unber.c

RSA加密/解密算法源码 asn1c-0.9.12

/*-
 * Copyright (c) 2004 Lev Walkin <[e-mail]>. 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS 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 AUTHOR OR 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.
 *
 * $Id: unber.c,v 1.14 2005/03/10 09:33:13 vlm Exp $
 */
#include "sys-common.h"

#include <asn1parser.h>		/* For static string tables */

#include <asn_application.h>
#include <constraints.c>
#include <ber_tlv_tag.c>
#include <ber_tlv_length.c>
#include <OBJECT_IDENTIFIER.c>
#include <RELATIVE-OID.c>
#include <asn_codecs_prim.c>

#undef  COPYRIGHT
#define COPYRIGHT       \
	"Copyright (c) 2004 Lev Walkin <[e-mail]>\n"

static void usage(const char *av0);	/* Print the Usage screen and exit */
static int process(const char *fname);	/* Perform the BER decoding */
static int decode_tlv_from_string(const char *datastring);

static int single_type_decoding = 0;	/* -1 enables that */
static int pretty_printing = 1;		/* -p disables that */
static char *indent_buffer = "    ";	/* -i controls that */

int
main(int ac, char **av) {
	int ch;				/* Command line character */
	int i;				/* Index in some loops */

	/*
	 * Process command-line options.
	 */
	while((ch = getopt(ac, av, "1hi:pt:v")) != -1)
	switch(ch) {
	case '1':
		single_type_decoding = 1;
		break;
	case 't':
		if(decode_tlv_from_string(optarg))
			exit(EX_DATAERR);
		exit(0);
	case 'p':
		pretty_printing = 0;
		break;
	case 'i':
		i = atoi(optarg);
		if(i >= 0 && i < 16) {
			indent_buffer = alloca(i + 1);
			memset(indent_buffer, ' ', i);
			indent_buffer[i] = '\0';
		} else {
			fprintf(stderr, "-i %s: Invalid indent value\n",optarg);
			exit(EX_USAGE);
		}
		break;
	case 'v':
		fprintf(stderr, "ASN.1 BER Decoder, v" VERSION "\n" COPYRIGHT);
		exit(0);
		break;
	case 'h':
	default:
		usage(av[0]);
	}

	/*
	 * Ensure that there are some input files present.
	 */
	if(ac > optind) {
		ac -= optind;
		av += optind;
	} else {
		fprintf(stderr, "%s: No input files specified\n", av[0]);
		exit(1);
	}

	setvbuf(stdout, 0, _IOLBF, 0);

	/*
	 * Iterate over input files and parse each.
	 * All syntax trees from all files will be bundled together.
	 */
	for(i = 0; i < ac; i++) {
		if(process(av[i]))
			exit(EX_DATAERR);
	}

	return 0;
}

/*
 * Print the usage screen and exit(EX_USAGE).
 */
static void
usage(const char *av0) {
	fprintf(stderr,
"ASN.1 BER Decoder, v" VERSION "\n" COPYRIGHT
"Usage: %s [options] [-] [file ...]\n"
"Options:\n"
"  -1                 Decode only the first BER structure (otherwise, until EOF)\n"
"  -i <indent>        Amount of spaces for output indentation (default is 4)\n"
"  -p                 Do not attempt pretty-printing of known ASN.1 types\n"
"  -t <data-string>   Decode the given tag[/length] sequence (e.g. -t \"bf20\")\n"
"\n"
"The XML opening tag format is as follows:\n"
"  <tform T=\"tag\" TL=\"tl_len\" V=\"{Indefinite|v_len}\" [A=\"type\"] [F]>\n"
"Where:\n"
"  tform    Which form the value is in: constructed (\"C\", \"I\") or primitive (\"P\")\n"
"  tag      The tag class and value\n"
"  tl_len   The length of the TL (BER Tag and Length) encoding\n"
"  v_len    The length of the value (V, encoded by the L), may be \"Indefinite\"\n"
"  type     Likely name of the underlying ASN.1 type (for [UNIVERSAL n] tags)\n"
"  [F]      Indicates that the value was reformatted (pretty-printed)\n"
"See the manual page for details\n"
	, av0);
	exit(EX_USAGE);
}

typedef enum pd_code {
	PD_FAILED	= -1,
	PD_FINISHED	= 0,
	PD_EOF		= 1,
} pd_code_e;
static pd_code_e process_deeper(const char *fname, FILE *fp, int level, ssize_t limit, ssize_t *decoded, int expect_eoc);
static void print_TL(int fin, int level, int constr, ssize_t tlen, ber_tlv_tag_t, ber_tlv_len_t);
static int print_V(const char *fname, FILE *fp, ber_tlv_tag_t, ber_tlv_len_t);

/*
 * Open the file and initiate recursive processing.
 */
static int
process(const char *fname) {
	FILE *fp;
	pd_code_e pdc;
	ssize_t decoded = 0;

	if(strcmp(fname, "-")) {
		fp = fopen(fname, "r");
		if(!fp) {
			perror(fname);
			return -1;
		}
	} else {
		fp = stdin;
	}

	/*
	 * Fetch out BER-encoded data until EOF or error.
	 */
	do {
		pdc = process_deeper(fname, fp, 0, -1, &decoded, 0);
	} while(pdc == PD_FINISHED && !single_type_decoding);

	if(fp != stdin)
		fclose(fp);

	if(pdc == PD_FAILED)
		return -1;
	return 0;
}

/*
 * Process the TLV recursively.
 */
static pd_code_e process_deeper(const char *fname, FILE *fp, int level, ssize_t limit, ssize_t *decoded, int expect_eoc) {
	unsigned char tagbuf[32];
	ssize_t tblen = 0;
	pd_code_e pdc = PD_FINISHED;
	ber_tlv_tag_t tlv_tag;
	ber_tlv_len_t tlv_len;
	ssize_t t_len;
	ssize_t l_len;

	do {
		int constr;
		int ch;

		if(limit == 0)
			return PD_FINISHED;

		if(limit >= 0 && tblen >= limit) {
			fprintf(stderr,
				"%s: Too long TL sequence (%ld >= %ld). "
					"Dangerous file\n",
				fname, (long)tblen, (long)limit);
			return PD_FAILED;
		}

		ch = fgetc(fp);
		if(ch == -1) {
			if(tblen) {
				fprintf(stderr,
					"%s: Unexpected end of file (TL)\n",
					fname);
				return PD_FAILED;
			} else {
				return PD_EOF;
			}
		}

		tagbuf[tblen++] = ch;

		/*
		 * Decode the TLV tag.
		 */
		t_len = ber_fetch_tag(tagbuf, tblen, &tlv_tag);
		switch(t_len) {
		case -1:
			fprintf(stderr, "%s: Fatal error deciphering tag\n",
				fname);
			return PD_FAILED;
		case 0:
			/* More data expected */
			continue;
		}

		/*
		 * Decode the TLV length.
		 */
		constr = BER_TLV_CONSTRUCTED(tagbuf);
		l_len = ber_fetch_length(constr,
				tagbuf + t_len, tblen - t_len, &tlv_len);
		switch(l_len) {
		case -1:
			fprintf(stderr, "%s: Fatal error deciphering length\n",
				fname);
			return PD_FAILED;
		case 0:
			/* More data expected */
			continue;
		}

		/* Make sure the T & L decoders took exactly the whole buffer */
		assert((t_len + l_len) == tblen);

		if(!expect_eoc || tagbuf[0] || tagbuf[1])
			print_TL(0, level, constr, tblen, tlv_tag, tlv_len);

		if(limit != -1) {
			/* If limit is set, account for the TL sequence */
			limit -= (t_len + l_len);
			assert(limit >= 0);

			if(tlv_len > limit) {
				fprintf(stderr,
				"%s: Structure advertizes length (%ld) "
				"greater than of a parent container (%ld)\n",
					fname, (long)tlv_len, (long)limit);
				return PD_FAILED;
			}
		}

		*decoded += t_len + l_len;

		if(expect_eoc && tagbuf[0] == '\0' && tagbuf[1] == '\0') {
			/* End of content octets */
			print_TL(1, level - 1, 1, 2, 0, -1);
			return PD_FINISHED;
		}

		if(constr) {
			ssize_t dec = 0;
			/*
			 * This is a constructed type. Process recursively.
			 */
			printf(">\n");	/* Close the opening tag */
			if(tlv_len != -1 && limit != -1) {
				assert(limit >= tlv_len);
			}
			pdc = process_deeper(fname, fp, level + 1,
				tlv_len == -1 ? limit : tlv_len,
				&dec, tlv_len == -1);
			if(pdc == PD_FAILED) return pdc;
			if(limit != -1) {
				assert(limit >= dec);
				limit -= dec;
			}
			*decoded += dec;
			if(tlv_len == -1) {
				tblen = 0;
				continue;
			}
		} else {
			assert(tlv_len >= 0);
			if(print_V(fname, fp, tlv_tag, tlv_len))
				return PD_FAILED;

			if(limit != -1) {
				assert(limit >= tlv_len);
				limit -= tlv_len;
			}
			*decoded += tlv_len;
		}

		print_TL(1, level, constr, tblen, tlv_tag, tlv_len);

		tblen = 0;
	} while(1);

	return pdc;
}

static void
print_TL(int fin, int level, int constr, ssize_t tlen, ber_tlv_tag_t tlv_tag, ber_tlv_len_t tlv_len) {

	if(fin && !constr) {
		printf("</P>\n");
		return;
	}

	while(level-- > 0) printf(indent_buffer);  /* Print indent */
	printf(fin ? "</" : "<");

	printf(constr ? ((tlv_len == -1) ? "I" : "C") : "P");

	printf(" T=\"");
	ber_tlv_tag_fwrite(tlv_tag, stdout);
	printf("\"");

	if(!fin || tlv_len == -1)
		printf(" TL=\"%ld\"", (long)tlen);
	if(!fin) {
		if(tlv_len == -1)
			printf(" V=\"Indefinite\"");
		else
			printf(" V=\"%ld\"", (long)tlv_len);
	}