1 /* 2 * Copyright 2023 The OpenSSL Project Authors. All Rights Reserved. 3 * 4 * Licensed under the Apache License 2.0 (the "License"). You may not use 5 * this file except in compliance with the License. You can obtain a copy 6 * in the file LICENSE in the source distribution or at 7 * https://www.openssl.org/source/license.html 8 */ 9 #include "internal/quic_srt_gen.h" 10 #include <openssl/core_names.h> 11 #include <openssl/evp.h> 12 13 struct quic_srt_gen_st { 14 EVP_MAC *mac; 15 EVP_MAC_CTX *mac_ctx; 16 }; 17 18 /* 19 * Simple HMAC-SHA256-based stateless reset token generator. 20 */ 21 22 QUIC_SRT_GEN *ossl_quic_srt_gen_new(OSSL_LIB_CTX *libctx, const char *propq, 23 const unsigned char *key, size_t key_len) 24 { 25 QUIC_SRT_GEN *srt_gen; 26 OSSL_PARAM params[3], *p = params; 27 28 if ((srt_gen = OPENSSL_zalloc(sizeof(*srt_gen))) == NULL) 29 return NULL; 30 31 if ((srt_gen->mac = EVP_MAC_fetch(libctx, "HMAC", propq)) == NULL) 32 goto err; 33 34 if ((srt_gen->mac_ctx = EVP_MAC_CTX_new(srt_gen->mac)) == NULL) 35 goto err; 36 37 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_DIGEST, "SHA256", 7); 38 if (propq != NULL) 39 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_PROPERTIES, 40 (char *)propq, 0); 41 *p++ = OSSL_PARAM_construct_end(); 42 43 if (!EVP_MAC_init(srt_gen->mac_ctx, key, key_len, params)) 44 goto err; 45 46 return srt_gen; 47 48 err: 49 ossl_quic_srt_gen_free(srt_gen); 50 return NULL; 51 } 52 53 void ossl_quic_srt_gen_free(QUIC_SRT_GEN *srt_gen) 54 { 55 if (srt_gen == NULL) 56 return; 57 58 EVP_MAC_CTX_free(srt_gen->mac_ctx); 59 EVP_MAC_free(srt_gen->mac); 60 OPENSSL_free(srt_gen); 61 } 62 63 int ossl_quic_srt_gen_calculate_token(QUIC_SRT_GEN *srt_gen, 64 const QUIC_CONN_ID *dcid, 65 QUIC_STATELESS_RESET_TOKEN *token) 66 { 67 size_t outl = 0; 68 unsigned char mac[SHA256_DIGEST_LENGTH]; 69 70 if (!EVP_MAC_init(srt_gen->mac_ctx, NULL, 0, NULL)) 71 return 0; 72 73 if (!EVP_MAC_update(srt_gen->mac_ctx, (const unsigned char *)dcid->id, 74 dcid->id_len)) 75 return 0; 76 77 if (!EVP_MAC_final(srt_gen->mac_ctx, mac, &outl, sizeof(mac)) 78 || outl != sizeof(mac)) 79 return 0; 80 81 assert(sizeof(mac) >= sizeof(token->token)); 82 memcpy(token->token, mac, sizeof(token->token)); 83 return 1; 84 } 85