ref: 8fab9847269b8f7930642b0ef42bce24a2eabbe9
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; extern char* base; // fs base for devroot 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); static int srvp9auth(int, char*); char *authserver; typedef struct AuthMethod AuthMethod; struct AuthMethod { char *name; /* name of method */ int (*cf)(int); /* client side authentication */ int (*sf)(int, char*); /* server side authentication */ } authmethod[] = { { "p9", p9auth, srvp9auth,}, { 0 } }; AuthMethod *am = authmethod; /* default is p9 */ char *p9authproto = "p9any"; int setam(char*); void exits(char *s) { print("\ngoodbye\n"); for(;;) osyield(); } void usage(void) { fprint(2, "usage: drawterm [-a authserver] [-c cpuserver] [-s secstore] [-u user]\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] { \n" " service=cpu exec rc -li \n" "} \n"; AuthInfo *ai; TLSconn *conn; char *na; int fd; na = netmkaddr(host, "tcp", "17019"); if((fd = dial(na, 0, 0, 0)) < 0) return; 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"); if(authserver == nil) authserver = "auth"; system = getenv("cpu"); if(system == nil) system = "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 'C': cflag++; cmd[0] = '!'; cmd[1] = '\0'; while((p = ARGF()) != nil) { strcat(cmd, " "); strcat(cmd, p); } break; case 'k': keyspec = EARGF(usage()); break; case 'r': base = EARGF(usage()); break; case 's': secstoreserver = EARGF(usage()); break; case 'u': user = EARGF(usage()); break; default: usage(); }ARGEND; if(argc != 0) usage(); if(user == nil) user = readcons("user", nil, 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 bug[256]; 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 */ if(ealgs != nil) snprint(msg, sizeof(msg), "%s %s", am->name, ealgs); else snprint(msg, sizeof(msg), "%s", am->name); writestr(*fd, msg, negstr, 0); n = readstr(*fd, err, sizeof err); if(n < 0) return negstr; if(*err){ werrstr(err); return negstr; } /* authenticate */ *fd = (*am->cf)(*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"); 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); if(pass == nil) again: pass = getkey(u, tr.authdom); if(pass == nil) fatal(1, "no password"); passtokey(&authkey, pass); memset(pass, 0, strlen(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 = strdup(t.suid); ai->cuid = strdup(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)); return ai; } static int srvp9auth(int fd, char *user) { return -1; } /* * set authentication mechanism */ int setam(char *name) { for(am = authmethod; am->name != nil; am++) if(strcmp(am->name, name) == 0) return 0; am = authmethod; return -1; }