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freebsd-skq/sys/netipsec/xform_ah.c
Conrad Meyer ede2f7731d Correctly handle the padding for IPv6-AH, as specified by RFC4302 
The RFC specifies that under IPv6 the complete AH header must be 64 bit
aligned, and under IPv4, 32 bit aligned. Prior to this change, we (along
with other BSDs and MacOS) had violated this requirement.

This makes it possible to set up IPv6-AH between Linux and BSD, and also
probably between Windows and BSD.

PR:		222684
Reported and tested by:	Jason Mader <jasonmader AT gmail.com>
Obtained from:	NetBSD xform_ah.c 1.105
		(b939fe2483972eb43d71bf990cfb7f26dece7839 NetBSD/src on GH)
		by Maxime Villard
MFC after:	35.2731 hours
Relnotes:	probably (breaks ipv6 compat with older FreeBSD/NetBSD/MacOS)
Sponsored by:	Dell EMC Isilon
2018-06-04 18:51:06 +00:00

1173 lines
29 KiB
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Raw Blame History

/* $FreeBSD$ */
/* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 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 and Niklas Hallqvist.
*
* Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
* Angelos D. Keromytis and Niels Provos.
* Copyright (c) 1999 Niklas Hallqvist.
* 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/mutex.h>
#include <sys/sysctl.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/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>
/*
* Return header size in bytes. The old protocol did not support
* the replay counter; the new protocol always includes the counter.
*/
#define HDRSIZE(sav) \
(((sav)->flags & SADB_X_EXT_OLD) ? \
sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t))
/*
* Return authenticator size in bytes, based on a field in the
* algorithm descriptor.
*/
#define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \
xform_ah_authsize((sav)->tdb_authalgxform))
VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */
VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */
VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat);
VNET_PCPUSTAT_SYSINIT(ahstat);
#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ahstat);
#endif /* VIMAGE */
#ifdef INET
SYSCTL_DECL(_net_inet_ah);
SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, "");
SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, "");
SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat,
ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)");
#endif
static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */
static int ah_input_cb(struct cryptop*);
static int ah_output_cb(struct cryptop*);
int
xform_ah_authsize(const struct auth_hash *esph)
{
int alen;
if (esph == NULL)
return 0;
switch (esph->type) {
case CRYPTO_SHA2_256_HMAC:
case CRYPTO_SHA2_384_HMAC:
case CRYPTO_SHA2_512_HMAC:
alen = esph->hashsize / 2; /* RFC4868 2.3 */
break;
case CRYPTO_AES_128_NIST_GMAC:
case CRYPTO_AES_192_NIST_GMAC:
case CRYPTO_AES_256_NIST_GMAC:
alen = esph->hashsize;
break;
default:
alen = AH_HMAC_HASHLEN;
break;
}
return alen;
}
size_t
ah_hdrsiz(struct secasvar *sav)
{
size_t size;
if (sav != NULL) {
int authsize, rplen, align;
IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform"));
/*XXX not right for null algorithm--does it matter??*/
/* RFC4302: use the correct alignment. */
align = sizeof(uint32_t);
#ifdef INET6
if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) {
align = sizeof(uint64_t);
}
#endif
rplen = HDRSIZE(sav);
authsize = AUTHSIZE(sav);
size = roundup(rplen + authsize, align);
} else {
/* default guess */
size = sizeof (struct ah) + sizeof (u_int32_t) + 16;
}
return size;
}
/*
* NB: public for use by esp_init.
*/
int
ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria)
{
const struct auth_hash *thash;
int keylen;
thash = auth_algorithm_lookup(sav->alg_auth);
if (thash == NULL) {
DPRINTF(("%s: unsupported authentication algorithm %u\n",
__func__, sav->alg_auth));
return EINVAL;
}
/*
* Verify the replay state block allocation is consistent with
* the protocol type. We check here so we can make assumptions
* later during protocol processing.
*/
/* NB: replay state is setup elsewhere (sigh) */
if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) {
DPRINTF(("%s: replay state block inconsistency, "
"%s algorithm %s replay state\n", __func__,
(sav->flags & SADB_X_EXT_OLD) ? "old" : "new",
sav->replay == NULL ? "without" : "with"));
return EINVAL;
}
if (sav->key_auth == NULL) {
DPRINTF(("%s: no authentication key for %s algorithm\n",
__func__, thash->name));
return EINVAL;
}
keylen = _KEYLEN(sav->key_auth);
if (keylen > thash->keysize && thash->keysize != 0) {
DPRINTF(("%s: invalid keylength %d, algorithm %s requires "
"keysize less than %d\n", __func__,
keylen, thash->name, thash->keysize));
return EINVAL;
}
sav->tdb_xform = xsp;
sav->tdb_authalgxform = thash;
/* Initialize crypto session. */
bzero(cria, sizeof (*cria));
cria->cri_alg = sav->tdb_authalgxform->type;
cria->cri_klen = _KEYBITS(sav->key_auth);
cria->cri_key = sav->key_auth->key_data;
cria->cri_mlen = AUTHSIZE(sav);
return 0;
}
/*
* ah_init() is called when an SPI is being set up.
*/
static int
ah_init(struct secasvar *sav, struct xformsw *xsp)
{
struct cryptoini cria;
int error;
error = ah_init0(sav, xsp, &cria);
return error ? error :
crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support);
}
/*
* Paranoia.
*
* NB: public for use by esp_zeroize (XXX).
*/
int
ah_zeroize(struct secasvar *sav)
{
int err;
if (sav->key_auth)
bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth));
err = crypto_freesession(sav->tdb_cryptoid);
sav->tdb_cryptoid = 0;
sav->tdb_authalgxform = NULL;
sav->tdb_xform = NULL;
return err;
}
/*
* Massage IPv4/IPv6 headers for AH processing.
*/
static int
ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out)
{
struct mbuf *m = *m0;
unsigned char *ptr;
int off, count;
#ifdef INET
struct ip *ip;
#endif /* INET */
#ifdef INET6
struct ip6_ext *ip6e;
struct ip6_hdr ip6;
int ad, alloc, nxt, noff;
#endif /* INET6 */
switch (proto) {
#ifdef INET
case AF_INET:
/*
* This is the least painful way of dealing with IPv4 header
* and option processing -- just make sure they're in
* contiguous memory.
*/
*m0 = m = m_pullup(m, skip);
if (m == NULL) {
DPRINTF(("%s: m_pullup failed\n", __func__));
return ENOBUFS;
}
/* Fix the IP header */
ip = mtod(m, struct ip *);
if (V_ah_cleartos)
ip->ip_tos = 0;
ip->ip_ttl = 0;
ip->ip_sum = 0;
if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK)
ip->ip_off &= htons(IP_DF);
else
ip->ip_off = htons(0);
ptr = mtod(m, unsigned char *);
/* IPv4 option processing */
for (off = sizeof(struct ip); off < skip;) {
if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP ||
off + 1 < skip)
;
else {
DPRINTF(("%s: illegal IPv4 option length for "
"option %d\n", __func__, ptr[off]));
m_freem(m);
return EINVAL;
}
switch (ptr[off]) {
case IPOPT_EOL:
off = skip; /* End the loop. */
break;
case IPOPT_NOP:
off++;
break;
case IPOPT_SECURITY: /* 0x82 */
case 0x85: /* Extended security. */
case 0x86: /* Commercial security. */
case 0x94: /* Router alert */
case 0x95: /* RFC1770 */
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
off += ptr[off + 1];
break;
case IPOPT_LSRR:
case IPOPT_SSRR:
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
/*
* On output, if we have either of the
* source routing options, we should
* swap the destination address of the
* IP header with the last address
* specified in the option, as that is
* what the destination's IP header
* will look like.
*/
if (out)
bcopy(ptr + off + ptr[off + 1] -
sizeof(struct in_addr),
&(ip->ip_dst), sizeof(struct in_addr));
/* Fall through */
default:
/* Sanity check for option length. */
if (ptr[off + 1] < 2) {
DPRINTF(("%s: illegal IPv4 option "
"length for option %d\n",
__func__, ptr[off]));
m_freem(m);
return EINVAL;
}
/* Zeroize all other options. */
count = ptr[off + 1];
bcopy(ipseczeroes, ptr + off, count);
off += count;
break;
}
/* Sanity check. */
if (off > skip) {
DPRINTF(("%s: malformed IPv4 options header\n",
__func__));
m_freem(m);
return EINVAL;
}
}
break;
#endif /* INET */
#ifdef INET6
case AF_INET6: /* Ugly... */
/* Copy and "cook" the IPv6 header. */
m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6);
/* We don't do IPv6 Jumbograms. */
if (ip6.ip6_plen == 0) {
DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__));
m_freem(m);
return EMSGSIZE;
}
ip6.ip6_flow = 0;
ip6.ip6_hlim = 0;
ip6.ip6_vfc &= ~IPV6_VERSION_MASK;
ip6.ip6_vfc |= IPV6_VERSION;
/* Scoped address handling. */
if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src))
ip6.ip6_src.s6_addr16[1] = 0;
if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst))
ip6.ip6_dst.s6_addr16[1] = 0;
/* Done with IPv6 header. */
m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6);
/* Let's deal with the remaining headers (if any). */
if (skip - sizeof(struct ip6_hdr) > 0) {
if (m->m_len <= skip) {
ptr = (unsigned char *) malloc(
skip - sizeof(struct ip6_hdr),
M_XDATA, M_NOWAIT);
if (ptr == NULL) {
DPRINTF(("%s: failed to allocate memory"
"for IPv6 headers\n",__func__));
m_freem(m);
return ENOBUFS;
}
/*
* Copy all the protocol headers after
* the IPv6 header.
*/
m_copydata(m, sizeof(struct ip6_hdr),
skip - sizeof(struct ip6_hdr), ptr);
alloc = 1;
} else {
/* No need to allocate memory. */
ptr = mtod(m, unsigned char *) +
sizeof(struct ip6_hdr);
alloc = 0;
}
} else
break;
nxt = ip6.ip6_nxt & 0xff; /* Next header type. */
for (off = 0; off < skip - sizeof(struct ip6_hdr);)
switch (nxt) {
case IPPROTO_HOPOPTS:
case IPPROTO_DSTOPTS:
ip6e = (struct ip6_ext *)(ptr + off);
noff = off + ((ip6e->ip6e_len + 1) << 3);
/* Sanity check. */
if (noff > skip - sizeof(struct ip6_hdr))
goto error6;
/*
* Zero out mutable options.
*/
for (count = off + sizeof(struct ip6_ext);
count < noff;) {
if (ptr[count] == IP6OPT_PAD1) {
count++;
continue; /* Skip padding. */
}
ad = ptr[count + 1] + 2;
if (count + ad > noff)
goto error6;
if (ptr[count] & IP6OPT_MUTABLE)
memset(ptr + count, 0, ad);
count += ad;
}
if (count != noff)
goto error6;
/* Advance. */
off += ((ip6e->ip6e_len + 1) << 3);
nxt = ip6e->ip6e_nxt;
break;
case IPPROTO_ROUTING:
/*
* Always include routing headers in
* computation.
*/
ip6e = (struct ip6_ext *) (ptr + off);
off += ((ip6e->ip6e_len + 1) << 3);
nxt = ip6e->ip6e_nxt;
break;
default:
DPRINTF(("%s: unexpected IPv6 header type %d",
__func__, off));
error6:
if (alloc)
free(ptr, M_XDATA);
m_freem(m);
return EINVAL;
}
/* Copyback and free, if we allocated. */
if (alloc) {
m_copyback(m, sizeof(struct ip6_hdr),
skip - sizeof(struct ip6_hdr), ptr);
free(ptr, M_XDATA);
}
break;
#endif /* INET6 */
}
return 0;
}
/*
* ah_input() gets called to verify that an input packet
* passes authentication.
*/
static int
ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
{
IPSEC_DEBUG_DECLARE(char buf[128]);
const struct auth_hash *ahx;
struct cryptodesc *crda;
struct cryptop *crp;
struct xform_data *xd;
struct newah *ah;
uint64_t cryptoid;
int hl, rplen, authsize, ahsize, error;
IPSEC_ASSERT(sav != NULL, ("null SA"));
IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key"));
IPSEC_ASSERT(sav->tdb_authalgxform != NULL,
("null authentication xform"));
/* Figure out header size. */
rplen = HDRSIZE(sav);
/* XXX don't pullup, just copy header */
IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen);
if (ah == NULL) {
DPRINTF(("ah_input: cannot pullup header\n"));
AHSTAT_INC(ahs_hdrops); /*XXX*/
error = ENOBUFS;
goto bad;
}
/* Check replay window, if applicable. */
SECASVAR_LOCK(sav);
if (sav->replay != NULL && sav->replay->wsize != 0 &&
ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) {
SECASVAR_UNLOCK(sav);
AHSTAT_INC(ahs_replay);
DPRINTF(("%s: packet replay failure: %s\n", __func__,
ipsec_sa2str(sav, buf, sizeof(buf))));
error = EACCES;
goto bad;
}
cryptoid = sav->tdb_cryptoid;
SECASVAR_UNLOCK(sav);
/* Verify AH header length. */
hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t));
ahx = sav->tdb_authalgxform;
authsize = AUTHSIZE(sav);
ahsize = ah_hdrsiz(sav);
if (hl != ahsize) {
DPRINTF(("%s: bad authenticator length %u (expecting %lu)"
" for packet in SA %s/%08lx\n", __func__, hl,
(u_long)ahsize,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_badauthl);
error = EACCES;
goto bad;
}
if (skip + ahsize > m->m_pkthdr.len) {
DPRINTF(("%s: bad mbuf length %u (expecting %lu)"
" for packet in SA %s/%08lx\n", __func__,
m->m_pkthdr.len, (u_long)(skip + ahsize),
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_badauthl);
error = EACCES;
goto bad;
}
AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl);
/* Get crypto descriptors. */
crp = crypto_getreq(1);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptor\n",
__func__));
AHSTAT_INC(ahs_crypto);
error = ENOBUFS;
goto bad;
}
crda = crp->crp_desc;
IPSEC_ASSERT(crda != NULL, ("null crypto descriptor"));
crda->crd_skip = 0;
crda->crd_len = m->m_pkthdr.len;
crda->crd_inject = skip + rplen;
/* Authentication operation. */
crda->crd_alg = ahx->type;
crda->crd_klen = _KEYBITS(sav->key_auth);
crda->crd_key = sav->key_auth->key_data;
/* Allocate IPsec-specific opaque crypto info. */
xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA,
M_NOWAIT | M_ZERO);
if (xd == NULL) {
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
AHSTAT_INC(ahs_crypto);
crypto_freereq(crp);
error = ENOBUFS;
goto bad;
}
/*
* Save the authenticator, the skipped portion of the packet,
* and the AH header.
*/
m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1));
/* Zeroize the authenticator on the packet. */
m_copyback(m, skip + rplen, authsize, ipseczeroes);
/* Save ah_nxt, since ah pointer can become invalid after "massage" */
hl = ah->ah_nxt;
/* "Massage" the packet headers for crypto processing. */
error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
skip, ahx->type, 0);
if (error != 0) {
/* NB: mbuf is free'd by ah_massage_headers */
AHSTAT_INC(ahs_hdrops);
free(xd, M_XDATA);
crypto_freereq(crp);
key_freesav(&sav);
return (error);
}
/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
if (V_async_crypto)
crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = ah_input_cb;
crp->crp_sid = cryptoid;
crp->crp_opaque = (caddr_t) xd;
/* These are passed as-is to the callback. */
xd->sav = sav;
xd->nxt = hl;
xd->protoff = protoff;
xd->skip = skip;
xd->cryptoid = cryptoid;
xd->vnet = curvnet;
return (crypto_dispatch(crp));
bad:
m_freem(m);
key_freesav(&sav);
return (error);
}
/*
* AH input callback from the crypto driver.
*/
static int
ah_input_cb(struct cryptop *crp)
{
IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
unsigned char calc[AH_ALEN_MAX];
struct mbuf *m;
struct xform_data *xd;
struct secasvar *sav;
struct secasindex *saidx;
caddr_t ptr;
uint64_t cryptoid;
int authsize, rplen, ahsize, error, skip, protoff;
uint8_t nxt;
m = (struct mbuf *) crp->crp_buf;
xd = (struct xform_data *) crp->crp_opaque;
CURVNET_SET(xd->vnet);
sav = xd->sav;
skip = xd->skip;
nxt = xd->nxt;
protoff = xd->protoff;
cryptoid = xd->cryptoid;
saidx = &sav->sah->saidx;
IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
saidx->dst.sa.sa_family == AF_INET6,
("unexpected protocol family %u", saidx->dst.sa.sa_family));
/* 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;
CURVNET_RESTORE();
return (crypto_dispatch(crp));
}
AHSTAT_INC(ahs_noxform);
DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
error = crp->crp_etype;
goto bad;
} else {
AHSTAT_INC(ahs_hist[sav->alg_auth]);
crypto_freereq(crp); /* No longer needed. */
crp = NULL;
}
/* Shouldn't happen... */
if (m == NULL) {
AHSTAT_INC(ahs_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
/* Figure out header size. */
rplen = HDRSIZE(sav);
authsize = AUTHSIZE(sav);
ahsize = ah_hdrsiz(sav);
/* Copy authenticator off the packet. */
m_copydata(m, skip + rplen, authsize, calc);
/* Verify authenticator. */
ptr = (caddr_t) (xd + 1);
if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) {
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)));
AHSTAT_INC(ahs_badauth);
error = EACCES;
goto bad;
}
/* Fix the Next Protocol field. */
((uint8_t *) ptr)[protoff] = nxt;
/* Copyback the saved (uncooked) network headers. */
m_copyback(m, 0, skip, ptr);
free(xd, M_XDATA), xd = NULL; /* No longer needed */
/*
* Header is now authenticated.
*/
m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM;
/*
* Update replay sequence number, if appropriate.
*/
if (sav->replay) {
u_int32_t seq;
m_copydata(m, skip + offsetof(struct newah, ah_seq),
sizeof (seq), (caddr_t) &seq);
SECASVAR_LOCK(sav);
if (ipsec_updatereplay(ntohl(seq), sav)) {
SECASVAR_UNLOCK(sav);
AHSTAT_INC(ahs_replay);
error = EACCES;
goto bad;
}
SECASVAR_UNLOCK(sav);
}
/*
* Remove the AH header and authenticator from the mbuf.
*/
error = m_striphdr(m, skip, ahsize);
if (error) {
DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__,
ipsec_address(&saidx->dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops);
goto bad;
}
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)
key_freesav(&sav);
if (m != NULL)
m_freem(m);
if (xd != NULL)
free(xd, M_XDATA);
if (crp != NULL)
crypto_freereq(crp);
return error;
}
/*
* AH output routine, called by ipsec[46]_perform_request().
*/
static int
ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
u_int idx, int skip, int protoff)
{
IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
const struct auth_hash *ahx;
struct cryptodesc *crda;
struct xform_data *xd;
struct mbuf *mi;
struct cryptop *crp;
struct newah *ah;
uint64_t cryptoid;
uint16_t iplen;
int error, rplen, authsize, ahsize, maxpacketsize, roff;
uint8_t prot;
IPSEC_ASSERT(sav != NULL, ("null SA"));
ahx = sav->tdb_authalgxform;
IPSEC_ASSERT(ahx != NULL, ("null authentication xform"));
AHSTAT_INC(ahs_output);
/* Figure out header size. */
rplen = HDRSIZE(sav);
authsize = AUTHSIZE(sav);
ahsize = ah_hdrsiz(sav);
/* Check for maximum packet size violations. */
switch (sav->sah->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 %u, "
"SA %s/%08lx\n", __func__,
sav->sah->saidx.dst.sa.sa_family,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_nopf);
error = EPFNOSUPPORT;
goto bad;
}
if (ahsize + m->m_pkthdr.len > maxpacketsize) {
DPRINTF(("%s: packet in SA %s/%08lx got too big "
"(len %u, max len %u)\n", __func__,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi),
ahsize + m->m_pkthdr.len, maxpacketsize));
AHSTAT_INC(ahs_toobig);
error = EMSGSIZE;
goto bad;
}
/* Update the counters. */
AHSTAT_ADD(ahs_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(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops);
error = ENOBUFS;
goto bad;
}
/* Inject AH header. */
mi = m_makespace(m, skip, ahsize, &roff);
if (mi == NULL) {
DPRINTF(("%s: failed to inject %u byte AH header for SA "
"%s/%08lx\n", __func__, ahsize,
ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
(u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */
error = ENOBUFS;
goto bad;
}
/*
* The AH header is guaranteed by m_makespace() to be in
* contiguous memory, at roff bytes offset into the returned mbuf.
*/
ah = (struct newah *)(mtod(mi, caddr_t) + roff);
/* Initialize the AH header. */
m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt);
ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t);
ah->ah_reserve = 0;
ah->ah_spi = sav->spi;
/* Zeroize authenticator. */
m_copyback(m, skip + rplen, authsize, ipseczeroes);
/* Zeroize padding */
m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize),
ipseczeroes);
/* Insert packet replay counter, as requested. */
SECASVAR_LOCK(sav);
if (sav->replay) {
if (sav->replay->count == ~0 &&
(sav->flags & SADB_X_EXT_CYCSEQ) == 0) {
SECASVAR_UNLOCK(sav);
DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n",
__func__, ipsec_address(&sav->sah->saidx.dst, buf,
sizeof(buf)), (u_long) ntohl(sav->spi)));
AHSTAT_INC(ahs_wrap);
error = EACCES;
goto bad;
}
#ifdef REGRESSION
/* Emulate replay attack when ipsec_replay is TRUE. */
if (!V_ipsec_replay)
#endif
sav->replay->count++;
ah->ah_seq = htonl(sav->replay->count);
}
cryptoid = sav->tdb_cryptoid;
SECASVAR_UNLOCK(sav);
/* Get crypto descriptors. */
crp = crypto_getreq(1);
if (crp == NULL) {
DPRINTF(("%s: failed to acquire crypto descriptors\n",
__func__));
AHSTAT_INC(ahs_crypto);
error = ENOBUFS;
goto bad;
}
crda = crp->crp_desc;
crda->crd_skip = 0;
crda->crd_inject = skip + rplen;
crda->crd_len = m->m_pkthdr.len;
/* Authentication operation. */
crda->crd_alg = ahx->type;
crda->crd_key = sav->key_auth->key_data;
crda->crd_klen = _KEYBITS(sav->key_auth);
/* Allocate IPsec-specific opaque crypto info. */
xd = malloc(sizeof(struct xform_data) + skip, M_XDATA,
M_NOWAIT | M_ZERO);
if (xd == NULL) {
crypto_freereq(crp);
DPRINTF(("%s: failed to allocate xform_data\n", __func__));
AHSTAT_INC(ahs_crypto);
error = ENOBUFS;
goto bad;
}
/* Save the skipped portion of the packet. */
m_copydata(m, 0, skip, (caddr_t) (xd + 1));
/*
* Fix IP header length on the header used for
* authentication. We don't need to fix the original
* header length as it will be fixed by our caller.
*/
switch (sav->sah->saidx.dst.sa.sa_family) {
#ifdef INET
case AF_INET:
bcopy(((caddr_t)(xd + 1)) +
offsetof(struct ip, ip_len),
(caddr_t) &iplen, sizeof(u_int16_t));
iplen = htons(ntohs(iplen) + ahsize);
m_copyback(m, offsetof(struct ip, ip_len),
sizeof(u_int16_t), (caddr_t) &iplen);
break;
#endif /* INET */
#ifdef INET6
case AF_INET6:
bcopy(((caddr_t)(xd + 1)) +
offsetof(struct ip6_hdr, ip6_plen),
(caddr_t) &iplen, sizeof(uint16_t));
iplen = htons(ntohs(iplen) + ahsize);
m_copyback(m, offsetof(struct ip6_hdr, ip6_plen),
sizeof(uint16_t), (caddr_t) &iplen);
break;
#endif /* INET6 */
}
/* Fix the Next Header field in saved header. */
((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH;
/* Update the Next Protocol field in the IP header. */
prot = IPPROTO_AH;
m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot);
/* "Massage" the packet headers for crypto processing. */
error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family,
skip, ahx->type, 1);
if (error != 0) {
m = NULL; /* mbuf was free'd by ah_massage_headers. */
free(xd, M_XDATA);
crypto_freereq(crp);
goto bad;
}
/* Crypto operation descriptor. */
crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
if (V_async_crypto)
crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
crp->crp_buf = (caddr_t) m;
crp->crp_callback = ah_output_cb;
crp->crp_sid = cryptoid;
crp->crp_opaque = (caddr_t) xd;
/* These are passed as-is to the callback. */
xd->sp = sp;
xd->sav = sav;
xd->skip = skip;
xd->idx = idx;
xd->cryptoid = cryptoid;
xd->vnet = curvnet;
return crypto_dispatch(crp);
bad:
if (m)
m_freem(m);
key_freesav(&sav);
key_freesp(&sp);
return (error);
}
/*
* AH output callback from the crypto driver.
*/
static int
ah_output_cb(struct cryptop *crp)
{
struct xform_data *xd;
struct secpolicy *sp;
struct secasvar *sav;
struct mbuf *m;
uint64_t cryptoid;
caddr_t ptr;
u_int idx;
int skip, error;
m = (struct mbuf *) crp->crp_buf;
xd = (struct xform_data *) crp->crp_opaque;
CURVNET_SET(xd->vnet);
sp = xd->sp;
sav = xd->sav;
skip = xd->skip;
idx = xd->idx;
cryptoid = xd->cryptoid;
ptr = (caddr_t) (xd + 1);
/* 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;
CURVNET_RESTORE();
return (crypto_dispatch(crp));
}
AHSTAT_INC(ahs_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) {
AHSTAT_INC(ahs_crypto);
DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
error = EINVAL;
goto bad;
}
/*
* Copy original headers (with the new protocol number) back
* in place.
*/
m_copyback(m, 0, skip, ptr);
free(xd, M_XDATA);
crypto_freereq(crp);
AHSTAT_INC(ahs_hist[sav->alg_auth]);
#ifdef REGRESSION
/* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
if (V_ipsec_integrity) {
int alen;
/*
* Corrupt HMAC if we want to test integrity verification of
* the other side.
*/
alen = AUTHSIZE(sav);
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 ah_xformsw = {
.xf_type = XF_AH,
.xf_name = "IPsec AH",
.xf_init = ah_init,
.xf_zeroize = ah_zeroize,
.xf_input = ah_input,
.xf_output = ah_output,
};
SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
xform_attach, &ah_xformsw);
SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
xform_detach, &ah_xformsw);
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