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- /* $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 <sys/param.h>
- #include <sys/systm.h>
- #include <sys/malloc.h>
- #include <sys/mbuf.h>
- #include <sys/socket.h>
- #include <sys/syslog.h>
- #include <sys/kernel.h>
- #include <sys/lock.h>
- #include <sys/random.h>
- #include <sys/mutex.h>
- #include <sys/sysctl.h>
- #include <sys/mutex.h>
- #include <machine/atomic.h>
- #include <net/if.h>
- #include <net/vnet.h>
- #include <netinet/in.h>
- #include <netinet/in_systm.h>
- #include <netinet/ip.h>
- #include <netinet/ip_ecn.h>
- #include <netinet/ip6.h>
- #include <netipsec/ipsec.h>
- #include <netipsec/ah.h>
- #include <netipsec/ah_var.h>
- #include <netipsec/esp.h>
- #include <netipsec/esp_var.h>
- #include <netipsec/xform.h>
- #ifdef INET6
- #include <netinet6/ip6_var.h>
- #include <netipsec/ipsec6.h>
- #include <netinet6/ip6_ecn.h>
- #endif
- #include <netipsec/key.h>
- #include <netipsec/key_debug.h>
- #include <opencrypto/cryptodev.h>
- #include <opencrypto/xform.h>
- #define SPI_SIZE 4
- VNET_DEFINE(int, esp_enable) = 1;
- VNET_DEFINE(int, esp_ctr_compatibility) = 1;
- 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 MALLOC_DEFINE(M_ESP, "esp", "IPsec ESP");
- 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 -
- SAV_ISCHACHA(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_ISCHACHA(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_enc == SADB_X_EALG_CHACHA20POLY1305) {
- sav->alg_auth = SADB_X_AALG_CHACHA20POLY1305;
- sav->tdb_authalgxform = &auth_hash_poly1305;
- 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 - SAV_ISCHACHA(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;
- SECASVAR_RLOCK_TRACKER;
- 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_RLOCK(sav);
- if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
- if (ipsec_chkreplay(ntohl(esp->esp_seq), &seqh, sav) == 0) {
- SECASVAR_RUNLOCK(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_RUNLOCK(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_ESP, 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) || SAV_ISCHACHA(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_ESP, 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) || SAV_ISCHACHA(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_ESP);
- 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;
- SECASVAR_RLOCK_TRACKER;
- m = crp->crp_buf.cb_mbuf;
- xd = crp->crp_opaque;
- CURVNET_SET(xd->vnet);
- sav = xd->sav;
- if (sav->state >= SADB_SASTATE_DEAD) {
- /* saidx is freed */
- DPRINTF(("%s: dead SA %p spi %#x\n", __func__, sav, sav->spi));
- ESPSTAT_INC(esps_notdb);
- error = ESRCH;
- goto bad;
- }
- 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_ESP), xd = NULL;
- free(crp->crp_aad, M_ESP), 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_RLOCK(sav);
- if (ipsec_updatereplay(ntohl(seq), sav)) {
- SECASVAR_RUNLOCK(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_RUNLOCK(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:
- if (sav != NULL)
- key_freesav(&sav);
- if (m != NULL)
- m_freem(m);
- if (xd != NULL)
- free(xd, M_ESP);
- if (crp != NULL) {
- free(crp->crp_aad, M_ESP);
- crypto_freereq(crp);
- }
- CURVNET_RESTORE();
- 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;
- SECASVAR_RLOCK_TRACKER;
- 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_RLOCK(sav);
- if (sav->replay) {
- uint32_t replay;
- SECREPLAY_LOCK(sav->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));
- SECREPLAY_UNLOCK(sav->replay);
- }
- cryptoid = sav->tdb_cryptoid;
- if (SAV_ISCTRORGCM(sav) || SAV_ISCHACHA(sav))
- cntr = sav->cntr++;
- SECASVAR_RUNLOCK(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_ESP, 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) || SAV_ISCHACHA(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) || SAV_ISCHACHA(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_ESP, 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_ESP);
- 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_ESP);
- free(crp->crp_aad, M_ESP);
- 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:
- free(xd, M_ESP);
- free(crp->crp_aad, M_ESP);
- crypto_freereq(crp);
- key_freesav(&sav);
- key_freesp(&sp);
- CURVNET_RESTORE();
- 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);
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