/* * Scyther : An automatic verifier for security protocols. * Copyright (C) 2007 Cas Cremers * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /** * *@file claim.c * * Claim handling for the Arachne engine. * */ #include #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 "color.h" #include "cost.h" #include "timer.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 // Forward declaration int oki_nisynch (const System sys, const int trace_index, const Termmap role_to_run, const Termmap label_to_index); /* * 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) { eprintf ("| "); 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 (); eprintf ("Incorrectly linked label at the end,"); eprintf ("label: "); termPrint (label_to_index_scan->term); eprintf ("\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 (); eprintf ("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 (); eprintf (">%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 (); eprintf ("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 (); eprintf (">%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 (); eprintf ("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 (); eprintf ("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 (); eprintf (">%i<\n", result); indac--; #endif if (result) return 1; #ifdef OKIDEBUG indact (); eprintf ("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 (); eprintf ("Matching messages found for label "); termPrint (rd->label); eprintf ("\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 (); eprintf ("In NI-Synch scan, assuming %i run is involved.\n", rid); indact (); eprintf ("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 (); eprintf (">%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 (); eprintf ("Checking event %i", trace_index); eprintf (" = #%i : ", sys->traceRun[trace_index]); roledefPrint (sys->traceEvent[trace_index]); eprintf ("\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); return 0; } /* * 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!"); 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"); #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); if (!linfo->ignore) { 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); } //! Are all agents trusted of the claim run (as required by the property?) int pruneClaimRunTrusted (const System sys) { if (sys->trustedRoles == NULL) { // all agents need to be trusted if (!isRunTrusted (sys, 0)) { return true; } } else { // a subset is trusted if (!isAgentlistTrusted (sys, sys->trustedRoles)) { return true; } } return false; } //! 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) { // generic status of (all) roles trusted or not if (pruneClaimRunTrusted (sys)) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because all agents of the claim run must be trusted.\n"); } return true; } // specific claims 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 and iterate int add_claim_specifics (const System sys, const Claimlist cl, const Roledef rd, int (*callback) (void)) { /* * different cases */ // per default, all agents are trusted sys->trustedRoles = NULL; if (cl->type == CLAIM_Secret) { int newgoals; int flag; /** * 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); newgoals = goal_add (rd->message, 0, cl->ev, 0); // Assumption that all claims are in run 0 flag = callback (); goal_remove_last (newgoals); return flag; } if (cl->type == CLAIM_Reachable) { int flag; 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; } if (rd->message != NULL) { sys->trustedRoles = tuple_to_termlist (rd->message); #ifdef DEBUG if (DEBUGL (2)) { eprintf ("Trusted roles : "); termlistPrint (sys->trustedRoles); eprintf ("\n"); } #endif } flag = callback (); if (rd->message != NULL) { termlistDelete (sys->trustedRoles); sys->trustedRoles = NULL; } return flag; } return callback (); } //! 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; /** * 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; } /* claim status reporting */ //! Print something bad void printBad (char *s) { eprintf ("%s%s%s", COLOR_Red, s, COLOR_Reset); } //! Print something good void printGood (char *s) { eprintf ("%s%s%s", COLOR_Green, s, COLOR_Reset); } //! Print state (existState, isAttack) /** * Fail == ( existState xor isAttack ) */ void printOkFail (int existState, int isAttack) { if (existState != isAttack) { printGood ("Ok"); } else { printBad ("Fail"); } } //! Report claim status int claimStatusReport (const System sys, Claimlist cl) { if (isTermEqual (cl->type, CLAIM_Empty)) { return false; } else { Protocol protocol; Term pname; Term rname; Termlist labellist; int isAttack; // stores whether this claim failure constitutes an attack or not if (switches.output != SUMMARY) { globalError++; } if (isTermEqual (cl->type, CLAIM_Reachable)) { // An attack on reachable is not really an attack, we're just generating the state space isAttack = false; } else { isAttack = true; } eprintf ("claim\t"); protocol = (Protocol) cl->protocol; pname = protocol->nameterm; rname = cl->rolename; labellist = tuple_to_termlist (cl->label); /* maybe the label contains duplicate info: if so, we remove it here */ { Termlist tl; tl = labellist; while (tl != NULL) { if (isTermEqual (tl->term, pname) || isTermEqual (tl->term, rname)) { tl = termlistDelTerm (tl); labellist = tl; } else { tl = tl->next; } } } termPrint (pname); eprintf (","); termPrint (rname); eprintf ("\t"); /* second print event_label */ termPrint (cl->type); eprintf ("_"); if (labellist != NULL) { Termlist tl; tl = labellist; while (tl != NULL) { termPrint (tl->term); tl = tl->next; if (tl != NULL) { eprintf (","); } } /* clean up */ termlistDelete (labellist); labellist = NULL; } else { eprintf ("?"); } /* add parameter */ eprintf ("\t"); if (cl->parameter != NULL) { termPrint (cl->parameter); } else { eprintf ("-"); } /* now report the status */ eprintf ("\t"); if (cl->count > 0 && cl->failed > 0) { /* there is a state */ printOkFail (true, isAttack); eprintf ("\t"); /* are these all attacks? */ eprintf ("["); if (cl->complete) { eprintf ("exactly"); } else { eprintf ("at least"); } eprintf (" %i ", cl->failed); if (isAttack) { eprintf ("attack"); } else { eprintf ("variant"); } if (cl->failed != 1) { eprintf ("s"); } eprintf ("]"); } else { /* no state */ printOkFail (false, isAttack); eprintf ("\t"); /* subcases */ if (cl->count == 0) { /* not encountered */ eprintf ("[does not occur]"); } else { /* does occur */ if (cl->complete) { /* complete proof */ eprintf ("[proof of correctness]"); } else { /* only due to bounds */ eprintf ("[no attack within bounds]"); } } if (cl->timebound) eprintf ("\ttime=%i", get_time_limit ()); } /* states (if asked) */ if (switches.countStates) { eprintf ("\tstates="); statesFormat (cl->states); } /* any warnings */ if (cl->warnings) { eprintf ("\t[read the warnings for more information]"); } /* new line */ eprintf ("\n"); if (switches.output != SUMMARY) { globalError--; } return true; } }