/*

 * Copyright 2016-2020 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 is disabled"

#endif

#include <limits.h>

#include <string.h>

#include <openssl/asn1.h>

#include <openssl/buffer.h>

#include <openssl/ct.h>

#include <openssl/err.h>

#include "ct_local.h"

int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len)

{

    size_t siglen;

    size_t len_remaining = len;

    const unsigned char *p;

    if (sct->version != SCT_VERSION_V1) {

        ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_VERSION);

        return -1;

    }

    /*

     * digitally-signed struct header: (1 byte) Hash algorithm (1 byte)

     * Signature algorithm (2 bytes + ?) Signature

     *

     * This explicitly rejects empty signatures: they're invalid for

     * all supported algorithms.

     */

    if (len <= 4) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID_SIGNATURE);

        return -1;

    }

    p = *in;

    /* Get hash and signature algorithm */

    sct->hash_alg = *p++;

    sct->sig_alg = *p++;

    if (SCT_get_signature_nid(sct) == NID_undef) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID_SIGNATURE);

        return -1;

    }

    /* Retrieve signature and check it is consistent with the buffer length */

    n2s(p, siglen);

    len_remaining -= (p - *in);

    if (siglen > len_remaining) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID_SIGNATURE);

        return -1;

    }

    if (SCT_set1_signature(sct, p, siglen) != 1)

        return -1;

    len_remaining -= siglen;

    *in = p + siglen;

    return len - len_remaining;

}

SCT *o2i_SCT(SCT **psct, const unsigned char **in, size_t len)

{

    SCT *sct = NULL;

    const unsigned char *p;

    if (len == 0 || len > MAX_SCT_SIZE) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID);

        goto err;

    }

    if ((sct = SCT_new()) == NULL)

        goto err;

    p = *in;

    sct->version = *p;

    if (sct->version == SCT_VERSION_V1) {

        int sig_len;

        size_t len2;

        /*-

         * Fixed-length header:

         *   struct {

         *     Version sct_version;     (1 byte)

         *     log_id id;               (32 bytes)

         *     uint64 timestamp;        (8 bytes)

         *     CtExtensions extensions; (2 bytes + ?)

         *   }

         */

        if (len < 43) {

            ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID);

            goto err;

        }

        len -= 43;

        p++;

        sct->log_id = OPENSSL_memdup(p, CT_V1_HASHLEN);

        if (sct->log_id == NULL)

            goto err;

        sct->log_id_len = CT_V1_HASHLEN;

        p += CT_V1_HASHLEN;

        n2l8(p, sct->timestamp);

        n2s(p, len2);

        if (len < len2) {

            ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID);

            goto err;

        }

        if (len2 > 0) {

            sct->ext = OPENSSL_memdup(p, len2);

            if (sct->ext == NULL)

                goto err;

        }

        sct->ext_len = len2;

        p += len2;

        len -= len2;

        sig_len = o2i_SCT_signature(sct, &p, len);

        if (sig_len <= 0) {

            ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID);

            goto err;

        }

        len -= sig_len;

        *in = p + len;

    } else {

        /* If not V1 just cache encoding */

        sct->sct = OPENSSL_memdup(p, len);

        if (sct->sct == NULL)

            goto err;

        sct->sct_len = len;

        *in = p + len;

    }

    if (psct != NULL) {

        SCT_free(*psct);

        *psct = sct;

    }

    return sct;

err:

    SCT_free(sct);

    return NULL;

}

int i2o_SCT_signature(const SCT *sct, unsigned char **out)

{

    size_t len;

    unsigned char *p = NULL, *pstart = NULL;

    if (!SCT_signature_is_complete(sct)) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_INVALID_SIGNATURE);

        goto err;

    }

    if (sct->version != SCT_VERSION_V1) {

        ERR_raise(ERR_LIB_CT, CT_R_UNSUPPORTED_VERSION);

        goto err;

    }

    /*

    * (1 byte) Hash algorithm

    * (1 byte) Signature algorithm

    * (2 bytes + ?) Signature

    */

    len = 4 + sct->sig_len;

    if (out != NULL) {

        if (*out != NULL) {

            p = *out;

            *out += len;

        } else {

            pstart = p = OPENSSL_malloc(len);

            if (p == NULL) {

                ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);

                goto err;

            }

            *out = p;

        }

        *p++ = sct->hash_alg;

        *p++ = sct->sig_alg;

        s2n(sct->sig_len, p);

        memcpy(p, sct->sig, sct->sig_len);

    }

    return len;

err:

    OPENSSL_free(pstart);

    return -1;

}

int i2o_SCT(const SCT *sct, unsigned char **out)

{

    size_t len;

    unsigned char *p = NULL, *pstart = NULL;

    if (!SCT_is_complete(sct)) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_NOT_SET);

        goto err;

    }

    /*

     * Fixed-length header: struct { (1 byte) Version sct_version; (32 bytes)

     * log_id id; (8 bytes) uint64 timestamp; (2 bytes + ?) CtExtensions

     * extensions; (1 byte) Hash algorithm (1 byte) Signature algorithm (2

     * bytes + ?) Signature

     */

    if (sct->version == SCT_VERSION_V1)

        len = 43 + sct->ext_len + 4 + sct->sig_len;

    else

        len = sct->sct_len;

    if (out == NULL)

        return len;

    if (*out != NULL) {

        p = *out;

        *out += len;

    } else {

        pstart = p = OPENSSL_malloc(len);

        if (p == NULL) {

            ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        *out = p;

    }

    if (sct->version == SCT_VERSION_V1) {

        *p++ = sct->version;

        memcpy(p, sct->log_id, CT_V1_HASHLEN);

        p += CT_V1_HASHLEN;

        l2n8(sct->timestamp, p);

        s2n(sct->ext_len, p);

        if (sct->ext_len > 0) {

            memcpy(p, sct->ext, sct->ext_len);

            p += sct->ext_len;

        }

        if (i2o_SCT_signature(sct, &p) <= 0)

            goto err;

    } else {

        memcpy(p, sct->sct, len);

    }

    return len;

err:

    OPENSSL_free(pstart);

    return -1;

}

STACK_OF(SCT) *o2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,

                            size_t len)

{

    STACK_OF(SCT) *sk = NULL;

    size_t list_len, sct_len;

    if (len < 2 || len > MAX_SCT_LIST_SIZE) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_LIST_INVALID);

        return NULL;

    }

    n2s(*pp, list_len);

    if (list_len != len - 2) {

        ERR_raise(ERR_LIB_CT, CT_R_SCT_LIST_INVALID);

        return NULL;

    }

    if (a == NULL || *a == NULL) {

        sk = sk_SCT_new_null();

        if (sk == NULL)

            return NULL;

    } else {

        SCT *sct;

        /* Use the given stack, but empty it first. */

        sk = *a;

        while ((sct = sk_SCT_pop(sk)) != NULL)

            SCT_free(sct);

    }

    while (list_len > 0) {

        SCT *sct;

        if (list_len < 2) {

            ERR_raise(ERR_LIB_CT, CT_R_SCT_LIST_INVALID);

            goto err;

        }

        n2s(*pp, sct_len);

        list_len -= 2;

        if (sct_len == 0 || sct_len > list_len) {

            ERR_raise(ERR_LIB_CT, CT_R_SCT_LIST_INVALID);

            goto err;

        }

        list_len -= sct_len;

        if ((sct = o2i_SCT(NULL, pp, sct_len)) == NULL)

            goto err;

        if (!sk_SCT_push(sk, sct)) {

            SCT_free(sct);

            goto err;

        }

    }

    if (a != NULL && *a == NULL)

        *a = sk;

    return sk;

 err:

    if (a == NULL || *a == NULL)

        SCT_LIST_free(sk);

    return NULL;

}

int i2o_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **pp)

{

    int len, sct_len, i, is_pp_new = 0;

    size_t len2;

    unsigned char *p = NULL, *p2;

    if (pp != NULL) {

        if (*pp == NULL) {

            if ((len = i2o_SCT_LIST(a, NULL)) == -1) {

                ERR_raise(ERR_LIB_CT, CT_R_SCT_LIST_INVALID);

                return -1;

            }

            if ((*pp = OPENSSL_malloc(len)) == NULL) {

                ERR_raise(ERR_LIB_CT, ERR_R_MALLOC_FAILURE);

                return -1;

            }

            is_pp_new = 1;

        }

        p = *pp + 2;

    }

    len2 = 2;

    for (i = 0; i < sk_SCT_num(a); i++) {

        if (pp != NULL) {

            p2 = p;

            p += 2;

            if ((sct_len = i2o_SCT(sk_SCT_value(a, i), &p)) == -1)

                goto err;

            s2n(sct_len, p2);

        } else {

          if ((sct_len = i2o_SCT(sk_SCT_value(a, i), NULL)) == -1)

              goto err;

        }

        len2 += 2 + sct_len;

    }

    if (len2 > MAX_SCT_LIST_SIZE)

        goto err;

    if (pp != NULL) {

        p = *pp;

        s2n(len2 - 2, p);

        if (!is_pp_new)

            *pp += len2;

    }

    return len2;

 err:

    if (is_pp_new) {

        OPENSSL_free(*pp);

        *pp = NULL;

    }

    return -1;

}

STACK_OF(SCT) *d2i_SCT_LIST(STACK_OF(SCT) **a, const unsigned char **pp,

                            long len)

{

    ASN1_OCTET_STRING *oct = NULL;

    STACK_OF(SCT) *sk = NULL;

    const unsigned char *p;

    p = *pp;

    if (d2i_ASN1_OCTET_STRING(&oct, &p, len) == NULL)

        return NULL;

    p = oct->data;

    if ((sk = o2i_SCT_LIST(a, &p, oct->length)) != NULL)

        *pp += len;

    ASN1_OCTET_STRING_free(oct);

    return sk;

}

int i2d_SCT_LIST(const STACK_OF(SCT) *a, unsigned char **out)

{

    ASN1_OCTET_STRING oct;

    int len;

    oct.data = NULL;

    if ((oct.length = i2o_SCT_LIST(a, &oct.data)) == -1)

        return -1;

    len = i2d_ASN1_OCTET_STRING(&oct, out);

    OPENSSL_free(oct.data);

    return len;

}