ref: 6fe180657f3a7a17801cb9aa36c8fe9abda34ac7
dir: /sys/src/cmd/aux/wpa.c/
#include <u.h>
#include <libc.h>
#include <ip.h>
#include <mp.h>
#include <libsec.h>
#include <auth.h>
enum {
PTKlen = 512/8,
GTKlen = 256/8,
MIClen = 16,
Noncelen = 32,
Eaddrlen = 6,
};
enum {
Fptk = 1<<3,
Fins = 1<<6,
Fack = 1<<7,
Fmic = 1<<8,
Fsec = 1<<9,
Ferr = 1<<10,
Freq = 1<<11,
Fenc = 1<<12,
Keydescrlen = 1+2+2+8+32+16+8+8+16+2,
};
typedef struct Keydescr Keydescr;
struct Keydescr
{
uchar type[1];
uchar flags[2];
uchar keylen[2];
uchar repc[8];
uchar nonce[32];
uchar eapoliv[16];
uchar rsc[8];
uchar id[8];
uchar mic[16];
uchar datalen[2];
uchar data[];
};
typedef struct Cipher Cipher;
struct Cipher
{
char *name;
int keylen;
};
Cipher tkip = { "tkip", 32 };
Cipher ccmp = { "ccmp", 16 };
Cipher *peercipher;
Cipher *groupcipher;
int background;
int prompt;
int debug;
int fd, cfd;
char *dev;
char devdir[40];
uchar ptk[PTKlen];
char essid[32+1];
uvlong lastrepc;
uchar rsntkipoui[4] = {0x00, 0x0F, 0xAC, 0x02};
uchar rsnccmpoui[4] = {0x00, 0x0F, 0xAC, 0x04};
uchar rsnapskoui[4] = {0x00, 0x0F, 0xAC, 0x02};
uchar rsnie[] = {
0x30, /* RSN */
0x14, /* length */
0x01, 0x00, /* version 1 */
0x00, 0x0F, 0xAC, 0x04, /* group cipher suite CCMP */
0x01, 0x00, /* pairwise cipher suite count 1 */
0x00, 0x0F, 0xAC, 0x04, /* pairwise cipher suite CCMP */
0x01, 0x00, /* authentication suite count 1 */
0x00, 0x0F, 0xAC, 0x02, /* authentication suite PSK */
0x00, 0x00, /* capabilities */
};
uchar wpa1oui[4] = {0x00, 0x50, 0xF2, 0x01};
uchar wpatkipoui[4] = {0x00, 0x50, 0xF2, 0x02};
uchar wpaapskoui[4] = {0x00, 0x50, 0xF2, 0x02};
uchar wpaie[] = {
0xdd, /* vendor specific */
0x16, /* length */
0x00, 0x50, 0xf2, 0x01, /* WPAIE type 1 */
0x01, 0x00, /* version 1 */
0x00, 0x50, 0xf2, 0x02, /* group cipher suite TKIP */
0x01, 0x00, /* pairwise cipher suite count 1 */
0x00, 0x50, 0xf2, 0x02, /* pairwise cipher suite TKIP */
0x01, 0x00, /* authentication suite count 1 */
0x00, 0x50, 0xf2, 0x02, /* authentication suite PSK */
};
int
hextob(char *s, char **sp, uchar *b, int n)
{
int r;
n <<= 1;
for(r = 0; r < n && *s; s++){
*b <<= 4;
if(*s >= '0' && *s <= '9')
*b |= (*s - '0');
else if(*s >= 'a' && *s <= 'f')
*b |= 10+(*s - 'a');
else if(*s >= 'A' && *s <= 'F')
*b |= 10+(*s - 'A');
else break;
if((++r & 1) == 0)
b++;
}
if(sp != nil)
*sp = s;
return r >> 1;
}
char*
getifstats(char *key, char *val, int nval)
{
char buf[8*1024], *f[2], *p, *e;
int fd, n;
snprint(buf, sizeof(buf), "%s/ifstats", devdir);
if((fd = open(buf, OREAD)) < 0)
return nil;
n = readn(fd, buf, sizeof(buf)-1);
close(fd);
if(n <= 0)
return nil;
buf[n] = 0;
for(p = buf; (e = strchr(p, '\n')) != nil; p = e){
*e++ = 0;
if(gettokens(p, f, 2, "\t\r\n ") != 2)
continue;
if(strcmp(f[0], key) != 0)
continue;
strncpy(val, f[1], nval);
val[nval-1] = 0;
return val;
}
return nil;
}
char*
getessid(void)
{
return getifstats("essid:", essid, sizeof(essid));
}
int
connected(void)
{
char status[1024];
if(getifstats("status:", status, sizeof(status)) == nil)
return 0;
if(strcmp(status, "connecting") == 0)
return 0;
if(strcmp(status, "unauthenticated") == 0)
return 0;
if(debug)
fprint(2, "status: %s\n", status);
return 1;
}
int
buildrsne(uchar rsne[258])
{
char buf[1024];
uchar brsne[258];
int brsnelen;
uchar *p, *w, *e;
int i, n;
if(getifstats("brsne:", buf, sizeof(buf)) == nil)
return 0; /* not an error, might be old kernel */
brsnelen = hextob(buf, nil, brsne, sizeof(brsne));
if(brsnelen <= 4){
trunc: sysfatal("invalid or truncated RSNE; brsne: %s", buf);
return 0;
}
w = rsne;
p = brsne;
e = p + brsnelen;
if(p[0] == 0x30){
p += 2;
/* RSN */
*w++ = 0x30;
*w++ = 0; /* length */
} else if(p[0] == 0xDD){
p += 2;
if((e - p) < 4 || memcmp(p, wpa1oui, 4) != 0){
sysfatal("unrecognized WPAIE type; brsne: %s", buf);
return 0;
}
/* WPA */
*w++ = 0xDD;
*w++ = 0; /* length */
memmove(w, wpa1oui, 4);
w += 4;
p += 4;
} else {
sysfatal("unrecognized RSNE type; brsne: %s", buf);
return 0;
}
if((e - p) < 6)
goto trunc;
*w++ = *p++; /* version */
*w++ = *p++;
if(rsne[0] == 0x30){
if(memcmp(p, rsnccmpoui, 4) == 0)
groupcipher = &ccmp;
else if(memcmp(p, rsntkipoui, 4) == 0)
groupcipher = &tkip;
else {
sysfatal("unrecognized RSN group cipher; brsne: %s", buf);
return 0;
}
} else {
if(memcmp(p, wpatkipoui, 4) != 0){
sysfatal("unrecognized WPA group cipher; brsne: %s", buf);
return 0;
}
groupcipher = &tkip;
}
memmove(w, p, 4); /* group cipher */
w += 4;
p += 4;
if((e - p) < 6)
goto trunc;
*w++ = 0x01; /* # of peer ciphers */
*w++ = 0x00;
n = *p++;
n |= *p++ << 8;
if(n <= 0)
goto trunc;
peercipher = &tkip;
for(i=0; i<n; i++){
if((e - p) < 4)
goto trunc;
if(rsne[0] == 0x30 && memcmp(p, rsnccmpoui, 4) == 0 && peercipher == &tkip)
peercipher = &ccmp;
p += 4;
}
if(peercipher == &ccmp)
memmove(w, rsnccmpoui, 4);
else if(rsne[0] == 0x30)
memmove(w, rsntkipoui, 4);
else
memmove(w, wpatkipoui, 4);
w += 4;
if((e - p) < 6)
goto trunc;
*w++ = 0x01; /* # of auth suites */
*w++ = 0x00;
n = *p++;
n |= *p++ << 8;
if(n <= 0)
goto trunc;
for(i=0; i<n; i++){
if((e - p) < 4)
goto trunc;
/* look for PSK oui */
if(rsne[0] == 0x30){
if(memcmp(p, rsnapskoui, 4) == 0)
break;
} else {
if(memcmp(p, wpaapskoui, 4) == 0)
break;
}
p += 4;
}
if(i >= n){
sysfatal("auth suite is not PSK; brsne: %s", buf);
return 0;
}
memmove(w, p, 4);
w += 4;
if(rsne[0] == 0x30){
/* RSN caps */
*w++ = 0x00;
*w++ = 0x00;
}
rsne[1] = (w - rsne) - 2;
return w - rsne;
}
int
getptk( uchar smac[Eaddrlen], uchar amac[Eaddrlen],
uchar snonce[Noncelen], uchar anonce[Noncelen],
uchar ptk[PTKlen])
{
uchar buf[2*Eaddrlen + 2*Noncelen], *p;
AuthRpc *rpc;
int afd, ret;
char *s;
ret = -1;
s = nil;
rpc = nil;
if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)
goto out;
if((rpc = auth_allocrpc(afd)) == nil)
goto out;
if((s = getessid()) == nil)
goto out;
if((s = smprint("proto=wpapsk role=client essid=%q", s)) == nil)
goto out;
if((ret = auth_rpc(rpc, "start", s, strlen(s))) != ARok)
goto out;
p = buf;
memmove(p, smac, Eaddrlen); p += Eaddrlen;
memmove(p, amac, Eaddrlen); p += Eaddrlen;
memmove(p, snonce, Noncelen); p += Noncelen;
memmove(p, anonce, Noncelen); p += Noncelen;
if((ret = auth_rpc(rpc, "write", buf, p - buf)) != ARok)
goto out;
if((ret = auth_rpc(rpc, "read", nil, 0)) != ARok)
goto out;
if(rpc->narg != PTKlen){
ret = -1;
goto out;
}
memmove(ptk, rpc->arg, PTKlen);
ret = 0;
out:
free(s);
if(afd >= 0) close(afd);
if(rpc != nil) auth_freerpc(rpc);
return ret;
}
int
Hfmt(Fmt *f)
{
uchar *p, *e;
p = va_arg(f->args, uchar*);
e = p;
if(f->prec >= 0)
e += f->prec;
for(; p != e; p++)
if(fmtprint(f, "%.2x", *p) < 0)
return -1;
return 0;
}
void
dumpkeydescr(Keydescr *kd)
{
static struct {
int flag;
char *name;
} flags[] = {
Fptk, "ptk",
Fins, "ins",
Fack, "ack",
Fmic, "mic",
Fsec, "sec",
Ferr, "err",
Freq, "req",
Fenc, "enc",
};
int i, f;
f = kd->flags[0]<<8 | kd->flags[1];
fprint(2, "type=%.*H vers=%d flags=%.*H ( ",
sizeof(kd->type), kd->type, kd->flags[1] & 7,
sizeof(kd->flags), kd->flags);
for(i=0; i<nelem(flags); i++)
if(flags[i].flag & f)
fprint(2, "%s ", flags[i].name);
fprint(2, ") len=%.*H\nrepc=%.*H nonce=%.*H\neapoliv=%.*H rsc=%.*H id=%.*H mic=%.*H\n",
sizeof(kd->keylen), kd->keylen,
sizeof(kd->repc), kd->repc,
sizeof(kd->nonce), kd->nonce,
sizeof(kd->eapoliv), kd->eapoliv,
sizeof(kd->rsc), kd->rsc,
sizeof(kd->id), kd->id,
sizeof(kd->mic), kd->mic);
i = kd->datalen[0]<<8 | kd->datalen[1];
fprint(2, "data[%.4x]=%.*H\n", i, i, kd->data);
}
int
rc4unwrap(uchar key[16], uchar iv[16], uchar *data, int len)
{
uchar seed[32];
RC4state rs;
memmove(seed, iv, 16);
memmove(seed+16, key, 16);
setupRC4state(&rs, seed, sizeof(seed));
rc4skip(&rs, 256);
rc4(&rs, data, len);
return len;
}
int
aesunwrap(uchar *key, int nkey, uchar *data, int len)
{
static uchar IV[8] = { 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, 0xa6, };
uchar B[16], *R;
AESstate s;
uint t;
int n;
len -= 8;
if(len < 16 || (len % 8) != 0)
return -1;
n = len/8;
t = n*6;
setupAESstate(&s, key, nkey, 0);
memmove(B, data, 8);
memmove(data, data+8, n*8);
do {
for(R = data + (n - 1)*8; R >= data; t--, R -= 8){
memmove(B+8, R, 8);
B[7] ^= (t >> 0);
B[6] ^= (t >> 8);
B[5] ^= (t >> 16);
B[4] ^= (t >> 24);
aes_decrypt(s.dkey, s.rounds, B, B);
memmove(R, B+8, 8);
}
} while(t > 0);
if(memcmp(B, IV, 8) != 0)
return -1;
return n*8;
}
int
calcmic(Keydescr *kd, uchar *msg, int msglen)
{
int vers;
vers = kd->flags[1] & 7;
memset(kd->mic, 0, MIClen);
if(vers == 1){
uchar digest[MD5dlen];
hmac_md5(msg, msglen, ptk, 16, digest, nil);
memmove(kd->mic, digest, MIClen);
return 0;
}
if(vers == 2){
uchar digest[SHA1dlen];
hmac_sha1(msg, msglen, ptk, 16, digest, nil);
memmove(kd->mic, digest, MIClen);
return 0;
}
return -1;
}
int
checkmic(Keydescr *kd, uchar *msg, int msglen)
{
uchar tmp[MIClen];
memmove(tmp, kd->mic, MIClen);
if(calcmic(kd, msg, msglen) != 0)
return -1;
return memcmp(tmp, kd->mic, MIClen) != 0;
}
void
reply(int eapver, uchar smac[Eaddrlen], uchar amac[Eaddrlen], int flags, Keydescr *kd, uchar *data, int datalen)
{
uchar buf[4096], *m, *p = buf;
memmove(p, amac, Eaddrlen); p += Eaddrlen;
memmove(p, smac, Eaddrlen); p += Eaddrlen;
*p++ = 0x88;
*p++ = 0x8e;
m = p;
*p++ = eapver;
*p++ = 0x03;
datalen += Keydescrlen;
*p++ = datalen >> 8;
*p++ = datalen;
datalen -= Keydescrlen;
memmove(p, kd, Keydescrlen);
kd = (Keydescr*)p;
kd->flags[0] = flags >> 8;
kd->flags[1] = flags;
kd->datalen[0] = datalen >> 8;
kd->datalen[1] = datalen;
p = kd->data;
memmove(p, data, datalen);
p += datalen;
memset(kd->mic, 0, MIClen);
if(flags & Fmic)
calcmic(kd, m, p - m);
if(debug != 0){
fprint(2, "\nreply(v%d) %E -> %E: ", eapver, smac, amac);
dumpkeydescr(kd);
}
datalen = p - buf;
if(write(fd, buf, datalen) != datalen)
sysfatal("write: %r");
}
void
usage(void)
{
fprint(2, "%s: [-dp12] [-s essid] dev\n", argv0);
exits("usage");
}
void
main(int argc, char *argv[])
{
uchar mac[Eaddrlen], buf[1024];
static uchar brsne[258];
char addr[128];
uchar *rsne;
int rsnelen;
int n, try;
quotefmtinstall();
fmtinstall('H', Hfmt);
fmtinstall('E', eipfmt);
rsne = nil;
rsnelen = -1;
peercipher = nil;
groupcipher = nil;
ARGBEGIN {
case 'd':
debug = 1;
break;
case 'p':
prompt = 1;
break;
case 's':
strncpy(essid, EARGF(usage()), 32);
break;
case '1':
rsne = wpaie;
rsnelen = sizeof(wpaie);
peercipher = &tkip;
groupcipher = &tkip;
break;
case '2':
rsne = rsnie;
rsnelen = sizeof(rsnie);
peercipher = &ccmp;
groupcipher = &ccmp;
break;
default:
usage();
} ARGEND;
if(*argv != nil)
dev = *argv++;
if(*argv != nil || dev == nil)
usage();
if(myetheraddr(mac, dev) < 0)
sysfatal("can't get mac address: %r");
snprint(addr, sizeof(addr), "%s!0x888e", dev);
if((fd = dial(addr, nil, devdir, &cfd)) < 0)
sysfatal("dial: %r");
if(essid[0] != 0){
if(fprint(cfd, "essid %q", essid) < 0)
sysfatal("write essid: %r");
} else {
getessid();
if(essid[0] == 0)
sysfatal("no essid set");
}
if(prompt){
char *s;
s = smprint("proto=wpapsk essid=%q !password?", essid);
auth_getkey(s);
free(s);
}
Connect:
/* bss scan might not be complete yet, so check for 10 seconds. */
for(try = 10; (background || try >= 0) && !connected(); try--)
sleep(1000);
if(rsnelen <= 0 || rsne == brsne){
rsne = brsne;
rsnelen = buildrsne(rsne);
}
if(rsnelen <= 0){
/* default is WPA */
rsne = wpaie;
rsnelen = sizeof(wpaie);
peercipher = &tkip;
groupcipher = &tkip;
}
if(debug)
fprint(2, "rsne: %.*H\n", rsnelen, rsne);
/*
* we use write() instead of fprint so the message gets written
* at once and not chunked up on fprint buffer.
*/
n = sprint((char*)buf, "auth %.*H", rsnelen, rsne);
if(write(cfd, buf, n) != n)
sysfatal("write auth: %r");
if(!background){
background = 1;
if(!debug){
switch(rfork(RFNOTEG|RFREND|RFPROC|RFNOWAIT)){
default:
exits(nil);
case -1:
sysfatal("fork: %r");
return;
case 0:
break;
}
}
}
lastrepc = 0ULL;
for(;;){
uchar smac[Eaddrlen], amac[Eaddrlen], snonce[Noncelen], anonce[Noncelen], *p, *e, *m;
int proto, eapver, flags, vers, datalen;
uvlong repc, rsc, tsc;
Keydescr *kd;
if((n = read(fd, buf, sizeof(buf))) < 0)
sysfatal("read: %r");
if(n == 0){
if(debug != 0)
fprint(2, "got deassociation\n");
goto Connect;
}
p = buf;
e = buf+n;
if(n < 2*Eaddrlen + 2)
continue;
memmove(smac, p, Eaddrlen); p += Eaddrlen;
memmove(amac, p, Eaddrlen); p += Eaddrlen;
proto = p[0]<<8 | p[1]; p += 2;
if(proto != 0x888e || memcmp(smac, mac, Eaddrlen) != 0)
continue;
m = p;
n = e - p;
if(n < 4)
continue;
eapver = p[0];
if((eapver != 0x01 && eapver != 0x02) || p[1] != 0x03)
continue;
if(debug != 0)
fprint(2, "\nrecv(v%d) %E <- %E: ", eapver, smac, amac);
n = p[2]<<8 | p[3];
p += 4;
if(n < Keydescrlen || p + n > e){
if(debug != 0)
fprint(2, "bad kd size\n");
continue;
}
e = p + n;
kd = (Keydescr*)p;
if(debug != 0)
dumpkeydescr(kd);
if(kd->type[0] != 0xFE && kd->type[0] != 0x02)
continue;
vers = kd->flags[1] & 7;
flags = kd->flags[0]<<8 | kd->flags[1];
datalen = kd->datalen[0]<<8 | kd->datalen[1];
if(kd->data + datalen > e)
continue;
if((flags & Fmic) == 0){
if((flags & (Fptk|Fack)) != (Fptk|Fack))
continue;
memmove(anonce, kd->nonce, sizeof(anonce));
genrandom(snonce, sizeof(snonce));
if(getptk(smac, amac, snonce, anonce, ptk) != 0){
if(debug != 0)
fprint(2, "getptk: %r\n");
continue;
}
/* ack key exchange with mic */
memset(kd->rsc, 0, sizeof(kd->rsc));
memset(kd->eapoliv, 0, sizeof(kd->eapoliv));
memmove(kd->nonce, snonce, sizeof(kd->nonce));
reply(eapver, smac, amac, (flags & ~(Fack|Fins)) | Fmic, kd, rsne, rsnelen);
} else {
uchar gtk[GTKlen];
int gtklen, gtkkid;
if(checkmic(kd, m, e - m) != 0){
if(debug != 0)
fprint(2, "bad mic\n");
continue;
}
repc = (uvlong)kd->repc[7] |
(uvlong)kd->repc[6]<<8 |
(uvlong)kd->repc[5]<<16 |
(uvlong)kd->repc[4]<<24 |
(uvlong)kd->repc[3]<<32 |
(uvlong)kd->repc[2]<<40 |
(uvlong)kd->repc[1]<<48 |
(uvlong)kd->repc[0]<<56;
if(repc <= lastrepc){
if(debug != 0)
fprint(2, "bad repc: %llux <= %llux\n", repc, lastrepc);
continue;
}
lastrepc = repc;
rsc = (uvlong)kd->rsc[0] |
(uvlong)kd->rsc[1]<<8 |
(uvlong)kd->rsc[2]<<16 |
(uvlong)kd->rsc[3]<<24 |
(uvlong)kd->rsc[4]<<32 |
(uvlong)kd->rsc[5]<<40;
if(datalen > 0 && (flags & Fenc) != 0){
if(vers == 1)
datalen = rc4unwrap(ptk+16, kd->eapoliv, kd->data, datalen);
else
datalen = aesunwrap(ptk+16, 16, kd->data, datalen);
if(datalen <= 0){
if(debug != 0)
fprint(2, "bad keywrap\n");
continue;
}
if(debug != 0)
fprint(2, "unwraped keydata[%.4x]=%.*H\n", datalen, datalen, kd->data);
}
gtklen = 0;
gtkkid = -1;
if(kd->type[0] != 0xFE || (flags & (Fptk|Fack)) == (Fptk|Fack)){
uchar *p, *x, *e;
p = kd->data;
e = p + datalen;
for(; p+2 <= e; p = x){
if((x = p+2+p[1]) > e)
break;
if(debug != 0)
fprint(2, "ie=%.2x data[%.2x]=%.*H\n", p[0], p[1], p[1], p+2);
if(p[0] == 0x30){ /* RSN */
}
if(p[0] == 0xDD){ /* WPA */
static uchar oui[] = { 0x00, 0x0f, 0xac, 0x01, };
if(p+2+sizeof(oui) > x || memcmp(p+2, oui, sizeof(oui)) != 0)
continue;
if((flags & Fenc) == 0)
continue; /* ignore gorup key if unencrypted */
gtklen = x - (p + 8);
if(gtklen <= 0)
continue;
if(gtklen > sizeof(gtk))
gtklen = sizeof(gtk);
memmove(gtk, p + 8, gtklen);
gtkkid = p[6] & 3;
}
}
}
if((flags & (Fptk|Fack)) == (Fptk|Fack)){
if(vers != 1) /* in WPA2, RSC is for group key only */
tsc = 0LL;
else {
tsc = rsc;
rsc = 0LL;
}
/* install pairwise receive key */
if(fprint(cfd, "rxkey %.*H %s:%.*H@%llux", Eaddrlen, amac,
peercipher->name, peercipher->keylen, ptk+32, tsc) < 0)
sysfatal("write rxkey: %r");
tsc = 0LL;
memset(kd->rsc, 0, sizeof(kd->rsc));
memset(kd->eapoliv, 0, sizeof(kd->eapoliv));
memset(kd->nonce, 0, sizeof(kd->nonce));
reply(eapver, smac, amac, flags & ~(Fack|Fenc|Fins), kd, nil, 0);
sleep(100);
/* install pairwise transmit key */
if(fprint(cfd, "txkey %.*H %s:%.*H@%llux", Eaddrlen, amac,
peercipher->name, peercipher->keylen, ptk+32, tsc) < 0)
sysfatal("write txkey: %r");
} else
if((flags & (Fptk|Fsec|Fack)) == (Fsec|Fack)){
if(kd->type[0] == 0xFE){
/* WPA always RC4 encrypts the GTK, even tho the flag isnt set */
if((flags & Fenc) == 0)
datalen = rc4unwrap(ptk+16, kd->eapoliv, kd->data, datalen);
gtklen = datalen;
if(gtklen > sizeof(gtk))
gtklen = sizeof(gtk);
memmove(gtk, kd->data, gtklen);
gtkkid = (flags >> 4) & 3;
}
memset(kd->rsc, 0, sizeof(kd->rsc));
memset(kd->eapoliv, 0, sizeof(kd->eapoliv));
memset(kd->nonce, 0, sizeof(kd->nonce));
reply(eapver, smac, amac, flags & ~(Fenc|Fack), kd, nil, 0);
} else
continue;
if(gtklen >= groupcipher->keylen && gtkkid != -1){
/* install group key */
if(fprint(cfd, "rxkey%d %.*H %s:%.*H@%llux",
gtkkid, Eaddrlen, amac,
groupcipher->name, groupcipher->keylen, gtk, rsc) < 0)
sysfatal("write rxkey%d: %r", gtkkid);
}
}
}
}