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/*
* 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 aesahinit(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 */
/* rc4 was never required, was used in original bandt */
// "rc4_128", 128, rc4espinit,
nil, 0, nil,
};
static Algorithm ahalg[] =
{
"null", 0, nullahinit,
"hmac_sha1_96", 128, shaahinit, /* rfc2404 */
"aes_xcbc_mac_96", 128, aesahinit, /* new rfc3566 */
"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=%lud\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) {
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
*/
/* ah_aes_xcbc_mac_96, rfc3566 */
static int
aesahauth(Espcb *ecb, uchar *t, int tlen, uchar *auth)
{
int r;
uchar hash[AESdlen];
memset(hash, 0, AESdlen);
ecb->ds = hmac_aes(t, tlen, (uchar*)ecb->ahstate, BITS2BYTES(96), hash,
ecb->ds);
r = memcmp(auth, hash, ecb->ahlen) == 0;
memmove(auth, hash, ecb->ahlen);
return r;
}
static void
aesahinit(Espcb *ecb, char *name, uchar *key, unsigned klen)
{
if(klen != 128)
panic("aesahinit: keylen not 128");
klen /= BI2BY;
ecb->ahalg = name;
ecb->ahblklen = 1;
ecb->ahlen = BITS2BYTES(96);
ecb->auth = aesahauth;
ecb->ahstate = smalloc(klen);
memmove(ecb->ahstate, key, klen);
}
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);
}