mirror of
https://github.com/pineappleEA/pineapple-src.git
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381 lines
12 KiB
C
381 lines
12 KiB
C
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/* $OpenBSD: tls13_key_schedule.c,v 1.8 2019/11/17 21:01:08 beck Exp $ */
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/* Copyright (c) 2018, Bob Beck <beck@openbsd.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <openssl/hkdf.h>
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#include "bytestring.h"
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#include "tls13_internal.h"
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void
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tls13_secrets_destroy(struct tls13_secrets *secrets)
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{
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if (secrets == NULL)
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return;
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/* you can never be too sure :) */
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freezero(secrets->zeros.data, secrets->zeros.len);
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freezero(secrets->empty_hash.data, secrets->empty_hash.len);
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freezero(secrets->extracted_early.data,
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secrets->extracted_early.len);
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freezero(secrets->binder_key.data,
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secrets->binder_key.len);
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freezero(secrets->client_early_traffic.data,
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secrets->client_early_traffic.len);
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freezero(secrets->early_exporter_master.data,
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secrets->early_exporter_master.len);
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freezero(secrets->derived_early.data,
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secrets->derived_early.len);
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freezero(secrets->extracted_handshake.data,
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secrets->extracted_handshake.len);
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freezero(secrets->client_handshake_traffic.data,
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secrets->client_handshake_traffic.len);
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freezero(secrets->server_handshake_traffic.data,
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secrets->server_handshake_traffic.len);
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freezero(secrets->derived_handshake.data,
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secrets->derived_handshake.len);
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freezero(secrets->extracted_master.data,
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secrets->extracted_master.len);
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freezero(secrets->client_application_traffic.data,
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secrets->client_application_traffic.len);
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freezero(secrets->server_application_traffic.data,
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secrets->server_application_traffic.len);
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freezero(secrets->exporter_master.data,
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secrets->exporter_master.len);
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freezero(secrets->resumption_master.data,
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secrets->resumption_master.len);
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freezero(secrets, sizeof(struct tls13_secrets));
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}
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/*
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* Allocate a set of secrets for a key schedule using
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* a size of hash_length from RFC 8446 section 7.1.
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*/
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struct tls13_secrets *
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tls13_secrets_create(const EVP_MD *digest, int resumption)
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{
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struct tls13_secrets *secrets = NULL;
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EVP_MD_CTX *mdctx = NULL;
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unsigned int mdlen;
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size_t hash_length;
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hash_length = EVP_MD_size(digest);
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if ((secrets = calloc(1, sizeof(struct tls13_secrets))) == NULL)
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goto err;
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if ((secrets->zeros.data = calloc(hash_length, sizeof(uint8_t))) ==
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NULL)
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goto err;
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secrets->zeros.len = hash_length;
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if ((secrets->empty_hash.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->empty_hash.len = hash_length;
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if ((secrets->extracted_early.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->extracted_early.len = hash_length;
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if ((secrets->binder_key.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->binder_key.len = hash_length;
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if ((secrets->client_early_traffic.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->client_early_traffic.len = hash_length;
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if ((secrets->early_exporter_master.data = malloc(hash_length)) ==
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NULL)
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goto err;
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secrets->early_exporter_master.len = hash_length;
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if ((secrets->derived_early.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->derived_early.len = hash_length;
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if ((secrets->extracted_handshake.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->extracted_handshake.len = hash_length;
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if ((secrets->client_handshake_traffic.data = malloc(hash_length))
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== NULL)
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goto err;
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secrets->client_handshake_traffic.len = hash_length;
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if ((secrets->server_handshake_traffic.data = malloc(hash_length))
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== NULL)
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goto err;
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secrets->server_handshake_traffic.len = hash_length;
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if ((secrets->derived_handshake.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->derived_handshake.len = hash_length;
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if ((secrets->extracted_master.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->extracted_master.len = hash_length;
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if ((secrets->client_application_traffic.data = malloc(hash_length)) ==
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NULL)
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goto err;
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secrets->client_application_traffic.len = hash_length;
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if ((secrets->server_application_traffic.data = malloc(hash_length)) ==
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NULL)
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goto err;
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secrets->server_application_traffic.len = hash_length;
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if ((secrets->exporter_master.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->exporter_master.len = hash_length;
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if ((secrets->resumption_master.data = malloc(hash_length)) == NULL)
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goto err;
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secrets->resumption_master.len = hash_length;
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/*
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* Calculate the hash of a zero-length string - this is needed during
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* the "derived" step for key extraction.
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*/
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if ((mdctx = EVP_MD_CTX_new()) == NULL)
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goto err;
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if (!EVP_DigestInit_ex(mdctx, digest, NULL))
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goto err;
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if (!EVP_DigestUpdate(mdctx, secrets->zeros.data, 0))
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goto err;
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if (!EVP_DigestFinal_ex(mdctx, secrets->empty_hash.data, &mdlen))
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goto err;
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EVP_MD_CTX_free(mdctx);
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mdctx = NULL;
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if (secrets->empty_hash.len != mdlen)
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goto err;
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secrets->digest = digest;
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secrets->resumption = resumption;
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secrets->init_done = 1;
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return secrets;
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err:
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tls13_secrets_destroy(secrets);
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EVP_MD_CTX_free(mdctx);
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return NULL;
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}
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int
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tls13_hkdf_expand_label(struct tls13_secret *out, const EVP_MD *digest,
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const struct tls13_secret *secret, const char *label,
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const struct tls13_secret *context)
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{
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const char tls13_plabel[] = "tls13 ";
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uint8_t *hkdf_label;
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size_t hkdf_label_len;
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CBB cbb, child;
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int ret;
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if (!CBB_init(&cbb, 256))
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return 0;
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if (!CBB_add_u16(&cbb, out->len))
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goto err;
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if (!CBB_add_u8_length_prefixed(&cbb, &child))
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goto err;
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if (!CBB_add_bytes(&child, tls13_plabel, strlen(tls13_plabel)))
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goto err;
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if (!CBB_add_bytes(&child, label, strlen(label)))
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goto err;
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if (!CBB_add_u8_length_prefixed(&cbb, &child))
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goto err;
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if (!CBB_add_bytes(&child, context->data, context->len))
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goto err;
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if (!CBB_finish(&cbb, &hkdf_label, &hkdf_label_len))
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goto err;
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ret = HKDF_expand(out->data, out->len, digest, secret->data,
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secret->len, hkdf_label, hkdf_label_len);
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free(hkdf_label);
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return(ret);
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err:
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CBB_cleanup(&cbb);
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return(0);
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}
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static int
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tls13_derive_secret(struct tls13_secret *out, const EVP_MD *digest,
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const struct tls13_secret *secret, const char *label,
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const struct tls13_secret *context)
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{
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return tls13_hkdf_expand_label(out, digest, secret, label, context);
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}
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int
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tls13_derive_early_secrets(struct tls13_secrets *secrets,
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uint8_t *psk, size_t psk_len, const struct tls13_secret *context)
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{
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if (!secrets->init_done || secrets->early_done)
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return 0;
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if (!HKDF_extract(secrets->extracted_early.data,
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&secrets->extracted_early.len, secrets->digest, psk, psk_len,
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secrets->zeros.data, secrets->zeros.len))
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return 0;
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if (secrets->extracted_early.len != secrets->zeros.len)
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return 0;
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if (!tls13_derive_secret(&secrets->binder_key, secrets->digest,
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&secrets->extracted_early,
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secrets->resumption ? "res binder" : "ext binder",
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&secrets->empty_hash))
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return 0;
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if (!tls13_derive_secret(&secrets->client_early_traffic,
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secrets->digest, &secrets->extracted_early, "c e traffic",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->early_exporter_master,
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secrets->digest, &secrets->extracted_early, "e exp master",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->derived_early,
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secrets->digest, &secrets->extracted_early, "derived",
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&secrets->empty_hash))
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return 0;
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/* RFC 8446 recommends */
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if (!secrets->insecure)
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explicit_bzero(secrets->extracted_early.data,
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secrets->extracted_early.len);
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secrets->early_done = 1;
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return 1;
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}
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int
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tls13_derive_handshake_secrets(struct tls13_secrets *secrets,
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const uint8_t *ecdhe, size_t ecdhe_len,
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const struct tls13_secret *context)
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{
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if (!secrets->init_done || !secrets->early_done ||
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secrets->handshake_done)
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return 0;
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if (!HKDF_extract(secrets->extracted_handshake.data,
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&secrets->extracted_handshake.len, secrets->digest,
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ecdhe, ecdhe_len, secrets->derived_early.data,
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secrets->derived_early.len))
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return 0;
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if (secrets->extracted_handshake.len != secrets->zeros.len)
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return 0;
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/* XXX */
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if (!secrets->insecure)
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explicit_bzero(secrets->derived_early.data,
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secrets->derived_early.len);
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if (!tls13_derive_secret(&secrets->client_handshake_traffic,
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secrets->digest, &secrets->extracted_handshake, "c hs traffic",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->server_handshake_traffic,
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secrets->digest, &secrets->extracted_handshake, "s hs traffic",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->derived_handshake,
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secrets->digest, &secrets->extracted_handshake, "derived",
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&secrets->empty_hash))
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return 0;
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/* RFC 8446 recommends */
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if (!secrets->insecure)
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explicit_bzero(secrets->extracted_handshake.data,
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secrets->extracted_handshake.len);
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secrets->handshake_done = 1;
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return 1;
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}
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int
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tls13_derive_application_secrets(struct tls13_secrets *secrets,
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const struct tls13_secret *context)
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{
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if (!secrets->init_done || !secrets->early_done ||
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!secrets->handshake_done || secrets->schedule_done)
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return 0;
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if (!HKDF_extract(secrets->extracted_master.data,
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&secrets->extracted_master.len, secrets->digest,
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secrets->zeros.data, secrets->zeros.len,
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secrets->derived_handshake.data, secrets->derived_handshake.len))
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return 0;
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if (secrets->extracted_master.len != secrets->zeros.len)
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return 0;
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/* XXX */
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if (!secrets->insecure)
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explicit_bzero(secrets->derived_handshake.data,
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secrets->derived_handshake.len);
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if (!tls13_derive_secret(&secrets->client_application_traffic,
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secrets->digest, &secrets->extracted_master, "c ap traffic",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->server_application_traffic,
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secrets->digest, &secrets->extracted_master, "s ap traffic",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->exporter_master,
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secrets->digest, &secrets->extracted_master, "exp master",
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context))
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return 0;
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if (!tls13_derive_secret(&secrets->resumption_master,
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secrets->digest, &secrets->extracted_master, "res master",
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context))
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return 0;
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/* RFC 8446 recommends */
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if (!secrets->insecure)
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explicit_bzero(secrets->extracted_master.data,
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secrets->extracted_master.len);
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secrets->schedule_done = 1;
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return 1;
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}
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int
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tls13_update_client_traffic_secret(struct tls13_secrets *secrets)
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{
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struct tls13_secret context = { .data = "", .len = 0 };
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if (!secrets->init_done || !secrets->early_done ||
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!secrets->handshake_done || !secrets->schedule_done)
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return 0;
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return tls13_hkdf_expand_label(&secrets->client_application_traffic,
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secrets->digest, &secrets->client_application_traffic,
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"traffic upd", &context);
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}
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int
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tls13_update_server_traffic_secret(struct tls13_secrets *secrets)
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{
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struct tls13_secret context = { .data = "", .len = 0 };
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if (!secrets->init_done || !secrets->early_done ||
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!secrets->handshake_done || !secrets->schedule_done)
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return 0;
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return tls13_hkdf_expand_label(&secrets->server_application_traffic,
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secrets->digest, &secrets->server_application_traffic,
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"traffic upd", &context);
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}
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