ref: 540373b9f603825f27f853a441c6c046a04a0972
dir: /sys/src/9/ip/esp.c/
/* * Encapsulating Security Payload for IPsec for IPv4, rfc1827. * extended to IPv6. * rfc2104 defines hmac computation. * currently only implements tunnel mode. * TODO: verify aes algorithms; * transport mode (host-to-host) */ #include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "ip.h" #include "ipv6.h" #include "libsec.h" #define BITS2BYTES(bi) (((bi) + BI2BY - 1) / BI2BY) #define BYTES2BITS(by) ((by) * BI2BY) typedef struct Algorithm Algorithm; typedef struct Esp4hdr Esp4hdr; typedef struct Esp6hdr Esp6hdr; typedef struct Espcb Espcb; typedef struct Esphdr Esphdr; typedef struct Esppriv Esppriv; typedef struct Esptail Esptail; typedef struct Userhdr Userhdr; enum { Encrypt, Decrypt, IP_ESPPROTO = 50, /* IP v4 and v6 protocol number */ Esp4hdrlen = IP4HDR + 8, Esp6hdrlen = IP6HDR + 8, Esptaillen = 2, /* does not include pad or auth data */ Userhdrlen = 4, /* user-visible header size - if enabled */ Desblk = BITS2BYTES(64), Des3keysz = BITS2BYTES(192), Aesblk = BITS2BYTES(128), Aeskeysz = BITS2BYTES(128), }; struct Esphdr { uchar espspi[4]; /* Security parameter index */ uchar espseq[4]; /* Sequence number */ uchar payload[]; }; /* * tunnel-mode (network-to-network, etc.) layout is: * new IP hdrs | ESP hdr | * enc { orig IP hdrs | TCP/UDP hdr | user data | ESP trailer } | ESP ICV * * transport-mode (host-to-host) layout would be: * orig IP hdrs | ESP hdr | * enc { TCP/UDP hdr | user data | ESP trailer } | ESP ICV */ struct Esp4hdr { /* ipv4 header */ uchar vihl; /* Version and header length */ uchar tos; /* Type of service */ uchar length[2]; /* packet length */ uchar id[2]; /* Identification */ uchar frag[2]; /* Fragment information */ uchar Unused; uchar espproto; /* Protocol */ uchar espplen[2]; /* Header plus data length */ uchar espsrc[4]; /* Ip source */ uchar espdst[4]; /* Ip destination */ Esphdr; }; /* tunnel-mode layout */ struct Esp6hdr { IPV6HDR; Esphdr; }; struct Esptail { uchar pad; uchar nexthdr; }; /* IP-version-dependent data */ typedef struct Versdep Versdep; struct Versdep { ulong version; ulong iphdrlen; ulong hdrlen; /* iphdrlen + esp hdr len */ ulong spi; uchar laddr[IPaddrlen]; uchar raddr[IPaddrlen]; }; /* header as seen by the user */ struct Userhdr { uchar nexthdr; /* next protocol */ uchar unused[3]; }; struct Esppriv { uvlong in; ulong inerrors; }; /* * protocol specific part of Conv */ struct Espcb { int incoming; int header; /* user-level header */ ulong spi; ulong seq; /* last seq sent */ ulong window; /* for replay attacks */ char *espalg; void *espstate; /* other state for esp */ int espivlen; /* in bytes */ int espblklen; int (*cipher)(Espcb*, uchar *buf, int len); char *ahalg; void *ahstate; /* other state for esp */ int ahlen; /* auth data length in bytes */ int ahblklen; int (*auth)(Espcb*, uchar *buf, int len, uchar *hash); DigestState *ds; }; struct Algorithm { char *name; int keylen; /* in bits */ void (*init)(Espcb*, char* name, uchar *key, unsigned keylen); }; static Conv* convlookup(Proto *esp, ulong spi); static char *setalg(Espcb *ecb, char **f, int n, Algorithm *alg); static void espkick(void *x); static void nullespinit(Espcb*, char*, uchar *key, unsigned keylen); static void des3espinit(Espcb*, char*, uchar *key, unsigned keylen); static void aescbcespinit(Espcb*, char*, uchar *key, unsigned keylen); static void aesctrespinit(Espcb*, char*, uchar *key, unsigned keylen); static void desespinit(Espcb *ecb, char *name, uchar *k, unsigned n); static void nullahinit(Espcb*, char*, uchar *key, unsigned keylen); static void shaahinit(Espcb*, char*, uchar *key, unsigned keylen); static void md5ahinit(Espcb*, char*, uchar *key, unsigned keylen); static Algorithm espalg[] = { "null", 0, nullespinit, "des3_cbc", 192, des3espinit, /* new rfc2451, des-ede3 */ "aes_128_cbc", 128, aescbcespinit, /* new rfc3602 */ "aes_ctr", 128, aesctrespinit, /* new rfc3686 */ "des_56_cbc", 64, desespinit, /* rfc2405, deprecated */ nil, 0, nil, }; static Algorithm ahalg[] = { "null", 0, nullahinit, "hmac_sha1_96", 128, shaahinit, /* rfc2404 */ "hmac_md5_96", 128, md5ahinit, /* rfc2403 */ nil, 0, nil, }; static char* espconnect(Conv *c, char **argv, int argc) { char *p, *pp, *e = nil; ulong spi; Espcb *ecb = (Espcb*)c->ptcl; switch(argc) { default: e = "bad args to connect"; break; case 2: p = strchr(argv[1], '!'); if(p == nil){ e = "malformed address"; break; } *p++ = 0; if (parseip(c->raddr, argv[1]) == -1) { e = Ebadip; break; } findlocalip(c->p->f, c->laddr, c->raddr); ecb->incoming = 0; ecb->seq = 0; if(strcmp(p, "*") == 0) { qlock(c->p); for(;;) { spi = nrand(1<<16) + 256; if(convlookup(c->p, spi) == nil) break; } qunlock(c->p); ecb->spi = spi; ecb->incoming = 1; qhangup(c->wq, nil); } else { spi = strtoul(p, &pp, 10); if(pp == p) { e = "malformed address"; break; } ecb->spi = spi; qhangup(c->rq, nil); } nullespinit(ecb, "null", nil, 0); nullahinit(ecb, "null", nil, 0); } Fsconnected(c, e); return e; } static int espstate(Conv *c, char *state, int n) { return snprint(state, n, "%s", c->inuse?"Open\n":"Closed\n"); } static void espcreate(Conv *c) { c->rq = qopen(64*1024, Qmsg, 0, 0); c->wq = qopen(64*1024, Qkick, espkick, c); } static void espclose(Conv *c) { Espcb *ecb; qclose(c->rq); qclose(c->wq); qclose(c->eq); ipmove(c->laddr, IPnoaddr); ipmove(c->raddr, IPnoaddr); ecb = (Espcb*)c->ptcl; free(ecb->espstate); free(ecb->ahstate); memset(ecb, 0, sizeof(Espcb)); } static int convipvers(Conv *c) { if((memcmp(c->raddr, v4prefix, IPv4off) == 0 && memcmp(c->laddr, v4prefix, IPv4off) == 0) || ipcmp(c->raddr, IPnoaddr) == 0) return V4; else return V6; } static int pktipvers(Fs *f, Block **bpp) { if (*bpp == nil || BLEN(*bpp) == 0) { /* get enough to identify the IP version */ *bpp = pullupblock(*bpp, IP4HDR); if(*bpp == nil) { netlog(f, Logesp, "esp: short packet\n"); return 0; } } return (((Esp4hdr*)(*bpp)->rp)->vihl & 0xf0) == IP_VER4? V4: V6; } static void getverslens(int version, Versdep *vp) { vp->version = version; switch(vp->version) { case V4: vp->iphdrlen = IP4HDR; vp->hdrlen = Esp4hdrlen; break; case V6: vp->iphdrlen = IP6HDR; vp->hdrlen = Esp6hdrlen; break; default: panic("esp: getverslens version %d wrong", version); } } static void getpktspiaddrs(uchar *pkt, Versdep *vp) { Esp4hdr *eh4; Esp6hdr *eh6; switch(vp->version) { case V4: eh4 = (Esp4hdr*)pkt; v4tov6(vp->raddr, eh4->espsrc); v4tov6(vp->laddr, eh4->espdst); vp->spi = nhgetl(eh4->espspi); break; case V6: eh6 = (Esp6hdr*)pkt; ipmove(vp->raddr, eh6->src); ipmove(vp->laddr, eh6->dst); vp->spi = nhgetl(eh6->espspi); break; default: panic("esp: getpktspiaddrs vp->version %ld wrong", vp->version); } } /* * encapsulate next IP packet on x's write queue in IP/ESP packet * and initiate output of the result. */ static void espkick(void *x) { int nexthdr, payload, pad, align; uchar *auth; Block *bp; Conv *c = x; Esp4hdr *eh4; Esp6hdr *eh6; Espcb *ecb; Esptail *et; Userhdr *uh; Versdep vers; getverslens(convipvers(c), &vers); bp = qget(c->wq); if(bp == nil) return; qlock(c); ecb = c->ptcl; if(ecb->header) { /* make sure the message has a User header */ bp = pullupblock(bp, Userhdrlen); if(bp == nil) { qunlock(c); return; } uh = (Userhdr*)bp->rp; nexthdr = uh->nexthdr; bp->rp += Userhdrlen; } else { nexthdr = 0; /* what should this be? */ } payload = BLEN(bp) + ecb->espivlen; /* Make space to fit ip header */ bp = padblock(bp, vers.hdrlen + ecb->espivlen); getpktspiaddrs(bp->rp, &vers); align = 4; if(ecb->espblklen > align) align = ecb->espblklen; if(align % ecb->ahblklen != 0) panic("espkick: ahblklen is important after all"); pad = (align-1) - (payload + Esptaillen-1)%align; /* * Make space for tail * this is done by calling padblock with a negative size * Padblock does not change bp->wp! */ bp = padblock(bp, -(pad+Esptaillen+ecb->ahlen)); bp->wp += pad+Esptaillen+ecb->ahlen; et = (Esptail*)(bp->rp + vers.hdrlen + payload + pad); /* fill in tail */ et->pad = pad; et->nexthdr = nexthdr; /* encrypt the payload */ ecb->cipher(ecb, bp->rp + vers.hdrlen, payload + pad + Esptaillen); auth = bp->rp + vers.hdrlen + payload + pad + Esptaillen; /* fill in head; construct a new IP header and an ESP header */ if (vers.version == V4) { eh4 = (Esp4hdr *)bp->rp; eh4->vihl = IP_VER4; v6tov4(eh4->espsrc, c->laddr); v6tov4(eh4->espdst, c->raddr); eh4->espproto = IP_ESPPROTO; eh4->frag[0] = 0; eh4->frag[1] = 0; hnputl(eh4->espspi, ecb->spi); hnputl(eh4->espseq, ++ecb->seq); } else { eh6 = (Esp6hdr *)bp->rp; eh6->vcf[0] = IP_VER6; ipmove(eh6->src, c->laddr); ipmove(eh6->dst, c->raddr); eh6->proto = IP_ESPPROTO; hnputl(eh6->espspi, ecb->spi); hnputl(eh6->espseq, ++ecb->seq); } /* compute secure hash */ ecb->auth(ecb, bp->rp + vers.iphdrlen, (vers.hdrlen - vers.iphdrlen) + payload + pad + Esptaillen, auth); qunlock(c); /* print("esp: pass down: %uld\n", BLEN(bp)); */ if (vers.version == V4) ipoput4(c->p->f, bp, 0, c->ttl, c->tos, c); else ipoput6(c->p->f, bp, 0, c->ttl, c->tos, c); } /* * decapsulate IP packet from IP/ESP packet in bp and * pass the result up the spi's Conv's read queue. */ void espiput(Proto *esp, Ipifc*, Block *bp) { int payload, nexthdr; uchar *auth, *espspi; Conv *c; Espcb *ecb; Esptail *et; Fs *f; Userhdr *uh; Versdep vers; f = esp->f; getverslens(pktipvers(f, &bp), &vers); bp = pullupblock(bp, vers.hdrlen + Esptaillen); if(bp == nil) { netlog(f, Logesp, "esp: short packet\n"); return; } getpktspiaddrs(bp->rp, &vers); qlock(esp); /* Look for a conversation structure for this port */ c = convlookup(esp, vers.spi); if(c == nil) { qunlock(esp); netlog(f, Logesp, "esp: no conv %I -> %I!%lud\n", vers.raddr, vers.laddr, vers.spi); icmpnoconv(f, bp); freeblist(bp); return; } qlock(c); qunlock(esp); ecb = c->ptcl; /* too hard to do decryption/authentication on block lists */ if(bp->next) bp = concatblock(bp); if(BLEN(bp) < vers.hdrlen + ecb->espivlen + Esptaillen + ecb->ahlen) { qunlock(c); netlog(f, Logesp, "esp: short block %I -> %I!%lud\n", vers.raddr, vers.laddr, vers.spi); freeb(bp); return; } auth = bp->wp - ecb->ahlen; espspi = vers.version == V4? ((Esp4hdr*)bp->rp)->espspi: ((Esp6hdr*)bp->rp)->espspi; /* compute secure hash and authenticate */ if(!ecb->auth(ecb, espspi, auth - espspi, auth)) { qunlock(c); print("esp: bad auth %I -> %I!%ld\n", vers.raddr, vers.laddr, vers.spi); netlog(f, Logesp, "esp: bad auth %I -> %I!%lud\n", vers.raddr, vers.laddr, vers.spi); freeb(bp); return; } payload = BLEN(bp) - vers.hdrlen - ecb->ahlen; if(payload <= 0 || payload % 4 != 0 || payload % ecb->espblklen != 0) { qunlock(c); netlog(f, Logesp, "esp: bad length %I -> %I!%lud payload=%d BLEN=%zd\n", vers.raddr, vers.laddr, vers.spi, payload, BLEN(bp)); freeb(bp); return; } /* decrypt payload */ if(!ecb->cipher(ecb, bp->rp + vers.hdrlen, payload)) { qunlock(c); print("esp: cipher failed %I -> %I!%ld: %s\n", vers.raddr, vers.laddr, vers.spi, up->errstr); netlog(f, Logesp, "esp: cipher failed %I -> %I!%lud: %s\n", vers.raddr, vers.laddr, vers.spi, up->errstr); freeb(bp); return; } payload -= Esptaillen; et = (Esptail*)(bp->rp + vers.hdrlen + payload); payload -= et->pad + ecb->espivlen; nexthdr = et->nexthdr; if(payload <= 0) { qunlock(c); netlog(f, Logesp, "esp: short packet after decrypt %I -> %I!%lud\n", vers.raddr, vers.laddr, vers.spi); freeb(bp); return; } /* trim packet */ bp->rp += vers.hdrlen + ecb->espivlen; /* toss original IP & ESP hdrs */ bp->wp = bp->rp + payload; if(ecb->header) { /* assume Userhdrlen < Esp4hdrlen < Esp6hdrlen */ bp->rp -= Userhdrlen; uh = (Userhdr*)bp->rp; memset(uh, 0, Userhdrlen); uh->nexthdr = nexthdr; } /* ingress filtering here? */ if(qfull(c->rq)){ netlog(f, Logesp, "esp: qfull %I -> %I.%uld\n", vers.raddr, vers.laddr, vers.spi); freeblist(bp); }else { // print("esp: pass up: %uld\n", BLEN(bp)); qpass(c->rq, bp); /* pass packet up the read queue */ } qunlock(c); } char* espctl(Conv *c, char **f, int n) { Espcb *ecb = c->ptcl; char *e = nil; if(strcmp(f[0], "esp") == 0) e = setalg(ecb, f, n, espalg); else if(strcmp(f[0], "ah") == 0) e = setalg(ecb, f, n, ahalg); else if(strcmp(f[0], "header") == 0) ecb->header = 1; else if(strcmp(f[0], "noheader") == 0) ecb->header = 0; else e = "unknown control request"; return e; } /* called from icmp(v6) for unreachable hosts, time exceeded, etc. */ void espadvise(Proto *esp, Block *bp, char *msg) { Conv *c; Versdep vers; getverslens(pktipvers(esp->f, &bp), &vers); getpktspiaddrs(bp->rp, &vers); qlock(esp); c = convlookup(esp, vers.spi); if(c != nil && !c->ignoreadvice) { qhangup(c->rq, msg); qhangup(c->wq, msg); } qunlock(esp); freeblist(bp); } int espstats(Proto *esp, char *buf, int len) { Esppriv *upriv; upriv = esp->priv; return snprint(buf, len, "%llud %lud\n", upriv->in, upriv->inerrors); } static int esplocal(Conv *c, char *buf, int len) { Espcb *ecb = c->ptcl; int n; qlock(c); if(ecb->incoming) n = snprint(buf, len, "%I!%uld\n", c->laddr, ecb->spi); else n = snprint(buf, len, "%I\n", c->laddr); qunlock(c); return n; } static int espremote(Conv *c, char *buf, int len) { Espcb *ecb = c->ptcl; int n; qlock(c); if(ecb->incoming) n = snprint(buf, len, "%I\n", c->raddr); else n = snprint(buf, len, "%I!%uld\n", c->raddr, ecb->spi); qunlock(c); return n; } static Conv* convlookup(Proto *esp, ulong spi) { Conv *c, **p; Espcb *ecb; for(p=esp->conv; *p; p++){ c = *p; ecb = c->ptcl; if(ecb->incoming && ecb->spi == spi) return c; } return nil; } static char * setalg(Espcb *ecb, char **f, int n, Algorithm *alg) { uchar *key; int c, nbyte, nchar; uint i; if(n < 2 || n > 3) return "bad format"; for(; alg->name; alg++) if(strcmp(f[1], alg->name) == 0) break; if(alg->name == nil) return "unknown algorithm"; nbyte = (alg->keylen + 7) >> 3; if (n == 2) nchar = 0; else nchar = strlen(f[2]); if(nchar != 2 * nbyte) /* TODO: maybe < is ok */ return "key not required length"; /* convert hex digits from ascii, in place */ for(i=0; i<nchar; i++) { c = f[2][i]; if(c >= '0' && c <= '9') f[2][i] -= '0'; else if(c >= 'a' && c <= 'f') f[2][i] -= 'a'-10; else if(c >= 'A' && c <= 'F') f[2][i] -= 'A'-10; else return "non-hex character in key"; } /* collapse hex digits into complete bytes in reverse order in key */ key = smalloc(nbyte); for(i = 0; i < nchar && i/2 < nbyte; i++) { c = f[2][nchar-i-1]; if(i&1) c <<= 4; key[i/2] |= c; } alg->init(ecb, alg->name, key, alg->keylen); free(key); return nil; } /* * null encryption */ static int nullcipher(Espcb*, uchar*, int) { return 1; } static void nullespinit(Espcb *ecb, char *name, uchar*, unsigned) { ecb->espalg = name; ecb->espblklen = 1; ecb->espivlen = 0; ecb->cipher = nullcipher; } static int nullauth(Espcb*, uchar*, int, uchar*) { return 1; } static void nullahinit(Espcb *ecb, char *name, uchar*, unsigned) { ecb->ahalg = name; ecb->ahblklen = 1; ecb->ahlen = 0; ecb->auth = nullauth; } /* * sha1 */ static void seanq_hmac_sha1(uchar hash[SHA1dlen], uchar *t, long tlen, uchar *key, long klen) { int i; uchar ipad[Hmacblksz+1], opad[Hmacblksz+1], innerhash[SHA1dlen]; DigestState *digest; memset(ipad, 0x36, Hmacblksz); memset(opad, 0x5c, Hmacblksz); ipad[Hmacblksz] = opad[Hmacblksz] = 0; for(i = 0; i < klen; i++){ ipad[i] ^= key[i]; opad[i] ^= key[i]; } digest = sha1(ipad, Hmacblksz, nil, nil); sha1(t, tlen, innerhash, digest); digest = sha1(opad, Hmacblksz, nil, nil); sha1(innerhash, SHA1dlen, hash, digest); } static int shaauth(Espcb *ecb, uchar *t, int tlen, uchar *auth) { int r; uchar hash[SHA1dlen]; memset(hash, 0, SHA1dlen); seanq_hmac_sha1(hash, t, tlen, (uchar*)ecb->ahstate, BITS2BYTES(128)); r = memcmp(auth, hash, ecb->ahlen) == 0; memmove(auth, hash, ecb->ahlen); return r; } static void shaahinit(Espcb *ecb, char *name, uchar *key, unsigned klen) { if(klen != 128) panic("shaahinit: bad keylen"); klen /= BI2BY; ecb->ahalg = name; ecb->ahblklen = 1; ecb->ahlen = BITS2BYTES(96); ecb->auth = shaauth; ecb->ahstate = smalloc(klen); memmove(ecb->ahstate, key, klen); } /* * aes */ static int aescbccipher(Espcb *ecb, uchar *p, int n) /* 128-bit blocks */ { uchar tmp[AESbsize], q[AESbsize]; uchar *pp, *tp, *ip, *eip, *ep; AESstate *ds = ecb->espstate; ep = p + n; if(ecb->incoming) { memmove(ds->ivec, p, AESbsize); p += AESbsize; while(p < ep){ memmove(tmp, p, AESbsize); aes_decrypt(ds->dkey, ds->rounds, p, q); memmove(p, q, AESbsize); tp = tmp; ip = ds->ivec; for(eip = ip + AESbsize; ip < eip; ){ *p++ ^= *ip; *ip++ = *tp++; } } } else { memmove(p, ds->ivec, AESbsize); for(p += AESbsize; p < ep; p += AESbsize){ pp = p; ip = ds->ivec; for(eip = ip + AESbsize; ip < eip; ) *pp++ ^= *ip++; aes_encrypt(ds->ekey, ds->rounds, p, q); memmove(ds->ivec, q, AESbsize); memmove(p, q, AESbsize); } } return 1; } static void aescbcespinit(Espcb *ecb, char *name, uchar *k, unsigned n) { uchar key[Aeskeysz], ivec[Aeskeysz]; int i; n = BITS2BYTES(n); if(n > Aeskeysz) n = Aeskeysz; memset(key, 0, sizeof(key)); memmove(key, k, n); for(i = 0; i < Aeskeysz; i++) ivec[i] = nrand(256); ecb->espalg = name; ecb->espblklen = Aesblk; ecb->espivlen = Aesblk; ecb->cipher = aescbccipher; ecb->espstate = smalloc(sizeof(AESstate)); setupAESstate(ecb->espstate, key, n /* keybytes */, ivec); } static int aesctrcipher(Espcb *ecb, uchar *p, int n) /* 128-bit blocks */ { uchar tmp[AESbsize], q[AESbsize]; uchar *pp, *tp, *ip, *eip, *ep; AESstate *ds = ecb->espstate; ep = p + n; if(ecb->incoming) { memmove(ds->ivec, p, AESbsize); p += AESbsize; while(p < ep){ memmove(tmp, p, AESbsize); aes_decrypt(ds->dkey, ds->rounds, p, q); memmove(p, q, AESbsize); tp = tmp; ip = ds->ivec; for(eip = ip + AESbsize; ip < eip; ){ *p++ ^= *ip; *ip++ = *tp++; } } } else { memmove(p, ds->ivec, AESbsize); for(p += AESbsize; p < ep; p += AESbsize){ pp = p; ip = ds->ivec; for(eip = ip + AESbsize; ip < eip; ) *pp++ ^= *ip++; aes_encrypt(ds->ekey, ds->rounds, p, q); memmove(ds->ivec, q, AESbsize); memmove(p, q, AESbsize); } } return 1; } static void aesctrespinit(Espcb *ecb, char *name, uchar *k, unsigned n) { uchar key[Aesblk], ivec[Aesblk]; int i; n = BITS2BYTES(n); if(n > Aeskeysz) n = Aeskeysz; memset(key, 0, sizeof(key)); memmove(key, k, n); for(i = 0; i < Aesblk; i++) ivec[i] = nrand(256); ecb->espalg = name; ecb->espblklen = Aesblk; ecb->espivlen = Aesblk; ecb->cipher = aesctrcipher; ecb->espstate = smalloc(sizeof(AESstate)); setupAESstate(ecb->espstate, key, n /* keybytes */, ivec); } /* * md5 */ static void seanq_hmac_md5(uchar hash[MD5dlen], uchar *t, long tlen, uchar *key, long klen) { int i; uchar ipad[Hmacblksz+1], opad[Hmacblksz+1], innerhash[MD5dlen]; DigestState *digest; memset(ipad, 0x36, Hmacblksz); memset(opad, 0x5c, Hmacblksz); ipad[Hmacblksz] = opad[Hmacblksz] = 0; for(i = 0; i < klen; i++){ ipad[i] ^= key[i]; opad[i] ^= key[i]; } digest = md5(ipad, Hmacblksz, nil, nil); md5(t, tlen, innerhash, digest); digest = md5(opad, Hmacblksz, nil, nil); md5(innerhash, MD5dlen, hash, digest); } static int md5auth(Espcb *ecb, uchar *t, int tlen, uchar *auth) { uchar hash[MD5dlen]; int r; memset(hash, 0, MD5dlen); seanq_hmac_md5(hash, t, tlen, (uchar*)ecb->ahstate, BITS2BYTES(128)); r = memcmp(auth, hash, ecb->ahlen) == 0; memmove(auth, hash, ecb->ahlen); return r; } static void md5ahinit(Espcb *ecb, char *name, uchar *key, unsigned klen) { if(klen != 128) panic("md5ahinit: bad keylen"); klen = BITS2BYTES(klen); ecb->ahalg = name; ecb->ahblklen = 1; ecb->ahlen = BITS2BYTES(96); ecb->auth = md5auth; ecb->ahstate = smalloc(klen); memmove(ecb->ahstate, key, klen); } /* * des, single and triple */ static int descipher(Espcb *ecb, uchar *p, int n) { DESstate *ds = ecb->espstate; if(ecb->incoming) { memmove(ds->ivec, p, Desblk); desCBCdecrypt(p + Desblk, n - Desblk, ds); } else { memmove(p, ds->ivec, Desblk); desCBCencrypt(p + Desblk, n - Desblk, ds); } return 1; } static int des3cipher(Espcb *ecb, uchar *p, int n) { DES3state *ds = ecb->espstate; if(ecb->incoming) { memmove(ds->ivec, p, Desblk); des3CBCdecrypt(p + Desblk, n - Desblk, ds); } else { memmove(p, ds->ivec, Desblk); des3CBCencrypt(p + Desblk, n - Desblk, ds); } return 1; } static void desespinit(Espcb *ecb, char *name, uchar *k, unsigned n) { uchar key[Desblk], ivec[Desblk]; int i; n = BITS2BYTES(n); if(n > Desblk) n = Desblk; memset(key, 0, sizeof(key)); memmove(key, k, n); for(i = 0; i < Desblk; i++) ivec[i] = nrand(256); ecb->espalg = name; ecb->espblklen = Desblk; ecb->espivlen = Desblk; ecb->cipher = descipher; ecb->espstate = smalloc(sizeof(DESstate)); setupDESstate(ecb->espstate, key, ivec); } static void des3espinit(Espcb *ecb, char *name, uchar *k, unsigned n) { uchar key[3][Desblk], ivec[Desblk]; int i; n = BITS2BYTES(n); if(n > Des3keysz) n = Des3keysz; memset(key, 0, sizeof(key)); memmove(key, k, n); for(i = 0; i < Desblk; i++) ivec[i] = nrand(256); ecb->espalg = name; ecb->espblklen = Desblk; ecb->espivlen = Desblk; ecb->cipher = des3cipher; ecb->espstate = smalloc(sizeof(DES3state)); setupDES3state(ecb->espstate, key, ivec); } /* * interfacing to devip */ void espinit(Fs *fs) { Proto *esp; esp = smalloc(sizeof(Proto)); esp->priv = smalloc(sizeof(Esppriv)); esp->name = "esp"; esp->connect = espconnect; esp->announce = nil; esp->ctl = espctl; esp->state = espstate; esp->create = espcreate; esp->close = espclose; esp->rcv = espiput; esp->advise = espadvise; esp->stats = espstats; esp->local = esplocal; esp->remote = espremote; esp->ipproto = IP_ESPPROTO; esp->nc = Nchans; esp->ptclsize = sizeof(Espcb); Fsproto(fs, esp); }