Adding upstream version 3.2.1.upstream/3.2.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 296 insertions, 0 deletions

diff --git a/lib/cookies/helper.c b/lib/cookies/helper.c
new file mode 100644
index 0000000..e07b8cb
--- /dev/null
+++ b/lib/cookies/helper.c
@@ -0,0 +1,296 @@
+/*  Copyright (C) 2016-2017 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+    This program 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.
+
+    This program 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 this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <assert.h>
+#include <libknot/rrtype/opt.h>
+#include <libknot/rrtype/opt-cookie.h>
+
+#include "lib/cookies/helper.h"
+#include "lib/defines.h"
+
+/**
+ * @brief Check whether there is a cached cookie that matches the current
+ *        client cookie.
+ */
+static const uint8_t *peek_and_check_cc(kr_cookie_lru_t *cache, const void *sa,
+                                        const uint8_t *cc, uint16_t cc_len)
+{
+	assert(cache && sa && cc && cc_len);
+
+	const uint8_t *cached_opt = kr_cookie_lru_get(cache, sa);
+	if (!cached_opt) {
+		return NULL;
+	}
+
+	const uint8_t *cached_cc = knot_edns_opt_get_data((uint8_t *) cached_opt);
+
+	if (cc_len == KNOT_OPT_COOKIE_CLNT &&
+	    0 == memcmp(cc, cached_cc, cc_len)) {
+		return cached_opt;
+	}
+
+	return NULL;
+}
+
+/**
+ * @brief Put a client cookie into the RR Set.
+ */
+static int opt_rr_put_cookie(knot_rrset_t *opt_rr, uint8_t *data,
+                             uint16_t data_len, knot_mm_t *mm)
+{
+	assert(opt_rr && data && data_len > 0);
+
+	const uint8_t *cc = NULL, *sc = NULL;
+	uint16_t cc_len = 0, sc_len = 0;
+
+	int ret = knot_edns_opt_cookie_parse(data, data_len, &cc, &cc_len,
+	                                     &sc, &sc_len);
+	if (ret != KNOT_EOK) {
+		return kr_error(EINVAL);
+	}
+	assert(data_len == cc_len + sc_len);
+
+	uint16_t cookies_size = data_len;
+	uint8_t *cookies_data = NULL;
+
+	ret = knot_edns_reserve_unique_option(opt_rr, KNOT_EDNS_OPTION_COOKIE,
+	                                      cookies_size, &cookies_data, mm);
+	if (ret != KNOT_EOK) {
+		return kr_error(EINVAL);
+	}
+	assert(cookies_data != NULL);
+
+	cookies_size = knot_edns_opt_cookie_write(cc, cc_len, sc, sc_len,
+	                                          cookies_data, cookies_size);
+	if (cookies_size == 0) {
+		return kr_error(EINVAL);
+	}
+	assert(cookies_size == data_len);
+
+	return kr_ok();
+}
+
+/**
+ * @brief Puts entire EDNS option into the RR Set.
+ */
+static int opt_rr_put_cookie_opt(knot_rrset_t *opt_rr, uint8_t *option, knot_mm_t *mm)
+{
+	assert(opt_rr && option);
+
+	uint16_t opt_code = knot_edns_opt_get_code(option);
+	if (opt_code != KNOT_EDNS_OPTION_COOKIE) {
+		return kr_error(EINVAL);
+	}
+
+	uint16_t opt_len = knot_edns_opt_get_length(option);
+	uint8_t *opt_data = knot_edns_opt_get_data(option);
+	if (!opt_data || opt_len == 0) {
+		return kr_error(EINVAL);
+	}
+
+	return opt_rr_put_cookie(opt_rr, opt_data, opt_len, mm);
+}
+
+int kr_request_put_cookie(const struct kr_cookie_comp *clnt_comp,
+                          kr_cookie_lru_t *cookie_cache,
+                          const struct sockaddr *clnt_sa,
+                          const struct sockaddr *srvr_sa,
+                          struct kr_request *req)
+{
+	if (!clnt_comp || !req) {
+		return kr_error(EINVAL);
+	}
+
+	if (!req->ctx->opt_rr) {
+		return kr_ok();
+	}
+
+	if (!clnt_comp->secr || (clnt_comp->alg_id < 0) || !cookie_cache) {
+		return kr_error(EINVAL);
+	}
+
+	/*
+	 * Generate client cookie from client address, server address and
+	 * secret quantity.
+	 */
+	struct knot_cc_input input = {
+		.clnt_sockaddr = clnt_sa,
+		.srvr_sockaddr = srvr_sa,
+		.secret_data = clnt_comp->secr->data,
+		.secret_len = clnt_comp->secr->size
+	};
+	uint8_t cc[KNOT_OPT_COOKIE_CLNT];
+	uint16_t cc_len = KNOT_OPT_COOKIE_CLNT;
+	const struct knot_cc_alg *cc_alg = kr_cc_alg_get(clnt_comp->alg_id);
+	if (!cc_alg) {
+		return kr_error(EINVAL);
+	}
+	assert(cc_alg->gen_func);
+	cc_len = cc_alg->gen_func(&input, cc, cc_len);
+	if (cc_len != KNOT_OPT_COOKIE_CLNT) {
+		return kr_error(EINVAL);
+	}
+
+	const uint8_t *cached_cookie = peek_and_check_cc(cookie_cache,
+	                                                 srvr_sa, cc, cc_len);
+
+	/* Add cookie option. */
+	int ret;
+	if (cached_cookie) {
+		ret = opt_rr_put_cookie_opt(req->ctx->opt_rr,
+		                            (uint8_t *)cached_cookie,
+		                            req->ctx->pool);
+	} else {
+		ret = opt_rr_put_cookie(req->ctx->opt_rr, cc, cc_len,
+		                        req->ctx->pool);
+	}
+
+	return ret;
+}
+
+int kr_answer_write_cookie(struct knot_sc_input *sc_input,
+                           const struct kr_nonce_input *nonce,
+                           const struct knot_sc_alg *alg, knot_pkt_t *pkt)
+{
+	if (!sc_input || !sc_input->cc || sc_input->cc_len == 0) {
+		return kr_error(EINVAL);
+	}
+
+	if (!sc_input->srvr_data || !sc_input->srvr_data->clnt_sockaddr ||
+	    !sc_input->srvr_data->secret_data ||
+	    !sc_input->srvr_data->secret_len) {
+		return kr_error(EINVAL);
+	}
+
+	if (!nonce) {
+		return kr_error(EINVAL);
+	}
+
+	if (!alg || !alg->hash_size || !alg->hash_func) {
+		return kr_error(EINVAL);
+	}
+
+	if (!pkt || !pkt->opt_rr) {
+		return kr_error(EINVAL);
+	}
+
+	uint16_t nonce_len = KR_NONCE_LEN;
+	uint16_t hash_len = alg->hash_size;
+
+	/*
+	 * Space for cookie is reserved inside the EDNS OPT RR of
+	 * the answer packet.
+	 */
+	uint8_t *cookie = NULL;
+	uint16_t cookie_len = knot_edns_opt_cookie_data_len(sc_input->cc_len,
+	                                                    nonce_len + hash_len);
+	if (cookie_len == 0) {
+		return kr_error(EINVAL);
+	}
+
+	int ret = knot_edns_reserve_unique_option(pkt->opt_rr,
+	                                          KNOT_EDNS_OPTION_COOKIE,
+	                                          cookie_len, &cookie,
+	                                          &pkt->mm);
+	if (ret != KNOT_EOK) {
+		return kr_error(ENOMEM);
+	}
+	assert(cookie != NULL);
+
+	/*
+	 * Function knot_edns_opt_cookie_data_len() returns the sum of its
+	 * parameters or zero. Anyway, let's check again.
+	 */
+	if (cookie_len < (sc_input->cc_len + nonce_len + hash_len)) {
+		return kr_error(EINVAL);
+	}
+
+	/* Copy client cookie data portion. */
+	memcpy(cookie, sc_input->cc, sc_input->cc_len);
+
+	if (nonce_len) {
+		/* Write nonce data portion. */
+		kr_nonce_write_wire(cookie + sc_input->cc_len, nonce_len,
+		                    nonce);
+		/* Adjust input for written nonce value. */
+		sc_input->nonce = cookie + sc_input->cc_len;
+		sc_input->nonce_len = nonce_len;
+	}
+
+	hash_len = alg->hash_func(sc_input,
+	                          cookie + sc_input->cc_len + nonce_len,
+	                          hash_len);
+	/* Zero nonce values. */
+	sc_input->nonce = NULL;
+	sc_input->nonce_len = 0;
+
+	return (hash_len != 0) ? kr_ok() : kr_error(EINVAL);
+}
+
+int kr_pkt_set_ext_rcode(knot_pkt_t *pkt, uint16_t whole_rcode)
+{
+	/*
+	 * RFC6891 6.1.3 -- extended RCODE forms the upper 8 bits of whole
+	 * 12-bit RCODE (together with the 4 bits of 'normal' RCODE).
+	 *
+	 * | 11 10 09 08 07 06 05 04 | 03 02 01 00 |
+	 * |          12-bit whole RCODE           |
+	 * |   8-bit extended RCODE  | 4-bit RCODE |
+	 */
+
+	if (!pkt || !knot_pkt_has_edns(pkt)) {
+		return kr_error(EINVAL);
+	}
+
+	uint8_t rcode = whole_rcode & 0x0f;
+	uint8_t ext_rcode = whole_rcode >> 4;
+	knot_wire_set_rcode(pkt->wire, rcode);
+	knot_edns_set_ext_rcode(pkt->opt_rr, ext_rcode);
+
+	return kr_ok();
+}
+
+uint8_t *kr_no_question_cookie_query(const knot_pkt_t *pkt)
+{
+	if (!pkt || knot_wire_get_qdcount(pkt->wire) > 0) {
+		return false;
+	}
+
+	if (knot_wire_get_qr(pkt->wire) != 0 || !pkt->opt_rr) {
+		return false;
+	}
+
+	return knot_edns_get_option(pkt->opt_rr, KNOT_EDNS_OPTION_COOKIE);
+}
+
+int kr_parse_cookie_opt(uint8_t *cookie_opt, struct knot_dns_cookies *cookies)
+{
+	if (!cookie_opt || !cookies) {
+		return kr_error(EINVAL);
+	}
+
+	const uint8_t *cookie_data = knot_edns_opt_get_data(cookie_opt);
+	uint16_t cookie_len = knot_edns_opt_get_length(cookie_opt);
+	if (!cookie_data || cookie_len == 0) {
+		return kr_error(EINVAL);
+	}
+
+	int ret =  knot_edns_opt_cookie_parse(cookie_data, cookie_len,
+	                                      &cookies->cc, &cookies->cc_len,
+	                                      &cookies->sc, &cookies->sc_len);
+
+	return (ret == KNOT_EOK) ? kr_ok() : kr_error(EINVAL);
+}