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freebsd-skq/sys/netipsec/xform_esp.c
Mark Johnston 68f6800ce0 opencrypto: Introduce crypto_dispatch_async() 
Currently, OpenCrypto consumers can request asynchronous dispatch by
setting a flag in the cryptop.  (Currently only IPSec may do this.)   I
think this is a bit confusing: we (conditionally) set cryptop flags to
request async dispatch, and then crypto_dispatch() immediately examines
those flags to see if the consumer wants async dispatch. The flag names
are also confusing since they don't specify what "async" applies to:
dispatch or completion.

Add a new KPI, crypto_dispatch_async(), rather than encoding the
requested dispatch type in each cryptop. crypto_dispatch_async() falls
back to crypto_dispatch() if the session's driver provides asynchronous
dispatch. Get rid of CRYPTOP_ASYNC() and CRYPTOP_ASYNC_KEEPORDER().

Similarly, add crypto_dispatch_batch() to request processing of a tailq
of cryptops, rather than encoding the scheduling policy using cryptop
flags.  Convert GELI, the only user of this interface (disabled by
default) to use the new interface.

Add CRYPTO_SESS_SYNC(), which can be used by consumers to determine
whether crypto requests will be dispatched synchronously. This is just
a helper macro. Use it instead of looking at cap flags directly.

Fix style in crypto_done(). Also get rid of CRYPTO_RETW_EMPTY() and
just check the relevant queues directly. This could result in some
unnecessary wakeups but I think it's very uncommon to be using more than
one queue per worker in a given workload, so checking all three queues
is a waste of cycles.

Reviewed by:	jhb
Sponsored by:	Ampere Computing
Submitted by:	Klara, Inc.
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D28194
2021-02-08 09:19:19 -05:00

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/* $FreeBSD$ */
/* $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
/*-
* The authors of this code are John Ioannidis (ji@tla.org),
* Angelos D. Keromytis (kermit@csd.uch.gr) and
* Niels Provos (provos@physnet.uni-hamburg.de).
*
* The original version of this code was written by John Ioannidis
* for BSD/OS in Athens, Greece, in November 1995.
*
* Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
* by Angelos D. Keromytis.
*
* Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
* and Niels Provos.
*
* Additional features in 1999 by Angelos D. Keromytis.
*
* Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
* Copyright (c) 2001 Angelos D. Keromytis.
*
* Permission to use, copy, and modify this software with or without fee
* is hereby granted, provided that this entire notice is included in
* all copies of any software which is or includes a copy or
* modification of this software.
* You may use this code under the GNU public license if you so wish. Please
* contribute changes back to the authors under this freer than GPL license
* so that we may further the use of strong encryption without limitations to
* all.
*
* THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
* REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
* MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
* PURPOSE.
*/
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include <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>
#define SPI_SIZE 4
VNET_DEFINE(int, esp_enable) = 1;
VNET_DEFINE_STATIC(int, esp_ctr_compatibility) = 1;
#define V_esp_ctr_compatibility VNET(esp_ctr_compatibility)
VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
VNET_PCPUSTAT_SYSINIT(espstat);
#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(espstat);
#endif /* VIMAGE */
SYSCTL_DECL(_net_inet_esp);
SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
SYSCTL_INT(_net_inet_esp, OID_AUTO, ctr_compatibility,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_ctr_compatibility), 0,
"Align AES-CTR encrypted transmitted frames to blocksize");
SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
struct espstat, espstat,
"ESP statistics (struct espstat, netipsec/esp_var.h");
static int esp_input_cb(struct cryptop *op);
static int esp_output_cb(struct cryptop *crp);
size_t
esp_hdrsiz(struct secasvar *sav)
{
size_t size;
if (sav != NULL) {
/*XXX not right for null algorithm--does it matter??*/
IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
("SA with null xform"));
if (sav->flags & SADB_X_EXT_OLD)
size = sizeof (struct esp);
else
size = sizeof (struct newesp);
size += sav->tdb_encalgxform->blocksize + 9;
/*XXX need alg check???*/
if (sav->tdb_authalgxform != NULL && sav->replay)
size += ah_hdrsiz(sav);
} else {
/*
* base header size
* + max iv length for CBC mode
* + max pad length
* + sizeof (pad length field)
* + sizeof (next header field)
* + max icv supported.
*/
size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
}
return size;
}
/*
* esp_init() is called when an SPI is being set up.
*/
static int
esp_init(struct secasvar *sav, struct xformsw *xsp)
{
const struct enc_xform *txform;
struct crypto_session_params csp;
int keylen;
int error;
txform = enc_algorithm_lookup(sav->alg_enc);
if (txform == NULL) {
DPRINTF(("%s: unsupported encryption algorithm %d\n",
__func__, sav->alg_enc));
return EINVAL;
}
if (sav->key_enc == NULL) {
DPRINTF(("%s: no encoding key for %s algorithm\n",
__func__, txform->name));
return EINVAL;
}
if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
SADB_X_EXT_IV4B) {
DPRINTF(("%s: 4-byte IV not supported with protocol\n",
__func__));
return EINVAL;
}
/* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
if (txform->minkey > keylen || keylen > txform->maxkey) {
DPRINTF(("%s: invalid key length %u, must be in the range "
"[%u..%u] for algorithm %s\n", __func__,
keylen, txform->minkey, txform->maxkey,
txform->name));
return EINVAL;
}
if (SAV_ISCTRORGCM(sav))
sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
else
sav->ivlen = txform->ivsize;
memset(&csp, 0, sizeof(csp));
/*
* Setup AH-related state.
*/
if (sav->alg_auth != 0) {
error = ah_init0(sav, xsp, &csp);
if (error)
return error;
}
/* NB: override anything set in ah_init0 */
sav->tdb_xform = xsp;
sav->tdb_encalgxform = txform;
/*
* Whenever AES-GCM is used for encryption, one
* of the AES authentication algorithms is chosen
* as well, based on the key size.
*/
if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
switch (keylen) {
case AES_128_GMAC_KEY_LEN:
sav->alg_auth = SADB_X_AALG_AES128GMAC;
sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
break;
case AES_192_GMAC_KEY_LEN:
sav->alg_auth = SADB_X_AALG_AES192GMAC;
sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
break;
case AES_256_GMAC_KEY_LEN:
sav->alg_auth = SADB_X_AALG_AES256GMAC;
sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
break;
default:
DPRINTF(("%s: invalid key length %u"
"for algorithm %s\n", __func__,
keylen, txform->name));
return EINVAL;
}
csp.csp_mode = CSP_MODE_AEAD;
if (sav->flags & SADB_X_SAFLAGS_ESN)
csp.csp_flags |= CSP_F_SEPARATE_AAD;
} else if (sav->alg_auth != 0) {
csp.csp_mode = CSP_MODE_ETA;
if (sav->flags & SADB_X_SAFLAGS_ESN)
csp.csp_flags |= CSP_F_ESN;
} else
csp.csp_mode = CSP_MODE_CIPHER;
/* Initialize crypto session. */
csp.csp_cipher_alg = sav->tdb_encalgxform->type;
if (csp.csp_cipher_alg != CRYPTO_NULL_CBC) {
csp.csp_cipher_key = sav->key_enc->key_data;
csp.csp_cipher_klen = _KEYBITS(sav->key_enc) / 8 -
SAV_ISCTRORGCM(sav) * 4;
};
csp.csp_ivlen = txform->ivsize;
error = crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support);
return error;
}
static void
esp_cleanup(struct secasvar *sav)
{
crypto_freesession(sav->tdb_cryptoid);
sav->tdb_cryptoid = NULL;
sav->tdb_authalgxform = NULL;
sav->tdb_encalgxform = NULL;
}
/*
* ESP input processing, called (eventually) through the protocol switch.
*/
static int
esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
IPSEC_DEBUG_DECLARE(char buf[128]);
const struct auth_hash *esph;
const struct enc_xform *espx;
struct xform_data *xd;
struct cryptop *crp;
struct newesp *esp;
uint8_t *ivp;
crypto_session_t cryptoid;
int alen, error, hlen, plen;
uint32_t seqh;
const struct crypto_session_params *csp;
IPSEC_ASSERT(sav != NULL, ("null SA"));
IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
error = EINVAL;
/* Valid IP Packet length ? */
if ( (skip&3) || (m->m_pkthdr.len&3) ){
DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
__func__, skip, m->m_pkthdr.len));
ESPSTAT_INC(esps_badilen);
goto bad;
}
if (m->m_len < skip + sizeof(*esp)) {
m = m_pullup(m, skip + sizeof(*esp));
if (m == NULL) {
DPRINTF(("%s: cannot pullup header\n", __func__));
ESPSTAT_INC(esps_hdrops); /*XXX*/
error = ENOBUFS;
goto bad;
}
}
esp = (struct newesp *)(mtod(m, caddr_t) + skip);
esph = sav->tdb_authalgxform;
espx = sav->tdb_encalgxform;
/* Determine the ESP header and auth length */
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof (struct esp) + sav->ivlen;
else
hlen = sizeof (struct newesp) + sav->ivlen;
alen = xform_ah_authsize(esph);
/*
* Verify payload length is multiple of encryption algorithm
* block size.
*
* NB: This works for the null algorithm because the blocksize
* is 4 and all packets must be 4-byte aligned regardless
* of the algorithm.
*/
plen = m->m_pkthdr.len - (skip + hlen + alen);
if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
" SA %s/%08lx\n", __func__, plen, espx->blocksize,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long)ntohl(sav->spi)));
ESPSTAT_INC(esps_badilen);
goto bad;
}
/*
* Check sequence number.
*/
SECASVAR_LOCK(sav);
if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
if (ipsec_chkreplay(ntohl(esp->esp_seq), &seqh, sav) == 0) {
SECASVAR_UNLOCK(sav);
DPRINTF(("%s: packet replay check for %s\n", __func__,
ipsec_sa2str(sav, buf, sizeof(buf))));
ESPSTAT_INC(esps_replay);
error = EACCES;
goto bad;
}
seqh = htonl(seqh);
}
cryptoid = sav->tdb_cryptoid;
SECASVAR_UNLOCK(sav);
/* Update the counters */
ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
/* Get crypto descriptors */
crp = crypto_getreq(cryptoid, M_NOWAIT);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptors\n",
__func__));
ESPSTAT_INC(esps_crypto);
error = ENOBUFS;
goto bad;
}
/* Get IPsec-specific opaque pointer */
xd = malloc(sizeof(*xd), M_XDATA, M_NOWAIT | M_ZERO);
if (xd == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
goto xd_fail;
}
if (esph != NULL) {
crp->crp_op = CRYPTO_OP_VERIFY_DIGEST;
if (SAV_ISGCM(sav))
crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */
else
crp->crp_aad_length = hlen;
csp = crypto_get_params(crp->crp_session);
if ((csp->csp_flags & CSP_F_SEPARATE_AAD) &&
(sav->replay != NULL) && (sav->replay->wsize != 0)) {
int aad_skip;
crp->crp_aad_length += sizeof(seqh);
crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT);
if (crp->crp_aad == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n",
__func__));
goto crp_aad_fail;
}
/* SPI */
m_copydata(m, skip, SPI_SIZE, crp->crp_aad);
aad_skip = SPI_SIZE;
/* ESN */
bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh));
aad_skip += sizeof(seqh);
/* Rest of aad */
if (crp->crp_aad_length - aad_skip > 0)
m_copydata(m, skip + SPI_SIZE,
crp->crp_aad_length - aad_skip,
(char *)crp->crp_aad + aad_skip);
} else
crp->crp_aad_start = skip;
if (csp->csp_flags & CSP_F_ESN &&
sav->replay != NULL && sav->replay->wsize != 0)
memcpy(crp->crp_esn, &seqh, sizeof(seqh));
crp->crp_digest_start = m->m_pkthdr.len - alen;
}
/* Crypto operation descriptor */
crp->crp_flags = CRYPTO_F_CBIFSYNC;
crypto_use_mbuf(crp, m);
crp->crp_callback = esp_input_cb;
crp->crp_opaque = xd;
/* These are passed as-is to the callback */
xd->sav = sav;
xd->protoff = protoff;
xd->skip = skip;
xd->cryptoid = cryptoid;
xd->vnet = curvnet;
/* Decryption descriptor */
crp->crp_op |= CRYPTO_OP_DECRYPT;
crp->crp_payload_start = skip + hlen;
crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen);
/* Generate or read cipher IV. */
if (SAV_ISCTRORGCM(sav)) {
ivp = &crp->crp_iv[0];
/*
* AES-GCM and AES-CTR use similar cipher IV formats
* defined in RFC 4106 section 4 and RFC 3686 section
* 4, respectively.
*
* The first 4 bytes of the cipher IV contain an
* implicit salt, or nonce, obtained from the last 4
* bytes of the encryption key. The next 8 bytes hold
* an explicit IV unique to each packet. This
* explicit IV is used as the ESP IV for the packet.
* The last 4 bytes hold a big-endian block counter
* incremented for each block. For AES-GCM, the block
* counter's initial value is defined as part of the
* algorithm. For AES-CTR, the block counter's
* initial value for each packet is defined as 1 by
* RFC 3686.
*
* ------------------------------------------
* | Salt | Explicit ESP IV | Block Counter |
* ------------------------------------------
* 4 bytes 8 bytes 4 bytes
*/
memcpy(ivp, sav->key_enc->key_data +
_KEYLEN(sav->key_enc) - 4, 4);
m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
if (SAV_ISCTR(sav)) {
be32enc(&ivp[sav->ivlen + 4], 1);
}
crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
} else if (sav->ivlen != 0)
crp->crp_iv_start = skip + hlen - sav->ivlen;
if (V_async_crypto)
return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED));
else
return (crypto_dispatch(crp));
crp_aad_fail:
free(xd, M_XDATA);
xd_fail:
crypto_freereq(crp);
ESPSTAT_INC(esps_crypto);
error = ENOBUFS;
bad:
m_freem(m);
key_freesav(&sav);
return (error);
}
/*
* ESP input callback from the crypto driver.
*/
static int
esp_input_cb(struct cryptop *crp)
{
IPSEC_DEBUG_DECLARE(char buf[128]);
uint8_t lastthree[3];
const struct auth_hash *esph;
struct mbuf *m;
struct xform_data *xd;
struct secasvar *sav;
struct secasindex *saidx;
crypto_session_t cryptoid;
int hlen, skip, protoff, error, alen;
m = crp->crp_buf.cb_mbuf;
xd = crp->crp_opaque;
CURVNET_SET(xd->vnet);
sav = xd->sav;
skip = xd->skip;
protoff = xd->protoff;
cryptoid = xd->cryptoid;
saidx = &sav->sah->saidx;
esph = sav->tdb_authalgxform;
/* Check for crypto errors */
if (crp->crp_etype) {
if (crp->crp_etype == EAGAIN) {
/* Reset the session ID */
if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
crypto_freesession(cryptoid);
xd->cryptoid = crp->crp_session;
CURVNET_RESTORE();
return (crypto_dispatch(crp));
}
/* EBADMSG indicates authentication failure. */
if (!(crp->crp_etype == EBADMSG && esph != NULL)) {
ESPSTAT_INC(esps_noxform);
DPRINTF(("%s: crypto error %d\n", __func__,
crp->crp_etype));
error = crp->crp_etype;
goto bad;
}
}
/* Shouldn't happen... */
if (m == NULL) {
ESPSTAT_INC(esps_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
ESPSTAT_INC(esps_hist[sav->alg_enc]);
/* If authentication was performed, check now. */
if (esph != NULL) {
alen = xform_ah_authsize(esph);
AHSTAT_INC(ahs_hist[sav->alg_auth]);
if (crp->crp_etype == EBADMSG) {
DPRINTF(("%s: authentication hash mismatch for "
"packet in SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
ESPSTAT_INC(esps_badauth);
error = EACCES;
goto bad;
}
m->m_flags |= M_AUTHIPDGM;
/* Remove trailing authenticator */
m_adj(m, -alen);
}
/* Release the crypto descriptors */
free(xd, M_XDATA), xd = NULL;
free(crp->crp_aad, M_XDATA), crp->crp_aad = NULL;
crypto_freereq(crp), crp = NULL;
/*
* Packet is now decrypted.
*/
m->m_flags |= M_DECRYPTED;
/*
* Update replay sequence number, if appropriate.
*/
if (sav->replay) {
u_int32_t seq;
m_copydata(m, skip + offsetof(struct newesp, esp_seq),
sizeof (seq), (caddr_t) &seq);
SECASVAR_LOCK(sav);
if (ipsec_updatereplay(ntohl(seq), sav)) {
SECASVAR_UNLOCK(sav);
DPRINTF(("%s: packet replay check for %s\n", __func__,
ipsec_sa2str(sav, buf, sizeof(buf))));
ESPSTAT_INC(esps_replay);
error = EACCES;
goto bad;
}
SECASVAR_UNLOCK(sav);
}
/* Determine the ESP header length */
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof (struct esp) + sav->ivlen;
else
hlen = sizeof (struct newesp) + sav->ivlen;
/* Remove the ESP header and IV from the mbuf. */
error = m_striphdr(m, skip, hlen);
if (error) {
ESPSTAT_INC(esps_hdrops);
DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
goto bad;
}
/* Save the last three bytes of decrypted data */
m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
/* Verify pad length */
if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
ESPSTAT_INC(esps_badilen);
DPRINTF(("%s: invalid padding length %d for %u byte packet "
"in SA %s/%08lx\n", __func__, lastthree[1],
m->m_pkthdr.len - skip,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
error = EINVAL;
goto bad;
}
/* Verify correct decryption by checking the last padding bytes */
if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
ESPSTAT_INC(esps_badenc);
DPRINTF(("%s: decryption failed for packet in "
"SA %s/%08lx\n", __func__, ipsec_address(
&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
error = EINVAL;
goto bad;
}
}
/*
* RFC4303 2.6:
* Silently drop packet if next header field is IPPROTO_NONE.
*/
if (lastthree[2] == IPPROTO_NONE)
goto bad;
/* Trim the mbuf chain to remove trailing authenticator and padding */
m_adj(m, -(lastthree[1] + 2));
/* Restore the Next Protocol field */
m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
switch (saidx->dst.sa.sa_family) {
#ifdef INET6
case AF_INET6:
error = ipsec6_common_input_cb(m, sav, skip, protoff);
break;
#endif
#ifdef INET
case AF_INET:
error = ipsec4_common_input_cb(m, sav, skip, protoff);
break;
#endif
default:
panic("%s: Unexpected address family: %d saidx=%p", __func__,
saidx->dst.sa.sa_family, saidx);
}
CURVNET_RESTORE();
return error;
bad:
CURVNET_RESTORE();
if (sav != NULL)
key_freesav(&sav);
if (m != NULL)
m_freem(m);
if (xd != NULL)
free(xd, M_XDATA);
if (crp != NULL) {
free(crp->crp_aad, M_XDATA);
crypto_freereq(crp);
}
return error;
}
/*
* ESP output routine, called by ipsec[46]_perform_request().
*/
static int
esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
u_int idx, int skip, int protoff)
{
IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
struct cryptop *crp;
const struct auth_hash *esph;
const struct enc_xform *espx;
struct mbuf *mo = NULL;
struct xform_data *xd;
struct secasindex *saidx;
unsigned char *pad;
uint8_t *ivp;
uint64_t cntr;
crypto_session_t cryptoid;
int hlen, rlen, padding, blks, alen, i, roff;
int error, maxpacketsize;
uint8_t prot;
uint32_t seqh;
const struct crypto_session_params *csp;
IPSEC_ASSERT(sav != NULL, ("null SA"));
esph = sav->tdb_authalgxform;
espx = sav->tdb_encalgxform;
IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
if (sav->flags & SADB_X_EXT_OLD)
hlen = sizeof (struct esp) + sav->ivlen;
else
hlen = sizeof (struct newesp) + sav->ivlen;
rlen = m->m_pkthdr.len - skip; /* Raw payload length. */
/*
* RFC4303 2.4 Requires 4 byte alignment.
* Old versions of FreeBSD can't decrypt partial blocks encrypted
* with AES-CTR. Align payload to native_blocksize (16 bytes)
* in order to preserve compatibility.
*/
if (SAV_ISCTR(sav) && V_esp_ctr_compatibility)
blks = MAX(4, espx->native_blocksize); /* Cipher blocksize */
else
blks = MAX(4, espx->blocksize);
/* XXX clamp padding length a la KAME??? */
padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
alen = xform_ah_authsize(esph);
ESPSTAT_INC(esps_output);
saidx = &sav->sah->saidx;
/* Check for maximum packet size violations. */
switch (saidx->dst.sa.sa_family) {
#ifdef INET
case AF_INET:
maxpacketsize = IP_MAXPACKET;
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
maxpacketsize = IPV6_MAXPACKET;
break;
#endif /* INET6 */
default:
DPRINTF(("%s: unknown/unsupported protocol "
"family %d, SA %s/%08lx\n", __func__,
saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
ESPSTAT_INC(esps_nopf);
error = EPFNOSUPPORT;
goto bad;
}
/*
DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
__func__, skip, hlen, rlen, padding, alen, blks)); */
if (skip + hlen + rlen + padding + alen > maxpacketsize) {
DPRINTF(("%s: packet in SA %s/%08lx got too big "
"(len %u, max len %u)\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi),
skip + hlen + rlen + padding + alen, maxpacketsize));
ESPSTAT_INC(esps_toobig);
error = EMSGSIZE;
goto bad;
}
/* Update the counters. */
ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
m = m_unshare(m, M_NOWAIT);
if (m == NULL) {
DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
ESPSTAT_INC(esps_hdrops);
error = ENOBUFS;
goto bad;
}
/* Inject ESP header. */
mo = m_makespace(m, skip, hlen, &roff);
if (mo == NULL) {
DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
__func__, hlen, ipsec_address(&saidx->dst, buf,
sizeof(buf)), (u_long) ntohl(sav->spi)));
ESPSTAT_INC(esps_hdrops); /* XXX diffs from openbsd */
error = ENOBUFS;
goto bad;
}
/* Initialize ESP header. */
bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
sizeof(uint32_t));
SECASVAR_LOCK(sav);
if (sav->replay) {
uint32_t replay;
#ifdef REGRESSION
/* Emulate replay attack when ipsec_replay is TRUE. */
if (!V_ipsec_replay)
#endif
sav->replay->count++;
replay = htonl((uint32_t)sav->replay->count);
bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
sizeof(uint32_t), sizeof(uint32_t));
seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT));
}
cryptoid = sav->tdb_cryptoid;
if (SAV_ISCTRORGCM(sav))
cntr = sav->cntr++;
SECASVAR_UNLOCK(sav);
/*
* Add padding -- better to do it ourselves than use the crypto engine,
* although if/when we support compression, we'd have to do that.
*/
pad = (u_char *) m_pad(m, padding + alen);
if (pad == NULL) {
DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
m = NULL; /* NB: free'd by m_pad */
error = ENOBUFS;
goto bad;
}
/*
* Add padding: random, zero, or self-describing.
* XXX catch unexpected setting
*/
switch (sav->flags & SADB_X_EXT_PMASK) {
case SADB_X_EXT_PRAND:
arc4random_buf(pad, padding - 2);
break;
case SADB_X_EXT_PZERO:
bzero(pad, padding - 2);
break;
case SADB_X_EXT_PSEQ:
for (i = 0; i < padding - 2; i++)
pad[i] = i+1;
break;
}
/* Fix padding length and Next Protocol in padding itself. */
pad[padding - 2] = padding - 2;
m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
/* Fix Next Protocol in IPv4/IPv6 header. */
prot = IPPROTO_ESP;
m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
/* Get crypto descriptor. */
crp = crypto_getreq(cryptoid, M_NOWAIT);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptor\n",
__func__));
ESPSTAT_INC(esps_crypto);
error = ENOBUFS;
goto bad;
}
/* IPsec-specific opaque crypto info. */
xd = malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
if (xd == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
goto xd_fail;
}
/* Encryption descriptor. */
crp->crp_payload_start = skip + hlen;
crp->crp_payload_length = m->m_pkthdr.len - (skip + hlen + alen);
crp->crp_op = CRYPTO_OP_ENCRYPT;
/* Generate cipher and ESP IVs. */
ivp = &crp->crp_iv[0];
if (SAV_ISCTRORGCM(sav)) {
/*
* See comment in esp_input() for details on the
* cipher IV. A simple per-SA counter stored in
* 'cntr' is used as the explicit ESP IV.
*/
memcpy(ivp, sav->key_enc->key_data +
_KEYLEN(sav->key_enc) - 4, 4);
be64enc(&ivp[4], cntr);
if (SAV_ISCTR(sav)) {
be32enc(&ivp[sav->ivlen + 4], 1);
}
m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
crp->crp_flags |= CRYPTO_F_IV_SEPARATE;
} else if (sav->ivlen != 0) {
arc4rand(ivp, sav->ivlen, 0);
crp->crp_iv_start = skip + hlen - sav->ivlen;
m_copyback(m, crp->crp_iv_start, sav->ivlen, ivp);
}
/* Callback parameters */
xd->sp = sp;
xd->sav = sav;
xd->idx = idx;
xd->cryptoid = cryptoid;
xd->vnet = curvnet;
/* Crypto operation descriptor. */
crp->crp_flags |= CRYPTO_F_CBIFSYNC;
crypto_use_mbuf(crp, m);
crp->crp_callback = esp_output_cb;
crp->crp_opaque = xd;
if (esph) {
/* Authentication descriptor. */
crp->crp_op |= CRYPTO_OP_COMPUTE_DIGEST;
if (SAV_ISGCM(sav))
crp->crp_aad_length = 8; /* RFC4106 5, SPI + SN */
else
crp->crp_aad_length = hlen;
csp = crypto_get_params(crp->crp_session);
if (csp->csp_flags & CSP_F_SEPARATE_AAD &&
sav->replay != NULL) {
int aad_skip;
crp->crp_aad_length += sizeof(seqh);
crp->crp_aad = malloc(crp->crp_aad_length, M_XDATA, M_NOWAIT);
if (crp->crp_aad == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n",
__func__));
goto crp_aad_fail;
}
/* SPI */
m_copydata(m, skip, SPI_SIZE, crp->crp_aad);
aad_skip = SPI_SIZE;
/* ESN */
bcopy(&seqh, (char *)crp->crp_aad + aad_skip, sizeof(seqh));
aad_skip += sizeof(seqh);
/* Rest of aad */
if (crp->crp_aad_length - aad_skip > 0)
m_copydata(m, skip + SPI_SIZE,
crp->crp_aad_length - aad_skip,
(char *)crp->crp_aad + aad_skip);
} else
crp->crp_aad_start = skip;
if (csp->csp_flags & CSP_F_ESN && sav->replay != NULL)
memcpy(crp->crp_esn, &seqh, sizeof(seqh));
crp->crp_digest_start = m->m_pkthdr.len - alen;
}
if (V_async_crypto)
return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED));
else
return (crypto_dispatch(crp));
crp_aad_fail:
free(xd, M_XDATA);
xd_fail:
crypto_freereq(crp);
ESPSTAT_INC(esps_crypto);
error = ENOBUFS;
bad:
if (m)
m_freem(m);
key_freesav(&sav);
key_freesp(&sp);
return (error);
}
/*
* ESP output callback from the crypto driver.
*/
static int
esp_output_cb(struct cryptop *crp)
{
struct xform_data *xd;
struct secpolicy *sp;
struct secasvar *sav;
struct mbuf *m;
crypto_session_t cryptoid;
u_int idx;
int error;
xd = (struct xform_data *) crp->crp_opaque;
CURVNET_SET(xd->vnet);
m = crp->crp_buf.cb_mbuf;
sp = xd->sp;
sav = xd->sav;
idx = xd->idx;
cryptoid = xd->cryptoid;
/* Check for crypto errors. */
if (crp->crp_etype) {
if (crp->crp_etype == EAGAIN) {
/* Reset the session ID */
if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
crypto_freesession(cryptoid);
xd->cryptoid = crp->crp_session;
CURVNET_RESTORE();
return (crypto_dispatch(crp));
}
ESPSTAT_INC(esps_noxform);
DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
error = crp->crp_etype;
m_freem(m);
goto bad;
}
/* Shouldn't happen... */
if (m == NULL) {
ESPSTAT_INC(esps_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
free(xd, M_XDATA);
free(crp->crp_aad, M_XDATA);
crypto_freereq(crp);
ESPSTAT_INC(esps_hist[sav->alg_enc]);
if (sav->tdb_authalgxform != NULL)
AHSTAT_INC(ahs_hist[sav->alg_auth]);
#ifdef REGRESSION
/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
if (V_ipsec_integrity) {
static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
const struct auth_hash *esph;
/*
* Corrupt HMAC if we want to test integrity verification of
* the other side.
*/
esph = sav->tdb_authalgxform;
if (esph != NULL) {
int alen;
alen = xform_ah_authsize(esph);
m_copyback(m, m->m_pkthdr.len - alen,
alen, ipseczeroes);
}
}
#endif
/* NB: m is reclaimed by ipsec_process_done. */
error = ipsec_process_done(m, sp, sav, idx);
CURVNET_RESTORE();
return (error);
bad:
CURVNET_RESTORE();
free(xd, M_XDATA);
free(crp->crp_aad, M_XDATA);
crypto_freereq(crp);
key_freesav(&sav);
key_freesp(&sp);
return (error);
}
static struct xformsw esp_xformsw = {
.xf_type = XF_ESP,
.xf_name = "IPsec ESP",
.xf_init = esp_init,
.xf_cleanup = esp_cleanup,
.xf_input = esp_input,
.xf_output = esp_output,
};
SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
xform_attach, &esp_xformsw);
SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
xform_detach, &esp_xformsw);
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