ref: 042f98784acb9f09013f65b0c93b7f56e1b8a10a
dir: /sys/src/cmd/ssh.c/
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#include <auth.h>
#include <authsrv.h>
enum {
MSG_DISCONNECT = 1,
MSG_IGNORE,
MSG_UNIMPLEMENTED,
MSG_DEBUG,
MSG_SERVICE_REQUEST,
MSG_SERVICE_ACCEPT,
MSG_KEXINIT = 20,
MSG_NEWKEYS,
MSG_ECDH_INIT = 30,
MSG_ECDH_REPLY,
MSG_USERAUTH_REQUEST = 50,
MSG_USERAUTH_FAILURE,
MSG_USERAUTH_SUCCESS,
MSG_USERAUTH_BANNER,
MSG_USERAUTH_PK_OK = 60,
MSG_USERAUTH_INFO_REQUEST = 60,
MSG_USERAUTH_INFO_RESPONSE = 61,
MSG_GLOBAL_REQUEST = 80,
MSG_REQUEST_SUCCESS,
MSG_REQUEST_FAILURE,
MSG_CHANNEL_OPEN = 90,
MSG_CHANNEL_OPEN_CONFIRMATION,
MSG_CHANNEL_OPEN_FAILURE,
MSG_CHANNEL_WINDOW_ADJUST,
MSG_CHANNEL_DATA,
MSG_CHANNEL_EXTENDED_DATA,
MSG_CHANNEL_EOF,
MSG_CHANNEL_CLOSE,
MSG_CHANNEL_REQUEST,
MSG_CHANNEL_SUCCESS,
MSG_CHANNEL_FAILURE,
};
enum {
Overhead = 256, // enougth for MSG_CHANNEL_DATA header
MaxPacket = 1<<15,
WinPackets = 8, // (1<<15) * 8 = 256K
};
int MaxPwTries = 3; // retry this often for keyboard-interactive
typedef struct
{
u32int seq;
u32int kex;
u32int chan;
int win;
int pkt;
int eof;
Chachastate cs1;
Chachastate cs2;
uchar *r;
uchar *w;
uchar b[Overhead + MaxPacket];
char *v;
int pid;
Rendez;
} Oneway;
int nsid;
uchar sid[256];
char thumb[2*SHA2_256dlen+1], *thumbfile;
int fd, intr, raw, debug;
char *user, *service, *status, *host, *cmd;
Oneway recv, send;
void dispatch(void);
void
shutdown(void)
{
recv.eof = send.eof = 1;
if(send.pid > 0)
postnote(PNPROC, send.pid, "shutdown");
}
void
catch(void*, char *msg)
{
if(strstr(msg, "interrupt") != nil){
intr = 1;
noted(NCONT);
}
noted(NDFLT);
}
int
wasintr(void)
{
char err[ERRMAX];
int r;
if(intr)
return 1;
memset(err, 0, sizeof(err));
errstr(err, sizeof(err));
r = strstr(err, "interrupt") != nil;
errstr(err, sizeof(err));
return r;
}
#define PUT4(p, u) (p)[0] = (u)>>24, (p)[1] = (u)>>16, (p)[2] = (u)>>8, (p)[3] = (u)
#define GET4(p) (u32int)(p)[3] | (u32int)(p)[2]<<8 | (u32int)(p)[1]<<16 | (u32int)(p)[0]<<24
int
vpack(uchar *p, int n, char *fmt, va_list a)
{
uchar *p0 = p, *e = p+n;
u32int u;
mpint *m;
void *s;
int c;
for(;;){
switch(c = *fmt++){
case '\0':
return p - p0;
case '_':
if(++p > e) goto err;
break;
case '.':
*va_arg(a, void**) = p;
break;
case 'b':
if(p >= e) goto err;
*p++ = va_arg(a, int);
break;
case 'm':
m = va_arg(a, mpint*);
u = (mpsignif(m)+8)/8;
if(p+4 > e) goto err;
PUT4(p, u), p += 4;
if(u > e-p) goto err;
mptober(m, p, u), p += u;
break;
case '[':
case 's':
s = va_arg(a, void*);
u = va_arg(a, int);
if(c == 's'){
if(p+4 > e) goto err;
PUT4(p, u), p += 4;
}
if(u > e-p) goto err;
memmove(p, s, u);
p += u;
break;
case 'u':
u = va_arg(a, int);
if(p+4 > e) goto err;
PUT4(p, u), p += 4;
break;
}
}
err:
return -1;
}
int
vunpack(uchar *p, int n, char *fmt, va_list a)
{
uchar *p0 = p, *e = p+n;
u32int u;
mpint *m;
void *s;
for(;;){
switch(*fmt++){
case '\0':
return p - p0;
case '_':
if(++p > e) goto err;
break;
case '.':
*va_arg(a, void**) = p;
break;
case 'b':
if(p >= e) goto err;
*va_arg(a, int*) = *p++;
break;
case 'm':
if(p+4 > e) goto err;
u = GET4(p), p += 4;
if(u > e-p) goto err;
m = va_arg(a, mpint*);
betomp(p, u, m), p += u;
break;
case 's':
if(p+4 > e) goto err;
u = GET4(p), p += 4;
if(u > e-p) goto err;
*va_arg(a, void**) = p;
*va_arg(a, int*) = u;
p += u;
break;
case '[':
s = va_arg(a, void*);
u = va_arg(a, int);
if(u > e-p) goto err;
memmove(s, p, u);
p += u;
break;
case 'u':
if(p+4 > e) goto err;
u = GET4(p);
*va_arg(a, int*) = u;
p += 4;
break;
}
}
err:
return -1;
}
int
pack(uchar *p, int n, char *fmt, ...)
{
va_list a;
va_start(a, fmt);
n = vpack(p, n, fmt, a);
va_end(a);
return n;
}
int
unpack(uchar *p, int n, char *fmt, ...)
{
va_list a;
va_start(a, fmt);
n = vunpack(p, n, fmt, a);
va_end(a);
return n;
}
void
setupcs(Oneway *c, uchar otk[32])
{
uchar iv[8];
memset(otk, 0, 32);
pack(iv, sizeof(iv), "uu", 0, c->seq);
chacha_setiv(&c->cs1, iv);
chacha_setiv(&c->cs2, iv);
chacha_setblock(&c->cs1, 0);
chacha_setblock(&c->cs2, 0);
chacha_encrypt(otk, 32, &c->cs2);
}
void
sendpkt(char *fmt, ...)
{
static uchar buf[sizeof(send.b)];
int n, pad;
va_list a;
va_start(a, fmt);
n = vpack(send.b, sizeof(send.b), fmt, a);
va_end(a);
if(n < 0) {
toobig: sysfatal("sendpkt: message too big");
return;
}
send.r = send.b;
send.w = send.b+n;
if(debug > 1)
fprint(2, "sendpkt: (%d) %.*H\n", send.r[0], (int)(send.w-send.r), send.r);
if(nsid){
/* undocumented */
pad = ChachaBsize - ((5+n) % ChachaBsize) + 4;
} else {
for(pad=4; (5+n+pad) % 8; pad++)
;
}
prng(send.w, pad);
n = pack(buf, sizeof(buf)-16, "ub[[", 1+n+pad, pad, send.b, n, send.w, pad);
if(n < 0) goto toobig;
if(nsid){
uchar otk[32];
setupcs(&send, otk);
chacha_encrypt(buf, 4, &send.cs1);
chacha_encrypt(buf+4, n-4, &send.cs2);
poly1305(buf, n, otk, sizeof(otk), buf+n, nil);
n += 16;
}
if(write(fd, buf, n) != n)
sysfatal("write: %r");
send.seq++;
}
int
readall(int fd, uchar *data, int len)
{
int n, tot;
for(tot = 0; tot < len; tot += n){
n = read(fd, data+tot, len-tot);
if(n <= 0){
if(n < 0 && wasintr()){
n = 0;
continue;
} else if(n == 0)
werrstr("eof");
break;
}
}
return tot;
}
int
recvpkt(void)
{
uchar otk[32], tag[16];
DigestState *ds = nil;
int n;
if(readall(fd, recv.b, 4) != 4)
sysfatal("read1: %r");
if(nsid){
setupcs(&recv, otk);
ds = poly1305(recv.b, 4, otk, sizeof(otk), nil, nil);
chacha_encrypt(recv.b, 4, &recv.cs1);
unpack(recv.b, 4, "u", &n);
n += 16;
} else {
unpack(recv.b, 4, "u", &n);
}
if(n < 8 || n > sizeof(recv.b)){
badlen: sysfatal("bad length %d", n);
}
if(readall(fd, recv.b, n) != n)
sysfatal("read2: %r");
if(nsid){
n -= 16;
if(n < 0) goto badlen;
poly1305(recv.b, n, otk, sizeof(otk), tag, ds);
if(tsmemcmp(tag, recv.b+n, 16) != 0)
sysfatal("bad tag");
chacha_encrypt(recv.b, n, &recv.cs2);
}
n -= recv.b[0]+1;
if(n < 1) goto badlen;
recv.r = recv.b + 1;
recv.w = recv.r + n;
recv.seq++;
if(debug > 1)
fprint(2, "recvpkt: (%d) %.*H\n", recv.r[0], (int)(recv.w-recv.r), recv.r);
return recv.r[0];
}
static char sshrsa[] = "ssh-rsa";
int
rsapub2ssh(RSApub *rsa, uchar *data, int len)
{
return pack(data, len, "smm", sshrsa, sizeof(sshrsa)-1, rsa->ek, rsa->n);
}
RSApub*
ssh2rsapub(uchar *data, int len)
{
RSApub *pub;
char *s;
int n;
pub = rsapuballoc();
pub->n = mpnew(0);
pub->ek = mpnew(0);
if(unpack(data, len, "smm", &s, &n, pub->ek, pub->n) < 0
|| n != sizeof(sshrsa)-1 || memcmp(s, sshrsa, n) != 0){
rsapubfree(pub);
return nil;
}
return pub;
}
int
rsasig2ssh(RSApub *pub, mpint *S, uchar *data, int len)
{
int l = (mpsignif(pub->n)+7)/8;
if(4+7+4+l > len)
return -1;
mptober(S, data+4+7+4, l);
return pack(data, len, "ss", sshrsa, sizeof(sshrsa)-1, data+4+7+4, l);
}
mpint*
ssh2rsasig(uchar *data, int len)
{
mpint *m;
char *s;
int n;
m = mpnew(0);
if(unpack(data, len, "sm", &s, &n, m) < 0
|| n != sizeof(sshrsa)-1 || memcmp(s, sshrsa, n) != 0){
mpfree(m);
return nil;
}
return m;
}
/* libsec */
extern mpint* pkcs1padbuf(uchar *buf, int len, mpint *modulus, int blocktype);
extern int asn1encodedigest(DigestState* (*fun)(uchar*, ulong, uchar*, DigestState*),
uchar *digest, uchar *buf, int len);
mpint*
pkcs1digest(uchar *data, int len, RSApub *pub)
{
uchar digest[SHA1dlen], buf[256];
sha1(data, len, digest, nil);
return pkcs1padbuf(buf, asn1encodedigest(sha1, digest, buf, sizeof(buf)), pub->n, 1);
}
int
pkcs1verify(uchar *data, int len, RSApub *pub, mpint *S)
{
mpint *V;
int ret;
V = pkcs1digest(data, len, pub);
ret = V != nil;
if(ret){
rsaencrypt(pub, S, S);
ret = mpcmp(V, S) == 0;
mpfree(V);
}
return ret;
}
DigestState*
hashstr(void *data, ulong len, DigestState *ds)
{
uchar l[4];
pack(l, 4, "u", len);
return sha2_256((uchar*)data, len, nil, sha2_256(l, 4, nil, ds));
}
void
kdf(uchar *k, int nk, uchar *h, char x, uchar *out, int len)
{
uchar digest[SHA2_256dlen], *out0;
DigestState *ds;
int n;
ds = hashstr(k, nk, nil);
ds = sha2_256(h, sizeof(digest), nil, ds);
ds = sha2_256((uchar*)&x, 1, nil, ds);
sha2_256(sid, nsid, digest, ds);
for(out0=out;;){
n = len;
if(n > sizeof(digest))
n = sizeof(digest);
memmove(out, digest, n);
len -= n;
if(len == 0)
break;
out += n;
ds = hashstr(k, nk, nil);
ds = sha2_256(h, sizeof(digest), nil, ds);
sha2_256(out0, out-out0, digest, ds);
}
}
void
kex(int gotkexinit)
{
static char kexalgs[] = "curve25519-sha256,[email protected]";
static char cipheralgs[] = "[email protected]";
static char zipalgs[] = "none";
static char macalgs[] = "";
static char langs[] = "";
uchar cookie[16], x[32], yc[32], z[32], k[32+1], h[SHA2_256dlen], *ys, *ks, *sig;
uchar k12[2*ChachaKeylen];
int i, nk, nys, nks, nsig;
DigestState *ds;
mpint *S, *K;
RSApub *pub;
ds = hashstr(send.v, strlen(send.v), nil);
ds = hashstr(recv.v, strlen(recv.v), ds);
genrandom(cookie, sizeof(cookie));
sendpkt("b[ssssssssssbu", MSG_KEXINIT,
cookie, sizeof(cookie),
kexalgs, sizeof(kexalgs)-1,
sshrsa, sizeof(sshrsa)-1,
cipheralgs, sizeof(cipheralgs)-1,
cipheralgs, sizeof(cipheralgs)-1,
macalgs, sizeof(macalgs)-1,
macalgs, sizeof(macalgs)-1,
zipalgs, sizeof(zipalgs)-1,
zipalgs, sizeof(zipalgs)-1,
langs, sizeof(langs)-1,
langs, sizeof(langs)-1,
0,
0);
ds = hashstr(send.r, send.w-send.r, ds);
if(!gotkexinit){
Next0: switch(recvpkt()){
default:
dispatch();
goto Next0;
case MSG_KEXINIT:
break;
}
}
ds = hashstr(recv.r, recv.w-recv.r, ds);
if(debug){
char *tab[] = {
"kexalgs", "hostalgs",
"cipher1", "cipher2",
"mac1", "mac2",
"zip1", "zip2",
"lang1", "lang2",
nil,
}, **t, *s;
uchar *p = recv.r+17;
int n;
for(t=tab; *t != nil; t++){
if(unpack(p, recv.w-p, "s.", &s, &n, &p) < 0)
break;
fprint(2, "%s: %.*s\n", *t, n, s);
}
}
curve25519_dh_new(x, yc);
yc[31] &= ~0x80;
sendpkt("bs", MSG_ECDH_INIT, yc, sizeof(yc));
Next1: switch(recvpkt()){
default:
dispatch();
goto Next1;
case MSG_KEXINIT:
sysfatal("inception");
case MSG_ECDH_REPLY:
if(unpack(recv.r, recv.w-recv.r, "_sss", &ks, &nks, &ys, &nys, &sig, &nsig) < 0)
sysfatal("bad ECDH_REPLY");
break;
}
if(nys != 32)
sysfatal("bad server ECDH ephermal public key length");
ds = hashstr(ks, nks, ds);
ds = hashstr(yc, 32, ds);
ds = hashstr(ys, 32, ds);
if(thumb[0] == 0){
Thumbprint *ok;
sha2_256(ks, nks, h, nil);
i = enc64(thumb, sizeof(thumb), h, sizeof(h));
while(i > 0 && thumb[i-1] == '=')
i--;
thumb[i] = '\0';
if(debug)
fprint(2, "host fingerprint: %s\n", thumb);
ok = initThumbprints(thumbfile, nil, "ssh");
if(ok == nil || !okThumbprint(h, sizeof(h), ok)){
if(ok != nil) werrstr("unknown host");
fprint(2, "%s: %r\n", argv0);
fprint(2, "verify hostkey: %s %.*[\n", sshrsa, nks, ks);
fprint(2, "add thumbprint after verification:\n");
fprint(2, "\techo 'ssh sha256=%s server=%s' >> %q\n", thumb, host, thumbfile);
sysfatal("checking hostkey failed: %r");
}
freeThumbprints(ok);
}
if((pub = ssh2rsapub(ks, nks)) == nil)
sysfatal("bad server public key");
if((S = ssh2rsasig(sig, nsig)) == nil)
sysfatal("bad server signature");
curve25519_dh_finish(x, ys, z);
K = betomp(z, 32, nil);
nk = (mpsignif(K)+8)/8;
mptober(K, k, nk);
mpfree(K);
ds = hashstr(k, nk, ds);
sha2_256(nil, 0, h, ds);
if(!pkcs1verify(h, sizeof(h), pub, S))
sysfatal("server verification failed");
mpfree(S);
rsapubfree(pub);
sendpkt("b", MSG_NEWKEYS);
Next2: switch(recvpkt()){
default:
dispatch();
goto Next2;
case MSG_KEXINIT:
sysfatal("inception");
case MSG_NEWKEYS:
break;
}
/* next key exchange */
recv.kex = recv.seq + 100000;
send.kex = send.seq + 100000;
if(nsid == 0)
memmove(sid, h, nsid = sizeof(h));
kdf(k, nk, h, 'C', k12, sizeof(k12));
setupChachastate(&send.cs1, k12+1*ChachaKeylen, ChachaKeylen, nil, 64/8, 20);
setupChachastate(&send.cs2, k12+0*ChachaKeylen, ChachaKeylen, nil, 64/8, 20);
kdf(k, nk, h, 'D', k12, sizeof(k12));
setupChachastate(&recv.cs1, k12+1*ChachaKeylen, ChachaKeylen, nil, 64/8, 20);
setupChachastate(&recv.cs2, k12+0*ChachaKeylen, ChachaKeylen, nil, 64/8, 20);
}
static char *authnext;
int
authok(char *meth)
{
int ok = authnext == nil || strstr(authnext, meth) != nil;
if(debug)
fprint(2, "userauth %s %s\n", meth, ok ? "ok" : "skipped");
return ok;
}
int
authfailure(char *meth)
{
char *s;
int n, partial;
if(unpack(recv.r, recv.w-recv.r, "_sb", &s, &n, &partial) < 0)
sysfatal("bad auth failure response");
free(authnext);
authnext = smprint("%.*s", n, s);
if(debug)
fprint(2, "userauth %s failed: partial=%d, next=%s\n", meth, partial, authnext);
return partial != 0 || !authok(meth);
}
int
noneauth(void)
{
static char authmeth[] = "none";
if(!authok(authmeth))
return -1;
sendpkt("bsss", MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1);
Next0: switch(recvpkt()){
default:
dispatch();
goto Next0;
case MSG_USERAUTH_FAILURE:
werrstr("authentication needed");
authfailure(authmeth);
return -1;
case MSG_USERAUTH_SUCCESS:
return 0;
}
}
int
pubkeyauth(void)
{
static char authmeth[] = "publickey";
uchar pk[4096], sig[4096];
int npk, nsig;
int afd, n;
char *s;
mpint *S;
AuthRpc *rpc;
RSApub *pub;
if(!authok(authmeth))
return -1;
if((afd = open("/mnt/factotum/rpc", ORDWR)) < 0)
return -1;
if((rpc = auth_allocrpc(afd)) == nil){
close(afd);
return -1;
}
s = "proto=rsa service=ssh role=client";
if(auth_rpc(rpc, "start", s, strlen(s)) != ARok){
auth_freerpc(rpc);
close(afd);
return -1;
}
pub = rsapuballoc();
pub->n = mpnew(0);
pub->ek = mpnew(0);
while(auth_rpc(rpc, "read", nil, 0) == ARok){
s = rpc->arg;
if(strtomp(s, &s, 16, pub->n) == nil)
break;
if(*s++ != ' ')
continue;
if(strtomp(s, nil, 16, pub->ek) == nil)
continue;
npk = rsapub2ssh(pub, pk, sizeof(pk));
sendpkt("bsssbss", MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1,
0,
sshrsa, sizeof(sshrsa)-1,
pk, npk);
Next1: switch(recvpkt()){
default:
dispatch();
goto Next1;
case MSG_USERAUTH_FAILURE:
if(authfailure(authmeth))
goto Failed;
continue;
case MSG_USERAUTH_SUCCESS:
case MSG_USERAUTH_PK_OK:
break;
}
/* sign sid and the userauth request */
n = pack(send.b, sizeof(send.b), "sbsssbss",
sid, nsid,
MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1,
1,
sshrsa, sizeof(sshrsa)-1,
pk, npk);
S = pkcs1digest(send.b, n, pub);
n = snprint((char*)send.b, sizeof(send.b), "%B", S);
mpfree(S);
if(auth_rpc(rpc, "write", (char*)send.b, n) != ARok)
break;
if(auth_rpc(rpc, "read", nil, 0) != ARok)
break;
S = strtomp(rpc->arg, nil, 16, nil);
nsig = rsasig2ssh(pub, S, sig, sizeof(sig));
mpfree(S);
/* send final userauth request with the signature */
sendpkt("bsssbsss", MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1,
1,
sshrsa, sizeof(sshrsa)-1,
pk, npk,
sig, nsig);
Next2: switch(recvpkt()){
default:
dispatch();
goto Next2;
case MSG_USERAUTH_FAILURE:
if(authfailure(authmeth))
goto Failed;
continue;
case MSG_USERAUTH_SUCCESS:
break;
}
rsapubfree(pub);
auth_freerpc(rpc);
close(afd);
return 0;
}
Failed:
rsapubfree(pub);
auth_freerpc(rpc);
close(afd);
return -1;
}
int
passauth(void)
{
static char authmeth[] = "password";
UserPasswd *up;
if(!authok(authmeth))
return -1;
up = auth_getuserpasswd(auth_getkey, "proto=pass service=ssh user=%q server=%q thumb=%q",
user, host, thumb);
if(up == nil)
return -1;
sendpkt("bsssbs", MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1,
0,
up->passwd, strlen(up->passwd));
memset(up->passwd, 0, strlen(up->passwd));
free(up);
Next0: switch(recvpkt()){
default:
dispatch();
goto Next0;
case MSG_USERAUTH_FAILURE:
werrstr("wrong password");
authfailure(authmeth);
return -1;
case MSG_USERAUTH_SUCCESS:
return 0;
}
}
int
kbintauth(void)
{
static char authmeth[] = "keyboard-interactive";
int tries;
char *name, *inst, *s, *a;
int fd, i, n, m;
int nquest, echo;
uchar *ans, *answ;
tries = 0;
if(!authok(authmeth))
return -1;
Loop:
if(++tries > MaxPwTries)
return -1;
sendpkt("bsssss", MSG_USERAUTH_REQUEST,
user, strlen(user),
service, strlen(service),
authmeth, sizeof(authmeth)-1,
"", 0,
"", 0);
Next0: switch(recvpkt()){
default:
dispatch();
goto Next0;
case MSG_USERAUTH_FAILURE:
werrstr("keyboard-interactive failed");
if(authfailure(authmeth))
return -1;
goto Loop;
case MSG_USERAUTH_SUCCESS:
return 0;
case MSG_USERAUTH_INFO_REQUEST:
break;
}
Retry:
if((fd = open("/dev/cons", OWRITE)) < 0)
return -1;
if(unpack(recv.r, recv.w-recv.r, "_ss.", &name, &n, &inst, &m, &recv.r) < 0)
sysfatal("bad info request: name, inst");
while(n > 0 && strchr("\r\n\t ", name[n-1]) != nil)
n--;
while(m > 0 && strchr("\r\n\t ", inst[m-1]) != nil)
m--;
if(n > 0)
fprint(fd, "%.*s\n", n, name);
if(m > 0)
fprint(fd, "%.*s\n", m, inst);
/* lang, nprompt */
if(unpack(recv.r, recv.w-recv.r, "su.", &s, &n, &nquest, &recv.r) < 0)
sysfatal("bad info request: lang, #quest");
ans = answ = nil;
for(i = 0; i < nquest; i++){
if(unpack(recv.r, recv.w-recv.r, "sb.", &s, &n, &echo, &recv.r) < 0)
sysfatal("bad info request: question [%d]", i);
while(n > 0 && strchr("\r\n\t :", s[n-1]) != nil)
n--;
s[n] = '\0';
if((a = readcons(s, nil, !echo)) == nil)
sysfatal("readcons: %r");
n = answ - ans;
m = strlen(a)+4;
if((s = realloc(ans, n + m)) == nil)
sysfatal("realloc: %r");
ans = (uchar*)s;
answ = ans+n;
answ += pack(answ, m, "s", a, m-4);
}
sendpkt("bu[", MSG_USERAUTH_INFO_RESPONSE, i, ans, answ - ans);
free(ans);
close(fd);
Next1: switch(recvpkt()){
default:
dispatch();
goto Next1;
case MSG_USERAUTH_INFO_REQUEST:
goto Retry;
case MSG_USERAUTH_FAILURE:
werrstr("keyboard-interactive failed");
if(authfailure(authmeth))
return -1;
goto Loop;
case MSG_USERAUTH_SUCCESS:
return 0;
}
}
void
dispatch(void)
{
char *s;
uchar *p;
int n, b, c;
switch(recv.r[0]){
case MSG_IGNORE:
case MSG_GLOBAL_REQUEST:
return;
case MSG_DISCONNECT:
if(unpack(recv.r, recv.w-recv.r, "_us", &c, &s, &n) < 0)
break;
sysfatal("disconnect: (%d) %.*s", c, n, s);
return;
case MSG_DEBUG:
if(unpack(recv.r, recv.w-recv.r, "__sb", &s, &n, &c) < 0)
break;
if(c != 0 || debug) fprint(2, "%s: %.*s\n", argv0, n, s);
return;
case MSG_USERAUTH_BANNER:
if(unpack(recv.r, recv.w-recv.r, "_s", &s, &n) < 0)
break;
if(raw) write(2, s, n);
return;
case MSG_CHANNEL_DATA:
if(unpack(recv.r, recv.w-recv.r, "_us", &c, &s, &n) < 0)
break;
if(c != recv.chan)
break;
if(write(1, s, n) != n)
sysfatal("write out: %r");
Winadjust:
recv.win -= n;
if(recv.win < recv.pkt){
n = WinPackets*recv.pkt;
recv.win += n;
sendpkt("buu", MSG_CHANNEL_WINDOW_ADJUST, send.chan, n);
}
return;
case MSG_CHANNEL_EXTENDED_DATA:
if(unpack(recv.r, recv.w-recv.r, "_uus", &c, &b, &s, &n) < 0)
break;
if(c != recv.chan)
break;
if(b == 1) write(2, s, n);
goto Winadjust;
case MSG_CHANNEL_WINDOW_ADJUST:
if(unpack(recv.r, recv.w-recv.r, "_uu", &c, &n) < 0)
break;
if(c != recv.chan)
break;
send.win += n;
if(send.win >= send.pkt)
rwakeup(&send);
return;
case MSG_CHANNEL_REQUEST:
if(unpack(recv.r, recv.w-recv.r, "_usb.", &c, &s, &n, &b, &p) < 0)
break;
if(c != recv.chan)
break;
if(n == 11 && memcmp(s, "exit-signal", n) == 0){
if(unpack(p, recv.w-p, "s", &s, &n) < 0)
break;
if(n != 0 && status == nil)
status = smprint("%.*s", n, s);
} else if(n == 11 && memcmp(s, "exit-status", n) == 0){
if(unpack(p, recv.w-p, "u", &n) < 0)
break;
if(n != 0 && status == nil)
status = smprint("%d", n);
} else if(debug) {
fprint(2, "%s: channel request: %.*s\n", argv0, n, s);
}
return;
case MSG_CHANNEL_EOF:
recv.eof = 1;
if(!raw) write(1, "", 0);
return;
case MSG_CHANNEL_CLOSE:
shutdown();
return;
case MSG_KEXINIT:
kex(1);
return;
}
sysfatal("got: %.*H", (int)(recv.w - recv.r), recv.r);
}
char*
readline(void)
{
uchar *p;
for(p = send.b; p < &send.b[sizeof(send.b)-1]; p++){
*p = '\0';
if(read(fd, p, 1) != 1 || *p == '\n')
break;
}
while(p >= send.b && (*p == '\n' || *p == '\r'))
*p-- = '\0';
return (char*)send.b;
}
static struct {
char *term;
int xpixels;
int ypixels;
int lines;
int cols;
} tty = {
"dumb",
0,
0,
0,
0,
};
void
rawon(void)
{
int ctl;
char *s;
close(0);
if(open("/dev/cons", OREAD) != 0)
sysfatal("open: %r");
close(1);
if(open("/dev/cons", OWRITE) != 1)
sysfatal("open: %r");
dup(1, 2);
if((ctl = open("/dev/consctl", OWRITE)) >= 0)
write(ctl, "rawon", 5);
if(s = getenv("TERM")){
tty.term = s;
if(s = getenv("XPIXELS")){
tty.xpixels = atoi(s);
free(s);
}
if(s = getenv("YPIXELS")){
tty.ypixels = atoi(s);
free(s);
}
if(s = getenv("LINES")){
tty.lines = atoi(s);
free(s);
}
if(s = getenv("COLS")){
tty.cols = atoi(s);
free(s);
}
}
}
void
usage(void)
{
fprint(2, "usage: %s [-dR] [-t thumbfile] [-u user] [user@]host [cmd]\n", argv0);
exits("usage");
}
void
main(int argc, char *argv[])
{
static QLock sl;
int b, n, c;
char *s;
quotefmtinstall();
fmtinstall('B', mpfmt);
fmtinstall('H', encodefmt);
fmtinstall('[', encodefmt);
s = getenv("TERM");
raw = s != nil && strcmp(s, "dumb") != 0;
free(s);
ARGBEGIN {
case 'd':
debug++;
break;
case 'R':
raw = 0;
break;
case 'u':
user = EARGF(usage());
break;
case 't':
thumbfile = EARGF(usage());
break;
case 'T':
MaxPwTries = strtol(EARGF(usage()), &s, 0);
if(*s != 0) usage();
break;
} ARGEND;
if(argc == 0)
usage();
host = *argv++;
if(user == nil){
s = strchr(host, '@');
if(s != nil){
*s++ = '\0';
user = host;
host = s;
}
}
for(cmd = nil; *argv != nil; argv++){
if(cmd == nil)
cmd = strdup(*argv);
else {
s = smprint("%s %q", cmd, *argv);
free(cmd);
cmd = s;
}
}
if(cmd != nil)
raw = 0;
if((fd = dial(netmkaddr(host, nil, "ssh"), nil, nil, nil)) < 0)
sysfatal("dial: %r");
send.v = "SSH-2.0-(9)";
fprint(fd, "%s\r\n", send.v);
recv.v = readline();
if(debug)
fprint(2, "server verison: %s\n", recv.v);
if(strncmp("SSH-2.0-", recv.v, 8) != 0)
sysfatal("bad server version: %s", recv.v);
recv.v = strdup(recv.v);
send.l = recv.l = &sl;
if(user == nil)
user = getuser();
if(thumbfile == nil)
thumbfile = smprint("%s/lib/sshthumbs", getenv("home"));
kex(0);
service = "ssh-connection";
sendpkt("bs", MSG_SERVICE_REQUEST, "ssh-userauth", 12);
Next0: switch(recvpkt()){
default:
dispatch();
goto Next0;
case MSG_SERVICE_ACCEPT:
break;
}
if(noneauth() < 0 && pubkeyauth() < 0 && passauth() < 0 && kbintauth() < 0)
sysfatal("auth: %r");
recv.pkt = MaxPacket;
recv.win = WinPackets*recv.pkt;
recv.chan = 0;
/* open hailing frequencies */
sendpkt("bsuuu", MSG_CHANNEL_OPEN,
"session", 7,
recv.chan,
recv.win,
recv.pkt);
Next1: switch(recvpkt()){
default:
dispatch();
goto Next1;
case MSG_CHANNEL_OPEN_FAILURE:
if(unpack(recv.r, recv.w-recv.r, "_uus", &c, &b, &s, &n) < 0)
n = strlen(s = "???");
sysfatal("channel open failure: (%d) %.*s", b, n, s);
case MSG_CHANNEL_OPEN_CONFIRMATION:
break;
}
if(unpack(recv.r, recv.w-recv.r, "_uuuu", &recv.chan, &send.chan, &send.win, &send.pkt) < 0)
sysfatal("bad channel open confirmation");
if(send.pkt <= 0 || send.pkt > MaxPacket)
send.pkt = MaxPacket;
notify(catch);
atexit(shutdown);
recv.pid = getpid();
n = rfork(RFPROC|RFMEM);
if(n < 0)
sysfatal("fork: %r");
/* parent reads and dispatches packets */
if(n > 0) {
send.pid = n;
while((send.eof|recv.eof) == 0){
recvpkt();
qlock(&sl);
dispatch();
if((int)(send.kex - send.seq) <= 0 || (int)(recv.kex - recv.seq) <= 0)
kex(0);
qunlock(&sl);
}
exits(status);
}
/* child reads input and sends packets */
qlock(&sl);
if(raw) {
rawon();
sendpkt("busbsuuuus", MSG_CHANNEL_REQUEST,
send.chan,
"pty-req", 7,
0,
tty.term, strlen(tty.term),
tty.cols,
tty.lines,
tty.xpixels,
tty.ypixels,
"", 0);
}
if(cmd == nil){
sendpkt("busb", MSG_CHANNEL_REQUEST,
send.chan,
"shell", 5,
0);
} else {
sendpkt("busbs", MSG_CHANNEL_REQUEST,
send.chan,
"exec", 4,
0,
cmd, strlen(cmd));
}
for(;;){
static uchar buf[MaxPacket];
qunlock(&sl);
n = read(0, buf, send.pkt);
qlock(&sl);
if(send.eof)
break;
if(n < 0 && wasintr()){
if(!raw) break;
sendpkt("busbs", MSG_CHANNEL_REQUEST,
send.chan,
"signal", 6,
0,
"INT", 3);
intr = 0;
continue;
}
if(n <= 0)
break;
send.win -= n;
while(send.win < 0)
rsleep(&send);
sendpkt("bus", MSG_CHANNEL_DATA,
send.chan,
buf, n);
}
if(send.eof++ == 0)
sendpkt("bu", raw ? MSG_CHANNEL_CLOSE : MSG_CHANNEL_EOF, send.chan);
qunlock(&sl);
exits(nil);
}