heimdal/lib/asn1/gen_decode.c

/*
 * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden). 
 * 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. Neither the name of the Institute nor the names of its contributors 
 *    may be used to endorse or promote products derived from this software 
 *    without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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. 
 */

#include "gen_locl.h"

RCSID("$Id$");

static void
decode_primitive (const char *typename, const char *name)
{
    fprintf (codefile,
	     "e = decode_%s(p, len, %s, &l);\n"
	     "FORW;\n",
	     typename,
	     name);
}

static void
decode_type (const char *name, const Type *t)
{
    switch (t->type) {
    case TType:
#if 0
	decode_type (name, t->symbol->type);
#endif
	fprintf (codefile,
		 "e = decode_%s(p, len, %s, &l);\n"
		 "FORW;\n",
		 t->symbol->gen_name, name);
	break;
    case TInteger:
	if(t->members == NULL)
	    decode_primitive ("integer", name);
	else {
	    char *s;
	    asprintf(&s, "(int*)%s", name);
	    if(s == NULL)
		errx (1, "out of memory");
	    decode_primitive ("integer", s);
	    free(s);
	}
	break;
    case TUInteger:
	decode_primitive ("unsigned", name);
	break;
    case TOctetString:
	decode_primitive ("octet_string", name);
	break;
    case TBitString: {
	Member *m;
	int tag = -1;
	int pos;

	fprintf (codefile,
		 "e = der_match_tag_and_length (p, len, UNIV, PRIM, UT_BitString,"
		 "&reallen, &l);\n"
		 "FORW;\n"
		 "if(len < reallen)\n"
		 "return ASN1_OVERRUN;\n"
		 "p++;\n"
		 "len--;\n"
		 "reallen--;\n"
		 "ret++;\n");
	pos = 0;
	for (m = t->members; m && tag != m->val; m = m->next) {
	    while (m->val / 8 > pos / 8) {
		fprintf (codefile,
			 "p++; len--; reallen--; ret++;\n");
		pos += 8;
	    }
	    fprintf (codefile,
		     "%s->%s = (*p >> %d) & 1;\n",
		     name, m->gen_name, 7 - m->val % 8);
	    if (tag == -1)
		tag = m->val;
	}
	fprintf (codefile,
		 "p += reallen; len -= reallen; ret += reallen;\n");
	break;
    }
    case TSequence: {
	Member *m;
	int tag = -1;

	if (t->members == NULL)
	    break;

	fprintf (codefile,
		 "e = der_match_tag_and_length (p, len, UNIV, CONS, UT_Sequence,"
		 "&reallen, &l);\n"
		 "FORW;\n"
		 "{\n"
		 "int dce_fix;\n"
		 "if((dce_fix = fix_dce(reallen, &len)) < 0)\n"
		 "return ASN1_BAD_FORMAT;\n");

	for (m = t->members; m && tag != m->val; m = m->next) {
	    char *s;

	    asprintf (&s, "%s(%s)->%s", m->optional ? "" : "&", name, m->gen_name);
	    if (0 && m->type->type == TType){
		if(m->optional)
		    fprintf (codefile,
			     "%s = malloc(sizeof(*%s));\n"
			     "if(%s == NULL) return ENOMEM;\n", s, s, s);
		fprintf (codefile, 
			 "e = decode_seq_%s(p, len, %d, %d, %s, &l);\n",
			 m->type->symbol->gen_name,
			 m->val, 
			 m->optional,
			 s);
		if(m->optional)
		    fprintf (codefile, 
			     "if (e == ASN1_MISSING_FIELD) {\n"
			     "free(%s);\n"
			     "%s = NULL;\n"
			     "e = l = 0;\n"
			     "}\n",
			     s, s);
	  
		fprintf (codefile, "FORW;\n");
	  
	    }else{
		fprintf (codefile, "{\n"
			 "size_t newlen, oldlen;\n\n"
			 "e = der_match_tag (p, len, CONTEXT, CONS, %d, &l);\n",
			 m->val);
		fprintf (codefile,
			 "if (e)\n");
		if(m->optional)
		    /* XXX should look at e */
		    fprintf (codefile,
			     "%s = NULL;\n", s);
		else
		    fprintf (codefile,
			     "return e;\n");
		fprintf (codefile, 
			 "else {\n");
		fprintf (codefile,
			 "p += l;\n"
			 "len -= l;\n"
			 "ret += l;\n"
			 "e = der_get_length (p, len, &newlen, &l);\n"
			 "FORW;\n"
			 "{\n"
	       
			 "int dce_fix;\n"
			 "oldlen = len;\n"
			 "if((dce_fix = fix_dce(newlen, &len)) < 0)"
			 "return ASN1_BAD_FORMAT;\n");
		if (m->optional)
		    fprintf (codefile,
			     "%s = malloc(sizeof(*%s));\n"
			     "if(%s == NULL) return ENOMEM;\n", s, s, s);
		decode_type (s, m->type);
		fprintf (codefile,
			 "if(dce_fix){\n"
			 "e = der_match_tag_and_length (p, len, "
			 "(Der_class)0, (Der_type)0, 0, &reallen, &l);\n"
			 "FORW;\n"
			 "}else \n"
			 "len = oldlen - newlen;\n"
			 "}\n"
			 "}\n");
		fprintf (codefile,
			 "}\n");
	    }
	    if (tag == -1)
		tag = m->val;
	    free (s);
	}
	fprintf(codefile,
		"if(dce_fix){\n"
		"e = der_match_tag_and_length (p, len, "
		"(Der_class)0, (Der_type)0, 0, &reallen, &l);\n"
		"FORW;\n"
		"}\n"
		"}\n");

	break;
    }
    case TSequenceOf: {
	char *n;

	fprintf (codefile,
		 "e = der_match_tag_and_length (p, len, UNIV, CONS, UT_Sequence,"
		 "&reallen, &l);\n"
		 "FORW;\n"
		 "if(len < reallen)\n"
		 "return ASN1_OVERRUN;\n"
		 "len = reallen;\n");

	fprintf (codefile,
		 "{\n"
		 "size_t origlen = len;\n"
		 "int oldret = ret;\n"
		 "ret = 0;\n"
		 "(%s)->len = 0;\n"
		 "(%s)->val = NULL;\n"
		 "while(ret < origlen) {\n"
		 "(%s)->len++;\n"
		 "(%s)->val = realloc((%s)->val, sizeof(*((%s)->val)) * (%s)->len);\n",
		 name, name, name, name, name, name, name);
	asprintf (&n, "&(%s)->val[(%s)->len-1]", name, name);
	decode_type (n, t->subtype);
	fprintf (codefile, 
		 "len = origlen - ret;\n"
		 "}\n"
		 "ret += oldret;\n"
		 "}\n");
	free (n);
	break;
    }
    case TGeneralizedTime:
	decode_primitive ("generalized_time", name);
	break;
    case TGeneralString:
	decode_primitive ("general_string", name);
	break;
    case TApplication:
	fprintf (codefile,
		 "e = der_match_tag_and_length (p, len, APPL, CONS, %d, "
		 "&reallen, &l);\n"
		 "FORW;\n"
		 "{\n"
		 "int dce_fix;\n"
		 "if((dce_fix = fix_dce(reallen, &len)) < 0)\n"
		 "return ASN1_BAD_FORMAT;\n", 
		 t->application);
	decode_type (name, t->subtype);
	fprintf(codefile,
		"if(dce_fix){\n"
		"e = der_match_tag_and_length (p, len, "
		"(Der_class)0, (Der_type)0, 0, &reallen, &l);\n"
		"FORW;\n"
		"}\n"
		"}\n");

	break;
    default :
	abort ();
    }
}

void
generate_type_decode (const Symbol *s)
{
  fprintf (headerfile,
	   "int    "
	   "decode_%s(const unsigned char *, size_t, %s *, size_t *);\n",
	   s->gen_name, s->gen_name);

  fprintf (codefile, "#define FORW "
	   "if(e) goto fail; "
	   "p += l; "
	   "len -= l; "
	   "ret += l\n\n");


  fprintf (codefile, "int\n"
	   "decode_%s(const unsigned char *p,"
	   " size_t len, %s *data, size_t *size)\n"
	   "{\n",
	   s->gen_name, s->gen_name);

  switch (s->type->type) {
  case TInteger:
  case TUInteger:
  case TOctetString:
  case TGeneralizedTime:
  case TGeneralString:
  case TBitString:
  case TSequence:
  case TSequenceOf:
  case TApplication:
  case TType:
    fprintf (codefile,
	     "size_t ret = 0, reallen;\n"
	     "size_t l;\n"
	     "int i, e;\n\n");
    fprintf (codefile, "memset(data, 0, sizeof(*data));\n");
    fprintf (codefile, "i = 0;\n"); /* hack to avoid `unused variable' */
    fprintf (codefile, "reallen = 0;\n"); /* hack to avoid `unused variable' */

    decode_type ("data", s->type);
    fprintf (codefile, 
	     "if(size) *size = ret;\n"
	     "return 0;\n");
    fprintf (codefile,
	     "fail:\n"
	     "free_%s(data);\n"
	     "return e;\n",
	     s->gen_name);
    break;
  default:
    abort ();
  }
  fprintf (codefile, "}\n\n");
}

void
generate_seq_type_decode (const Symbol *s)
{
    fprintf (headerfile,
	     "int decode_seq_%s(const unsigned char *, size_t, int, int, "
	     "%s *, size_t *);\n",
	     s->gen_name, s->gen_name);

    fprintf (codefile, "int\n"
	     "decode_seq_%s(const unsigned char *p, size_t len, int tag, "
	     "int optional, %s *data, size_t *size)\n"
	     "{\n",
	     s->gen_name, s->gen_name);

    fprintf (codefile,
	     "size_t newlen, oldlen;\n"
	     "size_t l, ret = 0;\n"
	     "int e;\n"
	     "int dce_fix;\n");
    
    fprintf (codefile,
	     "e = der_match_tag(p, len, CONTEXT, CONS, tag, &l);\n"
	     "if (e)\n"
	     "return e;\n");
    fprintf (codefile, 
	     "p += l;\n"
	     "len -= l;\n"
	     "ret += l;\n"
	     "e = der_get_length(p, len, &newlen, &l);\n"
	     "if (e)\n"
	     "return e;\n"
	     "p += l;\n"
	     "len -= l;\n"
	     "ret += l;\n"
	     "oldlen = len;\n"
	     "if ((dce_fix = fix_dce(newlen, &len)) < 0)\n"
	     "return ASN1_BAD_FORMAT;\n"
	     "e = decode_%s(p, len, data, &l);\n"
	     "if (e)\n"
	     "return e;\n"
	     "p += l;\n"
	     "len -= l;\n"
	     "ret += l;\n"
	     "if (dce_fix) {\n"
	     "size_t reallen;\n\n"
	     "e = der_match_tag_and_length(p, len, "
	     "(Der_class)0, (Der_type)0, 0, &reallen, &l);\n"
	     "if (e)\n"
	     "return e;\n"
	     "ret += l;\n"
	     "}\n",
	     s->gen_name);
    fprintf (codefile, 
	     "if(size) *size = ret;\n"
	     "return 0;\n");

    fprintf (codefile, "}\n\n");
}