/* $KAME: esp_aesctr.c,v 1.2 2003/07/20 00:29:37 itojun Exp $ */ /* * Copyright (C) 1995, 1996, 1997, 1998 and 2003 WIDE Project. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * $FreeBSD$ */ #include <sys/param.h> #include <sys/systm.h> #include <sys/socket.h> #include <sys/queue.h> #include <sys/syslog.h> #include <sys/mbuf.h> #include <net/if.h> #include <net/route.h> #include <netinet/in.h> #include <netinet6/ipsec.h> #include <netinet6/esp.h> #include <netinet6/esp_aesctr.h> #include <netkey/key.h> #include <crypto/rijndael/rijndael.h> #include <net/net_osdep.h> #define AES_BLOCKSIZE 16 #define NONCESIZE 4 union cblock { struct { u_int8_t nonce[4]; u_int8_t iv[16]; u_int32_t ctr; } v __attribute__((__packed__)); u_int8_t cblock[16]; }; typedef struct { u_int32_t r_ek[(RIJNDAEL_MAXNR+1)*4]; int r_nr; /* key-length-dependent number of rounds */ } aesctr_ctx; int esp_aesctr_mature(sav) struct secasvar *sav; { int keylen; const struct esp_algorithm *algo; algo = esp_algorithm_lookup(sav->alg_enc); if (!algo) { ipseclog((LOG_ERR, "esp_aeesctr_mature %s: unsupported algorithm.\n", algo->name)); return 1; } keylen = sav->key_enc->sadb_key_bits; if (keylen < algo->keymin || algo->keymax < keylen) { ipseclog((LOG_ERR, "esp_aesctr_mature %s: invalid key length %d.\n", algo->name, sav->key_enc->sadb_key_bits)); return 1; } /* rijndael key + nonce */ if (!(keylen == 128 + 32 || keylen == 192 + 32 || keylen == 256 + 32)) { ipseclog((LOG_ERR, "esp_aesctr_mature %s: invalid key length %d.\n", algo->name, keylen)); return 1; } return 0; } size_t esp_aesctr_schedlen(algo) const struct esp_algorithm *algo; { return sizeof(aesctr_ctx); } int esp_aesctr_schedule(algo, sav) const struct esp_algorithm *algo; struct secasvar *sav; { aesctr_ctx *ctx; int keylen; /* SA key = AES key + nonce */ keylen = _KEYLEN(sav->key_enc) * 8 - NONCESIZE * 8; ctx = (aesctr_ctx *)sav->sched; if ((ctx->r_nr = rijndaelKeySetupEnc(ctx->r_ek, (char *)_KEYBUF(sav->key_enc), keylen)) == 0) return -1; return 0; } int esp_aesctr_decrypt(m, off, sav, algo, ivlen) struct mbuf *m; size_t off; struct secasvar *sav; const struct esp_algorithm *algo; int ivlen; { struct mbuf *s; struct mbuf *d, *d0 = NULL, *dp; int soff, doff; /* offset from the head of chain, to head of this mbuf */ int sn, dn; /* offset from the head of the mbuf, to meat */ size_t ivoff, bodyoff; union cblock cblock; u_int8_t keystream[AES_BLOCKSIZE], *nonce; u_int32_t ctr; u_int8_t *ivp; u_int8_t sbuf[AES_BLOCKSIZE], *sp, *dst; struct mbuf *scut; int scutoff; int i; int blocklen; aesctr_ctx *ctx; if (ivlen != sav->ivlen) { ipseclog((LOG_ERR, "esp_aesctr_decrypt %s: " "unsupported ivlen %d\n", algo->name, ivlen)); goto fail; } /* assumes blocklen == padbound */ blocklen = algo->padbound; ivoff = off + sizeof(struct newesp); bodyoff = off + sizeof(struct newesp) + ivlen; /* setup counter block */ nonce = _KEYBUF(sav->key_enc) + _KEYLEN(sav->key_enc) - NONCESIZE; bcopy(nonce, cblock.v.nonce, NONCESIZE); m_copydata(m, ivoff, ivlen, cblock.v.iv); ctr = 1; if (m->m_pkthdr.len < bodyoff) { ipseclog((LOG_ERR, "esp_aesctr_decrypt %s: bad len %d/%lu\n", algo->name, m->m_pkthdr.len, (unsigned long)bodyoff)); goto fail; } if ((m->m_pkthdr.len - bodyoff) % blocklen) { ipseclog((LOG_ERR, "esp_aesctr_decrypt %s: " "payload length must be multiple of %d\n", algo->name, blocklen)); goto fail; } s = m; d = d0 = dp = NULL; soff = doff = sn = dn = 0; ivp = sp = NULL; /* skip bodyoff */ while (soff < bodyoff) { if (soff + s->m_len > bodyoff) { sn = bodyoff - soff; break; } soff += s->m_len; s = s->m_next; } scut = s; scutoff = sn; /* skip over empty mbuf */ while (s && s->m_len == 0) s = s->m_next; while (soff < m->m_pkthdr.len) { /* source */ if (sn + blocklen <= s->m_len) { /* body is continuous */ sp = mtod(s, u_int8_t *) + sn; } else { /* body is non-continuous */ m_copydata(s, sn, blocklen, (caddr_t)sbuf); sp = sbuf; } /* destination */ if (!d || dn + blocklen > d->m_len) { if (d) dp = d; MGET(d, M_DONTWAIT, MT_DATA); i = m->m_pkthdr.len - (soff + sn); if (d && i > MLEN) { MCLGET(d, M_DONTWAIT); if ((d->m_flags & M_EXT) == 0) { m_free(d); d = NULL; } } if (!d) { goto nomem; } if (!d0) d0 = d; if (dp) dp->m_next = d; d->m_len = 0; d->m_len = (M_TRAILINGSPACE(d) / blocklen) * blocklen; if (d->m_len > i) d->m_len = i; dn = 0; } /* put counter into counter block */ cblock.v.ctr = htonl(ctr); /* setup keystream */ ctx = (aesctr_ctx *)sav->sched; rijndaelEncrypt(ctx->r_ek, ctx->r_nr, cblock.cblock, keystream); bcopy(sp, mtod(d, u_int8_t *) + dn, blocklen); dst = mtod(d, u_int8_t *) + dn; for (i = 0; i < blocklen; i++) dst[i] ^= keystream[i]; ctr++; sn += blocklen; dn += blocklen; /* find the next source block */ while (s && sn >= s->m_len) { sn -= s->m_len; soff += s->m_len; s = s->m_next; } /* skip over empty mbuf */ while (s && s->m_len == 0) s = s->m_next; } m_freem(scut->m_next); scut->m_len = scutoff; scut->m_next = d0; /* just in case */ bzero(&cblock, sizeof(cblock)); bzero(keystream, sizeof(keystream)); return 0; fail: m_freem(m); if (d0) m_freem(d0); return EINVAL; nomem: m_freem(m); if (d0) m_freem(d0); return ENOBUFS; } int esp_aesctr_encrypt(m, off, plen, sav, algo, ivlen) struct mbuf *m; size_t off; size_t plen; struct secasvar *sav; const struct esp_algorithm *algo; int ivlen; { struct mbuf *s; struct mbuf *d, *d0, *dp; int soff, doff; /* offset from the head of chain, to head of this mbuf */ int sn, dn; /* offset from the head of the mbuf, to meat */ size_t ivoff, bodyoff; union cblock cblock; u_int8_t keystream[AES_BLOCKSIZE], *nonce; u_int32_t ctr; u_int8_t sbuf[AES_BLOCKSIZE], *sp, *dst; struct mbuf *scut; int scutoff; int i; int blocklen; aesctr_ctx *ctx; if (ivlen != sav->ivlen) { ipseclog((LOG_ERR, "esp_aesctr_encrypt %s: " "unsupported ivlen %d\n", algo->name, ivlen)); m_freem(m); return EINVAL; } /* assumes blocklen == padbound */ blocklen = algo->padbound; ivoff = off + sizeof(struct newesp); bodyoff = off + sizeof(struct newesp) + ivlen; /* put iv into the packet. */ /* maybe it is better to overwrite dest, not source */ m_copyback(m, ivoff, ivlen, sav->iv); /* setup counter block */ nonce = _KEYBUF(sav->key_enc) + _KEYLEN(sav->key_enc) - NONCESIZE; bcopy(nonce, cblock.v.nonce, NONCESIZE); m_copydata(m, ivoff, ivlen, cblock.v.iv); ctr = 1; if (m->m_pkthdr.len < bodyoff) { ipseclog((LOG_ERR, "esp_aesctr_encrypt %s: bad len %d/%lu\n", algo->name, m->m_pkthdr.len, (unsigned long)bodyoff)); m_freem(m); return EINVAL; } if ((m->m_pkthdr.len - bodyoff) % blocklen) { ipseclog((LOG_ERR, "esp_aesctr_encrypt %s: " "payload length must be multiple of %lu\n", algo->name, (unsigned long)algo->padbound)); m_freem(m); return EINVAL; } s = m; d = d0 = dp = NULL; soff = doff = sn = dn = 0; sp = NULL; /* skip bodyoff */ while (soff < bodyoff) { if (soff + s->m_len > bodyoff) { sn = bodyoff - soff; break; } soff += s->m_len; s = s->m_next; } scut = s; scutoff = sn; /* skip over empty mbuf */ while (s && s->m_len == 0) s = s->m_next; while (soff < m->m_pkthdr.len) { /* source */ if (sn + blocklen <= s->m_len) { /* body is continuous */ sp = mtod(s, u_int8_t *) + sn; } else { /* body is non-continuous */ m_copydata(s, sn, blocklen, (caddr_t)sbuf); sp = sbuf; } /* destination */ if (!d || dn + blocklen > d->m_len) { if (d) dp = d; MGET(d, M_DONTWAIT, MT_DATA); i = m->m_pkthdr.len - (soff + sn); if (d && i > MLEN) { MCLGET(d, M_DONTWAIT); if ((d->m_flags & M_EXT) == 0) { m_free(d); d = NULL; } } if (!d) { m_freem(m); if (d0) m_freem(d0); return ENOBUFS; } if (!d0) d0 = d; if (dp) dp->m_next = d; d->m_len = 0; d->m_len = (M_TRAILINGSPACE(d) / blocklen) * blocklen; if (d->m_len > i) d->m_len = i; dn = 0; } /* put counter into counter block */ cblock.v.ctr = htonl(ctr); /* setup keystream */ ctx = (aesctr_ctx *)sav->sched; rijndaelEncrypt(ctx->r_ek, ctx->r_nr, cblock.cblock, keystream); bcopy(sp, mtod(d, u_int8_t *) + dn, blocklen); dst = mtod(d, u_int8_t *) + dn; for (i = 0; i < blocklen; i++) dst[i] ^= keystream[i]; ctr++; sn += blocklen; dn += blocklen; /* find the next source block */ while (s && sn >= s->m_len) { sn -= s->m_len; soff += s->m_len; s = s->m_next; } /* skip over empty mbuf */ while (s && s->m_len == 0) s = s->m_next; } m_freem(scut->m_next); scut->m_len = scutoff; scut->m_next = d0; /* just in case */ bzero(&cblock, sizeof(cblock)); bzero(keystream, sizeof(keystream)); key_sa_stir_iv(sav); return 0; }