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
ossl_quic_srt_gen_new(OSSL_LIB_CTX * libctx,const char * propq,const unsigned char * key,size_t key_len)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
ossl_quic_srt_gen_free(QUIC_SRT_GEN * srt_gen)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
ossl_quic_srt_gen_calculate_token(QUIC_SRT_GEN * srt_gen,const QUIC_CONN_ID * dcid,QUIC_STATELESS_RESET_TOKEN * token)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
