/*

 * Copyright 2000-2021 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

 */

#include <stddef.h>

#include <string.h>

#include "internal/cryptlib.h"

#include "internal/refcount.h"

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/objects.h>

#include <openssl/err.h>

#include "asn1_local.h"

/* Utility functions for manipulating fields and offsets */

/* Add 'offset' to 'addr' */

#define offset2ptr(addr, offset) (void *)(((char *) addr) + offset)

/*

 * Given an ASN1_ITEM CHOICE type return the selector value

 */

int ossl_asn1_get_choice_selector(ASN1_VALUE **pval, const ASN1_ITEM *it)

{

    int *sel = offset2ptr(*pval, it->utype);

    return *sel;

}

int ossl_asn1_get_choice_selector_const(const ASN1_VALUE **pval,

                                        const ASN1_ITEM *it)

{

    int *sel = offset2ptr(*pval, it->utype);

    return *sel;

}

/*

 * Given an ASN1_ITEM CHOICE type set the selector value, return old value.

 */

int ossl_asn1_set_choice_selector(ASN1_VALUE **pval, int value,

                                  const ASN1_ITEM *it)

{

    int *sel, ret;

    sel = offset2ptr(*pval, it->utype);

    ret = *sel;

    *sel = value;

    return ret;

}

/*

 * Do atomic reference counting. The value 'op' decides what to do.

 * If it is +1 then the count is incremented.

 * If |op| is 0, lock is initialised and count is set to 1.

 * If |op| is -1, count is decremented and the return value is the current

 * reference count or 0 if no reference count is active.

 * It returns -1 on initialisation error.

 * Used by ASN1_SEQUENCE construct of X509, X509_REQ, X509_CRL objects

 */

int ossl_asn1_do_lock(ASN1_VALUE **pval, int op, const ASN1_ITEM *it)

{

    const ASN1_AUX *aux;

    CRYPTO_REF_COUNT *lck;

    CRYPTO_RWLOCK **lock;

    int ret = -1;

    if ((it->itype != ASN1_ITYPE_SEQUENCE)

        && (it->itype != ASN1_ITYPE_NDEF_SEQUENCE))

        return 0;

    aux = it->funcs;

    if (aux == NULL || (aux->flags & ASN1_AFLG_REFCOUNT) == 0)

        return 0;

    lck = offset2ptr(*pval, aux->ref_offset);

    lock = offset2ptr(*pval, aux->ref_lock);

    switch (op) {

    case 0:

        *lck = ret = 1;

        *lock = CRYPTO_THREAD_lock_new();

        if (*lock == NULL) {

            ERR_raise(ERR_LIB_ASN1, ERR_R_CRYPTO_LIB);

            return -1;

        }

        break;

    case 1:

        if (!CRYPTO_UP_REF(lck, &ret, *lock))

            return -1;

        break;

    case -1:

        if (!CRYPTO_DOWN_REF(lck, &ret, *lock))

            return -1;  /* failed */

        REF_PRINT_EX(it->sname, ret, (void *)it);

        REF_ASSERT_ISNT(ret < 0);

        if (ret == 0) {

            CRYPTO_THREAD_lock_free(*lock);

            *lock = NULL;

        }

        break;

    }

    return ret;

}

static ASN1_ENCODING *asn1_get_enc_ptr(ASN1_VALUE **pval, const ASN1_ITEM *it)

{

    const ASN1_AUX *aux;

    if (pval == NULL || *pval == NULL)

        return NULL;

    aux = it->funcs;

    if (aux == NULL || (aux->flags & ASN1_AFLG_ENCODING) == 0)

        return NULL;

    return offset2ptr(*pval, aux->enc_offset);

}

static const ASN1_ENCODING *asn1_get_const_enc_ptr(const ASN1_VALUE **pval,

                                                   const ASN1_ITEM *it)

{

    const ASN1_AUX *aux;

    if (pval == NULL || *pval == NULL)

        return NULL;

    aux = it->funcs;

    if (aux == NULL || (aux->flags & ASN1_AFLG_ENCODING) == 0)

        return NULL;

    return offset2ptr(*pval, aux->enc_offset);

}

void ossl_asn1_enc_init(ASN1_VALUE **pval, const ASN1_ITEM *it)

{

    ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

    if (enc != NULL) {

        enc->enc = NULL;

        enc->len = 0;

        enc->modified = 1;

    }

}

void ossl_asn1_enc_free(ASN1_VALUE **pval, const ASN1_ITEM *it)

{

    ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

    if (enc != NULL) {

        OPENSSL_free(enc->enc);

        enc->enc = NULL;

        enc->len = 0;

        enc->modified = 1;

    }

}

int ossl_asn1_enc_save(ASN1_VALUE **pval, const unsigned char *in, int inlen,

                       const ASN1_ITEM *it)

{

    ASN1_ENCODING *enc = asn1_get_enc_ptr(pval, it);

    if (enc == NULL)

        return 1;

    OPENSSL_free(enc->enc);

    if (inlen <= 0)

        return 0;

    if ((enc->enc = OPENSSL_malloc(inlen)) == NULL)

        return 0;

    memcpy(enc->enc, in, inlen);

    enc->len = inlen;

    enc->modified = 0;

    return 1;

}

int ossl_asn1_enc_restore(int *len, unsigned char **out, const ASN1_VALUE **pval,

                          const ASN1_ITEM *it)

{

    const ASN1_ENCODING *enc = asn1_get_const_enc_ptr(pval, it);

    if (enc == NULL || enc->modified)

        return 0;

    if (out) {

        memcpy(*out, enc->enc, enc->len);

        *out += enc->len;

    }

    if (len != NULL)

        *len = enc->len;

    return 1;

}

/* Given an ASN1_TEMPLATE get a pointer to a field */

ASN1_VALUE **ossl_asn1_get_field_ptr(ASN1_VALUE **pval, const ASN1_TEMPLATE *tt)

{

    ASN1_VALUE **pvaltmp = offset2ptr(*pval, tt->offset);

    /*

     * NOTE for BOOLEAN types the field is just a plain int so we can't

     * return int **, so settle for (int *).

     */

    return pvaltmp;

}

/* Given an ASN1_TEMPLATE get a const pointer to a field */

const ASN1_VALUE **ossl_asn1_get_const_field_ptr(const ASN1_VALUE **pval,

                                                 const ASN1_TEMPLATE *tt)

{

    return offset2ptr(*pval, tt->offset);

}

/*

 * Handle ANY DEFINED BY template, find the selector, look up the relevant

 * ASN1_TEMPLATE in the table and return it.

 */

const ASN1_TEMPLATE *ossl_asn1_do_adb(const ASN1_VALUE *val,

                                      const ASN1_TEMPLATE *tt,

                                      int nullerr)

{

    const ASN1_ADB *adb;

    const ASN1_ADB_TABLE *atbl;

    long selector;

    const ASN1_VALUE **sfld;

    int i;

    if ((tt->flags & ASN1_TFLG_ADB_MASK) == 0)

        return tt;

    /* Else ANY DEFINED BY ... get the table */

    adb = ASN1_ADB_ptr(tt->item);

    /* Get the selector field */

    sfld = offset2ptr(val, adb->offset);

    /* Check if NULL */

    if (*sfld == NULL) {

        if (adb->null_tt == NULL)

            goto err;

        return adb->null_tt;

    }

    /*

     * Convert type to a long: NB: don't check for NID_undef here because it

     * might be a legitimate value in the table

     */

    if ((tt->flags & ASN1_TFLG_ADB_OID) != 0)

        selector = OBJ_obj2nid((ASN1_OBJECT *)*sfld);

    else

        selector = ASN1_INTEGER_get((ASN1_INTEGER *)*sfld);

    /* Let application callback translate value */

    if (adb->adb_cb != NULL && adb->adb_cb(&selector) == 0) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_UNSUPPORTED_ANY_DEFINED_BY_TYPE);

        return NULL;

    }

    /*

     * Try to find matching entry in table Maybe should check application

     * types first to allow application override? Might also be useful to

     * have a flag which indicates table is sorted and we can do a binary

     * search. For now stick to a linear search.

     */

    for (atbl = adb->tbl, i = 0; i < adb->tblcount; i++, atbl++)

        if (atbl->value == selector)

            return &atbl->tt;

    /* FIXME: need to search application table too */

    /* No match, return default type */

    if (!adb->default_tt)

        goto err;

    return adb->default_tt;

 err:

    /* FIXME: should log the value or OID of unsupported type */

    if (nullerr)

        ERR_raise(ERR_LIB_ASN1, ASN1_R_UNSUPPORTED_ANY_DEFINED_BY_TYPE);

    return NULL;

}