ARSN-362: add implicit deny logic to policy eval tests

lib/policyEvaluator/evaluator.ts

@@ -310,6 +310,7 @@ export function evaluatePolicy(
 }
 
 /**
+ * @deprecated Upgrade to evaluateAllPoliciesV2
  * Evaluate whether a request is permitted under a policy.
  * @param requestContext - Info necessary to
  * evaluate permission
@@ -325,6 +326,16 @@ export function evaluateAllPolicies(
     allPolicies: any[],
     log: Logger,
 ): string {
+    return evaluateAllPoliciesV2(requestContext, allPolicies, log).verdict;
+}
+export function evaluateAllPoliciesV2(
+    requestContext: RequestContext,
+    allPolicies: any[],
+    log: Logger,
+): {
+    verdict: string;
+    isImplicit: boolean;
+} {
     log.trace('evaluating all policies');
     let allow = false;
     let allowWithTagCondition = false;
@@ -333,7 +344,10 @@ export function evaluateAllPolicies(
         const singlePolicyVerdict = evaluatePolicy(requestContext, allPolicies[i], log);
         // If there is any Deny, just return Deny
         if (singlePolicyVerdict === 'Deny') {
-            return 'Deny';
+            return {
+                verdict: 'Deny',
+                isImplicit: false,
+            };
         }
         if (singlePolicyVerdict === 'Allow') {
             allow = true;
@@ -344,6 +358,7 @@ export function evaluateAllPolicies(
         } // else 'Neutral'
     }
     let verdict;
+    let isImplicit = false;
     if (allow) {
         if (denyWithTagCondition) {
             verdict = 'NeedTagConditionEval';
@@ -355,8 +370,9 @@ export function evaluateAllPolicies(
             verdict = 'NeedTagConditionEval';
         } else {
             verdict = 'Deny';
+            isImplicit = true;
         }
     }
-    log.trace('result of evaluating all policies', { verdict });
-    return verdict;
+    log.trace('result of evaluating all policies', { verdict, isImplicit });
+    return { verdict, isImplicit };
 }

tests/unit/policyEvaluator.spec.js

@@ -6,6 +6,7 @@ const fakeTimers = require('@sinonjs/fake-timers');
 const evaluator = require('../../lib/policyEvaluator/evaluator');
 const evaluatePolicy = evaluator.evaluatePolicy;
 const evaluateAllPolicies = evaluator.evaluateAllPolicies;
+const evaluateAllPoliciesV2 = evaluator.evaluateAllPoliciesV2;
 const handleWildcards =
     require('../../lib/policyEvaluator/utils/wildcards').handleWildcards;
 const substituteVariables =
@@ -1451,6 +1452,49 @@ describe('policyEvaluator', () => {
             assert.strictEqual(result, 'Deny');
         });
 
+        it('should deny access if any policy results in a Deny', () => {
+            requestContext = new RequestContext({}, {},
+                'my_favorite_bucket', undefined,
+                undefined, undefined, 'bucketDelete', 's3');
+            requestContext.setRequesterInfo({});
+            const result = evaluateAllPoliciesV2(requestContext,
+                [samples['arn:aws:iam::aws:policy/AmazonS3FullAccess'],
+                    samples['Deny Bucket Policy']], log);
+            assert.deepStrictEqual(result, {
+                verdict: 'Deny',
+                isImplicit: false,
+            });
+        });
+
+        it('should deny access if request action is not in any policy', () => {
+            requestContext = new RequestContext({}, {},
+                'notVeryPrivate', undefined,
+                undefined, undefined, 'bucketDelete', 's3');
+            requestContext.setRequesterInfo({});
+            const result = evaluateAllPoliciesV2(requestContext,
+                [samples['Multi-Statement Policy'],
+                    samples['Variable Bucket Policy']], log);
+            assert.deepStrictEqual(result, {
+                verdict: 'Deny',
+                isImplicit: true,
+            });
+        });
+
+        it('should deny access if request resource is not in any policy', () => {
+            requestContext = new RequestContext({}, {},
+                'notbucket', undefined,
+                undefined, undefined, 'objectGet', 's3');
+            requestContext.setRequesterInfo({});
+            const result = evaluateAllPoliciesV2(requestContext, [
+                samples['Multi-Statement Policy'],
+                samples['Variable Bucket Policy'],
+            ], log);
+            assert.deepStrictEqual(result, {
+                verdict: 'Deny',
+                isImplicit: true,
+            });
+        });
+
         const TestMatrixPolicies = {
             Allow: {
                 Version: '2012-10-17',
@@ -1504,6 +1548,136 @@ describe('policyEvaluator', () => {
             },
         };
 
+        const TestMatrixV2 = [
+            {
+                policiesToEvaluate: [],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: true,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Allow',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Neutral'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: true,
+                },
+            },
+            {
+                policiesToEvaluate: ['Deny'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow', 'Allow'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Allow',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow', 'Neutral'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Allow',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Neutral', 'Allow'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Allow',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Neutral', 'Neutral'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: true,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow', 'Deny'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['AllowWithTagCondition'],
+                expectedPolicyEvaluation: {
+                    verdict: 'NeedTagConditionEval',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow', 'AllowWithTagCondition'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Allow',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['DenyWithTagCondition'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: true,
+                },
+            },
+            {
+                policiesToEvaluate: ['Allow', 'DenyWithTagCondition'],
+                expectedPolicyEvaluation: {
+                    verdict: 'NeedTagConditionEval',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['AllowWithTagCondition', 'DenyWithTagCondition'],
+                expectedPolicyEvaluation: {
+                    verdict: 'NeedTagConditionEval',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['AllowWithTagCondition', 'DenyWithTagCondition', 'Deny'],
+                expectedPolicyEvaluation: {
+                    verdict: 'Deny',
+                    isImplicit: false,
+                },
+            },
+            {
+                policiesToEvaluate: ['DenyWithTagCondition', 'AllowWithTagCondition', 'Allow'],
+                expectedPolicyEvaluation: {
+                    verdict: 'NeedTagConditionEval',
+                    isImplicit: false,
+                },
+            },
+        ];
+
+        TestMatrixV2.forEach(testCase => {
+            it(`policies evaluating individually to [${testCase.policiesToEvaluate.join(', ')}] `
+            + `should return ${testCase.expectedPolicyEvaluation}`, () => {
+                requestContext = new RequestContext({}, {},
+                    'my_favorite_bucket', undefined,
+                    undefined, undefined, 'objectGet', 's3');
+                requestContext.setRequesterInfo({});
+                const result = evaluateAllPoliciesV2(
+                    requestContext,
+                    testCase.policiesToEvaluate.map(policyName => TestMatrixPolicies[policyName]),
+                    log);
+                assert.deepStrictEqual(result, testCase.expectedPolicyEvaluation);
+            });
+        });
+
         const TestMatrix = [
             {
                 policiesToEvaluate: [],