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/*
* Beware the LM hash is easy to crack (google for l0phtCrack)
* and though NTLM is more secure it is still breakable.
* Ntlmv2 is better and seen as good enough by the windows community.
* For real security use kerberos.
*/
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <auth.h>
#include <libsec.h>
#include <ctype.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
#include "cifs.h"
#define DEF_AUTH "ntlmv2"
static enum {
MACkeylen = 40, /* MAC key len */
MAClen = 8, /* signature length */
MACoff = 14, /* sign. offset from start of SMB (not netbios) pkt */
};
#ifdef DEBUG_MAC
static void
dmp(char *s, int seq, void *buf, int n)
{
int i;
char *p = buf;
print("%s %3d ", s, seq);
while(n > 0){
for(i = 0; i < 16 && n > 0; i++, n--)
print("%02x ", *p++ & 0xff);
if(n > 0)
print("\n");
}
print("\n");
}
#endif
static Auth *
auth_plain(char *windom, char *keyp, uchar *chal, int len)
{
UserPasswd *up;
static Auth *ap;
USED(chal, len);
up = auth_getuserpasswd(auth_getkey, "windom=%s proto=pass service=cifs %s",
windom, keyp);
if(! up)
sysfatal("cannot get key - %r");
ap = emalloc9p(sizeof(Auth));
memset(ap, 0, sizeof(ap));
ap->user = estrdup9p(up->user);
ap->windom = estrdup9p(windom);
ap->resp[0] = estrdup9p(up->passwd);
ap->len[0] = strlen(up->passwd);
memset(up->passwd, 0, strlen(up->passwd));
free(up);
return ap;
}
static Auth *
auth_proto(char *proto, char *windom, char *keyp, uchar *chal, int len)
{
MSchapreply *mcr;
uchar resp[4096];
int nresp;
char user[64];
Auth *ap;
mcr = (MSchapreply*)resp;
nresp = sizeof(resp);
if(strcmp(proto, "mschap") == 0)
nresp = sizeof(*mcr); /* backwards compatibility with old factotum */
nresp = auth_respond(chal, len, user, sizeof user, resp, nresp,
auth_getkey, "proto=%s role=client service=cifs windom=%s %s",
proto, windom, keyp);
if(nresp < 0)
sysfatal("cannot get response - %r");
if(nresp < sizeof(*mcr))
sysfatal("bad response size");
ap = emalloc9p(sizeof(Auth));
memset(ap, 0, sizeof(ap));
ap->user = estrdup9p(user);
ap->windom = estrdup9p(windom);
/* LM response */
ap->len[0] = sizeof(mcr->LMresp);
ap->resp[0] = emalloc9p(ap->len[0]);
memcpy(ap->resp[0], mcr->LMresp, ap->len[0]);
/* NT response */
ap->len[1] = nresp+sizeof(mcr->NTresp)-sizeof(*mcr);
ap->resp[1] = emalloc9p(ap->len[1]);
memcpy(ap->resp[1], mcr->NTresp, ap->len[1]);
return ap;
}
static Auth *
auth_lm_and_ntlm(char *windom, char *keyp, uchar *chal, int len)
{
return auth_proto("mschap", windom, keyp, chal, len);
}
/*
* NTLM response only, the LM response is a just
* copy of the NTLM one. we do this because the lm
* response is easily reversed - Google for l0pht
* for more info.
*/
static Auth *
auth_ntlm(char *windom, char *keyp, uchar *chal, int len)
{
Auth *ap;
if((ap = auth_lm_and_ntlm(windom, keyp, chal, len)) == nil)
return nil;
free(ap->resp[0]);
ap->len[0] = ap->len[1];
ap->resp[0] = emalloc9p(ap->len[0]);
memcpy(ap->resp[0], ap->resp[1], ap->len[0]);
return ap;
}
static Auth *
auth_ntlmv2(char *windom, char *keyp, uchar *chal, int len)
{
return auth_proto("mschap2", windom, keyp, chal, len);
}
struct {
char *name;
Auth *(*func)(char *, char *, uchar *, int);
} methods[] = {
{ "plain", auth_plain },
{ "lm+ntlm", auth_lm_and_ntlm },
{ "ntlm", auth_ntlm },
{ "ntlmv2", auth_ntlmv2 },
// { "kerberos", auth_kerberos },
};
void
autherr(void)
{
int i;
fprint(2, "supported auth methods:\t");
for(i = 0; i < nelem(methods); i++)
fprint(2, "%s ", methods[i].name);
fprint(2, "\n");
exits("usage");
}
Auth *
getauth(char *name, char *windom, char *keyp, int secmode, uchar *chal, int len)
{
int i;
Auth *ap;
if(name == nil){
name = DEF_AUTH;
if((secmode & SECMODE_PW_ENCRYPT) == 0)
sysfatal("plaintext authentication required, use '-a plain'");
}
ap = nil;
for(i = 0; i < nelem(methods); i++)
if(strcmp(methods[i].name, name) == 0){
ap = methods[i].func(windom, keyp, chal, len);
break;
}
if(! ap){
fprint(2, "%s: %s - unknown auth method\n", argv0, name);
autherr(); /* never returns */
}
return ap;
}
static int
genmac(uchar *buf, int len, int seq, uchar key[MACkeylen], uchar ours[MAClen])
{
DigestState *ds;
uchar *sig, digest[MD5dlen], theirs[MAClen];
sig = buf+MACoff;
memcpy(theirs, sig, MAClen);
memset(sig, 0, MAClen);
sig[0] = seq;
sig[1] = seq >> 8;
sig[2] = seq >> 16;
sig[3] = seq >> 24;
ds = md5(key, MACkeylen, nil, nil);
md5(buf, len, digest, ds);
memcpy(ours, digest, MAClen);
return memcmp(theirs, ours, MAClen);
}
int
macsign(Pkt *p, int seq)
{
int rc, len;
uchar *sig, *buf, mac[MAClen];
sig = p->buf + NBHDRLEN + MACoff;
buf = p->buf + NBHDRLEN;
len = (p->pos - p->buf) - NBHDRLEN;
#ifdef DEBUG_MAC
if(seq & 1)
dmp("rx", seq, sig, MAClen);
#endif
rc = 0;
if(! p->s->seqrun)
memcpy(mac, "BSRSPYL ", 8); /* no idea, ask MS */
else
rc = genmac(buf, len, seq, p->s->auth->mackey[0], mac);
#ifdef DEBUG_MAC
if(!(seq & 1))
dmp("tx", seq, mac, MAClen);
#endif
memcpy(sig, mac, MAClen);
return rc;
}
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