struct query {
struct query *next;
+ const char *tag;
octet *k;
size_t sz;
struct server *s;
struct server *next;
struct sockaddr_in sin;
struct kinfo k;
+ const struct client_protocol *proto;
mp *u;
ge *U;
octet *h;
};
+struct client_protocol {
+ const char *name;
+ int (*setup)(struct query *, struct server *);
+ int (*receive)(struct query *, struct server *, buf *, buf *);
+ int (*retransmit)(struct query *, struct server *, buf *);
+};
+
/* Record a successful fetch of key material for a query Q. The data starts
* at K and is SZ bytes long. The data is copied: it's safe to overwrite it.
*/
-static void donequery(struct query *q, const void *k, size_t sz)
- { q->k = xmalloc(sz); memcpy(q->k, k, sz); q->sz = sz; nq--; }
+static int donequery(struct query *q, struct server *s,
+ const void *k, size_t sz)
+{
+ octet *tt;
+ ghash *h = 0;
+ int diffp;
+
+ /* If we have a hash, check that the fragment matches it. */
+ if (s && s->h) {
+ h = GH_INIT(s->k.hc);
+ GH_HASH(h, k, sz);
+ tt = GH_DONE(h, 0);
+ diffp = memcmp(tt, s->h, h->ops->c->hashsz);
+ GH_DESTROY(h);
+ if (diffp) {
+ moan("response from %s:%d doesn't match hash",
+ inet_ntoa(s->sin.sin_addr), ntohs(s->sin.sin_port));
+ return (-1);
+ }
+ }
+
+ /* Stash a copy of the key fragment for later. */
+ q->k = xmalloc(sz);
+ memcpy(q->k, k, sz);
+ q->sz = sz; nq--;
+
+ /* All good. */
+ return (0);
+}
+
+static int setup_v0(struct query *q, struct server *s)
+{
+ /* Choose an ephemeral private key u. Let x be our private key. We
+ * compute U = u P and transmit this.
+ */
+ s->u = mprand_range(MP_NEW, s->k.g->r, &rand_global, 0);
+ s->U = G_CREATE(s->k.g);
+ G_EXP(s->k.g, s->U, s->k.g->g, s->u);
+ D( debug_mp("u", s->u); debug_ge("U", s->k.g, s->U); )
+
+ return (0);
+}
+
+static int retransmit_v0(struct query *q, struct server *s, buf *bout)
+{
+ buf_putstrz(bout, q->tag);
+ G_TOBUF(s->k.g, bout, s->U);
+ return (0);
+}
+
+static int receive_v0(struct query *q, struct server *s, buf *bin, buf *bout)
+{
+ ge *R, *V = 0, *W = 0, *Y = 0, *Z = 0;
+ octet *kk, *t, *tt;
+ gcipher *c = 0;
+ gmac *m = 0;
+ ghash *h = 0;
+ size_t n, ksz;
+ octet *p;
+ int rc = -1;
+
+ R = G_CREATE(s->k.g);
+ V = G_CREATE(s->k.g); W = G_CREATE(s->k.g);
+ Y = G_CREATE(s->k.g); Z = G_CREATE(s->k.g);
+ if (G_FROMBUF(s->k.g, bin, V)) {
+ moan("invalid Diffie--Hellman vector from %s:%d",
+ inet_ntoa(s->sin.sin_addr), ntohs(s->sin.sin_port));
+ goto done;
+ }
+ if (G_FROMBUF(s->k.g, bin, W)) {
+ moan("invalid clue vector from %s:%d",
+ inet_ntoa(s->sin.sin_addr), ntohs(s->sin.sin_port));
+ goto done;
+ }
+ D( debug_ge("V", s->k.g, V); debug_ge("W", s->k.g, W); )
+
+ /* We have V and W from the server; determine Y = u V, R = W + Y and
+ * Z = x R, and then derive the symmetric keys.
+ */
+ G_EXP(s->k.g, Y, V, s->u);
+ G_MUL(s->k.g, R, W, Y);
+ G_EXP(s->k.g, Z, R, s->k.x);
+ D( debug_ge("R", s->k.g, R);
+ debug_ge("Y", s->k.g, Y);
+ debug_ge("Z", s->k.g, Z); )
+ derive(&s->k, R, Z, "cipher", s->k.cc->name, s->k.cc->keysz, &kk, &ksz);
+ c = GC_INIT(s->k.cc, kk, ksz);
+ derive(&s->k, R, Z, "mac", s->k.cc->name, s->k.cc->keysz, &kk, &ksz);
+ m = GM_KEY(s->k.mc, kk, ksz);
+
+ /* Find where the MAC tag is. */
+ if ((t = buf_get(bin, s->k.tagsz)) == 0) {
+ moan("missing tag from %s:%d",
+ inet_ntoa(s->sin.sin_addr), ntohs(s->sin.sin_port));
+ goto done;
+ }
+
+ /* Check the integrity of the ciphertext against the tag. */
+ p = BCUR(bin); n = BLEFT(bin);
+ h = GM_INIT(m);
+ GH_HASH(h, p, n);
+ tt = GH_DONE(h, 0);
+ if (!ct_memeq(t, tt, s->k.tagsz)) {
+ moan("incorrect tag from %s:%d",
+ inet_ntoa(s->sin.sin_addr), ntohs(s->sin.sin_port));
+ goto done;
+ }
+
+ /* Decrypt the result and declare this server done. */
+ GC_DECRYPT(c, p, p, n);
+ rc = donequery(q, s, p, n);
+
+done:
+ /* Clear up and go home. */
+ if (R) G_DESTROY(s->k.g, R);
+ if (V) G_DESTROY(s->k.g, V);
+ if (W) G_DESTROY(s->k.g, W);
+ if (Y) G_DESTROY(s->k.g, Y);
+ if (Z) G_DESTROY(s->k.g, Z);
+ if (c) GC_DESTROY(c);
+ if (m) GM_DESTROY(m);
+ if (h) GH_DESTROY(h);
+ return (rc);
+}
+
+static const struct client_protocol prototab[] = {
+ { "v0", setup_v0, receive_v0, retransmit_v0 },
+ { 0 }
+};
/* Initialize a query to a remote server. */
static struct query *qinit_net(const char *tag, const char *spec)
struct query *q;
struct server *s, **stail;
dstr d = DSTR_INIT, dd = DSTR_INIT;
+ const struct client_protocol *proto;
hex_ctx hc;
char *p, *pp, ch;
/* Allocate the query block. */
q = CREATE(struct query);
+ q->tag = tag;
stail = &q->s;
/* Put the spec somewhere we can hack at it. */
ch = *pp; *pp++ = 0;
s->sin.sin_port = htons(getport(p));
+ /* See if there's a protocol name. */
+ if (ch != '?')
+ p = "v0";
+ else {
+ p = pp;
+ pp += strcspn(pp, ";#=");
+ ch = *pp; *pp++ = 0;
+ }
+ for (proto = prototab; proto->name; proto++)
+ if (strcmp(proto->name, p) == 0) goto found_proto;
+ die(1, "unknown protocol name `%s'", p);
+ found_proto:
+ s->proto = proto;
+
/* If there's a key tag then extract that; otherwise use a default. */
if (ch != '=')
p = "udpkey-kem";
if (loadkey(p, &s->k, 1)) exit(1);
D( debug_mp("x", s->k.x); debug_ge("X", s->k.g, s->k.X); )
- /* Choose an ephemeral private key u. Let x be our private key. We
- * compute U = u P and transmit this.
- */
- s->u = mprand_range(MP_NEW, s->k.g->r, &rand_global, 0);
- s->U = G_CREATE(s->k.g);
- G_EXP(s->k.g, s->U, s->k.g->g, s->u);
- D( debug_mp("u", s->u); debug_ge("U", s->k.g, s->U); )
-
/* Link the server on. */
*stail = s; stail = &s->next;
ch = *pp++;
}
+ /* Initialize the protocol. */
+ if (s->proto->setup(q, s)) die(1, "failed to initialize protocol");
+
/* If there are more servers, then continue parsing. */
if (!ch) break;
else if (ch != ';') die(1, "invalid syntax: expected `;'");
if (snarf(file, &k, &sz))
die(1, "failed to read `%s': %s", file, strerror(errno));
q->s = 0;
- donequery(q, k, sz);
+ donequery(q, 0, k, sz);
return (q);
}
fd_set fdin;
struct timeval now, when, tv;
struct sockaddr_in sin;
- ge *R, *V = 0, *W = 0, *Y = 0, *Z = 0;
- octet *kk, *t, *tt;
- gcipher *c = 0;
- gmac *m = 0;
- ghash *h = 0;
socklen_t len;
unsigned next = 0;
buf bin, bout;
- size_t n, j, ksz;
+ size_t n, j;
ssize_t nn;
/* Create a socket. We just use the one socket for everything. We don't
if (q->k) continue;
for (s = q->s; s; s = s->next) {
buf_init(&bout, obuf, sizeof(obuf));
- buf_putstrz(&bout, tag);
- G_TOBUF(s->k.g, &bout, s->U);
+ if (s->proto->retransmit(q, s, &bout)) continue;
if (BBAD(&bout)) {
moan("overflow while constructing request!");
continue;
else if (errno == EINTR) continue;
else {
moan("error receiving reply: %s", strerror(errno));
- goto again;
+ continue;
}
}
}
moan("received reply from unexpected source %s:%d",
inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
+ continue;
found:
/* If the query we found has now been satisfied, ignore this packet.
*/
- if (q->k) goto again;
-
- /* Start parsing the reply. */
- buf_init(&bin, ibuf, nn);
- R = G_CREATE(s->k.g);
- V = G_CREATE(s->k.g); W = G_CREATE(s->k.g);
- Y = G_CREATE(s->k.g); Z = G_CREATE(s->k.g);
- if (G_FROMBUF(s->k.g, &bin, V)) {
- moan("invalid Diffie--Hellman vector from %s:%d",
- inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
- }
- if (G_FROMBUF(s->k.g, &bin, W)) {
- moan("invalid clue vector from %s:%d",
- inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
- }
- D( debug_ge("V", s->k.g, V); debug_ge("W", s->k.g, W); )
+ if (q->k) continue;
- /* We have V and W from the server; determine Y = u V, R = W + Y and
- * Z = x R, and then derive the symmetric keys.
+ /* Parse the reply, and either finish the job or get a message to
+ * send back to the server.
*/
- G_EXP(s->k.g, Y, V, s->u);
- G_MUL(s->k.g, R, W, Y);
- G_EXP(s->k.g, Z, R, s->k.x);
- D( debug_ge("R", s->k.g, R);
- debug_ge("Y", s->k.g, Y);
- debug_ge("Z", s->k.g, Z); )
- derive(&s->k, R, Z, "cipher", s->k.cc->name, s->k.cc->keysz,
- &kk, &ksz);
- c = GC_INIT(s->k.cc, kk, ksz);
- derive(&s->k, R, Z, "mac", s->k.cc->name, s->k.cc->keysz,
- &kk, &ksz);
- m = GM_KEY(s->k.mc, kk, ksz);
-
- /* Find where the MAC tag is. */
- if ((t = buf_get(&bin, s->k.tagsz)) == 0) {
- moan("missing tag from %s:%d",
- inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
- }
-
- /* Check the integrity of the ciphertext against the tag. */
- p = BCUR(&bin); n = BLEFT(&bin);
- h = GM_INIT(m);
- GH_HASH(h, p, n);
- tt = GH_DONE(h, 0);
- if (!ct_memeq(t, tt, s->k.tagsz)) {
- moan("incorrect tag from %s:%d",
- inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
- }
-
- /* Decrypt the result and declare this server done. */
- GC_DECRYPT(c, p, p, n);
- if (s->h) {
- GH_DESTROY(h);
- h = GH_INIT(s->k.hc);
- GH_HASH(h, p, n);
- tt = GH_DONE(h, 0);
- if (memcmp(tt, s->h, h->ops->c->hashsz) != 0) {
- moan("response from %s:%d doesn't match hash",
- inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
- goto again;
- }
+ buf_init(&bin, ibuf, nn);
+ buf_init(&bout, obuf, sizeof(obuf));
+ if (s->proto->receive(q, s, &bin, &bout)) continue;
+ if (q->k) continue;
+ if (!BLEN(&bout) && s->proto->retransmit(q, s, &bout)) continue;
+ if (BBAD(&bout)) {
+ moan("overflow while constructing request!");
+ continue;
}
- donequery(q, p, n);
-
- again:
- /* Tidy things up for the next run through. */
- if (R) { G_DESTROY(s->k.g, R); R = 0; }
- if (V) { G_DESTROY(s->k.g, V); V = 0; }
- if (W) { G_DESTROY(s->k.g, W); W = 0; }
- if (Y) { G_DESTROY(s->k.g, Y); Y = 0; }
- if (Z) { G_DESTROY(s->k.g, Z); Z = 0; }
- if (c) { GC_DESTROY(c); c = 0; }
- if (m) { GM_DESTROY(m); m = 0; }
- if (h) { GH_DESTROY(h); h = 0; }
+ sendto(sk, BBASE(&bout), BLEN(&bout), 0,
+ (struct sockaddr *)&s->sin, sizeof(s->sin));
}
}
}
~mdw / udpkey / blobdiff