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secstore from ehg

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This commit is contained in:
rsc 2004-12-27 19:36:51 +00:00
parent 73bfbacb24
commit a812ae4b43
10 changed files with 1633 additions and 0 deletions
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213
src/cmd/secstore/SConn.c Normal file
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#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#include "SConn.h"
extern int verbose;
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){
snprint((char*)buf,n,"!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){
snprint((char*)buf,n,"!SC_read missing sha1");
return -1;
}
if(len > n || readn(ss->fd, buf, len) != len){
snprint((char*)buf,n,"!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){
snprint((char*)buf,n,"!SC_read integrity check failed");
return -1;
}
}else{
if(len <= 0 || len > n){
snprint((char*)buf,n,"!SC_read implausible record length");
return -1;
}
if( (nr = readn(ss->fd, buf, len)) != len){
snprint((char*)buf,n,"!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;
}
void
writerr(SConn *conn, char *s)
{
char buf[Maxmsg];
snprint(buf, Maxmsg, "!%s", s);
conn->write(conn, (uchar*)buf, strlen(buf));
}
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;
}

26
src/cmd/secstore/SConn.h Normal file
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// 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
extern void writerr(SConn*, char*);
extern int readstr(SConn*, char*); // call with buf of size Maxmsg+1
// returns -1 upon error, with error message in buf
extern void *emalloc(ulong); /* dies on failure; clears memory */
extern void *erealloc(void *, ulong);
extern char *estrdup(char *);

156
src/cmd/secstore/aescbc.c Normal file
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/* encrypt file by writing
v2hdr,
16byte initialization vector,
AES-CBC(key, random | file),
HMAC_SHA1(md5(key), AES-CBC(random | file))
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <mp.h>
#include <libsec.h>
extern char* getpassm(char*);
enum{ CHK = 16, BUF = 4096 };
uchar v2hdr[AESbsize+1] = "AES CBC SHA1 2\n";
Biobuf bin;
Biobuf bout;
void
safewrite(uchar *buf, int n)
{
int i = Bwrite(&bout, buf, n);
if(i == n)
return;
fprint(2, "write error\n");
exits("write error");
}
void
saferead(uchar *buf, int n)
{
int i = Bread(&bin, buf, n);
if(i == n)
return;
fprint(2, "read error\n");
exits("read error");
}
int
main(int argc, char **argv)
{
int encrypt = 0; /* 0=decrypt, 1=encrypt */
int n, nkey, pass_stdin = 0;
char *pass;
uchar key[AESmaxkey], key2[SHA1dlen];
uchar buf[BUF+SHA1dlen]; /* assumption: CHK <= SHA1dlen */
AESstate aes;
DigestState *dstate;
ARGBEGIN{
case 'e':
encrypt = 1;
break;
case 'i':
pass_stdin = 1;
break;
}ARGEND;
if(argc!=0){
fprint(2,"usage: %s -d < cipher.aes > clear.txt\n", argv0);
fprint(2," or: %s -e < clear.txt > cipher.aes\n", argv0);
exits("usage");
}
Binit(&bin, 0, OREAD);
Binit(&bout, 1, OWRITE);
if(pass_stdin){
n = readn(3, buf, (sizeof buf)-1);
if(n < 1)
exits("usage: echo password |[3=1] auth/aescbc -i ...");
buf[n] = 0;
while(buf[n-1] == '\n')
buf[--n] = 0;
}else{
pass = getpassm("aescbc key:");
n = strlen(pass);
if(n >= BUF)
exits("key too long");
strcpy((char*)buf, pass);
memset(pass, 0, n);
free(pass);
}
if(n <= 0){
fprint(2,"no key\n");
exits("key");
}
dstate = sha1((uchar*)"aescbc file", 11, nil, nil);
sha1(buf, n, key2, dstate);
memcpy(key, key2, 16);
nkey = 16;
md5(key, nkey, key2, 0); /* so even if HMAC_SHA1 is broken, encryption key is protected */
if(encrypt){
safewrite(v2hdr, AESbsize);
genrandom(buf,2*AESbsize); /* CBC is semantically secure if IV is unpredictable. */
setupAESstate(&aes, key, nkey, buf); /* use first AESbsize bytes as IV */
aesCBCencrypt(buf+AESbsize, AESbsize, &aes); /* use second AESbsize bytes as initial plaintext */
safewrite(buf, 2*AESbsize);
dstate = hmac_sha1(buf+AESbsize, AESbsize, key2, MD5dlen, 0, 0);
while(1){
n = Bread(&bin, buf, BUF);
if(n < 0){
fprint(2,"read error\n");
exits("read error");
}
aesCBCencrypt(buf, n, &aes);
safewrite(buf, n);
dstate = hmac_sha1(buf, n, key2, MD5dlen, 0, dstate);
if(n < BUF)
break; /* EOF */
}
hmac_sha1(0, 0, key2, MD5dlen, buf, dstate);
safewrite(buf, SHA1dlen);
}else{ /* decrypt */
saferead(buf, AESbsize);
if(memcmp(buf, v2hdr, AESbsize) == 0){
saferead(buf, 2*AESbsize); /* read IV and random initial plaintext */
setupAESstate(&aes, key, nkey, buf);
dstate = hmac_sha1(buf+AESbsize, AESbsize, key2, MD5dlen, 0, 0);
aesCBCdecrypt(buf+AESbsize, AESbsize, &aes);
saferead(buf, SHA1dlen);
while((n = Bread(&bin, buf+SHA1dlen, BUF)) > 0){
dstate = hmac_sha1(buf, n, key2, MD5dlen, 0, dstate);
aesCBCdecrypt(buf, n, &aes);
safewrite(buf, n);
memmove(buf, buf+n, SHA1dlen); /* these bytes are not yet decrypted */
}
hmac_sha1(0, 0, key2, MD5dlen, buf+SHA1dlen, dstate);
if(memcmp(buf, buf+SHA1dlen, SHA1dlen) != 0){
fprint(2,"decrypted file failed to authenticate\n");
exits("decrypted file failed to authenticate");
}
}else{ /* compatibility with past mistake */
// if file was encrypted with bad aescbc use this:
// memset(key, 0, AESmaxkey);
// else assume we're decrypting secstore files
setupAESstate(&aes, key, AESbsize, buf);
saferead(buf, CHK);
aesCBCdecrypt(buf, CHK, &aes);
while((n = Bread(&bin, buf+CHK, BUF)) > 0){
aesCBCdecrypt(buf+CHK, n, &aes);
safewrite(buf, n);
memmove(buf, buf+n, CHK);
}
if(memcmp(buf, "XXXXXXXXXXXXXXXX", CHK) != 0){
fprint(2,"decrypted file failed to authenticate\n");
exits("decrypted file failed to authenticate");
}
}
}
exits("");
return 1; /* gcc */
}

87
src/cmd/secstore/dirls.c Normal file
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#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#include "SConn.h"
static long
ls(char *p, Dir **dirbuf)
{
int fd;
long n;
Dir *db;
if((db = dirstat(p)) == nil ||
!(db->qid.type & QTDIR) ||
(fd = open(p, OREAD)) < 0 )
return -1;
free(db);
n = dirreadall(fd, dirbuf);
close(fd);
return n;
}
static uchar*
sha1file(char *pfx, char *nm)
{
int n, fd, len;
char *tmp;
uchar buf[8192];
static uchar digest[SHA1dlen];
DigestState *s;
len = strlen(pfx)+1+strlen(nm)+1;
tmp = emalloc(len);
snprint(tmp, len, "%s/%s", pfx, nm);
if((fd = open(tmp, OREAD)) < 0){
free(tmp);
return nil;
}
free(tmp);
s = nil;
while((n = read(fd, buf, sizeof buf)) > 0)
s = sha1(buf, n, nil, s);
close(fd);
sha1(nil, 0, digest, s);
return digest;
}
static int
compare(Dir *a, Dir *b)
{
return strcmp(a->name, b->name);
}
/* list the (name mtime size sum) of regular, readable files in path */
char *
dirls(char *path)
{
char *list, *date, dig[30], buf[128];
int m, nmwid, lenwid;
long i, n, ndir, len;
Dir *dirbuf;
if(path==nil || (ndir = ls(path, &dirbuf)) < 0)
return nil;
qsort(dirbuf, ndir, sizeof dirbuf[0], (int (*)(void *, void *))compare);
for(nmwid=lenwid=i=0; i<ndir; i++){
if((m = strlen(dirbuf[i].name)) > nmwid)
nmwid = m;
snprint(buf, sizeof(buf), "%ulld", dirbuf[i].length);
if((m = strlen(buf)) > lenwid)
lenwid = m;
}
for(list=nil, len=0, i=0; i<ndir; i++){
date = ctime(dirbuf[i].mtime);
date[28] = 0; // trim newline
n = snprint(buf, sizeof buf, "%*ulld %s", lenwid, dirbuf[i].length, date+4);
n += enc64(dig, sizeof dig, sha1file(path, dirbuf[i].name), SHA1dlen);
n += nmwid+3+strlen(dirbuf[i].name);
list = erealloc(list, len+n+1);
len += snprint(list+len, n+1, "%-*s\t%s %s\n", nmwid, dirbuf[i].name, buf, dig);
}
free(dirbuf);
return list;
}

23
src/cmd/secstore/mkfile Normal file
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<$PLAN9/src/mkhdr
BIN=$PLAN9/bin
#CFLAGS=-Fw
HFILES =\
SConn.h\
secstore.h\
OFILES =\
pak.$O\
password.$O\
SConn.$O\
util.$O\
TARG=aescbc secstore
SHORTLIB=sec mp regexp9 thread bio 9
<$PLAN9/src/mkmany
$O.aescbc: aescbc.$O util.$O $LIB ${SHORTLIB:%=$LIBDIR/lib%.a}
$LD -o $target $prereq $LDFLAGS

344
src/cmd/secstore/pak.c Normal file
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// PAK is an encrypted key exchange protocol designed by Philip MacKenzie et al.
// It is patented and use outside Plan 9 requires you get a license.
// (All other EKE protocols are patented as well, by Lucent or others.)
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#include "SConn.h"
#include "secstore.h"
extern int verbose;
char VERSION[] = "secstore";
static char *feedback[] = {"alpha","bravo","charlie","delta","echo","foxtrot","golf","hotel"};
typedef struct PAKparams{
mpint *q, *p, *r, *g;
} PAKparams;
static PAKparams *pak;
// from seed EB7B6E35F7CD37B511D96C67D6688CC4DD440E1E
static void
initPAKparams(void)
{
if(pak)
return;
pak = (PAKparams*)emalloc(sizeof(*pak));
pak->q = strtomp("E0F0EF284E10796C5A2A511E94748BA03C795C13", nil, 16, nil);
pak->p = strtomp("C41CFBE4D4846F67A3DF7DE9921A49D3B42DC33728427AB159CEC8CBB"
"DB12B5F0C244F1A734AEB9840804EA3C25036AD1B61AFF3ABBC247CD4B384224567A86"
"3A6F020E7EE9795554BCD08ABAD7321AF27E1E92E3DB1C6E7E94FAAE590AE9C48F96D9"
"3D178E809401ABE8A534A1EC44359733475A36A70C7B425125062B1142D",
nil, 16, nil);
pak->r = strtomp("DF310F4E54A5FEC5D86D3E14863921E834113E060F90052AD332B3241"
"CEF2497EFA0303D6344F7C819691A0F9C4A773815AF8EAECFB7EC1D98F039F17A32A7E"
"887D97251A927D093F44A55577F4D70444AEBD06B9B45695EC23962B175F266895C67D"
"21C4656848614D888A4", nil, 16, nil);
pak->g = strtomp("2F1C308DC46B9A44B52DF7DACCE1208CCEF72F69C743ADD4D23271734"
"44ED6E65E074694246E07F9FD4AE26E0FDDD9F54F813C40CB9BCD4338EA6F242AB94CD"
"410E676C290368A16B1A3594877437E516C53A6EEE5493A038A017E955E218E7819734"
"E3E2A6E0BAE08B14258F8C03CC1B30E0DDADFCF7CEDF0727684D3D255F1",
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
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.
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);
if(verbose)
fprint(2,"%s\n", feedback[H->p[0]&0x7]); // provide a clue to catch typos
// random 1<=x<=q-1; send C, m=g**x H
x = mprand(240, 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){
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;
}
// On input,
// mess contains first message;
// name is name this server should call itself.
// On output, session secret has been set in conn;
// if pw!=nil, then *pw points to PW struct for authenticated user.
// returns -1 if error
int
PAKserver(SConn *conn, char *S, char *mess, PW **pwp)
{
int rc = -1, n;
char mess2[Maxmsg+1], *eol;
char *C, ks[41], *kc, *hexm, *hexmu = nil, *hexsigma = nil, *hexHi = nil;
uchar digest[SHA1dlen];
mpint *H = mpnew(0), *Hi = mpnew(0);
mpint *y = nil, *m = mpnew(0), *mu = mpnew(0), *sigma = mpnew(0);
PW *pw = nil;
// secstore version and algorithm
snprint(mess2,Maxmsg,"%s\tPAK\n", VERSION);
n = strlen(mess2);
if(strncmp(mess,mess2,n) != 0){
writerr(conn, "protocol should start with ver alg");
return -1;
}
mess += n;
initPAKparams();
// parse first message into C, m
eol = strchr(mess, '\n');
if(strncmp("C=", mess, 2) != 0 || !eol){
fprint(2,"mess[1]=%s\n", mess);
writerr(conn, "PAK version mismatch");
goto done;
}
C = mess+2;
*eol = 0;
hexm = eol+3;
eol = strchr(hexm, '\n');
if(strncmp("m=", hexm-2, 2) != 0 || !eol){
writerr(conn, "PAK version mismatch");
goto done;
}
*eol = 0;
strtomp(hexm, nil, 64, m);
mpmod(m, pak->p, m);
// lookup client
if((pw = getPW(C,0)) == nil) {
snprint(mess2, sizeof mess2, "%r");
writerr(conn, mess2);
goto done;
}
if(mpcmp(m, mpzero) == 0) {
writerr(conn, "account exists");
freePW(pw);
pw = nil;
goto done;
}
hexHi = mptoa(pw->Hi, 64, nil, 0);
// random y, mu=g**y, sigma=g**xy
y = mprand(240, genrandom, nil);
mpmod(y, pak->q, y);
if(mpcmp(y, mpzero) == 0){
mpassign(mpone, y);
}
mpexp(pak->g, y, pak->p, mu);
mpmul(m, pw->Hi, m);
mpmod(m, pak->p, m);
mpexp(m, y, pak->p, sigma);
// send g**y, hash1(g**xy)
hexmu = mptoa(mu, 64, nil, 0);
hexsigma = mptoa(sigma, 64, nil, 0);
shorthash("server", C, S, hexm, hexmu, hexsigma, hexHi, digest);
enc64(ks, sizeof ks, digest, SHA1dlen);
snprint(mess2, sizeof mess2, "mu=%s\nk=%s\nS=%s\n", hexmu, ks, S);
conn->write(conn, (uchar*)mess2, strlen(mess2));
// recv hash2(g**xy)
if(readstr(conn, mess2) < 0){
writerr(conn, "couldn't read verifier");
goto done;
}
eol = strchr(mess2, '\n');
if(strncmp("k'=", mess2, 3) != 0 || !eol){
writerr(conn, "verifier syntax error");
goto done;
}
kc = mess2+3;
*eol = 0;
shorthash("client", C, S, hexm, hexmu, hexsigma, hexHi, digest);
enc64(ks, sizeof ks, digest, SHA1dlen);
if(strcmp(ks, kc) != 0) {
rc = -2;
goto done;
}
// set session key
shorthash("session", C, S, hexm, hexmu, hexsigma, hexHi, digest);
n = conn->secret(conn, digest, 1);
if(n < 0){
writerr(conn, "can't set secret");
goto done;
}
rc = 0;
done:
if(rc<0 && pw){
pw->failed++;
putPW(pw);
}
if(rc==0 && pw && pw->failed>0){
pw->failed = 0;
putPW(pw);
}
if(pwp)
*pwp = pw;
else
freePW(pw);
free(hexsigma);
free(hexHi);
free(hexmu);
mpfree(y);
mpfree(sigma);
mpfree(mu);
mpfree(m);
mpfree(Hi);
mpfree(H);
return rc;
}

136
src/cmd/secstore/password.c Normal file
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/* password.c */
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <mp.h>
#include <libsec.h>
#include "SConn.h"
#include "secstore.h"
static Biobuf*
openPW(char *id, int mode)
{
Biobuf *b;
int nfn = strlen(SECSTORE_DIR)+strlen(id)+20;
char *fn = emalloc(nfn);
snprint(fn, nfn, "%s/who/%s", SECSTORE_DIR, id);
b = Bopen(fn, mode);
free(fn);
return b;
}
static ulong
mtimePW(char *id)
{
Dir *d;
int nfn = strlen(SECSTORE_DIR)+strlen(id)+20;
char *fn = emalloc(nfn);
ulong mt;
snprint(fn, nfn, "%s/who/%s", SECSTORE_DIR, id);
d = dirstat(fn);
free(fn);
mt = d->mtime;
free(d);
return mt;
}
PW *
getPW(char *id, int dead_or_alive)
{
uint now = time(0);
Biobuf *bin;
PW *pw;
char *f1, *f2; // fields 1, 2 = attribute, value
if((bin = openPW(id, OREAD)) == 0){
id = "FICTITIOUS";
if((bin = openPW(id, OREAD)) == 0){
werrstr("account does not exist");
return nil;
}
}
pw = emalloc(sizeof(*pw));
pw->id = estrdup(id);
pw->status |= Enabled;
while( (f1 = Brdline(bin, '\n')) != 0){
f1[Blinelen(bin)-1] = 0;
for(f2 = f1; *f2 && (*f2!=' ') && (*f2!='\t'); f2++){}
if(*f2)
for(*f2++ = 0; *f2 && (*f2==' ' || *f2=='\t'); f2++){}
if(strcmp(f1, "exp") == 0){
pw->expire = strtoul(f2, 0, 10);
}else if(strcmp(f1, "DISABLED") == 0){
pw->status &= ~Enabled;
}else if(strcmp(f1, "STA") == 0){
pw->status |= STA;
}else if(strcmp(f1, "failed") == 0){
pw->failed = strtoul(f2, 0, 10);
}else if(strcmp(f1, "other") == 0){
pw->other = estrdup(f2);
}else if(strcmp(f1, "PAK-Hi") == 0){
pw->Hi = strtomp(f2, nil, 64, nil);
}
}
Bterm(bin);
if(dead_or_alive)
return pw; // return PW entry for editing, whether currently valid or not
if(pw->expire <= now){
werrstr("account expired");
freePW(pw);
return nil;
}
if((pw->status & Enabled) == 0){
werrstr("account disabled");
freePW(pw);
return nil;
}
if(pw->failed < 10)
return pw; // success
if(now < mtimePW(id)+300){
werrstr("too many failures; try again in five minutes");
freePW(pw);
return nil;
}
pw->failed = 0;
putPW(pw); // reset failed-login-counter after five minutes
return pw;
}
int
putPW(PW *pw)
{
Biobuf *bout;
char *hexHi;
if((bout = openPW(pw->id, OWRITE|OTRUNC)) ==0){
werrstr("can't open PW file");
return -1;
}
Bprint(bout, "exp %lud\n", pw->expire);
if(!(pw->status & Enabled))
Bprint(bout, "DISABLED\n");
if(pw->status & STA)
Bprint(bout, "STA\n");
if(pw->failed)
Bprint(bout, "failed\t%d\n", pw->failed);
if(pw->other)
Bprint(bout,"other\t%s\n", pw->other);
hexHi = mptoa(pw->Hi, 64, nil, 0);
Bprint(bout, "PAK-Hi\t%s\n", hexHi);
free(hexHi);
return 0;
}
void
freePW(PW *pw)
{
if(pw == nil)
return;
free(pw->id);
free(pw->other);
mpfree(pw->Hi);
free(pw);
}

580
src/cmd/secstore/secstore.c Normal file
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@ -0,0 +1,580 @@
/* network login client */
#include <u.h>
#include <libc.h>
#include <mp.h>
#include <libsec.h>
#include <authsrv.h>
#include "SConn.h"
#include "secstore.h"
enum{ CHK = 16, MAXFILES = 100 };
typedef struct AuthConn{
SConn *conn;
char pass[64];
int passlen;
} AuthConn;
int verbose;
Nvrsafe nvr;
void
usage(void)
{
fprint(2, "usage: secstore [-cin] [-g getfile] [-p putfile] [-r rmfile] [-s tcp!server!5356] [-u user] [-v]\n");
exits("usage");
}
static int
getfile(SConn *conn, char *gf, uchar **buf, ulong *buflen, uchar *key, int nkey)
{
int fd = -1;
int i, n, nr, nw, len;
char s[Maxmsg+1];
uchar skey[SHA1dlen], ib[Maxmsg+CHK], *ibr, *ibw, *bufw, *bufe;
AESstate aes;
DigestState *sha;
if(strchr(gf, '/')){
fprint(2, "simple filenames, not paths like %s\n", gf);
return -1;
}
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';
bufw = bufe = nil;
if(readstr(conn, s) < 0){
fprint(2, "remote: %s\n", s);
return -1;
}
len = atoi(s);
if(len == -1){
fprint(2, "remote file %s does not exist\n", gf);
return -1;
}else if(len == -3){
fprint(2, "implausible filesize for %s\n", gf);
return -1;
}else if(len < 0){
fprint(2, "GET refused for %s\n", gf);
return -1;
}
if(buf != nil){
*buflen = len - AESbsize - CHK;
*buf = bufw = emalloc(len);
bufe = bufw + len;
}
/* directory listing */
if(strcmp(gf,".")==0){
if(buf != nil)
*buflen = len;
for(i=0; i < len; i += n){
if((n = conn->read(conn, (uchar*)s, Maxmsg)) <= 0){
fprint(2, "empty file chunk\n");
return -1;
}
if(buf == nil)
write(1, s, n);
else
memmove((*buf)+i, s, n);
}
return 0;
}
/* conn is already encrypted against wiretappers,
but gf is also encrypted against server breakin. */
if(buf == nil && (fd =create(gf, OWRITE, 0600)) < 0){
fprint(2, "can't open %s: %r\n", gf);
return -1;
}
ibr = ibw = ib;
for(nr=0; nr < len;){
if((n = conn->read(conn, ibw, Maxmsg)) <= 0){
fprint(2, "empty file chunk n=%d nr=%d len=%d: %r\n", n, nr, len);
return -1;
}
nr += n;
ibw += n;
if(!aes.setup){ /* first time, read 16 byte IV */
if(n < AESbsize){
fprint(2, "no IV in file\n");
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){
if(buf == nil){
nw = write(fd, ibr, n);
if(nw != n){
fprint(2, "write error on %s", gf);
return -1;
}
}else{
assert(bufw+n <= bufe);
memmove(bufw, ibr, n);
bufw += n;
}
ibr += n;
}
memmove(ib, ibr, ibw-ibr);
ibw = ib + (ibw-ibr);
ibr = ib;
}
if(buf == nil)
close(fd);
n = ibw-ibr;
if((n != CHK) || (memcmp(ib, "XXXXXXXXXXXXXXXX", CHK) != 0)){
fprint(2,"decrypted file failed to authenticate!\n");
return -1;
}
return 0;
}
// This sends a file to the secstore disk that can, in an emergency, be
// decrypted by the program aescbc.c.
static int
putfile(SConn *conn, char *pf, uchar *buf, ulong len, uchar *key, int nkey)
{
int i, n, fd, ivo, bufi, done;
char s[Maxmsg];
uchar skey[SHA1dlen], b[CHK+Maxmsg], IV[AESbsize];
AESstate aes;
DigestState *sha;
/* create initialization vector */
srand(time(0)); /* doesn't need to be unpredictable */
for(i=0; i<AESbsize; i++)
IV[i] = 0xff & rand();
sha = sha1((uchar*)"aescbc file", 11, nil, nil);
sha1(key, nkey, skey, sha);
setupAESstate(&aes, skey, AESbsize, IV);
memset(skey, 0, sizeof skey);
snprint(s, Maxmsg, "PUT %s\n", pf);
conn->write(conn, (uchar*)s, strlen(s));
if(buf == nil){
/* get file size */
if((fd = open(pf, OREAD)) < 0){
fprint(2, "can't open %s: %r\n", pf);
return -1;
}
len = seek(fd, 0, 2);
seek(fd, 0, 0);
} else {
fd = -1;
}
if(len > MAXFILESIZE){
fprint(2, "implausible filesize %ld for %s\n", len, pf);
return -1;
}
/* send file size */
snprint(s, Maxmsg, "%ld", len+AESbsize+CHK);
conn->write(conn, (uchar*)s, strlen(s));
/* send IV and file+XXXXX in Maxmsg chunks */
ivo = AESbsize;
bufi = 0;
memcpy(b, IV, ivo);
for(done = 0; !done; ){
if(buf == nil){
n = read(fd, b+ivo, Maxmsg-ivo);
if(n < 0){
fprint(2, "read error on %s: %r\n", pf);
return -1;
}
}else{
if((n = len - bufi) > Maxmsg-ivo)
n = Maxmsg-ivo;
memcpy(b+ivo, buf+bufi, n);
bufi += n;
}
n += ivo;
ivo = 0;
if(n < Maxmsg){ /* EOF on input; append XX... */
memset(b+n, 'X', CHK);
n += CHK; // might push n>Maxmsg
done = 1;
}
aesCBCencrypt(b, n, &aes);
if(n > Maxmsg){
assert(done==1);
conn->write(conn, b, Maxmsg);
n -= Maxmsg;
memmove(b, b+Maxmsg, n);
}
conn->write(conn, b, n);
}
if(buf == nil)
close(fd);
fprint(2, "saved %ld bytes\n", len);
return 0;
}
static int
removefile(SConn *conn, char *rf)
{
char buf[Maxmsg];
if(strchr(rf, '/')){
fprint(2, "simple filenames, not paths like %s\n", rf);
return -1;
}
snprint(buf, Maxmsg, "RM %s\n", rf);
conn->write(conn, (uchar*)buf, strlen(buf));
return 0;
}
static int
cmd(AuthConn *c, char **gf, int *Gflag, char **pf, char **rf)
{
ulong len;
int rv = -1;
uchar *memfile, *memcur, *memnext;
while(*gf != nil){
if(verbose)
fprint(2, "get %s\n", *gf);
if(getfile(c->conn, *gf, *Gflag ? &memfile : nil, &len, (uchar*)c->pass, c->passlen) < 0)
goto Out;
if(*Gflag){
// write one line at a time, as required by /mnt/factotum/ctl
memcur = memfile;
while(len>0){
memnext = (uchar*)strchr((char*)memcur, '\n');
if(memnext){
write(1, memcur, memnext-memcur+1);
len -= memnext-memcur+1;
memcur = memnext+1;
}else{
write(1, memcur, len);
break;
}
}
free(memfile);
}
gf++;
Gflag++;
}
while(*pf != nil){
if(verbose)
fprint(2, "put %s\n", *pf);
if(putfile(c->conn, *pf, nil, 0, (uchar*)c->pass, c->passlen) < 0)
goto Out;
pf++;
}
while(*rf != nil){
if(verbose)
fprint(2, "rm %s\n", *rf);
if(removefile(c->conn, *rf) < 0)
goto Out;
rf++;
}
c->conn->write(c->conn, (uchar*)"BYE", 3);
rv = 0;
Out:
c->conn->free(c->conn);
return rv;
}
static int
chpasswd(AuthConn *c, char *id)
{
ulong len;
int rv = -1, newpasslen = 0;
mpint *H, *Hi;
uchar *memfile;
char *newpass, *passck;
char *list, *cur, *next, *hexHi;
char *f[8], prompt[128];
H = mpnew(0);
Hi = mpnew(0);
// changing our password is vulnerable to connection failure
for(;;){
snprint(prompt, sizeof(prompt), "new password for %s: ", id);
newpass = getpassm(prompt);
if(newpass == nil)
goto Out;
if(strlen(newpass) >= 7)
break;
else if(strlen(newpass) == 0){
fprint(2, "!password change aborted\n");
goto Out;
}
print("!password must be at least 7 characters\n");
}
newpasslen = strlen(newpass);
snprint(prompt, sizeof(prompt), "retype password: ");
passck = getpassm(prompt);
if(passck == nil){
fprint(2, "getpassmwd failed\n");
goto Out;
}
if(strcmp(passck, newpass) != 0){
fprint(2, "passwords didn't match\n");
goto Out;
}
c->conn->write(c->conn, (uchar*)"CHPASS", strlen("CHPASS"));
hexHi = PAK_Hi(id, newpass, H, Hi);
c->conn->write(c->conn, (uchar*)hexHi, strlen(hexHi));
free(hexHi);
mpfree(H);
mpfree(Hi);
if(getfile(c->conn, ".", (uchar **)(void*)&list, &len, nil, 0) < 0){
fprint(2, "directory listing failed.\n");
goto Out;
}
/* Loop over files and reencrypt them; try to keep going after error */
for(cur=list; (next=strchr(cur, '\n')) != nil; cur=next+1){
*next = '\0';
if(tokenize(cur, f, nelem(f))< 1)
break;
fprint(2, "reencrypting '%s'\n", f[0]);
if(getfile(c->conn, f[0], &memfile, &len, (uchar*)c->pass, c->passlen) < 0){
fprint(2, "getfile of '%s' failed\n", f[0]);
continue;
}
if(putfile(c->conn, f[0], memfile, len, (uchar*)newpass, newpasslen) < 0)
fprint(2, "putfile of '%s' failed\n", f[0]);
free(memfile);
}
free(list);
c->conn->write(c->conn, (uchar*)"BYE", 3);
rv = 0;
Out:
if(newpass != nil){
memset(newpass, 0, newpasslen);
free(newpass);
}
c->conn->free(c->conn);
return rv;
}
static AuthConn*
login(char *id, char *dest, int pass_stdin, int pass_nvram)
{
AuthConn *c;
int fd, n, ntry = 0;
char *S, *PINSTA = nil, *nl, s[Maxmsg+1], *pass;
if(dest == nil){
fprint(2, "tried to login with nil dest\n");
exits("nil dest");
}
c = emalloc(sizeof(*c));
if(pass_nvram){
/* if(readnvram(&nvr, 0) < 0) */
exits("readnvram: %r");
strecpy(c->pass, c->pass+sizeof c->pass, nvr.config);
}
if(pass_stdin){
n = readn(0, s, Maxmsg-2); // so len(PINSTA)<Maxmsg-3
if(n < 1)
exits("no password on standard input");
s[n] = 0;
nl = strchr(s, '\n');
if(nl){
*nl++ = 0;
PINSTA = estrdup(nl);
nl = strchr(PINSTA, '\n');
if(nl)
*nl = 0;
}
strecpy(c->pass, c->pass+sizeof c->pass, s);
}
while(1){
if(verbose)
fprint(2, "dialing %s\n", dest);
if((fd = dial(dest, nil, nil, nil)) < 0){
fprint(2, "can't dial %s\n", dest);
free(c);
return nil;
}
if((c->conn = newSConn(fd)) == nil){
free(c);
return nil;
}
ntry++;
if(!pass_stdin && !pass_nvram){
pass = getpassm("secstore password: ");
if(strlen(pass) >= sizeof c->pass){
fprint(2, "password too long, skipping secstore login\n");
exits("password too long");
}
strcpy(c->pass, pass);
memset(pass, 0, strlen(pass));
free(pass);
}
if(c->pass[0]==0){
fprint(2, "null password, skipping secstore login\n");
exits("no password");
}
if(PAKclient(c->conn, id, c->pass, &S) >= 0)
break;
c->conn->free(c->conn);
if(pass_stdin)
exits("invalid password on standard input");
if(pass_nvram)
exits("invalid password in nvram");
// and let user try retyping the password
if(ntry==3)
fprint(2, "Enter an empty password to quit.\n");
}
c->passlen = strlen(c->pass);
fprint(2, "%s\n", S);
free(S);
if(readstr(c->conn, s) < 0){
c->conn->free(c->conn);
free(c);
return nil;
}
if(strcmp(s, "STA") == 0){
long sn;
if(pass_stdin){
if(PINSTA)
strncpy(s+3, PINSTA, (sizeof s)-3);
else
exits("missing PIN+SecureID on standard input");
free(PINSTA);
}else{
pass = getpassm("STA PIN+SecureID: ");
strncpy(s+3, pass, (sizeof s)-4);
memset(pass, 0, strlen(pass));
free(pass);
}
sn = strlen(s+3);
if(verbose)
fprint(2, "%ld\n", sn);
c->conn->write(c->conn, (uchar*)s, sn+3);
readstr(c->conn, s);
}
if(strcmp(s, "OK") != 0){
fprint(2, "%s\n", s);
c->conn->free(c->conn);
free(c);
return nil;
}
return c;
}
int
main(int argc, char **argv)
{
int chpass = 0, pass_stdin = 0, pass_nvram = 0, rc;
int ngfile = 0, npfile = 0, nrfile = 0, Gflag[MAXFILES+1];
char *gfile[MAXFILES], *pfile[MAXFILES], *rfile[MAXFILES];
char *serve, *tcpserve, *user;
AuthConn *c;
serve = "$auth";
user = getenv("USER");
memset(Gflag, 0, sizeof Gflag);
fmtinstall('B', mpfmt);
fmtinstall('H', encodefmt);
ARGBEGIN{
case 'c':
chpass = 1;
break;
case 'G':
Gflag[ngfile]++;
/* fall through */
case 'g':
if(ngfile >= MAXFILES)
exits("too many gfiles");
gfile[ngfile++] = ARGF();
if(gfile[ngfile-1] == nil)
usage();
break;
case 'i':
pass_stdin = 1;
break;
case 'n':
pass_nvram = 1;
break;
case 'p':
if(npfile >= MAXFILES)
exits("too many pfiles");
pfile[npfile++] = ARGF();
if(pfile[npfile-1] == nil)
usage();
break;
case 'r':
if(nrfile >= MAXFILES)
exits("too many rfiles");
rfile[nrfile++] = ARGF();
if(rfile[nrfile-1] == nil)
usage();
break;
case 's':
serve = EARGF(usage());
break;
case 'u':
user = EARGF(usage());
break;
case 'v':
verbose++;
break;
default:
usage();
break;
}ARGEND;
gfile[ngfile] = nil;
pfile[npfile] = nil;
rfile[nrfile] = nil;
if(argc!=0 || user==nil)
usage();
if(chpass && (ngfile || npfile || nrfile)){
fprint(2, "Get, put, and remove invalid with password change.\n");
exits("usage");
}
rc = strlen(serve)+sizeof("tcp!!99990");
tcpserve = emalloc(rc);
if(strchr(serve,'!'))
strcpy(tcpserve, serve);
else
snprint(tcpserve, rc, "tcp!%s!5356", serve);
c = login(user, tcpserve, pass_stdin, pass_nvram);
free(tcpserve);
if(c == nil){
fprint(2, "secstore authentication failed\n");
exits("secstore authentication failed");
}
if(chpass)
rc = chpasswd(c, user);
else
rc = cmd(c, gfile, Gflag, pfile, rfile);
if(rc < 0){
fprint(2, "secstore cmd failed\n");
exits("secstore cmd failed");
}
exits("");
return 0;
}

30
src/cmd/secstore/secstore.h Normal file
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@ -0,0 +1,30 @@
enum{ MAXFILESIZE = 10*1024*1024 };
enum{// PW status bits
Enabled = (1<<0),
STA = (1<<1), // extra SecurID step
};
typedef struct PW {
char *id; // user id
ulong expire; // expiration time (epoch seconds)
ushort status; // Enabled, STA, ...
ushort failed; // number of failed login attempts
char *other; // other information, e.g. sponsor
mpint *Hi; // H(passphrase)^-1 mod p
} PW;
PW *getPW(char *, int);
int putPW(PW *);
void freePW(PW *);
char* getpassm(const char*);
// *client: SConn, client name, passphrase
// *server: SConn, (partial) 1st msg, PW entry
// *setpass: Username, hashed passphrase, PW entry
int PAKclient(SConn *, char *, char *, char **);
int PAKserver(SConn *, char *, char *, PW **);
char *PAK_Hi(char *, char *, mpint *, mpint *);
#define LOG "secstore"
#define SECSTORE_DIR "/adm/secstore"

38
src/cmd/secstore/util.c Normal file
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#include <u.h>
#include <libc.h>
void *
emalloc(ulong n)
{
void *p = malloc(n);
if(p == nil)
sysfatal("emalloc");
memset(p, 0, n);
return p;
}
void *
erealloc(void *p, ulong n)
{
if ((p = realloc(p, n)) == nil)
sysfatal("erealloc");
return p;
}
char *
estrdup(char *s)
{
if ((s = strdup(s)) == nil)
sysfatal("estrdup");
return s;
}
char *
getpassm(char *prompt)
{
char *p = getpass(prompt);
if(p == nil || (p = strdup(p)) == nil)
sysfatal("getpassm");
return p;
}