d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
9c0e3d3a53
freebsd-dev/sys/netipsec/xform_esp.c
John Baldwin 9c0e3d3a53 Add support for optional separate output buffers to in-kernel crypto. 
Some crypto consumers such as GELI and KTLS for file-backed sendfile
need to store their output in a separate buffer from the input.
Currently these consumers copy the contents of the input buffer into
the output buffer and queue an in-place crypto operation on the output
buffer.  Using a separate output buffer avoids this copy.

- Create a new 'struct crypto_buffer' describing a crypto buffer
  containing a type and type-specific fields.  crp_ilen is gone,
  instead buffers that use a flat kernel buffer have a cb_buf_len
  field for their length.  The length of other buffer types is
  inferred from the backing store (e.g. uio_resid for a uio).
  Requests now have two such structures: crp_buf for the input buffer,
  and crp_obuf for the output buffer.

- Consumers now use helper functions (crypto_use_*,
  e.g. crypto_use_mbuf()) to configure the input buffer.  If an output
  buffer is not configured, the request still modifies the input
  buffer in-place.  A consumer uses a second set of helper functions
  (crypto_use_output_*) to configure an output buffer.

- Consumers must request support for separate output buffers when
  creating a crypto session via the CSP_F_SEPARATE_OUTPUT flag and are
  only permitted to queue a request with a separate output buffer on
  sessions with this flag set.  Existing drivers already reject
  sessions with unknown flags, so this permits drivers to be modified
  to support this extension without requiring all drivers to change.

- Several data-related functions now have matching versions that
  operate on an explicit buffer (e.g. crypto_apply_buf,
  crypto_contiguous_subsegment_buf, bus_dma_load_crp_buf).

- Most of the existing data-related functions operate on the input
  buffer.  However crypto_copyback always writes to the output buffer
  if a request uses a separate output buffer.

- For the regions in input/output buffers, the following conventions
  are followed:
  - AAD and IV are always present in input only and their
    fields are offsets into the input buffer.
  - payload is always present in both buffers.  If a request uses a
    separate output buffer, it must set a new crp_payload_start_output
    field to the offset of the payload in the output buffer.
  - digest is in the input buffer for verify operations, and in the
    output buffer for compute operations.  crp_digest_start is relative
    to the appropriate buffer.

- Add a crypto buffer cursor abstraction.  This is a more general form
  of some bits in the cryptosoft driver that tried to always use uio's.
  However, compared to the original code, this avoids rewalking the uio
  iovec array for requests with multiple vectors.  It also avoids
  allocate an iovec array for mbufs and populating it by instead walking
  the mbuf chain directly.

- Update the cryptosoft(4) driver to support separate output buffers
  making use of the cursor abstraction.

Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D24545
2020-05-25 22:12:04 +00:00

966 lines
25 KiB
C
Raw Blame History

/* $FreeBSD$ */
/* $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 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;
} else if (sav->alg_auth != 0)
csp.csp_mode = CSP_MODE_ETA;
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;
}
/*
* 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)
{
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;
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), 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(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__));
ESPSTAT_INC(esps_crypto);
crypto_freereq(crp);
error = ENOBUFS;
goto bad;
}
if (esph != NULL) {
crp->crp_op = CRYPTO_OP_VERIFY_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;
}
/* 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_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;
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.
*/
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:
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_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);
Reference in New Issue View Git Blame Copy Permalink