diff options
Diffstat (limited to 'src/cmd/auth/factotum/secstore.c')
| -rw-r--r-- | src/cmd/auth/factotum/secstore.c | 644 |
1 files changed, 644 insertions, 0 deletions
diff --git a/src/cmd/auth/factotum/secstore.c b/src/cmd/auth/factotum/secstore.c new file mode 100644 index 00000000..d82d7862 --- /dev/null +++ b/src/cmd/auth/factotum/secstore.c @@ -0,0 +1,644 @@ +/* + * Various files from /sys/src/cmd/auth/secstore, just enough + * to download a file at boot time. + */ + +#include "std.h" +#include "dat.h" +#include <ip.h> + +enum{ CHK = 16}; +enum{ MAXFILESIZE = 10*1024*1024 }; + +enum{// PW status bits + Enabled = (1<<0), + STA = (1<<1), // extra SecurID step +}; + +static char testmess[] = "__secstore\tPAK\nC=%s\nm=0\n"; +char *secstore; + +int +secdial(void) +{ + char *p; + + p = secstore; + if(p == nil) /* else use the authserver */ + p = getenv("secstore"); + if(p == nil) + p = getenv("auth"); + if(p == nil) + p = "secstore"; + + return dial(netmkaddr(p, "net", "secstore"), 0, 0, 0); +} + + +int +havesecstore(void) +{ + int m, n, fd; + uchar buf[500]; + + n = snprint((char*)buf, sizeof buf, testmess, owner); + hnputs(buf, 0x8000+n-2); + + fd = secdial(); + if(fd < 0) + return 0; + if(write(fd, buf, n) != n || readn(fd, buf, 2) != 2){ + close(fd); + return 0; + } + n = ((buf[0]&0x7f)<<8) + buf[1]; + if(n+1 > sizeof buf){ + werrstr("implausibly large count %d", n); + close(fd); + return 0; + } + m = readn(fd, buf, n); + close(fd); + if(m != n){ + if(m >= 0) + werrstr("short read from secstore"); + return 0; + } + buf[n] = 0; + if(strcmp((char*)buf, "!account expired") == 0){ + werrstr("account expired"); + return 0; + } + return strcmp((char*)buf, "!account exists") == 0; +} + +// delimited, authenticated, encrypted connection +enum{ Maxmsg=4096 }; // messages > Maxmsg bytes are truncated +typedef struct SConn SConn; + +extern SConn* newSConn(int); // arg is open file descriptor +struct SConn{ + void *chan; + int secretlen; + int (*secret)(SConn*, uchar*, int);// + int (*read)(SConn*, uchar*, int); // <0 if error; errmess in buffer + int (*write)(SConn*, uchar*, int); + void (*free)(SConn*); // also closes file descriptor +}; +// secret(s,b,dir) sets secret for digest, encrypt, using the secretlen +// bytes in b to form keys for the two directions; +// set dir=0 in client, dir=1 in server + +// error convention: write !message in-band +#define readstr secstore_readstr +static void writerr(SConn*, char*); +static int readstr(SConn*, char*); // call with buf of size Maxmsg+1 + // returns -1 upon error, with error message in buf + +typedef struct ConnState { + uchar secret[SHA1dlen]; + ulong seqno; + RC4state rc4; +} ConnState; + +typedef struct SS{ + int fd; // file descriptor for read/write of encrypted data + int alg; // if nonzero, "alg sha rc4_128" + ConnState in, out; +} SS; + +static int +SC_secret(SConn *conn, uchar *sigma, int direction) +{ + SS *ss = (SS*)(conn->chan); + int nsigma = conn->secretlen; + + if(direction != 0){ + hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->out.secret, nil); + hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->in.secret, nil); + }else{ + hmac_sha1(sigma, nsigma, (uchar*)"two", 3, ss->out.secret, nil); + hmac_sha1(sigma, nsigma, (uchar*)"one", 3, ss->in.secret, nil); + } + setupRC4state(&ss->in.rc4, ss->in.secret, 16); // restrict to 128 bits + setupRC4state(&ss->out.rc4, ss->out.secret, 16); + ss->alg = 1; + return 0; +} + +static void +hash(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]) +{ + DigestState sha; + uchar seq[4]; + + seq[0] = seqno>>24; + seq[1] = seqno>>16; + seq[2] = seqno>>8; + seq[3] = seqno; + memset(&sha, 0, sizeof sha); + sha1(secret, SHA1dlen, nil, &sha); + sha1(data, len, nil, &sha); + sha1(seq, 4, d, &sha); +} + +static int +verify(uchar secret[SHA1dlen], uchar *data, int len, int seqno, uchar d[SHA1dlen]) +{ + DigestState sha; + uchar seq[4]; + uchar digest[SHA1dlen]; + + seq[0] = seqno>>24; + seq[1] = seqno>>16; + seq[2] = seqno>>8; + seq[3] = seqno; + memset(&sha, 0, sizeof sha); + sha1(secret, SHA1dlen, nil, &sha); + sha1(data, len, nil, &sha); + sha1(seq, 4, digest, &sha); + return memcmp(d, digest, SHA1dlen); +} + +static int +SC_read(SConn *conn, uchar *buf, int n) +{ + SS *ss = (SS*)(conn->chan); + uchar count[2], digest[SHA1dlen]; + int len, nr; + + if(read(ss->fd, count, 2) != 2 || count[0]&0x80 == 0){ + werrstr("!SC_read invalid count"); + return -1; + } + len = (count[0]&0x7f)<<8 | count[1]; // SSL-style count; no pad + if(ss->alg){ + len -= SHA1dlen; + if(len <= 0 || readn(ss->fd, digest, SHA1dlen) != SHA1dlen){ + werrstr("!SC_read missing sha1"); + return -1; + } + if(len > n || readn(ss->fd, buf, len) != len){ + werrstr("!SC_read missing data"); + return -1; + } + rc4(&ss->in.rc4, digest, SHA1dlen); + rc4(&ss->in.rc4, buf, len); + if(verify(ss->in.secret, buf, len, ss->in.seqno, digest) != 0){ + werrstr("!SC_read integrity check failed"); + return -1; + } + }else{ + if(len <= 0 || len > n){ + werrstr("!SC_read implausible record length"); + return -1; + } + if( (nr = readn(ss->fd, buf, len)) != len){ + werrstr("!SC_read expected %d bytes, but got %d", len, nr); + return -1; + } + } + ss->in.seqno++; + return len; +} + +static int +SC_write(SConn *conn, uchar *buf, int n) +{ + SS *ss = (SS*)(conn->chan); + uchar count[2], digest[SHA1dlen], enc[Maxmsg+1]; + int len; + + if(n <= 0 || n > Maxmsg+1){ + werrstr("!SC_write invalid n %d", n); + return -1; + } + len = n; + if(ss->alg) + len += SHA1dlen; + count[0] = 0x80 | len>>8; + count[1] = len; + if(write(ss->fd, count, 2) != 2){ + werrstr("!SC_write invalid count"); + return -1; + } + if(ss->alg){ + hash(ss->out.secret, buf, n, ss->out.seqno, digest); + rc4(&ss->out.rc4, digest, SHA1dlen); + memcpy(enc, buf, n); + rc4(&ss->out.rc4, enc, n); + if(write(ss->fd, digest, SHA1dlen) != SHA1dlen || + write(ss->fd, enc, n) != n){ + werrstr("!SC_write error on send"); + return -1; + } + }else{ + if(write(ss->fd, buf, n) != n){ + werrstr("!SC_write error on send"); + return -1; + } + } + ss->out.seqno++; + return n; +} + +static void +SC_free(SConn *conn) +{ + SS *ss = (SS*)(conn->chan); + + close(ss->fd); + free(ss); + free(conn); +} + +SConn* +newSConn(int fd) +{ + SS *ss; + SConn *conn; + + if(fd < 0) + return nil; + ss = (SS*)emalloc(sizeof(*ss)); + conn = (SConn*)emalloc(sizeof(*conn)); + ss->fd = fd; + ss->alg = 0; + conn->chan = (void*)ss; + conn->secretlen = SHA1dlen; + conn->free = SC_free; + conn->secret = SC_secret; + conn->read = SC_read; + conn->write = SC_write; + return conn; +} + +static void +writerr(SConn *conn, char *s) +{ + char buf[Maxmsg]; + + snprint(buf, Maxmsg, "!%s", s); + conn->write(conn, (uchar*)buf, strlen(buf)); +} + +static int +readstr(SConn *conn, char *s) +{ + int n; + + n = conn->read(conn, (uchar*)s, Maxmsg); + if(n >= 0){ + s[n] = 0; + if(s[0] == '!'){ + memmove(s, s+1, n); + n = -1; + } + }else{ + strcpy(s, "read error"); + } + return n; +} + +static int +getfile(SConn *conn, uchar *key, int nkey) +{ + char *buf; + int nbuf, n, nr, len; + char s[Maxmsg+1], *gf, *p, *q; + uchar skey[SHA1dlen], ib[Maxmsg+CHK], *ibr, *ibw; + AESstate aes; + DigestState *sha; + + gf = "factotum"; + memset(&aes, 0, sizeof aes); + + snprint(s, Maxmsg, "GET %s\n", gf); + conn->write(conn, (uchar*)s, strlen(s)); + + /* get file size */ + s[0] = '\0'; + if(readstr(conn, s) < 0){ + werrstr("secstore: %r"); + return -1; + } + if((len = atoi(s)) < 0){ + werrstr("secstore: remote file %s does not exist", gf); + return -1; + }else if(len > MAXFILESIZE){//assert + werrstr("secstore: implausible file size %d for %s", len, gf); + return -1; + } + + ibr = ibw = ib; + buf = nil; + nbuf = 0; + for(nr=0; nr < len;){ + if((n = conn->read(conn, ibw, Maxmsg)) <= 0){ + werrstr("secstore: empty file chunk n=%d nr=%d len=%d: %r", n, nr, len); + return -1; + } + nr += n; + ibw += n; + if(!aes.setup){ /* first time, read 16 byte IV */ + if(n < 16){ + werrstr("secstore: no IV in file"); + return -1; + } + sha = sha1((uchar*)"aescbc file", 11, nil, nil); + sha1(key, nkey, skey, sha); + setupAESstate(&aes, skey, AESbsize, ibr); + memset(skey, 0, sizeof skey); + ibr += AESbsize; + n -= AESbsize; + } + aesCBCdecrypt(ibw-n, n, &aes); + n = ibw-ibr-CHK; + if(n > 0){ + buf = erealloc(buf, nbuf+n+1); + memmove(buf+nbuf, ibr, n); + nbuf += n; + ibr += n; + } + memmove(ib, ibr, ibw-ibr); + ibw = ib + (ibw-ibr); + ibr = ib; + } + n = ibw-ibr; + if((n != CHK) || (memcmp(ib, "XXXXXXXXXXXXXXXX", CHK) != 0)){ + werrstr("secstore: decrypted file failed to authenticate!"); + free(buf); + return -1; + } + if(nbuf == 0){ + werrstr("secstore got empty file"); + return -1; + } + buf[nbuf] = '\0'; + p = buf; + n = 0; + while(p){ + if(q = strchr(p, '\n')) + *q++ = '\0'; + n++; + if(ctlwrite(p) < 0) + fprint(2, "secstore(%s) line %d: %r\n", gf, n); + p = q; + } + free(buf); + return 0; +} + +static char VERSION[] = "secstore"; + +typedef struct PAKparams{ + mpint *q, *p, *r, *g; +} PAKparams; + +static PAKparams *pak; + +// This group was generated by the seed EB7B6E35F7CD37B511D96C67D6688CC4DD440E1E. +static void +initPAKparams(void) +{ + if(pak) + return; + pak = (PAKparams*)emalloc(sizeof(*pak)); + pak->q = strtomp("E0F0EF284E10796C5A2A511E94748BA03C795C13", nil, 16, nil); + pak->p = strtomp("C41CFBE4D4846F67A3DF7DE9921A49D3B42DC33728427AB159CEC8CBBD" + "B12B5F0C244F1A734AEB9840804EA3C25036AD1B61AFF3ABBC247CD4B384224567A86" + "3A6F020E7EE9795554BCD08ABAD7321AF27E1E92E3DB1C6E7E94FAAE590AE9C48F96D9" + "3D178E809401ABE8A534A1EC44359733475A36A70C7B425125062B1142D", nil, 16, nil); + pak->r = strtomp("DF310F4E54A5FEC5D86D3E14863921E834113E060F90052AD332B3241CEF" + "2497EFA0303D6344F7C819691A0F9C4A773815AF8EAECFB7EC1D98F039F17A32A7E887" + "D97251A927D093F44A55577F4D70444AEBD06B9B45695EC23962B175F266895C67D21" + "C4656848614D888A4", nil, 16, nil); + pak->g = strtomp("2F1C308DC46B9A44B52DF7DACCE1208CCEF72F69C743ADD4D2327173444" + "ED6E65E074694246E07F9FD4AE26E0FDDD9F54F813C40CB9BCD4338EA6F242AB94CD41" + "0E676C290368A16B1A3594877437E516C53A6EEE5493A038A017E955E218E7819734E3E" + "2A6E0BAE08B14258F8C03CC1B30E0DDADFCF7CEDF0727684D3D255F1", nil, 16, nil); +} + +// H = (sha(ver,C,sha(passphrase)))^r mod p, +// a hash function expensive to attack by brute force. +static void +longhash(char *ver, char *C, uchar *passwd, mpint *H) +{ + uchar *Cp; + int i, n, nver, nC; + uchar buf[140], key[1]; + + nver = strlen(ver); + nC = strlen(C); + n = nver + nC + SHA1dlen; + Cp = (uchar*)emalloc(n); + memmove(Cp, ver, nver); + memmove(Cp+nver, C, nC); + memmove(Cp+nver+nC, passwd, SHA1dlen); + for(i = 0; i < 7; i++){ + key[0] = 'A'+i; + hmac_sha1(Cp, n, key, sizeof key, buf+i*SHA1dlen, nil); + } + memset(Cp, 0, n); + free(Cp); + betomp(buf, sizeof buf, H); + mpmod(H, pak->p, H); + mpexp(H, pak->r, pak->p, H); +} + +// Hi = H^-1 mod p +static char * +PAK_Hi(char *C, char *passphrase, mpint *H, mpint *Hi) +{ + uchar passhash[SHA1dlen]; + + sha1((uchar *)passphrase, strlen(passphrase), passhash, nil); + initPAKparams(); + longhash(VERSION, C, passhash, H); + mpinvert(H, pak->p, Hi); + return mptoa(Hi, 64, nil, 0); +} + +// another, faster, hash function for each party to +// confirm that the other has the right secrets. +static void +shorthash(char *mess, char *C, char *S, char *m, char *mu, char *sigma, char *Hi, uchar *digest) +{ + SHA1state *state; + + state = sha1((uchar*)mess, strlen(mess), 0, 0); + state = sha1((uchar*)C, strlen(C), 0, state); + state = sha1((uchar*)S, strlen(S), 0, state); + state = sha1((uchar*)m, strlen(m), 0, state); + state = sha1((uchar*)mu, strlen(mu), 0, state); + state = sha1((uchar*)sigma, strlen(sigma), 0, state); + state = sha1((uchar*)Hi, strlen(Hi), 0, state); + state = sha1((uchar*)mess, strlen(mess), 0, state); + state = sha1((uchar*)C, strlen(C), 0, state); + state = sha1((uchar*)S, strlen(S), 0, state); + state = sha1((uchar*)m, strlen(m), 0, state); + state = sha1((uchar*)mu, strlen(mu), 0, state); + state = sha1((uchar*)sigma, strlen(sigma), 0, state); + sha1((uchar*)Hi, strlen(Hi), digest, state); +} + +// On input, conn provides an open channel to the server; +// C is the name this client calls itself; +// pass is the user's passphrase +// On output, session secret has been set in conn +// (unless return code is negative, which means failure). +// If pS is not nil, it is set to the (alloc'd) name the server calls itself. +static int +PAKclient(SConn *conn, char *C, char *pass, char **pS) +{ + char *mess, *mess2, *eol, *S, *hexmu, *ks, *hexm, *hexsigma = nil, *hexHi; + char kc[2*SHA1dlen+1]; + uchar digest[SHA1dlen]; + int rc = -1, n; + mpint *x, *m = mpnew(0), *mu = mpnew(0), *sigma = mpnew(0); + mpint *H = mpnew(0), *Hi = mpnew(0); + + hexHi = PAK_Hi(C, pass, H, Hi); + + // random 1<=x<=q-1; send C, m=g**x H + x = mprand(164, genrandom, nil); + mpmod(x, pak->q, x); + if(mpcmp(x, mpzero) == 0) + mpassign(mpone, x); + mpexp(pak->g, x, pak->p, m); + mpmul(m, H, m); + mpmod(m, pak->p, m); + hexm = mptoa(m, 64, nil, 0); + mess = (char*)emalloc(2*Maxmsg+2); + mess2 = mess+Maxmsg+1; + snprint(mess, Maxmsg, "%s\tPAK\nC=%s\nm=%s\n", VERSION, C, hexm); + conn->write(conn, (uchar*)mess, strlen(mess)); + + // recv g**y, S, check hash1(g**xy) + if(readstr(conn, mess) < 0){ + fprint(2, "error: %s\n", mess); + writerr(conn, "couldn't read g**y"); + goto done; + } + eol = strchr(mess, '\n'); + if(strncmp("mu=", mess, 3) != 0 || !eol || strncmp("\nk=", eol, 3) != 0){ + writerr(conn, "verifier syntax error"); + goto done; + } + hexmu = mess+3; + *eol = 0; + ks = eol+3; + eol = strchr(ks, '\n'); + if(!eol || strncmp("\nS=", eol, 3) != 0){ + writerr(conn, "verifier syntax error for secstore 1.0"); + goto done; + } + *eol = 0; + S = eol+3; + eol = strchr(S, '\n'); + if(!eol){ + writerr(conn, "verifier syntax error for secstore 1.0"); + goto done; + } + *eol = 0; + if(pS) + *pS = estrdup(S); + strtomp(hexmu, nil, 64, mu); + mpexp(mu, x, pak->p, sigma); + hexsigma = mptoa(sigma, 64, nil, 0); + shorthash("server", C, S, hexm, hexmu, hexsigma, hexHi, digest); + enc64(kc, sizeof kc, digest, SHA1dlen); + if(strcmp(ks, kc) != 0){ + writerr(conn, "verifier didn't match"); + goto done; + } + + // send hash2(g**xy) + shorthash("client", C, S, hexm, hexmu, hexsigma, hexHi, digest); + enc64(kc, sizeof kc, digest, SHA1dlen); + snprint(mess2, Maxmsg, "k'=%s\n", kc); + conn->write(conn, (uchar*)mess2, strlen(mess2)); + + // set session key + shorthash("session", C, S, hexm, hexmu, hexsigma, hexHi, digest); + memset(hexsigma, 0, strlen(hexsigma)); + n = conn->secret(conn, digest, 0); + memset(digest, 0, SHA1dlen); + if(n < 0){//assert + writerr(conn, "can't set secret"); + goto done; + } + + rc = 0; +done: + mpfree(x); + mpfree(sigma); + mpfree(mu); + mpfree(m); + mpfree(Hi); + mpfree(H); + free(hexsigma); + free(hexHi); + free(hexm); + free(mess); + return rc; +} + +int +secstorefetch(void) +{ + int rv = -1, fd; + char s[Maxmsg+1]; + SConn *conn; + char *pass, *sta; + + sta = nil; + conn = nil; + pass = readcons("secstore password", nil, 1); + if(pass==nil || strlen(pass)==0){ + werrstr("cancel"); + goto Out; + } + if((fd = secdial()) < 0) + goto Out; + if((conn = newSConn(fd)) == nil) + goto Out; + if(PAKclient(conn, owner, pass, nil) < 0){ + werrstr("password mistyped?"); + goto Out; + } + if(readstr(conn, s) < 0) + goto Out; + if(strcmp(s, "STA") == 0){ + sta = readcons("STA PIN+SecureID", nil, 1); + if(sta==nil || strlen(sta)==0){ + werrstr("cancel"); + goto Out; + } + if(strlen(sta) >= sizeof s - 3){ + werrstr("STA response too long"); + goto Out; + } + strcpy(s+3, sta); + conn->write(conn, (uchar*)s, strlen(s)); + readstr(conn, s); + } + if(strcmp(s, "OK") !=0){ + werrstr("%s", s); + goto Out; + } + if(getfile(conn, (uchar*)pass, strlen(pass)) < 0) + goto Out; + conn->write(conn, (uchar*)"BYE", 3); + rv = 0; + +Out: + if(conn) + conn->free(conn); + if(pass) + free(pass); + if(sta) + free(sta); + return rv; +} + |