1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5 /**
6 @file ecc_ssh_ecdsa_encode_name.c
7 Curve/OID to SSH+ECDSA name string mapping per RFC5656
8 Russ Williams
9 */
10
11 #ifdef LTC_SSH
12
13 /**
14 Curve/OID to SSH+ECDSA name string mapping
15 @param buffer [out] The destination for the name
16 @param buflen [in/out] The max size and resulting size (including terminator) of the name
17 @param key A public or private ECC key
18 @return CRYPT_OK if successful
19 */
ecc_ssh_ecdsa_encode_name(char * buffer,unsigned long * buflen,const ecc_key * key)20 int ecc_ssh_ecdsa_encode_name(char *buffer, unsigned long *buflen, const ecc_key *key)
21 {
22 char oidstr[64] = {0};
23 unsigned long oidlen = sizeof(oidstr);
24 int err, size = 0;
25
26 LTC_ARGCHK(buffer != NULL);
27 LTC_ARGCHK(buflen != NULL);
28 LTC_ARGCHK(key != NULL);
29
30 /* Get the OID of the curve */
31 if ((err = ecc_get_oid_str(oidstr, &oidlen, key)) != CRYPT_OK) goto error;
32
33 /* Check for three named curves: nistp256, nistp384, nistp521 */
34 if (XSTRCMP("1.2.840.10045.3.1.7", oidstr) == 0) {
35 /* nistp256 - secp256r1 - OID 1.2.840.10045.3.1.7 */
36 size = snprintf(buffer, *buflen, "ecdsa-sha2-nistp256");
37 }
38 else if (XSTRCMP("1.3.132.0.34", oidstr) == 0) {
39 /* nistp384 - secp384r1 - OID 1.3.132.0.34 */
40 size = snprintf(buffer, *buflen, "ecdsa-sha2-nistp384");
41 }
42 else if (XSTRCMP("1.3.132.0.35", oidstr) == 0) {
43 /* nistp521 - secp521r1 - OID 1.3.132.0.35 */
44 size = snprintf(buffer, *buflen, "ecdsa-sha2-nistp521");
45 } else {
46 /* Otherwise we use the OID... */
47 size = snprintf(buffer, *buflen, "ecdsa-sha2-%s", oidstr);
48 }
49
50 /* snprintf returns a negative value on error
51 * or the size that would have been written, but limits to buflen-1 chars plus terminator */
52 if (size < 0) {
53 err = CRYPT_ERROR;
54 } else if ((unsigned)size >= *buflen) {
55 err = CRYPT_BUFFER_OVERFLOW;
56 } else {
57 err = CRYPT_OK;
58 }
59 *buflen = size + 1; /* the string length + NUL byte */
60
61 error:
62 return err;
63 }
64
65 #endif
66