/* $OpenBSD: tasn_enc.c,v 1.34 2025/05/10 05:54:38 tb Exp $ */
/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2000.
 */
/* ====================================================================
 * Copyright (c) 2000-2004 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    licensing@OpenSSL.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <stddef.h>
#include <string.h>

#include <openssl/asn1.h>
#include <openssl/asn1t.h>
#include <openssl/objects.h>

#include "asn1_local.h"
#include "err_local.h"

static int asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
    const ASN1_ITEM *it, int tag, int aclass);
static int asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out,
    int skcontlen, const ASN1_ITEM *item, int do_sort, int iclass);
static int asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
    const ASN1_TEMPLATE *tt, int tag, int aclass);
static int asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out,
    const ASN1_ITEM *it, int flags);
static int asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
    const ASN1_ITEM *it);

/* Top level i2d equivalents: the 'ndef' variant instructs the encoder
 * to use indefinite length constructed encoding, where appropriate
 */

int
ASN1_item_ndef_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
{
        return asn1_item_flags_i2d(val, out, it, ASN1_TFLG_NDEF);
}

int
ASN1_item_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it)
{
        return asn1_item_flags_i2d(val, out, it, 0);
}
LCRYPTO_ALIAS(ASN1_item_i2d);

/* Encode an ASN1 item, this is use by the
 * standard 'i2d' function. 'out' points to
 * a buffer to output the data to.
 *
 * The new i2d has one additional feature. If the output
 * buffer is NULL (i.e. *out == NULL) then a buffer is
 * allocated and populated with the encoding.
 */

static int
asn1_item_flags_i2d(ASN1_VALUE *val, unsigned char **out, const ASN1_ITEM *it,
    int flags)
{
        unsigned char *p, *buf;
        int len;

        if (out == NULL || *out != NULL)
                return ASN1_item_ex_i2d(&val, out, it, -1, flags);

        if ((len = ASN1_item_ex_i2d(&val, NULL, it, -1, flags)) <= 0)
                return len;

        if ((buf = calloc(1, len)) == NULL)
                return -1;

        p = buf;
        if (ASN1_item_ex_i2d(&val, &p, it, -1, flags) != len) {
                freezero(buf, len);
                ASN1error(ASN1_R_LENGTH_ERROR);
                return -1;
        }

        *out = buf;

        return len;
}

/* Encode an item, taking care of IMPLICIT tagging (if any).
 * This function performs the normal item handling: it can be
 * used in external types.
 */

int
ASN1_item_ex_i2d(ASN1_VALUE **pval, unsigned char **out, const ASN1_ITEM *it,
    int tag, int aclass)
{
        const ASN1_TEMPLATE *tt = NULL;
        int i, seqcontlen, seqlen, ndef = 1;
        const ASN1_EXTERN_FUNCS *ef;
        const ASN1_AUX *aux = it->funcs;
        ASN1_aux_cb *asn1_cb = NULL;

        if ((it->itype != ASN1_ITYPE_PRIMITIVE) && !*pval)
                return 0;

        if (aux && aux->asn1_cb)
                asn1_cb = aux->asn1_cb;

        switch (it->itype) {

        case ASN1_ITYPE_PRIMITIVE:
                if (it->templates)
                        return asn1_template_ex_i2d(pval, out, it->templates,
                            tag, aclass);
                return asn1_i2d_ex_primitive(pval, out, it, tag, aclass);
                break;

        case ASN1_ITYPE_MSTRING:
                /*
                 * It never makes sense for multi-strings to have implicit
                 * tagging, so if tag != -1, then this looks like an error in
                 * the template.
                 */
                if (tag != -1) {
                        ASN1error(ASN1_R_BAD_TEMPLATE);
                        return 0;
                }
                return asn1_i2d_ex_primitive(pval, out, it, -1, aclass);

        case ASN1_ITYPE_CHOICE:
                /*
                 * It never makes sense for CHOICE types to have implicit
                 * tagging, so if tag != -1, then this looks like an error in
                 * the template.
                 */
                if (tag != -1) {
                        ASN1error(ASN1_R_BAD_TEMPLATE);
                        return 0;
                }
                if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
                        return 0;
                i = asn1_get_choice_selector(pval, it);
                if ((i >= 0) && (i < it->tcount)) {
                        ASN1_VALUE **pchval;
                        const ASN1_TEMPLATE *chtt;
                        chtt = it->templates + i;
                        pchval = asn1_get_field_ptr(pval, chtt);
                        return asn1_template_ex_i2d(pchval, out, chtt,
                            -1, aclass);
                }
                /* Fixme: error condition if selector out of range */
                if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
                        return 0;
                break;

        case ASN1_ITYPE_EXTERN:
                /* If new style i2d it does all the work */
                ef = it->funcs;
                return ef->asn1_ex_i2d(pval, out, it, tag, aclass);

        case ASN1_ITYPE_NDEF_SEQUENCE:
                /* Use indefinite length constructed if requested */
                if (aclass & ASN1_TFLG_NDEF)
                        ndef = 2;
                /* fall through */

        case ASN1_ITYPE_SEQUENCE:
                i = asn1_enc_restore(&seqcontlen, out, pval, it);
                /* An error occurred */
                if (i < 0)
                        return 0;
                /* We have a valid cached encoding... */
                if (i > 0)
                        return seqcontlen;
                /* Otherwise carry on */
                seqcontlen = 0;
                /* If no IMPLICIT tagging set to SEQUENCE, UNIVERSAL */
                if (tag == -1) {
                        tag = V_ASN1_SEQUENCE;
                        /* Retain any other flags in aclass */
                        aclass = (aclass & ~ASN1_TFLG_TAG_CLASS) |
                            V_ASN1_UNIVERSAL;
                }
                if (asn1_cb && !asn1_cb(ASN1_OP_I2D_PRE, pval, it, NULL))
                        return 0;
                /* First work out sequence content length */
                for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
                        const ASN1_TEMPLATE *seqtt;
                        ASN1_VALUE **pseqval;
                        seqtt = asn1_do_adb(pval, tt, 1);
                        if (!seqtt)
                                return 0;
                        pseqval = asn1_get_field_ptr(pval, seqtt);
                        /* FIXME: check for errors in enhanced version */
                        seqcontlen += asn1_template_ex_i2d(pseqval, NULL, seqtt,
                            -1, aclass);
                }

                seqlen = ASN1_object_size(ndef, seqcontlen, tag);
                if (!out)
                        return seqlen;
                /* Output SEQUENCE header */
                ASN1_put_object(out, ndef, seqcontlen, tag, aclass);
                for (i = 0, tt = it->templates; i < it->tcount; tt++, i++) {
                        const ASN1_TEMPLATE *seqtt;
                        ASN1_VALUE **pseqval;
                        seqtt = asn1_do_adb(pval, tt, 1);
                        if (!seqtt)
                                return 0;
                        pseqval = asn1_get_field_ptr(pval, seqtt);
                        /* FIXME: check for errors in enhanced version */
                        asn1_template_ex_i2d(pseqval, out, seqtt, -1, aclass);
                }
                if (ndef == 2)
                        ASN1_put_eoc(out);
                if (asn1_cb && !asn1_cb(ASN1_OP_I2D_POST, pval, it, NULL))
                        return 0;
                return seqlen;

        default:
                return 0;

        }
        return 0;
}
LCRYPTO_ALIAS(ASN1_item_ex_i2d);

static int
asn1_template_ex_i2d(ASN1_VALUE **pval, unsigned char **out,
    const ASN1_TEMPLATE *tt, int tag, int iclass)
{
        int i, ret, flags, ttag, tclass, ndef;
        flags = tt->flags;
        /* Work out tag and class to use: tagging may come
         * either from the template or the arguments, not both
         * because this would create ambiguity. Additionally
         * the iclass argument may contain some additional flags
         * which should be noted and passed down to other levels.
         */
        if (flags & ASN1_TFLG_TAG_MASK) {
                /* Error if argument and template tagging */
                if (tag != -1)
                        /* FIXME: error code here */
                        return -1;
                /* Get tagging from template */
                ttag = tt->tag;
                tclass = flags & ASN1_TFLG_TAG_CLASS;
        } else if (tag != -1) {
                /* No template tagging, get from arguments */
                ttag = tag;
                tclass = iclass & ASN1_TFLG_TAG_CLASS;
        } else {
                ttag = -1;
                tclass = 0;
        }
        /*
         * Remove any class mask from iflag.
         */
        iclass &= ~ASN1_TFLG_TAG_CLASS;

        /* At this point 'ttag' contains the outer tag to use,
         * 'tclass' is the class and iclass is any flags passed
         * to this function.
         */

        /* if template and arguments require ndef, use it */
        if ((flags & ASN1_TFLG_NDEF) && (iclass & ASN1_TFLG_NDEF))
                ndef = 2;
        else
                ndef = 1;

        if (flags & ASN1_TFLG_SK_MASK) {
                /* SET OF, SEQUENCE OF */
                STACK_OF(ASN1_VALUE) *sk = (STACK_OF(ASN1_VALUE) *)*pval;
                int isset, sktag, skaclass;
                int skcontlen, sklen;
                ASN1_VALUE *skitem;

                if (!*pval)
                        return 0;

                if (flags & ASN1_TFLG_SET_OF) {
                        isset = 1;
                        /* 2 means we reorder */
                        if (flags & ASN1_TFLG_SEQUENCE_OF)
                                isset = 2;
                } else
                        isset = 0;

                /* Work out inner tag value: if EXPLICIT
                 * or no tagging use underlying type.
                 */
                if ((ttag != -1) && !(flags & ASN1_TFLG_EXPTAG)) {
                        sktag = ttag;
                        skaclass = tclass;
                } else {
                        skaclass = V_ASN1_UNIVERSAL;
                        if (isset)
                                sktag = V_ASN1_SET;
                        else
                                sktag = V_ASN1_SEQUENCE;
                }

                /* Determine total length of items */
                skcontlen = 0;
                for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
                        skitem = sk_ASN1_VALUE_value(sk, i);
                        skcontlen += ASN1_item_ex_i2d(&skitem, NULL,
                            tt->item, -1, iclass);
                }
                sklen = ASN1_object_size(ndef, skcontlen, sktag);
                /* If EXPLICIT need length of surrounding tag */
                if (flags & ASN1_TFLG_EXPTAG)
                        ret = ASN1_object_size(ndef, sklen, ttag);
                else
                        ret = sklen;

                if (!out)
                        return ret;

                /* Now encode this lot... */
                /* EXPLICIT tag */
                if (flags & ASN1_TFLG_EXPTAG)
                        ASN1_put_object(out, ndef, sklen, ttag, tclass);
                /* SET or SEQUENCE and IMPLICIT tag */
                ASN1_put_object(out, ndef, skcontlen, sktag, skaclass);
                /* And the stuff itself */
                asn1_set_seq_out(sk, out, skcontlen, tt->item,
                    isset, iclass);
                if (ndef == 2) {
                        ASN1_put_eoc(out);
                        if (flags & ASN1_TFLG_EXPTAG)
                                ASN1_put_eoc(out);
                }

                return ret;
        }

        if (flags & ASN1_TFLG_EXPTAG) {
                /* EXPLICIT tagging */
                /* Find length of tagged item */
                i = ASN1_item_ex_i2d(pval, NULL, tt->item,
                    -1, iclass);
                if (!i)
                        return 0;
                /* Find length of EXPLICIT tag */
                ret = ASN1_object_size(ndef, i, ttag);
                if (out) {
                        /* Output tag and item */
                        ASN1_put_object(out, ndef, i, ttag, tclass);
                        ASN1_item_ex_i2d(pval, out, tt->item,
                            -1, iclass);
                        if (ndef == 2)
                                ASN1_put_eoc(out);
                }
                return ret;
        }

        /* Either normal or IMPLICIT tagging: combine class and flags */
        return ASN1_item_ex_i2d(pval, out, tt->item,
            ttag, tclass | iclass);
}

/* Temporary structure used to hold DER encoding of items for SET OF */

typedef struct {
        unsigned char *data;
        int length;
        ASN1_VALUE *field;
} DER_ENC;

static int
der_cmp(const void *a, const void *b)
{
        const DER_ENC *d1 = a, *d2 = b;
        int cmplen, i;

        cmplen = (d1->length < d2->length) ? d1->length : d2->length;
        i = memcmp(d1->data, d2->data, cmplen);
        if (i)
                return i;
        return d1->length - d2->length;
}

/* Output the content octets of SET OF or SEQUENCE OF */

static int
asn1_set_seq_out(STACK_OF(ASN1_VALUE) *sk, unsigned char **out, int skcontlen,
    const ASN1_ITEM *item, int do_sort, int iclass)
{
        int i;
        ASN1_VALUE *skitem;
        unsigned char *tmpdat = NULL, *p = NULL;
        DER_ENC *derlst = NULL, *tder;

        if (do_sort) {
                /* Don't need to sort less than 2 items */
                if (sk_ASN1_VALUE_num(sk) < 2)
                        do_sort = 0;
                else {
                        derlst = reallocarray(NULL, sk_ASN1_VALUE_num(sk),
                            sizeof(*derlst));
                        tmpdat = malloc(skcontlen);
                        if (!derlst || !tmpdat) {
                                free(derlst);
                                free(tmpdat);
                                return 0;
                        }
                }
        }
        /* If not sorting just output each item */
        if (!do_sort) {
                for (i = 0; i < sk_ASN1_VALUE_num(sk); i++) {
                        skitem = sk_ASN1_VALUE_value(sk, i);
                        ASN1_item_ex_i2d(&skitem, out, item, -1, iclass);
                }
                return 1;
        }
        p = tmpdat;

        /* Doing sort: build up a list of each member's DER encoding */
        for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
                skitem = sk_ASN1_VALUE_value(sk, i);
                tder->data = p;
                tder->length = ASN1_item_ex_i2d(&skitem, &p, item, -1, iclass);
                tder->field = skitem;
        }

        /* Now sort them */
        qsort(derlst, sk_ASN1_VALUE_num(sk), sizeof(*derlst), der_cmp);
        /* Output sorted DER encoding */
        p = *out;
        for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++) {
                memcpy(p, tder->data, tder->length);
                p += tder->length;
        }
        *out = p;
        /* If do_sort is 2 then reorder the STACK */
        if (do_sort == 2) {
                for (i = 0, tder = derlst; i < sk_ASN1_VALUE_num(sk); i++, tder++)
                        (void)sk_ASN1_VALUE_set(sk, i, tder->field);
        }
        free(derlst);
        free(tmpdat);
        return 1;
}

static int
asn1_i2d_ex_primitive(ASN1_VALUE **pval, unsigned char **out,
    const ASN1_ITEM *it, int tag, int aclass)
{
        int olen, len;
        int utype;
        int usetag;
        int ndef = 0;

        utype = it->utype;

        /* Get length of content octets and maybe find
         * out the underlying type.
         */

        olen = len = asn1_ex_i2c(pval, NULL, &utype, it);

        /* If SEQUENCE, SET or OTHER then header is
         * included in pseudo content octets so don't
         * include tag+length. We need to check here
         * because the call to asn1_ex_i2c() could change
         * utype.
         */
        if ((utype == V_ASN1_SEQUENCE) || (utype == V_ASN1_SET) ||
            (utype == V_ASN1_OTHER))
                usetag = 0;
        else
                usetag = 1;

        /* -1 means omit type */
        if (len == -1)
                return 0;

        /* -2 return is special meaning use ndef */
        if (len == -2) {
                ndef = 2;
                len = 0;
        }

        /* Treat any other negative value as an error. */
        if (len < 0)
                return -1;

        /* If not implicitly tagged get tag from underlying type */
        if (tag == -1)
                tag = utype;

        /* Output tag+length followed by content octets */
        if (out) {
                if (usetag)
                        ASN1_put_object(out, ndef, len, tag, aclass);
                if (asn1_ex_i2c(pval, *out, &utype, it) != olen)
                        return -1;
                if (ndef)
                        ASN1_put_eoc(out);
                else
                        *out += len;
        }

        if (usetag)
                return ASN1_object_size(ndef, len, tag);
        return len;
}

/* Produce content octets from a structure */

static int
asn1_ex_i2c(ASN1_VALUE **pval, unsigned char *cout, int *putype,
    const ASN1_ITEM *it)
{
        ASN1_BOOLEAN *tbool = NULL;
        ASN1_STRING *strtmp;
        ASN1_OBJECT *otmp;
        int utype;
        const unsigned char *cont;
        unsigned char c;
        int len;

        if (it->funcs != NULL) {
                const ASN1_PRIMITIVE_FUNCS *pf = it->funcs;

                if (pf->prim_i2c == NULL)
                        return -1;
                return pf->prim_i2c(pval, cout, putype, it);
        }

        /* Should type be omitted? */
        if ((it->itype != ASN1_ITYPE_PRIMITIVE) ||
            (it->utype != V_ASN1_BOOLEAN)) {
                if (!*pval)
                        return -1;
        }

        if (it->itype == ASN1_ITYPE_MSTRING) {
                /* If MSTRING type set the underlying type */
                strtmp = (ASN1_STRING *)*pval;
                utype = strtmp->type;
                *putype = utype;
        } else if (it->utype == V_ASN1_ANY) {
                /* If ANY set type and pointer to value */
                ASN1_TYPE *typ;
                typ = (ASN1_TYPE *)*pval;
                utype = typ->type;
                *putype = utype;
                pval = &typ->value.asn1_value;
        } else
                utype = *putype;

        switch (utype) {
        case V_ASN1_OBJECT:
                otmp = (ASN1_OBJECT *)*pval;
                cont = otmp->data;
                len = otmp->length;
                break;

        case V_ASN1_NULL:
                cont = NULL;
                len = 0;
                break;

        case V_ASN1_BOOLEAN:
                tbool = (ASN1_BOOLEAN *)pval;
                if (*tbool == -1)
                        return -1;
                if (it->utype != V_ASN1_ANY) {
                        /* Default handling if value == size field then omit */
                        if (*tbool && (it->size > 0))
                                return -1;
                        if (!*tbool && !it->size)
                                return -1;
                }
                c = (unsigned char)*tbool;
                cont = &c;
                len = 1;
                break;

        case V_ASN1_BIT_STRING:
                return i2c_ASN1_BIT_STRING((ASN1_BIT_STRING *)*pval,
                    cout ? &cout : NULL);
                break;

        case V_ASN1_INTEGER:
        case V_ASN1_ENUMERATED:
                /* These are all have the same content format
                 * as ASN1_INTEGER
                 */
                return i2c_ASN1_INTEGER((ASN1_INTEGER *)*pval,
                    cout ? &cout : NULL);
                break;

        case V_ASN1_OCTET_STRING:
        case V_ASN1_NUMERICSTRING:
        case V_ASN1_PRINTABLESTRING:
        case V_ASN1_T61STRING:
        case V_ASN1_VIDEOTEXSTRING:
        case V_ASN1_IA5STRING:
        case V_ASN1_UTCTIME:
        case V_ASN1_GENERALIZEDTIME:
        case V_ASN1_GRAPHICSTRING:
        case V_ASN1_VISIBLESTRING:
        case V_ASN1_GENERALSTRING:
        case V_ASN1_UNIVERSALSTRING:
        case V_ASN1_BMPSTRING:
        case V_ASN1_UTF8STRING:
        case V_ASN1_SEQUENCE:
        case V_ASN1_SET:
        default:
                /* All based on ASN1_STRING and handled the same */
                strtmp = (ASN1_STRING *)*pval;
                /* Special handling for NDEF */
                if ((it->size == ASN1_TFLG_NDEF) &&
                    (strtmp->flags & ASN1_STRING_FLAG_NDEF)) {
                        if (cout) {
                                strtmp->data = cout;
                                strtmp->length = 0;
                        }
                        /* Special return code */
                        return -2;
                }
                cont = strtmp->data;
                len = strtmp->length;

                break;

        }
        if (cout && len)
                memcpy(cout, cont, len);
        return len;
}