/* $NetBSD: xform_ah.c,v 1.114 2022/05/22 11:40:29 riastradh Exp $ */ /* $FreeBSD: xform_ah.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $ */ /* $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 __KERNEL_RCSID(0, "$NetBSD: xform_ah.c,v 1.114 2022/05/22 11:40:29 riastradh Exp $"); #if defined(_KERNEL_OPT) #include "opt_inet.h" #include "opt_ipsec.h" #endif #include #include #include #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(uint32_t)) /* * Return authenticator size in bytes. The old protocol is known * to use a fixed 16-byte authenticator. The new algorithm gets * this size from the xform but is (currently) always 12. */ #define AUTHSIZE(sav) \ ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize) percpu_t *ahstat_percpu; int ah_enable = 1; /* control flow of packets with AH */ int ip4_ah_cleartos = 1; /* clear ip_tos when doing AH calc */ static const char ipseczeroes[256]; int ah_max_authsize; /* max authsize over all algorithms */ static void ah_input_cb(struct cryptop *); static void ah_output_cb(struct cryptop *); const uint8_t ah_stats[256] = { SADB_AALG_STATS_INIT }; static pool_cache_t ah_tdb_crypto_pool_cache; static size_t ah_pool_item_size; /* * NB: this is public for use by the PF_KEY support. */ const struct auth_hash * ah_algorithm_lookup(int alg) { switch (alg) { case SADB_X_AALG_NULL: return &auth_hash_null; case SADB_AALG_MD5HMAC: return &auth_hash_hmac_md5_96; case SADB_AALG_SHA1HMAC: return &auth_hash_hmac_sha1_96; case SADB_X_AALG_RIPEMD160HMAC: return &auth_hash_hmac_ripemd_160_96; 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_AES_XCBC_MAC: return &auth_hash_aes_xcbc_mac_96; } return NULL; } size_t ah_authsiz(const struct secasvar *sav) { size_t size; if (sav == NULL) { return ah_max_authsize; } size = AUTHSIZE(sav); return roundup(size, sizeof(uint32_t)); } size_t ah_hdrsiz(const struct secasvar *sav) { size_t size; if (sav != NULL) { int authsize, rplen, align; KASSERT(sav->tdb_authalgxform != NULL); /*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(uint32_t) + ah_max_authsize; } return size; } /* * NB: public for use by esp_init. */ int ah_init0(struct secasvar *sav, const struct xformsw *xsp, struct cryptoini *cria) { const struct auth_hash *thash; int keylen; thash = ah_algorithm_lookup(sav->alg_auth); if (thash == NULL) { DPRINTF("unsupported authentication algorithm %u\n", 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("replay state block inconsistency, " "%s algorithm %s replay state\n", (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", sav->replay == NULL ? "without" : "with"); return EINVAL; } if (sav->key_auth == NULL) { DPRINTF("no authentication key for %s algorithm\n", thash->name); return EINVAL; } keylen = _KEYLEN(sav->key_auth); if (keylen != thash->keysize && thash->keysize != 0) { DPRINTF("invalid keylength %d, algorithm %s requires " "keysize %d\n", keylen, thash->name, thash->keysize); return EINVAL; } sav->tdb_xform = xsp; sav->tdb_authalgxform = thash; /* Initialize crypto session. */ memset(cria, 0, sizeof(*cria)); cria->cri_alg = sav->tdb_authalgxform->type; cria->cri_klen = _KEYBITS(sav->key_auth); cria->cri_key = _KEYBUF(sav->key_auth); return 0; } /* * ah_init() is called when an SPI is being set up. */ static int ah_init(struct secasvar *sav, const struct xformsw *xsp) { struct cryptoini cria; int error; error = ah_init0(sav, xsp, &cria); if (!error) error = crypto_newsession(&sav->tdb_cryptoid, &cria, crypto_support); return error; } /* * Paranoia. * * NB: public for use by esp_zeroize (XXX). */ void ah_zeroize(struct secasvar *sav) { if (sav->key_auth) { explicit_memset(_KEYBUF(sav->key_auth), 0, _KEYLEN(sav->key_auth)); } crypto_freesession(sav->tdb_cryptoid); sav->tdb_cryptoid = 0; sav->tdb_authalgxform = NULL; sav->tdb_xform = NULL; } /* * 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, optlen; #ifdef INET struct ip *ip; #endif #ifdef INET6 int count, ip6optlen; struct ip6_ext *ip6e; struct ip6_hdr ip6; int alloc, nxt; #endif 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("m_pullup failed\n"); return ENOBUFS; } /* Fix the IP header */ ip = mtod(m, struct ip *); if (ip4_ah_cleartos) ip->ip_tos = 0; ip->ip_ttl = 0; ip->ip_sum = 0; ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask); if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) ip->ip_off &= htons(IP_DF); else ip->ip_off = 0; ptr = mtod(m, unsigned char *); /* IPv4 option processing */ for (off = sizeof(struct ip); off < skip;) { if (ptr[off] == IPOPT_EOL) { break; } else if (ptr[off] == IPOPT_NOP) { optlen = 1; } else if (off + 1 < skip) { optlen = ptr[off + 1]; if (optlen < 2 || off + optlen > skip) { m_freem(m); return EINVAL; } } else { m_freem(m); return EINVAL; } switch (ptr[off]) { case IPOPT_NOP: case IPOPT_SECURITY: case 0x85: /* Extended security. */ case 0x86: /* Commercial security. */ case 0x94: /* Router alert */ case 0x95: /* RFC1770 */ break; case IPOPT_LSRR: case IPOPT_SSRR: /* * 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) memcpy(&ip->ip_dst, ptr + off + optlen - sizeof(struct in_addr), sizeof(struct in_addr)); /* FALLTHROUGH */ default: /* Zeroize all other options. */ memset(ptr + off, 0, optlen); break; } off += optlen; /* Sanity check. */ if (off > skip) { 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), &ip6); /* We don't do IPv6 Jumbograms. */ if (ip6.ip6_plen == 0) { DPRINTF("unsupported IPv6 jumbogram\n"); 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), &ip6); ip6optlen = skip - sizeof(struct ip6_hdr); /* Let's deal with the remaining headers (if any). */ if (ip6optlen > 0) { if (m->m_len <= skip) { ptr = malloc(ip6optlen, M_XDATA, M_NOWAIT); if (ptr == NULL) { DPRINTF("failed to allocate " "memory for IPv6 headers\n"); m_freem(m); return ENOBUFS; } /* * Copy all the protocol headers after * the IPv6 header. */ m_copydata(m, sizeof(struct ip6_hdr), ip6optlen, 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 < ip6optlen;) { int noff; if (off + sizeof(*ip6e) > ip6optlen) { goto error6; } ip6e = (struct ip6_ext *)(ptr + off); noff = off + ((ip6e->ip6e_len + 1) << 3); if (noff > ip6optlen) { goto error6; } switch (nxt) { case IPPROTO_HOPOPTS: case IPPROTO_DSTOPTS: /* Zero out mutable options. */ for (count = off + sizeof(struct ip6_ext); count < noff;) { if (ptr[count] == IP6OPT_PAD1) { count++; continue; } if (count + 1 >= noff) { goto error6; } optlen = ptr[count + 1] + 2; if (count + optlen > noff) { goto error6; } if (ptr[count] & IP6OPT_MUTABLE) { memset(ptr + count, 0, optlen); } count += optlen; } if (count != noff) { goto error6; } /* FALLTHROUGH */ case IPPROTO_ROUTING: /* Advance. */ off = noff; nxt = ip6e->ip6e_nxt; break; default: 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), ip6optlen, 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) { const struct auth_hash *ahx; struct tdb_crypto *tc = NULL; struct newah *ah; int hl, rplen, authsize, ahsize, error, stat = AH_STAT_HDROPS; struct cryptodesc *crda; struct cryptop *crp = NULL; bool pool_used; uint8_t nxt; KASSERT(sav != NULL); KASSERT(sav->key_auth != NULL); KASSERT(sav->tdb_authalgxform != NULL); /* Figure out header size. */ rplen = HDRSIZE(sav); /* XXX don't pullup, just copy header */ M_REGION_GET(ah, struct newah *, m, skip, rplen); if (ah == NULL) { /* m already freed */ return ENOBUFS; } nxt = ah->ah_nxt; /* Check replay window, if applicable. */ if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { char buf[IPSEC_LOGSASTRLEN]; DPRINTF("packet replay failure: %s\n", ipsec_logsastr(sav, buf, sizeof(buf))); stat = AH_STAT_REPLAY; error = EACCES; goto bad; } /* Verify AH header length. */ hl = sizeof(struct ah) + (ah->ah_len * sizeof(uint32_t)); ahx = sav->tdb_authalgxform; authsize = AUTHSIZE(sav); ahsize = ah_hdrsiz(sav); if (hl != ahsize) { char buf[IPSEC_ADDRSTRLEN]; DPRINTF("bad authenticator length %u (expecting %lu)" " for packet in SA %s/%08lx\n", hl, (u_long)ahsize, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); stat = AH_STAT_BADAUTHL; error = EACCES; goto bad; } if (skip + ahsize > m->m_pkthdr.len) { char buf[IPSEC_ADDRSTRLEN]; DPRINTF("bad mbuf length %u (expecting >= %lu)" " for packet in SA %s/%08lx\n", m->m_pkthdr.len, (u_long)(skip + ahsize), ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); stat = AH_STAT_BADAUTHL; error = EACCES; goto bad; } AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl); /* Get crypto descriptors. */ crp = crypto_getreq(1); if (crp == NULL) { DPRINTF("failed to acquire crypto descriptor\n"); stat = AH_STAT_CRYPTO; error = ENOBUFS; goto bad; } crda = crp->crp_desc; KASSERT(crda != NULL); 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_key = _KEYBUF(sav->key_auth); crda->crd_klen = _KEYBITS(sav->key_auth); /* Allocate IPsec-specific opaque crypto info. */ size_t size = sizeof(*tc); size_t extra = skip + rplen + authsize; size += extra; if (__predict_true(size <= ah_pool_item_size)) { tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); pool_used = true; } else { /* size can exceed on IPv6 packets with large options. */ tc = kmem_intr_zalloc(size, KM_NOSLEEP); pool_used = false; } if (tc == NULL) { DPRINTF("failed to allocate tdb_crypto\n"); stat = AH_STAT_CRYPTO; error = ENOBUFS; goto bad; } error = m_makewritable(&m, 0, extra, M_NOWAIT); if (error) { DPRINTF("failed to m_makewritable\n"); goto bad; } /* * Save the authenticator, the skipped portion of the packet, * and the AH header. */ m_copydata(m, 0, extra, (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 */ m = NULL; goto bad; } { int s = pserialize_read_enter(); /* * Take another reference to the SA for opencrypto callback. */ if (__predict_false(sav->state == SADB_SASTATE_DEAD)) { pserialize_read_exit(s); stat = AH_STAT_NOTDB; error = ENOENT; goto bad; } KEY_SA_REF(sav); pserialize_read_exit(s); } /* Crypto operation descriptor. */ crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ crp->crp_flags = CRYPTO_F_IMBUF; crp->crp_buf = m; crp->crp_callback = ah_input_cb; crp->crp_sid = sav->tdb_cryptoid; crp->crp_opaque = 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 = nxt; tc->tc_protoff = protoff; tc->tc_skip = skip; tc->tc_sav = sav; DPRINTF("hash over %d bytes, skip %d: " "crda len %d skip %d inject %d\n", crp->crp_ilen, tc->tc_skip, crda->crd_len, crda->crd_skip, crda->crd_inject); crypto_dispatch(crp); return 0; bad: if (tc != NULL) { if (__predict_true(pool_used)) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); } if (crp != NULL) crypto_freereq(crp); if (m != NULL) m_freem(m); AH_STATINC(stat); return error; } #ifdef INET6 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) do { \ if (saidx->dst.sa.sa_family == AF_INET6) { \ (void)ipsec6_common_input_cb(m, sav, skip, protoff); \ } else { \ (void)ipsec4_common_input_cb(m, sav, skip, protoff); \ } \ } while (0) #else #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) \ ((void)ipsec4_common_input_cb(m, sav, skip, protoff)) #endif /* * AH input callback from the crypto driver. */ static void ah_input_cb(struct cryptop *crp) { char buf[IPSEC_ADDRSTRLEN]; int rplen, ahsize, skip, protoff; unsigned char calc[AH_ALEN_MAX]; struct mbuf *m; struct tdb_crypto *tc; struct secasvar *sav; struct secasindex *saidx; uint8_t nxt; char *ptr; int authsize; bool pool_used; size_t size; IPSEC_DECLARE_LOCK_VARIABLE; KASSERT(crp->crp_opaque != NULL); tc = crp->crp_opaque; skip = tc->tc_skip; nxt = tc->tc_nxt; protoff = tc->tc_protoff; m = crp->crp_buf; IPSEC_ACQUIRE_GLOBAL_LOCKS(); sav = tc->tc_sav; saidx = &sav->sah->saidx; KASSERTMSG(saidx->dst.sa.sa_family == AF_INET || saidx->dst.sa.sa_family == AF_INET6, "unexpected protocol family %u", saidx->dst.sa.sa_family); /* Figure out header size. */ rplen = HDRSIZE(sav); authsize = AUTHSIZE(sav); ahsize = ah_hdrsiz(sav); size = sizeof(*tc) + skip + rplen + authsize; if (__predict_true(size <= ah_pool_item_size)) pool_used = true; else pool_used = false; /* Check for crypto errors. */ if (crp->crp_etype) { if (sav->tdb_cryptoid != 0) sav->tdb_cryptoid = crp->crp_sid; AH_STATINC(AH_STAT_NOXFORM); DPRINTF("crypto error %d\n", crp->crp_etype); goto bad; } else { AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); crypto_freereq(crp); /* No longer needed. */ crp = NULL; } if (ipsec_debug) memset(calc, 0, sizeof(calc)); /* Copy authenticator off the packet. */ m_copydata(m, skip + rplen, authsize, calc); ptr = (char *)(tc + 1); const uint8_t *pppp = ptr + skip + rplen; /* Verify authenticator. */ if (!consttime_memequal(pppp, calc, authsize)) { DPRINTF("authentication hash mismatch " \ "over %d bytes " \ "for packet in SA %s/%08lx:\n" \ "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \ "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n", authsize, ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi), calc[0], calc[1], calc[2], calc[3], calc[4], calc[5], calc[6], calc[7], calc[8], calc[9], calc[10], calc[11], pppp[0], pppp[1], pppp[2], pppp[3], pppp[4], pppp[5], pppp[6], pppp[7], pppp[8], pppp[9], pppp[10], pppp[11]); AH_STATINC(AH_STAT_BADAUTH); goto bad; } /* Fix the Next Protocol field. */ ptr[protoff] = nxt; /* Copyback the saved (uncooked) network headers. */ m_copyback(m, 0, skip, ptr); if (__predict_true(pool_used)) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); tc = NULL; /* * Header is now authenticated. */ m->m_flags |= M_AUTHIPHDR; /* * Update replay sequence number, if appropriate. */ if (sav->replay) { uint32_t seq; m_copydata(m, skip + offsetof(struct newah, ah_seq), sizeof(seq), &seq); if (ipsec_updatereplay(ntohl(seq), sav)) { AH_STATINC(AH_STAT_REPLAY); goto bad; } } /* * Remove the AH header and authenticator from the mbuf. */ if (m_striphdr(m, skip, ahsize) != 0) { DPRINTF("mangled mbuf chain for SA %s/%08lx\n", ipsec_address(&saidx->dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); AH_STATINC(AH_STAT_HDROPS); goto bad; } IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff); KEY_SA_UNREF(&sav); IPSEC_RELEASE_GLOBAL_LOCKS(); return; bad: if (sav) KEY_SA_UNREF(&sav); IPSEC_RELEASE_GLOBAL_LOCKS(); if (m != NULL) m_freem(m); if (tc != NULL) { if (pool_used) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); } if (crp != NULL) crypto_freereq(crp); return; } /* * AH output routine, called by ipsec[46]_process_packet(). */ static int ah_output(struct mbuf *m, const struct ipsecrequest *isr, struct secasvar *sav, int skip, int protoff, int flags) { char buf[IPSEC_ADDRSTRLEN]; const struct auth_hash *ahx; struct cryptodesc *crda; struct tdb_crypto *tc; struct mbuf *mi; struct cryptop *crp; uint16_t iplen; int error, rplen, authsize, ahsize, maxpacketsize, roff; uint8_t prot; struct newah *ah; size_t ipoffs; bool pool_used; KASSERT(sav != NULL); KASSERT(sav->tdb_authalgxform != NULL); ahx = sav->tdb_authalgxform; AH_STATINC(AH_STAT_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; ipoffs = offsetof(struct ip, ip_len); break; #endif #ifdef INET6 case AF_INET6: maxpacketsize = IPV6_MAXPACKET; ipoffs = offsetof(struct ip6_hdr, ip6_plen); break; #endif default: DPRINTF("unknown/unsupported protocol " "family %u, SA %s/%08lx\n", sav->sah->saidx.dst.sa.sa_family, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); AH_STATINC(AH_STAT_NOPF); error = EPFNOSUPPORT; goto bad; } if (ahsize + m->m_pkthdr.len > maxpacketsize) { DPRINTF("packet in SA %s/%08lx got too big " "(len %u, max len %u)\n", ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi), ahsize + m->m_pkthdr.len, maxpacketsize); AH_STATINC(AH_STAT_TOOBIG); error = EMSGSIZE; goto bad; } /* Update the counters. */ AH_STATADD(AH_STAT_OBYTES, m->m_pkthdr.len - skip); m = m_clone(m); if (m == NULL) { DPRINTF("cannot clone mbuf chain, SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); AH_STATINC(AH_STAT_HDROPS); error = ENOBUFS; goto bad; } /* Inject AH header. */ mi = m_makespace(m, skip, ahsize, &roff); if (mi == NULL) { DPRINTF("failed to inject %u byte AH header for SA " "%s/%08lx\n", ahsize, ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); AH_STATINC(AH_STAT_HDROPS); 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, char *) + roff); /* Initialize the AH header. */ m_copydata(m, protoff, sizeof(uint8_t), &ah->ah_nxt); ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(uint32_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. */ if (sav->replay) { if (sav->replay->count == ~0 && (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { DPRINTF("replay counter wrapped for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), (u_long) ntohl(sav->spi)); AH_STATINC(AH_STAT_WRAP); error = EINVAL; goto bad; } #ifdef IPSEC_DEBUG /* Emulate replay attack when ipsec_replay is TRUE. */ if (!ipsec_replay) #endif sav->replay->count++; ah->ah_seq = htonl(sav->replay->count); } /* Get crypto descriptors. */ crp = crypto_getreq(1); if (crp == NULL) { DPRINTF("failed to acquire crypto descriptors\n"); AH_STATINC(AH_STAT_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 = _KEYBUF(sav->key_auth); crda->crd_klen = _KEYBITS(sav->key_auth); /* Allocate IPsec-specific opaque crypto info. */ size_t size = sizeof(*tc) + skip; if (__predict_true(size <= ah_pool_item_size)) { tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); pool_used = true; } else { /* size can exceed on IPv6 packets with large options. */ tc = kmem_intr_zalloc(size, KM_NOSLEEP); pool_used = false; } if (tc == NULL) { DPRINTF("failed to allocate tdb_crypto\n"); AH_STATINC(AH_STAT_CRYPTO); error = ENOBUFS; goto bad_crp; } uint8_t *pext = (char *)(tc + 1); /* Save the skipped portion of the packet. */ m_copydata(m, 0, skip, pext); /* * 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. */ memcpy(&iplen, pext + ipoffs, sizeof(iplen)); iplen = htons(ntohs(iplen) + ahsize); m_copyback(m, ipoffs, sizeof(iplen), &iplen); /* Fix the Next Header field in saved header. */ pext[protoff] = IPPROTO_AH; /* Update the Next Protocol field in the IP header. */ prot = IPPROTO_AH; m_copyback(m, protoff, sizeof(prot), &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. */ goto bad_tc; } { int s = pserialize_read_enter(); /* * Take another reference to the SP and the SA for opencrypto callback. */ if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD || sav->state == SADB_SASTATE_DEAD)) { pserialize_read_exit(s); AH_STATINC(AH_STAT_NOTDB); error = ENOENT; goto bad_tc; } KEY_SP_REF(isr->sp); KEY_SA_REF(sav); pserialize_read_exit(s); } /* Crypto operation descriptor. */ crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ crp->crp_flags = CRYPTO_F_IMBUF; crp->crp_buf = m; crp->crp_callback = ah_output_cb; crp->crp_sid = sav->tdb_cryptoid; crp->crp_opaque = tc; /* These are passed as-is to the callback. */ tc->tc_isr = isr; 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; tc->tc_flags = flags; tc->tc_sav = sav; crypto_dispatch(crp); return 0; bad_tc: if (__predict_true(pool_used)) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); bad_crp: crypto_freereq(crp); bad: if (m) m_freem(m); return error; } /* * AH output callback from the crypto driver. */ static void ah_output_cb(struct cryptop *crp) { int skip; struct tdb_crypto *tc; const struct ipsecrequest *isr; struct secasvar *sav; struct mbuf *m; void *ptr; int flags; size_t size; bool pool_used; IPSEC_DECLARE_LOCK_VARIABLE; KASSERT(crp->crp_opaque != NULL); tc = crp->crp_opaque; skip = tc->tc_skip; ptr = (tc + 1); m = crp->crp_buf; size = sizeof(*tc) + skip; pool_used = size <= ah_pool_item_size; IPSEC_ACQUIRE_GLOBAL_LOCKS(); isr = tc->tc_isr; sav = tc->tc_sav; /* Check for crypto errors. */ if (crp->crp_etype) { if (sav->tdb_cryptoid != 0) sav->tdb_cryptoid = crp->crp_sid; AH_STATINC(AH_STAT_NOXFORM); DPRINTF("crypto error %d\n", crp->crp_etype); goto bad; } AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); /* * Copy original headers (with the new protocol number) back * in place. */ m_copyback(m, 0, skip, ptr); flags = tc->tc_flags; /* No longer needed. */ if (__predict_true(pool_used)) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); crypto_freereq(crp); #ifdef IPSEC_DEBUG /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ if (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. */ (void)ipsec_process_done(m, isr, sav, flags); KEY_SA_UNREF(&sav); KEY_SP_UNREF(&isr->sp); IPSEC_RELEASE_GLOBAL_LOCKS(); return; bad: if (sav) KEY_SA_UNREF(&sav); KEY_SP_UNREF(&isr->sp); IPSEC_RELEASE_GLOBAL_LOCKS(); if (m) m_freem(m); if (__predict_true(pool_used)) pool_cache_put(ah_tdb_crypto_pool_cache, tc); else kmem_intr_free(tc, size); crypto_freereq(crp); } static struct xformsw ah_xformsw = { .xf_type = XF_AH, .xf_flags = XFT_AUTH, .xf_name = "IPsec AH", .xf_init = ah_init, .xf_zeroize = ah_zeroize, .xf_input = ah_input, .xf_output = ah_output, .xf_next = NULL, }; void ah_attach(void) { ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS); #define MAXAUTHSIZE(name) \ if ((auth_hash_ ## name).authsize > ah_max_authsize) \ ah_max_authsize = (auth_hash_ ## name).authsize ah_max_authsize = 0; MAXAUTHSIZE(null); MAXAUTHSIZE(md5); MAXAUTHSIZE(sha1); MAXAUTHSIZE(key_md5); MAXAUTHSIZE(key_sha1); MAXAUTHSIZE(hmac_md5); MAXAUTHSIZE(hmac_sha1); MAXAUTHSIZE(hmac_ripemd_160); MAXAUTHSIZE(hmac_md5_96); MAXAUTHSIZE(hmac_sha1_96); MAXAUTHSIZE(hmac_ripemd_160_96); MAXAUTHSIZE(hmac_sha2_256); MAXAUTHSIZE(hmac_sha2_384); MAXAUTHSIZE(hmac_sha2_512); MAXAUTHSIZE(aes_xcbc_mac_96); MAXAUTHSIZE(gmac_aes_128); MAXAUTHSIZE(gmac_aes_192); MAXAUTHSIZE(gmac_aes_256); IPSECLOG(LOG_DEBUG, "ah_max_authsize=%d\n", ah_max_authsize); #undef MAXAUTHSIZE ah_pool_item_size = sizeof(struct tdb_crypto) + sizeof(struct ip) + MAX_IPOPTLEN + sizeof(struct ah) + sizeof(uint32_t) + ah_max_authsize; ah_tdb_crypto_pool_cache = pool_cache_init(ah_pool_item_size, coherency_unit, 0, 0, "ah_tdb_crypto", NULL, IPL_SOFTNET, NULL, NULL, NULL); xform_register(&ah_xformsw); }