Coverage Report

Created: 2025-06-13 06:57

/src/openssl/crypto/ffc/ffc_key_validate.c
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Count
Source (jump to first uncovered line)
1
/*
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 * Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved.
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 *
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 * Licensed under the Apache License 2.0 (the "License").  You may not use
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 * this file except in compliance with the License.  You can obtain a copy
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 * in the file LICENSE in the source distribution or at
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 * https://www.openssl.org/source/license.html
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 */
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#include "internal/ffc.h"
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12
/*
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 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
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 * To only be used with ephemeral FFC public keys generated using the approved
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 * safe-prime groups. (Checks that the public key is in the range [2, p - 1]
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 *
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 * ret contains 0 on success, or error flags (see FFC_ERROR_PUBKEY_TOO_SMALL)
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 */
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int ossl_ffc_validate_public_key_partial(const FFC_PARAMS *params,
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                                         const BIGNUM *pub_key, int *ret)
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0
{
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0
    int ok = 0;
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0
    BIGNUM *tmp = NULL;
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0
    BN_CTX *ctx = NULL;
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0
    *ret = 0;
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0
    if (params == NULL || pub_key == NULL || params->p == NULL) {
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0
        *ret = FFC_ERROR_PASSED_NULL_PARAM;
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0
        return 1;
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0
    }
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0
    ctx = BN_CTX_new_ex(NULL);
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0
    if (ctx == NULL)
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0
        goto err;
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0
    BN_CTX_start(ctx);
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0
    tmp = BN_CTX_get(ctx);
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    /* Step(1): Verify pub_key >= 2 */
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0
    if (tmp == NULL
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0
        || !BN_set_word(tmp, 1))
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0
        goto err;
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0
    if (BN_cmp(pub_key, tmp) <= 0)
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0
        *ret |= FFC_ERROR_PUBKEY_TOO_SMALL;
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    /* Step(1): Verify pub_key <=  p-2 */
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0
    if (BN_copy(tmp, params->p) == NULL
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0
        || !BN_sub_word(tmp, 1))
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0
        goto err;
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0
    if (BN_cmp(pub_key, tmp) >= 0)
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0
        *ret |= FFC_ERROR_PUBKEY_TOO_LARGE;
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0
    ok = 1;
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0
 err:
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0
    if (ctx != NULL) {
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0
        BN_CTX_end(ctx);
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0
        BN_CTX_free(ctx);
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0
    }
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0
    return ok;
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0
}
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/*
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 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
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 */
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int ossl_ffc_validate_public_key(const FFC_PARAMS *params,
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                                 const BIGNUM *pub_key, int *ret)
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0
{
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0
    int ok = 0;
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0
    BIGNUM *tmp = NULL;
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0
    BN_CTX *ctx = NULL;
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0
    if (!ossl_ffc_validate_public_key_partial(params, pub_key, ret))
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0
        return 0;
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0
    if (*ret == 0 && params->q != NULL) {
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0
        ctx = BN_CTX_new_ex(NULL);
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0
        if (ctx == NULL)
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0
            goto err;
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0
        BN_CTX_start(ctx);
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0
        tmp = BN_CTX_get(ctx);
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        /* Check pub_key^q == 1 mod p */
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0
        if (tmp == NULL
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0
            || !BN_mod_exp(tmp, pub_key, params->q, params->p, ctx))
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0
            goto err;
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0
        if (!BN_is_one(tmp))
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0
            *ret |= FFC_ERROR_PUBKEY_INVALID;
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0
    }
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0
    ok = 1;
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0
 err:
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0
    if (ctx != NULL) {
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0
        BN_CTX_end(ctx);
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0
        BN_CTX_free(ctx);
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0
    }
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0
    return ok;
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0
}
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/*
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 * See SP800-56Ar3 Section 5.6.2.1.2: Owner assurance of Private key validity.
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 * Verifies priv_key is in the range [1..upper-1]. The passed in value of upper
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 * is normally params->q but can be 2^N for approved safe prime groups.
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 * Note: This assumes that the domain parameters are valid.
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 */
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int ossl_ffc_validate_private_key(const BIGNUM *upper, const BIGNUM *priv,
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                                  int *ret)
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0
{
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0
    int ok = 0;
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0
    *ret = 0;
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109
0
    if (priv == NULL || upper == NULL) {
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0
        *ret = FFC_ERROR_PASSED_NULL_PARAM;
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0
        goto err;
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0
    }
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0
    if (BN_cmp(priv, BN_value_one()) < 0) {
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0
        *ret |= FFC_ERROR_PRIVKEY_TOO_SMALL;
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0
        goto err;
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0
    }
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0
    if (BN_cmp(priv, upper) >= 0) {
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0
        *ret |= FFC_ERROR_PRIVKEY_TOO_LARGE;
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0
        goto err;
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0
    }
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0
    ok = 1;
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0
err:
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0
    return ok;
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0
}