/* $OpenBSD: asn1_types.c,v 1.3 2023/07/05 21:23:36 beck Exp $ */
/*
 * Copyright (c) 2021 Joel Sing <jsing@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <stddef.h>

#include <openssl/asn1.h>

#define ASN1_ENCODING_CONSTRUCTED_ONLY  1
#define ASN1_ENCODING_PRIMITIVE_ONLY    2

struct asn1_type {
        const char *name;
        uint32_t bit_value;
        int char_width;
        int encoding;
};

/*
 * Universal class tag types - ITU X.680.
 */
static const struct asn1_type asn1_types[31] = {
        [0] = {
                /* Tag 0 (0x00) - Reserved for use by encoding rules */
                .name = "EOC",
                .bit_value = 0,
                .char_width = -1,
        },
        [1] = {
                /* Tag 1 (0x01) - Boolean */
                .name = "BOOLEAN",
                .bit_value = 0,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [2] = {
                /* Tag 2 (0x02) - Integer */
                .name = "INTEGER",
                .bit_value = 0,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [3] = {
                /* Tag 3 (0x03) - BitString */
                .name = "BIT STRING",
                .bit_value = B_ASN1_BIT_STRING,
                .char_width = -1,
        },
        [4] = {
                /* Tag 4 (0x04) - OctetString */
                .name = "OCTET STRING",
                .bit_value = B_ASN1_OCTET_STRING,
                .char_width = -1,
        },
        [5] = {
                /* Tag 5 (0x05) - Null */
                .name = "NULL",
                .bit_value = 0,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [6] = {
                /* Tag 6 (0x06) - Object Identifier */
                .name = "OBJECT",
                .bit_value = 0,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [7] = {
                /* Tag 7 (0x07) - Object Descriptor */
                .name = "OBJECT DESCRIPTOR",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
        },
        [8] = {
                /* Tag 8 (0x08) - External */
                .name = "EXTERNAL",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
        },
        [9] = {
                /* Tag 9 (0x09) - Real */
                .name = "REAL",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [10] = {
                /* Tag 10 (0x0a) - Enumerated */
                .name = "ENUMERATED",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [11] = {
                /* Tag 11 (0x0b) - Embedded PDV */
                .name = "<ASN1 11 EMBEDDED PDV>",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
        },
        [12] = {
                /* Tag 12 (0x0c) - UTF8String */
                .name = "UTF8STRING",
                .bit_value = B_ASN1_UTF8STRING,
                .char_width = 0,
        },
        [13] = {
                /* Tag 13 (0x0d) - Relative Object Identifier */
                .name = "<ASN1 13 RELATIVE OID>",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [14] = {
                /* Tag 14 (0x0e) - Time */
                .name = "<ASN1 14 TIME>",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
                .encoding = ASN1_ENCODING_PRIMITIVE_ONLY,
        },
        [15] = {
                /* Tag 15 (0x0f) - Reserved */
                .name = "<ASN1 15 RESERVED>",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
        },
        [16] = {
                /* Tag 16 (0x10)- Sequence */
                .name = "SEQUENCE",
                .bit_value = B_ASN1_SEQUENCE,
                .char_width = -1,
                .encoding = ASN1_ENCODING_CONSTRUCTED_ONLY,
        },
        [17] = {
                /* Tag 17 (0x11) - Set */
                .name = "SET",
                .bit_value = 0,
                .char_width = -1,
                .encoding = ASN1_ENCODING_CONSTRUCTED_ONLY,
        },
        [18] = {
                /* Tag 18 (0x12) - NumericString */
                .name = "NUMERICSTRING",
                .bit_value = B_ASN1_NUMERICSTRING,
                .char_width = -1,
        },
        [19] = {
                /* Tag 19 (0x13) - PrintableString */
                .name = "PRINTABLESTRING",
                .bit_value = B_ASN1_PRINTABLESTRING,
                .char_width = 1,
        },
        [20] = {
                /* Tag 20 (0x14) - TeletexString (T61String) */
                .name = "T61STRING",
                .bit_value = B_ASN1_T61STRING,
                .char_width = 1,
        },
        [21] = {
                /* Tag 21 (0x15) - VideotexString */
                .name = "VIDEOTEXSTRING",
                .bit_value = B_ASN1_VIDEOTEXSTRING,
                .char_width = -1,
        },
        [22] = {
                /* Tag 22 (0x16) - IA5String */
                .name = "IA5STRING",
                .bit_value = B_ASN1_IA5STRING,
                .char_width = 1,
        },
        [23] = {
                /* Tag 23 (0x17) - UTCTime */
                .name = "UTCTIME",
                .bit_value = B_ASN1_UTCTIME,
                .char_width = 1,
        },
        [24] = {
                /* Tag 24 (0x18) - GeneralizedTime */
                .name = "GENERALIZEDTIME",
                .bit_value = B_ASN1_GENERALIZEDTIME,
                .char_width = 1,
        },
        [25] = {
                /* Tag 25 (0x19) - GraphicString */
                .name = "GRAPHICSTRING",
                .bit_value = B_ASN1_GRAPHICSTRING,
                .char_width = -1,
        },
        [26] = {
                /* Tag 26 (0x1a) - VisibleString (ISO646String) */
                .name = "VISIBLESTRING",
                .bit_value = B_ASN1_ISO64STRING,
                .char_width = 1,
        },
        [27] = {
                /* Tag 27 (0x1b) - GeneralString */
                .name = "GENERALSTRING",
                .bit_value = B_ASN1_GENERALSTRING,
                .char_width = -1,
        },
        [28] = {
                /* Tag 28 (0x1c) - UniversalString */
                .name = "UNIVERSALSTRING",
                .bit_value = B_ASN1_UNIVERSALSTRING,
                .char_width = 4,
        },
        [29] = {
                /* Tag 29 (0x1d) - Unallocated */
                .name = "<ASN1 29>",
                .bit_value = B_ASN1_UNKNOWN,
                .char_width = -1,
        },
        [30] = {
                /* Tag 30 (0x1e) - BMPString */
                .name = "BMPSTRING",
                .bit_value = B_ASN1_BMPSTRING,
                .char_width = 2,
        },
};

static const struct asn1_type *
asn1_type_by_tag(int tag)
{
        if (tag < 0 || tag > 30)
                return NULL;

        return &asn1_types[tag];
}

int
asn1_must_be_constructed(int tag)
{
        const struct asn1_type *at;

        if (tag == V_ASN1_NEG_INTEGER || tag == V_ASN1_NEG_ENUMERATED)
                tag &= ~V_ASN1_NEG;
        if ((at = asn1_type_by_tag(tag)) != NULL)
                return at->encoding == ASN1_ENCODING_CONSTRUCTED_ONLY;

        return 0;
}

int
asn1_must_be_primitive(int tag)
{
        const struct asn1_type *at;

        if (tag == V_ASN1_NEG_INTEGER || tag == V_ASN1_NEG_ENUMERATED)
                tag &= ~V_ASN1_NEG;
        if ((at = asn1_type_by_tag(tag)) != NULL)
                return at->encoding == ASN1_ENCODING_PRIMITIVE_ONLY;

        return 0;
}

int
asn1_tag2charwidth(int tag)
{
        const struct asn1_type *at;

        if ((at = asn1_type_by_tag(tag)) != NULL)
                return at->char_width;

        return -1;
}

unsigned long
ASN1_tag2bit(int tag)
{
        const struct asn1_type *at;

        if ((at = asn1_type_by_tag(tag)) != NULL)
                return (unsigned long)at->bit_value;

        return 0;
}
LCRYPTO_ALIAS(ASN1_tag2bit);

const char *
ASN1_tag2str(int tag)
{
        const struct asn1_type *at;

        if (tag == V_ASN1_NEG_INTEGER || tag == V_ASN1_NEG_ENUMERATED)
                tag &= ~V_ASN1_NEG;

        if ((at = asn1_type_by_tag(tag)) != NULL)
                return at->name;

        return "(unknown)";
}
LCRYPTO_ALIAS(ASN1_tag2str);