/* verify.c: The opieverify() library function.

%%% copyright-cmetz-96
This software is Copyright 1996-2001 by Craig Metz, All Rights Reserved.
The Inner Net License Version 3 applies to this software.
You should have received a copy of the license with this software. If
you didn't get a copy, you may request one from <license@inner.net>.

	History:

	Modified by cmetz for OPIE 2.4. Use struct opie_otpkey for keys.
		Check that seed and sequence number are valid.
	Modified by cmetz for OPIE 2.32. Renamed _opieparsechallenge() to
		__opieparsechallenge() and handle new argument. Fixed init
		response parsing bug.
	Modified by cmetz for OPIE 2.31. Renamed "init" to "init-hex".
	Modified by cmetz for OPIE 2.31. Renamed "init" and "RESPONSE_INIT"
		to "init-hex" and "RESPONSE_INIT_HEX". Removed active attack
		protection support.
	Created by cmetz for OPIE 2.3 using the old verify.c as a guide.
*/

#include "opie_cfg.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif /* HAVE_STRING_H */
#include <ctype.h>
#include "opie.h"

#define RESPONSE_STANDARD  0
#define RESPONSE_WORD      1
#define RESPONSE_HEX       2
#define RESPONSE_INIT_HEX  3
#define RESPONSE_INIT_WORD 4
#define RESPONSE_UNKNOWN   5

struct _rtrans {
  int type;
  char *name;
};

static struct _rtrans rtrans[] = {
  { RESPONSE_WORD, "word" },
  { RESPONSE_HEX, "hex" },
  { RESPONSE_INIT_HEX, "init-hex" },
  { RESPONSE_INIT_WORD, "init-word" },
  { RESPONSE_STANDARD, "" },
  { RESPONSE_UNKNOWN, NULL }
};

static char *algids[] = { NULL, NULL, NULL, "sha1", "md4", "md5" };

static int changed FUNCTION((opie), struct opie *opie)
{
  struct opie opie2;

  memset(&opie2, 0, sizeof(struct opie));
  opie2.opie_principal = opie->opie_principal;
  if (__opiereadrec(&opie2))
    return 1;

  if ((opie2.opie_n != opie->opie_n) || strcmp(opie2.opie_val, opie->opie_val) || strcmp(opie2.opie_seed, opie->opie_seed))
    return 1;

  memset(&opie2, 0, sizeof(struct opie));
  return 0;
}

int opieverify FUNCTION((opie, response), struct opie *opie AND char *response)
{
  int i, rval = -1;
  char *c;
  struct opie_otpkey key, fkey, lastkey;
  struct opie nopie;

  if (!opie || !response)
    goto verret;

  if (!opie->opie_principal)
#if DEBUG
    abort();
#else /* DEBUG */
    goto verret;
#endif /* DEBUG */

  if (!opieatob8(&lastkey, opie->opie_val))
    goto verret;

  for (c = opie->opie_seed; *c; c++)
    if (!isalnum(*c))
      goto verret;

  if (opie->opie_n <= 0)
    goto verret;

  if (c = strchr(response, ':')) {
    *(c++) = 0;
    {
      struct _rtrans *r;
      for (r = rtrans; r->name && strcmp(r->name, response); r++);
      i = r->type;
    }
  } else
    i = RESPONSE_STANDARD;

  switch(i) {
  case RESPONSE_STANDARD:
    i = 1;
    
    if (opieetob(&key, response) == 1) {
      memcpy(&fkey, &key, sizeof(struct opie_otpkey));
      opiehash(&fkey, MDX);
      i = memcmp(&fkey, &lastkey, sizeof(struct opie_otpkey));
    }
    if (i && opieatob8(&key, response)) {
      memcpy(&fkey, &key, sizeof(struct opie_otpkey));
      opiehash(&fkey, MDX);
      i = memcmp(&fkey, &lastkey, sizeof(struct opie_otpkey));
    }
    break;
  case RESPONSE_WORD:
    i = 1;

    if (opieetob(&key, c) == 1) {
      memcpy(&fkey, &key, sizeof(struct opie_otpkey));
      opiehash(&fkey, MDX);
      i = memcmp(&fkey, &lastkey, sizeof(struct opie_otpkey));
    }
    break;
  case RESPONSE_HEX:
    i = 1;

    if (opieatob8(&key, c)) {
      memcpy(&fkey, &key, sizeof(struct opie_otpkey));
      opiehash(&fkey, MDX);
      i = memcmp(&fkey, &lastkey, sizeof(struct opie_otpkey));
    }
    break;
  case RESPONSE_INIT_HEX:
  case RESPONSE_INIT_WORD:
    {
      char *c2;

      if (!(c2 = strchr(c, ':')))
	goto verret;

      *(c2++) = 0;

      if (i == RESPONSE_INIT_HEX) {
	if (!opieatob8(&key, c))
	  goto verret;
      } else {
	if (opieetob(&key, c) != 1)
	  goto verret;
      }

      memcpy(&fkey, &key, sizeof(struct opie_otpkey));
      opiehash(&fkey, MDX);

      if (memcmp(&fkey, &lastkey, sizeof(struct opie_otpkey)))
	goto verret;

      if (changed(opie))
	goto verret;
      
      opie->opie_n--;

      if (!opiebtoa8(opie->opie_val, &key))
	goto verret;

      if (__opiewriterec(opie))
	goto verret;

      if (!(c2 = strchr(c = c2, ':')))
	goto verret;

      *(c2++) = 0;

      {
	int j, k;

	if (__opieparsechallenge(c, &j, &(opie->opie_n), &(opie->opie_seed), &k) || (j != MDX) || k)
	  goto verret;
      }

      if (i == RESPONSE_INIT_HEX) {
	if (!opieatob8(&key, c2))
	  goto verret;
      } else {
	if (opieetob(&key, c2) != 1)
	  goto verret;
      }
    }
    goto verwrt;
  case RESPONSE_UNKNOWN:
    rval = 1;
    goto verret;
  default:
    rval = -1;
    goto verret;
  }

  if (i) {
    rval = 1;
    goto verret;
  }

  if (changed(opie))
    goto verret;
  
  opie->opie_n--;

verwrt:
  if (!opiebtoa8(opie->opie_val, &key))
    goto verret;
  rval = __opiewriterec(opie);

verret:
  opieunlock();
  memset(opie, 0, sizeof(struct opie));
  return rval;
}