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authsrv: implement mschapv2 authentication, include MPPE secret in the ticket

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this adds new rpc for mschapv2 authentication (21)

deliver the MPPE secret not after the ticket/authenticator
response as cheartext, but include it in the first 128 bit
of the ticket key. and the authenticator in the first 160 bit
of the authenticator random field.
This commit is contained in:
cinap_lenrek 2018-01-21 22:32:34 +01:00
parent 9840c50a3e
commit fd1e50d653
2 changed files with 71 additions and 17 deletions
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1
sys/include/authsrv.h
View file

@ -61,6 +61,7 @@ enum
AuthHttp=13, /* http domain login */
AuthVNC=14, /* VNC server login (deprecated) */
AuthPAK=19, /* authenticated diffie hellman key agreement */
AuthMSchapv2=21,/* MS chap v2 authentication for ppp */
AuthTs=64, /* ticket encrypted with server's key */
AuthTc, /* ticket encrypted with client's key */
AuthAs, /* server generated authenticator */

87
sys/src/cmd/auth/authsrv.c
View file

@ -27,6 +27,7 @@ enum {
MShashlen = 16,
MSchallen = 8,
MSresplen = 24,
MSchallenv2 = 16,
};
void pak(Ticketreq*);
@ -35,7 +36,7 @@ void challengebox(Ticketreq*);
void changepasswd(Ticketreq*);
void apop(Ticketreq*, int);
void chap(Ticketreq*);
void mschap(Ticketreq*);
void mschap(Ticketreq*, int);
void vnc(Ticketreq*);
int speaksfor(char*, char*);
void replyerror(char*, ...);
@ -49,6 +50,7 @@ void ntv2hash(uchar hash[MShashlen], char *passwd, char *user, char *dom);
void mschalresp(uchar resp[MSresplen], uchar hash[MShashlen], uchar chal[MSchallen]);
void desencrypt(uchar data[8], uchar key[7]);
void tickauthreply(Ticketreq*, Authkey*);
void tickauthreply2(Ticketreq*, Authkey*, uchar *, int, uchar *, int);
void safecpy(char*, char*, int);
void
@ -98,7 +100,10 @@ main(int argc, char *argv[])
chap(&tr);
break;
case AuthMSchap:
mschap(&tr);
mschap(&tr, MSchallen);
break;
case AuthMSchapv2:
mschap(&tr, MSchallenv2);
break;
case AuthCram:
apop(&tr, AuthCram);
@ -674,24 +679,23 @@ getname(int id, uchar *ntblob, int ntbloblen, char *buf, int nbuf)
static uchar ntblobsig[] = {0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
void
mschap(Ticketreq *tr)
mschap(Ticketreq *tr, int nchal)
{
char *secret;
char sbuf[SECRETLEN], windom[128];
uchar chal[CHALLEN], ntblob[1024];
uchar chal[16], ntblob[1024];
uchar hash[MShashlen];
uchar hash2[MShashlen];
uchar resp[MSresplen];
OMSchapreply reply;
int dupe, lmok, ntok, ntbloblen;
uchar phash[SHA1dlen], chash[SHA1dlen], ahash[SHA1dlen];
DigestState *s;
uchar digest[SHA1dlen];
/*
* Create a challenge and send it.
*/
genrandom(chal, sizeof(chal));
if(write(1, chal, sizeof(chal)) != sizeof(chal))
if(write(1, chal, nchal) != nchal)
exits(0);
/*
@ -704,7 +708,7 @@ mschap(Ticketreq *tr)
* CIFS/NTLMv2 uses variable length NT response.
*/
ntbloblen = 0;
if(memcmp(reply.NTresp+16, ntblobsig, sizeof(ntblobsig)) == 0){
if(nchal == MSchallen && memcmp(reply.NTresp+16, ntblobsig, sizeof(ntblobsig)) == 0){
/* Version[1], HiVision[1], Z[6] */
ntbloblen += 1+1+6;
memmove(ntblob, reply.NTresp+16, ntbloblen);
@ -784,13 +788,24 @@ mschap(Ticketreq *tr)
windom[0] = '\0'; /* try NIL domain */
}
dupe = 0;
} else if(nchal == MSchallenv2){
s = sha1((uchar*)reply.LMresp, MSchallenv2, nil, nil);
s = sha1(chal, MSchallenv2, nil, s);
sha1((uchar*)tr->uid, strlen(tr->uid), chash, s);
nthash(hash, secret);
mschalresp(resp, hash, chash);
ntok = lmok = tsmemcmp(resp, reply.NTresp, MSresplen) == 0;
dupe = 0;
} else {
lmhash(hash, secret);
mschalresp(resp, hash, chal);
lmok = tsmemcmp(resp, reply.LMresp, MSresplen) == 0;
nthash(hash, secret);
mschalresp(resp, hash, chal);
ntok = tsmemcmp(resp, reply.NTresp, MSresplen) == 0;
dupe = tsmemcmp(reply.LMresp, reply.NTresp, MSresplen) == 0;
}
@ -815,21 +830,37 @@ mschap(Ticketreq *tr)
succeed(tr->uid);
nthash(hash, secret);
md4(hash, 16, hash, nil);
/*
* reply with ticket & authenticator
*/
tickauthreply(tr, &hkey);
if(nchal == MSchallenv2){
s = sha1(hash, 16, nil, nil);
sha1((uchar*)reply.NTresp, MSresplen, nil, s);
sha1((uchar*)"This is the MPPE Master Key", 27, phash, s);
s = sha1(hash, 16, nil, nil);
sha1((uchar*)reply.NTresp, MSresplen, nil, s);
sha1((uchar*)"Magic server to client signing constant", 39, ahash, s);
s = sha1(ahash, 20, nil, nil);
sha1(chash, 8, nil, s);
sha1((uchar*)"Pad to make it do more than one iteration", 41, ahash, s);
tickauthreply2(tr, &hkey, phash, 16, ahash, 20);
} else {
s = sha1(hash, 16, nil, nil);
sha1(hash, 16, nil, s);
sha1(chal, 8, phash, s);
tickauthreply2(tr, &hkey, phash, 16, nil, 0);
}
syslog(0, AUTHLOG, "mschap-ok %s/%s(%s)", tr->uid, tr->hostid, raddr);
nthash(hash, secret);
md4(hash, 16, hash2, 0);
s = sha1(hash2, 16, 0, 0);
sha1(hash2, 16, 0, s);
sha1(chal, 8, digest, s);
if(write(1, digest, 16) != 16)
exits(0);
exits(0);
}
void
@ -1056,11 +1087,24 @@ mkticket(Ticketreq *tr, Ticket *t)
t->form = ticketform;
}
/*
* reply with ticket and authenticator
*/
/*
* reply with ticket and authenticator
*/
void
tickauthreply(Ticketreq *tr, Authkey *key)
{
tickauthreply2(tr, key, nil, 0, nil, 0);
}
/*
* reply with ticket and authenticator with
* secret s[ns] and authenticator data a[na].
*/
void
tickauthreply2(Ticketreq *tr, Authkey *key, uchar *ps, int ns, uchar *pa, int na)
{
Ticket t;
Authenticator a;
@ -1068,6 +1112,10 @@ tickauthreply(Ticketreq *tr, Authkey *key)
int n;
mkticket(tr, &t);
if(t.form != 0 && ns > 0){
assert(ns <= NONCELEN);
memmove(t.key, ps, ns);
}
t.num = AuthTs;
n = 0;
buf[n++] = AuthOK;
@ -1075,12 +1123,17 @@ tickauthreply(Ticketreq *tr, Authkey *key)
memset(&a, 0, sizeof(a));
memmove(a.chal, t.chal, CHALLEN);
genrandom(a.rand, NONCELEN);
if(t.form != 0 && na > 0){
assert(na <= NONCELEN);
memmove(a.rand, pa, na);
}
a.num = AuthAc;
n += convA2M(&a, buf+n, sizeof(buf)-n, &t);
if(write(1, buf, n) != n)
exits(0);
}
void
safecpy(char *to, char *from, int len)
{