freebsd-dev/sys/netipsec/xform_esp.c
Andrey V. Elsukov 3aee70991d Fix possible double releasing for SA and SP references.
There are two possible ways how crypto callback are called: directly from
caller and deffered from crypto thread.

For outbound packets the direct call chain is the following:
 IPSEC_OUTPUT() method -> ipsec[46]_common_output() ->
 -> ipsec[46]_perform_request() -> xform_output() ->
 -> crypto_dispatch() -> crypto_invoke() -> crypto_done() ->
 -> xform_output_cb() -> ipsec_process_done() -> ip[6]_output().

The SA and SP references are held while crypto processing is not finished.
The error handling code wrongly expected that crypto callback always called
from the crypto thread context, and it did references releasing in
xform_output_cb(). But when the crypto callback called directly, in case of
error the error handling code in ipsec[46]_perform_request() also did
references releasing.

To fix this, remove error handling from ipsec[46]_perform_request() and do it
in xform_output() before crypto_dispatch().

MFC after:	10 days
2017-05-23 09:32:26 +00:00

963 lines
25 KiB
C

/* $FreeBSD$ */
/* $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 <sys/param.h>
#include <sys/systm.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>
VNET_DEFINE(int, esp_enable) = 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_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 cryptoini cria, crie;
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;
/*
* Setup AH-related state.
*/
if (sav->alg_auth != 0) {
error = ah_init0(sav, xsp, &cria);
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;
}
bzero(&cria, sizeof(cria));
cria.cri_alg = sav->tdb_authalgxform->type;
cria.cri_key = sav->key_enc->key_data;
cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
}
/* Initialize crypto session. */
bzero(&crie, sizeof(crie));
crie.cri_alg = sav->tdb_encalgxform->type;
crie.cri_key = sav->key_enc->key_data;
crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
/* init both auth & enc */
crie.cri_next = &cria;
error = crypto_newsession(&sav->tdb_cryptoid,
&crie, V_crypto_support);
} else if (sav->tdb_encalgxform) {
error = crypto_newsession(&sav->tdb_cryptoid,
&crie, V_crypto_support);
} else if (sav->tdb_authalgxform) {
error = crypto_newsession(&sav->tdb_cryptoid,
&cria, V_crypto_support);
} else {
/* XXX cannot happen? */
DPRINTF(("%s: no encoding OR authentication xform!\n",
__func__));
error = EINVAL;
}
return error;
}
/*
* Paranoia.
*/
static int
esp_zeroize(struct secasvar *sav)
{
/* NB: ah_zerorize free's the crypto session state */
int error = ah_zeroize(sav);
if (sav->key_enc)
bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
sav->tdb_encalgxform = NULL;
sav->tdb_xform = NULL;
return error;
}
/*
* ESP input processing, called (eventually) through the protocol switch.
*/
static int
esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
char buf[128];
const struct auth_hash *esph;
const struct enc_xform *espx;
struct xform_data *xd;
struct cryptodesc *crde;
struct cryptop *crp;
struct newesp *esp;
uint8_t *ivp;
uint64_t cryptoid;
int alen, error, hlen, plen;
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;
}
/* XXX don't pullup, just copy header */
IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
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), 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;
}
}
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(esph && espx ? 2 : 1);
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) + alen, M_XDATA, M_NOWAIT | M_ZERO);
if (xd == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
ESPSTAT_INC(esps_crypto);
crypto_freereq(crp);
error = ENOBUFS;
goto bad;
}
if (esph != NULL) {
struct cryptodesc *crda = crp->crp_desc;
IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
/* Authentication descriptor */
crda->crd_skip = skip;
if (SAV_ISGCM(sav))
crda->crd_len = 8; /* RFC4106 5, SPI + SN */
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = m->m_pkthdr.len - alen;
crda->crd_alg = esph->type;
/* Copy the authenticator */
m_copydata(m, m->m_pkthdr.len - alen, alen,
(caddr_t) (xd + 1));
/* Chain authentication request */
crde = crda->crd_next;
} else {
crde = crp->crp_desc;
}
/* Crypto operation descriptor */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = esp_input_cb;
crp->crp_sid = cryptoid;
crp->crp_opaque = (caddr_t) xd;
/* These are passed as-is to the callback */
xd->sav = sav;
xd->protoff = protoff;
xd->skip = skip;
xd->cryptoid = cryptoid;
/* Decryption descriptor */
IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
crde->crd_skip = skip + hlen;
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_inject = skip + hlen - sav->ivlen;
if (SAV_ISCTRORGCM(sav)) {
ivp = &crde->crd_iv[0];
/* GCM IV Format: RFC4106 4 */
/* CTR IV Format: RFC3686 4 */
/* Salt is last four bytes of key, RFC4106 8.1 */
/* Nonce is last four bytes of key, RFC3686 5.1 */
memcpy(ivp, sav->key_enc->key_data +
_KEYLEN(sav->key_enc) - 4, 4);
if (SAV_ISCTR(sav)) {
/* Initial block counter is 1, RFC3686 4 */
be32enc(&ivp[sav->ivlen + 4], 1);
}
m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
crde->crd_flags |= CRD_F_IV_EXPLICIT;
}
crde->crd_alg = espx->type;
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)
{
char buf[128];
u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
const struct auth_hash *esph;
const struct enc_xform *espx;
struct mbuf *m;
struct cryptodesc *crd;
struct xform_data *xd;
struct secasvar *sav;
struct secasindex *saidx;
caddr_t ptr;
uint64_t cryptoid;
int hlen, skip, protoff, error, alen;
crd = crp->crp_desc;
IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
m = (struct mbuf *) crp->crp_buf;
xd = (struct xform_data *) crp->crp_opaque;
sav = xd->sav;
skip = xd->skip;
protoff = xd->protoff;
cryptoid = xd->cryptoid;
saidx = &sav->sah->saidx;
esph = sav->tdb_authalgxform;
espx = sav->tdb_encalgxform;
/* Check for crypto errors */
if (crp->crp_etype) {
if (crp->crp_etype == EAGAIN) {
/* Reset the session ID */
if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
crypto_freesession(cryptoid);
xd->cryptoid = crp->crp_sid;
return (crypto_dispatch(crp));
}
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]);
/* Copy the authenticator from the packet */
m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
ptr = (caddr_t) (xd + 1);
/* Verify authenticator */
if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
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;
}
}
/* 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);
}
return error;
bad:
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)
{
char buf[IPSEC_ADDRSTRLEN];
struct cryptodesc *crde = NULL, *crda = NULL;
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, 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.
*/
blks = MAX(4, espx->blocksize); /* Cipher 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(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:
(void) read_random(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 descriptors. */
crp = crypto_getreq(esph != NULL ? 2 : 1);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptors\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;
}
crde = crp->crp_desc;
crda = crde->crd_next;
/* Encryption descriptor. */
crde->crd_skip = skip + hlen;
crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
crde->crd_flags = CRD_F_ENCRYPT;
crde->crd_inject = skip + hlen - sav->ivlen;
/* Encryption operation. */
crde->crd_alg = espx->type;
if (SAV_ISCTRORGCM(sav)) {
ivp = &crde->crd_iv[0];
/* GCM IV Format: RFC4106 4 */
/* CTR IV Format: RFC3686 4 */
/* Salt is last four bytes of key, RFC4106 8.1 */
/* Nonce is last four bytes of key, RFC3686 5.1 */
memcpy(ivp, sav->key_enc->key_data +
_KEYLEN(sav->key_enc) - 4, 4);
be64enc(&ivp[4], cntr);
if (SAV_ISCTR(sav)) {
/* Initial block counter is 1, RFC3686 4 */
/* XXXAE: should we use this only for first packet? */
be32enc(&ivp[sav->ivlen + 4], 1);
}
m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
}
/* Callback parameters */
xd->sp = sp;
xd->sav = sav;
xd->idx = idx;
xd->cryptoid = cryptoid;
/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = esp_output_cb;
crp->crp_opaque = (caddr_t) xd;
crp->crp_sid = cryptoid;
if (esph) {
/* Authentication descriptor. */
crda->crd_alg = esph->type;
crda->crd_skip = skip;
if (SAV_ISGCM(sav))
crda->crd_len = 8; /* RFC4106 5, SPI + SN */
else
crda->crd_len = m->m_pkthdr.len - (skip + alen);
crda->crd_inject = 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;
uint64_t cryptoid;
u_int idx;
int error;
xd = (struct xform_data *) crp->crp_opaque;
m = (struct mbuf *) crp->crp_buf;
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_sid, &cryptoid) != 0)
crypto_freesession(cryptoid);
xd->cryptoid = crp->crp_sid;
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);
return (error);
bad:
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_zeroize = esp_zeroize,
.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);