ref: cdcc2bf6944fa9f0765a5c3c990eb6b0b12b605d
dir: /cpu.c/
/*
* cpu.c - Make a connection to a cpu server
*
* Invoked by listen as 'cpu -R | -N service net netdir'
* by users as 'cpu [-h system] [-c cmd args ...]'
*/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <authsrv.h>
#include <libsec.h>
#include "args.h"
#include "drawterm.h"
#define Maxfdata 8192
#define MaxStr 128
static void fatal(int, char*, ...);
static void usage(void);
static void writestr(int, char*, char*, int);
static int readstr(int, char*, int);
static char *rexcall(int*, char*, char*);
static char *keyspec = "";
static AuthInfo *p9any(int);
#define system csystem
static char *system;
static int cflag;
extern int dbg;
static char *srvname = "ncpu";
static char *ealgs = "rc4_256 sha1";
/* message size for exportfs; may be larger so we can do big graphics in CPU window */
static int msgsize = Maxfdata+IOHDRSZ;
/* authentication mechanisms */
static int p9auth(int);
char *authserver;
void
exits(char *s)
{
print("\ngoodbye\n");
for(;;) osyield();
}
void
usage(void)
{
fprint(2, "usage: drawterm [-a authserver] [-c cpuserver] [-s secstore] [-u user] [-r root]\n");
exits("usage");
}
int fdd;
int
mountfactotum(void)
{
int fd;
if((fd = dialfactotum()) < 0)
return -1;
if(sysmount(fd, -1, "/mnt/factotum", MREPL, "") < 0){
fprint(2, "mount factotum: %r\n");
return -1;
}
if((fd = open("/mnt/factotum/ctl", OREAD)) < 0){
fprint(2, "open /mnt/factotum/ctl: %r\n");
return -1;
}
close(fd);
return 0;
}
void
rcpu(char *host)
{
static char script[] =
"mount -nc /fd/0 /mnt/term || exit\n"
"bind -q /mnt/term/dev/cons /dev/cons\n"
"</dev/cons >/dev/cons >[2=1] aux/kbdfs -dq -m /mnt/term/dev\n"
"bind -q /mnt/term/dev/cons /dev/cons\n"
"</dev/cons >/dev/cons >[2=1] service=cpu exec rc -li\n";
AuthInfo *ai;
TLSconn *conn;
char *na;
int fd;
na = netmkaddr(host, "tcp", "17019");
if((fd = dial(na, 0, 0, 0)) < 0)
return;
/* provide /dev/kbd for kbdfs */
if(bind("#b", "/dev", MAFTER) < 0)
panic("bind #b: %r");
ai = p9any(fd);
if(ai == nil)
fatal(1, "can't authenticate");
conn = mallocz(sizeof(TLSconn), 1);
conn->pskID = "p9secret";
conn->psk = ai->secret;
conn->psklen = ai->nsecret;
fd = tlsClient(fd, conn);
if(fd < 0)
fatal(1, "tlsClient");
auth_freeAI(ai);
if(fprint(fd, "%7ld\n%s", strlen(script), script) < 0)
fatal(1, "sending script");
/* Begin serving the namespace */
exportfs(fd, msgsize);
fatal(1, "starting exportfs");
}
void
cpumain(int argc, char **argv)
{
char dat[MaxStr], buf[MaxStr], cmd[MaxStr], *err, *secstoreserver, *p, *s;
int fd, ms, data;
/* see if we should use a larger message size */
fd = open("/dev/draw", OREAD);
if(fd > 0){
ms = iounit(fd);
if(msgsize < ms+IOHDRSZ)
msgsize = ms+IOHDRSZ;
close(fd);
}
user = getenv("USER");
secstoreserver = nil;
authserver = getenv("auth");
system = getenv("cpu");
ARGBEGIN{
case 'a':
authserver = EARGF(usage());
break;
case 'c':
system = EARGF(usage());
break;
case 'd':
dbg++;
break;
case 'e':
ealgs = EARGF(usage());
if(*ealgs == 0 || strcmp(ealgs, "clear") == 0)
ealgs = nil;
break;
case 'r':
snprint(buf, sizeof(buf), "/root/%s", EARGF(usage()));
cleanname(buf);
if(bind(buf, "/root", MREPL) < 0)
panic("bind /root: %r");
break;
case 'C':
cflag++;
cmd[0] = '!';
cmd[1] = '\0';
while((p = ARGF()) != nil) {
strcat(cmd, " ");
strcat(cmd, p);
}
break;
case 'k':
keyspec = EARGF(usage());
break;
case 's':
secstoreserver = EARGF(usage());
break;
case 'u':
user = EARGF(usage());
break;
default:
usage();
}ARGEND;
if(argc != 0)
usage();
if(bind("/root", "/", MAFTER) < 0)
panic("bind /root: %r");
if(system == nil)
system = readcons("cpu", "cpu", 0);
if(user == nil)
user = readcons("user", "glenda", 0);
if(authserver == nil)
authserver = readcons("auth", system, 0);
if(mountfactotum() < 0){
if(secstoreserver == nil)
secstoreserver = authserver;
if(havesecstore(secstoreserver, user)){
s = secstorefetch(secstoreserver, user, nil);
if(s){
if(strlen(s) >= sizeof secstorebuf)
sysfatal("secstore data too big");
strcpy(secstorebuf, s);
}
}
}
rcpu(system);
if((err = rexcall(&data, system, srvname)))
fatal(1, "%s: %s", err, system);
/* Tell the remote side the command to execute and where our working directory is */
if(cflag)
writestr(data, cmd, "command", 0);
if(getcwd(dat, sizeof(dat)) == 0)
writestr(data, "NO", "dir", 0);
else
writestr(data, dat, "dir", 0);
/*
* Wait for the other end to execute and start our file service
* of /mnt/term
*/
if(readstr(data, buf, sizeof(buf)) < 0)
fatal(1, "waiting for FS: %r");
if(strncmp("FS", buf, 2) != 0) {
print("remote cpu: %s", buf);
exits(buf);
}
if(readstr(data, buf, sizeof buf) < 0)
fatal(1, "waiting for remote export: %r");
if(strcmp(buf, "/") != 0){
print("remote cpu: %s" , buf);
exits(buf);
}
write(data, "OK", 2);
/* Begin serving the gnot namespace */
exportfs(data, msgsize);
fatal(1, "starting exportfs");
}
void
fatal(int syserr, char *fmt, ...)
{
Fmt f;
char *str;
va_list arg;
fmtstrinit(&f);
fmtprint(&f, "cpu: ");
va_start(arg, fmt);
fmtvprint(&f, fmt, arg);
va_end(arg);
if(syserr)
fmtprint(&f, ": %r");
fmtprint(&f, "\n");
str = fmtstrflush(&f);
write(2, str, strlen(str));
exits(str);
}
char *negstr = "negotiating authentication method";
char*
rexcall(int *fd, char *host, char *service)
{
char *na;
char dir[MaxStr];
char err[ERRMAX];
char msg[MaxStr];
int n;
na = netmkaddr(host, "tcp", "17010");
if((*fd = dial(na, 0, dir, 0)) < 0)
return "can't dial";
/* negotiate authentication mechanism */
strcpy(msg, "p9any");
if(ealgs != nil){
strcat(msg, " ");
strcat(msg, ealgs);
}
writestr(*fd, msg, negstr, 0);
n = readstr(*fd, err, sizeof err);
if(n < 0)
return negstr;
if(*err){
werrstr(err);
return negstr;
}
/* authenticate */
*fd = p9auth(*fd);
if(*fd < 0)
return "can't authenticate";
return 0;
}
void
writestr(int fd, char *str, char *thing, int ignore)
{
int l, n;
l = strlen(str);
n = write(fd, str, l+1);
if(!ignore && n < 0)
fatal(1, "writing network: %s", thing);
}
int
readstr(int fd, char *str, int len)
{
int n;
while(len) {
n = read(fd, str, 1);
if(n < 0)
return -1;
if(*str == '\0')
return 0;
str++;
len--;
}
return -1;
}
static void
mksecret(char *t, uchar *f)
{
sprint(t, "%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux",
f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
}
/*
* plan9 authentication followed by rc4 encryption
*/
static int
p9auth(int fd)
{
uchar key[16];
uchar digest[SHA1dlen];
char fromclientsecret[21];
char fromserversecret[21];
int i;
AuthInfo *ai;
ai = p9any(fd);
if(ai == nil)
return -1;
if(ealgs == nil)
return fd;
if(ai->nsecret < 8){
werrstr("secret too small");
return -1;
}
memmove(key+4, ai->secret, 8);
/* exchange random numbers */
genrandom(key, 4);
if(write(fd, key, 4) != 4)
return -1;
if(readn(fd, key+12, 4) != 4)
return -1;
/* scramble into two secrets */
sha1(key, sizeof(key), digest, nil);
mksecret(fromclientsecret, digest);
mksecret(fromserversecret, digest+10);
/* set up encryption */
i = pushssl(fd, ealgs, fromclientsecret, fromserversecret, nil);
if(i < 0)
werrstr("can't establish ssl connection: %r");
return i;
}
int
authdial(char *net, char *dom)
{
int fd;
fd = dial(netmkaddr(authserver, "tcp", "567"), 0, 0, 0);
//print("authdial %d\n", fd);
return fd;
}
static int
getastickets(Authkey *key, Ticketreq *tr, uchar *y, char *tbuf, int tbuflen)
{
int asfd, rv;
char *dom;
dom = tr->authdom;
asfd = authdial(nil, dom);
if(asfd < 0)
return -1;
if(y != nil){
PAKpriv p;
rv = -1;
tr->type = AuthPAK;
if(_asrequest(asfd, tr) != 0 || write(asfd, y, PAKYLEN) != PAKYLEN)
goto Out;
authpak_new(&p, key, (uchar*)tbuf, 1);
if(write(asfd, tbuf, PAKYLEN) != PAKYLEN)
goto Out;
if(_asrdresp(asfd, tbuf, 2*PAKYLEN) != 2*PAKYLEN)
goto Out;
memmove(y, tbuf, PAKYLEN);
if(authpak_finish(&p, key, (uchar*)tbuf+PAKYLEN))
goto Out;
}
tr->type = AuthTreq;
rv = _asgetticket(asfd, tr, tbuf, tbuflen);
Out:
close(asfd);
return rv;
}
static int
mkservertickets(Authkey *key, Ticketreq *tr, uchar *y, char *tbuf, int tbuflen)
{
Ticket t;
int ret;
if(strcmp(tr->authid, tr->hostid) != 0)
return -1;
memset(&t, 0, sizeof(t));
ret = 0;
if(y != nil){
PAKpriv p;
t.form = 1;
memmove(tbuf, y, PAKYLEN);
authpak_new(&p, key, y, 0);
authpak_finish(&p, key, (uchar*)tbuf);
}
memmove(t.chal, tr->chal, CHALLEN);
strcpy(t.cuid, tr->uid);
strcpy(t.suid, tr->uid);
genrandom((uchar*)t.key, sizeof(t.key));
t.num = AuthTc;
ret += convT2M(&t, tbuf+ret, tbuflen-ret, key);
t.num = AuthTs;
ret += convT2M(&t, tbuf+ret, tbuflen-ret, key);
memset(&t, 0, sizeof(t));
return ret;
}
static int
gettickets(Authkey *key, Ticketreq *tr, uchar *y, char *tbuf, int tbuflen)
{
int ret;
ret = getastickets(key, tr, y, tbuf, tbuflen);
if(ret > 0)
return ret;
return mkservertickets(key, tr, y, tbuf, tbuflen);
}
/*
* prompt user for a key. don't care about memory leaks, runs standalone
*/
static Attr*
promptforkey(char *params)
{
char *v;
int fd;
Attr *a, *attr;
char *def;
fd = open("/dev/cons", ORDWR);
if(fd < 0)
sysfatal("opening /dev/cons: %r");
attr = _parseattr(params);
fprint(fd, "\n!Adding key:");
for(a=attr; a; a=a->next)
if(a->type != AttrQuery && a->name[0] != '!')
fprint(fd, " %q=%q", a->name, a->val);
fprint(fd, "\n");
for(a=attr; a; a=a->next){
v = a->name;
if(a->type != AttrQuery || v[0]=='!')
continue;
def = nil;
if(strcmp(v, "user") == 0)
def = getuser();
a->val = readcons(v, def, 0);
if(a->val == nil)
sysfatal("user terminated key input");
a->type = AttrNameval;
}
for(a=attr; a; a=a->next){
v = a->name;
if(a->type != AttrQuery || v[0]!='!')
continue;
def = nil;
if(strcmp(v+1, "user") == 0)
def = getuser();
a->val = readcons(v+1, def, 1);
if(a->val == nil)
sysfatal("user terminated key input");
a->type = AttrNameval;
}
fprint(fd, "!\n");
close(fd);
return attr;
}
/*
* send a key to the mounted factotum
*/
static int
sendkey(Attr *attr)
{
int fd, rv;
char buf[1024];
fd = open("/mnt/factotum/ctl", ORDWR);
if(fd < 0)
sysfatal("opening /mnt/factotum/ctl: %r");
rv = fprint(fd, "key %A\n", attr);
read(fd, buf, sizeof buf);
close(fd);
return rv;
}
int
askuser(char *params)
{
Attr *attr;
fmtinstall('A', _attrfmt);
attr = promptforkey(params);
if(attr == nil)
sysfatal("no key supplied");
if(sendkey(attr) < 0)
sysfatal("sending key to factotum: %r");
return 0;
}
AuthInfo*
p9anyfactotum(int fd, int afd)
{
return auth_proxy(fd, askuser, "proto=p9any role=client %s", keyspec);
}
AuthInfo*
p9any(int fd)
{
char buf[1024], buf2[1024], *bbuf, *p, *proto, *dom, *u;
char *pass;
uchar crand[2*NONCELEN], cchal[CHALLEN], y[PAKYLEN];
char tbuf[2*MAXTICKETLEN+MAXAUTHENTLEN+PAKYLEN], trbuf[TICKREQLEN+PAKYLEN];
Authkey authkey;
Authenticator auth;
int afd, i, n, m, v2, dp9ik;
Ticketreq tr;
Ticket t;
AuthInfo *ai;
if((afd = open("/mnt/factotum/ctl", ORDWR)) >= 0)
return p9anyfactotum(fd, afd);
werrstr("");
if(readstr(fd, buf, sizeof buf) < 0)
fatal(1, "cannot read p9any negotiation");
bbuf = buf;
v2 = 0;
if(strncmp(buf, "v.2 ", 4) == 0){
v2 = 1;
bbuf += 4;
}
dp9ik = 0;
proto = nil;
while(bbuf != nil){
if((p = strchr(bbuf, ' ')))
*p++ = 0;
if((dom = strchr(bbuf, '@')) == nil)
fatal(1, "bad p9any domain");
*dom++ = 0;
if(strcmp(bbuf, "p9sk1") == 0 || strcmp(bbuf, "dp9ik") == 0){
proto = bbuf;
if(strcmp(proto, "dp9ik") == 0){
dp9ik = 1;
break;
}
}
bbuf = p;
}
if(proto == nil)
fatal(1, "server did not offer p9sk1 or dp9ik");
proto = estrdup(proto);
sprint(buf2, "%s %s", proto, dom);
if(write(fd, buf2, strlen(buf2)+1) != strlen(buf2)+1)
fatal(1, "cannot write user/domain choice in p9any");
if(v2){
if(readstr(fd, buf, sizeof buf) < 0)
fatal(1, "cannot read OK in p9any: got %d %s", n, buf);
if(memcmp(buf, "OK\0", 3) != 0)
fatal(1, "did not get OK in p9any");
}
genrandom(crand, 2*NONCELEN);
genrandom(cchal, CHALLEN);
if(write(fd, cchal, CHALLEN) != CHALLEN)
fatal(1, "cannot write p9sk1 challenge");
n = TICKREQLEN;
if(dp9ik)
n += PAKYLEN;
if(readn(fd, trbuf, n) != n || convM2TR(trbuf, TICKREQLEN, &tr) <= 0)
fatal(1, "cannot read ticket request in p9sk1");
u = user;
pass = findkey(&u, tr.authdom, proto);
memset(secstorebuf, 0, sizeof(secstorebuf)); /* forget secstore secrets */
if(pass == nil)
again:
pass = getkey(u, tr.authdom, proto);
if(pass == nil)
fatal(1, "no password");
passtokey(&authkey, pass);
memset(pass, 0, strlen(pass));
free(pass);
strecpy(tr.hostid, tr.hostid+sizeof tr.hostid, u);
strecpy(tr.uid, tr.uid+sizeof tr.uid, u);
if(dp9ik){
authpak_hash(&authkey, tr.hostid);
memmove(y, trbuf+TICKREQLEN, PAKYLEN);
n = gettickets(&authkey, &tr, y, tbuf, sizeof(tbuf));
} else {
n = gettickets(&authkey, &tr, nil, tbuf, sizeof(tbuf));
}
if(n <= 0)
fatal(1, "cannot get auth tickets in p9sk1");
m = convM2T(tbuf, n, &t, &authkey);
if(m <= 0 || t.num != AuthTc){
print("?password mismatch with auth server\n");
goto again;
}
n -= m;
memmove(tbuf, tbuf+m, n);
if(dp9ik && write(fd, y, PAKYLEN) != PAKYLEN)
fatal(1, "cannot send authpak public key back");
auth.num = AuthAc;
memmove(auth.rand, crand, NONCELEN);
memmove(auth.chal, tr.chal, CHALLEN);
m = convA2M(&auth, tbuf+n, sizeof(tbuf)-n, &t);
n += m;
if(write(fd, tbuf, n) != n)
fatal(1, "cannot send ticket and authenticator back");
if((n=readn(fd, tbuf, m)) != m || memcmp(tbuf, "cpu:", 4) == 0){
if(n <= 4)
fatal(1, "cannot read authenticator");
/*
* didn't send back authenticator:
* sent back fatal error message.
*/
memmove(buf, tbuf, n);
i = readn(fd, buf+n, sizeof buf-n-1);
if(i > 0)
n += i;
buf[n] = 0;
werrstr("");
fatal(0, "server says: %s", buf);
}
if(convM2A(tbuf, n, &auth, &t) <= 0
|| auth.num != AuthAs || tsmemcmp(auth.chal, cchal, CHALLEN) != 0){
print("?you and auth server agree about password.\n");
print("?server is confused.\n");
fatal(0, "server lies got %llux want %llux", *(vlong*)auth.chal, *(vlong*)cchal);
}
memmove(crand+NONCELEN, auth.rand, NONCELEN);
// print("i am %s there.\n", t.suid);
ai = mallocz(sizeof(AuthInfo), 1);
ai->suid = estrdup(t.suid);
ai->cuid = estrdup(t.cuid);
if(dp9ik){
static char info[] = "Plan 9 session secret";
ai->nsecret = 256;
ai->secret = mallocz(ai->nsecret, 1);
hkdf_x( crand, 2*NONCELEN,
(uchar*)info, sizeof(info)-1,
(uchar*)t.key, NONCELEN,
ai->secret, ai->nsecret,
hmac_sha2_256, SHA2_256dlen);
} else {
ai->nsecret = 8;
ai->secret = mallocz(ai->nsecret, 1);
des56to64((uchar*)t.key, ai->secret);
}
memset(&t, 0, sizeof(t));
memset(&auth, 0, sizeof(auth));
memset(&authkey, 0, sizeof(authkey));
memset(cchal, 0, sizeof(cchal));
memset(crand, 0, sizeof(crand));
free(proto);
return ai;
}