Add TLS 1.3 1-RTT.
This adds the machinery for doing TLS 1.3 1RTT.
Change-Id: I736921ffe9dc6f6e64a08a836df6bb166d20f504
Reviewed-on: https://boringssl-review.googlesource.com/8720
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/tls13_enc.c b/ssl/tls13_enc.c
new file mode 100644
index 0000000..ea88675
--- /dev/null
+++ b/ssl/tls13_enc.c
@@ -0,0 +1,344 @@
+/* Copyright (c) 2016, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/ssl.h>
+
+#include <assert.h>
+#include <string.h>
+
+#include <openssl/aead.h>
+#include <openssl/bytestring.h>
+#include <openssl/digest.h>
+#include <openssl/hmac.h>
+#include <openssl/hkdf.h>
+#include <openssl/mem.h>
+
+#include "internal.h"
+
+
+int tls13_init_key_schedule(SSL *ssl, const uint8_t *resumption_ctx,
+ size_t resumption_ctx_len) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+
+ hs->hash_len = EVP_MD_size(digest);
+
+ /* Save the hash of the resumption context. */
+ unsigned resumption_hash_len;
+ if (!EVP_Digest(resumption_ctx, resumption_ctx_len, hs->resumption_hash,
+ &resumption_hash_len, digest, NULL)) {
+ return 0;
+ }
+
+ /* Initialize the secret to the zero key. */
+ memset(hs->secret, 0, hs->hash_len);
+
+ /* Initialize the rolling hashes and release the handshake buffer. */
+ if (!ssl3_init_handshake_hash(ssl)) {
+ return 0;
+ }
+ ssl3_free_handshake_buffer(ssl);
+ return 1;
+}
+
+int tls13_advance_key_schedule(SSL *ssl, const uint8_t *in, size_t len) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+
+ return HKDF_extract(hs->secret, &hs->hash_len, digest, in, len, hs->secret,
+ hs->hash_len);
+}
+
+static int hkdf_expand_label(uint8_t *out, const EVP_MD *digest,
+ const uint8_t *secret, size_t secret_len,
+ const uint8_t *label, size_t label_len,
+ const uint8_t *hash, size_t hash_len, size_t len) {
+ static const char kTLS13LabelVersion[] = "TLS 1.3, ";
+
+ CBB cbb, child;
+ uint8_t *hkdf_label;
+ size_t hkdf_label_len;
+ if (!CBB_init(&cbb, 2 + 1 + strlen(kTLS13LabelVersion) + label_len + 1 +
+ hash_len) ||
+ !CBB_add_u16(&cbb, len) ||
+ !CBB_add_u8_length_prefixed(&cbb, &child) ||
+ !CBB_add_bytes(&child, (const uint8_t *)kTLS13LabelVersion,
+ strlen(kTLS13LabelVersion)) ||
+ !CBB_add_bytes(&child, label, label_len) ||
+ !CBB_add_u8_length_prefixed(&cbb, &child) ||
+ !CBB_add_bytes(&child, hash, hash_len) ||
+ !CBB_finish(&cbb, &hkdf_label, &hkdf_label_len)) {
+ CBB_cleanup(&cbb);
+ return 0;
+ }
+
+ int ret = HKDF_expand(out, len, digest, secret, secret_len, hkdf_label,
+ hkdf_label_len);
+ OPENSSL_free(hkdf_label);
+ return ret;
+}
+
+int tls13_get_context_hashes(SSL *ssl, uint8_t *out, size_t *out_len) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+
+ EVP_MD_CTX ctx;
+ EVP_MD_CTX_init(&ctx);
+ unsigned handshake_len = 0;
+ int ok = EVP_MD_CTX_copy_ex(&ctx, &ssl->s3->handshake_hash) &&
+ EVP_DigestFinal_ex(&ctx, out, &handshake_len);
+ EVP_MD_CTX_cleanup(&ctx);
+ if (!ok) {
+ return 0;
+ }
+
+ memcpy(out + handshake_len, hs->resumption_hash, hs->hash_len);
+ *out_len = handshake_len + hs->hash_len;
+ return 1;
+}
+
+/* derive_secret derives a secret of length |len| and writes the result in |out|
+ * with the given label and the current base secret and most recently-saved
+ * handshake context. It returns one on success and zero on error. */
+static int derive_secret(SSL *ssl, uint8_t *out, size_t len,
+ const uint8_t *label, size_t label_len) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+
+ uint8_t context_hashes[2 * EVP_MAX_MD_SIZE];
+ size_t context_hashes_len;
+ if (!tls13_get_context_hashes(ssl, context_hashes, &context_hashes_len)) {
+ return 0;
+ }
+
+ return hkdf_expand_label(out, digest, hs->secret, hs->hash_len, label,
+ label_len, context_hashes, context_hashes_len, len);
+}
+
+int tls13_set_traffic_key(SSL *ssl, enum tls_record_type_t type,
+ enum evp_aead_direction_t direction,
+ const uint8_t *traffic_secret,
+ size_t traffic_secret_len) {
+ if (traffic_secret_len > 0xff) {
+ OPENSSL_PUT_ERROR(SSL, ERR_R_OVERFLOW);
+ return 0;
+ }
+
+ const char *phase;
+ switch (type) {
+ case type_early_handshake:
+ phase = "early handshake key expansion, ";
+ break;
+ case type_early_data:
+ phase = "early application data key expansion, ";
+ break;
+ case type_handshake:
+ phase = "handshake key expansion, ";
+ break;
+ case type_data:
+ phase = "application data key expansion, ";
+ break;
+ default:
+ return 0;
+ }
+ size_t phase_len = strlen(phase);
+
+ const char *purpose = "client write key";
+ if ((ssl->server && direction == evp_aead_seal) ||
+ (!ssl->server && direction == evp_aead_open)) {
+ purpose = "server write key";
+ }
+ size_t purpose_len = strlen(purpose);
+
+ /* The longest label has length 38 (type_early_data) + 16 (either purpose
+ * value). */
+ uint8_t label[38 + 16];
+ size_t label_len = phase_len + purpose_len;
+ if (label_len > sizeof(label)) {
+ assert(0);
+ return 0;
+ }
+ memcpy(label, phase, phase_len);
+ memcpy(label + phase_len, purpose, purpose_len);
+
+ /* Look up cipher suite properties. */
+ const EVP_AEAD *aead;
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+ size_t mac_secret_len, fixed_iv_len;
+ if (!ssl_cipher_get_evp_aead(&aead, &mac_secret_len, &fixed_iv_len,
+ ssl->session->cipher,
+ ssl3_protocol_version(ssl))) {
+ return 0;
+ }
+
+ /* Derive the key. */
+ size_t key_len = EVP_AEAD_key_length(aead);
+ uint8_t key[EVP_AEAD_MAX_KEY_LENGTH];
+ if (!hkdf_expand_label(key, digest, traffic_secret, traffic_secret_len, label,
+ label_len, NULL, 0, key_len)) {
+ return 0;
+ }
+
+ /* The IV's label ends in "iv" instead of "key". */
+ if (label_len < 3) {
+ assert(0);
+ return 0;
+ }
+ label_len--;
+ label[label_len - 2] = 'i';
+ label[label_len - 1] = 'v';
+
+ /* Derive the IV. */
+ size_t iv_len = EVP_AEAD_nonce_length(aead);
+ uint8_t iv[EVP_AEAD_MAX_NONCE_LENGTH];
+ if (!hkdf_expand_label(iv, digest, traffic_secret, traffic_secret_len, label,
+ label_len, NULL, 0, iv_len)) {
+ return 0;
+ }
+
+ SSL_AEAD_CTX *traffic_aead = SSL_AEAD_CTX_new(direction,
+ ssl3_protocol_version(ssl),
+ ssl->session->cipher,
+ key, key_len, NULL, 0,
+ iv, iv_len);
+ if (traffic_aead == NULL) {
+ return 0;
+ }
+
+ if (direction == evp_aead_open) {
+ if (!ssl->method->set_read_state(ssl, traffic_aead)) {
+ return 0;
+ }
+ } else {
+ if (!ssl->method->set_write_state(ssl, traffic_aead)) {
+ return 0;
+ }
+ }
+
+ /* Save the traffic secret. */
+ if (direction == evp_aead_open) {
+ memcpy(ssl->s3->read_traffic_secret, traffic_secret, traffic_secret_len);
+ ssl->s3->read_traffic_secret_len = traffic_secret_len;
+ } else {
+ memcpy(ssl->s3->write_traffic_secret, traffic_secret, traffic_secret_len);
+ ssl->s3->write_traffic_secret_len = traffic_secret_len;
+ }
+
+ return 1;
+}
+
+static const char kTLS13LabelHandshakeTraffic[] = "handshake traffic secret";
+static const char kTLS13LabelApplicationTraffic[] =
+ "application traffic secret";
+
+int tls13_set_handshake_traffic(SSL *ssl) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+
+ uint8_t traffic_secret[EVP_MAX_MD_SIZE];
+ if (!derive_secret(ssl, traffic_secret, hs->hash_len,
+ (const uint8_t *)kTLS13LabelHandshakeTraffic,
+ strlen(kTLS13LabelHandshakeTraffic)) ||
+ !tls13_set_traffic_key(ssl, type_handshake, evp_aead_open, traffic_secret,
+ hs->hash_len) ||
+ !tls13_set_traffic_key(ssl, type_handshake, evp_aead_seal, traffic_secret,
+ hs->hash_len)) {
+ return 0;
+ }
+ return 1;
+}
+
+int tls13_derive_traffic_secret_0(SSL *ssl) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+
+ return derive_secret(ssl, hs->traffic_secret_0, hs->hash_len,
+ (const uint8_t *)kTLS13LabelApplicationTraffic,
+ strlen(kTLS13LabelApplicationTraffic));
+}
+
+static const char kTLS13LabelExporter[] = "exporter master secret";
+static const char kTLS13LabelResumption[] = "resumption master secret";
+
+int tls13_finalize_keys(SSL *ssl) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+
+ ssl->s3->exporter_secret_len = hs->hash_len;
+ ssl->session->master_key_length = hs->hash_len;
+ if (!derive_secret(
+ ssl, ssl->s3->exporter_secret, ssl->s3->exporter_secret_len,
+ (const uint8_t *)kTLS13LabelExporter, strlen(kTLS13LabelExporter)) ||
+ !derive_secret(ssl, ssl->session->master_key,
+ ssl->session->master_key_length,
+ (const uint8_t *)kTLS13LabelResumption,
+ strlen(kTLS13LabelResumption))) {
+ return 0;
+ }
+
+ return 1;
+}
+
+int tls13_finished_mac(SSL *ssl, uint8_t *out, size_t *out_len, int is_server) {
+ SSL_HANDSHAKE *hs = ssl->s3->hs;
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+
+ uint8_t key[EVP_MAX_MD_SIZE];
+ size_t key_len = EVP_MD_size(digest);
+
+ uint8_t *traffic_secret;
+ const char *label;
+ if (is_server) {
+ label = "server finished";
+ if (ssl->server) {
+ traffic_secret = ssl->s3->write_traffic_secret;
+ } else {
+ traffic_secret = ssl->s3->read_traffic_secret;
+ }
+ } else {
+ label = "client finished";
+ if (!ssl->server) {
+ traffic_secret = ssl->s3->write_traffic_secret;
+ } else {
+ traffic_secret = ssl->s3->read_traffic_secret;
+ }
+ }
+
+ uint8_t context_hashes[2 * EVP_MAX_MD_SIZE];
+ size_t context_hashes_len;
+ unsigned len;
+ if (!hkdf_expand_label(key, digest, traffic_secret, hs->hash_len,
+ (const uint8_t *)label, strlen(label), NULL, 0,
+ hs->hash_len) ||
+ !tls13_get_context_hashes(ssl, context_hashes, &context_hashes_len) ||
+ HMAC(digest, key, key_len, context_hashes, context_hashes_len, out,
+ &len) == NULL) {
+ return 0;
+ }
+ *out_len = len;
+ return 1;
+}
+
+int tls13_export_keying_material(SSL *ssl, uint8_t *out, size_t out_len,
+ const char *label, size_t label_len,
+ const uint8_t *context, size_t context_len,
+ int use_context) {
+ const EVP_MD *digest = ssl_get_handshake_digest(ssl_get_algorithm_prf(ssl));
+
+ const uint8_t *hash = NULL;
+ size_t hash_len = 0;
+ if (use_context) {
+ hash = context;
+ hash_len = context_len;
+ }
+ return hkdf_expand_label(out, digest, ssl->s3->exporter_secret,
+ ssl->s3->exporter_secret_len, (const uint8_t *)label,
+ label_len, hash, hash_len, out_len);
+}