alen; } if (V_async_crypto) return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); else return (crypto_dispatch(crp)); crp_aad_fail: free(xd, M_XDATA); xd_fail: crypto_freereq(crp); ESPSTAT_INC(esps_crypto); error = ENOBUFS; bad: if (m) m_freem(m); key_freesav(&sav); key_freesp(&sp); return (error); } /* * ESP output callback from the crypto driver. */ static int esp_output_cb(struct cryptop *crp) { struct xform_data *xd; struct secpolicy *sp; struct secasvar *sav; struct mbuf *m; crypto_session_t cryptoid; u_int idx; int error; xd = (struct xform_data *) crp->crp_opaque; CURVNET_SET(xd->vnet); m = crp->crp_buf.cb_mbuf; sp = xd->sp; sav = xd->sav; idx = xd->idx; cryptoid = xd->cryptoid; /* Check for crypto errors. */ if (crp->crp_etype) { if (crp->crp_etype == EAGAIN) { /* Reset the session ID */ if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) crypto_freesession(cryptoid); xd->cryptoid = crp->crp_session; CURVNET_RESTORE(); return (crypto_dispatch(crp)); } ESPSTAT_INC(esps_noxform); DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); error = crp->crp_etype; m_freem(m); goto bad; } /* Shouldn't happen... */ if (m == NULL) { ESPSTAT_INC(esps_crypto); DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); error = EINVAL; goto bad; } free(xd, M_XDATA); free(crp->crp_aad, M_XDATA); crypto_freereq(crp); ESPSTAT_INC(esps_hist[sav->alg_enc]); if (sav->tdb_authalgxform != NULL) AHSTAT_INC(ahs_hist[sav->alg_auth]); #ifdef REGRESSION /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ if (V_ipsec_integrity) { static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN]; const struct auth_hash *esph; /* * Corrupt HMAC if we want to test integrity verification of * the other side. */ esph = sav->tdb_authalgxform; if (esph != NULL) { int alen; alen = xform_ah_authsize(esph); m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); } } #endif /* NB: m is reclaimed by ipsec_process_done. */ error = ipsec_process_done(m, sp, sav, idx); CURVNET_RESTORE(); return (error); bad: CURVNET_RESTORE(); free(xd, M_XDATA); free(crp->crp_aad, M_XDATA); crypto_freereq(crp); key_freesav(&sav); key_freesp(&sp); return (error); } static struct xformsw esp_xformsw = { .xf_type = XF_ESP, .xf_name = "IPsec ESP", .xf_init = esp_init, .xf_cleanup = esp_cleanup, .xf_input = esp_input, .xf_output = esp_output, }; SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, xform_attach, &esp_xformsw); SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, xform_detach, &esp_xformsw);