Coverage Report

Created: 2022-01-17 10:46

/libfido2/src/eddsa.c
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Source (jump to first uncovered line)
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/*
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 * Copyright (c) 2019-2021 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/obj_mac.h>
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#include "fido.h"
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#include "fido/eddsa.h"
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#if defined(LIBRESSL_VERSION_NUMBER)
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EVP_PKEY *
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EVP_PKEY_new_raw_public_key(int type, ENGINE *e, const unsigned char *key,
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    size_t keylen)
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{
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        (void)type;
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        (void)e;
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        (void)key;
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        (void)keylen;
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        fido_log_debug("%s: unimplemented", __func__);
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        return (NULL);
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}
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int
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EVP_PKEY_get_raw_public_key(const EVP_PKEY *pkey, unsigned char *pub,
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    size_t *len)
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{
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        (void)pkey;
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        (void)pub;
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        (void)len;
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        fido_log_debug("%s: unimplemented", __func__);
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        return (0);
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}
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#endif /* LIBRESSL_VERSION_NUMBER */
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#if defined(LIBRESSL_VERSION_NUMBER) && LIBRESSL_VERSION_NUMBER < 0x3040000f
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int
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EVP_DigestVerify(EVP_MD_CTX *ctx, const unsigned char *sigret, size_t siglen,
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    const unsigned char *tbs, size_t tbslen)
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{
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        (void)ctx;
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        (void)sigret;
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        (void)siglen;
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        (void)tbs;
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        (void)tbslen;
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        fido_log_debug("%s: unimplemented", __func__);
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        return (0);
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}
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#endif /* LIBRESSL_VERSION_NUMBER < 0x3040000f */
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static int
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decode_coord(const cbor_item_t *item, void *xy, size_t xy_len)
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218
{
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218
        if (cbor_isa_bytestring(item) == false ||
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218
            cbor_bytestring_is_definite(item) == false ||
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218
            cbor_bytestring_length(item) != xy_len) {
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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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213
        memcpy(xy, cbor_bytestring_handle(item), xy_len);
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213
        return (0);
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}
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static int
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decode_pubkey_point(const cbor_item_t *key, const cbor_item_t *val, void *arg)
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945
{
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945
        eddsa_pk_t *k = arg;
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945
        if (cbor_isa_negint(key) == false ||
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945
            cbor_int_get_width(key) != CBOR_INT_8)
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486
                return (0); /* ignore */
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459
        switch (cbor_get_uint8(key)) {
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218
        case 1: /* x coordinate */
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218
                return (decode_coord(val, &k->x, sizeof(k->x)));
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241
        }
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        return (0); /* ignore */
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}
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int
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eddsa_pk_decode(const cbor_item_t *item, eddsa_pk_t *k)
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241
{
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241
        if (cbor_isa_map(item) == false ||
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241
            cbor_map_is_definite(item) == false ||
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241
            cbor_map_iter(item, k, decode_pubkey_point) < 0) {
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9
                fido_log_debug("%s: cbor type", __func__);
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9
                return (-1);
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9
        }
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101
232
        return (0);
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232
}
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eddsa_pk_t *
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eddsa_pk_new(void)
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2.76k
{
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2.76k
        return (calloc(1, sizeof(eddsa_pk_t)));
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2.76k
}
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void
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eddsa_pk_free(eddsa_pk_t **pkp)
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3.72k
{
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3.72k
        eddsa_pk_t *pk;
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3.72k
        if (pkp == NULL || (pk = *pkp) == NULL)
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3.72k
                return;
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2.75k
        freezero(pk, sizeof(*pk));
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2.75k
        *pkp = NULL;
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2.75k
}
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int
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eddsa_pk_from_ptr(eddsa_pk_t *pk, const void *ptr, size_t len)
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1.38k
{
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1.38k
        if (len < sizeof(*pk))
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1.36k
                return (FIDO_ERR_INVALID_ARGUMENT);
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16
        memcpy(pk, ptr, sizeof(*pk));
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16
        return (FIDO_OK);
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16
}
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EVP_PKEY *
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eddsa_pk_to_EVP_PKEY(const eddsa_pk_t *k)
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1.48k
{
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1.48k
        EVP_PKEY *pkey = NULL;
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1.48k
        if ((pkey = EVP_PKEY_new_raw_public_key(EVP_PKEY_ED25519, NULL, k->x,
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1.48k
            sizeof(k->x))) == NULL)
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1.48k
                fido_log_debug("%s: EVP_PKEY_new_raw_public_key", __func__);
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1.48k
        return (pkey);
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1.48k
}
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int
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eddsa_pk_from_EVP_PKEY(eddsa_pk_t *pk, const EVP_PKEY *pkey)
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1.36k
{
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1.36k
        size_t len = 0;
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1.36k
        if (EVP_PKEY_get_raw_public_key(pkey, NULL, &len) != 1 ||
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1.36k
            len != sizeof(pk->x))
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6
                return (FIDO_ERR_INTERNAL);
153
1.36k
        if (EVP_PKEY_get_raw_public_key(pkey, pk->x, &len) != 1 ||
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1.36k
            len != sizeof(pk->x))
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6
                return (FIDO_ERR_INTERNAL);
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157
1.35k
        return (FIDO_OK);
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1.35k
}
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int
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eddsa_verify_sig(const fido_blob_t *dgst, EVP_PKEY *pkey,
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    const fido_blob_t *sig)
163
94
{
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94
        EVP_MD_CTX      *mdctx = NULL;
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94
        int              ok = -1;
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167
94
        if (EVP_PKEY_base_id(pkey) != EVP_PKEY_ED25519) {
168
1
                fido_log_debug("%s: EVP_PKEY_base_id", __func__);
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1
                goto fail;
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1
        }
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        /* EVP_DigestVerify needs ints */
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93
        if (dgst->len > INT_MAX || sig->len > INT_MAX) {
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0
                fido_log_debug("%s: dgst->len=%zu, sig->len=%zu", __func__,
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0
                    dgst->len, sig->len);
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0
                return (-1);
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0
        }
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179
93
        if ((mdctx = EVP_MD_CTX_new()) == NULL) {
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4
                fido_log_debug("%s: EVP_MD_CTX_new", __func__);
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4
                goto fail;
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4
        }
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184
89
        if (EVP_DigestVerifyInit(mdctx, NULL, NULL, NULL, pkey) != 1) {
185
4
                fido_log_debug("%s: EVP_DigestVerifyInit", __func__);
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4
                goto fail;
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4
        }
188
189
85
        if (EVP_DigestVerify(mdctx, sig->ptr, sig->len, dgst->ptr,
190
85
            dgst->len) != 1) {
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85
                fido_log_debug("%s: EVP_DigestVerify", __func__);
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85
                goto fail;
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85
        }
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195
0
        ok = 0;
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94
fail:
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94
        EVP_MD_CTX_free(mdctx);
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199
94
        return (ok);
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0
}
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202
int
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eddsa_pk_verify_sig(const fido_blob_t *dgst, const eddsa_pk_t *pk,
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    const fido_blob_t *sig)
205
97
{
206
97
        EVP_PKEY        *pkey;
207
97
        int              ok = -1;
208
209
97
        if ((pkey = eddsa_pk_to_EVP_PKEY(pk)) == NULL ||
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97
            eddsa_verify_sig(dgst, pkey, sig) < 0) {
211
97
                fido_log_debug("%s: eddsa_verify_sig", __func__);
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97
                goto fail;
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97
        }
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215
0
        ok = 0;
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97
fail:
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97
        EVP_PKEY_free(pkey);
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219
97
        return (ok);
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0
}