/* $FreeBSD$ */ /* $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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef INET6 #include #include #include #endif #include #include #include /* * 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(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; } /* * NB: this is public for use by the PF_KEY support. */ struct auth_hash * ah_algorithm_lookup(int alg) { if (alg > SADB_AALG_MAX) return NULL; switch (alg) { case SADB_X_AALG_NULL: return &auth_hash_null; case SADB_AALG_MD5HMAC: return &auth_hash_hmac_md5; case SADB_AALG_SHA1HMAC: return &auth_hash_hmac_sha1; case SADB_X_AALG_RIPEMD160HMAC: return &auth_hash_hmac_ripemd_160; case SADB_X_AALG_MD5: return &auth_hash_key_md5; case SADB_X_AALG_SHA: return &auth_hash_key_sha1; case SADB_X_AALG_SHA2_256: return &auth_hash_hmac_sha2_256; case SADB_X_AALG_SHA2_384: return &auth_hash_hmac_sha2_384; case SADB_X_AALG_SHA2_512: return &auth_hash_hmac_sha2_512; case SADB_X_AALG_AES128GMAC: return &auth_hash_nist_gmac_aes_128; case SADB_X_AALG_AES192GMAC: return &auth_hash_nist_gmac_aes_192; case SADB_X_AALG_AES256GMAC: return &auth_hash_nist_gmac_aes_256; } return NULL; } size_t ah_hdrsiz(struct secasvar *sav) { size_t size; if (sav != NULL) { int authsize; IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); /*XXX not right for null algorithm--does it matter??*/ authsize = AUTHSIZE(sav); size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); } 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) { struct auth_hash *thash; int keylen; thash = ah_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 %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) { char buf[128]; struct auth_hash *ahx; struct tdb_crypto *tc; struct newah *ah; int hl, rplen, authsize, error; struct cryptodesc *crda; struct cryptop *crp; 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*/ m_freem(m); return ENOBUFS; } /* Check replay window, if applicable. */ if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { AHSTAT_INC(ahs_replay); DPRINTF(("%s: packet replay failure: %s\n", __func__, ipsec_logsastr(sav, buf, sizeof(buf)))); m_freem(m); return ENOBUFS; } /* Verify AH header length. */ hl = ah->ah_len * sizeof (u_int32_t); ahx = sav->tdb_authalgxform; authsize = AUTHSIZE(sav); if (hl != authsize + rplen - sizeof (struct ah)) { DPRINTF(("%s: bad authenticator length %u (expecting %lu)" " for packet in SA %s/%08lx\n", __func__, hl, (u_long) (authsize + rplen - sizeof (struct ah)), ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi))); AHSTAT_INC(ahs_badauthl); m_freem(m); return EACCES; } 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); m_freem(m); return ENOBUFS; } 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. */ tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + skip + rplen + authsize, M_XDATA, M_NOWAIT | M_ZERO); if (tc == NULL) { DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); AHSTAT_INC(ahs_crypto); crypto_freereq(crp); m_freem(m); return ENOBUFS; } /* * Save the authenticator, the skipped portion of the packet, * and the AH header. */ m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); /* Zeroize the authenticator on the packet. */ m_copyback(m, skip + rplen, authsize, ipseczeroes); /* "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(tc, M_XDATA); crypto_freereq(crp); return (error); } /* 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 = ah_input_cb; crp->crp_sid = sav->tdb_cryptoid; crp->crp_opaque = (caddr_t) tc; /* These are passed as-is to the callback. */ tc->tc_spi = sav->spi; tc->tc_dst = sav->sah->saidx.dst; tc->tc_proto = sav->sah->saidx.proto; tc->tc_nxt = ah->ah_nxt; tc->tc_protoff = protoff; tc->tc_skip = skip; KEY_ADDREFSA(sav); tc->tc_sav = sav; return (crypto_dispatch(crp)); } /* * AH input callback from the crypto driver. */ static int ah_input_cb(struct cryptop *crp) { char buf[INET6_ADDRSTRLEN]; int rplen, error, skip, protoff; unsigned char calc[AH_ALEN_MAX]; struct mbuf *m; struct cryptodesc *crd; struct auth_hash *ahx; struct tdb_crypto *tc; struct secasvar *sav; struct secasindex *saidx; u_int8_t nxt; caddr_t ptr; int authsize; crd = crp->crp_desc; tc = (struct tdb_crypto *) crp->crp_opaque; IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); skip = tc->tc_skip; nxt = tc->tc_nxt; protoff = tc->tc_protoff; m = (struct mbuf *) crp->crp_buf; sav = tc->tc_sav; IPSEC_ASSERT(sav != NULL, ("null SA!")); 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)); ahx = (struct auth_hash *) sav->tdb_authalgxform; /* Check for crypto errors. */ if (crp->crp_etype) { if (sav->tdb_cryptoid != 0) sav->tdb_cryptoid = crp->crp_sid; if (crp->crp_etype == EAGAIN) 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); /* Copy authenticator off the packet. */ m_copydata(m, skip + rplen, authsize, calc); /* Verify authenticator. */ ptr = (caddr_t) (tc + 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. */ ((u_int8_t *) ptr)[protoff] = nxt; /* Copyback the saved (uncooked) network headers. */ m_copyback(m, 0, skip, ptr); free(tc, M_XDATA), tc = 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); if (ipsec_updatereplay(ntohl(seq), sav)) { AHSTAT_INC(ahs_replay); error = ENOBUFS; /*XXX as above*/ goto bad; } } /* * Remove the AH header and authenticator from the mbuf. */ error = m_striphdr(m, skip, rplen + authsize); 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); } KEY_FREESAV(&sav); return error; bad: if (sav) KEY_FREESAV(&sav); if (m != NULL) m_freem(m); if (tc != NULL) free(tc, M_XDATA); if (crp != NULL) crypto_freereq(crp); return error; } /* * AH output routine, called by ipsec[46]_process_packet(). */ static int ah_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp, int skip, int protoff) { char buf[INET6_ADDRSTRLEN]; struct secasvar *sav; struct auth_hash *ahx; struct cryptodesc *crda; struct tdb_crypto *tc; struct mbuf *mi; struct cryptop *crp; u_int16_t iplen; int error, rplen, authsize, maxpacketsize, roff; u_int8_t prot; struct newah *ah; sav = isr->sav; 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); /* 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; } authsize = AUTHSIZE(sav); if (rplen + authsize + 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), rplen + authsize + 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, rplen + authsize, &roff); if (mi == NULL) { DPRINTF(("%s: failed to inject %u byte AH header for SA " "%s/%08lx\n", __func__, rplen + authsize, 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 = (rplen + authsize - 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); /* Insert packet replay counter, as requested. */ if (sav->replay) { if (sav->replay->count == ~0 && (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 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 = EINVAL; 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); } /* 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. */ tc = (struct tdb_crypto *) malloc( sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); if (tc == NULL) { crypto_freereq(crp); DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); AHSTAT_INC(ahs_crypto); error = ENOBUFS; goto bad; } /* Save the skipped portion of the packet. */ m_copydata(m, 0, skip, (caddr_t) (tc + 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)(tc + 1)) + offsetof(struct ip, ip_len), (caddr_t) &iplen, sizeof(u_int16_t)); iplen = htons(ntohs(iplen) + rplen + authsize); 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)(tc + 1)) + offsetof(struct ip6_hdr, ip6_plen), (caddr_t) &iplen, sizeof(u_int16_t)); iplen = htons(ntohs(iplen) + rplen + authsize); m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), sizeof(u_int16_t), (caddr_t) &iplen); break; #endif /* INET6 */ } /* Fix the Next Header field in saved header. */ ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; /* Update the Next Protocol field in the IP header. */ prot = IPPROTO_AH; m_copyback(m, protoff, sizeof(u_int8_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(tc, 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; crp->crp_buf = (caddr_t) m; crp->crp_callback = ah_output_cb; crp->crp_sid = sav->tdb_cryptoid; crp->crp_opaque = (caddr_t) tc; /* These are passed as-is to the callback. */ key_addref(isr->sp); tc->tc_isr = isr; KEY_ADDREFSA(sav); tc->tc_sav = sav; tc->tc_spi = sav->spi; tc->tc_dst = sav->sah->saidx.dst; tc->tc_proto = sav->sah->saidx.proto; tc->tc_skip = skip; tc->tc_protoff = protoff; return crypto_dispatch(crp); bad: if (m) m_freem(m); return (error); } /* * AH output callback from the crypto driver. */ static int ah_output_cb(struct cryptop *crp) { int skip, protoff, error; struct tdb_crypto *tc; struct ipsecrequest *isr; struct secasvar *sav; struct mbuf *m; caddr_t ptr; tc = (struct tdb_crypto *) crp->crp_opaque; IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); skip = tc->tc_skip; protoff = tc->tc_protoff; ptr = (caddr_t) (tc + 1); m = (struct mbuf *) crp->crp_buf; isr = tc->tc_isr; IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp")); IPSECREQUEST_LOCK(isr); sav = tc->tc_sav; /* With the isr lock released SA pointer can be updated. */ if (sav != isr->sav) { AHSTAT_INC(ahs_notdb); DPRINTF(("%s: SA expired while in crypto\n", __func__)); error = ENOBUFS; /*XXX*/ goto bad; } /* Check for crypto errors. */ if (crp->crp_etype) { if (sav->tdb_cryptoid != 0) sav->tdb_cryptoid = crp->crp_sid; if (crp->crp_etype == EAGAIN) { IPSECREQUEST_UNLOCK(isr); return (crypto_dispatch(crp)); } AHSTAT_INC(ahs_noxform); DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); error = crp->crp_etype; 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; } AHSTAT_INC(ahs_hist[sav->alg_auth]); /* * Copy original headers (with the new protocol number) back * in place. */ m_copyback(m, 0, skip, ptr); /* No longer needed. */ free(tc, M_XDATA); crypto_freereq(crp); #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, isr); KEY_FREESAV(&sav); IPSECREQUEST_UNLOCK(isr); KEY_FREESP(&isr->sp); return (error); bad: if (sav) KEY_FREESAV(&sav); IPSECREQUEST_UNLOCK(isr); KEY_FREESP(&isr->sp); if (m) m_freem(m); free(tc, M_XDATA); crypto_freereq(crp); return (error); } static struct xformsw ah_xformsw = { XF_AH, XFT_AUTH, "IPsec AH", ah_init, ah_zeroize, ah_input, ah_output, }; static void ah_attach(void) { xform_register(&ah_xformsw); } SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);