/*

 * Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#ifdef OPENSSL_NO_CT

# error "CT disabled"

#endif

#include <openssl/ct.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/tls1.h>

#include <openssl/x509.h>

#include "ct_local.h"

SCT *SCT_new(void)

{

    SCT *sct = OPENSSL_zalloc(sizeof(*sct));

    if (sct == NULL)

        return NULL;

    sct->entry_type = CT_LOG_ENTRY_TYPE_NOT_SET;

    sct->version = SCT_VERSION_NOT_SET;

    return sct;

}

void SCT_free(SCT *sct)

{

    if (sct == NULL)

        return;

    OPENSSL_free(sct->log_id);

    OPENSSL_free(sct->ext);

    OPENSSL_free(sct->sig);

    OPENSSL_free(sct->sct);

    OPENSSL_free(sct);

}

void SCT_LIST_free(STACK_OF(SCT) *a)

{

    sk_SCT_pop_free(a, SCT_free);

}

int SCT_set_version(SCT *sct, sct_version_t version)

{

    if (version != SCT_VERSION_V1) {

        ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_VERSION);

        return 0;

    }

    sct->version = version;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    return 1;

}

int SCT_set_log_entry_type(SCT *sct, ct_log_entry_type_t entry_type)

{

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    switch (entry_type) {

    case CT_LOG_ENTRY_TYPE_X509:

    case CT_LOG_ENTRY_TYPE_PRECERT:

        sct->entry_type = entry_type;

        return 1;

    case CT_LOG_ENTRY_TYPE_NOT_SET:

        break;

    }

    ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_ENTRY_TYPE);

    return 0;

}

int SCT_set0_log_id(SCT *sct, unsigned char *log_id, size_t log_id_len)

{

    if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {

        ERR_raise(ERR_LIB_CT, CT_R_INVALID_LOG_ID_LENGTH);

        return 0;

    }

    OPENSSL_free(sct->log_id);

    sct->log_id = log_id;

    sct->log_id_len = log_id_len;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    return 1;

}

int SCT_set1_log_id(SCT *sct, const unsigned char *log_id, size_t log_id_len)

{

    if (sct->version == SCT_VERSION_V1 && log_id_len != CT_V1_HASHLEN) {

        ERR_raise(ERR_LIB_CT, CT_R_INVALID_LOG_ID_LENGTH);

        return 0;

    }

    OPENSSL_free(sct->log_id);

    sct->log_id = NULL;

    sct->log_id_len = 0;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    if (log_id != NULL && log_id_len > 0) {

        sct->log_id = OPENSSL_memdup(log_id, log_id_len);

        if (sct->log_id == NULL)

            return 0;

        sct->log_id_len = log_id_len;

    }

    return 1;

}

void SCT_set_timestamp(SCT *sct, uint64_t timestamp)

{

    sct->timestamp = timestamp;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

}

int SCT_set_signature_nid(SCT *sct, int nid)

{

    switch (nid) {

    case NID_sha256WithRSAEncryption:

        sct->hash_alg = TLSEXT_hash_sha256;

        sct->sig_alg = TLSEXT_signature_rsa;

        sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

        return 1;

    case NID_ecdsa_with_SHA256:

        sct->hash_alg = TLSEXT_hash_sha256;

        sct->sig_alg = TLSEXT_signature_ecdsa;

        sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

        return 1;

    default:

        ERR_raise(ERR_LIB_CT, CT_R_UNRECOGNIZED_SIGNATURE_NID);

        return 0;

    }

}

void SCT_set0_extensions(SCT *sct, unsigned char *ext, size_t ext_len)

{

    OPENSSL_free(sct->ext);

    sct->ext = ext;

    sct->ext_len = ext_len;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

}

int SCT_set1_extensions(SCT *sct, const unsigned char *ext, size_t ext_len)

{

    OPENSSL_free(sct->ext);

    sct->ext = NULL;

    sct->ext_len = 0;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    if (ext != NULL && ext_len > 0) {

        sct->ext = OPENSSL_memdup(ext, ext_len);

        if (sct->ext == NULL)

            return 0;

        sct->ext_len = ext_len;

    }

    return 1;

}

void SCT_set0_signature(SCT *sct, unsigned char *sig, size_t sig_len)

{

    OPENSSL_free(sct->sig);

    sct->sig = sig;

    sct->sig_len = sig_len;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

}

int SCT_set1_signature(SCT *sct, const unsigned char *sig, size_t sig_len)

{

    OPENSSL_free(sct->sig);

    sct->sig = NULL;

    sct->sig_len = 0;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    if (sig != NULL && sig_len > 0) {

        sct->sig = OPENSSL_memdup(sig, sig_len);

        if (sct->sig == NULL)

            return 0;

        sct->sig_len = sig_len;

    }

    return 1;

}

sct_version_t SCT_get_version(const SCT *sct)

{

    return sct->version;

}

ct_log_entry_type_t SCT_get_log_entry_type(const SCT *sct)

{

    return sct->entry_type;

}

size_t SCT_get0_log_id(const SCT *sct, unsigned char **log_id)

{

    *log_id = sct->log_id;

    return sct->log_id_len;

}

uint64_t SCT_get_timestamp(const SCT *sct)

{

    return sct->timestamp;

}

int SCT_get_signature_nid(const SCT *sct)

{

    if (sct->version == SCT_VERSION_V1) {

        if (sct->hash_alg == TLSEXT_hash_sha256) {

            switch (sct->sig_alg) {

            case TLSEXT_signature_ecdsa:

                return NID_ecdsa_with_SHA256;

            case TLSEXT_signature_rsa:

                return NID_sha256WithRSAEncryption;

            default:

                return NID_undef;

            }

        }

    }

    return NID_undef;

}

size_t SCT_get0_extensions(const SCT *sct, unsigned char **ext)

{

    *ext = sct->ext;

    return sct->ext_len;

}

size_t SCT_get0_signature(const SCT *sct, unsigned char **sig)

{

    *sig = sct->sig;

    return sct->sig_len;

}

int SCT_is_complete(const SCT *sct)

{

    switch (sct->version) {

    case SCT_VERSION_NOT_SET:

        return 0;

    case SCT_VERSION_V1:

        return sct->log_id != NULL && SCT_signature_is_complete(sct);

    default:

        return sct->sct != NULL; /* Just need cached encoding */

    }

}

int SCT_signature_is_complete(const SCT *sct)

{

    return SCT_get_signature_nid(sct) != NID_undef &&

        sct->sig != NULL && sct->sig_len > 0;

}

sct_source_t SCT_get_source(const SCT *sct)

{

    return sct->source;

}

int SCT_set_source(SCT *sct, sct_source_t source)

{

    sct->source = source;

    sct->validation_status = SCT_VALIDATION_STATUS_NOT_SET;

    switch (source) {

    case SCT_SOURCE_TLS_EXTENSION:

    case SCT_SOURCE_OCSP_STAPLED_RESPONSE:

        return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_X509);

    case SCT_SOURCE_X509V3_EXTENSION:

        return SCT_set_log_entry_type(sct, CT_LOG_ENTRY_TYPE_PRECERT);

    case SCT_SOURCE_UNKNOWN:

        break;

    }

    /* if we aren't sure, leave the log entry type alone */

    return 1;

}

sct_validation_status_t SCT_get_validation_status(const SCT *sct)

{

    return sct->validation_status;

}

int SCT_validate(SCT *sct, const CT_POLICY_EVAL_CTX *ctx)

{

    int is_sct_valid = -1;

    SCT_CTX *sctx = NULL;

    X509_PUBKEY *pub = NULL, *log_pkey = NULL;

    const CTLOG *log;

    /*

     * With an unrecognized SCT version we don't know what such an SCT means,

     * let alone validate one.  So we return validation failure (0).

     */

    if (sct->version != SCT_VERSION_V1) {

        sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_VERSION;

        return 0;

    }

    log = CTLOG_STORE_get0_log_by_id(ctx->log_store,

                                     sct->log_id, sct->log_id_len);

    /* Similarly, an SCT from an unknown log also cannot be validated. */

    if (log == NULL) {

        sct->validation_status = SCT_VALIDATION_STATUS_UNKNOWN_LOG;

        return 0;

    }

    sctx = SCT_CTX_new(ctx->libctx, ctx->propq);

    if (sctx == NULL)

        goto err;

    if (X509_PUBKEY_set(&log_pkey, CTLOG_get0_public_key(log)) != 1)

        goto err;

    if (SCT_CTX_set1_pubkey(sctx, log_pkey) != 1)

        goto err;

    if (SCT_get_log_entry_type(sct) == CT_LOG_ENTRY_TYPE_PRECERT) {

        EVP_PKEY *issuer_pkey;

        if (ctx->issuer == NULL) {

            sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;

            goto end;

        }

        issuer_pkey = X509_get0_pubkey(ctx->issuer);

        if (X509_PUBKEY_set(&pub, issuer_pkey) != 1)

            goto err;

        if (SCT_CTX_set1_issuer_pubkey(sctx, pub) != 1)

            goto err;

    }

    SCT_CTX_set_time(sctx, ctx->epoch_time_in_ms);

    /*

     * XXX: Potential for optimization.  This repeats some idempotent heavy

     * lifting on the certificate for each candidate SCT, and appears to not

     * use any information in the SCT itself, only the certificate is

     * processed.  So it may make more sense to do this just once, perhaps

     * associated with the shared (by all SCTs) policy eval ctx.

     *

     * XXX: Failure here is global (SCT independent) and represents either an

     * issue with the certificate (e.g. duplicate extensions) or an out of

     * memory condition.  When the certificate is incompatible with CT, we just

     * mark the SCTs invalid, rather than report a failure to determine the

     * validation status.  That way, callbacks that want to do "soft" SCT

     * processing will not abort handshakes with false positive internal

     * errors.  Since the function does not distinguish between certificate

     * issues (peer's fault) and internal problems (out fault) the safe thing

     * to do is to report a validation failure and let the callback or

     * application decide what to do.

     */

    if (SCT_CTX_set1_cert(sctx, ctx->cert, NULL) != 1)

        sct->validation_status = SCT_VALIDATION_STATUS_UNVERIFIED;

    else

        sct->validation_status = SCT_CTX_verify(sctx, sct) == 1 ?

            SCT_VALIDATION_STATUS_VALID : SCT_VALIDATION_STATUS_INVALID;

end:

    is_sct_valid = sct->validation_status == SCT_VALIDATION_STATUS_VALID;

err:

    X509_PUBKEY_free(pub);

    X509_PUBKEY_free(log_pkey);

    SCT_CTX_free(sctx);

    return is_sct_valid;

}

int SCT_LIST_validate(const STACK_OF(SCT) *scts, CT_POLICY_EVAL_CTX *ctx)

{

    int are_scts_valid = 1;

    int sct_count = scts != NULL ? sk_SCT_num(scts) : 0;

    int i;

    for (i = 0; i < sct_count; ++i) {

        int is_sct_valid = -1;

        SCT *sct = sk_SCT_value(scts, i);

        if (sct == NULL)

            continue;

        is_sct_valid = SCT_validate(sct, ctx);

        if (is_sct_valid < 0)

            return is_sct_valid;

        are_scts_valid &= is_sct_valid;

    }

    return are_scts_valid;

}