1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 */
9 #include "tomcrypt.h"
10
11 /**
12 @file dsa_import.c
13 DSA implementation, import a DSA key, Tom St Denis
14 */
15
16 #ifdef LTC_MDSA
17
18 /**
19 Import a DSA key
20 @param in The binary packet to import from
21 @param inlen The length of the binary packet
22 @param key [out] Where to store the imported key
23 @return CRYPT_OK if successful, upon error this function will free all allocated memory
24 */
dsa_import(const unsigned char * in,unsigned long inlen,dsa_key * key)25 int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
26 {
27 int err, stat;
28 unsigned long zero = 0;
29 unsigned char* tmpbuf = NULL;
30 unsigned char flags[1];
31
32 LTC_ARGCHK(in != NULL);
33 LTC_ARGCHK(key != NULL);
34 LTC_ARGCHK(ltc_mp.name != NULL);
35
36 /* init key */
37 if (mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL) != CRYPT_OK) {
38 return CRYPT_MEM;
39 }
40
41 /* try to match the old libtomcrypt format */
42 err = der_decode_sequence_multi(in, inlen, LTC_ASN1_BIT_STRING, 1UL, flags,
43 LTC_ASN1_EOL, 0UL, NULL);
44
45 if (err == CRYPT_OK || err == CRYPT_INPUT_TOO_LONG) {
46 /* private key */
47 if (flags[0] == 1) {
48 if ((err = der_decode_sequence_multi(in, inlen,
49 LTC_ASN1_BIT_STRING, 1UL, flags,
50 LTC_ASN1_INTEGER, 1UL, key->g,
51 LTC_ASN1_INTEGER, 1UL, key->p,
52 LTC_ASN1_INTEGER, 1UL, key->q,
53 LTC_ASN1_INTEGER, 1UL, key->y,
54 LTC_ASN1_INTEGER, 1UL, key->x,
55 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
56 goto LBL_ERR;
57 }
58 key->type = PK_PRIVATE;
59 goto LBL_OK;
60 }
61 /* public key */
62 else if (flags[0] == 0) {
63 if ((err = der_decode_sequence_multi(in, inlen,
64 LTC_ASN1_BIT_STRING, 1UL, flags,
65 LTC_ASN1_INTEGER, 1UL, key->g,
66 LTC_ASN1_INTEGER, 1UL, key->p,
67 LTC_ASN1_INTEGER, 1UL, key->q,
68 LTC_ASN1_INTEGER, 1UL, key->y,
69 LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
70 goto LBL_ERR;
71 }
72 key->type = PK_PUBLIC;
73 goto LBL_OK;
74 }
75 else {
76 err = CRYPT_INVALID_PACKET;
77 goto LBL_ERR;
78 }
79 }
80 /* get key type */
81 if ((err = der_decode_sequence_multi(in, inlen,
82 LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
83 LTC_ASN1_INTEGER, 1UL, key->p,
84 LTC_ASN1_INTEGER, 1UL, key->q,
85 LTC_ASN1_INTEGER, 1UL, key->g,
86 LTC_ASN1_INTEGER, 1UL, key->y,
87 LTC_ASN1_INTEGER, 1UL, key->x,
88 LTC_ASN1_EOL, 0UL, NULL)) == CRYPT_OK) {
89
90 key->type = PK_PRIVATE;
91 } else { /* public */
92 ltc_asn1_list params[3];
93 unsigned long tmpbuf_len = inlen;
94
95 LTC_SET_ASN1(params, 0, LTC_ASN1_INTEGER, key->p, 1UL);
96 LTC_SET_ASN1(params, 1, LTC_ASN1_INTEGER, key->q, 1UL);
97 LTC_SET_ASN1(params, 2, LTC_ASN1_INTEGER, key->g, 1UL);
98
99 tmpbuf = XCALLOC(1, tmpbuf_len);
100 if (tmpbuf == NULL) {
101 err = CRYPT_MEM;
102 goto LBL_ERR;
103 }
104
105 err = der_decode_subject_public_key_info(in, inlen, PKA_DSA,
106 tmpbuf, &tmpbuf_len,
107 LTC_ASN1_SEQUENCE, params, 3);
108 if (err != CRYPT_OK) {
109 XFREE(tmpbuf);
110 goto LBL_ERR;
111 }
112
113 if ((err=der_decode_integer(tmpbuf, tmpbuf_len, key->y)) != CRYPT_OK) {
114 XFREE(tmpbuf);
115 goto LBL_ERR;
116 }
117
118 XFREE(tmpbuf);
119 key->type = PK_PUBLIC;
120 }
121
122 LBL_OK:
123 key->qord = mp_unsigned_bin_size(key->q);
124
125 /* quick p, q, g validation, without primality testing */
126 if ((err = dsa_int_validate_pqg(key, &stat)) != CRYPT_OK) {
127 goto LBL_ERR;
128 }
129 if (stat == 0) {
130 err = CRYPT_INVALID_PACKET;
131 goto LBL_ERR;
132 }
133 /* validate x, y */
134 if ((err = dsa_int_validate_xy(key, &stat)) != CRYPT_OK) {
135 goto LBL_ERR;
136 }
137 if (stat == 0) {
138 err = CRYPT_INVALID_PACKET;
139 goto LBL_ERR;
140 }
141
142 return CRYPT_OK;
143 LBL_ERR:
144 dsa_free(key);
145 return err;
146 }
147
148 #endif
149
150 /* ref: $Format:%D$ */
151 /* git commit: $Format:%H$ */
152 /* commit time: $Format:%ai$ */
153