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JavaScript: Improve StackTraceExposure query. #443

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Merged
semmle-qlci merged 1 commit into from
Nov 12, 2018
Merged

JavaScript: Improve StackTraceExposure query. #443

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1 change: 1 addition & 0 deletions change-notes/1.19/analysis-javascript.md
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@
| Unused import | Fewer false-positive results | This rule no longer flags imports used by the `transform-react-jsx` Babel plugin. |
| Self assignment | Fewer false-positive results | This rule now ignores self-assignments preceded by a JSDoc comment with a `@type` tag. |
| Client side cross-site scripting | More results | This rule now also flags HTML injection in the body of an email. |
| Information exposure through a stack trace | More results | This rule now also flags cases where the entire exception object (including the stack trace) may be exposed. |

## Changes to QL libraries

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22 changes: 16 additions & 6 deletions javascript/ql/src/semmle/javascript/security/dataflow/StackTraceExposure.qll
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Expand Up @@ -23,22 +23,32 @@ module StackTraceExposure {
src instanceof Source
}

override predicate isSanitizer(DataFlow::Node nd) {
super.isSanitizer(nd)
or
// read of a property other than `stack`
nd.(DataFlow::PropRead).getPropertyName() != "stack"
or
// `toString` does not include the stack trace
nd.(DataFlow::MethodCallNode).getMethodName() = "toString"
or
nd = StringConcatenation::getAnOperand(_)
}

override predicate isSink(DataFlow::Node snk) {
snk instanceof Sink
}
}


/**
* A read of the `stack` property of an exception, viewed as a data flow
* sink for stack trace exposure vulnerabilities.
*/
class DefaultSource extends Source, DataFlow::ValueNode {
class DefaultSource extends Source, DataFlow::Node {
DefaultSource() {
// any read of the `stack` property of an exception is a source
exists (Parameter exc |
exc = any(TryStmt try).getACatchClause().getAParameter() and
this = DataFlow::parameterNode(exc).getAPropertyRead("stack")
)
// any exception is a source
this = DataFlow::parameterNode(any(TryStmt try).getACatchClause().getAParameter())
}
}

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4 changes: 3 additions & 1 deletion javascript/ql/test/query-tests/Security/CWE-209/StackTraceExposure.expected
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@@ -1 +1,3 @@
| node.js:11:13:11:21 | err.stack | Stack trace information from $@ may be exposed to an external user here. | node.js:11:13:11:21 | err.stack | here |
| node.js:11:13:11:21 | err.stack | Stack trace information from $@ may be exposed to an external user here. | node.js:8:10:8:12 | err | here |
| tst.js:7:13:7:13 | e | Stack trace information from $@ may be exposed to an external user here. | tst.js:6:12:6:12 | e | here |
| tst.js:17:11:17:17 | e.stack | Stack trace information from $@ may be exposed to an external user here. | tst.js:6:12:6:12 | e | here |
18 changes: 18 additions & 0 deletions javascript/ql/test/query-tests/Security/CWE-209/tst.js
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@@ -0,0 +1,18 @@
var http = require('http');

http.createServer(function onRequest(req, res) {
try {
throw new Error();
} catch (e) {
res.end(e); // NOT OK
fail(res, e);
res.end(e.message); // OK
res.end("Caught exception " + e); // OK
res.end(e.toString()); // OK
res.end(`Caught exception ${e}.`); // OK
}
});

function fail(res, e) {
res.end(e.stack); // NOT OK
}