/* $OpenBSD: ip_esp_new.c,v 1.27 1998/11/25 09:56:51 niklas 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). * * 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. * * Copyright (C) 1995, 1996, 1997, 1998 by John Ioannidis, Angelos D. Keromytis * and Niels Provos. * * Permission to use, copy, and modify this software 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. */ /* * Based on draft-ietf-ipsec-esp-v2-00.txt and * draft-ietf-ipsec-ciph-{des,3des}-{derived,expiv}-00.txt */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef ENCDEBUG #define DPRINTF(x) if (encdebug) printf x #else #define DPRINTF(x) #endif extern void encap_sendnotify(int, struct tdb *, void *); extern void des_ecb3_encrypt(caddr_t, caddr_t, caddr_t, caddr_t, caddr_t, int); extern void des_ecb_encrypt(caddr_t, caddr_t, caddr_t, int); extern void des_set_key(caddr_t, caddr_t); static void des1_encrypt(void *, u_int8_t *); static void des3_encrypt(void *, u_int8_t *); static void blf_encrypt(void *, u_int8_t *); static void cast5_encrypt(void *, u_int8_t *); static void des1_decrypt(void *, u_int8_t *); static void des3_decrypt(void *, u_int8_t *); static void blf_decrypt(void *, u_int8_t *); static void cast5_decrypt(void *, u_int8_t *); struct esp_hash esp_new_hash[] = { { ALG_AUTH_MD5, "HMAC-MD5-96", AH_MD5_ALEN, sizeof(MD5_CTX), (void (*) (void *)) MD5Init, (void (*) (void *, u_int8_t *, u_int16_t)) MD5Update, (void (*) (u_int8_t *, void *)) MD5Final }, { ALG_AUTH_SHA1, "HMAC-SHA1-96", AH_SHA1_ALEN, sizeof(SHA1_CTX), (void (*) (void *)) SHA1Init, (void (*) (void *, u_int8_t *, u_int16_t)) SHA1Update, (void (*) (u_int8_t *, void *)) SHA1Final }, { ALG_AUTH_RMD160, "HMAC-RIPEMD-160-96", AH_RMD160_ALEN, sizeof(RMD160_CTX), (void (*)(void *)) RMD160Init, (void (*)(void *, u_int8_t *, u_int16_t)) RMD160Update, (void (*)(u_int8_t *, void *)) RMD160Final } }; struct esp_xform esp_new_xform[] = { { ALG_ENC_DES, "Data Encryption Standard (DES)", ESP_DES_BLKS, ESP_DES_IVS, 8, 8, 8 | 1, des1_encrypt, des1_decrypt }, { ALG_ENC_3DES, "Tripple DES (3DES)", ESP_3DES_BLKS, ESP_3DES_IVS, 24, 24, 8 | 1, des3_encrypt, des3_decrypt }, { ALG_ENC_BLF, "Blowfish", ESP_BLF_BLKS, ESP_BLF_IVS, 5, BLF_MAXKEYLEN, 8 | 1, blf_encrypt, blf_decrypt }, { ALG_ENC_CAST, "CAST", ESP_CAST_BLKS, ESP_CAST_IVS, 5, 16, 8 | 1, cast5_encrypt, cast5_decrypt } }; static void des1_encrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; des_ecb_encrypt(blk, blk, (caddr_t) (xd->edx_eks[0]), 1); } static void des1_decrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; des_ecb_encrypt(blk, blk, (caddr_t) (xd->edx_eks[0]), 0); } static void des3_encrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; des_ecb3_encrypt(blk, blk, (caddr_t) (xd->edx_eks[0]), (caddr_t) (xd->edx_eks[1]), (caddr_t) (xd->edx_eks[2]), 1); } static void des3_decrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; des_ecb3_encrypt(blk, blk, (caddr_t) (xd->edx_eks[2]), (caddr_t) (xd->edx_eks[1]), (caddr_t) (xd->edx_eks[0]), 0); } static void blf_encrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; Blowfish_encipher(&xd->edx_bks, (u_int32_t *)blk, (u_int32_t *) (blk + 4)); } static void blf_decrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; Blowfish_decipher(&xd->edx_bks, (u_int32_t *)blk, (u_int32_t *) (blk + 4)); } static void cast5_encrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; cast_encrypt(&xd->edx_cks, blk, blk); } static void cast5_decrypt(void *pxd, u_int8_t *blk) { struct esp_new_xdata *xd = pxd; cast_decrypt(&xd->edx_cks, blk, blk); } /* * esp_new_attach() is called from the transformation initialization code. * It just returns. */ int esp_new_attach() { DPRINTF(("esp_new_attach(): setting up\n")); return 0; } /* * esp_new_init() is called when an SPI is being set up. It interprets the * encap_msghdr present in m, and sets up the transformation data, in * this case, the encryption and decryption key schedules */ int esp_new_init(struct tdb *tdbp, struct xformsw *xsp, struct mbuf *m) { struct esp_new_xdata *xd; struct esp_new_xencap txd; struct encap_msghdr *em; struct esp_xform *txform; struct esp_hash *thash; caddr_t buffer = NULL; u_int32_t rk[14]; int blocklen, i; if (m->m_len < ENCAP_MSG_FIXED_LEN) { if ((m = m_pullup(m, ENCAP_MSG_FIXED_LEN)) == NULL) { DPRINTF(("esp_new_init(): m_pullup failed\n")); return ENOBUFS; } } em = mtod(m, struct encap_msghdr *); if (em->em_msglen - EMT_SETSPI_FLEN <= ESP_NEW_XENCAP_LEN) { if (encdebug) log(LOG_WARNING, "esp_new_init(): initialization failed\n"); return EINVAL; } /* Just copy the standard fields */ m_copydata(m, EMT_SETSPI_FLEN, ESP_NEW_XENCAP_LEN, (caddr_t) &txd); /* Check whether the encryption algorithm is supported */ for (i = sizeof(esp_new_xform) / sizeof(struct esp_xform) - 1; i >= 0; i--) if (txd.edx_enc_algorithm == esp_new_xform[i].type) break; if (i < 0) { if (encdebug) log(LOG_WARNING, "esp_new_init(): unsupported encryption algorithm %d specified\n", txd.edx_enc_algorithm); return EINVAL; } txform = &esp_new_xform[i]; DPRINTF(("esp_new_init(): initialized TDB with enc algorithm %d: %s\n", txd.edx_enc_algorithm, esp_new_xform[i].name)); /* Check whether the authentication algorithm is supported */ if (txd.edx_flags & ESP_NEW_FLAG_AUTH) { for (i = sizeof(esp_new_hash) / sizeof(struct esp_hash) - 1; i >= 0; i--) if (txd.edx_hash_algorithm == esp_new_hash[i].type) break; if (i < 0) { if (encdebug) log(LOG_WARNING, "esp_new_init(): unsupported authentication algorithm %d specified\n", txd.edx_hash_algorithm); return EINVAL; } DPRINTF(("esp_new_init(): initialized TDB with hash algorithm %d: %s\n", txd.edx_hash_algorithm, esp_new_hash[i].name)); blocklen = HMAC_BLOCK_LEN; thash = &esp_new_hash[i]; } if (txd.edx_ivlen + txd.edx_confkeylen + txd.edx_authkeylen + EMT_SETSPI_FLEN + ESP_NEW_XENCAP_LEN != em->em_msglen) { if (encdebug) log(LOG_WARNING, "esp_new_init(): message length (%d) doesn't match\n", em->em_msglen); return EINVAL; } /* Check the IV length */ if (((txd.edx_ivlen == 0) && !(txform->ivmask&1)) || ((txd.edx_ivlen != 0) && ( !(txd.edx_ivlen & txform->ivmask) || (txd.edx_ivlen & (txd.edx_ivlen - 1))))) { if (encdebug) log(LOG_WARNING, "esp_new_init(): unsupported IV length %d\n", txd.edx_ivlen); return EINVAL; } /* Check the key length */ if (txd.edx_confkeylen < txform->minkey || txd.edx_confkeylen > txform->maxkey) { if (encdebug) log(LOG_WARNING, "esp_new_init(): bad key length %d\n", txd.edx_confkeylen); return EINVAL; } MALLOC(tdbp->tdb_xdata, caddr_t, sizeof(struct esp_new_xdata), M_XDATA, M_WAITOK); if (tdbp->tdb_xdata == NULL) { DPRINTF(("esp_new_init(): MALLOC() failed\n")); return ENOBUFS; } bzero(tdbp->tdb_xdata, sizeof(struct esp_new_xdata)); xd = (struct esp_new_xdata *) tdbp->tdb_xdata; /* Pointer to the transform */ tdbp->tdb_xform = xsp; xd->edx_ivlen = txd.edx_ivlen; xd->edx_enc_algorithm = txd.edx_enc_algorithm; xd->edx_wnd = txd.edx_wnd; xd->edx_flags = txd.edx_flags; xd->edx_hash_algorithm = txd.edx_hash_algorithm; xd->edx_bitmap = 0; xd->edx_xform = txform; /* Pass name of enc algorithm for kernfs */ tdbp->tdb_confname = xd->edx_xform->name; /* Replay counters are mandatory, even without auth */ xd->edx_rpl = AH_HMAC_INITIAL_RPL; /* Copy the IV */ m_copydata(m, EMT_SETSPI_FLEN + ESP_NEW_XENCAP_LEN, xd->edx_ivlen, (caddr_t) xd->edx_iv); /* Copy the key material */ m_copydata(m, EMT_SETSPI_FLEN + ESP_NEW_XENCAP_LEN + xd->edx_ivlen, txd.edx_confkeylen, (caddr_t) rk); switch (xd->edx_enc_algorithm) { case ALG_ENC_DES: des_set_key((caddr_t) rk, (caddr_t) (xd->edx_eks[0])); break; case ALG_ENC_3DES: des_set_key((caddr_t) rk, (caddr_t) (xd->edx_eks[0])); des_set_key((caddr_t) (rk + 2), (caddr_t) (xd->edx_eks[1])); des_set_key((caddr_t) (rk + 4), (caddr_t) (xd->edx_eks[2])); break; case ALG_ENC_BLF: blf_key(&xd->edx_bks, (caddr_t) rk, txd.edx_confkeylen); break; case ALG_ENC_CAST: cast_setkey(&xd->edx_cks, (caddr_t) rk, txd.edx_confkeylen); break; } if (txd.edx_flags & ESP_NEW_FLAG_AUTH) { xd->edx_hash = thash; /* Pass name of auth algorithm for kernfs */ tdbp->tdb_authname = xd->edx_hash->name; DPRINTF(("esp_new_init(): using %d bytes of authentication key\n", txd.edx_authkeylen)); MALLOC(buffer, caddr_t, txd.edx_authkeylen < blocklen ? blocklen : txd.edx_authkeylen, M_TEMP, M_WAITOK); if (buffer == NULL) { DPRINTF(("esp_new_init(): MALLOC() failed\n")); free(tdbp->tdb_xdata, M_XDATA); return ENOBUFS; } bzero(buffer, txd.edx_authkeylen < blocklen ? blocklen : txd.edx_authkeylen); /* Copy the key to the buffer */ m_copydata(m, EMT_SETSPI_FLEN + ESP_NEW_XENCAP_LEN + xd->edx_ivlen + txd.edx_confkeylen, txd.edx_authkeylen, buffer); /* Shorten the key if necessary */ if (txd.edx_authkeylen > blocklen) { xd->edx_hash->Init(&(xd->edx_ictx)); xd->edx_hash->Update(&(xd->edx_ictx), buffer, txd.edx_authkeylen); bzero(buffer, txd.edx_authkeylen < blocklen ? blocklen : txd.edx_authkeylen); xd->edx_hash->Final(buffer, &(xd->edx_ictx)); } /* Precompute the I and O pads of the HMAC */ for (i = 0; i < blocklen; i++) buffer[i] ^= HMAC_IPAD_VAL; xd->edx_hash->Init(&(xd->edx_ictx)); xd->edx_hash->Update(&(xd->edx_ictx), buffer, blocklen); for (i = 0; i < blocklen; i++) buffer[i] ^= (HMAC_IPAD_VAL ^ HMAC_OPAD_VAL); xd->edx_hash->Init(&(xd->edx_octx)); xd->edx_hash->Update(&(xd->edx_octx), buffer, blocklen); bzero(buffer, blocklen); free(buffer, M_TEMP); } bzero(rk, 14 * sizeof(u_int32_t)); /* paranoid */ bzero(ipseczeroes, IPSEC_ZEROES_SIZE); /* paranoid */ return 0; } int esp_new_zeroize(struct tdb *tdbp) { DPRINTF(("esp_new_zeroize(): freeing memory\n")); if (tdbp->tdb_xdata) { FREE(tdbp->tdb_xdata, M_XDATA); tdbp->tdb_xdata = NULL; } return 0; } struct mbuf * esp_new_input(struct mbuf *m, struct tdb *tdb) { u_char iv[ESP_MAX_IVS], niv[ESP_MAX_IVS]; u_char blk[ESP_MAX_BLKS], *lblk, opts[40]; int ohlen, oplen, plen, alen, ilen, i, blks, rest; struct esp_new_xdata *xd; int count, off, errc; struct mbuf *mi, *mo; u_char *idat, *odat, *ivp, *ivn; struct esp_new *esp; struct ip *ip, ipo; u_int32_t btsx; union { MD5_CTX md5ctx; SHA1_CTX sha1ctx; RMD160_CTX rmd160ctx; } ctx; u_char buf[AH_ALEN_MAX], buf2[AH_ALEN_MAX]; xd = (struct esp_new_xdata *) tdb->tdb_xdata; blks = xd->edx_xform->blocksize; if (xd->edx_flags & ESP_NEW_FLAG_AUTH) alen = AH_HMAC_HASHLEN; else alen = 0; if (m->m_len < sizeof(struct ip)) { if ((m = m_pullup(m, sizeof(struct ip))) == NULL) { DPRINTF(("esp_new_input(): (possibly too short) packet dropped\n")); espstat.esps_hdrops++; return NULL; } } ip = mtod(m, struct ip *); ohlen = (ip->ip_hl << 2) + ESP_NEW_FLENGTH; /* Make sure the IP header, any IP options, and the ESP header are here */ if (m->m_len < ohlen + blks) { if ((m = m_pullup(m, ohlen + blks)) == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed\n")); espstat.esps_hdrops++; return NULL; } ip = mtod(m, struct ip *); } esp = (struct esp_new *) ((u_int8_t *) ip + (ip->ip_hl << 2)); ipo = *ip; /* Replay window checking */ if (xd->edx_wnd >= 0) { btsx = ntohl(esp->esp_rpl); if ((errc = checkreplaywindow32(btsx, 0, &(xd->edx_rpl), xd->edx_wnd, &(xd->edx_bitmap))) != 0) { switch(errc) { case 1: if (encdebug) log(LOG_ERR, "esp_new_input(): replay counter wrapped for packets from %x to %x, spi %08x\n", ip->ip_src, ip->ip_dst, ntohl(esp->esp_spi)); espstat.esps_wrap++; break; case 2: case 3: if (encdebug) log(LOG_WARNING, "esp_new_input(): duplicate packet received, %x->%x spi %08x\n", ip->ip_src, ip->ip_dst, ntohl(esp->esp_spi)); espstat.esps_replay++; break; } m_freem(m); return NULL; } } /* Skip the IP header, IP options, SPI, SN and IV and minus Auth Data */ plen = m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - xd->edx_ivlen - alen; if ((plen & (blks - 1)) || (plen <= 0)) { DPRINTF(("esp_new_input(): payload not a multiple of %d octets for packet from %x to %x, spi %08x\n", blks, ipo.ip_src, ipo.ip_dst, ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return NULL; } if (xd->edx_flags & ESP_NEW_FLAG_AUTH) { bcopy(&(xd->edx_ictx), &ctx, xd->edx_hash->ctxsize); /* Auth covers SPI + SN + IV */ oplen = plen + 2 * sizeof(u_int32_t) + xd->edx_ivlen; off = (ip->ip_hl << 2); /* Copy the authentication data */ m_copydata(m, m->m_pkthdr.len - alen, alen, buf); mo = m; while (oplen > 0) { if (mo == 0) panic("esp_new_input(): m_copydata (copy)"); count = min(mo->m_len - off, oplen); xd->edx_hash->Update(&ctx, mtod(mo, unsigned char *) + off, count); oplen -= count; off = 0; mo = mo->m_next; } xd->edx_hash->Final(buf2, &ctx); bcopy(&(xd->edx_octx), &ctx, xd->edx_hash->ctxsize); xd->edx_hash->Update(&ctx, buf2, xd->edx_hash->hashsize); xd->edx_hash->Final(buf2, &ctx); if (bcmp(buf2, buf, AH_HMAC_HASHLEN)) { if (encdebug) log(LOG_ALERT, "esp_new_input(): authentication failed for packet from %x to %x, spi %08x\n", ip->ip_src, ip->ip_dst, ntohl(esp->esp_spi)); espstat.esps_badauth++; m_freem(m); return NULL; } } oplen = plen; ilen = m->m_len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t); idat = mtod(m, unsigned char *) + (ip->ip_hl << 2) + 2 * sizeof(u_int32_t); if (xd->edx_ivlen == 0) /* Derived IV in use */ { bcopy((u_char *) &esp->esp_rpl, iv, sizeof(esp->esp_rpl)); iv[4] = ~iv[0]; iv[5] = ~iv[1]; iv[6] = ~iv[2]; iv[7] = ~iv[3]; } else { bcopy(idat, iv, xd->edx_ivlen); ilen -= xd->edx_ivlen; idat += xd->edx_ivlen; } mi = m; /* * At this point: * plen is # of encapsulated payload octets * ilen is # of octets left in this mbuf * idat is first encapsulated payload octed in this mbuf * same for olen and odat * ivp points to the IV, ivn buffers the next IV. * mi points to the first mbuf * * From now on until the end of the mbuf chain: * . move the next eight octets of the chain into ivn * . decrypt idat and xor with ivp * . swap ivp and ivn. * . repeat */ ivp = iv; ivn = niv; rest = ilen % blks; while (plen > 0) /* while not done */ { if (ilen < blks) { if (rest) { bcopy(idat, blk, rest); odat = idat; } do { mi = (mo = mi)->m_next; if (mi == NULL) panic("esp_new_input(): bad chain (i)\n"); } while (mi->m_len == 0); if (mi->m_len < blks - rest) { if ((mi = m_pullup(mi, blks - rest)) == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed, SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); espstat.esps_hdrops++; return NULL; } /* * m_pullup was not called at the beginning of the chain * but might return a new mbuf, link it into the chain. */ mo->m_next = mi; } ilen = mi->m_len; idat = mtod(mi, u_char *); if (rest) { bcopy(idat, blk + rest, blks - rest); bcopy(blk, ivn, blks); xd->edx_xform->decrypt(xd, blk); for (i = 0; i < blks; i++) blk[i] ^= ivp[i]; ivp = ivn; ivn = (ivp == iv) ? niv : iv; bcopy(blk, odat, rest); bcopy(blk + rest, idat, blks - rest); lblk = blk; /* last block touched */ idat += blks - rest; ilen -= blks - rest; plen -= blks; } rest = ilen % blks; } while (ilen >= blks && plen > 0) { bcopy(idat, ivn, blks); xd->edx_xform->decrypt(xd, idat); for (i = 0; i < blks; i++) idat[i] ^= ivp[i]; ivp = ivn; ivn = (ivp == iv) ? niv : iv; lblk = idat; /* last block touched */ idat += blks; ilen -= blks; plen -= blks; } } /* Save the options */ m_copydata(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip), (caddr_t) opts); if (lblk != blk) bcopy(lblk, blk, blks); /* * Now, the entire chain has been decrypted. As a side effect, * blk[7] contains the next protocol, and blk[6] contains the * amount of padding the original chain had. Chop off the * appropriate parts of the chain, and return. * Verify correct decryption by checking the last padding bytes. */ if ((xd->edx_flags & ESP_NEW_FLAG_NPADDING) == 0) { if (blk[6] + 2 + alen > m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - xd->edx_ivlen) { DPRINTF(("esp_new_input(): invalid padding length %d for packet from %x to %x, SA %x/%08x\n", blk[6], ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return NULL; } if ((blk[6] != blk[5]) && (blk[6] != 0)) { if (encdebug) log(LOG_ALERT, "esp_new_input(): decryption failed for packet from %x to %x, SA %x/%08x\n", ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi)); m_freem(m); return NULL; } m_adj(m, - blk[6] - 2 - alen); /* Old type padding */ } else { if (blk[6] + 1 + alen > m->m_pkthdr.len - (ip->ip_hl << 2) - 2 * sizeof(u_int32_t) - xd->edx_ivlen) { DPRINTF(("esp_new_input(): invalid padding length %d for packet from %x to %x, SA %x/%08x\n", blk[6], ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi))); espstat.esps_badilen++; m_freem(m); return NULL; } if (blk[6] == 0) { if (encdebug) log(LOG_ALERT, "esp_new_input(): decryption failed for packet from %x to %x, SA %x/%08x -- peer is probably using old style padding\n", ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi)); m_freem(m); return NULL; } else if (blk[6] != blk[5] + 1) { if (encdebug) log(LOG_ALERT, "esp_new_input(): decryption failed for packet from %x to %x, SA %x/%08x\n", ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi)); m_freem(m); return NULL; } m_adj(m, - blk[6] - 1 - alen); } m_adj(m, 2 * sizeof(u_int32_t) + xd->edx_ivlen); if (m->m_len < (ipo.ip_hl << 2)) { m = m_pullup(m, (ipo.ip_hl << 2)); if (m == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed for packet from %x to %x, SA %x/%08x\n", ipo.ip_src, ipo.ip_dst, tdb->tdb_dst, ntohl(tdb->tdb_spi))); return NULL; } } ip = mtod(m, struct ip *); ipo.ip_p = blk[7]; ipo.ip_id = htons(ipo.ip_id); ipo.ip_off = 0; ipo.ip_len += (ipo.ip_hl << 2) - 2 * sizeof(u_int32_t) - xd->edx_ivlen - blk[6] - 1 - alen; if ((xd->edx_flags & ESP_NEW_FLAG_NPADDING) == 0) ipo.ip_len -= 1; ipo.ip_len = htons(ipo.ip_len); ipo.ip_sum = 0; *ip = ipo; /* Copy the options back */ m_copyback(m, sizeof(struct ip), (ipo.ip_hl << 2) - sizeof(struct ip), (caddr_t) opts); ip->ip_sum = in_cksum(m, (ip->ip_hl << 2)); /* Update the counters */ tdb->tdb_cur_packets++; tdb->tdb_cur_bytes += ntohs(ip->ip_len) - (ip->ip_hl << 2) + blk[6] + 1 + alen; espstat.esps_ibytes += ntohs(ip->ip_len) - (ip->ip_hl << 2) + blk[6] + 1 + alen; if ((xd->edx_flags & ESP_NEW_FLAG_NPADDING) == 0) { tdb->tdb_cur_bytes++; espstat.esps_ibytes++; } /* Notify on expiration */ if (tdb->tdb_flags & TDBF_SOFT_PACKETS) { if (tdb->tdb_cur_packets >= tdb->tdb_soft_packets) { encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL); tdb->tdb_flags &= ~TDBF_SOFT_PACKETS; } else if (tdb->tdb_flags & TDBF_SOFT_BYTES) if (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes) { encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL); tdb->tdb_flags &= ~TDBF_SOFT_BYTES; } } if (tdb->tdb_flags & TDBF_PACKETS) { if (tdb->tdb_cur_packets >= tdb->tdb_exp_packets) { encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL); tdb_delete(tdb, 0); } else if (tdb->tdb_flags & TDBF_BYTES) if (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes) { encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL); tdb_delete(tdb, 0); } } return m; } int esp_new_output(struct mbuf *m, struct sockaddr_encap *gw, struct tdb *tdb, struct mbuf **mp) { struct esp_new_xdata *xd; struct ip *ip, ipo; int i, ilen, ohlen, nh, rlen, plen, padding, rest; struct esp_new espo; struct mbuf *mi, *mo; u_char *pad, *idat, *odat, *ivp; u_char iv[ESP_MAX_IVS], blk[ESP_MAX_BLKS], auth[AH_ALEN_MAX], opts[40]; union { MD5_CTX md5ctx; SHA1_CTX sha1ctx; RMD160_CTX rmd160ctx; } ctx; int iphlen, blks, alen; xd = (struct esp_new_xdata *) tdb->tdb_xdata; blks = xd->edx_xform->blocksize; if (xd->edx_flags & ESP_NEW_FLAG_AUTH) { alen = AH_HMAC_HASHLEN; DPRINTF(("esp_new_output(): using hash algorithm: %s\n", xd->edx_hash->name)); } else alen = 0; espstat.esps_output++; m = m_pullup(m, sizeof (struct ip)); /* Get IP header in one mbuf */ if (m == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } if (xd->edx_rpl == 0) { if (encdebug) log(LOG_ALERT, "esp_new_output(): SA %x/%0x8 should have expired\n", tdb->tdb_dst, ntohl(tdb->tdb_spi)); m_freem(m); espstat.esps_wrap++; return ENOBUFS; } espo.esp_spi = tdb->tdb_spi; espo.esp_rpl = htonl(xd->edx_rpl++); ip = mtod(m, struct ip *); iphlen = (ip->ip_hl << 2); /* * If options are present, pullup the IP header, the options. */ if (iphlen != sizeof(struct ip)) { m = m_pullup(m, iphlen + 8); if (m == NULL) { DPRINTF(("esp_new_input(): m_pullup() failed for SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } ip = mtod(m, struct ip *); /* Keep the options */ m_copydata(m, sizeof(struct ip), iphlen - sizeof(struct ip), (caddr_t) opts); } ilen = ntohs(ip->ip_len); /* Size of the packet */ ohlen = 2 * sizeof(u_int32_t) + xd->edx_ivlen; ipo = *ip; nh = ipo.ip_p; /* Raw payload length */ rlen = ilen - iphlen; padding = ((blks - ((rlen + 2) % blks)) % blks) + 2; if (iphlen + ohlen + rlen + padding + alen > IP_MAXPACKET) { if (encdebug) log(LOG_ALERT, "esp_new_output(): packet in SA %x/%0x8 got too big\n", tdb->tdb_dst, ntohl(tdb->tdb_spi)); m_freem(m); espstat.esps_toobig++; return EMSGSIZE; } pad = (u_char *) m_pad(m, padding + alen); if (pad == NULL) { DPRINTF(("esp_new_output(): m_pad() failed for SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } /* Self describing padding */ for (i = 0; i < padding - 2; i++) pad[i] = i + 1; if (xd->edx_flags & ESP_NEW_FLAG_NPADDING) pad[padding - 2] = padding - 1; else pad[padding - 2] = padding - 2; pad[padding - 1] = nh; mi = m; plen = rlen + padding; ilen = m->m_len - iphlen; idat = mtod(m, u_char *) + iphlen; if (xd->edx_ivlen == 0) { bcopy((u_char *) &espo.esp_rpl, iv, 4); iv[4] = ~iv[0]; iv[5] = ~iv[1]; iv[6] = ~iv[2]; iv[7] = ~iv[3]; } else { bcopy(xd->edx_iv, iv, xd->edx_ivlen); bcopy(xd->edx_iv, espo.esp_iv, xd->edx_ivlen); } /* Authenticate the esp header */ if (xd->edx_flags & ESP_NEW_FLAG_AUTH) { bcopy(&(xd->edx_ictx), &ctx, xd->edx_hash->ctxsize); xd->edx_hash->Update(&ctx, (unsigned char *) &espo, 2 * sizeof(u_int32_t) + xd->edx_ivlen); } /* Encrypt the payload */ ivp = iv; rest = ilen % blks; while (plen > 0) /* while not done */ { if (ilen < blks) { if (rest) { if (ivp == blk) { bcopy(blk, iv, blks); ivp = iv; } bcopy(idat, blk, rest); odat = idat; } do { mi = (mo = mi)->m_next; if (mi == NULL) panic("esp_new_output(): bad chain (i)\n"); } while (mi->m_len == 0); if (mi->m_len < blks - rest) { if ((mi = m_pullup(mi, blks - rest)) == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } /* * m_pullup was not called at the beginning of the chain * but might return a new mbuf, link it into the chain. */ mo->m_next = mi; } ilen = mi->m_len; idat = mtod(mi, u_char *); if (rest) { bcopy(idat, blk + rest, blks - rest); for (i = 0; i < blks; i++) blk[i] ^= ivp[i]; xd->edx_xform->encrypt(xd, blk); if (xd->edx_flags & ESP_NEW_FLAG_AUTH) xd->edx_hash->Update(&ctx, blk, blks); ivp = blk; bcopy(blk, odat, rest); bcopy(blk + rest, idat, blks - rest); idat += blks - rest; ilen -= blks - rest; plen -= blks; } rest = ilen % blks; } while (ilen >= blks && plen > 0) { for (i = 0; i < blks; i++) idat[i] ^= ivp[i]; xd->edx_xform->encrypt(xd, idat); if (xd->edx_flags & ESP_NEW_FLAG_AUTH) xd->edx_hash->Update(&ctx, idat, blks); ivp = idat; idat += blks; ilen -= blks; plen -= blks; } } /* Put in authentication data */ if (xd->edx_flags & ESP_NEW_FLAG_AUTH) { xd->edx_hash->Final(auth, &ctx); bcopy(&(xd->edx_octx), &ctx, xd->edx_hash->ctxsize); xd->edx_hash->Update(&ctx, auth, xd->edx_hash->hashsize); xd->edx_hash->Final(auth, &ctx); /* Copy the final authenticator */ bcopy(auth, pad + padding, alen); } /* * Done with encryption. Let's wedge in the ESP header * and send it out. */ M_PREPEND(m, ohlen, M_DONTWAIT); if (m == NULL) { DPRINTF(("esp_new_output(): M_PREPEND failed, SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } m = m_pullup(m, iphlen + ohlen); if (m == NULL) { DPRINTF(("esp_new_output(): m_pullup() failed, SA %x/%08x\n", tdb->tdb_dst, ntohl(tdb->tdb_spi))); return ENOBUFS; } /* Fix the length and the next protocol, copy back and off we go */ ipo.ip_len = htons(iphlen + ohlen + rlen + padding + alen); ipo.ip_p = IPPROTO_ESP; /* Save the last encrypted block, to be used as the next IV */ bcopy(ivp, xd->edx_iv, xd->edx_ivlen); m_copyback(m, 0, sizeof(struct ip), (caddr_t) &ipo); /* Copy options, if existing */ if (iphlen != sizeof(struct ip)) m_copyback(m, sizeof(struct ip), iphlen - sizeof(struct ip), (caddr_t) opts); /* Copy in the esp header */ m_copyback(m, iphlen, ohlen, (caddr_t) &espo); *mp = m; /* Update the counters */ tdb->tdb_cur_packets++; tdb->tdb_cur_bytes += rlen + padding; espstat.esps_obytes += rlen + padding; /* Notify on expiration */ if (tdb->tdb_flags & TDBF_SOFT_PACKETS) { if (tdb->tdb_cur_packets >= tdb->tdb_soft_packets) { encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL); tdb->tdb_flags &= ~TDBF_SOFT_PACKETS; } else if (tdb->tdb_flags & TDBF_SOFT_BYTES) if (tdb->tdb_cur_bytes >= tdb->tdb_soft_bytes) { encap_sendnotify(NOTIFY_SOFT_EXPIRE, tdb, NULL); tdb->tdb_flags &= ~TDBF_SOFT_BYTES; } } if (tdb->tdb_flags & TDBF_PACKETS) { if (tdb->tdb_cur_packets >= tdb->tdb_exp_packets) { encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL); tdb_delete(tdb, 0); } else if (tdb->tdb_flags & TDBF_BYTES) if (tdb->tdb_cur_bytes >= tdb->tdb_exp_bytes) { encap_sendnotify(NOTIFY_HARD_EXPIRE, tdb, NULL); tdb_delete(tdb, 0); } } return 0; } /* * return 0 on success * return 1 for counter == 0 * return 2 for very old packet * return 3 for packet within current window but already received */ int checkreplaywindow32(u_int32_t seq, u_int32_t initial, u_int32_t *lastseq, u_int32_t window, u_int32_t *bitmap) { u_int32_t diff; seq -= initial; if (seq == 0) return 1; if (seq > *lastseq - initial) { diff = seq - (*lastseq - initial); if (diff < window) *bitmap = ((*bitmap) << diff) | 1; else *bitmap = 1; *lastseq = seq + initial; return 0; } diff = *lastseq - initial - seq; if (diff >= window) { espstat.esps_wrap++; return 2; } if ((*bitmap) & (((u_int32_t) 1) << diff)) { espstat.esps_replay++; return 3; } *bitmap |= (((u_int32_t) 1) << diff); return 0; }