1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 | 2× 2× 2× 2× 2× 2× 2× 401× 38× 401× 57× 382× 2× 38× 38× 38× 2× 361× 361× 361× 361× 266× 361× 361× 361× 361× 361× 361× 2× 19× 20× 38× 2× 38× 2× 19× 2× 1× 1× 1× 2× 19× 19× 19× 19× 19× 19× 1× 19× 19× 19× 19× 19× 19× 19× 19× 19× 19× 19× 1× 1× 3× 3× 1× 1× 3× 1× 1× 3× 3× 3× 3× 3× 2× 19× 19× 19× 19× 19× 19× 19× 19× 19× 95× 19× 19× 19× 19× 19× 19× 38× 19× 228× 19× 38× 19× 19× 266× 19× 19× | 'use strict'; const _ = require('lodash'); const URL = require('url'); const Q = require('q'); const classification = require(__dirname + '/classification'); // all functions here are unary, so that they may "pre-compile" const matches = { 'equal' : v => { const v_low = v.toLowerCase(); return (ua => ua === v_low); }, 'not_equal': v => { const v_low = v.toLowerCase(); return (ua => ua !== v_low); }, 'contains': v => { const v_low = v.toLowerCase(); return (ua => ua.indexOf(v_low) >= 0); }, 'starts_with': v => { const v_low = v.toLowerCase(); return (ua => ua.startsWith(v_low)); }, 'ends_with': v => { const v_low = v.toLowerCase(); return (ua => ua.endsWith(v_low)); }, // cannot lowercase v, need to tell RegExp to ignore case instead 'regex': v => RegExp.prototype.test.bind(new RegExp(v, 'i')) }; // not_allowed is the UI artifact. It is used in exit mode (upgrade_action) and // it means the transition from entry mode is not allowed. To me this is no // different from specifying upgrade_action==entry_action, and that's what I // translate them to using max(). const actionMap = {not_allowed: 0, block: 1, read_only: 2, read_write: 3, direct: 4 }; /** * @function* explanations * @desc Given a Tally-like object with score, produces a list of any * explanations from this Tally-like, or any nested Tally-like from the trace. * * Assumes tally is either primitive, or an object that may contain score, * explain or trace attributes. * * @param {any} tally - a primitive, or a Tally-like object to traverse * @yield {[Int, object]} produces pairs of [Int, object], where the head item * represents the score, and the last item an object that represents the * explanation */ function* explanations(tally) { if (tally.explain) { yield [tally.score, tally.explain]; } if (tally.trace) { for(let t in tally.trace) { yield* explanations(tally.trace[t]); } } } const Tally = function() { const self = this; self.score = 0; self.trace = {}; }; // tally can add the score from a given function or Tally or number Tally.prototype.tally = function(f) { const self = this; // FIXME: that's what ...rest is for, but our version of node doesn't support // that at the moment const rest = Array.from(arguments).slice(1); const name = typeof f === 'string' ? f: undefined; if (name !== undefined) { f = rest.shift(); } const tally = typeof f === 'function' ? f.apply(null, rest): f; const score = typeof tally === 'object'? tally.score: tally; Iif (typeof score !== 'number') { throw new Error(tally.error.toString() || 'Expected Tally-like, but found score is ' + typeof score + '; keys: ' + Object.keys(tally)); } self.score += score; self.trace[name || f.displayName || f.name || 'noname'] = tally; return self; }; /** * @function explanations * @desc Traverses this Tally and any nested Tally-like in trace to obtain * an array of explanations, where they are available, sorted in descending * order of the classification score. */ Tally.prototype.explanations = function() { return Array.from(explanations(this)) .sort((a,b) => b[0]-a[0]) .map(a => a[1]); }; // looks at x and returns either left(x.left) if not x.right, or right(x.right) function either(x, left, right) { return x.right ? right(x.right): left(x.left); } // Copies x, and adds fields from object produced by f, if x.right. // If not x.right, just returns x. function rightDefaults(x, f) { return either(x, () => x, (r) => _.defaults(f(r) || {}, x)); } // This function validates subject_rules and produces {right:...} // at each level of nesting for valid rules, and {left: 'diagnostic message'} // for rules that contain references to unknown matchers function validateSubjectRules(subject_rules) { return subject_rules.map( s_rule => { const match = {'all' : _.every, 'any' : _.some}[s_rule.match]; return _.defaults(match && { right: match, rules: s_rule.subject_attributes.map( r_spec => { const fn = matches[r_spec.relation]; let fn_ap; try { fn_ap = fn && fn(r_spec.value); }catch(e) { fn_ap = undefined; } return _.defaults( fn_ap && {right: fn_ap, attribute: r_spec.attribute.toLowerCase()} || fn && {left: 'Bad constant "' + r_spec.value + '" for relation: ' + r_spec.relation} || {left: 'Unknown relation: ' + r_spec.relation}, r_spec); }), id: s_rule.id } || {left: 'Unknown match: ' + s_rule.match}, s_rule); }); } module.exports = { policyUserAttributes: safemailPolicy => _.uniq(_.flatten( safemailPolicy.subject_rules.map( s_rule => _.map(s_rule.subject_attributes, 'attribute') ) )), validateSubjectRules: validateSubjectRules, pdp: (urlScore, attributeSearchResult, safemailPolicy) => { Iif (!attributeSearchResult) { attributeSearchResult = {}; } Iif (!attributeSearchResult.attributes) { attributeSearchResult.attributes = []; } Iif (!urlScore || !urlScore.riskScore || !safemailPolicy) { return {error: 'URL score and safemail policy are required', url_score: urlScore, attribute_search_result: attributeSearchResult}; } // produce a structure of the policy that represents a trace of // role assignment decision-making. // the principle is simple: if the section is applicable, it is mapped // to {right: ...}; if there is a problem or the rule cannot be evaluated, // it is mapped to {left: 'diagnostic message'} if (!safemailPolicy.validated_subject_rules) { safemailPolicy.validated_subject_rules = validateSubjectRules(safemailPolicy.subject_rules); } const userAttributes = {}; Object.keys(attributeSearchResult.attributes).forEach( k => { userAttributes[k.toLowerCase()] = attributeSearchResult. attributes[k].map(v => v.toLowerCase()); } ); const valid_rules = safemailPolicy.validated_subject_rules; // applicable rules is a copy of valid_rules with ua filled in for each // s_rule.r_spec with right for which we have found userAttributes, // or left with an diagnostic message const applicable_rules = valid_rules.map( s_rule => rightDefaults(s_rule, () => ({rules: s_rule.rules.map( r_spec => rightDefaults(r_spec, () => ({ua: userAttributes[r_spec.attribute] && userAttributes[r_spec.attribute].length > 0 && {right: userAttributes[r_spec.attribute]} || {left: 'No value for attribute: ' + r_spec.attribute} }))) })) ); const userRole = applicable_rules.find( s_rule => either(s_rule, () => false, match => match(s_rule.rules, rule => rule.right && rule.ua.right && rule.ua.right.some(rule.right) ) ) ); Iif (!userRole) { // TODO: the policy should contain default role return {error: 'User does not match any role. Assume default action.', url_score: urlScore, attribute_search_result: attributeSearchResult, role_assignment_policy_trace: applicable_rules}; } if (!safemailPolicy.validated_action_map && safemailPolicy.entry_actions){ safemailPolicy.validated_action_map = {}; safemailPolicy.entry_actions.forEach(action => { let c = safemailPolicy .validated_action_map[action.subject_rule_id]; if (!c) { c = {}; safemailPolicy.validated_action_map[action.subject_rule_id]=c; } c[action.risk_score] = { entry_action: action.isolation_action in actionMap && action.isolation_action, user_experience_banner: action.user_experience_banner }; }); Eif (safemailPolicy.upgrade_actions) { safemailPolicy.upgrade_actions.forEach(action => { let c = safemailPolicy .validated_action_map[action.subject_rule_id]; Iif (!c) { c = {}; safemailPolicy.validated_action_map[action.subject_rule_id]=c; } Iif (!c[action.risk_score]) { c[action.risk_score] = {}; } const rs = c[action.risk_score]; rs.upgrade_action = action.isolation_action in actionMap && action.isolation_action; }); } } function max(a1, a2) { return (actionMap[a1] || 0) > (actionMap[a2] || 0) ? a1: a2; } const riskScore = urlScore.riskScore; const actions = safemailPolicy.validated_action_map[userRole.id] || {}; const riskScoreAction = actions[riskScore] || {}; const entry_action = riskScoreAction.entry_action || 'block'; const upgrade_action_rule = riskScoreAction.upgrade_action || 'block'; const upgrade_action = max(entry_action, upgrade_action_rule); return {decision: { selected_rule: userRole.id, user_experience_banner: riskScoreAction.user_experience_banner|| 'basic', entry_action: entry_action, upgrade_action: upgrade_action }, url_score: urlScore, attribute_search_result: attributeSearchResult, role_assignment_policy_trace: applicable_rules}; }, uceToTally: uceResponse => { const t = classification.uceClassifiers.reduce( (acc, classifier) => acc.tally(classifier, uceResponse), new Tally() ); t.uceResponse = uceResponse; return t; }, countryCodeToTally: cs => classification.countryScore(cs), // Asynchronously collects scores from all classifiers. May skip waiting for // some classifiers, if the risk score can be shown to not change. Place the // slowest responding asynchronous classifiers first, the synchronous ones // last. riskScore: (asyncs, urlString) => { try { // parts of URL may be case-sensitive (like path), // but for this analysis we don't need to distinguish that const url = URL.parse(urlString.toLowerCase()); // fire off async classifiers, and compute sync classifier scores // asyncClassifiers: [Q([string, Tally|int])] // syncClassifiers: [[string, Tally|int]] const asyncClassifiers = asyncs.map( c => Q.all([c.displayName || c.name, c(url)] )); // urlClassifiers: [URL -> Tally|int] const syncClassifiers = classification.urlClassifiers.map( c => [c.displayName || c.name, c(url)] ); // lazyScore: Q(either any Tally) // folding the array of classifiers permits to build a computation that // stops evaluating the chain once tally reaches HIGH_RISK_THRESHOLD. // good URLs (that is, most of the URLs) will wait for all classifiers // to provide a score, so we use Q.all as it is much simpler. // TODO: do we care to complicate this logic for bad URLs to possibly // get a score sooner? This should affect only really bad URLs. const lazyScore = Q.all(asyncClassifiers) .then(scores => { Eif (scores.every(c => c[1] !== undefined && c[1].score !== undefined)) { return scores; } else { // replacing all failed asynchronous classifiers // with a single risk score - needed for UCE as // per UK-412 return scores .filter(c => c[1] !== undefined && c[1].score !== undefined) .concat([['failed_async', classification.MED_RISK_THRESHOLD - 1]]); } }) .then(scores => syncClassifiers.concat(scores) .reduce( // (Tally, [string, Tally|()->Tally]) -> Tally (acc, score) => acc.tally.apply(acc, score), new Tally() ) ) .then(tally => ({ riskScore: tally.score < classification.MED_RISK_THRESHOLD? 'low': tally.score < classification.HIGH_RISK_THRESHOLD? 'medium': 'high', tally: tally }) ); // .fail to be handled by the caller return lazyScore; } catch(e) { return Q.Promise((resolve, reject) => reject(e)); } } }; |