scyther/src/claim.c

/**
 *
 *@file claim.c
 *
 * Claim handling for the Arachne engine.
 *
 */

#include <stdlib.h>

#include "termmap.h"
#include "system.h"
#include "label.h"
#include "error.h"
#include "debug.h"
#include "binding.h"
#include "arachne.h"
#include "specialterm.h"
#include "switches.h"
#include "memory.h"

//! When none of the runs match
#define MATCH_NONE 0
//! When the order matches
#define MATCH_ORDER 1
//! When the order is reversed
#define MATCH_REVERSE 2
//! When the content matches
#define MATCH_CONTENT 3

//! This label is fixed
#define LABEL_GOOD -3
//! This label still needs to be done
#define LABEL_TODO -2

extern int globalError;
extern int attack_leastcost;

// Debugging the NI-SYNCH checks
//#define OKIDEBUG

/*
 * Validity checks for claims
 *
 * Note that the first few operate on claims, and that the tests for e.g. the Arachne engine are seperate.
 */


#ifdef OKIDEBUG
int indac = 0;

void
indact ()
{
  int i;

  i = indac;
  while (i > 0)
    {
      printf ("|   ");
      i--;
    }
}
#endif

//! Check complete message match
/**
 * Roledef based.
 *@returns MATCH_NONE or MATCH_CONTENT
 */
__inline__ int
events_match_rd (const Roledef rdi, const Roledef rdj)
{
  if (isTermEqual (rdi->message, rdj->message) &&
      isTermEqual (rdi->from, rdj->from) &&
      isTermEqual (rdi->to, rdj->to) &&
      isTermEqual (rdi->label, rdj->label) &&
      !(rdi->internal || rdj->internal))
    {
      return MATCH_CONTENT;
    }
  else
    {
      return MATCH_NONE;
    }
}


//! Check complete message match
/**
 *@returns any of the MATCH_ signals
 */
__inline__ int
events_match (const System sys, const int i, const int j)
{
  Roledef rdi, rdj;

  rdi = sys->traceEvent[i];
  rdj = sys->traceEvent[j];
  if (isTermEqual (rdi->message, rdj->message) &&
      isTermEqual (rdi->from, rdj->from) &&
      isTermEqual (rdi->to, rdj->to) &&
      isTermEqual (rdi->label, rdj->label) &&
      !(rdi->internal || rdj->internal))
    {
      if (rdi->type == SEND && rdj->type == READ)
	{
	  if (i < j)
	    return MATCH_ORDER;
	  else
	    return MATCH_REVERSE;
	}
      if (rdi->type == READ && rdj->type == SEND)
	{
	  if (i > j)
	    return MATCH_ORDER;
	  else
	    return MATCH_REVERSE;
	}
    }
  return MATCH_NONE;
}


//! Check nisynch from label_to_index.
__inline__ int
oki_nisynch_full (const System sys, const Termmap label_to_index)
{
  // Are all labels well linked?
  Termmap label_to_index_scan;

  label_to_index_scan = label_to_index;
  while (label_to_index_scan != NULL)
    {
      if (label_to_index_scan->result != LABEL_GOOD)
	{
#ifdef OKIDEBUG
	  indact ();
	  printf ("Incorrectly linked label at the end,");
	  printf ("label: ");
	  termPrint (label_to_index_scan->term);
	  printf ("\n");
#endif
	  return 0;
	}
      label_to_index_scan = label_to_index_scan->next;
    }
  // Apparently they are all well linked
  return 1;
}

//! Evaluate claims or internal reads (chooses)
__inline__ int
oki_nisynch_other (const System sys, const int trace_index,
		   const Termmap role_to_run, const Termmap label_to_index)
{
  int result;

#ifdef OKIDEBUG
  indact ();
  printf ("Exploring further assuming this (claim) run is not involved.\n");
  indac++;
#endif
  result = oki_nisynch (sys, trace_index - 1, role_to_run, label_to_index);
#ifdef OKIDEBUG
  indact ();
  printf (">%i<\n", result);
  indac--;
#endif
  return result;
}

//! Evaluate reads
__inline__ int
oki_nisynch_read (const System sys, const int trace_index,
		  const Termmap role_to_run, const Termmap label_to_index)
{
  /*
   * Read is only relevant for already involved runs, and labels in prec
   */
  Termmap role_to_run_scan;
  int result = 7;
  Roledef rd;
  int rid;

  rd = sys->traceEvent[trace_index];
  rid = sys->traceRun[trace_index];

  role_to_run_scan = role_to_run;
  while (role_to_run_scan != NULL)
    {
      if (role_to_run_scan->result == rid)
	{
	  // Involved, but is it a prec label?
	  if (termmapGet (label_to_index, rd->label) == LABEL_TODO)
	    {
	      Termmap label_to_index_buf;
	      int result;

	      label_to_index_buf = termmapDuplicate (label_to_index);
	      label_to_index_buf =
		termmapSet (label_to_index_buf, rd->label, trace_index);
#ifdef OKIDEBUG
	      indact ();
	      printf ("Exploring because this (read) run is involved.\n");
	      indac++;
#endif
	      result =
		oki_nisynch (sys, trace_index - 1, role_to_run,
			     label_to_index_buf);
#ifdef OKIDEBUG
	      indact ();
	      printf (">%i<\n", result);
	      indac--;
#endif
	      termmapDelete (label_to_index_buf);
	      return result;
	    }
	}
      role_to_run_scan = role_to_run_scan->next;
    }
  // Apparently not involved
#ifdef OKIDEBUG
  indact ();
  printf ("Exploring further assuming this (read) run is not involved.\n");
  indac++;
#endif
  result = oki_nisynch (sys, trace_index - 1, role_to_run, label_to_index);
#ifdef OKIDEBUG
  indac--;
#endif
  return result;
}


//! Evaluate sends
__inline__ int
oki_nisynch_send (const System sys, const int trace_index,
		  const Termmap role_to_run, const Termmap label_to_index)
{
  Roledef rd;
  int rid;
  int result = 8;
  int old_run;
  Term rolename;

  rd = sys->traceEvent[trace_index];
  rid = sys->traceRun[trace_index];
  /*
   * Two options: it is either involved or not
   */
  // 1. Assume that this run is not yet involved 
#ifdef OKIDEBUG
  indact ();
  printf ("Exploring further assuming (send) run %i is not involved.\n", rid);
  indac++;
#endif
  result = oki_nisynch (sys, trace_index - 1, role_to_run, label_to_index);
#ifdef OKIDEBUG
  indact ();
  printf (">%i<\n", result);
  indac--;
#endif
  if (result)
    return 1;

#ifdef OKIDEBUG
  indact ();
  printf ("Exploring when %i is involved.\n", rid);
#endif
  // 2. It is involved. Then either already used for this role, or will be now.
  rolename = sys->runs[rid].role->nameterm;
  old_run = termmapGet (role_to_run, rolename);	// what was already stored for this role as the runid
  if (old_run == -1 || old_run == rid)
    {
      int partner_index;

      // Was not involved yet in a registerd way, or was the correct rid
      partner_index = termmapGet (label_to_index, rd->label);
      // Ordered match needed for this label
      // So it already needs to be filled by a read
      if (partner_index >= 0)
	{
	  // There is already a read for it
	  if (events_match (sys, partner_index, trace_index) == MATCH_ORDER)
	    {
	      // They match in the right order
	      Termmap role_to_run_buf, label_to_index_buf;

#ifdef OKIDEBUG
	      indact ();
	      printf ("Matching messages found for label ");
	      termPrint (rd->label);
	      printf ("\n");
#endif
	      /**
	       *@todo Optimization can be done when old_run == rid, no copy of role_to_run needs to be made.
	       */
	      role_to_run_buf = termmapDuplicate (role_to_run);
	      role_to_run_buf = termmapSet (role_to_run_buf, rolename, rid);
	      label_to_index_buf = termmapDuplicate (label_to_index);
	      label_to_index_buf =
		termmapSet (label_to_index_buf, rd->label, LABEL_GOOD);
#ifdef OKIDEBUG
	      indact ();
	      printf ("In NI-Synch scan, assuming %i run is involved.\n",
		      rid);
	      indact ();
	      printf
		("Exploring further assuming this matching, which worked.\n");
	      indac++;
#endif
	      result =
		oki_nisynch (sys, trace_index - 1, role_to_run_buf,
			     label_to_index_buf);
#ifdef OKIDEBUG
	      indact ();
	      printf (">%i<\n", result);
	      indac--;
#endif
	      termmapDelete (label_to_index_buf);
	      termmapDelete (role_to_run_buf);
	      return result;
	    }
	}
    }
  return 0;
}


//! nisynch generalization
/**
 * role_to_run maps the involved roles to run identifiers.
 * label_to_index maps all labels in prec to the event indices for things already found,
 * or to LABEL_TODO for things not found yet but in prec, and LABEL_GOOD for well linked messages (and that have thus defined a runid for the corresponding role).
 * All values not in prec map to -1.
 *@returns 1 iff the claim is allright, 0 iff it is violated.
 */
int
oki_nisynch (const System sys, const int trace_index,
	     const Termmap role_to_run, const Termmap label_to_index)
{
  int type;

  // Check for completed trace
  if (trace_index < 0)
    return oki_nisynch_full (sys, label_to_index);

#ifdef OKIDEBUG
  indact ();
  printf ("Checking event %i", trace_index);
  printf (" = #%i : ", sys->traceRun[trace_index]);
  roledefPrint (sys->traceEvent[trace_index]);
  printf ("\n");
#endif

  type = sys->traceEvent[trace_index]->type;

  if (type == CLAIM || sys->traceEvent[trace_index]->internal)
    return oki_nisynch_other (sys, trace_index, role_to_run, label_to_index);
  if (type == READ)
    return oki_nisynch_read (sys, trace_index, role_to_run, label_to_index);
  if (type == SEND)
    return oki_nisynch_send (sys, trace_index, role_to_run, label_to_index);
  /*
   * Exception: no claim, no send, no read, what is it?
   */
  error ("Unrecognized event type in claim scanner at %i.", trace_index);
}

/*
 * Real checks
 */

//! Check validity of ni-synch claim at event i.
/**
 *@returns 1 iff claim is true.
 */
int
check_claim_nisynch (const System sys, const int i)
{
  Roledef rd;
  int result;
  int rid;
  Termmap f, g;
  Term label;
  Claimlist cl;
  Termlist tl;

  rid = sys->traceRun[i];
  rd = sys->traceEvent[i];
  cl = rd->claiminfo;
  cl->count = statesIncrease (cl->count);
  f = termmapSet (NULL, sys->runs[rid].role->nameterm, rid);

  // map all labels in prec to LABEL_TODO
  g = NULL;
  label = rd->label;

  tl = cl->prec;
  while (tl != NULL)
    {
      g = termmapSet (g, tl->term, LABEL_TODO);
      tl = tl->next;
    }
  /*
   * Check claim
   */
  result = oki_nisynch (sys, i, f, g);
  if (!result)
    {
#ifdef DEBUG
      globalError++;
      warning ("Claim has failed!");
      eprintf ("To be exact, claim label ");
      termPrint (cl->label);
      eprintf (" with prec set ");
      termlistPrint (cl->prec);
      eprintf ("\n");
      eprintf ("i: %i\nf: ", i);
      termmapPrint (f);
      eprintf ("\ng: ");
      termmapPrint (g);
      eprintf ("\n");
      globalError--;
#endif

    }
  termmapDelete (f);
  termmapDelete (g);
  return result;
}

//! Check validity of ni-agree claim at event i.
/**
 *@returns 1 iff claim is true.
 *@todo This is now just a copy of ni-synch, should be fixed asap.
 */
int
check_claim_niagree (const System sys, const int i)
{
  Roledef rd;
  int result;
  int rid;
  Termmap f, g;
  Term label;
  Claimlist cl;
  Termlist tl;

  rid = sys->traceRun[i];
  rd = sys->traceEvent[i];
  cl = rd->claiminfo;
  cl->count = statesIncrease (cl->count);
  f = termmapSet (NULL, sys->runs[rid].role->nameterm, rid);

  // map all labels in prec to LABEL_TODO
  g = NULL;
  label = rd->label;

  tl = cl->prec;
  while (tl != NULL)
    {
      g = termmapSet (g, tl->term, LABEL_TODO);
      tl = tl->next;
    }
  /*
   * Check claim
   */
  result = oki_nisynch (sys, i, f, g);
  if (!result)
    {
#ifdef DEBUG
      warning ("Claim has failed!");
      printf ("To be exact, claim label ");
      termPrint (cl->label);
      printf (" with prec set ");
      termlistPrint (cl->prec);
      printf ("\n");
      printf ("i: %i\nf: ", i);
      termmapPrint (f);
      printf ("\ng: ");
      termmapPrint (g);
      printf ("\n");
#endif

    }
  termmapDelete (f);
  termmapDelete (g);
  return result;
}



//! Check generic agree claim for a given set of runs, arachne style
int
arachne_runs_agree (const System sys, const Claimlist cl, const Termmap runs)
{
  Termlist labels;
  int flag;

#ifdef DEBUG
  if (DEBUGL (5))
    {
      eprintf ("Checking runs agreement for Arachne.\n");
      termmapPrint (runs);
      eprintf ("\n");
    }
#endif

  flag = 1;
  labels = cl->prec;
  while (flag && labels != NULL)
    {
      // For each label, check whether it matches. Maybe a bit too strict (what about variables?)
      // Locate roledefs for read & send, and check whether they are before step
      Roledef rd_send, rd_read;
      Labelinfo linfo;

      Roledef get_label_event (const Term role, const Term label)
      {
	Roledef rd, rd_res;
	int i;
	int run;

	run = termmapGet (runs, role);
	if (run != -1)
	  {
#ifdef DEBUG
	    if (run < 0 || run >= sys->maxruns)
	      {
		globalError++;
		eprintf ("Run mapping %i out of bounds for role ", run);
		termPrint (role);
		eprintf (" and label ");
		termPrint (label);
		eprintf ("\n");
		eprintf ("This label has sendrole ");
		termPrint (linfo->sendrole);
		eprintf (" and readrole ");
		termPrint (linfo->readrole);
		eprintf ("\n");
		globalError--;
		error ("Run mapping is out of bounds.");
	      }
#endif
	    rd = sys->runs[run].start;
	    rd_res = NULL;
	    i = 0;
	    while (i < sys->runs[run].step && rd != NULL)
	      {
		if (isTermEqual (rd->label, label))
		  {
		    rd_res = rd;
		    rd = NULL;
		  }
		else
		  {
		    rd = rd->next;
		  }
		i++;
	      }
	    return rd_res;
	  }
	else
	  {
	    return NULL;
	  }
      }

      // Main
      linfo = label_find (sys->labellist, labels->term);
      rd_send = get_label_event (linfo->sendrole, labels->term);
      rd_read = get_label_event (linfo->readrole, labels->term);

      if (rd_send == NULL || rd_read == NULL)
	{
	  // False!
	  flag = 0;
	}
      else
	{
	  // Compare
	  if (events_match_rd (rd_send, rd_read) != MATCH_CONTENT)
	    {
	      // False!
	      flag = 0;
	    }
	}

      labels = labels->next;
    }
  return flag;
}

//! Check arachne authentications claim
/**
 * Per default, occurs in run 0, but for generality we have left the run parameter in.
 *@returns 1 if the claim is true, 0 if it is not.
 */
int
arachne_claim_authentications (const System sys, const int claim_run,
			       const int claim_index, const int require_order)
{
  Claimlist cl;
  Roledef rd;
  Termmap runs_involved;
  int flag;

  int fill_roles (Termlist roles_tofill)
  {
    if (roles_tofill == NULL)
      {
	// All roles have been chosen
	if (arachne_runs_agree (sys, cl, runs_involved))
	  {
	    // niagree holds
	    if (!require_order)
	      {
		return 1;
	      }
	    else
	      {
		// Stronger claim: nisynch. Test for ordering as well.
		return labels_ordered (runs_involved, cl->prec);
	      }
	  }
	else
	  {
	    // niagree does not hold
	    return 0;
	  }
      }
    else
      {
	// Choose a run for this role, if possible
	// Note that any will do
	int run, flag;

	run = 0;
	flag = 0;
	while (run < sys->maxruns)
	  {
	    // Has to be from the right protocol
	    if (sys->runs[run].protocol == cl->protocol)
	      {
		// Has to be the right name
		if (isTermEqual
		    (sys->runs[run].role->nameterm, roles_tofill->term))
		  {
		    // Choose, iterate
		    runs_involved =
		      termmapSet (runs_involved, roles_tofill->term, run);
		    flag = flag || fill_roles (roles_tofill->next);
		  }
	      }
	    run++;
	  }
	return flag;
      }
  }

#ifdef DEBUG
  if (DEBUGL (5))
    {
      eprintf ("Testing for Niagree claim with any sort of runs.\n");
    }
#endif

  rd = roledef_shift (sys->runs[claim_run].start, claim_index);
#ifdef DEBUG
  if (rd == NULL)
    error ("Retrieving claim info for NULL node??");
#endif
  cl = rd->claiminfo;

  runs_involved = termmapSet (NULL, cl->roles->term, claim_run);
  flag = fill_roles (cl->roles->next);

  termmapDelete (runs_involved);
  return flag;
}

//! Test niagree
int
arachne_claim_niagree (const System sys, const int claim_run,
		       const int claim_index)
{
  return arachne_claim_authentications (sys, claim_run, claim_index, 0);
}

//! Test nisynch
int
arachne_claim_nisynch (const System sys, const int claim_run,
		       const int claim_index)
{
  return arachne_claim_authentications (sys, claim_run, claim_index, 1);
}

//! Prune determination for specific properties
/**
 * Sometimes, a property holds in part of the tree. Thus, we don't need to explore that part further if we want to find an attack.
 *
 *@returns true iff this state is invalid for some reason
 */
int
prune_claim_specifics (const System sys)
{
  if (sys->current_claim->type == CLAIM_Niagree)
    {
      if (arachne_claim_niagree (sys, 0, sys->current_claim->ev))
	{
	  sys->current_claim->count =
	    statesIncrease (sys->current_claim->count);
	  if (switches.output == PROOF)
	    {
	      indentPrint ();
	      eprintf
		("Pruned: niagree holds in this part of the proof tree.\n");
	    }
	  return 1;
	}
    }
  if (sys->current_claim->type == CLAIM_Nisynch)
    {
      if (arachne_claim_nisynch (sys, 0, sys->current_claim->ev))
	{
	  sys->current_claim->count =
	    statesIncrease (sys->current_claim->count);
	  if (switches.output == PROOF)
	    {
	      indentPrint ();
	      eprintf
		("Pruned: nisynch holds in this part of the proof tree.\n");
	    }
	  return 1;
	}
    }
  return 0;
}

//! Setup system for specific claim test
void
add_claim_specifics (const System sys, const Claimlist cl, const Roledef rd)
{
  if (cl->type == CLAIM_Secret)
    {
      /**
       * Secrecy claim
       */
      if (switches.output == PROOF)
	{
	  indentPrint ();
	  eprintf ("* To verify the secrecy claim, we add the term ");
	  termPrint (rd->message);
	  eprintf (" as a goal.\n");
	  indentPrint ();
	  eprintf
	    ("* If all goals can be bound, this constitutes an attack.\n");
	}

      /**
       * We say that a state exists for secrecy, but we don't really test wheter the claim can
       * be reached (without reaching the attack).
       */
      cl->count = statesIncrease (cl->count);
      goal_add (rd->message, 0, cl->ev, 0);	// Assumption that all claims are in run 0
    }

  if (cl->type == CLAIM_Reachable)
    {
      if (switches.check)
	{
	  // For reachability claims in check mode, we restrict the number of runs to the number of roles of this protocol
	  Protocol protocol;
	  int rolecount;

	  protocol = (Protocol) cl->protocol;
	  rolecount = termlistLength (protocol->rolenames);
	  switches.runs = rolecount;
	}
    }
}

//! Count a false claim
/**
 * Counts global attacks as well as claim instances.
 */
void
count_false_claim (const System sys)
{
  sys->attackid++;
  sys->current_claim->failed = statesIncrease (sys->current_claim->failed);
}


//! Check properties
int
property_check (const System sys)
{
  int flag;
  int cost;

  flag = 1;

  /* Do we need any? */
  if (enoughAttacks (sys))
    return flag;

  /**
   * By the way the claim is handled, this automatically means a flaw.
   */
  count_false_claim (sys);
  if (switches.output == ATTACK)
    {
      arachneOutputAttack ();
    }
  // Store attack cost if cheaper
  cost = attackCost (sys);
  if (cost < attack_leastcost)
    {
      // Cheapest attack
      attack_leastcost = cost;
      if (switches.output == PROOF)
	{
	  indentPrint ();
	  eprintf ("New cheaper attack found with cost %i.\n", cost);
	}
    }

  return flag;
}