3 * Request a key over UDP, or respond to such a request
5 * (c) 2012 Mark Wooding
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of udpkey.
12 * The udpkey program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * The udpkey program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with udpkey; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
36 #include <sys/types.h>
43 #include <sys/socket.h>
44 #include <arpa/inet.h>
45 #include <netinet/in.h>
48 #include <mLib/alloc.h>
50 #include <mLib/daemonize.h>
51 #include <mLib/dstr.h>
52 #include <mLib/fdflags.h>
53 #include <mLib/fwatch.h>
55 #include <mLib/mdwopt.h>
56 #include <mLib/quis.h>
57 #include <mLib/report.h>
61 #include <catacomb/buf.h>
62 #include <catacomb/dh.h>
63 #include <catacomb/ec.h>
64 #include <catacomb/ec-keys.h>
65 #include <catacomb/gcipher.h>
66 #include <catacomb/gmac.h>
67 #include <catacomb/group.h>
68 #include <catacomb/key.h>
69 #include <catacomb/mp.h>
70 #include <catacomb/mprand.h>
71 #include <catacomb/noise.h>
72 #include <catacomb/rand.h>
74 #include <catacomb/rijndael-counter.h>
75 #include <catacomb/sha256.h>
83 /*---- Static variables ---------------------------------------------------*/
85 static unsigned flags
= 0;
92 static unsigned char ibuf
[BUFSZ
], obuf
[BUFSZ
];
95 static const char *kfname
= "keyring";
96 static const char *pidfile
;
97 static fwatch kfwatch
;
100 /*----- Miscellaneous utilities -------------------------------------------*/
102 /* Resolve NAME, storing the address in *ADDR. Exit on error. */
103 static void resolve(const char *name
, struct in_addr
*addr
)
107 if ((h
= gethostbyname(name
)) == 0)
108 die(1, "failed to resolve `%s': %s", name
, hstrerror(h_errno
));
109 if (h
->h_addrtype
!= AF_INET
)
110 die(1, "unexpected address type %d", h
->h_addrtype
);
111 memcpy(addr
, h
->h_addr
, sizeof(struct in_addr
));
114 /* Convert PORT to a port number (in host byte order). Exit on error. */
115 static unsigned short getport(const char *port
)
122 if (!isdigit(*port
) ||
123 (i
= strtoul(port
, &q
, 0)) == 0 ||
124 i
>= 65536 || *q
|| errno
)
125 die(1, "invalid port number `%s'", port
);
127 return ((unsigned short)i
);
130 /* Read the file named by NAME into a buffer -- or at least an initial
131 * portion of it; set *P to the start and *SZ to the length. Return -1 if it
132 * didn't work. The buffer doesn't need to be freed: the data is stashed in
135 static int snarf(const char *name
, void **p
, size_t *sz
)
140 if ((fd
= open(name
, O_RDONLY
)) < 0) return (-1);
141 n
= read(fd
, ibuf
, sizeof(ibuf
));
143 if (n
< 0) return (-1);
148 /* Complain about something. If f_syslog is set then complain to that;
149 * otherwise write to stderr. Don't use `%m' because that won't work when
152 static void complain(int sev
, const char *msg
, ...)
157 if (flags
& f_syslog
)
158 vsyslog(sev
, msg
, ap
);
160 fprintf(stderr
, "%s: ", QUIS
);
161 vfprintf(stderr
, msg
, ap
);
166 /*----- Reading key data --------------------------------------------------*/
173 const gcmac
*mc
; size_t tagsz
;
177 /* Clear a kinfo structure so it can be freed without trouble. */
178 static void k_init(struct kinfo
*k
) { k
->g
= 0; k
->x
= 0; k
->X
= 0; }
180 /* Free a kinfo structure. This is safe on any initialized kinfo
183 static void k_free(struct kinfo
*k
)
185 if (k
->X
) { G_DESTROY(k
->g
, k
->X
); k
->X
= 0; }
186 if (k
->x
) { MP_DROP(k
->x
); k
->x
= 0; }
187 if (k
->g
) { G_DESTROYGROUP(k
->g
); k
->g
= 0; }
190 /* Empty macro arguments are forbidden. But arguments are expended during
191 * replacement, not while the call is being processed, so this hack is OK.
192 * Unfortunately, if a potentially empty argument is passed on to another
193 * macro then it needs to be guarded with a use of EMPTY too...
197 /* Table of key types. Entries have the form
199 * _(name, NAME, SETGROUP, SETPRIV, SETPUB)
201 * The name and NAME are lower- and uppercase names for the type used for
202 * constructing various type name constant names. The code fragment SETGROUP
203 * initializes k->g given the name_{pub,priv} structure in p; SETPRIV and
204 * SETPUB set up k->x and k->X respectively. (In this last case, k->X will
205 * have been created as a group element already.)
207 #define KEYTYPES(_) \
210 { k->g = group_prime(&p.dp); }, \
211 { k->x = MP_COPY(p.x); }, \
212 { if (G_FROMINT(k->g, k->X, p.y)) { \
213 complain(LOG_ERR, "bad public key in `%s'", t->buf); \
219 { ec_info ei; const char *e; \
220 if ((e = ec_getinfo(&ei, p.cstr)) != 0) { \
221 complain(LOG_ERR, "bad elliptic curve in `%s': %s", t->buf, e); \
224 k->g = group_ec(&ei); \
226 { k->x = MP_COPY(p.x); }, \
227 { if (G_FROMEC(k->g, k->X, &p.p)) { \
228 complain(LOG_ERR, "bad public point in `%s'", t->buf); \
233 /* Define load_tywhich, where which is `pub' or `priv', to load a public or
234 * private key. Other parameters are as for the KEYTYPES list above.
236 #define KLOAD(ty, TY, which, WHICH, setgroup, setpriv, setpub) \
237 static int load_##ty##which(key_data *kd, struct kinfo *k, dstr *t) \
239 key_packstruct kps[TY##_##WHICH##FETCHSZ]; \
244 /* Extract the key data from the keydata. */ \
245 kp = key_fetchinit(ty##_##which##fetch, kps, &p); \
246 if ((rc = key_unpack(kp, kd, t)) != 0) { \
247 complain(LOG_ERR, "failed to unpack key `%s': %s", \
248 t->buf, key_strerror(rc)); \
252 /* Extract the components as abstract group elements. */ \
255 k->X = G_CREATE(k->g); \
258 /* Dispose of stuff we don't need. */ \
262 /* Tidy up after mishaps. */ \
269 /* Map over the KEYTYPES to declare the load_tywhich functions using KLOAD
272 #define KEYTYPE_KLOAD(ty, TY, setgroup, setpriv, setpub) \
273 KLOAD(ty, TY, priv, PRIV, setgroup, setpriv, \
274 { G_EXP(k->g, k->X, k->g->g, k->x); }) \
275 KLOAD(ty, TY, pub, PUB, setgroup, { }, setpub)
276 KEYTYPES(KEYTYPE_KLOAD
)
278 /* Define a table of group key-loading operations. */
281 int (*loadpriv
)(key_data
*, struct kinfo
*, dstr
*);
282 int (*loadpub
)(key_data
*, struct kinfo
*, dstr
*);
285 static const struct kload_ops kload_ops
[] = {
286 #define KEYTYPE_OPS(ty, TY, setgroup, setpriv, setpub) \
287 { #ty, load_##ty##priv, load_##ty##pub },
288 KEYTYPES(KEYTYPE_OPS
)
292 /* Load a private or public (indicated by PRIVP) key named TAG into a kinfo
293 * structure K. Also fill in the cipher suite selections extracted from the
296 static int loadkey(const char *tag
, struct kinfo
*k
, int privp
)
298 const struct kload_ops
*ops
;
299 dstr d
= DSTR_INIT
, dd
= DSTR_INIT
;
307 /* Find the key data. */
308 if (key_qtag(kf
, tag
, &d
, &ky
, &kd
)) {
309 complain(LOG_ERR
, "unknown key tag `%s'", tag
);
313 /* Find the key's group type and locate the group operations. */
314 ty
= key_getattr(kf
, ky
, "group");
315 if (!ty
&& strncmp(ky
->type
, "udpkey-", 7) == 0) ty
= ky
->type
+ 7;
317 complain(LOG_ERR
, "no group type for key %s", d
.buf
);
320 for (ops
= kload_ops
; ops
->name
; ops
++) {
321 if (strcmp(ty
, ops
->name
) == 0)
324 complain(LOG_ERR
, "unknown group type `%s' in key %s", ty
, d
.buf
);
328 /* Extract the key data into an appropriately abstract form. */
329 k
->g
= 0; k
->x
= 0; k
->X
= 0;
330 if ((rc
= (privp ? ops
->loadpriv
: ops
->loadpub
)(*kd
, k
, &d
)) != 0)
333 /* Extract the chosen symmetric cipher. */
334 if ((p
= key_getattr(kf
, ky
, "cipher")) == 0)
335 k
->cc
= &rijndael_counter
;
336 else if ((k
->cc
= gcipher_byname(p
)) == 0) {
337 complain(LOG_ERR
, "unknown cipher `%s' in key %s", p
, d
.buf
);
341 /* And the chosen hash function. */
342 if ((p
= key_getattr(kf
, ky
, "hash")) == 0)
344 else if ((k
->hc
= ghash_byname(p
)) == 0) {
345 complain(LOG_ERR
, "unknown hash `%s' in key %s", p
, d
.buf
);
349 /* And finally a MAC. This is more fiddly because we must handle (a)
350 * truncation and (b) defaulting based on the hash.
352 if ((p
= key_getattr(kf
, ky
, "mac")) == 0)
353 dstr_putf(&dd
, "%s-hmac", k
->hc
->name
);
356 if ((q
= strchr(dd
.buf
, '/')) != 0) *q
++ = 0;
358 if ((k
->mc
= gmac_byname(dd
.buf
)) == 0) {
359 complain(LOG_ERR
, "unknown mac `%s' in key %s", dd
.buf
, d
.buf
);
363 k
->tagsz
= k
->mc
->hashsz
/2;
366 if (tsz
<= 0 || tsz
%8 || tsz
/8 > k
->mc
->hashsz
) {
367 complain(LOG_ERR
, "bad tag size for mac `%s' in key %s",
368 q
, k
->mc
->name
, d
.buf
);
386 static void keymoan(const char *file
, int line
, const char *err
, void *p
)
387 { complain(LOG_ERR
, "%s:%d: %s", file
, line
, err
); }
389 /* Update the keyring `kf' if the file has been changed since we last looked.
391 static void kfupdate(void)
395 if (!fwatch_update(&kfwatch
, kfname
)) return;
396 kfnew
= CREATE(key_file
);
397 if (key_open(kfnew
, kfname
, KOPEN_READ
, keymoan
, 0)) {
406 /*----- Low-level crypto operations ---------------------------------------*/
408 /* Derive a key, writing its address to *KK and size to *N. The size is
409 * compatible with the keysz rules KSZ. It is generated for the purpose of
410 * keying a WHAT (used for key separation and in error messages), and NAME is
411 * the name of the specific instance (e.g., `twofish-counter') from the class
412 * name. The kinfo structure K tells us which algorithms to use for the
413 * derivation. The group elements U and Z are the cryptographic inputs
414 * for the derivation.
416 * Basically all we do is compute H(what || U || Z).
418 static int derive(struct kinfo
*k
, ge
*U
, ge
*Z
,
419 const char *what
, const char *name
, const octet
*ksz
,
420 octet
**kk
, size_t *n
)
426 /* Find a suitable key size. */
427 if ((*n
= keysz(k
->hc
->hashsz
, ksz
)) == 0) {
429 "failed to find suitable key size for %s `%s' and hash `%s'",
430 what
, name
, k
->hc
->name
);
434 /* Build the hash preimage. */
435 buf_init(&b
, obuf
, sizeof(obuf
));
436 buf_put(&b
, "udpkey-", 7);
437 buf_putstrz(&b
, what
);
438 G_TORAW(k
->g
, &b
, U
);
439 G_TORAW(k
->g
, &b
, Z
);
441 complain(LOG_ERR
, "overflow while deriving key (prepare preimage)!");
445 /* Derive the output key. */
447 GH_HASH(h
, BBASE(&b
), BLEN(&b
));
448 buf_init(&b
, obuf
, sizeof(obuf
));
449 if ((p
= buf_get(&b
, h
->ops
->c
->hashsz
)) == 0) {
450 complain(LOG_ERR
, "overflow while deriving key (output hash)!");
461 static void debug_mp(const char *what
, mp
*x
)
462 { fprintf(stderr
, "%s: *** ", QUIS
); MP_EPRINT(what
, x
); }
463 static void debug_ge(const char *what
, group
*g
, ge
*X
)
465 fprintf(stderr
, "%s: *** %s = ", QUIS
, what
);
466 group_writefile(g
, X
, stderr
);
471 /*----- Listening for requests --------------------------------------------*/
473 /* Rate limiting parameters.
475 * There's a probabilistic rate-limiting mechanism. A counter starts at 0.
476 * Every time we oricess a request, we increment the counter. The counter
477 * drops by RATE_REFILL every second. If the counter is below RATE_CREDIT
478 * then the request is processed; otherwise it is processed with probability
479 * 1/(counter - RATE_CREDIT).
481 #define RATE_REFILL 10 /* Credits per second. */
482 #define RATE_CREDIT 1000 /* Initial credit. */
484 static int dolisten(int argc
, char *argv
[])
493 struct sockaddr_in sin
;
498 dstr d
= DSTR_INIT
, dd
= DSTR_INIT
;
502 mp
*r
= MP_NEW
, *v
= MP_NEW
;
503 ge
*R
= 0, *U
= 0, *V
= 0, *W
= 0, *Y
= 0, *Z
= 0;
510 unsigned bucket
= 0, toks
;
511 time_t last
= 0, now
;
513 /* Set up the socket address. */
514 sin
.sin_family
= AF_INET
;
515 aspec
= xstrdup(argv
[0]);
516 if ((p
= strchr(aspec
, ':')) == 0) {
518 sin
.sin_addr
.s_addr
= INADDR_ANY
;
521 resolve(aspec
, &sin
.sin_addr
);
523 sin
.sin_port
= htons(getport(p
));
525 /* Create and set up the socket itself. */
526 if ((sk
= socket(PF_INET
, SOCK_DGRAM
, 0)) < 0 ||
527 fdflags(sk
, O_NONBLOCK
, O_NONBLOCK
, FD_CLOEXEC
, FD_CLOEXEC
) ||
528 bind(sk
, (struct sockaddr
*)&sin
, sizeof(sin
)))
529 die(1, "failed to create socket: %s", strerror(errno
));
531 /* That's enough initialization. If we should fork, then do that. */
532 if (flags
& f_daemon
) {
533 if (pidfile
&& (fp
= fopen(pidfile
, "w")) == 0)
534 die(1, "failed to open pidfile `%s': %s", pidfile
, strerror(errno
));
535 openlog(QUIS
, LOG_PID
, LOG_DAEMON
);
537 die(1, "failed to become background process: %s", strerror(errno
));
538 if (pidfile
) { fprintf(fp
, "%ld\n", (long)getpid()); fclose(fp
); }
544 /* Clear out the key state. */
547 /* Wait for something to happen. */
550 if (select(sk
+ 1, &fdin
, 0, 0, 0) < 0)
551 die(1, "select failed: %s", strerror(errno
));
552 noise_timer(RAND_GLOBAL
);
554 /* Fetch a packet. */
556 n
= recvfrom(sk
, ibuf
, sizeof(ibuf
), 0, (struct sockaddr
*)&sin
, &len
);
558 if (errno
!= EAGAIN
&& errno
!= EINTR
)
559 complain(LOG_ERR
, "unexpected receive error: %s", strerror(errno
));
563 /* Refill the bucket, and see whether we should reject this packet. */
565 if (bucket
&& now
!= last
) {
566 toks
= (now
- last
)*RATE_REFILL
;
567 bucket
= bucket
< toks ?
0 : bucket
- toks
;
570 if (bucket
> RATE_CREDIT
&&
571 grand_range(&rand_global
, bucket
- RATE_CREDIT
))
575 /* Set up the input buffer for parsing the request. */
576 buf_init(&bin
, ibuf
, n
);
578 /* Extract the key tag name. */
579 if ((p
= buf_getmemz(&bin
, &sz
)) == 0) {
580 complain(LOG_WARNING
, "invalid key tag from %s:%d",
581 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
587 if (key_qtag(kf
, p
, &d
, &ky
, &kkd
)) {
588 complain(LOG_WARNING
, "unknown key tag `%s' from %s:%d",
589 p
, inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
593 /* And make sure that it has the right shape. */
594 if ((ky
->k
->e
& KF_ENCMASK
) != KENC_BINARY
) {
595 complain(LOG_ERR
, "key %s is not plain binary data", d
.buf
);
599 /* Find the list of clients, and look up the caller's address in the
600 * list. Entries have the form ADDRESS[/LEN][=TAG] and are separated by
603 if ((pp
= key_getattr(kf
, ky
, "clients")) == 0) {
604 complain(LOG_WARNING
,
605 "key %s requested from %s:%d has no `clients' attribute",
606 d
.buf
, inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
613 while (isdigit((unsigned char)*q
) || *q
== '.') q
++;
615 if (!inet_aton(p
, &in
)) goto skip
;
620 while (isdigit((unsigned char)*q
)) q
++;
624 if (((sin
.sin_addr
.s_addr
^ in
.s_addr
) &
625 (0xffffffff << (32 - mlen
))) == 0)
630 while (*p
&& *p
!= ';') p
++;
633 complain(LOG_WARNING
, "access to key %s denied to %s:%d",
634 d
.buf
, inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
638 /* Build a tag name for the caller's KEM key, either from the client
639 * match or the source address.
643 dstr_puts(&dd
, "client-");
644 dstr_puts(&dd
, inet_ntoa(sin
.sin_addr
));
648 while (*q
&& *q
!= ';') q
++;
649 if (*q
== ';') *q
++ = 0;
652 /* Report the match. */
653 complain(LOG_NOTICE
, "client %s:%d (`%s') requests key %s",
654 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
), p
, d
.buf
);
656 /* Load the KEM key. */
657 if (loadkey(p
, &k
, 0)) goto again
;
658 D( debug_ge("X", k
.g
, k
.X
); )
660 /* Read the caller's ephemeral key. */
661 R
= G_CREATE(k
.g
); W
= G_CREATE(k
.g
);
662 U
= G_CREATE(k
.g
); V
= G_CREATE(k
.g
);
663 Y
= G_CREATE(k
.g
); Z
= G_CREATE(k
.g
);
664 if (G_FROMBUF(k
.g
, &bin
, U
)) {
665 complain(LOG_WARNING
, "failed to read ephemeral vector from %s:%d",
666 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
669 D( debug_ge("U", k
.g
, U
); )
671 complain(LOG_WARNING
, "trailing junk in request from %s:%d",
672 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
676 /* Ephemeral Diffie--Hellman. Choose v in GF(q) at random; compute
677 * V = v P and -Y = (-v) U.
679 v
= mprand_range(v
, k
.g
->r
, &rand_global
, 0);
680 G_EXP(k
.g
, V
, k
.g
->g
, v
);
681 D( debug_mp("v", v
); debug_ge("V", k
.g
, V
); )
682 v
= mp_sub(v
, k
.g
->r
, v
);
684 D( debug_ge("-Y", k
.g
, Y
); )
686 /* DLIES. Choose r in GF(q) at random; compute R = r P and Z = r X.
687 * Mask the clue R as W = R - Y. (Doing the subtraction here makes life
688 * easier at the other end, since we can determine -Y by negating v
689 * whereas the recipient must subtract vectors which may be less
692 r
= mprand_range(r
, k
.g
->r
, &rand_global
, 0);
693 G_EXP(k
.g
, R
, k
.g
->g
, r
);
694 D( debug_mp("r", r
); debug_ge("R", k
.g
, R
); )
695 G_EXP(k
.g
, Z
, k
.X
, r
);
697 D( debug_ge("Z", k
.g
, Z
); debug_ge("W", k
.g
, W
); )
699 /* Derive encryption and integrity keys. */
700 derive(&k
, R
, Z
, "cipher", k
.cc
->name
, k
.cc
->keysz
, &kk
, &ksz
);
701 c
= GC_INIT(k
.cc
, kk
, ksz
);
702 derive(&k
, R
, Z
, "mac", k
.mc
->name
, k
.mc
->keysz
, &kk
, &ksz
);
703 m
= GM_KEY(k
.mc
, kk
, ksz
);
705 /* Build the ciphertext and compute a MAC tag over it. */
706 buf_init(&bout
, obuf
, sizeof(obuf
));
707 if (G_TOBUF(k
.g
, &bout
, V
) ||
708 G_TOBUF(k
.g
, &bout
, W
))
710 if ((t
= buf_get(&bout
, k
.tagsz
)) == 0) goto bad
;
712 if (BENSURE(&bout
, sz
)) goto bad
;
713 GC_ENCRYPT(c
, ky
->k
->u
.k
.k
, BCUR(&bout
), sz
);
715 GH_HASH(h
, BCUR(&bout
), sz
);
716 tt
= GH_DONE(h
, 0); memcpy(t
, tt
, k
.tagsz
);
719 /* Send the reply packet back to the caller. */
720 if (sendto(sk
, BBASE(&bout
), BLEN(&bout
), 0,
721 (struct sockaddr
*)&sin
, len
) < 0) {
722 complain(LOG_ERR
, "failed to send response to %s:%d: %s",
723 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
),
731 /* Report a problem building the reply. */
732 complain(LOG_ERR
, "failed to construct response to %s:%d",
733 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
736 /* Free stuff for the next iteration. */
737 DRESET(&d
); DRESET(&dd
);
738 if (R
) { G_DESTROY(k
.g
, R
); R
= 0; }
739 if (U
) { G_DESTROY(k
.g
, U
); U
= 0; }
740 if (V
) { G_DESTROY(k
.g
, V
); V
= 0; }
741 if (W
) { G_DESTROY(k
.g
, W
); W
= 0; }
742 if (Y
) { G_DESTROY(k
.g
, Y
); Y
= 0; }
743 if (Z
) { G_DESTROY(k
.g
, Z
); Z
= 0; }
744 if (c
) { GC_DESTROY(c
); c
= 0; }
745 if (m
) { GM_DESTROY(m
); m
= 0; }
746 if (h
) { GH_DESTROY(h
); h
= 0; }
753 /*----- Sending requests and processing responses -------------------------*/
764 struct sockaddr_in sin
;
771 /* Record a successful fetch of key material for a query Q. The data starts
772 * at K and is SZ bytes long. The data is copied: it's safe to overwrite it.
774 static void donequery(struct query
*q
, const void *k
, size_t sz
)
775 { q
->k
= xmalloc(sz
); memcpy(q
->k
, k
, sz
); q
->sz
= sz
; nq
--; }
777 /* Initialize a query to a remote server. */
778 static struct query
*qinit_net(const char *tag
, const char *spec
)
781 struct server
*s
, **stail
;
782 dstr d
= DSTR_INIT
, dd
= DSTR_INIT
;
786 /* Allocate the query block. */
787 q
= CREATE(struct query
);
790 /* Put the spec somewhere we can hack at it. */
794 /* Parse the query spec. Entries have the form ADDRESS:PORT[=TAG][#HASH]
795 * and are separated by `;'.
799 /* Allocate a new server node. */
800 s
= CREATE(struct server
);
801 s
->sin
.sin_family
= AF_INET
;
803 /* Extract the server address. */
804 if ((pp
= strchr(p
, ':')) == 0)
805 die(1, "invalid syntax: missing `:PORT'");
807 resolve(p
, &s
->sin
.sin_addr
);
809 /* Extract the port number. */
811 while (isdigit((unsigned char)*pp
)) pp
++;
813 s
->sin
.sin_port
= htons(getport(p
));
815 /* If there's a key tag then extract that; otherwise use a default. */
820 pp
+= strcspn(pp
, ";#");
823 if (loadkey(p
, &s
->k
, 1)) exit(1);
824 D( debug_mp("x", s
->k
.x
); debug_ge("X", s
->k
.g
, s
->k
.X
); )
826 /* Choose an ephemeral private key u. Let x be our private key. We
827 * compute U = u P and transmit this.
829 s
->u
= mprand_range(MP_NEW
, s
->k
.g
->r
, &rand_global
, 0);
830 s
->U
= G_CREATE(s
->k
.g
);
831 G_EXP(s
->k
.g
, s
->U
, s
->k
.g
->g
, s
->u
);
832 D( debug_mp("u", s
->u
); debug_ge("U", s
->k
.g
, s
->U
); )
834 /* Link the server on. */
835 *stail
= s
; stail
= &s
->next
;
837 /* If there's a trailing hash then extract it. */
842 while (*pp
== '-' || isxdigit((unsigned char)*pp
)) pp
++;
845 hex_decode(&hc
, p
, pp
- p
, &dd
);
846 if (dd
.len
!= s
->k
.hc
->hashsz
) die(1, "incorrect hash length");
847 s
->h
= xmalloc(dd
.len
);
848 memcpy(s
->h
, dd
.buf
, dd
.len
);
852 /* If there are more servers, then continue parsing. */
854 else if (ch
!= ';') die(1, "invalid syntax: expected `;'");
858 /* Terminate the server list and return. */
866 /* Handle a `query' to a local file. */
867 static struct query
*qinit_file(const char *tag
, const char *file
)
873 /* Snarf the file. */
874 q
= CREATE(struct query
);
875 if (snarf(file
, &k
, &sz
))
876 die(1, "failed to read `%s': %s", file
, strerror(errno
));
882 /* Reransmission and timeout parameters. */
883 #define TO_NEXT(t) (((t) + 2)*4/3) /* Timeout growth function */
884 #define TO_MAX 30 /* When to give up */
886 static int doquery(int argc
, char *argv
[])
888 struct query
*q
= 0, *qq
, **qtail
= &qq
;
889 struct server
*s
= 0;
890 const char *tag
= argv
[0];
895 struct timeval now
, when
, tv
;
896 struct sockaddr_in sin
;
897 ge
*R
, *V
= 0, *W
= 0, *Y
= 0, *Z
= 0;
908 /* Create a socket. We just use the one socket for everything. We don't
909 * care which port we get allocated.
911 if ((sk
= socket(PF_INET
, SOCK_DGRAM
, 0)) < 0 ||
912 fdflags(sk
, O_NONBLOCK
, O_NONBLOCK
, FD_CLOEXEC
, FD_CLOEXEC
))
913 die(1, "failed to create socket: %s", strerror(errno
));
915 /* Parse the query target specifications. The adjustments of `nq' aren't
916 * in the right order but that doesn't matter.
918 for (i
= 1; i
< argc
; i
++) {
919 if (*argv
[i
] == '.' || *argv
[i
] == '/') q
= qinit_file(tag
, argv
[i
]);
920 else if (strchr(argv
[i
], ':')) q
= qinit_net(tag
, argv
[i
]);
921 else die(1, "unrecognized query target `%s'", argv
[i
]);
922 *qtail
= q
; qtail
= &q
->next
; nq
++;
926 /* Find the current time so we can compute retransmission times properly.
928 gettimeofday(&now
, 0);
931 /* Continue retransmitting until we have all the answers. */
934 /* Work out when we next want to wake up. */
935 if (TV_CMP(&now
, >=, &when
)) {
937 if (next
>= TO_MAX
) die(1, "no responses: giving up");
938 next
= TO_NEXT(next
);
939 TV_ADDL(&when
, &when
, next
, 0);
940 } while (TV_CMP(&when
, <=, &now
));
941 for (q
= qq
; q
; q
= q
->next
) {
943 for (s
= q
->s
; s
; s
= s
->next
) {
944 buf_init(&bout
, obuf
, sizeof(obuf
));
945 buf_putstrz(&bout
, tag
);
946 G_TOBUF(s
->k
.g
, &bout
, s
->U
);
948 moan("overflow while constructing request!");
951 sendto(sk
, BBASE(&bout
), BLEN(&bout
), 0,
952 (struct sockaddr
*)&s
->sin
, sizeof(s
->sin
));
957 /* Wait until something interesting happens. */
960 TV_SUB(&tv
, &when
, &now
);
961 if (select(sk
+ 1, &fdin
, 0, 0, &tv
) < 0)
962 die(1, "select failed: %s", strerror(errno
));
963 gettimeofday(&now
, 0);
965 /* If we have an input event, process incoming packets. */
966 if (FD_ISSET(sk
, &fdin
)) {
969 /* Read a packet and capture its address. */
971 nn
= recvfrom(sk
, ibuf
, sizeof(ibuf
), 0,
972 (struct sockaddr
*)&sin
, &len
);
974 if (errno
== EAGAIN
) break;
975 else if (errno
== EINTR
) continue;
977 moan("error receiving reply: %s", strerror(errno
));
982 /* Wee whether this corresponds to any of our servers. Don't just
983 * check the active servers, since this may be late replies caused by
984 * retransmissions or similar.
986 for (q
= qq
; q
; q
= q
->next
) {
987 for (s
= q
->s
; s
; s
= s
->next
) {
988 if (s
->sin
.sin_addr
.s_addr
== sin
.sin_addr
.s_addr
&&
989 s
->sin
.sin_port
== sin
.sin_port
)
993 moan("received reply from unexpected source %s:%d",
994 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
998 /* If the query we found has now been satisfied, ignore this packet.
1000 if (q
->k
) goto again
;
1002 /* Start parsing the reply. */
1003 buf_init(&bin
, ibuf
, nn
);
1004 R
= G_CREATE(s
->k
.g
);
1005 V
= G_CREATE(s
->k
.g
); W
= G_CREATE(s
->k
.g
);
1006 Y
= G_CREATE(s
->k
.g
); Z
= G_CREATE(s
->k
.g
);
1007 if (G_FROMBUF(s
->k
.g
, &bin
, V
)) {
1008 moan("invalid Diffie--Hellman vector from %s:%d",
1009 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
1012 if (G_FROMBUF(s
->k
.g
, &bin
, W
)) {
1013 moan("invalid clue vector from %s:%d",
1014 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
1017 D( debug_ge("V", s
->k
.g
, V
); debug_ge("W", s
->k
.g
, W
); )
1019 /* We have V and W from the server; determine Y = u V, R = W + Y and
1020 * Z = x R, and then derive the symmetric keys.
1022 G_EXP(s
->k
.g
, Y
, V
, s
->u
);
1023 G_MUL(s
->k
.g
, R
, W
, Y
);
1024 G_EXP(s
->k
.g
, Z
, R
, s
->k
.x
);
1025 D( debug_ge("R", s
->k
.g
, R
);
1026 debug_ge("Y", s
->k
.g
, Y
);
1027 debug_ge("Z", s
->k
.g
, Z
); )
1028 derive(&s
->k
, R
, Z
, "cipher", s
->k
.cc
->name
, s
->k
.cc
->keysz
,
1030 c
= GC_INIT(s
->k
.cc
, kk
, ksz
);
1031 derive(&s
->k
, R
, Z
, "mac", s
->k
.cc
->name
, s
->k
.cc
->keysz
,
1033 m
= GM_KEY(s
->k
.mc
, kk
, ksz
);
1035 /* Find where the MAC tag is. */
1036 if ((t
= buf_get(&bin
, s
->k
.tagsz
)) == 0) {
1037 moan("missing tag from %s:%d",
1038 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
1042 /* Check the integrity of the ciphertext against the tag. */
1043 p
= BCUR(&bin
); n
= BLEFT(&bin
);
1047 if (memcmp(t
, tt
, s
->k
.tagsz
) != 0) {
1048 moan("incorrect tag from %s:%d",
1049 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
1053 /* Decrypt the result and declare this server done. */
1054 GC_DECRYPT(c
, p
, p
, n
);
1057 h
= GH_INIT(s
->k
.hc
);
1060 if (memcmp(tt
, s
->h
, h
->ops
->c
->hashsz
) != 0) {
1061 moan("response from %s:%d doesn't match hash",
1062 inet_ntoa(sin
.sin_addr
), ntohs(sin
.sin_port
));
1069 /* Tidy things up for the next run through. */
1070 if (R
) { G_DESTROY(s
->k
.g
, R
); R
= 0; }
1071 if (V
) { G_DESTROY(s
->k
.g
, V
); V
= 0; }
1072 if (W
) { G_DESTROY(s
->k
.g
, W
); W
= 0; }
1073 if (Y
) { G_DESTROY(s
->k
.g
, Y
); Y
= 0; }
1074 if (Z
) { G_DESTROY(s
->k
.g
, Z
); Z
= 0; }
1075 if (c
) { GC_DESTROY(c
); c
= 0; }
1076 if (m
) { GM_DESTROY(m
); m
= 0; }
1077 if (h
) { GH_DESTROY(h
); h
= 0; }
1082 /* Check that all of the responses match up and XOR them together. */
1084 if (n
> BUFSZ
) die(1, "response too large");
1086 for (q
= qq
; q
; q
= q
->next
) {
1087 if (!q
->k
) die(1, "INTERNAL: query not complete");
1088 if (q
->sz
!= n
) die(1, "inconsistent response sizes");
1089 for (j
= 0; j
< n
; j
++) obuf
[j
] ^= q
->k
[j
];
1092 /* Write out the completed answer. */
1095 if ((nn
= write(STDOUT_FILENO
, p
, n
)) < 0)
1096 die(1, "error writing response: %s", strerror(errno
));
1102 /*----- Main program ------------------------------------------------------*/
1104 static void usage(FILE *fp
)
1106 pquis(fp
, "Usage: \n\
1107 $ [-OPTS] LABEL {ADDR:PORT | FILE} ...\n\
1108 $ [-OPTS] -l [ADDR:]PORT\n\
1112 static void version(FILE *fp
)
1113 { pquis(fp
, "$, version " VERSION
); }
1115 static void help(FILE *fp
)
1123 -d, --daemon Run in the background while listening.\n\
1124 -k, --keyring=FILE Read keys from FILE. [default = `keyring']\n\
1125 -l, --listen Listen for incoming requests and serve keys.\n\
1126 -p, --pidfile=FILE Write process id to FILE if in daemon mode.\n\
1127 -r, --random=FILE Key random number generator with contents of FILE.\n\
1131 int main(int argc
, char *argv
[])
1139 static const struct option opts
[] = {
1140 { "help", 0, 0, 'h' },
1141 { "version", 0, 0, 'v' },
1142 { "usage", 0, 0, 'u' },
1143 { "daemon", 0, 0, 'd' },
1144 { "keyfile", OPTF_ARGREQ
, 0, 'k' },
1145 { "listen", 0, 0, 'l' },
1146 { "pidfile", OPTF_ARGREQ
, 0, 'p' },
1147 { "random", OPTF_ARGREQ
, 0, 'r' },
1151 int i
= mdwopt(argc
, argv
, "hvu" "dk:lp:r:", opts
, 0, 0, 0);
1155 case 'h': help(stdout
); exit(0);
1156 case 'v': version(stdout
); exit(0);
1157 case 'u': usage(stdout
); exit(0);
1159 case 'd': flags
|= f_daemon
; break;
1160 case 'k': kfname
= optarg
; break;
1161 case 'l': flags
|= f_listen
; break;
1162 case 'p': pidfile
= optarg
; break;
1164 if (snarf(optarg
, &k
, &sz
))
1165 die(1, "failed to read `%s': %s", optarg
, strerror(errno
));
1166 rand_key(RAND_GLOBAL
, k
, sz
);
1169 default: flags
|= f_bogus
; break;
1173 argv
+= optind
; argc
-= optind
;
1174 if (flags
& f_listen
) argmin
= argmax
= 1;
1175 else argmin
= 2, argmax
= -1;
1176 if ((flags
& f_bogus
) || argc
< argmin
|| (argmax
>= 0 && argc
> argmax
))
1177 { usage(stderr
); exit(1); }
1179 fwatch_init(&kfwatch
, kfname
);
1180 kf
= CREATE(key_file
);
1181 if (key_open(kf
, kfname
, KOPEN_READ
, keymoan
, 0))
1182 die(1, "failed to open keyring file `%s'", kfname
);
1184 rand_noisesrc(RAND_GLOBAL
, &noise_source
);
1185 rand_seed(RAND_GLOBAL
, 512);
1187 if (flags
& f_listen
) return dolisten(argc
, argv
);
1188 else return doquery(argc
, argv
);
1191 /*----- That's all, folks -------------------------------------------------*/