Coverage Report

Created: 2020-12-02 17:02

/libfido2/src/rs256.c
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Source (jump to first uncovered line)
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/*
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 * Copyright (c) 2018 Yubico AB. All rights reserved.
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 * Use of this source code is governed by a BSD-style
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 * license that can be found in the LICENSE file.
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 */
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#include <openssl/bn.h>
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#include <openssl/rsa.h>
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#include <openssl/evp.h>
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#include <openssl/obj_mac.h>
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#include <string.h>
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#include "fido.h"
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#include "fido/rs256.h"
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#if OPENSSL_VERSION_NUMBER < 0x10100000L
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static int
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RSA_bits(const RSA *r)
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{
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        return (BN_num_bits(r->n));
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}
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static int
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RSA_set0_key(RSA *r, BIGNUM *n, BIGNUM *e, BIGNUM *d)
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{
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        r->n = n;
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        r->e = e;
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        r->d = d;
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        return (1);
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}
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static void
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RSA_get0_key(const RSA *r, const BIGNUM **n, const BIGNUM **e, const BIGNUM **d)
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{
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        *n = r->n;
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        *e = r->e;
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        *d = r->d;
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}
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#endif /* OPENSSL_VERSION_NUMBER < 0x10100000L */
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static int
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decode_bignum(const cbor_item_t *item, void *ptr, size_t len)
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132
{
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        if (cbor_isa_bytestring(item) == false ||
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            cbor_bytestring_is_definite(item) == false ||
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            cbor_bytestring_length(item) != len) {
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0
                fido_log_debug("%s: cbor type", __func__);
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0
                return (-1);
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0
        }
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132
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        memcpy(ptr, cbor_bytestring_handle(item), len);
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132
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        return (0);
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132
}
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static int
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decode_rsa_pubkey(const cbor_item_t *key, const cbor_item_t *val, void *arg)
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266
{
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        rs256_pk_t *k = arg;
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        if (cbor_isa_negint(key) == false ||
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            cbor_int_get_width(key) != CBOR_INT_8)
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                return (0); /* ignore */
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132
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        switch (cbor_get_uint8(key)) {
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        case 0: /* modulus */
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                return (decode_bignum(val, &k->n, sizeof(k->n)));
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        case 1: /* public exponent */
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                return (decode_bignum(val, &k->e, sizeof(k->e)));
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0
        }
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0
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0
        return (0); /* ignore */
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0
}
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int
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rs256_pk_decode(const cbor_item_t *item, rs256_pk_t *k)
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{
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        if (cbor_isa_map(item) == false ||
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            cbor_map_is_definite(item) == false ||
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            cbor_map_iter(item, k, decode_rsa_pubkey) < 0) {
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5
                fido_log_debug("%s: cbor type", __func__);
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5
                return (-1);
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5
        }
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67
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        return (0);
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}
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rs256_pk_t *
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rs256_pk_new(void)
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863
{
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863
        return (calloc(1, sizeof(rs256_pk_t)));
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863
}
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void
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rs256_pk_free(rs256_pk_t **pkp)
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1.95k
{
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1.95k
        rs256_pk_t *pk;
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1.95k
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1.95k
        if (pkp == NULL || (pk = *pkp) == NULL)
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1.95k
                return;
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860
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        explicit_bzero(pk, sizeof(*pk));
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860
        free(pk);
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860
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        *pkp = NULL;
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860
}
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int
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rs256_pk_from_ptr(rs256_pk_t *pk, const void *ptr, size_t len)
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{
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        if (len < sizeof(*pk))
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                return (FIDO_ERR_INVALID_ARGUMENT);
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        memcpy(pk, ptr, sizeof(*pk));
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        return (FIDO_OK);
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}
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EVP_PKEY *
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rs256_pk_to_EVP_PKEY(const rs256_pk_t *k)
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{
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        RSA             *rsa = NULL;
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        EVP_PKEY        *pkey = NULL;
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        BIGNUM          *n = NULL;
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        BIGNUM          *e = NULL;
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        int              ok = -1;
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        if ((n = BN_new()) == NULL || (e = BN_new()) == NULL)
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                goto fail;
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527
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        if (BN_bin2bn(k->n, sizeof(k->n), n) == NULL ||
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            BN_bin2bn(k->e, sizeof(k->e), e) == NULL) {
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18
                fido_log_debug("%s: BN_bin2bn", __func__);
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                goto fail;
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18
        }
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509
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509
        if ((rsa = RSA_new()) == NULL || RSA_set0_key(rsa, n, e, NULL) == 0) {
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11
                fido_log_debug("%s: RSA_set0_key", __func__);
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                goto fail;
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        }
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498
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        /* at this point, n and e belong to rsa */
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        n = NULL;
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        e = NULL;
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498
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        if ((pkey = EVP_PKEY_new()) == NULL ||
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            EVP_PKEY_assign_RSA(pkey, rsa) == 0) {
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                fido_log_debug("%s: EVP_PKEY_assign_RSA", __func__);
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                goto fail;
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        }
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480
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        rsa = NULL; /* at this point, rsa belongs to evp */
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480
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        ok = 0;
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551
fail:
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        if (n != NULL)
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                BN_free(n);
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551
        if (e != NULL)
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551
                BN_free(e);
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551
        if (rsa != NULL)
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551
                RSA_free(rsa);
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        if (ok < 0 && pkey != NULL) {
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8
                EVP_PKEY_free(pkey);
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8
                pkey = NULL;
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8
        }
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551
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        return (pkey);
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480
}
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int
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rs256_pk_from_RSA(rs256_pk_t *pk, const RSA *rsa)
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{
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        const BIGNUM    *n = NULL;
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        const BIGNUM    *e = NULL;
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        const BIGNUM    *d = NULL;
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        int              k;
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409
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409
        if (RSA_bits(rsa) != 2048) {
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388
                fido_log_debug("%s: invalid key length", __func__);
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                return (FIDO_ERR_INVALID_ARGUMENT);
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        }
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21
184
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        RSA_get0_key(rsa, &n, &e, &d);
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21
186
21
        if (n == NULL || e == NULL) {
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0
                fido_log_debug("%s: RSA_get0_key", __func__);
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0
                return (FIDO_ERR_INTERNAL);
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0
        }
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21
191
21
        if ((k = BN_num_bytes(n)) < 0 || (size_t)k > sizeof(pk->n) ||
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21
            (k = BN_num_bytes(e)) < 0 || (size_t)k > sizeof(pk->e)) {
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0
                fido_log_debug("%s: invalid key", __func__);
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0
                return (FIDO_ERR_INTERNAL);
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0
        }
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21
197
21
        if ((k = BN_bn2bin(n, pk->n)) < 0 || (size_t)k > sizeof(pk->n) ||
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21
            (k = BN_bn2bin(e, pk->e)) < 0 || (size_t)k > sizeof(pk->e)) {
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3
                fido_log_debug("%s: BN_bn2bin", __func__);
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3
                return (FIDO_ERR_INTERNAL);
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3
        }
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18
203
18
        return (FIDO_OK);
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18
}