1 /*
2 * QEMU Crypto hmac algorithms
3 *
4 * Copyright (c) 2021 Red Hat, Inc.
5 *
6 * Derived from hmac-gcrypt.c:
7 *
8 * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
9 *
10 * This work is licensed under the terms of the GNU GPL, version 2 or
11 * (at your option) any later version. See the COPYING file in the
12 * top-level directory.
13 *
14 */
15
16 #include "qemu/osdep.h"
17 #include <gnutls/crypto.h>
18
19 #include "qapi/error.h"
20 #include "crypto/hmac.h"
21 #include "hmacpriv.h"
22
23 static int qcrypto_hmac_alg_map[QCRYPTO_HASH_ALG__MAX] = {
24 [QCRYPTO_HASH_ALG_MD5] = GNUTLS_MAC_MD5,
25 [QCRYPTO_HASH_ALG_SHA1] = GNUTLS_MAC_SHA1,
26 [QCRYPTO_HASH_ALG_SHA224] = GNUTLS_MAC_SHA224,
27 [QCRYPTO_HASH_ALG_SHA256] = GNUTLS_MAC_SHA256,
28 [QCRYPTO_HASH_ALG_SHA384] = GNUTLS_MAC_SHA384,
29 [QCRYPTO_HASH_ALG_SHA512] = GNUTLS_MAC_SHA512,
30 [QCRYPTO_HASH_ALG_RIPEMD160] = GNUTLS_MAC_RMD160,
31 };
32
33 typedef struct QCryptoHmacGnutls QCryptoHmacGnutls;
34 struct QCryptoHmacGnutls {
35 gnutls_hmac_hd_t handle;
36 };
37
qcrypto_hmac_supports(QCryptoHashAlgorithm alg)38 bool qcrypto_hmac_supports(QCryptoHashAlgorithm alg)
39 {
40 size_t i;
41 const gnutls_digest_algorithm_t *algs;
42 if (alg >= G_N_ELEMENTS(qcrypto_hmac_alg_map) ||
43 qcrypto_hmac_alg_map[alg] == GNUTLS_DIG_UNKNOWN) {
44 return false;
45 }
46 algs = gnutls_digest_list();
47 for (i = 0; algs[i] != GNUTLS_DIG_UNKNOWN; i++) {
48 if (algs[i] == qcrypto_hmac_alg_map[alg]) {
49 return true;
50 }
51 }
52 return false;
53 }
54
qcrypto_hmac_ctx_new(QCryptoHashAlgorithm alg,const uint8_t * key,size_t nkey,Error ** errp)55 void *qcrypto_hmac_ctx_new(QCryptoHashAlgorithm alg,
56 const uint8_t *key, size_t nkey,
57 Error **errp)
58 {
59 QCryptoHmacGnutls *ctx;
60 int err;
61
62 if (!qcrypto_hmac_supports(alg)) {
63 error_setg(errp, "Unsupported hmac algorithm %s",
64 QCryptoHashAlgorithm_str(alg));
65 return NULL;
66 }
67
68 ctx = g_new0(QCryptoHmacGnutls, 1);
69
70 err = gnutls_hmac_init(&ctx->handle,
71 qcrypto_hmac_alg_map[alg],
72 (const void *)key, nkey);
73 if (err != 0) {
74 error_setg(errp, "Cannot initialize hmac: %s",
75 gnutls_strerror(err));
76 goto error;
77 }
78
79 return ctx;
80
81 error:
82 g_free(ctx);
83 return NULL;
84 }
85
86 static void
qcrypto_gnutls_hmac_ctx_free(QCryptoHmac * hmac)87 qcrypto_gnutls_hmac_ctx_free(QCryptoHmac *hmac)
88 {
89 QCryptoHmacGnutls *ctx;
90
91 ctx = hmac->opaque;
92 gnutls_hmac_deinit(ctx->handle, NULL);
93
94 g_free(ctx);
95 }
96
97 static int
qcrypto_gnutls_hmac_bytesv(QCryptoHmac * hmac,const struct iovec * iov,size_t niov,uint8_t ** result,size_t * resultlen,Error ** errp)98 qcrypto_gnutls_hmac_bytesv(QCryptoHmac *hmac,
99 const struct iovec *iov,
100 size_t niov,
101 uint8_t **result,
102 size_t *resultlen,
103 Error **errp)
104 {
105 QCryptoHmacGnutls *ctx;
106 uint32_t ret;
107 int i;
108
109 ctx = hmac->opaque;
110
111 for (i = 0; i < niov; i++) {
112 gnutls_hmac(ctx->handle, iov[i].iov_base, iov[i].iov_len);
113 }
114
115 ret = gnutls_hmac_get_len(qcrypto_hmac_alg_map[hmac->alg]);
116 if (ret <= 0) {
117 error_setg(errp, "Unable to get hmac length: %s",
118 gnutls_strerror(ret));
119 return -1;
120 }
121
122 if (*resultlen == 0) {
123 *resultlen = ret;
124 *result = g_new0(uint8_t, *resultlen);
125 } else if (*resultlen != ret) {
126 error_setg(errp, "Result buffer size %zu is smaller than hmac %d",
127 *resultlen, ret);
128 return -1;
129 }
130
131 gnutls_hmac_output(ctx->handle, *result);
132
133 return 0;
134 }
135
136 QCryptoHmacDriver qcrypto_hmac_lib_driver = {
137 .hmac_bytesv = qcrypto_gnutls_hmac_bytesv,
138 .hmac_free = qcrypto_gnutls_hmac_ctx_free,
139 };
140