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semmle-qlci merged 3 commits into from Sep 26, 2018
Merged

JS: add ad hoc whitelist checks as sanitizers #230

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42fc28b
JS: add ad hoc whitelist checks as sanitizers
Sep 24, 2018
52061b3
JS: address review comments: improve regex, limit sanitizer usage
Sep 26, 2018
097a281
JS: change notes for AdHocWhitelistCheckSanitizer
Sep 26, 2018
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2 changes: 2 additions & 0 deletions change-notes/1.19/analysis-javascript.md
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Expand Up @@ -4,6 +4,8 @@

* Modelling of taint flow through array operations has been improved. This may give additional results for the security queries.

* The taint tracking library now recognizes additional sanitization patterns. This may give fewer false-positive results for the security queries.

* Support for popular libraries has been improved. Consequently, queries may produce more results on code bases that use the following features:
- file system access, for example through [fs-extra](https://github.com/jprichardson/node-fs-extra) or [globby](https://www.npmjs.com/package/globby)

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20 changes: 20 additions & 0 deletions javascript/ql/src/semmle/javascript/dataflow/TaintTracking.qll
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Expand Up @@ -625,6 +625,26 @@ module TaintTracking {

}

/**
* A check of the form `if(<isWhitelisted>(x))`, which sanitizes `x` in its "then" branch.
*
* `<isWhitelisted>` is a call with callee name 'safe', 'whitelist', 'allow', or similar.
*
* This sanitizer is not enabled by default.
*/
class AdHocWhitelistCheckSanitizer extends SanitizerGuardNode, DataFlow::CallNode {
AdHocWhitelistCheckSanitizer() {
getCalleeName().regexpMatch("(?i).*((?<!un)safe|whitelist|allow|(?<!un)auth(?!or\\b)).*") and
getNumArgument() = 1
}

override predicate sanitizes(boolean outcome, Expr e) {
outcome = true and
e = getArgument(0).asExpr()
}

}

/** A check of the form `if(x in o)`, which sanitizes `x` in its "then" branch. */
class InSanitizer extends AdditionalSanitizerGuardNode, DataFlow::ValueNode {

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5 changes: 5 additions & 0 deletions javascript/ql/src/semmle/javascript/security/dataflow/CorsMisconfigurationForCredentials.qll
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Expand Up @@ -49,6 +49,11 @@ module CorsMisconfigurationForCredentials {
super.isSanitizer(node) or
node instanceof Sanitizer
}

override predicate isSanitizerGuard(TaintTracking::SanitizerGuardNode guard) {
guard instanceof TaintTracking::AdHocWhitelistCheckSanitizer
}

}

/** A source of remote user input, considered as a flow source for CORS misconfiguration. */
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5 changes: 5 additions & 0 deletions javascript/ql/test/library-tests/TaintBarriers/ExampleConfiguration.qll
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Expand Up @@ -23,4 +23,9 @@ class ExampleConfiguration extends TaintTracking::Configuration {
)
}

override predicate isSanitizerGuard(TaintTracking::SanitizerGuardNode guard) {
// add additional generic sanitizers
guard instanceof TaintTracking::AdHocWhitelistCheckSanitizer
}

}
2 changes: 2 additions & 0 deletions javascript/ql/test/library-tests/TaintBarriers/SanitizingGuard.expected
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Expand Up @@ -36,3 +36,5 @@
| tst.js:214:9:214:24 | o.indexOf(v) < 0 | ExampleConfiguration | false | tst.js:214:19:214:19 | v |
| tst.js:220:9:220:25 | o.indexOf(v) > -1 | ExampleConfiguration | true | tst.js:220:19:220:19 | v |
| tst.js:226:9:226:26 | -1 >= o.indexOf(v) | ExampleConfiguration | false | tst.js:226:25:226:25 | v |
| tst.js:236:9:236:24 | isWhitelisted(v) | ExampleConfiguration | true | tst.js:236:23:236:23 | v |
| tst.js:240:9:240:28 | config.allowValue(v) | ExampleConfiguration | true | tst.js:240:27:240:27 | v |
2 changes: 2 additions & 0 deletions javascript/ql/test/library-tests/TaintBarriers/TaintedSink.expected
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Expand Up @@ -34,3 +34,5 @@
| tst.js:215:14:215:14 | v | tst.js:199:13:199:20 | SOURCE() |
| tst.js:223:14:223:14 | v | tst.js:199:13:199:20 | SOURCE() |
| tst.js:227:14:227:14 | v | tst.js:199:13:199:20 | SOURCE() |
| tst.js:239:14:239:14 | v | tst.js:235:13:235:20 | SOURCE() |
| tst.js:243:14:243:14 | v | tst.js:235:13:235:20 | SOURCE() |
2 changes: 2 additions & 0 deletions javascript/ql/test/library-tests/TaintBarriers/isBarrier.expected
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Expand Up @@ -29,3 +29,5 @@
| tst.js:217:14:217:14 | v | ExampleConfiguration |
| tst.js:221:14:221:14 | v | ExampleConfiguration |
| tst.js:229:14:229:14 | v | ExampleConfiguration |
| tst.js:237:14:237:14 | v | ExampleConfiguration |
| tst.js:241:14:241:14 | v | ExampleConfiguration |
13 changes: 13 additions & 0 deletions javascript/ql/test/library-tests/TaintBarriers/tst.js
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Expand Up @@ -230,3 +230,16 @@ function RelationalIndexOfCheckSanitizer () {
}

}

function adhocWhitelisting() {
var v = SOURCE();
if (isWhitelisted(v))
SINK(v);
else
SINK(v);
if (config.allowValue(v))
SINK(v);
else
SINK(v);

}