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- #include "ssh.h"
- char *cipherlist = "blowfish rc4 3des";
- char *authlist = "tis";
- void fromnet(Conn*);
- void startcmd(Conn*, char*, int*, int*);
- int maxmsg = 256*1024;
- Cipher *allcipher[] = {
- &cipherrc4,
- &cipherblowfish,
- &cipher3des,
- &cipherdes,
- &ciphernone,
- &ciphertwiddle,
- };
- Authsrv *allauthsrv[] = {
- &authsrvpassword,
- &authsrvtis,
- };
- 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;
- }
- Authsrv*
- findauthsrv(char *name, Authsrv **list, int nlist)
- {
- int i;
- for(i=0; i<nlist; i++)
- if(strcmp(name, list[i]->name) == 0)
- return list[i];
- error("unknown authsrv %s", name);
- return nil;
- }
- void
- usage(void)
- {
- fprint(2, "usage: sshserve [-A authlist] [-c cipherlist] client-ip-address\n");
- usage();
- }
- void
- main(int argc, char **argv)
- {
- char *f[16];
- int i;
- Conn c;
- fmtinstall('B', mpfmt);
- fmtinstall('H', encodefmt);
- atexit(atexitkiller);
- atexitkill(getpid());
- memset(&c, 0, sizeof c);
- ARGBEGIN{
- case 'D':
- debuglevel = atoi(EARGF(usage()));
- break;
- case 'A':
- authlist = EARGF(usage());
- break;
- case 'c':
- cipherlist = EARGF(usage());
- break;
- default:
- usage();
- }ARGEND
- if(argc != 1)
- usage();
- c.host = argv[0];
- sshlog("connect from %s", c.host);
- c.serverpriv = rsagen(768, 6, 0);
- if(c.serverpriv == nil)
- sysfatal("rsagen failed: %r");
- c.serverkey = &c.serverpriv->pub;
- 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.nokauthsrv = getfields(authlist, f, nelem(f), 1, ", ");
- c.okauthsrv = emalloc(sizeof(Authsrv*)*c.nokauthsrv);
- for(i=0; i<c.nokauthsrv; i++)
- c.okauthsrv[i] = findauthsrv(f[i], allauthsrv, nelem(allauthsrv));
- sshserverhandshake(&c);
- fromnet(&c);
- }
- void
- fromnet(Conn *c)
- {
- int infd, kidpid, n;
- char *cmd;
- Msg *m;
- infd = kidpid = -1;
- for(;;){
- m = recvmsg(c, -1);
- if(m == nil)
- exits(nil);
- switch(m->type){
- default:
- //badmsg(m, 0);
- sendmsg(allocmsg(c, SSH_SMSG_FAILURE, 0));
- break;
- case SSH_MSG_DISCONNECT:
- sysfatal("client disconnected");
- case SSH_CMSG_REQUEST_PTY:
- sendmsg(allocmsg(c, SSH_SMSG_SUCCESS, 0));
- break;
- case SSH_CMSG_X11_REQUEST_FORWARDING:
- sendmsg(allocmsg(c, SSH_SMSG_FAILURE, 0));
- break;
- case SSH_CMSG_MAX_PACKET_SIZE:
- maxmsg = getlong(m);
- sendmsg(allocmsg(c, SSH_SMSG_SUCCESS, 0));
- break;
- case SSH_CMSG_REQUEST_COMPRESSION:
- sendmsg(allocmsg(c, SSH_SMSG_FAILURE, 0));
- break;
- case SSH_CMSG_EXEC_SHELL:
- startcmd(c, nil, &kidpid, &infd);
- goto InteractiveMode;
- case SSH_CMSG_EXEC_CMD:
- cmd = getstring(m);
- startcmd(c, cmd, &kidpid, &infd);
- goto InteractiveMode;
- }
- free(m);
- }
- InteractiveMode:
- for(;;){
- free(m);
- m = recvmsg(c, -1);
- if(m == nil)
- exits(nil);
- switch(m->type){
- default:
- badmsg(m, 0);
- case SSH_MSG_DISCONNECT:
- postnote(PNGROUP, kidpid, "hangup");
- sysfatal("client disconnected");
- case SSH_CMSG_STDIN_DATA:
- if(infd != 0){
- n = getlong(m);
- write(infd, getbytes(m, n), n);
- }
- break;
- case SSH_CMSG_EOF:
- close(infd);
- infd = -1;
- break;
- case SSH_CMSG_EXIT_CONFIRMATION:
- /* sent by some clients as dying breath */
- exits(nil);
-
- case SSH_CMSG_WINDOW_SIZE:
- /* we don't care */
- break;
- }
- }
- }
- void
- copyout(Conn *c, int fd, int mtype)
- {
- char buf[8192];
- int n, max, pid;
- Msg *m;
- max = sizeof buf;
- if(max > maxmsg - 32) /* 32 is an overestimate of packet overhead */
- max = maxmsg - 32;
- if(max <= 0)
- sysfatal("maximum message size too small");
-
- switch(pid = rfork(RFPROC|RFMEM|RFNOWAIT)){
- case -1:
- sysfatal("fork: %r");
- case 0:
- break;
- default:
- atexitkill(pid);
- return;
- }
- while((n = read(fd, buf, max)) > 0){
- m = allocmsg(c, mtype, 4+n);
- putlong(m, n);
- putbytes(m, buf, n);
- sendmsg(m);
- }
- exits(nil);
- }
- void
- startcmd(Conn *c, char *cmd, int *kidpid, int *kidin)
- {
- int i, pid, kpid;
- int pfd[3][2];
- char *dir;
- char *sysname, *tz;
- Msg *m;
- Waitmsg *w;
- for(i=0; i<3; i++)
- if(pipe(pfd[i]) < 0)
- sysfatal("pipe: %r");
- sysname = getenv("sysname");
- tz = getenv("timezone");
- switch(pid = rfork(RFPROC|RFMEM|RFNOWAIT)){
- case -1:
- sysfatal("fork: %r");
- case 0:
- switch(kpid = rfork(RFPROC|RFNOTEG|RFENVG|RFFDG)){
- case -1:
- sysfatal("fork: %r");
- case 0:
- for(i=0; i<3; i++){
- if(dup(pfd[i][1], i) < 0)
- sysfatal("dup: %r");
- close(pfd[i][0]);
- close(pfd[i][1]);
- }
- putenv("user", c->user);
- if(sysname)
- putenv("sysname", sysname);
- if(tz)
- putenv("tz", tz);
-
- dir = smprint("/usr/%s", c->user);
- if(dir == nil || chdir(dir) < 0)
- chdir("/");
- if(cmd){
- putenv("service", "rx");
- execl("/bin/rc", "rc", "-lc", cmd, nil);
- sysfatal("cannot exec /bin/rc: %r");
- }else{
- putenv("service", "con");
- execl("/bin/ip/telnetd", "telnetd", "-tn", nil);
- sysfatal("cannot exec /bin/ip/telnetd: %r");
- }
- default:
- *kidpid = kpid;
- rendezvous(kidpid, 0);
- for(;;){
- if((w = wait()) == nil)
- sysfatal("wait: %r");
- if(w->pid == kpid)
- break;
- free(w);
- }
- if(w->msg[0]){
- m = allocmsg(c, SSH_MSG_DISCONNECT, 4+strlen(w->msg));
- putstring(m, w->msg);
- sendmsg(m);
- }else{
- m = allocmsg(c, SSH_SMSG_EXITSTATUS, 4);
- putlong(m, 0);
- sendmsg(m);
- }
- for(i=0; i<3; i++)
- close(pfd[i][0]);
- free(w);
- exits(nil);
- break;
- }
- default:
- atexitkill(pid);
- rendezvous(kidpid, 0);
- break;
- }
- for(i=0; i<3; i++)
- close(pfd[i][1]);
- copyout(c, pfd[1][0], SSH_SMSG_STDOUT_DATA);
- copyout(c, pfd[2][0], SSH_SMSG_STDERR_DATA);
- *kidin = pfd[0][0];
- }
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