/** * *@file arachne.c * * Introduces a method for proofs akin to the Athena modelchecker * http://www.ece.cmu.edu/~dawnsong/athena/ * */ #include #include #include #ifdef DEBUG #include #endif #include "term.h" #include "termlist.h" #include "role.h" #include "system.h" #include "knowledge.h" #include "compiler.h" #include "states.h" #include "mgu.h" #include "arachne.h" #include "memory.h" #include "error.h" #include "claim.h" #include "debug.h" #include "binding.h" #include "warshall.h" #include "timer.h" #include "type.h" #include "switches.h" #include "specialterm.h" extern int *graph; extern int nodes; extern int graph_uordblks; static System sys; static int attack_length; Protocol INTRUDER; // Pointers, to be set by the Init Role I_M; // Same here. Role I_RRS; Role I_RRSD; static int indentDepth; static int prevIndentDepth; static int indentDepthChanges; static int proofDepth; static int max_encryption_level; static int num_regular_runs; static int num_intruder_runs; struct goalstruct { int run; int index; Roledef rd; }; typedef struct goalstruct Goal; /** * Forward declarations */ int iterate (); void printSemiState (); /** * Program code */ //! Init Arachne engine void arachneInit (const System mysys) { Roledef rd; Termlist tl, know0; void add_event (int event, Term message) { rd = roledefAdd (rd, event, NULL, NULL, NULL, message, NULL); } Role add_role (const char *rolenamestring) { Role r; Term rolename; rolename = makeGlobalConstant (rolenamestring); r = roleCreate (rolename); r->roledef = rd; rd = NULL; r->next = INTRUDER->roles; INTRUDER->roles = r; // compute_role_variables (sys, INTRUDER, r); return r; } sys = mysys; // make sys available for this module as a global /** * Very important: turn role terms that are local to a run, into variables. */ term_rolelocals_are_variables (); /* * Add intruder protocol roles */ INTRUDER = protocolCreate (makeGlobalConstant (" INTRUDER ")); // Initially empty roledef rd = NULL; add_event (SEND, NULL); I_M = add_role ("I_M: Atomic message"); add_event (READ, NULL); add_event (READ, NULL); add_event (SEND, NULL); I_RRS = add_role ("I_E: Encrypt"); add_event (READ, NULL); add_event (READ, NULL); add_event (SEND, NULL); I_RRSD = add_role ("I_D: Decrypt"); num_regular_runs = 0; num_intruder_runs = 0; max_encryption_level = 0; indentDepth = 0; prevIndentDepth = 0; indentDepthChanges = 0; return; } //! Close Arachne engine void arachneDone () { return; } //------------------------------------------------------------------------ // Detail //------------------------------------------------------------------------ /* * runs[rid].step is now the number of 'valid' events within the run, but we * call it 'length' here. */ #define INVALID -1 #define isGoal(rd) (rd->type == READ && !rd->internal) #define isBound(rd) (rd->bound) #define length step //! Indent prefix print void indentPrefixPrint (const int annotate, const int jumps) { if (switches.output == ATTACK && globalError == 0) { // Arachne, attack, not an error // We assume that means DOT output eprintf ("// %i\t", annotate); } else { // If it is not to stdout, or it is not an attack... int i; eprintf ("%i\t", annotate); for (i = 0; i < jumps; i++) { if (i % 3 == 0) eprintf ("|"); else eprintf (" "); eprintf (" "); } } } //! Indent print /** * More subtle than before. Indentlevel changes now cause a counter to be increased, which is printed. Nice to find stuff in attacks. */ void indentPrint () { if (indentDepth != prevIndentDepth) { indentDepthChanges++; while (indentDepth != prevIndentDepth) { if (prevIndentDepth < indentDepth) { indentPrefixPrint (indentDepthChanges, prevIndentDepth); eprintf ("{\n"); prevIndentDepth++; } else { prevIndentDepth--; indentPrefixPrint (indentDepthChanges, prevIndentDepth); eprintf ("}\n"); } } } indentPrefixPrint (indentDepthChanges, indentDepth); } //! Print indented binding void binding_indent_print (const Binding b, const int flag) { indentPrint (); if (flag) eprintf ("!! "); binding_print (b); eprintf ("\n"); } //! Determine whether a term is a functor int isTermFunctionName (Term t) { t = deVar (t); if (t != NULL && isTermLeaf (t) && t->stype != NULL && inTermlist (t->stype, TERM_Function)) return 1; return 0; } //! Determine whether a term is a function application. Returns the function term. Term getTermFunction (Term t) { t = deVar (t); if (t != NULL) { if (realTermEncrypt (t) && isTermFunctionName (TermKey (t))) { return TermKey (t); } } return NULL; } //! Keylevel tester: can this term ever be sent at this keylevel? int isKeylevelRight (Term t, const int kl) { t = deVar (t); if (realTermLeaf (t)) { // Leaf if (isTermVariable (t)) { // Variables are okay return 1; } else { // Constant, does it have a keylevel? int mykl; mykl = TermSymb (t)->keylevel; if (mykl < INT_MAX) { // Sensible keylevel, so it must be possible return (mykl <= kl); } else { // Never sent? // So we can not expect it to come from that return 0; } } } else { // Node if (realTermTuple (t)) { // Tuple return isKeylevelRight (TermOp1 (t), kl) && isKeylevelRight (TermOp2 (t), kl); } else { // Crypt return isKeylevelRight (TermOp1 (t), kl) && isKeylevelRight (TermOp2 (t), kl + 1); } } } //! Keylevel tester: can this term ever be sent at this keylevel? /** * Depends on the keylevel lemma (TODO) and the keylevel constructors in symbol.c * The idea is that certain terms will never be sent. */ int isPossiblySent (Term t) { return isKeylevelRight (t, 0); } //! Wrapper for roleInstance /** *@return Returns the run number */ int semiRunCreate (const Protocol p, const Role r) { int run; if (p == INTRUDER) num_intruder_runs++; else num_regular_runs++; roleInstance (sys, p, r, NULL, NULL); run = sys->maxruns - 1; sys->runs[run].length = 0; return run; } //! Wrapper for roleDestroy void semiRunDestroy () { if (sys->maxruns > 0) { Protocol p; p = sys->runs[sys->maxruns - 1].protocol; roleInstanceDestroy (sys); if (p == INTRUDER) num_intruder_runs--; else num_regular_runs--; } } //! Fix the keylevels of any agents /** * We simply extract the agent names from m0 (ugly hack) */ void fixAgentKeylevels (void) { Termlist tl, m0tl; m0tl = knowledgeSet (sys->know); tl = m0tl; while (tl != NULL) { Term t; t = deVar (tl->term); if (realTermLeaf (t)) { { // a real agent type thing if (TermSymb (t)->keylevel == INT_MAX) { // Fix the keylevel TermSymb (t)->keylevel = 0; } } } tl = tl->next; } termlistDelete (m0tl); } //! After a role instance, or an extension of a run, we might need to add some goals /** * From old to new. Sets the new length to new. *@returns The number of goals added (for destructions) */ int add_read_goals (const int run, const int old, const int new) { int count; int i; Roledef rd; sys->runs[run].length = new; i = old; rd = roledef_shift (sys->runs[run].start, i); count = 0; while (i < new && rd != NULL) { if (rd->type == READ) { if (switches.output == PROOF) { if (count == 0) { indentPrint (); eprintf ("Thus, we must also produce "); } else { eprintf (", "); } termPrint (rd->message); } count = count + goal_add (rd->message, run, i, 0); } rd = rd->next; i++; } if ((count > 0) && switches.output == PROOF) { eprintf ("\n"); } return count; } //! Determine the run that follows from a substitution. /** * After an Arachne unification, stuff might go wrong w.r.t. nonce instantiation. * This function determines the run that is implied by a substitution list. * @returns >= 0: a run, -1 for invalid, -2 for any run. */ int determine_unification_run (Termlist tl) { int run; run = -2; while (tl != NULL) { //! Again, hardcoded reference to compiler.c. Level -3 means a local constant for a role. if (tl->term->type != VARIABLE && TermRunid (tl->term) == -3) { Term t; t = tl->term->subst; // It is required that it is actually a leaf, because we construct it. if (!realTermLeaf (t)) { return -1; } else { if (run == -2) { // Any run run = TermRunid (t); } else { // Specific run: compare if (run != TermRunid (t)) { return -1; } } } } tl = tl->next; } return run; } //! Determine trace length int get_semitrace_length () { int run; int length; run = 0; length = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { // Non-intruder run: count length // Subtract 'firstReal' to ignore chooses. length = length + sys->runs[run].length - sys->runs[run].firstReal; } run++; } return length; } //------------------------------------------------------------------------ // Proof reporting //------------------------------------------------------------------------ //! Protocol/role name of a run void role_name_print (const int run) { eprintf ("protocol "); termPrint (sys->runs[run].protocol->nameterm); eprintf (", role "); termPrint (sys->runs[run].role->nameterm); } //! Adding a run/extending a run void proof_suppose_run (const int run, const int oldlength, const int newlength) { if (switches.output == PROOF) { int reallength; indentPrint (); eprintf ("Suppose "); if (oldlength == 0) eprintf ("there is a "); else eprintf ("we extend "); reallength = roledef_length (sys->runs[run].start); if (reallength > newlength) eprintf ("semi-"); eprintf ("run #%i of ", run); role_name_print (run); if (reallength > newlength) { if (oldlength == 0) eprintf (" of"); else eprintf (" to"); eprintf (" length %i", newlength); } eprintf ("\n"); } } //! Select a goal void proof_select_goal (Binding b) { if (switches.output == PROOF) { Roledef rd; rd = roledef_shift (sys->runs[b->run_to].start, b->ev_to); indentPrint (); eprintf ("Selected goal: Where does term "); termPrint (b->term); eprintf (" occur first as an interm?\n"); indentPrint (); eprintf ("* It is required for "); roledefPrint (rd); eprintf (" at index %i in run %i\n", b->ev_to, b->run_to); } } //! Cannot bind because of cycle void proof_cannot_bind (const Binding b, const int run, const int index) { if (switches.output == PROOF) { indentPrint (); eprintf ("Cannot bind this to run %i, index %i because that introduces a cycle.\n", run, index); } } //! Test a binding void proof_suppose_binding (Binding b) { if (switches.output == PROOF) { Roledef rd; indentPrint (); rd = roledef_shift (sys->runs[b->run_from].start, b->ev_from); eprintf ("Suppose it originates in run %i, at index %i\n", b->run_from, b->ev_from); indentPrint (); eprintf ("* I.e. event "); roledefPrint (rd); eprintf ("\n"); indentPrint (); eprintf ("* from "); role_name_print (b->run_from); eprintf ("\n"); } } //------------------------------------------------------------------------ // Sub //------------------------------------------------------------------------ //! Iterate over all events in the roles (including the intruder ones) /** * Function is called with (protocol pointer, role pointer, roledef pointer, index) * and returns an integer. If it is false, iteration aborts. */ int iterate_role_events (int (*func) ()) { Protocol p; p = sys->protocols; while (p != NULL) { Role r; r = p->roles; while (r != NULL) { Roledef rd; int index; rd = r->roledef; index = 0; while (rd != NULL) { if (!func (p, r, rd, index)) return 0; index++; rd = rd->next; } r = r->next; } p = p->next; } return 1; } //! Iterate over all send types in the roles (including the intruder ones) /** * Function is called with (protocol pointer, role pointer, roledef pointer, index) * and returns an integer. If it is false, iteration aborts. */ int iterate_role_sends (int (*func) ()) { int send_wrapper (Protocol p, Role r, Roledef rd, int i) { if (rd->type == SEND) { return func (p, r, rd, i); } else { return 1; } } return iterate_role_events (send_wrapper); } //! Create decryption role instance /** * Note that this does not add any bindings for the reads. * *@param term The term to be decrypted (implies decryption key) * *@returns The run id of the decryptor instance */ int create_decryptor (const Term term, const Term key) { if (term != NULL && isTermEncrypt (term)) { Roledef rd; Term tempkey; int run; run = semiRunCreate (INTRUDER, I_RRSD); rd = sys->runs[run].start; rd->message = termDuplicateUV (term); rd->next->message = termDuplicateUV (key); rd->next->next->message = termDuplicateUV (TermOp (term)); sys->runs[run].step = 3; proof_suppose_run (run, 0, 3); return run; } else { globalError++; printf ("Term for which a decryptor instance is requested: "); termPrint (term); printf ("\n"); error ("Trying to build a decryptor instance for a non-encrypted term."); } } //! Get the priority level of a key that is needed for a term (typical pk/sk distinction) int getPriorityOfNeededKey (const System sys, const Term keyneeded) { int prioritylevel; /* Normally, a key gets higher priority, but unfortunately this is not propagated at the moment. Maybe later. */ prioritylevel = 1; if (realTermEncrypt (keyneeded)) { /* the key is a construction itself */ if (inKnowledge (sys->know, TermKey (keyneeded))) { /* the key is constructed by a public thing */ /* typically, this is a public key, so we postpone it */ prioritylevel = -1; } } return prioritylevel; } //! Try to bind a specific existing run to a goal. /** * The key goals are bound to the goal. * *@todo This is currently NOT correct. The point is that the key chain * cannot uniquely define a path through a term in general, and * a rewrite of termMguSubterm is needed. It should not yield the * needed keys, but simply the path throught the term. This would enable * reconstruction of the keys anyway. TODO * *@param subterm determines whether it is a subterm unification or not. */ int bind_existing_to_goal (const Binding b, const int run, const int index) { Roledef rd; int flag; int old_length; int newgoals; int found; int subterm_iterate (Termlist substlist, Termlist cryptlist) { int flag; found++; flag = 1; /** * Now create the new bindings */ int newgoals; int newruns; int stillvalid; Binding smalltermbinding; stillvalid = true; // New stuff is valid (no cycles) newgoals = 0; // No new goals introduced (yet) newruns = 0; // New runs introduced smalltermbinding = b; // Start off with destination binding indentDepth++; #ifdef DEBUG if (DEBUGL (4)) { printf ("Trying to bind the small term "); termPrint (b->term); printf (" as coming from the big send "); termPrint (rd->message); printf (" , binding "); termPrint (b->term); printf ("\nCrypted list needed: "); termlistPrint (cryptlist); printf ("\n"); } #endif if (cryptlist != NULL && switches.output == PROOF) { indentPrint (); eprintf ("This introduces the obligation to decrypt the following encrypted subterms: "); termlistPrint (cryptlist); eprintf ("\n"); } /* The order of the cryptlist is inner -> outer */ while (stillvalid && cryptlist != NULL && smalltermbinding != NULL) { /* * Invariants: * * smalltermbinding binding to be satisfied next (and for which a decryptor is needed) */ Term keyneeded; int prioritylevel; int smallrun; int count; Roledef rddecrypt; Binding bnew; int res; /* * 1. Add decryptor */ keyneeded = inverseKey (sys->know->inverses, TermKey (cryptlist->term)); prioritylevel = getPriorityOfNeededKey (sys, keyneeded); smallrun = create_decryptor (cryptlist->term, keyneeded); rddecrypt = sys->runs[smallrun].start; termDelete (keyneeded); newruns++; /* * 2. Add goal bindings */ count = goal_add (rddecrypt->message, smallrun, 0, 0); newgoals = newgoals + count; if (count >= 0) { if (count > 1) { error ("Added more than one goal for decryptor goal 1, weird."); } else { // This is the unique new goal then bnew = (Binding) sys->bindings->data; } } else { // No new binding? Weird, but fair enough bnew = NULL; } newgoals = newgoals + goal_add (rddecrypt->next->message, smallrun, 1, prioritylevel); /* * 3. Bind open goal to decryptor */ res = goal_bind (smalltermbinding, smallrun, 2); // returns 0 iff invalid if (res != 0) { // Allright, good binding, proceed with next smalltermbinding = bnew; } else { stillvalid = false; } /* progression */ cryptlist = cryptlist->next; } /* * Decryptors for any nested keys have been added. Now we can fill the * final binding. */ if (stillvalid) { if (goal_bind (smalltermbinding, run, index)) { proof_suppose_binding (b); #ifdef DEBUG if (DEBUGL (4)) { indentPrint (); eprintf ("Added %i new goals, iterating.\n", newgoals); } #endif /* Iterate process */ indentDepth++; flag = flag && iterate (); indentDepth--; } else { proof_cannot_bind (b, run, index); } } goal_remove_last (newgoals); while (newruns > 0) { semiRunDestroy (); newruns--; } goal_unbind (b); indentDepth--; return flag; } //---------------------------- // Roledef entry rd = roledef_shift (sys->runs[run].start, index); // Fix length old_length = sys->runs[run].length; if ((index + 1) > old_length) newgoals = add_read_goals (run, old_length, index + 1); else newgoals = 0; // Bind to existing run found = 0; flag = termMguSubTerm (b->term, rd->message, subterm_iterate, sys->know->inverses, NULL); // Did it work? if (found == 0 && switches.output == PROOF) { indentPrint (); eprintf ("Cannot bind "); termPrint (b->term); eprintf (" to run %i, index %i because it does not subterm-unify.\n", run, index); } // Reset length goal_remove_last (newgoals); sys->runs[run].length = old_length; return flag; } //! Bind a goal to an existing regular run, if possible int bind_existing_run (const Binding b, const Protocol p, const Role r, const int index) { int run, flag; int found; flag = 1; found = 0; for (run = 0; run < sys->maxruns; run++) { if (sys->runs[run].protocol == p && sys->runs[run].role == r) { found++; if (switches.output == PROOF) { if (found == 1) { indentPrint (); eprintf ("Can we bind it to an existing regular run of "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf ("?\n"); } indentPrint (); eprintf ("%i. Can we bind it to run %i?\n", found, run); } indentDepth++; flag = flag && bind_existing_to_goal (b, run, index); indentDepth--; } } if (switches.output == PROOF && found == 0) { indentPrint (); eprintf ("There is no existing run for "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf ("\n"); } return flag; } //! Bind a goal to a new run int bind_new_run (const Binding b, const Protocol p, const Role r, const int index) { int run; int flag; int newgoals; run = semiRunCreate (p, r); proof_suppose_run (run, 0, index + 1); { newgoals = add_read_goals (run, 0, index + 1); indentDepth++; flag = bind_existing_to_goal (b, run, index); indentDepth--; goal_remove_last (newgoals); } semiRunDestroy (); return flag; } //! Convert a list of ranks to a list of lines (0..) /** * The interesting bit is that the ranks include the intruder events. Thus, we need to filter those out of * the system. * * Returns the baseline of the highest number + 1; thus the number of lines. */ int ranks_to_lines (int *ranks, const int nodes) { int ranksdone, baseline; ranksdone = 0; // All values lower than this have been done, so it is the next value baseline = 0; // The line numbers that get assigned while (1) { int newlow; int run; int i; // Determine lowest rank for non-intruder events, that has not been done newlow = INT_MAX; run = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { int ev; ev = 0; while (ev < sys->runs[run].step) { int nrank; nrank = ranks[node_number (run, ev)]; if (nrank < newlow && nrank >= ranksdone) { newlow = nrank; } ev++; } } run++; } if (newlow == INT_MAX) { // All are done return baseline; } // Convert the nodes between ranksdone and newlow to baseline i = 0; while (i < nodes) { if (ranks[i] <= newlow && ranks[i] >= ranksdone) { ranks[i] = baseline; } i++; } baseline++; ranksdone = newlow + 1; } } //! Iterate over all events that have an incoming arrow to the current one (forgetting the intruder for a moment) void iterate_incoming_arrows (void (*func) (), const int run, const int ev) { /** * Determine wheter to draw an incoming arrow to this event. * We check all other runs, to see if they are ordered. */ int run2; run2 = 0; while (run2 < sys->maxruns) { if (run2 != run && sys->runs[run2].protocol != INTRUDER) { // Is this run before the event? int ev2; int found; found = 0; ev2 = sys->runs[run2].length; while (found == 0 && ev2 > 0) { ev2--; if (graph[graph_nodes (nodes, run2, ev2, run, ev)] != 0) { found = 1; } } if (found == 1) { // It is before the event, and thus we would like to draw it. // However, if there is another path along which we can get here, forget it /** * Note that this algorithm is similar to Floyd's algorithm for all shortest paths. * The goal here is to select only the path with distance 1 (as viewed from the regular runs), * so we can simplify stuff a bit. * Nevertheless, using Floyd first would probably be faster. */ int other_route; int run3; int ev3; other_route = 0; run3 = 0; ev3 = 0; while (other_route == 0 && run3 < sys->maxruns) { if (sys->runs[run3].protocol != INTRUDER) { ev3 = 0; while (other_route == 0 && ev3 < sys->runs[run3].length) { if (graph [graph_nodes (nodes, run2, ev2, run3, ev3)] != 0 && graph[graph_nodes (nodes, run3, ev3, run, ev)] != 0) { // other route found other_route = 1; } ev3++; } } run3++; } if (other_route == 0) { func (run2, ev2); } } } run2++; } } //! Iterate over all events that have an outgoing arrow from the current one (forgetting the intruder for a moment) void iterate_outgoing_arrows (void (*func) (), const int run, const int ev) { /** * Determine wheter to draw an incoming arrow to this event. * We check all other runs, to see if they are ordered. */ int run2; run2 = 0; while (run2 < sys->maxruns) { if (run2 != run && sys->runs[run2].protocol != INTRUDER) { // Is this run after the event? int ev2; int found; found = 0; ev2 = 0; while (found == 0 && ev2 < sys->runs[run2].length) { if (graph[graph_nodes (nodes, run, ev, run2, ev2)] != 0) { found = 1; } else { ev2++; } } if (found == 1) { // It is after the event, and thus we would like to draw it. // However, if there is another path along which we can get there, forget it /** * Note that this algorithm is similar to Floyd's algorithm for all shortest paths. * The goal here is to select only the path with distance 1 (as viewed from the regular runs), * so we can simplify stuff a bit. * Nevertheless, using Floyd first would probably be faster. */ int other_route; int run3; int ev3; other_route = 0; run3 = 0; ev3 = 0; while (other_route == 0 && run3 < sys->maxruns) { if (sys->runs[run3].protocol != INTRUDER) { ev3 = 0; while (other_route == 0 && ev3 < sys->runs[run3].length) { if (graph [graph_nodes (nodes, run, ev, run3, ev3)] != 0 && graph[graph_nodes (nodes, run3, ev3, run2, ev2)] != 0) { // other route found other_route = 1; } ev3++; } } run3++; } if (other_route == 0) { func (run2, ev2); } } } run2++; } } //! Display the current semistate using LaTeX output format. /** * This is not as nice as we would like it. Furthermore, the function is too big, and needs to be split into functional parts that * will allow the generation of dot code as well. */ void latexSemiState () { static int attack_number = 0; int run; Protocol p; int *ranks; int maxrank, maxline; // Open graph attack_number++; eprintf ("\\begin{msc}{Attack on "); p = (Protocol) sys->current_claim->protocol; termPrint (p->nameterm); eprintf (", role "); termPrint (sys->current_claim->rolename); eprintf (", claim type "); termPrint (sys->current_claim->type); eprintf ("}\n%% Attack number %i\n", attack_number); eprintf ("\n"); // Needed for the bindings later on: create graph goal_graph_create (); // create graph if (warshall (graph, nodes) == 0) // determine closure { eprintf ("%% This graph was not completely closed transitively because it contains a cycle!\n"); } ranks = memAlloc (nodes * sizeof (int)); maxrank = graph_ranks (graph, ranks, nodes); // determine ranks // Convert ranks to lines maxline = ranks_to_lines (ranks, nodes); // Draw headings (boxes) run = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { eprintf ("\\declinst{r%i}{}{run %i}\n", run, run); } run++; } eprintf ("\\nextlevel\n\n"); // Draw all events (according to ranks) { int myline; myline = 0; while (myline < maxline) { int count; int run; count = 0; run = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { int ev; ev = 0; while (ev < sys->runs[run].step) { if (myline == ranks[node_number (run, ev)]) { Roledef rd; void outgoing_arrow (const int run2, const int ev2) { Roledef rd2; int delta; rd2 = roledef_shift (sys->runs[run2].start, ev2); eprintf ("\\mess{"); /* // Print the term // Maybe, if more than one outgoing, and different send/reads, we might want to change this a bit. if (rd->type == SEND) { if (rd2->type == CLAIM) { roledefPrint(rd); } if (rd2->type == READ) { eprintf("$"); if (isTermEqual(rd->message, rd2->message)) { termPrint(rd->message); } else { termPrint(rd->message); eprintf(" \\longrightarrow "); termPrint(rd2->message); } eprintf("$"); } } else { roledefPrint(rd); } */ /* roledefPrint (rd); eprintf (" $\\longrightarrow$ "); roledefPrint (rd2); */ eprintf ("}{r%i}{r%i}", run, run2); delta = ranks[node_number (run2, ev2)] - myline; if (delta != 0) { eprintf ("[%i]", delta); } eprintf ("\n"); count++; } // We have found an event on this line // We only need to consider reads and claims, but for fun we just consider everything. rd = roledef_shift (sys->runs[run].start, ev); iterate_outgoing_arrows (outgoing_arrow, run, ev); eprintf ("\\action{"); roledefPrint (rd); eprintf ("}{r%i}\n", run); } ev++; } } run++; } eprintf ("\\nextlevel\n"); myline++; } } // clean memory memFree (ranks, nodes * sizeof (int)); // ranks // close graph eprintf ("\\nextlevel\n\\end{msc}\n\n"); } //! Display the current semistate using dot output format. /** * This is not as nice as we would like it. Furthermore, the function is too big, and needs to be split into functional parts that * will allow the generation of LaTeX code as well. */ void dotSemiState () { static int attack_number = 0; int run; Protocol p; int *ranks; int maxrank; void node (const int run, const int index) { if (sys->runs[run].protocol == INTRUDER) { if (sys->runs[run].role == I_M) { eprintf ("m0"); } else { eprintf ("i%i", run); } } else { eprintf ("r%ii%i", run, index); } } // Open graph attack_number++; eprintf ("digraph semiState%i {\n", attack_number); eprintf ("\tlabel = \"[Id %i] Protocol ", sys->attackid); p = (Protocol) sys->current_claim->protocol; termPrint (p->nameterm); eprintf (", role "); termPrint (sys->current_claim->rolename); eprintf (", claim type "); termPrint (sys->current_claim->type); eprintf ("\";\n"); // Needed for the bindings later on: create graph goal_graph_create (); // create graph if (warshall (graph, nodes) == 0) // determine closure { eprintf ("// This graph was not completely closed transitively because it contains a cycle!\n"); } ranks = memAlloc (nodes * sizeof (int)); maxrank = graph_ranks (graph, ranks, nodes); // determine ranks #ifdef DEBUG // For debugging purposes, we also display an ASCII version of some stuff in the comments printSemiState (); // Even draw all dependencies for non-intruder runs // Real nice debugging :( { int run; run = 0; while (run < sys->maxruns) { int ev; ev = 0; while (ev < sys->runs[run].length) { int run2; int notfirstrun; eprintf ("// precedence: r%ii%i <- ", run, ev); run2 = 0; notfirstrun = 0; while (run2 < sys->maxruns) { int notfirstev; int ev2; notfirstev = 0; ev2 = 0; while (ev2 < sys->runs[run2].length) { if (graph[graph_nodes (nodes, run2, ev2, run, ev)] != 0) { if (notfirstev) eprintf (","); else { if (notfirstrun) eprintf (" "); eprintf ("r%i:", run2); } eprintf ("%i", ev2); notfirstrun = 1; notfirstev = 1; } ev2++; } run2++; } eprintf ("\n"); ev++; } run++; } } #endif // Draw graph // First, all simple runs run = 0; while (run < sys->maxruns) { Roledef rd; int index; index = 0; rd = sys->runs[run].start; if (sys->runs[run].protocol != INTRUDER && sys->runs[run].length > 0) { // Regular run /* DISABLED subgraphs eprintf ("\tsubgraph cluster_run%i {\n", run); eprintf ("\t\tlabel = \""); eprintf ("#%i: ", run); termPrint (sys->runs[run].protocol->nameterm); eprintf (", "); agentsOfRunPrint (sys, run); eprintf ("\";\n", run); if (run == 0) { eprintf ("\t\tcolor = red;\n"); } else { eprintf ("\t\tcolor = blue;\n"); } */ // Display the respective events while (index < sys->runs[run].length) { // Print node itself eprintf ("\t\t"); node (run, index); eprintf (" ["); if (run == 0 && index == sys->current_claim->ev) { eprintf ("style=filled,fillcolor=mistyrose,color=salmon,shape=doubleoctagon,"); } else { eprintf ("shape=box,"); } eprintf ("label=\""); roledefPrintShort (rd); eprintf ("\"]"); eprintf (";\n"); // Print binding to previous node if (index > sys->runs[run].firstReal) { // index > 0 eprintf ("\t\t"); node (run, index - 1); eprintf (" -> "); node (run, index); eprintf (" [style=\"bold\", weight=\"10.0\"]"); eprintf (";\n"); } else { // index <= firstReal if (index == sys->runs[run].firstReal) { // index == firstReal Roledef rd; int send_before_read; int done; // Determine if it is an active role or note /** *@todo note that this will probably become a standard function call for role.h */ rd = roledef_shift (sys->runs[run].start, sys->runs[run].firstReal); done = 0; send_before_read = 0; while (!done && rd != NULL) { if (rd->type == READ) { done = 1; } if (rd->type == SEND) { done = 1; send_before_read = 1; } rd = rd->next; } // Draw the first box // This used to be drawn only if done && send_before_read, now we always draw it. eprintf ("\t\ts%i [label=\"Run %i: ", run, run); termPrint (sys->runs[run].protocol->nameterm); eprintf (", "); termPrint (sys->runs[run].role->nameterm); eprintf ("\\n"); agentsOfRunPrint (sys, run); eprintf ("\", shape=diamond];\n"); eprintf ("\t\ts%i -> ", run); node (run, index); eprintf (";\n"); } } index++; rd = rd->next; } /* DISABLED subgraphs eprintf ("\t}\n"); */ } run++; } // Second, all bindings. // We now determine them ourselves between existing runs run = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { int ev; ev = 0; while (ev < sys->runs[run].length) { void incoming_arrow (int run2, int ev2) { Roledef rd, rd2; /* * We have decided to draw this binding, * from run2,ev2 to run,ev * However, me might need to decide some colouring for this node. */ eprintf ("\t"); node (run2, ev2); eprintf (" -> "); node (run, ev); eprintf (" "); // decide color rd = roledef_shift (sys->runs[run].start, ev); rd2 = roledef_shift (sys->runs[run2].start, ev2); if (rd->type == CLAIM) { // Towards a claim, so only indirect dependency eprintf ("[color=cornflowerblue]"); } else { // Not towards claim should imply towards read, // but we check it to comply with future stuff. if (rd->type == READ && rd2->type == SEND) { // We want to distinguish where it is from a 'broken' send if (isTermEqual (rd->message, rd2->message)) { if (isTermEqual (rd->from, rd2->from) && isTermEqual (rd->to, rd2->to)) { // Wow, a perfect match. Leave the arrow as-is :) eprintf ("[color=forestgreen]"); } else { // Same message, different people eprintf ("[label=\"redirect\",color=darkorange2]"); } } else { // Not even the same message, intruder construction eprintf ("[label=\"construct\",color=red]"); } } } // close up eprintf (";\n"); } iterate_incoming_arrows (incoming_arrow, run, ev); ev++; } } run++; } // Third, all ranking info { int myrank; #ifdef DEBUG { int n; eprintf ("/* ranks: %i\n", maxrank); n = 0; while (n < nodes) { eprintf ("%i ", ranks[n]); n++; } eprintf ("\n*/\n\n"); } #endif myrank = 0; while (myrank < maxrank) { int count; int run; int run1; int ev1; count = 0; run = 0; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { int ev; ev = 0; while (ev < sys->runs[run].step) { if (myrank == ranks[node_number (run, ev)]) { if (count == 0) eprintf ("\t{ rank = same; "); count++; eprintf ("r%ii%i; ", run, ev); } ev++; } } run++; } if (count > 0) eprintf ("}\t\t// rank %i\n", myrank); myrank++; } } // clean memory memFree (ranks, nodes * sizeof (int)); // ranks // close graph eprintf ("};\n\n"); } //! Print the current semistate void printSemiState () { int run; int open; List bl; int binding_state_print (void *dt) { binding_indent_print ((Binding) dt, 1); return 1; } indentPrint (); eprintf ("!! --=[ Semistate ]=--\n"); indentPrint (); eprintf ("!!\n"); indentPrint (); eprintf ("!! Trace length: %i\n", get_semitrace_length ()); open = 0; for (run = 0; run < sys->maxruns; run++) { int index; Role r; Roledef rd; Term oldagent; indentPrint (); eprintf ("!!\n"); indentPrint (); eprintf ("!! [ Run %i, ", run); termPrint (sys->runs[run].protocol->nameterm); eprintf (", "); r = sys->runs[run].role; oldagent = r->nameterm->subst; r->nameterm->subst = NULL; termPrint (r->nameterm); r->nameterm->subst = oldagent; if (oldagent != NULL) { eprintf (": "); termPrint (oldagent); } eprintf (" ]\n"); index = 0; rd = sys->runs[run].start; while (index < sys->runs[run].length) { indentPrint (); eprintf ("!! %i ", index); roledefPrint (rd); eprintf ("\n"); if (isGoal (rd) && !isBound (rd)) open++; index++; rd = rd->next; } } if (sys->bindings != NULL) { indentPrint (); eprintf ("!!\n"); list_iterate (sys->bindings, binding_state_print); } indentPrint (); eprintf ("!!\n"); indentPrint (); eprintf ("!! - open: %i -\n", open); } //! Give an indication of the amount of consequences binding a term has /** * Given a term, returns a float. 0: maximum consequences, 1: no consequences. */ float termBindConsequences (Term t) { Termlist openVariables; openVariables = termlistAddVariables (NULL, t); if (openVariables == NULL) { // No variables, no consequences return 1; } else { // For each run event in the semitrace, check whether it contains any // of the open variables. int totalCount; int affectedCount; int run; totalCount = 0; affectedCount = 0; run = 0; while (run < sys->maxruns) { Roledef rd; int step; rd = sys->runs[run].start; step = 0; while (step < sys->runs[run].length) { Termlist tl; tl = openVariables; while (tl != NULL) { if ((rd->type == READ || rd->type == SEND) && termSubTerm (rd->message, tl->term)) { // This run event contains the open variable affectedCount++; tl = NULL; } else { tl = tl->next; } } totalCount++; step++; rd = rd->next; } run++; } termlistDelete (openVariables); if (totalCount > 0) { // Valid computation return (float) (totalCount - affectedCount) / totalCount; } else { // No consequences, ensure no division by 0 return 1; } } } //! Determine whether a term is an open nonce variable /** * Does not explore subterms */ int isOpenNonceVar (Term t) { t = deVar (t); if (realTermVariable (t)) { return inTermlist (t->stype, TERM_Nonce); } else { return 0; } } //! Count unique open variables in term /** */ int count_open_variables (const Term t) { Termlist tl; int n; tl = NULL; termlistAddVariables (tl, t); n = 0; while (tl != NULL) { if (!inTermlist (tl->next, t)) { if (isOpenNonceVar (t)) { n = n + 1; } } tl = tl->next; } termlistDelete (tl); return n; } //! Athena-like factor /** * Lower is better (more nonce variables) */ float term_noncevariables_level (const Term t) { int onv; const int enough = 2; onv = count_open_variables (t); if (onv >= enough) { return 0; } else { return 1 - (onv / enough); } } //------------------------------------------------------------------------ // Larger logical componentents //------------------------------------------------------------------------ //! Selector to select the first tuple goal. /** * Basically to get rid of -m2 tuple goals. * Nice iteration, I'd suppose */ Binding select_tuple_goal () { List bl; Binding tuplegoal; bl = sys->bindings; tuplegoal = NULL; while (bl != NULL && tuplegoal == NULL) { Binding b; b = (Binding) bl->data; // Ignore done stuff if (!b->blocked && !b->done) { if (isTermTuple (b->term)) { tuplegoal = b; } } bl = bl->next; } return tuplegoal; } //! Goal selection /** * Selects the most constrained goal. * * First selection is on level; thus, keys are selected first. * * Because the list starts with the newest terms, and we use <= (as opposed to <), we * ensure that for goals with equal constraint levels, we select the oldest one. * * selection masks for --select-goal * 1: constrain level of term * 2: key or not * 4: consequences determination * 8: select also single variables (that are not role variables) * 16: single variables are better */ Binding select_goal () { List bl; Binding best; float min_constrain; int mode; // mode bits local storage mode = switches.arachneSelector; // Find the most constrained goal if (switches.output == PROOF) { indentPrint (); eprintf ("Listing open goals that might be chosen: "); } min_constrain = FLT_MAX; bl = sys->bindings; best = NULL; while (bl != NULL) { Binding b; b = (Binding) bl->data; // Only if not done and not blocked if (!b->blocked && !b->done) { int allow; Term gterm; allow = 0; gterm = deVar (b->term); if (mode & 8) { // check for singular variable if (realTermVariable (gterm)) { // singular variable only if it is not a role name variable allow = !gterm->roleVar; } else { // not a singular variable, allow allow = 1; } } else { // Normally (mode & 8 == 0) we ignore any singular variables allow = !realTermVariable (gterm); } if (allow) { float buf_constrain; int buf_weight; int smode; void adapt (const int w, const float fl) { buf_constrain = buf_constrain + w * fl; buf_weight = buf_weight + w; } void erode (const int w, const float fl) { if (smode & 1) { adapt (w, fl); } smode = smode / 2; } // buf_constrain is the addition of the factors before division by weight buf_constrain = 0; buf_weight = 0; if (switches.output == PROOF && best != NULL) eprintf (", "); // We will shift this mode variable smode = mode; // Determine buf_constrain levels // Bit 0: 1 constrain level erode (1, term_constrain_level (b->term)); // Bit 1: 2 key level (inverted) erode (1, 0.5 * (1 - b->level)); // Bit 2: 4 consequence level erode (1, termBindConsequences (b->term)); // Bit 3: 8 single variables first erode (1, 1 - isTermVariable (b->term)); // Bit 4: 16 nonce variables level (Cf. what I think is in Athena) erode (1, term_noncevariables_level (b->term)); // Define legal range if (smode > 0) error ("--goal-select mode %i is illegal", mode); // Weigh result if (buf_weight == 0 || buf_constrain <= min_constrain) { min_constrain = buf_constrain; best = b; if (switches.output == PROOF) eprintf ("*"); } if (switches.output == PROOF) { termPrint (b->term); if (mode & 2) { eprintf ("[%i]", b->level); } eprintf ("<%.2f>", buf_constrain); } } } bl = bl->next; } if (switches.output == PROOF) { if (best == NULL) eprintf ("none"); eprintf ("\n"); } return best; } //! Check if a binding duplicates an old one: if so, simply connect int bind_old_goal (const Binding b_new) { if (!b_new->done) { List bl; bl = sys->bindings; while (bl != NULL) { Binding b_old; b_old = (Binding) bl->data; if (b_old->done && isTermEqual (b_new->term, b_old->term)) { // Old is done and has the same term! // So we copy this binding, and fix it. b_new->run_from = b_old->run_from; b_new->ev_from = b_old->ev_from; b_new->done = 1; return 1; } bl = bl->next; } } // No old binding to connect to return 0; } //! Create a new intruder run to generate knowledge from m0 int bind_goal_new_m0 (const Binding b) { Termlist m0tl, tl; int flag; int found; flag = 1; found = 0; m0tl = knowledgeSet (sys->know); tl = m0tl; while (flag && tl != NULL) { Term m0t; Termlist subst; m0t = tl->term; subst = termMguTerm (b->term, m0t); if (subst != MGUFAIL) { int run; I_M->roledef->message = m0t; run = semiRunCreate (INTRUDER, I_M); proof_suppose_run (run, 0, 1); sys->runs[run].length = 1; { indentDepth++; if (goal_bind (b, run, 0)) { found++; proof_suppose_binding (b); if (switches.output == PROOF) { indentPrint (); eprintf ("* I.e. retrieving "); termPrint (b->term); eprintf (" from the initial knowledge.\n"); } flag = flag && iterate (); } else { proof_cannot_bind (b, run, 0); } goal_unbind (b); indentDepth--; } semiRunDestroy (); termlistSubstReset (subst); termlistDelete (subst); } tl = tl->next; } if (found == 0 && switches.output == PROOF) { indentPrint (); eprintf ("Term "); termPrint (b->term); eprintf (" cannot be constructed from the initial knowledge.\n"); } termlistDelete (m0tl); return flag; } //! Bind an intruder goal by intruder composition construction /** * Handles the case where the intruder constructs a composed term himself. */ int bind_goal_new_encrypt (const Binding b) { Term term; int flag; int can_be_encrypted; flag = 1; term = deVar (b->term); can_be_encrypted = 0; if (!realTermLeaf (term)) { int run; int index; int newgoals; Roledef rd; Term t1, t2; if (!realTermEncrypt (term)) { // tuple construction error ("Goal that is a tuple should not occur!"); } // must be encryption t1 = TermOp (term); t2 = TermKey (term); if (t2 != TERM_Hidden) { can_be_encrypted = 1; run = semiRunCreate (INTRUDER, I_RRS); rd = sys->runs[run].start; rd->message = termDuplicateUV (t1); rd->next->message = termDuplicateUV (t2); rd->next->next->message = termDuplicateUV (term); index = 2; proof_suppose_run (run, 0, index + 1); if (switches.output == PROOF) { indentPrint (); eprintf ("* Encrypting "); termPrint (term); eprintf (" using term "); termPrint (t1); eprintf (" and key "); termPrint (t2); eprintf ("\n"); } newgoals = add_read_goals (run, 0, index + 1); indentDepth++; if (goal_bind (b, run, index)) { proof_suppose_binding (b); flag = flag && iterate (); } else { proof_cannot_bind (b, run, index); } goal_unbind (b); indentDepth--; goal_remove_last (newgoals); semiRunDestroy (); } } if (!can_be_encrypted) { if (switches.output == PROOF) { indentPrint (); eprintf ("Term "); termPrint (b->term); eprintf (" cannot be constructed by encryption.\n"); } } return flag; } //! Bind an intruder goal by intruder construction /** * Handles the case where the intruder constructs a composed term himself, or retrieves it from m0. * However, it must not already have been created in an intruder run; then it gets bound to that. */ int bind_goal_new_intruder_run (const Binding b) { int flag; if (switches.output == PROOF) { indentPrint (); eprintf ("Can we bind "); termPrint (b->term); eprintf (" from a new intruder run?\n"); } indentDepth++; flag = bind_goal_new_m0 (b); flag = flag && bind_goal_new_encrypt (b); indentDepth--; return flag; } //! Bind a regular goal /** * Problem child. Valgrind does not like it. */ int bind_goal_regular_run (const Binding b) { int flag; int found; int test_sub_unification (Termlist substlist, Termlist keylist) { // A unification exists; return the signal return 0; } /* * This is a local function so we have access to goal */ int bind_this_role_send (Protocol p, Role r, Roledef rd, int index) { if (p == INTRUDER) { // No intruder roles here return 1; } // Test for interm unification #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Checking send candidate with message "); termPrint (rd->message); eprintf (" from "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (", index %i\n", index); } #endif if (!termMguSubTerm (b->term, rd->message, test_sub_unification, sys->know->inverses, NULL)) { int sflag; // A good candidate found++; if (switches.output == PROOF && found == 1) { indentPrint (); eprintf ("The term ", found); termPrint (b->term); eprintf (" matches patterns from the role definitions. Investigate.\n"); } if (switches.output == PROOF) { indentPrint (); eprintf ("%i. It matches the pattern ", found); termPrint (rd->message); eprintf (" from "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (", at %i\n", index); } indentDepth++; // Bind to existing run sflag = bind_existing_run (b, p, r, index); // bind to new run sflag = sflag && bind_new_run (b, p, r, index); indentDepth--; return sflag; } else { return 1; } } // Bind to all possible sends of regular runs found = 0; flag = iterate_role_sends (bind_this_role_send); if (switches.output == PROOF && found == 0) { indentPrint (); eprintf ("The term "); termPrint (b->term); eprintf (" does not match any pattern from the role definitions.\n"); } return flag; } // Bind to all possible sends of intruder runs int bind_goal_old_intruder_run (Binding b) { int run; int flag; int found; found = 0; flag = 1; for (run = 0; run < sys->maxruns; run++) { if (sys->runs[run].protocol == INTRUDER) { int ev; Roledef rd; rd = sys->runs[run].start; ev = 0; while (ev < sys->runs[run].length) { if (rd->type == SEND) { found++; if (switches.output == PROOF && found == 1) { indentPrint (); eprintf ("Suppose it is from an existing intruder run.\n"); } indentDepth++; flag = flag && bind_existing_to_goal (b, run, ev); indentDepth--; } rd = rd->next; ev++; } } } if (switches.output == PROOF && found == 0) { indentPrint (); eprintf ("No existing intruder runs to match to.\n"); } return flag; } //! Bind a goal in all possible ways int bind_goal (const Binding b) { if (b->blocked) { error ("Trying to bind a blocked goal!"); } if (!b->done) { int flag; int know_only; Term function; flag = 1; proof_select_goal (b); indentDepth++; // Consider a duplicate goal that we already bound before (C-minimality) // if (1 == 0) if (bind_old_goal (b)) { if (switches.output == PROOF) { indentPrint (); eprintf ("Goal for term "); termPrint (b->term); eprintf (" was bound once before, linking up to #%i, %i.\n", b->run_from, b->ev_from); } flag = flag && iterate (); // Unbind again b->done = 0; indentDepth--; return flag; } else { // Prune: if it is an SK type construct, ready // No regular run will apply SK for you. //!@todo This still needs a lemma, and a more generic (correct) algorithm!! know_only = 0; function = getTermFunction (b->term); if (function != NULL) { if (!inKnowledge (sys->know, function)) { // Prune because we didn't know it before, and it is never subterm-sent if (switches.output == PROOF) { indentPrint (); eprintf ("* Because "); termPrint (b->term); eprintf (" is never sent from a regular run, so we only intruder construct it.\n"); } know_only = 1; } } // Keylevel lemmas: improves on the previous one if (!isPossiblySent (b->term)) { if (switches.output == PROOF) { eprintf ("Rejecting a term as a regular bind because key levels are off: "); termPrint (b->term); if (know_only) { eprintf (" [in accordance with function lemma]"); } else { eprintf (" [stronger than function lemma]"); } eprintf ("\n"); } know_only = 1; } #ifdef DEBUG else { if (DEBUGL (5) && know_only == 1) { eprintf ("Keylevel lemma is weaker than function lemma for term "); termPrint (b->term); eprintf ("\n"); } } #endif proofDepth++; if (know_only) { // Special case: only from intruder flag = flag && bind_goal_old_intruder_run (b); flag = flag && bind_goal_new_intruder_run (b); } else { // Normal case { flag = bind_goal_regular_run (b); } flag = flag && bind_goal_old_intruder_run (b); flag = flag && bind_goal_new_intruder_run (b); } proofDepth--; indentDepth--; return flag; } } else { return 1; } } //! Prune determination because of theorems /** *@returns true iff this state is invalid because of a theorem */ int prune_theorems () { Termlist tl; List bl; int run; // Check all types of the local agents according to the matching type if (!checkTypeLocals (sys)) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because some local variable was incorrectly subsituted.\n"); } return 1; } // Check if all agents are agents (!) run = 0; while (run < sys->maxruns) { Termlist agl; agl = sys->runs[run].agents; while (agl != NULL) { Term agent; agent = deVar (agl->term); if (agent == NULL) { error ("Agent of run %i is NULL", run); } /** * Check whether the agent of the run is of a sensible type. * * @TODO Note that this still needs a lemma. */ { int sensibleagent; sensibleagent = true; if (!realTermLeaf (agent)) { // not a leaf sensibleagent = false; } else { // real leaf if (switches.match == 0 || !isTermVariable (agent)) { // either strict matching, or not a variable, so we should check matching types if (agent->stype == NULL) { // Too generic sensibleagent = false; } else { // Has a type if (!inTermlist (agent->stype, TERM_Agent)) { // but not the right type sensibleagent = false; } } } } if (!sensibleagent) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because the agent "); termPrint (agent); eprintf (" of run %i is not of a compatible type.\n", run); } return 1; } } agl = agl->next; } run++; } // Check if all agents of the main run are valid tl = sys->runs[0].agents; while (tl != NULL) { Term agent; agent = deVar (tl->term); if (!realTermVariable (agent) && inTermlist (sys->untrusted, agent)) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because all agents of the claim run must be trusted.\n"); } return 1; } tl = tl->next; } // Check if the actors of all other runs are not untrusted if (sys->untrusted != NULL) { int run; run = 1; while (run < sys->maxruns) { if (sys->runs[run].protocol != INTRUDER) { if (sys->runs[run].agents != NULL) { Term actor; actor = agentOfRun (sys, run); if (actor == NULL) { error ("Agent of run %i is NULL", run); } if (inTermlist (sys->untrusted, actor)) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because the actor of run %i is untrusted.\n", run); } return 1; } } else { Protocol p; globalError++; eprintf ("Run %i: ", run); role_name_print (run); eprintf (" has an empty agents list.\n"); eprintf ("protocol->rolenames: "); p = (Protocol) sys->runs[run].protocol; termlistPrint (p->rolenames); eprintf ("\n"); error ("Aborting."); globalError--; return 1; } } run++; } } // Check for c-minimality { if (!bindings_c_minimal ()) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because this is not <=c-minimal.\n"); } return 1; } } /** * Check whether the bindings are valid */ bl = sys->bindings; while (bl != NULL) { Binding b; b = bl->data; // Check for "Hidden" interm goals if (termInTerm (b->term, TERM_Hidden)) { // Prune the state: we can never meet this if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because intruder can never construnct "); termPrint (b->term); eprintf ("\n"); } return 1; } // Check for encryption levels /* * if (switches.match < 2 */ if (term_encryption_level (b->term) > max_encryption_level) { // Prune: we do not need to construct such terms if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because the encryption level of "); termPrint (b->term); eprintf (" is too high.\n"); } return 1; } // Check for SK-type function occurrences //!@todo Needs a LEMMA, although this seems to be quite straightforward to prove. // The idea is that functions are never sent as a whole, but only used in applications. if (isTermFunctionName (b->term)) { if (!inKnowledge (sys->know, b->term)) { // Not in initial knowledge of the intruder if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned because the function "); termPrint (b->term); eprintf (" is not known initially to the intruder.\n"); } return 1; } } bl = bl->next; } return 0; } //! Prune determination for bounds /** *@returns true iff this state is invalid for some reason */ int prune_bounds () { Termlist tl; List bl; /* prune for time */ if (passed_time_limit ()) { // Oh no, we ran out of time! if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: ran out of allowed time (-T %i switch)\n", get_time_limit ()); } // Pruned because of time bound! sys->current_claim->timebound = 1; return 1; } /* prune for proof depth */ if (proofDepth > switches.maxproofdepth) { // Hardcoded limit on proof tree depth if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: proof tree too deep: %i (-d %i switch)\n", proofDepth, switches.maxproofdepth); } return 1; } /* prune for trace length */ if (switches.maxtracelength < INT_MAX) { int tracelength; int run; /* compute trace length of current semistate */ tracelength = 0; run = 0; while (run < sys->maxruns) { /* ignore intruder actions */ if (sys->runs[run].protocol != INTRUDER) { tracelength = tracelength + sys->runs[run].step; } run++; } /* test */ if (tracelength > switches.maxtracelength) { // Hardcoded limit on proof tree depth if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: trace too long: %i (-l %i switch)\n", tracelength, switches.maxtracelength); } return 1; } } if (num_regular_runs > switches.runs) { // Hardcoded limit on runs if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: too many regular runs (%i).\n", num_regular_runs); } return 1; } // This needs some foundation. Probably * 2^max_encryption_level //!@todo Fix this bound if ((switches.match < 2) && (num_intruder_runs > ((double) switches.runs * max_encryption_level * 8))) { // Hardcoded limit on iterations if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: %i intruder runs is too much. (max encr. level %i)\n", num_intruder_runs, max_encryption_level); } return 1; } // Limit on exceeding any attack length if (switches.prune == 2 && get_semitrace_length () >= attack_length) { if (switches.output == PROOF) { indentPrint (); eprintf ("Pruned: we already know an attack of length %i.\n", attack_length); } return 1; } // No pruning because of bounds return 0; } //! 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 () { 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 add_claim_specifics (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 } } //! Count a false claim /** * Counts global attacks as well as claim instances. */ void count_false () { sys->attackid++; sys->current_claim->failed = statesIncrease (sys->current_claim->failed); } //------------------------------------------------------------------------ // Main logic core //------------------------------------------------------------------------ //! Check properties int property_check () { int flag; int attack_this; flag = 1; /** * By the way the claim is handled, this automatically means a flaw. */ count_false (); if (switches.output == ATTACK) { if (switches.xml) { xmlOutSemitrace (sys); } else { if (switches.latex == 1) { latexSemiState (); } else { dotSemiState (); } } } // Store attack length if shorter attack_this = get_semitrace_length (); if (attack_this < attack_length) { // Shortest attack attack_length = attack_this; if (switches.output == PROOF) { indentPrint (); eprintf ("New shortest attack found with trace length %i.\n", attack_length); } } return flag; } //! Main recursive procedure for Arachne int iterate () { int flag; flag = 1; if (!prune_theorems ()) { if (!prune_claim_specifics ()) { if (!prune_bounds ()) { Binding b; // Are there any tuple goals? b = select_tuple_goal (); if (b != NULL) { // Expand tuple goal int count; // mark as blocked for iteration binding_block (b); // simply adding will detect the tuple and add the new subgoals count = goal_add (b->term, b->run_to, b->ev_to, b->level); // Show this in output if (switches.output == PROOF) { indentPrint (); eprintf ("Expanding tuple goal "); termPrint (b->term); eprintf (" into %i subgoals.\n", count); } // iterate flag = iterate (); // undo goal_remove_last (count); binding_unblock (b); } else { // No tuple goals; good Binding b; /** * Not pruned: count */ sys->states = statesIncrease (sys->states); /** * Check whether its a final state (i.e. all goals bound) */ b = select_goal (); if (b == NULL) { /* * all goals bound, check for property */ if (switches.output == PROOF) { indentPrint (); eprintf ("All goals are now bound.\n"); } sys->claims = statesIncrease (sys->claims); sys->current_claim->count = statesIncrease (sys->current_claim->count); flag = property_check (); } else { /* * bind this goal in all possible ways and iterate */ flag = bind_goal (b); } } } else { // Pruned because of bound! sys->current_claim->complete = 0; } } } #ifdef DEBUG if (DEBUGL (5) && !flag) { warning ("Flag has turned 0!"); } #endif return flag; } //! Main code for Arachne /** * For this test, we manually set up some stuff. * * But later, this will just iterate over all claims. */ int arachne () { Claimlist cl; int print_send (Protocol p, Role r, Roledef rd, int index) { eprintf ("IRS: "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (", %i, ", index); roledefPrint (rd); eprintf ("\n"); return 1; } int determine_encrypt_max (Protocol p, Role r, Roledef rd, int index) { int tlevel; tlevel = term_encryption_level (rd->message); #ifdef DEBUG if (DEBUGL (3)) { eprintf ("Encryption level %i found for term ", tlevel); termPrint (rd->message); eprintf ("\n"); } #endif if (tlevel > max_encryption_level) max_encryption_level = tlevel; return 1; } /* * set up claim role(s) */ if (switches.runs == 0) { // No real checking. return; } if (sys->maxruns > 0) { error ("Something is wrong, number of runs >0."); } num_regular_runs = 0; num_intruder_runs = 0; max_encryption_level = 0; iterate_role_events (determine_encrypt_max); #ifdef DEBUG if (DEBUGL (1)) { eprintf ("Maximum encryption level: %i\n", max_encryption_level); } #endif fixAgentKeylevels (); indentDepth = 0; proofDepth = 0; cl = sys->claimlist; while (cl != NULL) { /** * Check each claim */ // Skip the dummy claims if (!isTermEqual (cl->type, CLAIM_Empty)) { // Any other claims might be filterered if (switches.filterClaim == NULL || switches.filterClaim == cl->type) { int run; Protocol p; Role r; sys->current_claim = cl; attack_length = INT_MAX; cl->complete = 1; p = (Protocol) cl->protocol; r = (Role) cl->role; if (switches.output == PROOF) { indentPrint (); eprintf ("Testing Claim "); termPrint (cl->type); eprintf (" from "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (" at index %i.\n", cl->ev); } indentDepth++; run = semiRunCreate (p, r); proof_suppose_run (run, 0, cl->ev + 1); add_read_goals (run, 0, cl->ev + 1); /** * Add specific goal info */ add_claim_specifics (cl, roledef_shift (sys->runs[run].start, cl->ev)); #ifdef DEBUG if (DEBUGL (5)) { printSemiState (); } #endif // Iterate iterate (); //! Destroy while (sys->bindings != NULL) { goal_remove_last (1); } while (sys->maxruns > 0) { semiRunDestroy (); } //! Indent back indentDepth--; if (switches.output == PROOF) { indentPrint (); eprintf ("Proof complete for this claim.\n"); } } } // next cl = cl->next; } }