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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*/
#include "tomcrypt.h"
/**
@file der_decode_subject_public_key_info.c
ASN.1 DER, encode a Subject Public Key structure --nmav
*/
#ifdef LTC_DER
/* AlgorithmIdentifier := SEQUENCE {
* algorithm OBJECT IDENTIFIER,
* parameters ANY DEFINED BY algorithm
* }
*
* SubjectPublicKeyInfo := SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING
* }
*/
/**
Decode a subject public key info
@param in The input buffer
@param inlen The length of the input buffer
@param algorithm One out of the enum #public_key_algorithms
@param public_key The buffer for the public key
@param public_key_len [in/out] The length of the public key buffer and the written length
@param parameters_type The parameters' type out of the enum ltc_asn1_type
@param parameters The parameters to include
@param parameters_len The number of parameters to include
@return CRYPT_OK on success
*/
int der_decode_subject_public_key_info(const unsigned char *in, unsigned long inlen,
unsigned int algorithm, void* public_key, unsigned long* public_key_len,
unsigned long parameters_type, ltc_asn1_list* parameters, unsigned long parameters_len)
{
int err;
unsigned long len;
oid_st oid;
unsigned char *tmpbuf;
unsigned long tmpoid[16];
ltc_asn1_list alg_id[2];
ltc_asn1_list subject_pubkey[2];
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(inlen != 0);
LTC_ARGCHK(public_key_len != NULL);
err = pk_get_oid(algorithm, &oid);
if (err != CRYPT_OK) {
return err;
}
/* see if the OpenSSL DER format RSA public key will work */
tmpbuf = XCALLOC(1, inlen);
if (tmpbuf == NULL) {
err = CRYPT_MEM;
goto LBL_ERR;
}
/* this includes the internal hash ID and optional params (NULL in this case) */
LTC_SET_ASN1(alg_id, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, sizeof(tmpoid)/sizeof(tmpoid[0]));
LTC_SET_ASN1(alg_id, 1, (ltc_asn1_type)parameters_type, parameters, parameters_len);
/* the actual format of the SSL DER key is odd, it stores a RSAPublicKey
* in a **BIT** string ... so we have to extract it then proceed to convert bit to octet
*/
LTC_SET_ASN1(subject_pubkey, 0, LTC_ASN1_SEQUENCE, alg_id, 2);
LTC_SET_ASN1(subject_pubkey, 1, LTC_ASN1_RAW_BIT_STRING, tmpbuf, inlen*8U);
err=der_decode_sequence(in, inlen, subject_pubkey, 2UL);
if (err != CRYPT_OK) {
goto LBL_ERR;
}
if ((alg_id[0].size != oid.OIDlen) ||
XMEMCMP(oid.OID, alg_id[0].data, oid.OIDlen * sizeof(oid.OID[0]))) {
/* OID mismatch */
err = CRYPT_PK_INVALID_TYPE;
goto LBL_ERR;
}
len = subject_pubkey[1].size/8;
if (*public_key_len > len) {
XMEMCPY(public_key, subject_pubkey[1].data, len);
*public_key_len = len;
} else {
*public_key_len = len;
err = CRYPT_BUFFER_OVERFLOW;
goto LBL_ERR;
}
err = CRYPT_OK;
LBL_ERR:
XFREE(tmpbuf);
return err;
}
#endif
/* ref: $Format:%D$ */
/* git commit: $Format:%H$ */
/* commit time: $Format:%ai$ */
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