1 // Copyright 2024 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not
4 // use this file except in compliance with the License. You may obtain a copy of
5 // the License at
6 //
7 // https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
12 // License for the specific language governing permissions and limitations under
13 // the License.
14
15 // This is a configurable, multi-algorithm implementation of signature
16 // operations using boringssl.
17
18 #include <stdint.h>
19 #include <stdio.h>
20
21 #include "dice/boringssl_ecdsa_utils.h"
22 #include "dice/config/cose_key_config.h"
23 #include "dice/dice.h"
24 #include "dice/ops.h"
25 #include "openssl/curve25519.h"
26
27 #if DICE_PRIVATE_KEY_SEED_SIZE != 32
28 #error "Private key seed is expected to be 32 bytes."
29 #endif
30 #if DICE_PUBLIC_KEY_BUFFER_SIZE != 96
31 #error "Multialg needs 96 bytes to for the public key (P-384)"
32 #endif
33 #if DICE_PRIVATE_KEY_BUFFER_SIZE != 64
34 #error "Multialg needs 64 bytes for the private key (Ed25519)"
35 #endif
36 #if DICE_SIGNATURE_BUFFER_SIZE != 96
37 #error "Multialg needs 96 bytes to store the signature (P-384)"
38 #endif
39
DiceGetKeyParam(void * context,DicePrincipal principal,DiceKeyParam * key_param)40 DiceResult DiceGetKeyParam(void* context, DicePrincipal principal,
41 DiceKeyParam* key_param) {
42 DiceKeyAlgorithm alg;
43 DiceResult result = DiceGetKeyAlgorithm(context, principal, &alg);
44 if (result != kDiceResultOk) {
45 return result;
46 }
47 switch (alg) {
48 case kDiceKeyAlgorithmEd25519:
49 key_param->public_key_size = 32;
50 key_param->signature_size = 64;
51
52 key_param->cose_key_type = kCoseKeyKtyOkp;
53 key_param->cose_key_algorithm = kCoseAlgEdDsa;
54 key_param->cose_key_curve = kCoseCrvEd25519;
55 return kDiceResultOk;
56 case kDiceKeyAlgorithmP256:
57 key_param->public_key_size = 64;
58 key_param->signature_size = 64;
59
60 key_param->cose_key_type = kCoseKeyKtyEc2;
61 key_param->cose_key_algorithm = kCoseAlgEs256;
62 key_param->cose_key_curve = kCoseCrvP256;
63 return kDiceResultOk;
64 case kDiceKeyAlgorithmP384:
65 key_param->public_key_size = 96;
66 key_param->signature_size = 96;
67
68 key_param->cose_key_type = kCoseKeyKtyEc2;
69 key_param->cose_key_algorithm = kCoseAlgEs384;
70 key_param->cose_key_curve = kCoseCrvP384;
71 return kDiceResultOk;
72 }
73 return kDiceResultPlatformError;
74 }
75
DiceKeypairFromSeed(void * context,DicePrincipal principal,const uint8_t seed[DICE_PRIVATE_KEY_SEED_SIZE],uint8_t public_key[DICE_PUBLIC_KEY_BUFFER_SIZE],uint8_t private_key[DICE_PRIVATE_KEY_BUFFER_SIZE])76 DiceResult DiceKeypairFromSeed(
77 void* context, DicePrincipal principal,
78 const uint8_t seed[DICE_PRIVATE_KEY_SEED_SIZE],
79 uint8_t public_key[DICE_PUBLIC_KEY_BUFFER_SIZE],
80 uint8_t private_key[DICE_PRIVATE_KEY_BUFFER_SIZE]) {
81 DiceKeyAlgorithm alg;
82 DiceResult result = DiceGetKeyAlgorithm(context, principal, &alg);
83 if (result != kDiceResultOk) {
84 return result;
85 }
86 switch (alg) {
87 case kDiceKeyAlgorithmEd25519:
88 ED25519_keypair_from_seed(public_key, private_key, seed);
89 return kDiceResultOk;
90 case kDiceKeyAlgorithmP256:
91 if (1 == P256KeypairFromSeed(public_key, private_key, seed)) {
92 return kDiceResultOk;
93 }
94 break;
95 case kDiceKeyAlgorithmP384:
96 if (1 == P384KeypairFromSeed(public_key, private_key, seed)) {
97 return kDiceResultOk;
98 }
99 break;
100 }
101 return kDiceResultPlatformError;
102 }
103
DiceSign(void * context,const uint8_t * message,size_t message_size,const uint8_t private_key[DICE_PRIVATE_KEY_BUFFER_SIZE],uint8_t signature[DICE_SIGNATURE_BUFFER_SIZE])104 DiceResult DiceSign(void* context, const uint8_t* message, size_t message_size,
105 const uint8_t private_key[DICE_PRIVATE_KEY_BUFFER_SIZE],
106 uint8_t signature[DICE_SIGNATURE_BUFFER_SIZE]) {
107 DiceKeyAlgorithm alg;
108 DiceResult result =
109 DiceGetKeyAlgorithm(context, kDicePrincipalAuthority, &alg);
110 if (result != kDiceResultOk) {
111 return result;
112 }
113 switch (alg) {
114 case kDiceKeyAlgorithmEd25519:
115 if (1 == ED25519_sign(signature, message, message_size, private_key)) {
116 return kDiceResultOk;
117 }
118 break;
119 case kDiceKeyAlgorithmP256:
120 if (1 == P256Sign(signature, message, message_size, private_key)) {
121 return kDiceResultOk;
122 }
123 break;
124 case kDiceKeyAlgorithmP384:
125 if (1 == P384Sign(signature, message, message_size, private_key)) {
126 return kDiceResultOk;
127 }
128 break;
129 }
130 return kDiceResultPlatformError;
131 }
132
DiceVerify(void * context,const uint8_t * message,size_t message_size,const uint8_t signature[DICE_SIGNATURE_BUFFER_SIZE],const uint8_t public_key[DICE_PUBLIC_KEY_BUFFER_SIZE])133 DiceResult DiceVerify(void* context, const uint8_t* message,
134 size_t message_size,
135 const uint8_t signature[DICE_SIGNATURE_BUFFER_SIZE],
136 const uint8_t public_key[DICE_PUBLIC_KEY_BUFFER_SIZE]) {
137 DiceKeyAlgorithm alg;
138 DiceResult result =
139 DiceGetKeyAlgorithm(context, kDicePrincipalAuthority, &alg);
140 if (result != kDiceResultOk) {
141 return result;
142 }
143 switch (alg) {
144 case kDiceKeyAlgorithmEd25519:
145 if (1 == ED25519_verify(message, message_size, signature, public_key)) {
146 return kDiceResultOk;
147 }
148 break;
149 case kDiceKeyAlgorithmP256:
150 if (1 == P256Verify(message, message_size, signature, public_key)) {
151 return kDiceResultOk;
152 }
153 break;
154 case kDiceKeyAlgorithmP384:
155 if (1 == P384Verify(message, message_size, signature, public_key)) {
156 return kDiceResultOk;
157 }
158 break;
159 }
160 return kDiceResultPlatformError;
161 }
162