As RFC 4304 describes there is anti-replay algorithm responsibility to provide appropriate value of Extended Sequence Number. This patch introduces anti-replay algorithm with ESN support based on RFC 4304, however to avoid performance regressions window implementation was based on RFC 6479, which was already implemented in FreeBSD. To keep things clean and improve code readability, implementation of window is kept in seperate functions. Submitted by: Grzegorz Jaszczyk <jaz@semihalf.com> Patryk Duda <pdk@semihalf.com> Reviewed by: jhb Differential revision: https://reviews.freebsd.org/D22367 Obtained from: Semihalf Sponsored by: Stormshield
973 lines
26 KiB
C
973 lines
26 KiB
C
/* $FreeBSD$ */
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/* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
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/*-
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* The authors of this code are John Ioannidis (ji@tla.org),
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* Angelos D. Keromytis (kermit@csd.uch.gr) and
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* Niels Provos (provos@physnet.uni-hamburg.de).
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*
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* The original version of this code was written by John Ioannidis
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* for BSD/OS in Athens, Greece, in November 1995.
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*
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* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
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* by Angelos D. Keromytis.
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*
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* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
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* and Niels Provos.
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*
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* Additional features in 1999 by Angelos D. Keromytis.
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*
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* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
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* Angelos D. Keromytis and Niels Provos.
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* Copyright (c) 2001 Angelos D. Keromytis.
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*
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* Permission to use, copy, and modify this software with or without fee
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* is hereby granted, provided that this entire notice is included in
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* all copies of any software which is or includes a copy or
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* modification of this software.
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* You may use this code under the GNU public license if you so wish. Please
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* contribute changes back to the authors under this freer than GPL license
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* so that we may further the use of strong encryption without limitations to
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* all.
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*
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* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
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* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
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* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
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* PURPOSE.
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*/
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include "opt_ipsec.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/syslog.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/random.h>
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#include <sys/mutex.h>
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#include <sys/sysctl.h>
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#include <sys/mutex.h>
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#include <machine/atomic.h>
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#include <net/if.h>
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#include <net/vnet.h>
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#include <netinet/in.h>
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#include <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <netinet/ip_ecn.h>
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#include <netinet/ip6.h>
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#include <netipsec/ipsec.h>
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#include <netipsec/ah.h>
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#include <netipsec/ah_var.h>
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#include <netipsec/esp.h>
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#include <netipsec/esp_var.h>
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#include <netipsec/xform.h>
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#ifdef INET6
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#include <netinet6/ip6_var.h>
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#include <netipsec/ipsec6.h>
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#include <netinet6/ip6_ecn.h>
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#endif
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#include <netipsec/key.h>
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#include <netipsec/key_debug.h>
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#include <opencrypto/cryptodev.h>
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#include <opencrypto/xform.h>
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VNET_DEFINE(int, esp_enable) = 1;
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VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1;
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#define V_esp_ctr_compatibility VNET(esp_ctr_compatibility)
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VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
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VNET_PCPUSTAT_SYSINIT(espstat);
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#ifdef VIMAGE
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VNET_PCPUSTAT_SYSUNINIT(espstat);
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#endif /* VIMAGE */
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SYSCTL_DECL(_net_inet_esp);
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SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
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SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility,
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CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0,
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"Align AES-CTR encrypted transmitted frames to blocksize");
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SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
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struct espstat, espstat,
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"ESP statistics (struct espstat, netipsec/esp_var.h");
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static int esp_input_cb(struct cryptop *op);
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static int esp_output_cb(struct cryptop *crp);
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size_t
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esp_hdrsiz(struct secasvar *sav)
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{
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size_t size;
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if (sav != NULL) {
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/*XXX not right for null algorithm--does it matter??*/
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IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
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("SA with null xform"));
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if (sav->flags & SADB_X_EXT_OLD)
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size = sizeof (struct esp);
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else
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size = sizeof (struct newesp);
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size += sav->tdb_encalgxform->blocksize + 9;
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/*XXX need alg check???*/
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if (sav->tdb_authalgxform != NULL && sav->replay)
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size += ah_hdrsiz(sav);
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} else {
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/*
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* base header size
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* + max iv length for CBC mode
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* + max pad length
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* + sizeof (pad length field)
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* + sizeof (next header field)
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* + max icv supported.
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*/
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size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
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}
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return size;
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}
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/*
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* esp_init() is called when an SPI is being set up.
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*/
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static int
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esp_init(struct secasvar *sav, struct xformsw *xsp)
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{
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const struct enc_xform *txform;
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struct crypto_session_params csp;
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int keylen;
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int error;
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txform = enc_algorithm_lookup(sav->alg_enc);
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if (txform == NULL) {
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DPRINTF(("%s: unsupported encryption algorithm %d\n",
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__func__, sav->alg_enc));
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return EINVAL;
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}
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if (sav->key_enc == NULL) {
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DPRINTF(("%s: no encoding key for %s algorithm\n",
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__func__, txform->name));
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return EINVAL;
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}
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if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
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SADB_X_EXT_IV4B) {
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DPRINTF(("%s: 4-byte IV not supported with protocol\n",
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__func__));
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return EINVAL;
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}
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/* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
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keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
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if (txform->minkey > keylen || keylen > txform->maxkey) {
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DPRINTF(("%s: invalid key length %u, must be in the range "
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"[%u..%u] for algorithm %s\n", __func__,
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keylen, txform->minkey, txform->maxkey,
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txform->name));
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return EINVAL;
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}
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if (SAV_ISCTRORGCM(sav))
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sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
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else
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sav->ivlen = txform->ivsize;
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memset(&csp, 0, sizeof(csp));
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/*
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* Setup AH-related state.
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*/
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if (sav->alg_auth != 0) {
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error = ah_init0(sav, xsp, &csp);
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if (error)
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return error;
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}
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/* NB: override anything set in ah_init0 */
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sav->tdb_xform = xsp;
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sav->tdb_encalgxform = txform;
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/*
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* Whenever AES-GCM is used for encryption, one
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* of the AES authentication algorithms is chosen
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* as well, based on the key size.
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*/
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if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
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switch (keylen) {
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case AES_128_GMAC_KEY_LEN:
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sav->alg_auth = SADB_X_AALG_AES128GMAC;
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sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
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break;
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case AES_192_GMAC_KEY_LEN:
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sav->alg_auth = SADB_X_AALG_AES192GMAC;
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sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
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break;
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case AES_256_GMAC_KEY_LEN:
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sav->alg_auth = SADB_X_AALG_AES256GMAC;
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sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
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break;
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default:
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DPRINTF(("%s: invalid key length %u"
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"for algorithm %s\n", __func__,
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keylen, txform->name));
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return EINVAL;
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}
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csp.csp_mode = CSP_MODE_AEAD;
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} else if (sav->alg_auth != 0)
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csp.csp_mode = CSP_MODE_ETA;
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else
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csp.csp_mode = CSP_MODE_CIPHER;
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/* Initialize crypto session. */
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csp.csp_cipher_alg = sav->tdb_encalgxform->type;
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if (csp.csp_cipher_alg != CRYPTO_NULL_CBC) {
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csp.csp_cipher_key = sav->key_enc->key_data;
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csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 -
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SAV_ISCTRORGCM(sav) * 4;
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};
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csp.csp_ivlen = txform->ivsize;
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error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
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return error;
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}
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static void
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esp_cleanup(struct secasvar *sav)
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{
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crypto_freesession(sav->tdb_cryptoid);
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sav->tdb_cryptoid = NULL;
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sav->tdb_authalgxform = NULL;
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sav->tdb_encalgxform = NULL;
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}
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/*
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* ESP input processing, called (eventually) through the protocol switch.
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*/
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static int
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esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
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{
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IPSEC_DEBUG_DECLARE(char buf[128]);
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const struct auth_hash *esph;
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const struct enc_xform *espx;
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struct xform_data *xd;
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struct cryptop *crp;
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struct newesp *esp;
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uint8_t *ivp;
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crypto_session_t cryptoid;
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int alen, error, hlen, plen;
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uint32_t seqh;
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IPSEC_ASSERT(sav != NULL, ("null SA"));
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IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
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error = EINVAL;
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/* Valid IP Packet length ? */
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if ( (skip&3) || (m->m_pkthdr.len&3) ){
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DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
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__func__, skip, m->m_pkthdr.len));
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ESPSTAT_INC(esps_badilen);
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goto bad;
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}
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if (m->m_len < skip + sizeof(*esp)) {
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m = m_pullup(m, skip + sizeof(*esp));
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if (m == NULL) {
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DPRINTF(("%s: cannot pullup header\n", __func__));
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ESPSTAT_INC(esps_hdrops); /*XXX*/
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error = ENOBUFS;
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goto bad;
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}
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}
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esp = (struct newesp *)(mtod(m, caddr_t) + skip);
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esph = sav->tdb_authalgxform;
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espx = sav->tdb_encalgxform;
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/* Determine the ESP header and auth length */
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if (sav->flags & SADB_X_EXT_OLD)
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hlen = sizeof (struct esp) + sav->ivlen;
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else
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hlen = sizeof (struct newesp) + sav->ivlen;
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alen = xform_ah_authsize(esph);
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/*
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* Verify payload length is multiple of encryption algorithm
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* block size.
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*
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* NB: This works for the null algorithm because the blocksize
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* is 4 and all packets must be 4-byte aligned regardless
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* of the algorithm.
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*/
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plen = m->m_pkthdr.len - (skip + hlen + alen);
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if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
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DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
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" SA %s/%08lx\n", __func__, plen, espx->blocksize,
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ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
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(u_long)ntohl(sav->spi)));
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ESPSTAT_INC(esps_badilen);
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goto bad;
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}
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/*
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* Check sequence number.
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*/
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SECASVAR_LOCK(sav);
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if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
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if (ipsec_chkreplay(ntohl(esp->esp_seq), &seqh, sav) == 0) {
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SECASVAR_UNLOCK(sav);
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DPRINTF(("%s: packet replay check for %s\n", __func__,
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ipsec_sa2str(sav, buf, sizeof(buf))));
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ESPSTAT_INC(esps_replay);
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error = EACCES;
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goto bad;
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}
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}
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cryptoid = sav->tdb_cryptoid;
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SECASVAR_UNLOCK(sav);
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/* Update the counters */
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ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
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/* Get crypto descriptors */
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crp = crypto_getreq(cryptoid, M_NOWAIT);
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if (crp == NULL) {
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DPRINTF(("%s: failed to acquire crypto descriptors\n",
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__func__));
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ESPSTAT_INC(esps_crypto);
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error = ENOBUFS;
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goto bad;
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}
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/* Get IPsec-specific opaque pointer */
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xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
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if (xd == NULL) {
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DPRINTF(("%s: failed to allocate xform_data\n", __func__));
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ESPSTAT_INC(esps_crypto);
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crypto_freereq(crp);
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error = ENOBUFS;
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goto bad;
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}
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if (esph != NULL) {
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crp->crp_op = CRYPTO_OP_VERIFY_DIGEST;
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crp->crp_aad_start = skip;
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if (SAV_ISGCM(sav))
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crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */
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else
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crp->crp_aad_length = hlen;
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crp->crp_digest_start = m->m_pkthdr.len - alen;
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}
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/* Crypto operation descriptor */
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crp->crp_flags = CRYPTO_F_CBIFSYNC;
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if (V_async_crypto)
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crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
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crypto_use_mbuf(crp, m);
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crp->crp_callback = esp_input_cb;
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crp->crp_opaque = xd;
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/* These are passed as-is to the callback */
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xd->sav = sav;
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xd->protoff = protoff;
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xd->skip = skip;
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xd->cryptoid = cryptoid;
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xd->vnet = curvnet;
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/* Decryption descriptor */
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crp->crp_op |= CRYPTO_OP_DECRYPT;
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crp->crp_payload_start = skip + hlen;
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crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen);
|
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|
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/* Generate or read cipher IV. */
|
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if (SAV_ISCTRORGCM(sav)) {
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ivp = &crp->crp_iv[0];
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|
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/*
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* AES-GCM and AES-CTR use similar cipher IV formats
|
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* defined in RFC 4106 section 4 and RFC 3686 section
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* 4, respectively.
|
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*
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* The first 4 bytes of the cipher IV contain an
|
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* implicit salt, or nonce, obtained from the last 4
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* bytes of the encryption key. The next 8 bytes hold
|
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* an explicit IV unique to each packet. This
|
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* explicit IV is used as the ESP IV for the packet.
|
|
* The last 4 bytes hold a big-endian block counter
|
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* incremented for each block. For AES-GCM, the block
|
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* counter's initial value is defined as part of the
|
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* algorithm. For AES-CTR, the block counter's
|
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* initial value for each packet is defined as 1 by
|
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* RFC 3686.
|
|
*
|
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* ------------------------------------------
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* | Salt | Explicit ESP IV | Block Counter |
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* ------------------------------------------
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* 4 bytes 8 bytes 4 bytes
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|
*/
|
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memcpy(ivp, sav->key_enc->key_data +
|
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_KEYLEN(sav->key_enc) - 4, 4);
|
|
m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
|
|
if (SAV_ISCTR(sav)) {
|
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be32enc(&ivp[sav->ivlen + 4], 1);
|
|
}
|
|
crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
|
|
} else if (sav->ivlen != 0)
|
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crp->crp_iv_start = skip + hlen - sav->ivlen;
|
|
|
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return (crypto_dispatch(crp));
|
|
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;
|
|
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)
|
|
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;
|
|
|
|
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));
|
|
}
|
|
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) {
|
|
crypto_freereq(crp);
|
|
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
|
|
ESPSTAT_INC(esps_crypto);
|
|
error = ENOBUFS;
|
|
goto bad;
|
|
}
|
|
|
|
/* 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;
|
|
if (V_async_crypto)
|
|
crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
|
|
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;
|
|
crp->crp_aad_start = skip;
|
|
if (SAV_ISGCM(sav))
|
|
crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */
|
|
else
|
|
crp->crp_aad_length = hlen;
|
|
crp->crp_digest_start = m->m_pkthdr.len - alen;
|
|
}
|
|
|
|
return crypto_dispatch(crp);
|
|
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);
|
|
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);
|
|
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);
|