pkcs8.c

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#include "includes.h"

#include "common.h"
#include "asn1.h"
#include "bignum.h"
#include "rsa.h"
#include "pkcs5.h"
#include "pkcs8.h"


struct crypto_private_key * pkcs8_key_import(const u8 *buf, size_t len)
{
        struct asn1_hdr hdr;
        const u8 *pos, *end;
        struct bignum *zero;
        struct asn1_oid oid;
        char obuf[80];

        /* PKCS #8, Chapter 6 */

        /* PrivateKeyInfo ::= SEQUENCE */
        if (asn1_get_next(buf, len, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Does not start with PKCS #8 "
                           "header (SEQUENCE); assume PKCS #8 not used");
                return NULL;
        }
        pos = hdr.payload;
        end = pos + hdr.length;

        /* version Version (Version ::= INTEGER) */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL || hdr.tag != ASN1_TAG_INTEGER) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected INTEGER - found "
                           "class %d tag 0x%x; assume PKCS #8 not used",
                           hdr.class, hdr.tag);
                return NULL;
        }

        zero = bignum_init();
        if (zero == NULL)
                return NULL;

        if (bignum_set_unsigned_bin(zero, hdr.payload, hdr.length) < 0) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Failed to parse INTEGER");
                bignum_deinit(zero);
                return NULL;
        }
        pos = hdr.payload + hdr.length;

        if (bignum_cmp_d(zero, 0) != 0) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected zero INTEGER in the "
                           "beginning of private key; not found; assume "
                           "PKCS #8 not used");
                bignum_deinit(zero);
                return NULL;
        }
        bignum_deinit(zero);

        /* privateKeyAlgorithm PrivateKeyAlgorithmIdentifier
         * (PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier) */
        if (asn1_get_next(pos, len, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected SEQUENCE "
                           "(AlgorithmIdentifier) - found class %d tag 0x%x; "
                           "assume PKCS #8 not used",
                           hdr.class, hdr.tag);
                return NULL;
        }

        if (asn1_get_oid(hdr.payload, hdr.length, &oid, &pos)) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Failed to parse OID "
                           "(algorithm); assume PKCS #8 not used");
                return NULL;
        }

        asn1_oid_to_str(&oid, obuf, sizeof(obuf));
        wpa_printf(MSG_DEBUG, "PKCS #8: algorithm=%s", obuf);

        if (oid.len != 7 ||
            oid.oid[0] != 1 /* iso */ ||
            oid.oid[1] != 2 /* member-body */ ||
            oid.oid[2] != 840 /* us */ ||
            oid.oid[3] != 113549 /* rsadsi */ ||
            oid.oid[4] != 1 /* pkcs */ ||
            oid.oid[5] != 1 /* pkcs-1 */ ||
            oid.oid[6] != 1 /* rsaEncryption */) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Unsupported private key "
                           "algorithm %s", obuf);
                return NULL;
        }

        pos = hdr.payload + hdr.length;

        /* privateKey PrivateKey (PrivateKey ::= OCTET STRING) */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_OCTETSTRING) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected OCTETSTRING "
                           "(privateKey) - found class %d tag 0x%x",
                           hdr.class, hdr.tag);
                return NULL;
        }
        wpa_printf(MSG_DEBUG, "PKCS #8: Try to parse RSAPrivateKey");

        return (struct crypto_private_key *)
                crypto_rsa_import_private_key(hdr.payload, hdr.length);
}


struct crypto_private_key *
pkcs8_enc_key_import(const u8 *buf, size_t len, const char *passwd)
{
        struct asn1_hdr hdr;
        const u8 *pos, *end, *enc_alg;
        size_t enc_alg_len;
        u8 *data;
        size_t data_len;

        if (passwd == NULL)
                return NULL;

        /*
         * PKCS #8, Chapter 7
         * EncryptedPrivateKeyInfo ::= SEQUENCE {
         *   encryptionAlgorithm EncryptionAlgorithmIdentifier,
         *   encryptedData EncryptedData }
         * EncryptionAlgorithmIdentifier ::= AlgorithmIdentifier
         * EncryptedData ::= OCTET STRING
         */

        if (asn1_get_next(buf, len, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Does not start with PKCS #8 "
                           "header (SEQUENCE); assume encrypted PKCS #8 not "
                           "used");
                return NULL;
        }
        pos = hdr.payload;
        end = pos + hdr.length;

        /* encryptionAlgorithm EncryptionAlgorithmIdentifier */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_SEQUENCE) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected SEQUENCE "
                           "(AlgorithmIdentifier) - found class %d tag 0x%x; "
                           "assume encrypted PKCS #8 not used",
                           hdr.class, hdr.tag);
                return NULL;
        }
        enc_alg = hdr.payload;
        enc_alg_len = hdr.length;
        pos = hdr.payload + hdr.length;

        /* encryptedData EncryptedData */
        if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
            hdr.class != ASN1_CLASS_UNIVERSAL ||
            hdr.tag != ASN1_TAG_OCTETSTRING) {
                wpa_printf(MSG_DEBUG, "PKCS #8: Expected OCTETSTRING "
                           "(encryptedData) - found class %d tag 0x%x",
                           hdr.class, hdr.tag);
                return NULL;
        }

        data = pkcs5_decrypt(enc_alg, enc_alg_len, hdr.payload, hdr.length,
                             passwd, &data_len);
        if (data) {
                struct crypto_private_key *key;
                key = pkcs8_key_import(data, data_len);
                os_free(data);
                return key;
        }

        return NULL;
}