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/*
* SSH network file system.
* Presents remote TCP stack as /net-style file system.
*/
#include "ssh.h"
#include <bio.h>
#include <ndb.h>
#include <thread.h>
#include <fcall.h>
#include <9p.h>
int rawhack = 1;
Conn *conn;
char *remoteip = "<remote>";
char *mtpt;
Cipher *allcipher[] = {
&cipherrc4,
&cipherblowfish,
&cipher3des,
&cipherdes,
&ciphernone,
&ciphertwiddle,
};
Auth *allauth[] = {
&authpassword,
&authrsa,
&authtis,
};
char *cipherlist = "rc4 3des";
char *authlist = "rsa password tis";
Cipher*
findcipher(char *name, Cipher **list, int nlist)
{
int i;
for(i=0; i<nlist; i++)
if(strcmp(name, list[i]->name) == 0)
return list[i];
error("unknown cipher %s", name);
return nil;
}
Auth*
findauth(char *name, Auth **list, int nlist)
{
int i;
for(i=0; i<nlist; i++)
if(strcmp(name, list[i]->name) == 0)
return list[i];
error("unknown auth %s", name);
return nil;
}
void
usage(void)
{
fprint(2, "usage: sshnet [-A authlist] [-c cipherlist] [-m mtpt] [user@]hostname\n");
exits("usage");
}
int
isatty(int fd)
{
char buf[64];
buf[0] = '\0';
fd2path(fd, buf, sizeof buf);
if(strlen(buf)>=9 && strcmp(buf+strlen(buf)-9, "/dev/cons")==0)
return 1;
return 0;
}
enum
{
Qroot,
Qcs,
Qtcp,
Qclone,
Qn,
Qctl,
Qdata,
Qlocal,
Qremote,
Qstatus,
};
#define PATH(type, n) ((type)|((n)<<8))
#define TYPE(path) ((int)(path) & 0xFF)
#define NUM(path) ((uint)(path)>>8)
Channel *sshmsgchan; /* chan(Msg*) */
Channel *fsreqchan; /* chan(Req*) */
Channel *fsreqwaitchan; /* chan(nil) */
Channel *fsclunkchan; /* chan(Fid*) */
Channel *fsclunkwaitchan; /* chan(nil) */
ulong time0;
enum
{
Closed,
Dialing,
Established,
Teardown,
};
char *statestr[] = {
"Closed",
"Dialing",
"Established",
"Teardown",
};
typedef struct Client Client;
struct Client
{
int ref;
int state;
int num;
int servernum;
char *connect;
Req *rq;
Req **erq;
Msg *mq;
Msg **emq;
};
int nclient;
Client **client;
int
newclient(void)
{
int i;
Client *c;
for(i=0; i<nclient; i++)
if(client[i]->ref==0 && client[i]->state == Closed)
return i;
if(nclient%16 == 0)
client = erealloc9p(client, (nclient+16)*sizeof(client[0]));
c = emalloc9p(sizeof(Client));
memset(c, 0, sizeof(*c));
c->num = nclient;
client[nclient++] = c;
return c->num;
}
void
queuereq(Client *c, Req *r)
{
if(c->rq==nil)
c->erq = &c->rq;
*c->erq = r;
r->aux = nil;
c->erq = (Req**)&r->aux;
}
void
queuemsg(Client *c, Msg *m)
{
if(c->mq==nil)
c->emq = &c->mq;
*c->emq = m;
m->link = nil;
c->emq = (Msg**)&m->link;
}
void
matchmsgs(Client *c)
{
Req *r;
Msg *m;
int n, rm;
while(c->rq && c->mq){
r = c->rq;
c->rq = r->aux;
rm = 0;
m = c->mq;
n = r->ifcall.count;
if(n >= m->ep - m->rp){
n = m->ep - m->rp;
c->mq = m->link;
rm = 1;
}
memmove(r->ofcall.data, m->rp, n);
if(rm)
free(m);
else
m->rp += n;
r->ofcall.count = n;
respond(r, nil);
}
}
Req*
findreq(Client *c, Req *r)
{
Req **l;
for(l=&c->rq; *l; l=(Req**)&(*l)->aux){
if(*l == r){
*l = r->aux;
if(*l == nil)
c->erq = l;
return r;
}
}
return nil;
}
void
dialedclient(Client *c)
{
Req *r;
if(r=c->rq){
if(r->aux != nil)
sysfatal("more than one outstanding dial request (BUG)");
if(c->state == Established)
respond(r, nil);
else
respond(r, "connect failed");
}
c->rq = nil;
}
void
teardownclient(Client *c)
{
Msg *m;
c->state = Teardown;
m = allocmsg(conn, SSH_MSG_CHANNEL_INPUT_EOF, 4);
putlong(m, c->servernum);
sendmsg(m);
}
void
hangupclient(Client *c)
{
Req *r, *next;
Msg *m, *mnext;
c->state = Closed;
for(m=c->mq; m; m=mnext){
mnext = m->link;
free(m);
}
c->mq = nil;
for(r=c->rq; r; r=next){
next = r->aux;
respond(r, "hangup on network connection");
}
c->rq = nil;
}
void
closeclient(Client *c)
{
Msg *m, *next;
if(--c->ref)
return;
if(c->rq != nil)
sysfatal("ref count reached zero with requests pending (BUG)");
for(m=c->mq; m; m=next){
next = m->link;
free(m);
}
c->mq = nil;
if(c->state != Closed)
teardownclient(c);
}
void
sshreadproc(void *a)
{
Conn *c;
Msg *m;
c = a;
for(;;){
m = recvmsg(c, -1);
if(m == nil)
sysfatal("eof on ssh connection");
sendp(sshmsgchan, m);
}
}
typedef struct Tab Tab;
struct Tab
{
char *name;
ulong mode;
};
Tab tab[] =
{
"/", DMDIR|0555,
"cs", 0666,
"tcp", DMDIR|0555,
"clone", 0666,
nil, DMDIR|0555,
"ctl", 0666,
"data", 0666,
"local", 0444,
"remote", 0444,
"status", 0444,
};
static void
fillstat(Dir *d, uvlong path)
{
Tab *t;
memset(d, 0, sizeof(*d));
d->uid = estrdup9p("ssh");
d->gid = estrdup9p("ssh");
d->qid.path = path;
d->atime = d->mtime = time0;
t = &tab[TYPE(path)];
if(t->name)
d->name = estrdup9p(t->name);
else{
d->name = smprint("%ud", NUM(path));
if(d->name == nil)
sysfatal("out of memory");
}
d->qid.type = t->mode>>24;
d->mode = t->mode;
}
static void
fsattach(Req *r)
{
if(r->ifcall.aname && r->ifcall.aname[0]){
respond(r, "invalid attach specifier");
return;
}
r->fid->qid.path = PATH(Qroot, 0);
r->fid->qid.type = QTDIR;
r->fid->qid.vers = 0;
r->ofcall.qid = r->fid->qid;
respond(r, nil);
}
static void
fsstat(Req *r)
{
fillstat(&r->d, r->fid->qid.path);
respond(r, nil);
}
static int
rootgen(int i, Dir *d, void*)
{
i += Qroot+1;
if(i <= Qtcp){
fillstat(d, i);
return 0;
}
return -1;
}
static int
tcpgen(int i, Dir *d, void*)
{
i += Qtcp+1;
if(i < Qn){
fillstat(d, i);
return 0;
}
i -= Qn;
if(i < nclient){
fillstat(d, PATH(Qn, i));
return 0;
}
return -1;
}
static int
clientgen(int i, Dir *d, void *aux)
{
Client *c;
c = aux;
i += Qn+1;
if(i <= Qstatus){
fillstat(d, PATH(i, c->num));
return 0;
}
return -1;
}
static char*
fswalk1(Fid *fid, char *name, Qid *qid)
{
int i, n;
char buf[32];
ulong path;
path = fid->qid.path;
if(!(fid->qid.type&QTDIR))
return "walk in non-directory";
if(strcmp(name, "..") == 0){
switch(TYPE(path)){
case Qn:
qid->path = PATH(Qtcp, NUM(path));
qid->type = tab[Qtcp].mode>>24;
return nil;
case Qtcp:
qid->path = PATH(Qroot, 0);
qid->type = tab[Qroot].mode>>24;
return nil;
case Qroot:
return nil;
default:
return "bug in fswalk1";
}
}
i = TYPE(path)+1;
for(; i<nelem(tab); i++){
if(i==Qn){
n = atoi(name);
snprint(buf, sizeof buf, "%d", n);
if(n < nclient && strcmp(buf, name) == 0){
qid->path = PATH(i, n);
qid->type = tab[i].mode>>24;
return nil;
}
break;
}
if(strcmp(name, tab[i].name) == 0){
qid->path = PATH(i, NUM(path));
qid->type = tab[i].mode>>24;
return nil;
}
if(tab[i].mode&DMDIR)
break;
}
return "directory entry not found";
}
typedef struct Cs Cs;
struct Cs
{
char *resp;
int isnew;
};
static int
ndbfindport(char *p)
{
char *s, *port;
int n;
static Ndb *db;
if(*p == '\0')
return -1;
n = strtol(p, &s, 0);
if(*s == '\0')
return n;
if(db == nil){
db = ndbopen("/lib/ndb/common");
if(db == nil)
return -1;
}
port = ndbgetvalue(db, nil, "tcp", p, "port", nil);
if(port == nil)
return -1;
n = atoi(port);
free(port);
return n;
}
static void
csread(Req *r)
{
Cs *cs;
cs = r->fid->aux;
if(cs->resp==nil){
respond(r, "cs read without write");
return;
}
if(r->ifcall.offset==0){
if(!cs->isnew){
r->ofcall.count = 0;
respond(r, nil);
return;
}
cs->isnew = 0;
}
readstr(r, cs->resp);
respond(r, nil);
}
static void
cswrite(Req *r)
{
int port, nf;
char err[ERRMAX], *f[4], *s, *ns;
Cs *cs;
cs = r->fid->aux;
s = emalloc(r->ifcall.count+1);
memmove(s, r->ifcall.data, r->ifcall.count);
s[r->ifcall.count] = '\0';
nf = getfields(s, f, nelem(f), 0, "!");
if(nf != 3){
free(s);
respond(r, "can't translate");
return;
}
if(strcmp(f[0], "tcp") != 0 && strcmp(f[0], "net") != 0){
free(s);
respond(r, "unknown protocol");
return;
}
port = ndbfindport(f[2]);
if(port <= 0){
free(s);
respond(r, "no translation found");
return;
}
ns = smprint("%s/tcp/clone %s!%d", mtpt, f[1], port);
if(ns == nil){
free(s);
rerrstr(err, sizeof err);
respond(r, err);
return;
}
free(s);
free(cs->resp);
cs->resp = ns;
cs->isnew = 1;
r->ofcall.count = r->ifcall.count;
respond(r, nil);
}
static void
ctlread(Req *r, Client *c)
{
char buf[32];
sprint(buf, "%d", c->num);
readstr(r, buf);
respond(r, nil);
}
static void
ctlwrite(Req *r, Client *c)
{
char *f[3], *s;
int nf;
Msg *m;
s = emalloc(r->ifcall.count+1);
memmove(s, r->ifcall.data, r->ifcall.count);
s[r->ifcall.count] = '\0';
nf = tokenize(s, f, 3);
if(nf == 0){
free(s);
respond(r, nil);
return;
}
if(strcmp(f[0], "hangup") == 0){
if(c->state != Established)
goto Badarg;
if(nf != 1)
goto Badarg;
queuereq(c, r);
teardownclient(c);
}else if(strcmp(f[0], "connect") == 0){
if(c->state != Closed)
goto Badarg;
if(nf != 2)
goto Badarg;
c->connect = estrdup9p(f[1]);
nf = getfields(f[1], f, nelem(f), 0, "!");
if(nf != 2){
free(c->connect);
c->connect = nil;
goto Badarg;
}
c->state = Dialing;
m = allocmsg(conn, SSH_MSG_PORT_OPEN, 4+4+strlen(f[0])+4+4+strlen("localhost"));
putlong(m, c->num);
putstring(m, f[0]);
putlong(m, ndbfindport(f[1]));
putstring(m, "localhost");
queuereq(c, r);
sendmsg(m);
}else{
Badarg:
respond(r, "bad or inappropriate tcp control message");
}
free(s);
}
static void
dataread(Req *r, Client *c)
{
if(c->state != Established){
respond(r, "not connected");
return;
}
queuereq(c, r);
matchmsgs(c);
}
static void
datawrite(Req *r, Client *c)
{
Msg *m;
if(c->state != Established){
respond(r, "not connected");
return;
}
if(r->ifcall.count){
m = allocmsg(conn, SSH_MSG_CHANNEL_DATA, 4+4+r->ifcall.count);
putlong(m, c->servernum);
putlong(m, r->ifcall.count);
putbytes(m, r->ifcall.data, r->ifcall.count);
sendmsg(m);
}
r->ofcall.count = r->ifcall.count;
respond(r, nil);
}
static void
localread(Req *r)
{
char buf[128];
snprint(buf, sizeof buf, "%s!%d\n", remoteip, 0);
readstr(r, buf);
respond(r, nil);
}
static void
remoteread(Req *r, Client *c)
{
char *s;
char buf[128];
s = c->connect;
if(s == nil)
s = "::!0";
snprint(buf, sizeof buf, "%s\n", s);
readstr(r, buf);
respond(r, nil);
}
static void
statusread(Req *r, Client *c)
{
char buf[64];
char *s;
snprint(buf, sizeof buf, "%s!%d", remoteip, 0);
s = statestr[c->state];
readstr(r, s);
respond(r, nil);
}
static void
fsread(Req *r)
{
char e[ERRMAX];
ulong path;
path = r->fid->qid.path;
switch(TYPE(path)){
default:
snprint(e, sizeof e, "bug in fsread path=%lux", path);
respond(r, e);
break;
case Qroot:
dirread9p(r, rootgen, nil);
respond(r, nil);
break;
case Qcs:
csread(r);
break;
case Qtcp:
dirread9p(r, tcpgen, nil);
respond(r, nil);
break;
case Qn:
dirread9p(r, clientgen, client[NUM(path)]);
respond(r, nil);
break;
case Qctl:
ctlread(r, client[NUM(path)]);
break;
case Qdata:
dataread(r, client[NUM(path)]);
break;
case Qlocal:
localread(r);
break;
case Qremote:
remoteread(r, client[NUM(path)]);
break;
case Qstatus:
statusread(r, client[NUM(path)]);
break;
}
}
static void
fswrite(Req *r)
{
ulong path;
char e[ERRMAX];
path = r->fid->qid.path;
switch(TYPE(path)){
default:
snprint(e, sizeof e, "bug in fswrite path=%lux", path);
respond(r, e);
break;
case Qcs:
cswrite(r);
break;
case Qctl:
ctlwrite(r, client[NUM(path)]);
break;
case Qdata:
datawrite(r, client[NUM(path)]);
break;
}
}
static void
fsopen(Req *r)
{
static int need[4] = { 4, 2, 6, 1 };
ulong path;
int n;
Tab *t;
Cs *cs;
/*
* lib9p already handles the blatantly obvious.
* we just have to enforce the permissions we have set.
*/
path = r->fid->qid.path;
t = &tab[TYPE(path)];
n = need[r->ifcall.mode&3];
if((n&t->mode) != n){
respond(r, "permission denied");
return;
}
switch(TYPE(path)){
case Qcs:
cs = emalloc(sizeof(Cs));
r->fid->aux = cs;
respond(r, nil);
break;
case Qclone:
n = newclient();
path = PATH(Qctl, n);
r->fid->qid.path = path;
r->ofcall.qid.path = path;
if(chatty9p)
fprint(2, "open clone => path=%lux\n", path);
t = &tab[Qctl];
/* fall through */
default:
if(t-tab >= Qn)
client[NUM(path)]->ref++;
respond(r, nil);
break;
}
}
static void
fsflush(Req *r)
{
int i;
for(i=0; i<nclient; i++)
if(findreq(client[i], r->oldreq))
respond(r->oldreq, "interrupted");
respond(r, nil);
}
static void
handlemsg(Msg *m)
{
int chan, n;
Client *c;
switch(m->type){
case SSH_MSG_DISCONNECT:
case SSH_CMSG_EXIT_CONFIRMATION:
sysfatal("disconnect");
case SSH_CMSG_STDIN_DATA:
case SSH_CMSG_EOF:
case SSH_CMSG_WINDOW_SIZE:
/* don't care */
free(m);
break;
case SSH_MSG_CHANNEL_DATA:
chan = getlong(m);
n = getlong(m);
if(m->rp+n != m->ep)
sysfatal("got bad channel data");
if(chan<nclient && (c=client[chan])->state==Established){
queuemsg(c, m);
matchmsgs(c);
}else
free(m);
break;
case SSH_MSG_CHANNEL_INPUT_EOF:
chan = getlong(m);
free(m);
if(chan<nclient){
c = client[chan];
chan = c->servernum;
hangupclient(c);
m = allocmsg(conn, SSH_MSG_CHANNEL_OUTPUT_CLOSED, 4);
putlong(m, chan);
sendmsg(m);
}
break;
case SSH_MSG_CHANNEL_OUTPUT_CLOSED:
chan = getlong(m);
if(chan<nclient)
hangupclient(client[chan]);
free(m);
break;
case SSH_MSG_CHANNEL_OPEN_CONFIRMATION:
chan = getlong(m);
c = nil;
if(chan>=nclient || (c=client[chan])->state != Dialing){
if(c)
fprint(2, "cstate %d\n", c->state);
sysfatal("got unexpected open confirmation for %d", chan);
}
c->servernum = getlong(m);
c->state = Established;
dialedclient(c);
free(m);
break;
case SSH_MSG_CHANNEL_OPEN_FAILURE:
chan = getlong(m);
c = nil;
if(chan>=nclient || (c=client[chan])->state != Dialing)
sysfatal("got unexpected open failure");
if(m->rp+4 <= m->ep)
c->servernum = getlong(m);
c->state = Closed;
dialedclient(c);
free(m);
break;
}
}
void
fsnetproc(void*)
{
ulong path;
Alt a[4];
Cs *cs;
Fid *fid;
Req *r;
Msg *m;
threadsetname("fsthread");
a[0].op = CHANRCV;
a[0].c = fsclunkchan;
a[0].v = &fid;
a[1].op = CHANRCV;
a[1].c = fsreqchan;
a[1].v = &r;
a[2].op = CHANRCV;
a[2].c = sshmsgchan;
a[2].v = &m;
a[3].op = CHANEND;
for(;;){
switch(alt(a)){
case 0:
path = fid->qid.path;
switch(TYPE(path)){
case Qcs:
cs = fid->aux;
if(cs){
free(cs->resp);
free(cs);
}
break;
}
if(fid->omode != -1 && TYPE(path) >= Qn)
closeclient(client[NUM(path)]);
sendp(fsclunkwaitchan, nil);
break;
case 1:
switch(r->ifcall.type){
case Tattach:
fsattach(r);
break;
case Topen:
fsopen(r);
break;
case Tread:
fsread(r);
break;
case Twrite:
fswrite(r);
break;
case Tstat:
fsstat(r);
break;
case Tflush:
fsflush(r);
break;
default:
respond(r, "bug in fsthread");
break;
}
sendp(fsreqwaitchan, 0);
break;
case 2:
handlemsg(m);
break;
}
}
}
static void
fssend(Req *r)
{
sendp(fsreqchan, r);
recvp(fsreqwaitchan); /* avoids need to deal with spurious flushes */
}
static void
fsdestroyfid(Fid *fid)
{
sendp(fsclunkchan, fid);
recvp(fsclunkwaitchan);
}
void
takedown(Srv*)
{
threadexitsall("done");
}
Srv fs =
{
.attach= fssend,
.destroyfid= fsdestroyfid,
.walk1= fswalk1,
.open= fssend,
.read= fssend,
.write= fssend,
.stat= fssend,
.flush= fssend,
.end= takedown,
};
void
threadmain(int argc, char **argv)
{
int i, fd;
char *host, *user, *p, *service;
char *f[16];
Msg *m;
static Conn c;
fmtinstall('B', mpfmt);
fmtinstall('H', encodefmt);
mtpt = "/net";
service = nil;
user = nil;
ARGBEGIN{
case 'B': /* undocumented, debugging */
doabort = 1;
break;
case 'D': /* undocumented, debugging */
debuglevel = strtol(EARGF(usage()), nil, 0);
break;
case '9': /* undocumented, debugging */
chatty9p++;
break;
case 'A':
authlist = EARGF(usage());
break;
case 'c':
cipherlist = EARGF(usage());
break;
case 'm':
mtpt = EARGF(usage());
break;
case 's':
service = EARGF(usage());
break;
default:
usage();
}ARGEND
if(argc != 1)
usage();
host = argv[0];
if((p = strchr(host, '@')) != nil){
*p++ = '\0';
user = host;
host = p;
}
if(user == nil)
user = getenv("user");
if(user == nil)
sysfatal("cannot find user name");
privatefactotum();
if((fd = dial(netmkaddr(host, "tcp", "ssh"), nil, nil, nil)) < 0)
sysfatal("dialing %s: %r", host);
c.interactive = isatty(0);
c.fd[0] = c.fd[1] = fd;
c.user = user;
c.host = host;
setaliases(&c, host);
c.nokcipher = getfields(cipherlist, f, nelem(f), 1, ", ");
c.okcipher = emalloc(sizeof(Cipher*)*c.nokcipher);
for(i=0; i<c.nokcipher; i++)
c.okcipher[i] = findcipher(f[i], allcipher, nelem(allcipher));
c.nokauth = getfields(authlist, f, nelem(f), 1, ", ");
c.okauth = emalloc(sizeof(Auth*)*c.nokauth);
for(i=0; i<c.nokauth; i++)
c.okauth[i] = findauth(f[i], allauth, nelem(allauth));
sshclienthandshake(&c);
requestpty(&c); /* turns on TCP_NODELAY on other side */
m = allocmsg(&c, SSH_CMSG_EXEC_SHELL, 0);
sendmsg(m);
time0 = time(0);
sshmsgchan = chancreate(sizeof(Msg*), 16);
fsreqchan = chancreate(sizeof(Req*), 0);
fsreqwaitchan = chancreate(sizeof(void*), 0);
fsclunkchan = chancreate(sizeof(Fid*), 0);
fsclunkwaitchan = chancreate(sizeof(void*), 0);
conn = &c;
procrfork(sshreadproc, &c, 8192, RFNAMEG|RFNOTEG);
procrfork(fsnetproc, nil, 8192, RFNAMEG|RFNOTEG);
threadpostmountsrv(&fs, service, mtpt, MREPL);
exits(0);
}