*
* This file is part of Trivial IP Encryption (TrIPE).
*
- * TrIPE is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * TrIPE is free software: you can redistribute it and/or modify it under
+ * the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your
+ * option) any later version.
*
- * TrIPE is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * TrIPE is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
*
* You should have received a copy of the GNU General Public License
- * along with TrIPE; if not, write to the Free Software Foundation,
- * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
*/
/*----- Header files ------------------------------------------------------*/
*
* %$\cookie{kx-switch-ok}, E_K(u_A))$%
* Switch received. Committed; send data; move to @KXS_SWITCH@.
+ *
+ * %$\cookie{kx-token-request}, u, E_L(n)$%
+ * %$L = H(u, u^\alpha)$%, and %$n$% is a string of the form
+ * `[PEER.]KEYTAG'. Expect %$\cookie{kx-token}$% by return.
+ *
+ * %$\cookie{kx-token}, v, E_{L'}(t)$%
+ * %$L' = H(v, v^\alpha)$%, and %$t$% is a token associated with %$n$%
+ * (see %$\cookie{kx-token-request}$% above).
+ *
+ * %$\cookie{kx-knock}, u, E_L(n, t), r_A$%
+ * %$L$%, %$n$% and %$t$% are as %$\cookie{kx-token}$% and
+ * %$\cookie{kx-token-request}$%; %$r_A$% is as in
+ * %$\cookie{kx-pre-challenge}$%. If the token %$t$% doesn't match
+ * %$n$%, then warn and discard. If a peer named PEER (or KEYTAG)
+ * exists then proceed as for %$\cookie{kx-pre-challenge}$%. Otherwise
+ * issue a notification `NOTE KNOCK PEER ADDR...' and discard.
*/
/*----- Static tables -----------------------------------------------------*/
static const char *const pkname[] = {
- "pre-challenge", "challenge", "reply", "switch-rq", "switch-ok"
+ "pre-challenge", "challenge", "reply", "switch-rq", "switch-ok",
+ "token-rq", "token", "knock"
};
/*----- Various utilities -------------------------------------------------*/
/* --- @hashge@ --- *
*
* Arguments: @ghash *h@ = pointer to hash context
- * @ge *x@ = pointer to group element
+ * @const dhgrp *g@ = pointer to group
+ * @const dhge *Y@ = pointer to group element
*
* Returns: ---
*
* @buf_t@.
*/
-static void hashge(ghash *h, ge *x)
+static void hashge(ghash *h, const dhgrp *g, const dhge *Y)
{
buf b;
+
buf_init(&b, buf_t, sizeof(buf_t));
- G_TOBUF(gg, &b, x);
+ g->ops->stge(g, &b, Y, DHFMT_HASH);
assert(BOK(&b));
GH_HASH(h, BBASE(&b), BLEN(&b));
}
/* --- @mpmask@ --- *
*
* Arguments: @buf *b@ = output buffer
- * @mp *x@ = the plaintext integer
+ * @const dhgrp *g@ = the group
+ * @const dhsc *x@ = the plaintext scalar
* @size_t n@ = the expected size of the plaintext
+ * @gcipher *mgfc@ = mask-generating function to use
* @const octet *k@ = pointer to key material
* @size_t ksz@ = size of the key
*
- * Returns: Pointer to the output.
+ * Returns: ---
*
- * Use: Masks a multiprecision integer: returns %$x \xor H(k)$%, so
- * it's a random oracle thing rather than an encryption thing.
+ * Use: Masks a scalar: returns %$x \xor H(k)$%, so it's a random
+ * oracle thing rather than an encryption thing. Breaks the
+ * output buffer on error.
*/
-static octet *mpmask(buf *b, mp *x, size_t n, const octet *k, size_t ksz)
+static void mpmask(buf *b, const dhgrp *g, const dhsc *x, size_t n,
+ const gccipher *mgfc, const octet *k, size_t ksz)
{
gcipher *mgf;
octet *p;
- if ((p = buf_get(b, n)) == 0)
- return (0);
- mgf = GC_INIT(algs.mgf, k, ksz);
+ if ((p = buf_get(b, n)) == 0) return;
+ mgf = GC_INIT(mgfc, k, ksz);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "masking index = %s", mpstr(x));
- trace_block(T_CRYPTO, "masking key", k, ksz);
+ trace(T_CRYPTO, "crypto: masking scalar = %s", g->ops->scstr(g, x));
+ trace_block(T_CRYPTO, "crypto: masking key", k, ksz);
}))
- mp_storeb(x, buf_t, n);
+ if (g->ops->stsc(g, buf_t, n, x)) { buf_break(b); return; }
GC_ENCRYPT(mgf, buf_t, p, n);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace_block(T_CRYPTO, "index plaintext", buf_t, n);
- trace_block(T_CRYPTO, "masked ciphertext", p, n);
+ trace_block(T_CRYPTO, "crypto: scalar plaintext", buf_t, n);
+ trace_block(T_CRYPTO, "crypto: masked ciphertext", p, n);
}))
GC_DESTROY(mgf);
- return (p);
}
/* --- @mpunmask@ --- *
*
- * Arguments: @mp *d@ = the output integer
+ * Arguments: @const dhgrp *g@ = the group
* @const octet *p@ = pointer to the ciphertext
* @size_t n@ = the size of the ciphertext
+ * @gcipher *mgfc@ = mask-generating function to use
* @const octet *k@ = pointer to key material
* @size_t ksz@ = size of the key
*
- * Returns: The decrypted integer, or null.
+ * Returns: The decrypted scalar, or null.
*
- * Use: Unmasks a multiprecision integer.
+ * Use: Unmasks a scalar.
*/
-static mp *mpunmask(mp *d, const octet *p, size_t n,
- const octet *k, size_t ksz)
+static dhsc *mpunmask(const dhgrp *g, const octet *p, size_t n,
+ const gccipher *mgfc, const octet *k, size_t ksz)
{
gcipher *mgf;
+ dhsc *x;
- mgf = GC_INIT(algs.mgf, k, ksz);
+ mgf = GC_INIT(mgfc, k, ksz);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace_block(T_CRYPTO, "unmasking key", k, ksz);
- trace_block(T_CRYPTO, "masked ciphertext", p, n);
+ trace_block(T_CRYPTO, "crypto: unmasking key", k, ksz);
+ trace_block(T_CRYPTO, "crypto: masked ciphertext", p, n);
}))
GC_DECRYPT(mgf, p, buf_t, n);
- d = mp_loadb(d, buf_t, n);
+ x = g->ops->ldsc(g, buf_t, n);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace_block(T_CRYPTO, "index plaintext", buf_t, n);
- trace(T_CRYPTO, "unmasked index = %s", mpstr(d));
+ trace_block(T_CRYPTO, "crypto: scalar plaintext", buf_t, n);
+ trace(T_CRYPTO, "crypto: unmasked scalar = %s",
+ x ? g->ops->scstr(g, x) : "<failed>");
}))
GC_DESTROY(mgf);
- return (d);
+ return (x);
}
/* --- @hashcheck@ --- *
*
- * Arguments: @ge *kpub@ = sender's public key
- * @ge *cc@ = receiver's challenge
- * @ge *c@ = sender's challenge
- * @ge *y@ = reply to sender's challenge
+ * Arguments: @keyexch *kx@ = pointer to key-exchange block
+ * @const dhge *K@ = sender's public key
+ * @const dhge *CC@ = receiver's challenge
+ * @const dhge *C@ = sender's challenge
+ * @const dhge *Y@ = reply to sender's challenge
*
* Returns: Pointer to the hash value (in @buf_t@)
*
* indices to prove the validity of challenges. This computes
* the masking key used in challenge check values. This is
* really the heart of the whole thing, since it ensures that
- * the index can be recovered from the history of hashing
+ * the scalar can be recovered from the history of hashing
* queries, which gives us (a) a proof that the authentication
* process is zero-knowledge, and (b) a proof that the whole
* key-exchange is deniable.
*/
-static const octet *hashcheck(ge *kpub, ge *cc, ge *c, ge *y)
+static const octet *hashcheck(keyexch *kx, const dhge *K,
+ const dhge *CC, const dhge *C, const dhge *Y)
{
- ghash *h = GH_INIT(algs.h);
+ ghash *h = GH_INIT(kx->kpriv->algs.h);
+ const dhgrp *g = kx->kpriv->grp;
HASH_STRING(h, "tripe-expected-reply");
- hashge(h, kpub);
- hashge(h, cc);
- hashge(h, c);
- hashge(h, y);
+ hashge(h, g, K);
+ hashge(h, g, CC);
+ hashge(h, g, C);
+ hashge(h, g, Y);
GH_DONE(h, buf_t);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "computing challenge check hash");
- trace(T_CRYPTO, "public key = %s", gestr(gg, kpub));
- trace(T_CRYPTO, "receiver challenge = %s", gestr(gg, cc));
- trace(T_CRYPTO, "sender challenge = %s", gestr(gg, c));
- trace(T_CRYPTO, "sender reply = %s", gestr(gg, y));
- trace_block(T_CRYPTO, "hash output", buf_t, algs.hashsz);
+ trace(T_CRYPTO, "crypto: computing challenge check hash");
+ trace(T_CRYPTO, "crypto: public key = %s", g->ops->gestr(g, K));
+ trace(T_CRYPTO, "crypto: receiver challenge = %s", g->ops->gestr(g, CC));
+ trace(T_CRYPTO, "crypto: sender challenge = %s", g->ops->gestr(g, C));
+ trace(T_CRYPTO, "crypto: sender reply = %s", g->ops->gestr(g, Y));
+ trace_block(T_CRYPTO, "crypto: hash output", buf_t, kx->kpriv->algs.hashsz);
}))
GH_DESTROY(h);
return (buf_t);
*
* Arguments: @keyexch *kx@ = pointer to key exchange block
* @buf *b@ = output buffer for challenge
- * @ge *c@ = peer's actual challenge
+ * @const dhge *C@ = peer's actual challenge
* @const octet *hc@ = peer's challenge cookie
*
* Returns: ---
* Use: Writes a full challenge to the message buffer.
*/
-static void sendchallenge(keyexch *kx, buf *b, ge *c, const octet *hc)
+static void sendchallenge(keyexch *kx, buf *b,
+ const dhge *C, const octet *hc)
{
- G_TOBUF(gg, b, kx->c);
- buf_put(b, hc, algs.hashsz);
- mpmask(b, kx->alpha, indexsz,
- hashcheck(kpub, c, kx->c, kx->rx), algs.hashsz);
+ const dhgrp *g = kx->kpriv->grp;
+ g->ops->stge(g, b, kx->C, DHFMT_VAR);
+ buf_put(b, hc, kx->kpriv->algs.hashsz);
+ mpmask(b, g, kx->a, g->scsz, kx->kpriv->algs.mgf,
+ hashcheck(kx, kx->kpriv->K, C, kx->C, kx->RX),
+ kx->kpriv->algs.hashsz);
}
/* --- @timer@ --- *
kx->f |= KXF_TIMER;
}
+/* --- @f2tv@ --- *
+ *
+ * Arguments: @struct timeval *tv@ = where to write the timeval
+ * @double t@ = a time as a floating point number
+ *
+ * Returns: ---
+ *
+ * Use: Converts a floating-point time into a timeval.
+ */
+
+static void f2tv(struct timeval *tv, double t)
+{
+ tv->tv_sec = t;
+ tv->tv_usec = (t - tv->tv_sec)*MILLION;
+}
+
+/* --- @wobble@ --- *
+ *
+ * Arguments: @double t@ = a time interval
+ *
+ * Returns: The same time interval, with a random error applied.
+ */
+
+static double wobble(double t)
+{
+ uint32 r = rand_global.ops->word(&rand_global);
+ double w = (r/F_2P32) - 0.5;
+ return (t + t*w*T_WOBBLE);
+}
+
+/* --- @rs_time@ --- *
+ *
+ * Arguments: @retry *rs@ = current retry state
+ * @struct timeval *tv@ = where to write the result
+ * @const struct timeval *now@ = current time, or null
+ *
+ * Returns: ---
+ *
+ * Use: Computes a time at which to retry sending a key-exchange
+ * packet. This algorithm is subject to change, but it's
+ * currently a capped exponential backoff, slightly randomized
+ * to try to keep clients from hammering a server that's only
+ * just woken up.
+ *
+ * If @now@ is null then the function works out the time for
+ * itself.
+ */
+
+static void rs_time(retry *rs, struct timeval *tv, const struct timeval *now)
+{
+ double t;
+ struct timeval rtv;
+
+ if (!rs->t)
+ t = SEC(2);
+ else {
+ t = (rs->t * 5)/4;
+ if (t > MIN(5)) t = MIN(5);
+ }
+ rs->t = t;
+
+ if (!now) {
+ now = tv;
+ gettimeofday(tv, 0);
+ }
+ f2tv(&rtv, wobble(t));
+ TV_ADD(tv, now, &rtv);
+}
+
+/* --- @retry_reset@ --- *
+ *
+ * Arguments: @retry *rs@ = retry state
+ *
+ * Returns: --
+ *
+ * Use: Resets a retry state to indicate that progress has been
+ * made. Also useful for initializing the state in the first
+ * place.
+ */
+
+static void rs_reset(retry *rs) { rs->t = 0; }
+
+/* --- @notice_message@ --- *
+ *
+ * Arguments: @keyexch *kx@ = pointer to key-exchange block
+ *
+ * Returns: Zero if OK; @-1@ if the public key is in a bad state.
+ *
+ * Use: Updates the key-exchange state following a received message.
+ * Specifically, if there's no currently active key-exchange in
+ * progress, and we're not in the cooling-off period, then
+ * commence a new one; reset the retry timers; and if we're
+ * corked then pop the cork so that we can reply.
+ */
+
+static int checkpub(keyexch *kx);
+static void stop(keyexch *kx);
+static void start(keyexch *kx, time_t now);
+
+static int notice_message(keyexch *kx)
+{
+ struct timeval now, tv;
+
+ gettimeofday(&now, 0);
+ rs_reset(&kx->rs);
+ if (kx->f & KXF_CORK) {
+ start(kx, now.tv_sec);
+ rs_time(&kx->rs, &tv, &now);
+ settimer(kx, &tv);
+ a_notify("KXSTART", "?PEER", kx->p, A_END);
+ }
+ if (checkpub(kx)) return (-1);
+ if (!VALIDP(kx, now.tv_sec)) {
+ stop(kx);
+ start(kx, now.tv_sec);
+ }
+ return (0);
+}
+
+/* --- @update_stats_tx@, @update_stats_rx@ --- *
+ *
+ * Arguments: @keyexch *kx@ = pointer to key-exchange block
+ * @int ok@ = nonzero if the message was valid (for @rx@)
+ * @size_t sz@ = size of sent message
+ *
+ * Returns: ---
+ *
+ * Use: Records that a key-exchange message was sent to, or received
+ * from, the peer.
+ */
+
+static void update_stats_tx(keyexch *kx, size_t sz)
+ { stats *st = p_stats(kx->p); st->n_kxout++; st->sz_kxout += sz; }
+
+static void update_stats_rx(keyexch *kx, int ok, size_t sz)
+{
+ stats *st = p_stats(kx->p);
+
+ if (!ok) st->n_reject++;
+ else { st->n_kxin++; st->sz_kxin += sz; }
+}
+
/*----- Challenge management ----------------------------------------------*/
/* --- Notes on challenge management --- *
static void kxc_destroy(kxchal *kxc)
{
+ const dhgrp *g = kxc->kx->kpriv->grp;
if (kxc->f & KXF_TIMER)
sel_rmtimer(&kxc->t);
- G_DESTROY(gg, kxc->c);
- G_DESTROY(gg, kxc->r);
+ g->ops->freege(g, kxc->C);
+ g->ops->freege(g, kxc->R);
ks_drop(kxc->ks);
DESTROY(kxc);
}
* Returns: A pointer to the challenge block.
*
* Use: Returns a pointer to a new challenge block to fill in.
+ * In particular, the @c@ and @r@ members are left
+ * uninitialized.
*/
static kxchal *kxc_new(keyexch *kx)
/* --- Fill in the new structure --- */
kxc = CREATE(kxchal);
- kxc->c = G_CREATE(gg);
- kxc->r = G_CREATE(gg);
kxc->ks = 0;
kxc->kx = kx;
kxc->f = 0;
kx->r[i] = kxc;
+ rs_reset(&kxc->rs);
return (kxc);
}
/* --- @kxc_bychal@ --- *
*
* Arguments: @keyexch *kx@ = pointer to key exchange block
- * @ge *c@ = challenge from remote host
+ * @const dhge *C@ = challenge from remote host
*
* Returns: Pointer to the challenge block, or null.
*
* Use: Finds a challenge block, given its challenge.
*/
-static kxchal *kxc_bychal(keyexch *kx, ge *c)
+static kxchal *kxc_bychal(keyexch *kx, const dhge *C)
{
+ const dhgrp *g = kx->kpriv->grp;
unsigned i;
for (i = 0; i < kx->nr; i++) {
- if (G_EQ(gg, c, kx->r[i]->c))
+ if (g->ops->eq(g, C, kx->r[i]->C))
return (kx->r[i]);
}
return (0);
unsigned i;
for (i = 0; i < kx->nr; i++) {
- if (memcmp(hc, kx->r[i]->hc, algs.hashsz) == 0)
+ if (memcmp(hc, kx->r[i]->hc, kx->kpriv->algs.hashsz) == 0)
return (kx->r[i]);
}
return (0);
static void kxc_answer(keyexch *kx, kxchal *kxc)
{
- stats *st = p_stats(kx->p);
buf *b = p_txstart(kx->p, MSG_KEYEXCH | KX_REPLY);
+ const dhgrp *g = kx->kpriv->grp;
struct timeval tv;
buf bb;
/* --- Build the reply packet --- */
T( trace(T_KEYEXCH, "keyexch: sending reply to `%s'", p_name(kx->p)); )
- sendchallenge(kx, b, kxc->c, kxc->hc);
+ sendchallenge(kx, b, kxc->C, kxc->hc);
buf_init(&bb, buf_i, sizeof(buf_i));
- G_TORAW(gg, &bb, kxc->r);
+ g->ops->stge(g, &bb, kxc->R, DHFMT_STD);
buf_flip(&bb);
ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_REPLY, &bb, b);
/* --- Update the statistics --- */
if (BOK(b)) {
- st->n_kxout++;
- st->sz_kxout += BLEN(b);
+ update_stats_tx(kx, BLEN(b));
p_txend(kx->p);
}
if (kxc->f & KXF_TIMER)
sel_rmtimer(&kxc->t);
gettimeofday(&tv, 0);
- tv.tv_sec += T_RETRY;
+ rs_time(&kxc->rs, &tv, &tv);
sel_addtimer(&sel, &kxc->t, &tv, kxc_timer, kxc);
kxc->f |= KXF_TIMER;
}
/*----- Individual message handlers ---------------------------------------*/
+static ratelim unauth_limit;
+
+/* --- @dotokenrq@ --- *
+ *
+ * Arguments: @const addr *a@ = sender's address
+ * @buf *b@ = buffer containing the packet
+ *
+ * Returns: ---
+ *
+ * Use: Processes a token-request message.
+ */
+
+static void dotokenrq(const addr *a, buf *b)
+{
+ uint32 id;
+ kdata *kpriv = 0, *kpub = 0;
+ char *pname;
+ const char *tag;
+ size_t sz;
+ buf bb, bbb;
+
+ /* --- Check if we're in danger of overloading --- */
+
+ if (ratelim_withdraw(&unauth_limit, 1)) goto done;
+
+ /* --- Start building the reply --- */
+
+ buf_init(&bbb, buf_o, sizeof(buf_o));
+ buf_putu8(&bbb, MSG_KEYEXCH | KX_TOKEN);
+
+ /* --- Fetch and copy the challenge string --- */
+
+ if (buf_getbuf16(b, &bb)) goto done;
+ buf_putmem16(&bbb, BBASE(&bb), BSZ(&bb));
+
+ /* --- Make our own challenge for the response --- */
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ c_new(0, 0, &bb); assert(BOK(&bb)); buf_putbuf16(&bbb, &bb);
+
+ /* --- Figure out which private key I'm supposed to use --- */
+
+ if (buf_getu32(b, &id)) goto done;
+ if ((kpriv = km_findprivbyid(id)) == 0) goto done;
+
+ /* --- Decrypt the message --- */
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ if (ies_decrypt(kpriv, MSG_KEYEXCH | KX_TOKENRQ, b, &bb) || BLEFT(b))
+ goto done;
+
+ /* --- Parse the token request and find the sender's public key --- */
+
+ assert(BOK(&bb)); buf_flip(&bb);
+ if ((pname = buf_getmem16(&bb, &sz)) == 0 || memchr(pname, 0, sz))
+ goto done;
+ assert(sz < sizeof(buf_t) - ((const octet *)pname - buf_t));
+ pname[sz] = 0;
+ if ((tag = strchr(pname, '.')) != 0) tag++;
+ else tag = pname;
+ if ((kpub = km_findpub(tag)) == 0) goto done;
+
+ /* --- Build and encrypt the token --- */
+
+ buf_init(&bb, buf_i, sizeof(buf_i));
+ c_new(pname, sz, &bb);
+ assert(BOK(&bb)); buf_flip(&bb);
+ if (ies_encrypt(kpub, MSG_KEYEXCH | KX_TOKEN, &bb, &bbb)) goto done;
+ assert(BOK(&bbb));
+
+ /* --- Send the response -- or at least give it a try --- */
+
+ p_txaddr(a, BBASE(&bbb), BLEN(&bbb));
+
+ /* --- All done --- */
+
+done:
+ if (kpriv) km_unref(kpriv);
+ if (kpub) km_unref(kpub);
+}
+
+/* --- @dotoken@ --- *
+ *
+ * Arguments: @keyexch *kx@ = pointer to key exchange block
+ * @buf *b@ = buffer containing the packet
+ *
+ * Returns: Zero if OK, nonzero of the packet was rejected.
+ *
+ * Use: Processes a token message.
+ */
+
+static int dotoken(keyexch *kx, buf *b)
+{
+ buf bb;
+ buf *bbb;
+ const dhgrp *g = kx->kpriv->grp;
+ octet *p;
+ size_t sz;
+
+ /* --- Make sure this is a sensible message to have received --- */
+
+ if (!kx->p->spec.knock) return (-1);
+
+ /* --- First, collect and verify our challenge --- */
+
+ if (buf_getbuf16(b, &bb) || c_check(0, 0, &bb) || BLEFT(&bb)) return (-1);
+
+ /* --- Start building the knock message from here --- */
+
+ bbb = p_txstart(kx->p, MSG_KEYEXCH | KX_KNOCK);
+
+ /* --- Copy the peer's challenge --- */
+
+ if (buf_getbuf16(b, &bb)) return (-1);
+ buf_putmem16(bbb, BBASE(&bb), BSZ(&bb));
+
+ /* --- Add the key indicator --- */
+
+ buf_putu32(bbb, kx->kpub->id);
+
+ /* --- Building the knock payload --- */
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ buf_putstr16(&bb, kx->p->spec.knock);
+ sz = BLEN(&bb)%64; if (sz) sz = 64 - sz;
+ if (ies_decrypt(kx->kpriv, MSG_KEYEXCH | KX_TOKEN, b, &bb)) return (-1);
+ p = buf_get(&bb, sz); assert(p); memset(p, 0, sz);
+ assert(BOK(&bb)); buf_flip(&bb);
+ if (ies_encrypt(kx->kpub, MSG_KEYEXCH | KX_KNOCK, &bb, bbb)) return (-1);
+
+ /* --- Finally, the pre-challenge group element --- */
+
+ g->ops->stge(g, bbb, kx->C, DHFMT_VAR);
+
+ /* --- And we're done --- */
+
+ if (BBAD(bbb)) return (-1);
+ update_stats_tx(kx, BLEN(bbb));
+ p_txend(kx->p);
+ return (0);
+}
+
/* --- @doprechallenge@ --- *
*
* Arguments: @keyexch *kx@ = pointer to key exchange block
static int doprechallenge(keyexch *kx, buf *b)
{
- stats *st = p_stats(kx->p);
- ge *c = G_CREATE(gg);
+ const dhgrp *g = kx->kpriv->grp;
+ dhge *C = 0;
ghash *h;
/* --- Ensure that we're in a sensible state --- */
/* --- Unpack the packet --- */
- if (G_FROMBUF(gg, b, c) || BLEFT(b))
+ if ((C = g->ops->ldge(g, b, DHFMT_VAR)) == 0 || BLEFT(b))
goto bad;
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: challenge = %s", gestr(gg, c));
+ trace(T_CRYPTO, "crypto: challenge = %s", g->ops->gestr(g, C));
}))
/* --- Send out a full challenge by return --- */
b = p_txstart(kx->p, MSG_KEYEXCH | KX_CHAL);
- h = GH_INIT(algs.h);
+ h = GH_INIT(kx->kpriv->algs.h);
HASH_STRING(h, "tripe-cookie");
- hashge(h, c);
- sendchallenge(kx, b, c, GH_DONE(h, 0));
+ hashge(h, g, C);
+ sendchallenge(kx, b, C, GH_DONE(h, 0));
GH_DESTROY(h);
- st->n_kxout++;
- st->sz_kxout += BLEN(b);
+ update_stats_tx(kx, BLEN(b));
p_txend(kx->p);
/* --- Done --- */
- G_DESTROY(gg, c);
+ g->ops->freege(g, C);
return (0);
bad:
- if (c) G_DESTROY(gg, c);
+ if (C) g->ops->freege(g, C);
return (-1);
}
+/* --- @doknock@ --- *
+ *
+ * Arguments: @const addr *a@ = sender's address
+ * @buf *b@ = buffer containing the packet
+ *
+ * Returns: ---
+ *
+ * Use: Processes a knock message.
+ */
+
+static void doknock(const addr *a, buf *b)
+{
+ keyexch *kx;
+ peer *p;
+ uint32 id;
+ kdata *kpriv = 0;
+ char *pname;
+ size_t sz, msgsz = BLEN(b);
+ buf bb;
+ int rc;
+
+ /* --- Read and check the challenge --- */
+
+ buf_getbuf16(b, &bb);
+ if (c_check(0, 0, &bb)) goto done;
+
+ /* --- Figure out which private key I'm supposed to use --- */
+
+ if (buf_getu32(b, &id)) goto done;
+ if ((kpriv = km_findprivbyid(id)) == 0) goto done;
+
+ /* --- Decrypt and check the peer's name against the token --- */
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ if (ies_decrypt(kpriv, MSG_KEYEXCH | KX_KNOCK, b, &bb)) goto done;
+ assert(BOK(&bb)); buf_flip(&bb);
+ if ((pname = buf_getmem16(&bb, &sz)) == 0 ||
+ memchr(pname, 0, sz) ||
+ c_check(pname, sz, &bb))
+ goto done;
+ assert(sz < sizeof(buf_t) - ((const octet *)pname - buf_t));
+ pname[sz] = 0;
+
+ /* --- If we can't find the peer, then issue a notification --- */
+
+ if ((p = p_find(pname)) == 0) {
+ a_notify("KNOCK", "%s", pname, "?ADDR", a, A_END);
+ goto done;
+ }
+
+ /* --- Update the peer's address --- */
+
+ kx = &p->kx;
+ p_updateaddr(kx->p, a);
+
+ /* --- Now treat the remainder of the message as a pre-challenge --- */
+
+ notice_message(kx);
+ rc = doprechallenge(kx, b);
+ update_stats_rx(kx, !rc, msgsz);
+
+ /* --- All done: clean up --- */
+
+done:
+ if (kpriv) km_unref(kpriv);
+}
+
/* --- @respond@ --- *
*
* Arguments: @keyexch *kx@ = pointer to key exchange block
static kxchal *respond(keyexch *kx, unsigned msg, buf *b)
{
- ge *c = G_CREATE(gg);
- ge *r = G_CREATE(gg);
- ge *cc = G_CREATE(gg);
+ const dhgrp *g = kx->kpriv->grp;
+ const algswitch *algs = &kx->kpriv->algs;
+ size_t ixsz = g->scsz;
+ dhge *C = 0;
+ dhge *R = 0;
+ dhge *CC = 0;
+ deriveargs a;
const octet *hc, *ck;
- size_t x, y, z;
- mp *cv = 0;
+ dhsc *c = 0;
kxchal *kxc;
ghash *h = 0;
buf bb;
/* --- Unpack the packet --- */
- if (G_FROMBUF(gg, b, c) ||
- (hc = buf_get(b, algs.hashsz)) == 0 ||
- (ck = buf_get(b, indexsz)) == 0) {
+ if ((C = g->ops->ldge(g, b, DHFMT_VAR)) == 0 ||
+ (hc = buf_get(b, algs->hashsz)) == 0 ||
+ (ck = buf_get(b, ixsz)) == 0) {
a_warn("KX", "?PEER", kx->p, "invalid", "%s", pkname[msg], A_END);
goto bad;
}
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: challenge = %s", gestr(gg, c));
- trace_block(T_CRYPTO, "crypto: cookie", hc, algs.hashsz);
- trace_block(T_CRYPTO, "crypto: check-value", ck, indexsz);
+ trace(T_CRYPTO, "crypto: challenge = %s", g->ops->gestr(g, C));
+ trace_block(T_CRYPTO, "crypto: cookie", hc, algs->hashsz);
+ trace_block(T_CRYPTO, "crypto: check-value", ck, ixsz);
}))
/* --- Discard a packet with an invalid cookie --- */
- if (hc && memcmp(hc, kx->hc, algs.hashsz) != 0) {
+ if (hc && memcmp(hc, kx->hc, algs->hashsz) != 0) {
a_warn("KX", "?PEER", kx->p, "incorrect", "cookie", A_END);
goto bad;
}
* This will also find a challenge block and, if necessary, populate it.
*/
- if ((kxc = kxc_bychal(kx, c)) != 0) {
- h = GH_INIT(algs.h);
+ if ((kxc = kxc_bychal(kx, C)) != 0) {
+ h = GH_INIT(algs->h);
HASH_STRING(h, "tripe-check-hash");
- GH_HASH(h, ck, indexsz);
- ok = !memcmp(kxc->ck, GH_DONE(h, 0), algs.hashsz);
+ GH_HASH(h, ck, ixsz);
+ ok = !memcmp(kxc->ck, GH_DONE(h, 0), algs->hashsz);
GH_DESTROY(h);
if (!ok) goto badcheck;
} else {
/* --- Compute the reply, and check the magic --- */
- G_EXP(gg, r, c, kpriv);
- cv = mpunmask(MP_NEW, ck, indexsz,
- hashcheck(kx->kpub, kx->c, c, r), algs.hashsz);
+ R = g->ops->mul(g, kx->kpriv->k, C);
+ if ((c = mpunmask(g, ck, ixsz, algs->mgf,
+ hashcheck(kx, kx->kpub->K, kx->C, C, R),
+ algs->hashsz)) == 0)
+ goto badcheck;
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: computed reply = %s", gestr(gg, r));
- trace(T_CRYPTO, "crypto: recovered log = %s", mpstr(cv));
+ trace(T_CRYPTO, "crypto: computed reply = %s", g->ops->gestr(g, R));
+ trace(T_CRYPTO, "crypto: recovered log = %s", g->ops->scstr(g, c));
}))
- if (MP_CMP(cv, >, gg->r) ||
- (G_EXP(gg, cc, gg->g, cv), !G_EQ(gg, c, cc)))
- goto badcheck;
+ CC = g->ops->mul(g, c, 0);
+ if (!g->ops->eq(g, CC, C)) goto badcheck;
/* --- Fill in a new challenge block --- */
kxc = kxc_new(kx);
- G_COPY(gg, kxc->c, c);
- G_COPY(gg, kxc->r, r);
+ kxc->C = C; C = 0;
+ kxc->R = R; R = 0;
- h = GH_INIT(algs.h);
- HASH_STRING(h, "tripe-check-hash");
- GH_HASH(h, ck, indexsz);
- GH_DONE(h, kxc->ck);
- GH_DESTROY(h);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-check-hash");
+ GH_HASH(h, ck, ixsz);
+ GH_DONE(h, kxc->ck); GH_DESTROY(h);
- h = GH_INIT(algs.h);
- HASH_STRING(h, "tripe-cookie");
- hashge(h, kxc->c);
- GH_DONE(h, kxc->hc);
- GH_DESTROY(h);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-cookie");
+ hashge(h, g, kxc->C);
+ GH_DONE(h, kxc->hc); GH_DESTROY(h);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace_block(T_CRYPTO, "crypto: computed cookie", kxc->hc, algs.hashsz);
+ trace_block(T_CRYPTO, "crypto: computed cookie",
+ kxc->hc, algs->hashsz);
}))
/* --- Work out the shared key --- */
- G_EXP(gg, r, c, kx->alpha);
+ R = g->ops->mul(g, kx->a, kxc->C);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: shared secret = %s", gestr(gg, r));
+ trace(T_CRYPTO, "crypto: shared secret = %s", g->ops->gestr(g, R));
}))
/* --- Compute the switch messages --- */
- h = GH_INIT(algs.h); HASH_STRING(h, "tripe-switch-request");
- hashge(h, kx->c); hashge(h, kxc->c);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-switch-request");
+ hashge(h, g, kx->C); hashge(h, g, kxc->C);
GH_DONE(h, kxc->hswrq_out); GH_DESTROY(h);
- h = GH_INIT(algs.h); HASH_STRING(h, "tripe-switch-confirm");
- hashge(h, kx->c); hashge(h, kxc->c);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-switch-confirm");
+ hashge(h, g, kx->C); hashge(h, g, kxc->C);
GH_DONE(h, kxc->hswok_out); GH_DESTROY(h);
- h = GH_INIT(algs.h); HASH_STRING(h, "tripe-switch-request");
- hashge(h, kxc->c); hashge(h, kx->c);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-switch-request");
+ hashge(h, g, kxc->C); hashge(h, g, kx->C);
GH_DONE(h, kxc->hswrq_in); GH_DESTROY(h);
- h = GH_INIT(algs.h); HASH_STRING(h, "tripe-switch-confirm");
- hashge(h, kxc->c); hashge(h, kx->c);
+ h = GH_INIT(algs->h); HASH_STRING(h, "tripe-switch-confirm");
+ hashge(h, g, kxc->C); hashge(h, g, kx->C);
GH_DONE(h, kxc->hswok_in); GH_DESTROY(h);
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
trace_block(T_CRYPTO, "crypto: outbound switch request",
- kxc->hswrq_out, algs.hashsz);
+ kxc->hswrq_out, algs->hashsz);
trace_block(T_CRYPTO, "crypto: outbound switch confirm",
- kxc->hswok_out, algs.hashsz);
+ kxc->hswok_out, algs->hashsz);
trace_block(T_CRYPTO, "crypto: inbound switch request",
- kxc->hswrq_in, algs.hashsz);
+ kxc->hswrq_in, algs->hashsz);
trace_block(T_CRYPTO, "crypto: inbound switch confirm",
- kxc->hswok_in, algs.hashsz);
+ kxc->hswok_in, algs->hashsz);
}))
/* --- Create a new symmetric keyset --- */
- buf_init(&bb, buf_o, sizeof(buf_o));
- G_TOBUF(gg, &bb, kx->c); x = BLEN(&bb);
- G_TOBUF(gg, &bb, kxc->c); y = BLEN(&bb);
- G_TOBUF(gg, &bb, r); z = BLEN(&bb);
+ buf_init(&bb, buf_o, sizeof(buf_o)); a.k = BBASE(&bb);
+ g->ops->stge(g, &bb, kx->C, DHFMT_HASH); a.x = BLEN(&bb);
+ g->ops->stge(g, &bb, kxc->C, DHFMT_HASH); a.y = BLEN(&bb);
+ g->ops->stge(g, &bb, R, DHFMT_HASH); a.z = BLEN(&bb);
assert(BOK(&bb));
- kxc->ks = ks_gen(BBASE(&bb), x, y, z, kx->p);
+ kxc->ks = ks_gen(&a, kx->p);
}
- G_DESTROY(gg, c);
- G_DESTROY(gg, cc);
- G_DESTROY(gg, r);
- mp_drop(cv);
+ if (C) g->ops->freege(g, C);
+ if (CC) g->ops->freege(g, CC);
+ if (R) g->ops->freege(g, R);
+ if (c) g->ops->freesc(g, c);
return (kxc);
badcheck:
a_warn("KX", "?PEER", kx->p, "bad-expected-reply-log", A_END);
goto bad;
bad:
- G_DESTROY(gg, c);
- G_DESTROY(gg, cc);
- G_DESTROY(gg, r);
- mp_drop(cv);
+ if (C) g->ops->freege(g, C);
+ if (CC) g->ops->freege(g, CC);
+ if (R) g->ops->freege(g, R);
+ if (c) g->ops->freesc(g, c);
return (0);
}
{
kxchal *kxc;
buf bb;
- stats *st = p_stats(kx->p);
struct timeval tv;
+ const dhgrp *g = kx->kpriv->grp;
+ octet *p;
+ size_t sz;
buf *b;
switch (kx->s) {
case KXS_CHAL:
- T( trace(T_KEYEXCH, "keyexch: sending prechallenge to `%s'",
- p_name(kx->p)); )
- b = p_txstart(kx->p, MSG_KEYEXCH | KX_PRECHAL);
- G_TOBUF(gg, b, kx->c);
+ if (!kx->p->spec.knock) {
+ T( trace(T_KEYEXCH, "keyexch: sending prechallenge to `%s'",
+ p_name(kx->p)); )
+ b = p_txstart(kx->p, MSG_KEYEXCH | KX_PRECHAL);
+ g->ops->stge(g, b, kx->C, DHFMT_VAR);
+ } else {
+ T( trace(T_KEYEXCH, "keyexch: sending token-request to `%s'",
+ p_name(kx->p)); )
+ b = p_txstart(kx->p, MSG_KEYEXCH | KX_TOKENRQ);
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ c_new(0, 0, &bb); assert(BOK(&bb)); buf_putbuf16(b, &bb);
+
+ buf_putu32(b, kx->kpub->id);
+
+ buf_init(&bb, buf_t, sizeof(buf_t));
+ buf_putstr16(&bb, kx->p->spec.knock);
+ sz = BLEN(&bb)%64; if (sz) sz = 64 - sz;
+ p = buf_get(&bb, sz); assert(p); memset(p, 0, sz);
+ assert(BOK(&bb)); buf_flip(&bb);
+ if (ies_encrypt(kx->kpub, MSG_KEYEXCH | KX_TOKENRQ, &bb, b))
+ buf_break(b);
+ }
break;
case KXS_COMMIT:
T( trace(T_KEYEXCH, "keyexch: sending switch request to `%s'",
p_name(kx->p)); )
kxc = kx->r[0];
b = p_txstart(kx->p, MSG_KEYEXCH | KX_SWITCH);
- buf_put(b, kx->hc, algs.hashsz);
- buf_put(b, kxc->hc, algs.hashsz);
+ buf_put(b, kx->hc, kx->kpriv->algs.hashsz);
+ buf_put(b, kxc->hc, kx->kpriv->algs.hashsz);
buf_init(&bb, buf_i, sizeof(buf_i));
- G_TORAW(gg, &bb, kxc->r);
- buf_put(&bb, kxc->hswrq_out, algs.hashsz);
+ g->ops->stge(g, &bb, kxc->R, DHFMT_STD);
+ buf_put(&bb, kxc->hswrq_out, kx->kpriv->algs.hashsz);
buf_flip(&bb);
ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_SWITCH, &bb, b);
break;
kxc = kx->r[0];
b = p_txstart(kx->p, MSG_KEYEXCH | KX_SWITCHOK);
buf_init(&bb, buf_i, sizeof(buf_i));
- buf_put(&bb, kxc->hswok_out, algs.hashsz);
+ buf_put(&bb, kxc->hswok_out, kx->kpriv->algs.hashsz);
buf_flip(&bb);
ks_encrypt(kxc->ks, MSG_KEYEXCH | KX_SWITCHOK, &bb, b);
break;
}
if (BOK(b)) {
- st->n_kxout++;
- st->sz_kxout += BLEN(b);
+ update_stats_tx(kx, BLEN(b));
p_txend(kx->p);
}
if (kx->s < KXS_SWITCH) {
- gettimeofday(&tv, 0);
- tv.tv_sec += T_RETRY;
+ rs_time(&kx->rs, &tv, 0);
settimer(kx, &tv);
}
}
static int checkresponse(keyexch *kx, unsigned msg, buf *b)
{
- ge *r = G_CREATE(gg);
+ const dhgrp *g = kx->kpriv->grp;
+ dhge *R;
- if (G_FROMRAW(gg, b, r)) {
+ if ((R = g->ops->ldge(g, b, DHFMT_STD)) == 0) {
a_warn("KX", "?PEER", kx->p, "invalid", "%s", pkname[msg], A_END);
goto bad;
}
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: reply = %s", gestr(gg, r));
+ trace(T_CRYPTO, "crypto: reply = %s", g->ops->gestr(g, R));
}))
- if (!G_EQ(gg, r, kx->rx)) {
+ if (!g->ops->eq(g, R, kx->RX)) {
a_warn("KX", "?PEER", kx->p, "incorrect", "response", A_END);
goto bad;
}
- G_DESTROY(gg, r);
+ g->ops->freege(g, R);
return (0);
bad:
- G_DESTROY(gg, r);
+ if (R) g->ops->freege(g, R);
return (-1);
}
static void kxfinish(keyexch *kx)
{
kxchal *kxc = kx->r[0];
- struct timeval tv;
+ struct timeval now, tv;
ks_activate(kxc->ks);
- gettimeofday(&tv, 0);
- tv.tv_sec += T_REGEN;
+ gettimeofday(&now, 0);
+ f2tv(&tv, wobble(T_REGEN));
+ TV_ADD(&tv, &now, &tv);
settimer(kx, &tv);
kx->s = KXS_SWITCH;
a_notify("KXDONE", "?PEER", kx->p, A_END);
static int doswitch(keyexch *kx, buf *b)
{
+ size_t hsz = kx->kpriv->algs.hashsz;
const octet *hc_in, *hc_out, *hswrq;
kxchal *kxc;
- if ((hc_in = buf_get(b, algs.hashsz)) == 0 ||
- (hc_out = buf_get(b, algs.hashsz)) == 0) {
+ if ((hc_in = buf_get(b, hsz)) == 0 ||
+ (hc_out = buf_get(b, hsz)) == 0) {
a_warn("KX", "?PEER", kx->p, "invalid", "switch-rq", A_END);
goto bad;
}
IF_TRACING(T_KEYEXCH, IF_TRACING(T_CRYPTO, {
- trace_block(T_CRYPTO, "crypto: challenge", hc_in, algs.hashsz);
- trace_block(T_CRYPTO, "crypto: cookie", hc_out, algs.hashsz);
+ trace_block(T_CRYPTO, "crypto: challenge", hc_in, hsz);
+ trace_block(T_CRYPTO, "crypto: cookie", hc_out, hsz);
}))
if ((kxc = kxc_byhc(kx, hc_in)) == 0 ||
- memcmp(hc_out, kx->hc, algs.hashsz) != 0) {
+ memcmp(hc_out, kx->hc, hsz) != 0) {
a_warn("KX", "?PEER", kx->p, "incorrect", "switch-rq", A_END);
goto bad;
}
if (decryptrest(kx, kxc, KX_SWITCH, b) ||
checkresponse(kx, KX_SWITCH, b))
goto bad;
- if ((hswrq = buf_get(b, algs.hashsz)) == 0 || BLEFT(b)) {
+ if ((hswrq = buf_get(b, hsz)) == 0 || BLEFT(b)) {
a_warn("KX", "?PEER", kx->p, "invalid", "switch-rq", A_END);
goto bad;
}
IF_TRACING(T_KEYEXCH, {
- trace_block(T_CRYPTO, "crypto: switch request hash", hswrq, algs.hashsz);
+ trace_block(T_CRYPTO, "crypto: switch request hash", hswrq, hsz);
})
- if (memcmp(hswrq, kxc->hswrq_in, algs.hashsz) != 0) {
+ if (memcmp(hswrq, kxc->hswrq_in, hsz) != 0) {
a_warn("KX", "?PEER", kx->p, "incorrect", "switch-rq", A_END);
goto bad;
}
static int doswitchok(keyexch *kx, buf *b)
{
+ size_t hsz = kx->kpriv->algs.hashsz;
const octet *hswok;
kxchal *kxc;
buf bb;
buf_init(&bb, buf_o, sizeof(buf_o));
if (decryptrest(kx, kxc, KX_SWITCHOK, b))
goto bad;
- if ((hswok = buf_get(b, algs.hashsz)) == 0 || BLEFT(b)) {
+ if ((hswok = buf_get(b, hsz)) == 0 || BLEFT(b)) {
a_warn("KX", "?PEER", kx->p, "invalid", "switch-ok", A_END);
goto bad;
}
IF_TRACING(T_KEYEXCH, {
trace_block(T_CRYPTO, "crypto: switch confirmation hash",
- hswok, algs.hashsz);
+ hswok, hsz);
})
- if (memcmp(hswok, kxc->hswok_in, algs.hashsz) != 0) {
+ if (memcmp(hswok, kxc->hswok_in, hsz) != 0) {
a_warn("KX", "?PEER", kx->p, "incorrect", "switch-ok", A_END);
goto bad;
}
static void stop(keyexch *kx)
{
+ const dhgrp *g = kx->kpriv->grp;
unsigned i;
if (kx->f & KXF_DEAD)
sel_rmtimer(&kx->t);
for (i = 0; i < kx->nr; i++)
kxc_destroy(kx->r[i]);
- mp_drop(kx->alpha);
- G_DESTROY(gg, kx->c);
- G_DESTROY(gg, kx->rx);
+ g->ops->freesc(g, kx->a);
+ g->ops->freege(g, kx->C);
+ g->ops->freege(g, kx->RX);
kx->t_valid = 0;
kx->f |= KXF_DEAD;
kx->f &= ~KXF_TIMER;
static void start(keyexch *kx, time_t now)
{
+ algswitch *algs = &kx->kpriv->algs;
+ const dhgrp *g = kx->kpriv->grp;
ghash *h;
assert(kx->f & KXF_DEAD);
kx->f &= ~(KXF_DEAD | KXF_CORK);
kx->nr = 0;
- kx->alpha = mprand_range(MP_NEW, gg->r, &rand_global, 0);
- kx->c = G_CREATE(gg); G_EXP(gg, kx->c, gg->g, kx->alpha);
- kx->rx = G_CREATE(gg); G_EXP(gg, kx->rx, kx->kpub, kx->alpha);
+ kx->a = g->ops->randsc(g);
+ kx->C = g->ops->mul(g, kx->a, 0);
+ kx->RX = g->ops->mul(g, kx->a, kx->kpub->K);
kx->s = KXS_CHAL;
kx->t_valid = now + T_VALID;
- h = GH_INIT(algs.h);
+ h = GH_INIT(algs->h);
HASH_STRING(h, "tripe-cookie");
- hashge(h, kx->c);
+ hashge(h, g, kx->C);
GH_DONE(h, kx->hc);
GH_DESTROY(h);
IF_TRACING(T_KEYEXCH, {
trace(T_KEYEXCH, "keyexch: creating new challenge");
IF_TRACING(T_CRYPTO, {
- trace(T_CRYPTO, "crypto: secret = %s", mpstr(kx->alpha));
- trace(T_CRYPTO, "crypto: challenge = %s", gestr(gg, kx->c));
- trace(T_CRYPTO, "crypto: expected response = %s", gestr(gg, kx->rx));
- trace_block(T_CRYPTO, "crypto: challenge cookie", kx->hc, algs.hashsz);
+ trace(T_CRYPTO, "crypto: secret = %s", g->ops->scstr(g, kx->a));
+ trace(T_CRYPTO, "crypto: challenge = %s", g->ops->gestr(g, kx->C));
+ trace(T_CRYPTO, "crypto: expected response = %s",
+ g->ops->gestr(g, kx->RX));
+ trace_block(T_CRYPTO, "crypto: challenge cookie",
+ kx->hc, algs->hashsz);
})
})
}
static int checkpub(keyexch *kx)
{
time_t now;
+ unsigned f = 0;
+
if (kx->f & KXF_DEAD)
return (-1);
now = time(0);
- if (KEY_EXPIRED(now, kx->texp_kpub)) {
+ if (KEY_EXPIRED(now, kx->kpriv->t_exp)) f |= 1;
+ if (KEY_EXPIRED(now, kx->kpub->t_exp)) f |= 2;
+ if (f) {
stop(kx);
- a_warn("KX", "?PEER", kx->p, "public-key-expired", A_END);
- G_COPY(gg, kx->kpub, gg->i);
+ if (f & 1) a_warn("KX", "?PEER", kx->p, "private-key-expired", A_END);
+ if (f & 2) a_warn("KX", "?PEER", kx->p, "public-key-expired", A_END);
kx->f &= ~KXF_PUBKEY;
return (-1);
}
/* --- @kx_message@ --- *
*
* Arguments: @keyexch *kx@ = pointer to key exchange context
+ * @const addr *a@ = sender's IP address and port
* @unsigned msg@ = the message code
* @buf *b@ = pointer to buffer containing the packet
*
- * Returns: ---
+ * Returns: Nonzero if the sender's address was unknown.
*
* Use: Reads a packet containing key exchange messages and handles
* it.
*/
-void kx_message(keyexch *kx, unsigned msg, buf *b)
+int kx_message(keyexch *kx, const addr *a, unsigned msg, buf *b)
{
- struct timeval now, tv;
- stats *st = p_stats(kx->p);
size_t sz = BSZ(b);
int rc;
- gettimeofday(&now, 0);
- if (kx->f & KXF_CORK) {
- start(kx, now.tv_sec);
- TV_ADDL(&tv, &now, T_RETRY, 0);
- settimer(kx, &tv);
- a_notify("KXSTART", A_END);
- }
+ T( trace(T_KEYEXCH, "keyexch: processing %s packet from %c%s%c",
+ msg < KX_NMSG ? pkname[msg] : "unknown",
+ kx ? '`' : '<', kx ? p_name(kx->p) : "nil", kx ? '\'' : '>'); )
- if (checkpub(kx))
- return;
-
- if (!VALIDP(kx, now.tv_sec)) {
- stop(kx);
- start(kx, now.tv_sec);
+ switch (msg) {
+ case KX_TOKENRQ: dotokenrq(a, b); return (0);
+ case KX_KNOCK: doknock(a, b); return (0);
}
- T( trace(T_KEYEXCH, "keyexch: processing %s packet from `%s'",
- msg < KX_NMSG ? pkname[msg] : "unknown", p_name(kx->p)); )
+
+ if (!kx) return (-1);
+ if (notice_message(kx)) return (0);
switch (msg) {
- case KX_PRECHAL:
- rc = doprechallenge(kx, b);
- break;
- case KX_CHAL:
- rc = dochallenge(kx, b);
- break;
- case KX_REPLY:
- rc = doreply(kx, b);
- break;
- case KX_SWITCH:
- rc = doswitch(kx, b);
- break;
- case KX_SWITCHOK:
- rc = doswitchok(kx, b);
- break;
+ case KX_TOKEN: rc = dotoken(kx, b); break;
+ case KX_PRECHAL: rc = doprechallenge(kx, b); break;
+ case KX_CHAL: rc = dochallenge(kx, b); break;
+ case KX_REPLY: rc = doreply(kx, b); break;
+ case KX_SWITCH: rc = doswitch(kx, b); break;
+ case KX_SWITCHOK: rc = doswitchok(kx, b); break;
default:
a_warn("KX", "?PEER", kx->p, "unknown-message", "0x%02x", msg, A_END);
rc = -1;
break;
}
- if (rc)
- st->n_reject++;
- else {
- st->n_kxin++;
- st->sz_kxin += sz;
- }
+ update_stats_rx(kx, !rc, sz);
+ return (0);
}
/* --- @kx_free@ --- *
void kx_free(keyexch *kx)
{
stop(kx);
- G_DESTROY(gg, kx->kpub);
+ km_unref(kx->kpub);
+ km_unref(kx->kpriv);
}
/* --- @kx_newkeys@ --- *
void kx_newkeys(keyexch *kx)
{
- if (km_getpubkey(p_tag(kx->p), kx->kpub, &kx->texp_kpub))
- return;
+ kdata *kpriv, *kpub;
+ unsigned i;
+ int switchp;
+ time_t now = time(0);
+
+ T( trace(T_KEYEXCH, "keyexch: checking new keys for `%s'",
+ p_name(kx->p)); )
+
+ /* --- Find out whether we can use new keys --- *
+ *
+ * Try each available combination of new and old, public and private,
+ * except both old (which is status quo anyway). The selection is encoded
+ * in @i@, with bit 0 for the private key and bit 1 for public key; a set
+ * bit means to use the old value, and a clear bit means to use the new
+ * one.
+ *
+ * This means that we currently prefer `old private and new public' over
+ * `new private and old public'. I'm not sure which way round this should
+ * actually be.
+ */
+
+ for (i = 0; i < 3; i++) {
+
+ /* --- Select the keys we're going to examine --- *
+ *
+ * If we're meant to have a new key and don't, then skip this
+ * combination.
+ */
+
+ T( trace(T_KEYEXCH, "keyexch: checking %s private, %s public",
+ i & 1 ? "old" : "new", i & 2 ? "old" : "new"); )
+
+ if (i & 1) kpriv = kx->kpriv;
+ else if (kx->kpriv->kn->kd != kx->kpriv) kpriv = kx->kpriv->kn->kd;
+ else {
+ T( trace(T_KEYEXCH, "keyexch: private key unchanged, skipping"); )
+ continue;
+ }
+
+ if (i & 2) kpub = kx->kpub;
+ else if (kx->kpub->kn->kd != kx->kpub) kpub = kx->kpub->kn->kd;
+ else {
+ T( trace(T_KEYEXCH, "keyexch: public key unchanged, skipping"); )
+ continue;
+ }
+
+ /* --- Skip if either key is expired --- *
+ *
+ * We're not going to get far with expired keys, and this simplifies the
+ * logic below.
+ */
+
+ if (KEY_EXPIRED(now, kx->kpriv->t_exp) ||
+ KEY_EXPIRED(now, kx->kpub->t_exp)) {
+ T( trace(T_KEYEXCH, "keyexch: %s expired, skipping",
+ !KEY_EXPIRED(now, kx->kpriv->t_exp) ? "public key" :
+ !KEY_EXPIRED(now, kx->kpub->t_exp) ? "private key" :
+ "both keys"); )
+ continue;
+ }
+
+ /* --- If the groups don't match then we can't use this pair --- */
+
+ if (!km_samealgsp(kpriv, kpub)) {
+ T( trace(T_KEYEXCH, "keyexch: peer `%s' group mismatch; "
+ "%s priv `%s' and %s pub `%s'", p_name(kx->p),
+ i & 1 ? "old" : "new", km_tag(kx->kpriv),
+ i & 2 ? "old" : "new", km_tag(kx->kpub)); )
+ continue;
+ }
+ goto newkeys;
+ }
+ T( trace(T_KEYEXCH, "keyexch: peer `%s' continuing with old keys",
+ p_name(kx->p)); )
+ return;
+
+ /* --- We've chosen new keys --- *
+ *
+ * Switch the new ones into place. Neither of the keys we're switching to
+ * is expired (we checked that above), so we should just crank everything
+ * up.
+ *
+ * A complication arises: we don't really want to force a new key exchange
+ * unless we have to. If the group is unchanged, and we're currently
+ * running OK, then we should just let things lie.
+ */
+
+newkeys:
+ switchp = ((kx->f & KXF_DEAD) ||
+ kx->s != KXS_SWITCH ||
+ kpriv->grp->ops != kx->kpriv->grp->ops ||
+ !kpriv->grp->ops->samegrpp(kpriv->grp, kx->kpriv->grp));
+
+ T( trace(T_KEYEXCH, "keyexch: peer `%s' adopting "
+ "%s priv `%s' and %s pub `%s'; %sforcing exchange", p_name(kx->p),
+ i & 1 ? "old" : "new", km_tag(kx->kpriv),
+ i & 2 ? "old" : "new", km_tag(kx->kpub),
+ switchp ? "" : "not "); )
+
+ if (switchp) stop(kx);
+ km_ref(kpriv); km_unref(kx->kpriv); kx->kpriv = kpriv;
+ km_ref(kpub); km_unref(kx->kpub); kx->kpub = kpub;
kx->f |= KXF_PUBKEY;
- if ((kx->f & KXF_DEAD) || kx->s != KXS_SWITCH) {
+ if (switchp) {
T( trace(T_KEYEXCH, "keyexch: restarting key negotiation with `%s'",
p_name(kx->p)); )
- stop(kx);
start(kx, time(0));
resend(kx);
}
}
-/* --- @kx_init@ --- *
+/* --- @kx_setup@ --- *
*
* Arguments: @keyexch *kx@ = pointer to key exchange context
* @peer *p@ = pointer to peer context
* exchange.
*/
-int kx_init(keyexch *kx, peer *p, keyset **ks, unsigned f)
+int kx_setup(keyexch *kx, peer *p, keyset **ks, unsigned f)
{
+ if ((kx->kpriv = km_findpriv(p_privtag(p))) == 0) goto fail_0;
+ if ((kx->kpub = km_findpub(p_tag(p))) == 0) goto fail_1;
+ if (!km_samealgsp(kx->kpriv, kx->kpub)) {
+ a_warn("KX", "?PEER", p, "group-mismatch",
+ "local-private-key", "%s", p_privtag(p),
+ "peer-public-key", "%s", p_tag(p),
+ A_END);
+ goto fail_2;
+ }
+
kx->ks = ks;
kx->p = p;
- kx->kpub = G_CREATE(gg);
- if (km_getpubkey(p_tag(p), kx->kpub, &kx->texp_kpub)) {
- G_DESTROY(gg, kx->kpub);
- return (-1);
- }
kx->f = KXF_DEAD | KXF_PUBKEY | f;
+ rs_reset(&kx->rs);
if (!(kx->f & KXF_CORK)) {
start(kx, time(0));
resend(kx);
/* Don't notify here: the ADD message hasn't gone out yet. */
}
return (0);
+
+fail_2:
+ km_unref(kx->kpub);
+fail_1:
+ km_unref(kx->kpriv);
+fail_0:
+ return (-1);
}
+/* --- @kx_init@ --- *
+ *
+ * Arguments: ---
+ *
+ * Returns: ---
+ *
+ * Use: Initializes the key-exchange logic.
+ */
+
+void kx_init(void)
+ { ratelim_init(&unauth_limit, 20, 500); }
+
/*----- That's all, folks -------------------------------------------------*/
~mdw / tripe / blobdiff