+ /* --- The hash length varies with the key --- *
+ *
+ * So we have to unpack once for each key. This isn't too bad.
+ */
+
+ g.r = &rand_global;
+ g.u = 0;
+ key_mkiter(&ki, &f);
+ while ((k = key_next(&ki)) != 0) {
+ if (key_expired(k)) continue;
+ if (strcmp(k->type, "become") != 0) continue;
+
+ /* --- Get a hash function --- */
+
+ if ((p = key_getattr(&f, k, "hash")) == 0)
+ p = "sha";
+ if ((g.h = ghash_byname(p)) == 0)
+ continue;
+
+ /* --- Unpack the key --- */
+
+ p = key_getattr(&f, k, "sig");
+ if (!p || strcmp(p, "dsa") == 0) {
+ dh_pub dp;
+ kp = key_fetchinit(dh_pubfetch, 0, &dp);
+ if (key_fetch(kp, k)) goto fail_1;
+ if ((g.g = group_prime(&dp.dp)) == 0) goto fail_1;
+ g.p = G_CREATE(g.g);
+ if (G_FROMINT(g.g, g.p, dp.y)) goto fail_2;
+ } else if (strcmp(p, "ecdsa") == 0) {
+ ec_pub ep;
+ ec_info ei;
+ kp = key_fetchinit(ec_pubfetch, 0, &ep);
+ if (key_fetch(kp, k)) goto fail_1;
+ if (ec_getinfo(&ei, ep.cstr)) goto fail_1;
+ g.g = group_ec(&ei);
+ g.p = G_CREATE(g.g);
+ if (G_FROMEC(g.g, g.p, &ep.p)) goto fail_2;
+ } else
+ goto fail_0;
+
+ /* --- Unpack the response --- */
+
+ h = GH_INIT(g.h);
+ GH_HASH(h, buff, rqlen);
+ buf_init(&b, rbuff, sz);
+ if (buf_ensure(&b, g.h->hashsz)) goto fail_3;
+ if (memcmp(BCUR(&b), GH_DONE(h, 0), g.h->hashsz) != 0) goto fail_3;
+ BSTEP(&b, g.h->hashsz);
+ if ((ans = buf_getbyte(&b)) < 0) goto fail_3;
+ GH_DESTROY(h);
+
+ /* --- Verify the signature --- */
+
+ h = gdsa_beginhash(&g);
+ GH_HASH(h, BBASE(&b), BLEN(&b));
+ gdsa_endhash(&g, h);
+ s.r = s.s = 0;
+ if ((s.r = buf_getmp(&b)) == 0 ||
+ (s.s = buf_getmp(&b)) == 0)
+ goto fail_4;
+ if (gdsa_verify(&g, &s, GH_DONE(h, 0)))
+ goto fail_4;
+
+ mp_drop(s.r); mp_drop(s.s);
+ GH_DESTROY(h);
+ G_DESTROY(g.g, g.p);
+ G_DESTROYGROUP(g.g);
+ key_fetchdone(kp);
+ key_close(&f);
+ return (ans);
+
+ /* --- Tidy up and try again --- */
+
+ fail_4:
+ mp_drop(s.r); mp_drop(s.s);
+ fail_3:
+ GH_DESTROY(h);
+ G_DESTROY(g.g, g.p);
+ fail_2:
+ G_DESTROYGROUP(g.g);
+ fail_1:
+ key_fetchdone(kp);
+ fail_0:
+ continue;
+ }
+
+ T( trace(TRACE_CLIENT,
+ "client: invalid or corrupt reply packet"); )