/** *@file arachne.c * * Introduces a method for proofs akin to the Athena modelchecker * http://www.ece.cmu.edu/~dawnsong/athena/ * */ #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 "error.h" #include "claim.h" #include "debug.h" #include "binding.h" extern Term CLAIM_Secret; extern Term CLAIM_Nisynch; extern Term CLAIM_Niagree; extern Term TERM_Agent; static System sys; Protocol INTRUDER; // Pointers, to be set by the Init Role I_GOAL; // Same here. Role I_TEE; Role I_SPLIT; Role I_TUPLE; Role I_ENCRYPT; Role I_DECRYPT; Role I_M0; static int indentDepth; #ifdef DEBUG static char *explanation; // Pointer to a string that describes what we just tried to do static int e_run; static Term e_term1; static Term e_term2; static Term e_term3; #endif struct goalstruct { int run; int index; Roledef rd; }; typedef struct goalstruct Goal; /** * Forward declarations */ int iterate (); /** * Program code */ //! Init Arachne engine void arachneInit (const System mysys) { Roledef rd = NULL; 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 ")); add_event (READ, NULL); I_GOAL = add_role (" I_GOAL "); add_event (SEND, NULL); I_M0 = add_role (" I_M0 "); 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 print void indentPrint () { #ifdef DEBUG int i; for (i = 0; i < indentDepth; i++) eprintf ("%i ", i); #else eprintf (">> "); #endif } //! Iterate but discard the info of the termlist int mgu_iterate (const Termlist tl) { return iterate (); } //! 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 && tl->term->right.runid == -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 = t->right.runid; } else { // Specific run: compare if (run != t->right.runid) { return -1; } } } } tl = tl->next; } return run; } //------------------------------------------------------------------------ // Sub //------------------------------------------------------------------------ //! 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) ()) { 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 (rd->type == SEND) { if (!func (p, r, rd, index)) return 0; } index++; rd = rd->next; } r = r->next; } p = p->next; } return 1; } //! Generate a new intruder goal int create_intruder_goal (Term t) { int run; Roledef rd; roleInstance (sys, INTRUDER, I_GOAL, NULL, NULL); run = sys->maxruns - 1; rd = sys->runs[run].start; sys->runs[run].length = 1; rd->message = termDuplicate (t); #ifdef DEBUG if (DEBUGL (3)) { explanation = "Adding intruder goal for message "; e_term1 = t; e_run = run; } #endif return run; } //! Generates a new intruder goal, iterates /** * Sloppy, does not unify term but hardcodes it into the stuff. */ int add_intruder_goal_iterate (Goal goal) { int flag; int run; run = create_intruder_goal (goal.rd->message); if (binding_add (run, 0, goal.run, goal.index)) { flag = iterate (); } else { indentPrint (); eprintf ("Aborted adding intruder goal because of cycle.\n"); flag = 1; } binding_remove_last (); roleInstanceDestroy (sys); // destroy the created run return flag; } //! Try to bind a specific existing run to a goal. /** * The key goals are bound to the goal. *@param subterm determines whether it is a subterm unification or not. */ int bind_existing_to_goal (const Goal goal, const int index, const int run, const int subterm) { Roledef rd; int flag; int old_length; int subterm_iterate (Termlist substlist, Termlist keylist) { int keycount; int flag; #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Adding key list : "); termlistPrint (keylist); eprintf ("\n"); } #endif flag = 1; keycount = 0; while (flag && keylist != NULL) { int keyrun; keyrun = create_intruder_goal (keylist->term); if (!binding_add (keyrun, 0, goal.run, goal.index)) flag = 0; keylist = keylist->next; keycount++; } flag = flag && iterate (); while (keycount > 0) { binding_remove_last (); roleInstanceDestroy (sys); keycount--; } termlistDestroy (keylist); return flag; } int interm_iterate (Termlist substlist) { iterate (); } //---------------------------- // Roledef entry rd = roledef_shift (sys->runs[run].start, index); // Fix length old_length = sys->runs[run].length; if ((index + 1) > old_length) sys->runs[run].length = index + 1; #ifdef DEBUG if (DEBUGL (3)) { explanation = "Bind existing run (generic) "; e_run = run; e_term1 = goal.rd->message; e_term2 = rd->message; } #endif if (binding_add (run, index, goal.run, goal.index)) { if (subterm) { flag = termMguSubTerm (goal.rd->message, rd->message, subterm_iterate, sys->know->inverses, NULL); } else { flag = termMguInTerm (goal.rd->message, rd->message, interm_iterate); } } else { #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Aborted binding existing run because of cycle.\n"); } #endif } binding_remove_last (); // Reset length sys->runs[run].length = old_length; return flag; } //! Bind a goal to an existing regular run, if possible int bind_existing_run (const Goal goal, const Protocol p, const Role r, const int index, const int subterm) { int run, flag; #ifdef DEBUG if (DEBUGL (4)) { indentPrint (); eprintf ("Trying to bind "); termPrint (goal.rd->message); eprintf (" to an existing instance of "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (" (%i)\n", subterm); } #endif flag = 1; for (run = 0; run < sys->maxruns; run++) { if (sys->runs[run].protocol == p && sys->runs[run].role == r) { flag = flag && bind_existing_to_goal (goal, index, run, subterm); } } return flag; } //! Bind a goal to a new run int bind_new_run (const Goal goal, const Protocol p, const Role r, const int index, const int subterm) { int run; int flag; roleInstance (sys, p, r, NULL, NULL); run = sys->maxruns - 1; #ifdef DEBUG if (DEBUGL (4)) { indentPrint (); eprintf ("Trying to bind "); termPrint (goal.rd->message); eprintf (" to a new instance of "); termPrint (p->nameterm); eprintf (", "); termPrint (r->nameterm); eprintf (", run %i (subterm:%i)\n", run, subterm); } #endif flag = bind_existing_to_goal (goal, index, run, subterm); roleInstanceDestroy (sys); return flag; } //! Print the current semistate void printSemiState () { int run; int open; List bl; int binding_indent_print (void *data) { indentPrint (); eprintf ("!! "); binding_print (data); return 1; } indentPrint (); eprintf ("!! --=[ Semistate ]=--\n"); 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_indent_print); } indentPrint (); eprintf ("!!\n"); indentPrint (); eprintf ("!! - open: %i -\n", open); } //------------------------------------------------------------------------ // Larger logical componentents //------------------------------------------------------------------------ //! Goal selection /** * Should be ordered to prefer most constrained; for now, it is simply the first one encountered. */ Goal select_goal () { Goal goal; int run; goal.run = INVALID; goal.rd = NULL; for (run = 0; run < sys->maxruns; run++) { Roledef rd; int index; index = 0; rd = sys->runs[run].start; while (rd != NULL && index < sys->runs[run].length) { if (isGoal (rd) && !isBound (rd)) { // Return this goal goal.run = run; goal.index = index; goal.rd = rd; return goal; } index++; rd = rd->next; } } return goal; } //! Bind a regular goal int bind_goal_regular (const Goal goal) { int flag; /* * This is a local function so we have access to goal */ int bind_this_role_send (Protocol p, Role r, Roledef rd, int index) { int test_unification (Termlist substlist) { // A unification exists; return the signal return 0; } if (p == INTRUDER) { /* only bind to regular runs */ return 1; } else { // 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 (!termMguInTerm (goal.rd->message, rd->message, test_unification)) { // A good candidate #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Term "); termPrint (goal.rd->message); eprintf (" can possibly be bound by role "); termPrint (r->nameterm); eprintf (", index %i\n", index); } #endif return (bind_new_run (goal, p, r, index, 0) && bind_existing_run (goal, p, r, index, 0)); } else { // Cannot unify: no attacks return 1; } } } // Bind to all possible sends or intruder node; #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Try regular role send.\n"); } #endif flag = iterate_role_sends (bind_this_role_send); #ifdef DEBUG if (DEBUGL (5)) { indentPrint (); eprintf ("Try intruder send.\n"); } #endif return (flag && add_intruder_goal_iterate (goal)); } //! Bind an intruder goal to a regular run int bind_intruder_to_regular (Goal goal) { int bind_this_roleevent (Protocol p, Role r, Roledef rd, int index) { int cannotUnify; int test_unification (Termlist substlist, Termlist keylist) { // Signal that unification is possible. return 0; } /** * Note that we only bind to regular runs here */ if (p == INTRUDER) { return 1; // don't abort scans } else { // Test for subterm unification if (termMguSubTerm (goal.rd->message, rd->message, test_unification, sys->know->inverses, NULL)) { // cannot unify return 1; } else { /** * Either from an existing, or from a new run. */ return (bind_new_run (goal, p, r, index, 1) && bind_existing_run (goal, p, r, index, 1)); } } } // Bind to all possible sends? return iterate_role_sends (bind_this_roleevent); } //! Bind an intruder goal by intruder construction /** * Handles the case where the intruder constructs a composed term himself. */ int bind_intruder_to_construct (const Goal goal) { Term term; Termlist m0tl; int flag; int run; flag = 1; term = goal.rd->message; /** * Two options. * * 1. Constructed from composite terms */ if (!realTermLeaf (term)) { Term t1, t2; if (realTermTuple (term)) { // tuple construction t1 = term->left.op1; t2 = term->right.op2; } else { // must be encryption t1 = term->left.op; t2 = term->right.key; } run = create_intruder_goal (t1); if (binding_add (run, 0, goal.run, goal.index)) { run = create_intruder_goal (t2); if (binding_add (run, 0, goal.run, goal.index)) { flag = flag && iterate (); } binding_remove_last (); roleInstanceDestroy (sys); } binding_remove_last (); roleInstanceDestroy (sys); } /** * 2. Retrieved from M_0 */ m0tl = knowledgeSet (sys->know); while (flag && m0tl != NULL) { Term m0t; Termlist subst; m0t = m0tl->term; subst = termMguTerm (term, m0t); if (subst != MGUFAIL) { int run; roleInstance (sys, INTRUDER, I_M0, NULL, NULL); run = sys->maxruns - 1; sys->runs[run].start->message = termDuplicate(term); sys->runs[run].length = 1; if (binding_add (run, 0, goal.run, goal.index)) { #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Retrieving "); termPrint (term); eprintf (" from the initial knowledge.\n"); } #endif iterate (); } binding_remove_last (); roleInstanceDestroy (sys); termlistSubstReset (subst); termlistDelete (subst); } m0tl = m0tl->next; } termlistDelete (m0tl); /** * return result */ return flag; } //! Bind an intruder goal /** * Computes F2 as in Athena explanations. */ int bind_goal_intruder (const Goal goal) { /** * Special case: when the intruder can bind it to the initial knowledge. */ Termlist tl; int flag; flag = 1; tl = knowledgeSet (sys->know); while (flag && tl != NULL) { int hasvars; Termlist substlist; substlist = termMguTerm (tl->term, goal.rd->message); if (substlist != MGUFAIL) { // This seems to work flag = flag && iterate (); termlistSubstReset (substlist); termlistDelete (substlist); } tl = tl->next; } termlistDelete (tl); return (flag && bind_intruder_to_regular (goal) && bind_intruder_to_construct (goal)); } //! Bind a goal in all possible ways int bind_goal (const Goal goal) { if (!goal.rd->bound) { int flag; goal.rd->bound = 1; if (sys->runs[goal.run].protocol == INTRUDER) { flag = bind_goal_intruder (goal); } else { flag = bind_goal_regular (goal); } goal.rd->bound = 0; return flag; } else { return 1; } } //! Prune determination /** *@returns true iff this state is invalid for some reason */ int prune () { Termlist tl; if (indentDepth > 20) { // Hardcoded limit on iterations #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Pruned because too many iteration levels.\n"); } #endif return 1; } if (sys->maxruns > sys->switchRuns) { // Hardcoded limit on runs #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Pruned because too many runs.\n"); } #endif return 1; } // Check if all agents are valid tl = sys->runs[0].agents; while (tl != NULL) { Term agent; agent = deVar (tl->term); if (!realTermLeaf (agent)) { #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Pruned because agent cannot be compound term.\n"); } #endif return 1; } if (!inTermlist (agent->stype, TERM_Agent)) { #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Pruned because agent must contain agent type.\n"); } #endif return 1; } if (!realTermVariable (agent) && inTermlist (sys->untrusted, agent)) { #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Pruned because all agents of the claim run must be trusted.\n"); } #endif return 1; } tl = tl->next; } return 0; } //! Setup system for specific claim test add_claim_specifics (Claimlist cl, Roledef rd) { if (cl->type == CLAIM_Secret) { /** * Secrecy claim */ create_intruder_goal (rd->message); } } //------------------------------------------------------------------------ // Main logic core //------------------------------------------------------------------------ //! Main recursive procedure for Arachne int iterate () { int flag; Goal goal; flag = 1; indentDepth++; if (!prune ()) { /** * Not pruned: count */ sys->states = statesIncrease (sys->states); #ifdef DEBUG if (DEBUGL (3) && explanation != NULL) { indentDepth--; indentPrint (); indentDepth++; eprintf ("ITERATE: %s", explanation); if (e_run != INVALID) eprintf ("#%i ", e_run); if (e_term1 != NULL) { termPrint (e_term1); eprintf (" "); } if (e_term2 != NULL) { termPrint (e_term2); eprintf (" "); } if (e_term3 != NULL) { termPrint (e_term3); eprintf (" "); } eprintf (" ]}>=--\n"); } #endif /** * Check whether its a final state (i.e. all goals bound) */ goal = select_goal (); if (goal.run == INVALID) { /* * all goals bound, check for property */ sys->claims = statesIncrease (sys->claims); #ifdef DEBUG if (DEBUGL (3)) { printSemiState (); } #endif //!@todo Property check in Arachne. } else { #ifdef DEBUG if (DEBUGL (3)) { indentPrint (); eprintf ("Trying to bind goal "); termPrint (goal.rd->message); eprintf (" from run %i, index %i.\n", goal.run, goal.index); } #endif /* * bind this goal in all possible ways and iterate */ flag = bind_goal (goal); } } #ifdef DEBUG explanation = NULL; e_run = INVALID; e_term1 = NULL; e_term2 = NULL; e_term3 = NULL; #endif indentDepth--; 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; /* * set up claim role(s) */ if (sys->maxruns > 0) { error ("Something is wrong, number of runs >0."); } 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"); } #ifdef DEBUG if (DEBUGL (1)) { iterate_role_sends (print_send); } #endif indentDepth = 0; cl = sys->claimlist; while (cl != NULL) { /** * Check each claim */ Protocol p; Role r; if (sys->switchClaimToCheck == NULL || sys->switchClaimToCheck == cl->type) { #ifdef DEBUG explanation = NULL; e_run = INVALID; e_term1 = NULL; e_term2 = NULL; e_term3 = NULL; #endif p = (Protocol) cl->protocol; r = (Role) cl->role; #ifdef DEBUG if (DEBUGL (2)) { indentPrint (); eprintf ("Testing Claim "); termPrint (cl->type); eprintf (" in protocol "); termPrint (p->nameterm); eprintf (", role "); termPrint (r->nameterm); eprintf (" at index %i.\n", cl->ev); } #endif roleInstance (sys, p, r, NULL, NULL); sys->runs[0].length = cl->ev + 1; /** * Add specific goal info */ add_claim_specifics (cl, roledef_shift (sys->runs[0].start, cl->ev)); #ifdef DEBUG if (DEBUGL (5)) { printSemiState (); } #endif /* * iterate */ iterate (); //! Destroy while (sys->maxruns > 0) { roleInstanceDestroy (sys); } } // next cl = cl->next; } }