/*

 * Copyright 1995-2019 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the OpenSSL license (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 <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "apps.h"

#include "progs.h"

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/x509.h>

#include <openssl/pem.h>

#include <openssl/asn1t.h>

typedef enum OPTION_choice {

    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,

    OPT_INFORM, OPT_IN, OPT_OUT, OPT_INDENT, OPT_NOOUT,

    OPT_OID, OPT_OFFSET, OPT_LENGTH, OPT_DUMP, OPT_DLIMIT,

    OPT_STRPARSE, OPT_GENSTR, OPT_GENCONF, OPT_STRICTPEM,

    OPT_ITEM

} OPTION_CHOICE;

const OPTIONS asn1parse_options[] = {

    {"help", OPT_HELP, '-', "Display this summary"},

    {"inform", OPT_INFORM, 'F', "input format - one of DER PEM"},

    {"in", OPT_IN, '<', "input file"},

    {"out", OPT_OUT, '>', "output file (output format is always DER)"},

    {"i", OPT_INDENT, 0, "indents the output"},

    {"noout", OPT_NOOUT, 0, "do not produce any output"},

    {"offset", OPT_OFFSET, 'p', "offset into file"},

    {"length", OPT_LENGTH, 'p', "length of section in file"},

    {"oid", OPT_OID, '<', "file of extra oid definitions"},

    {"dump", OPT_DUMP, 0, "unknown data in hex form"},

    {"dlimit", OPT_DLIMIT, 'p',

     "dump the first arg bytes of unknown data in hex form"},

    {"strparse", OPT_STRPARSE, 'p',

     "offset; a series of these can be used to 'dig'"},

    {OPT_MORE_STR, 0, 0, "into multiple ASN1 blob wrappings"},

    {"genstr", OPT_GENSTR, 's', "string to generate ASN1 structure from"},

    {"genconf", OPT_GENCONF, 's', "file to generate ASN1 structure from"},

    {OPT_MORE_STR, 0, 0, "(-inform  will be ignored)"},

    {"strictpem", OPT_STRICTPEM, 0,

     "do not attempt base64 decode outside PEM markers"},

    {"item", OPT_ITEM, 's', "item to parse and print"},

    {NULL}

};

static int do_generate(char *genstr, const char *genconf, BUF_MEM *buf);

int asn1parse_main(int argc, char **argv)

{

    ASN1_TYPE *at = NULL;

    BIO *in = NULL, *b64 = NULL, *derout = NULL;

    BUF_MEM *buf = NULL;

    STACK_OF(OPENSSL_STRING) *osk = NULL;

    char *genstr = NULL, *genconf = NULL;

    char *infile = NULL, *oidfile = NULL, *derfile = NULL;

    unsigned char *str = NULL;

    char *name = NULL, *header = NULL, *prog;

    const unsigned char *ctmpbuf;

    int indent = 0, noout = 0, dump = 0, strictpem = 0, informat = FORMAT_PEM;

    int offset = 0, ret = 1, i, j;

    long num, tmplen;

    unsigned char *tmpbuf;

    unsigned int length = 0;

    OPTION_CHOICE o;

    const ASN1_ITEM *it = NULL;

    prog = opt_init(argc, argv, asn1parse_options);

    if ((osk = sk_OPENSSL_STRING_new_null()) == NULL) {

        BIO_printf(bio_err, "%s: Memory allocation failure\n", prog);

        goto end;

    }

    while ((o = opt_next()) != OPT_EOF) {

        switch (o) {

        case OPT_EOF:

        case OPT_ERR:

 opthelp:

            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);

            goto end;

        case OPT_HELP:

            opt_help(asn1parse_options);

            ret = 0;

            goto end;

        case OPT_INFORM:

            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &informat))

                goto opthelp;

            break;

        case OPT_IN:

            infile = opt_arg();

            break;

        case OPT_OUT:

            derfile = opt_arg();

            break;

        case OPT_INDENT:

            indent = 1;

            break;

        case OPT_NOOUT:

            noout = 1;

            break;

        case OPT_OID:

            oidfile = opt_arg();

            break;

        case OPT_OFFSET:

            offset = strtol(opt_arg(), NULL, 0);

            break;

        case OPT_LENGTH:

            length = strtol(opt_arg(), NULL, 0);

            break;

        case OPT_DUMP:

            dump = -1;

            break;

        case OPT_DLIMIT:

            dump = strtol(opt_arg(), NULL, 0);

            break;

        case OPT_STRPARSE:

            sk_OPENSSL_STRING_push(osk, opt_arg());

            break;

        case OPT_GENSTR:

            genstr = opt_arg();

            break;

        case OPT_GENCONF:

            genconf = opt_arg();

            break;

        case OPT_STRICTPEM:

            strictpem = 1;

            informat = FORMAT_PEM;

            break;

        case OPT_ITEM:

            it = ASN1_ITEM_lookup(opt_arg());

            if (it == NULL) {

                size_t tmp;

                BIO_printf(bio_err, "Unknown item name %s\n", opt_arg());

                BIO_puts(bio_err, "Supported types:\n");

                for (tmp = 0;; tmp++) {

                    it = ASN1_ITEM_get(tmp);

                    if (it == NULL)

                        break;

                    BIO_printf(bio_err, "    %s\n", it->sname);

                }

                goto end;

            }

            break;

        }

    }

    argc = opt_num_rest();

    if (argc != 0)

        goto opthelp;

    if (oidfile != NULL) {

        in = bio_open_default(oidfile, 'r', FORMAT_TEXT);

        if (in == NULL)

            goto end;

        OBJ_create_objects(in);

        BIO_free(in);

    }

    if ((in = bio_open_default(infile, 'r', informat)) == NULL)

        goto end;

    if (derfile && (derout = bio_open_default(derfile, 'w', FORMAT_ASN1)) == NULL)

        goto end;

    if ((buf = BUF_MEM_new()) == NULL)

        goto end;

    if (strictpem) {

        if (PEM_read_bio(in, &name, &header, &str, &num) != 1) {

            BIO_printf(bio_err, "Error reading PEM file\n");

            ERR_print_errors(bio_err);

            goto end;

        }

        buf->data = (char *)str;

        buf->length = buf->max = num;

    } else {

        if (!BUF_MEM_grow(buf, BUFSIZ * 8))

            goto end;           /* Pre-allocate :-) */

        if (genstr || genconf) {

            num = do_generate(genstr, genconf, buf);

            if (num < 0) {

                ERR_print_errors(bio_err);

                goto end;

            }

        } else {

            if (informat == FORMAT_PEM) {

                BIO *tmp;

                if ((b64 = BIO_new(BIO_f_base64())) == NULL)

                    goto end;

                BIO_push(b64, in);

                tmp = in;

                in = b64;

                b64 = tmp;

            }

            num = 0;

            for (;;) {

                if (!BUF_MEM_grow(buf, num + BUFSIZ))

                    goto end;

                i = BIO_read(in, &(buf->data[num]), BUFSIZ);

                if (i <= 0)

                    break;

                num += i;

            }

        }

        str = (unsigned char *)buf->data;

    }

    /* If any structs to parse go through in sequence */

    if (sk_OPENSSL_STRING_num(osk)) {

        tmpbuf = str;

        tmplen = num;

        for (i = 0; i < sk_OPENSSL_STRING_num(osk); i++) {

            ASN1_TYPE *atmp;

            int typ;

            j = strtol(sk_OPENSSL_STRING_value(osk, i), NULL, 0);

            if (j <= 0 || j >= tmplen) {

                BIO_printf(bio_err, "'%s' is out of range\n",

                           sk_OPENSSL_STRING_value(osk, i));

                continue;

            }

            tmpbuf += j;

            tmplen -= j;

            atmp = at;

            ctmpbuf = tmpbuf;

            at = d2i_ASN1_TYPE(NULL, &ctmpbuf, tmplen);

            ASN1_TYPE_free(atmp);

            if (!at) {

                BIO_printf(bio_err, "Error parsing structure\n");

                ERR_print_errors(bio_err);

                goto end;

            }

            typ = ASN1_TYPE_get(at);

            if ((typ == V_ASN1_OBJECT)

                || (typ == V_ASN1_BOOLEAN)

                || (typ == V_ASN1_NULL)) {

                BIO_printf(bio_err, "Can't parse %s type\n", ASN1_tag2str(typ));

                ERR_print_errors(bio_err);

                goto end;

            }

            /* hmm... this is a little evil but it works */

            tmpbuf = at->value.asn1_string->data;

            tmplen = at->value.asn1_string->length;

        }

        str = tmpbuf;

        num = tmplen;

    }

    if (offset < 0 || offset >= num) {

        BIO_printf(bio_err, "Error: offset out of range\n");

        goto end;

    }

    num -= offset;

    if (length == 0 || length > (unsigned int)num)

        length = (unsigned int)num;

    if (derout != NULL) {

        if (BIO_write(derout, str + offset, length) != (int)length) {

            BIO_printf(bio_err, "Error writing output\n");

            ERR_print_errors(bio_err);

            goto end;

        }

    }

    if (!noout) {

        const unsigned char *p = str + offset;

        if (it != NULL) {

            ASN1_VALUE *value = ASN1_item_d2i(NULL, &p, length, it);

            if (value == NULL) {

                BIO_printf(bio_err, "Error parsing item %s\n", it->sname);

                ERR_print_errors(bio_err);

                goto end;

            }

            ASN1_item_print(bio_out, value, 0, it, NULL);

            ASN1_item_free(value, it);

        } else {

            if (!ASN1_parse_dump(bio_out, p, length, indent, dump)) {

                ERR_print_errors(bio_err);

                goto end;

            }

        }

    }

    ret = 0;

 end:

    BIO_free(derout);

    BIO_free(in);

    BIO_free(b64);

    if (ret != 0)

        ERR_print_errors(bio_err);

    BUF_MEM_free(buf);

    OPENSSL_free(name);

    OPENSSL_free(header);

    ASN1_TYPE_free(at);

    sk_OPENSSL_STRING_free(osk);

    return ret;

}

static int do_generate(char *genstr, const char *genconf, BUF_MEM *buf)

{

    CONF *cnf = NULL;

    int len;

    unsigned char *p;

    ASN1_TYPE *atyp = NULL;

    if (genconf != NULL) {

        if ((cnf = app_load_config(genconf)) == NULL)

            goto err;

        if (genstr == NULL)

            genstr = NCONF_get_string(cnf, "default", "asn1");

        if (genstr == NULL) {

            BIO_printf(bio_err, "Can't find 'asn1' in '%s'\n", genconf);

            goto err;

        }

    }

    atyp = ASN1_generate_nconf(genstr, cnf);

    NCONF_free(cnf);

    cnf = NULL;

    if (atyp == NULL)

        return -1;

    len = i2d_ASN1_TYPE(atyp, NULL);

    if (len <= 0)

        goto err;

    if (!BUF_MEM_grow(buf, len))

        goto err;

    p = (unsigned char *)buf->data;

    i2d_ASN1_TYPE(atyp, &p);

    ASN1_TYPE_free(atyp);

    return len;

 err:

    NCONF_free(cnf);

    ASN1_TYPE_free(atyp);

    return -1;

}