1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file x509_decode_subject_public_key_info.c
14 ASN.1 DER/X.509, encode a SubjectPublicKeyInfo structure --nmav
15 */
16
17 #ifdef LTC_DER
18
19 /* AlgorithmIdentifier := SEQUENCE {
20 * algorithm OBJECT IDENTIFIER,
21 * parameters ANY DEFINED BY algorithm
22 * }
23 *
24 * SubjectPublicKeyInfo := SEQUENCE {
25 * algorithm AlgorithmIdentifier,
26 * subjectPublicKey BIT STRING
27 * }
28 */
29 /**
30 Decode a SubjectPublicKeyInfo
31 @param in The input buffer
32 @param inlen The length of the input buffer
33 @param algorithm One out of the enum #public_key_algorithms
34 @param public_key The buffer for the public key
35 @param public_key_len [in/out] The length of the public key buffer and the written length
36 @param parameters_type The parameters' type out of the enum ltc_asn1_type
37 @param parameters The parameters to include
38 @param parameters_len [in/out] The number of parameters to include
39 @return CRYPT_OK on success
40 */
x509_decode_subject_public_key_info(const unsigned char * in,unsigned long inlen,unsigned int algorithm,void * public_key,unsigned long * public_key_len,ltc_asn1_type parameters_type,ltc_asn1_list * parameters,unsigned long * parameters_len)41 int x509_decode_subject_public_key_info(const unsigned char *in, unsigned long inlen,
42 unsigned int algorithm, void* public_key, unsigned long* public_key_len,
43 ltc_asn1_type parameters_type, ltc_asn1_list* parameters, unsigned long *parameters_len)
44 {
45 int err;
46 unsigned long len, alg_id_num, tmplen;
47 const char* oid;
48 unsigned char *tmpbuf;
49 unsigned long tmpoid[16];
50 unsigned long *_parameters_len;
51 ltc_asn1_list alg_id[2];
52 ltc_asn1_list subject_pubkey[2];
53
54 LTC_ARGCHK(in != NULL);
55 LTC_ARGCHK(inlen != 0);
56 LTC_ARGCHK(public_key_len != NULL);
57
58 if (parameters_type != LTC_ASN1_EOL) {
59 if ((parameters == NULL) || (parameters_len == NULL)) {
60 tmplen = 0;
61 _parameters_len = &tmplen;
62 } else {
63 _parameters_len = parameters_len;
64 }
65 }
66
67 err = pk_get_oid(algorithm, &oid);
68 if (err != CRYPT_OK) {
69 return err;
70 }
71
72 /* see if the OpenSSL DER format RSA public key will work */
73 tmpbuf = XCALLOC(1, inlen);
74 if (tmpbuf == NULL) {
75 err = CRYPT_MEM;
76 goto LBL_ERR;
77 }
78
79 /* this includes the internal hash ID and optional params (NULL in this case) */
80 LTC_SET_ASN1(alg_id, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, sizeof(tmpoid)/sizeof(tmpoid[0]));
81 if (parameters_type == LTC_ASN1_EOL) {
82 alg_id_num = 1;
83 } else {
84 LTC_SET_ASN1(alg_id, 1, parameters_type, parameters, *_parameters_len);
85 alg_id_num = 2;
86 }
87
88 /* the actual format of the SSL DER key is odd, it stores a RSAPublicKey
89 * in a **BIT** string ... so we have to extract it then proceed to convert bit to octet
90 */
91 LTC_SET_ASN1(subject_pubkey, 0, LTC_ASN1_SEQUENCE, alg_id, alg_id_num);
92 LTC_SET_ASN1(subject_pubkey, 1, LTC_ASN1_RAW_BIT_STRING, tmpbuf, inlen*8U);
93
94 err=der_decode_sequence(in, inlen, subject_pubkey, 2UL);
95 if (err != CRYPT_OK) {
96 goto LBL_ERR;
97 }
98 if (parameters_type != LTC_ASN1_EOL) {
99 *_parameters_len = alg_id[1].size;
100 }
101
102 if ((err = pk_oid_cmp_with_asn1(oid, &alg_id[0])) != CRYPT_OK) {
103 /* OID mismatch */
104 goto LBL_ERR;
105 }
106
107 len = subject_pubkey[1].size/8;
108 if (*public_key_len >= len) {
109 XMEMCPY(public_key, subject_pubkey[1].data, len);
110 *public_key_len = len;
111 } else {
112 *public_key_len = len;
113 err = CRYPT_BUFFER_OVERFLOW;
114 goto LBL_ERR;
115 }
116
117 err = CRYPT_OK;
118
119 LBL_ERR:
120
121 XFREE(tmpbuf);
122
123 return err;
124 }
125
126 #endif
127
128 /* ref: $Format:%D$ */
129 /* git commit: $Format:%H$ */
130 /* commit time: $Format:%ai$ */
131