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artem-smotrakovartem-smotrakov
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Better taint propagation in UnsafeTypeConfig
1 parent 476843a commit c98f1a4

3 files changed

Lines changed: 57 additions & 10 deletions

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‎java/ql/src/semmle/code/java/security/UnsafeDeserialization.qll‎

Lines changed: 37 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -10,6 +10,7 @@ import semmle.code.java.frameworks.YamlBeans
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import semmle.code.java.frameworks.HessianBurlap
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import semmle.code.java.frameworks.Castor
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import semmle.code.java.frameworks.apache.Lang
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import semmle.code.java.Reflection
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class ObjectInputStreamReadObjectMethod extends Method {
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ObjectInputStreamReadObjectMethod() {
@@ -246,21 +247,47 @@ private class UnsafeTypeConfig extends TaintTracking2::Configuration {
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}
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/**
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* Holds if `fromNode` to `toNode` is a dataflow step that looks like resolving a class.
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*
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* Note any method that returns a `Class` or similar is assumed to propagate taint from all
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* of its arguments, so methods that accept user-controlled data but sanitize it or use it for some
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* completely different purpose before returning a `Class` could result in false positives.
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* Holds if `fromNode` to `toNode` is a dataflow step that resolves a class
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* or at least looks like resolving a class.
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*/
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override predicate isAdditionalTaintStep(DataFlow::Node fromNode, DataFlow::Node toNode) {
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exists(MethodAccess ma, RefType returnType | returnType = ma.getMethod().getReturnType() |
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returnType instanceof JacksonTypeDescriptorType and
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ma.getAnArgument() = fromNode.asExpr() and
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ma = toNode.asExpr()
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)
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resolveClassStep(fromNode, toNode) or
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looksLikeResolveClassStep(fromNode, toNode)
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}
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}
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/**
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* Holds if `fromNode` to `toNode` is a dataflow step that resolves a class.
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*/
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private predicate resolveClassStep(DataFlow::Node fromNode, DataFlow::Node toNode) {
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exists(ReflectiveClassIdentifierMethodAccess ma |
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ma.getArgument(0) = fromNode.asExpr() and
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ma = toNode.asExpr()
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)
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}
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/**
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* Holds if `fromNode` to `toNode` is a dataflow step that looks like resolving a class.
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* A method probably resolves a class if it is external, takes a string, returns a type descriptor
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* and its name contains "resolve", "load", etc.
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*
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* Any method call that satisfies the rule above is assumed to propagate taint from its string arguments,
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* so methods that accept user-controlled data but sanitize it or use it for some
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* completely different purpose before returning a type descriptor could result in false positives.
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*/
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private predicate looksLikeResolveClassStep(DataFlow::Node fromNode, DataFlow::Node toNode) {
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exists(MethodAccess ma, Method m, int i, Expr arg |
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m = ma.getMethod() and arg = ma.getArgument(i)
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|
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m.getReturnType() instanceof JacksonTypeDescriptorType and
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m.getName().toLowerCase().regexpMatch("resolve|load|class|type") and
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m.fromSource() and
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arg.getType() instanceof TypeString and
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arg = fromNode.asExpr() and
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ma = toNode.asExpr()
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)
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}
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/**
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* Holds if `fromNode` to `toNode` is a dataflow step that creates a Jackson parser.
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*

‎java/ql/test/query-tests/security/CWE-502/JacksonTest.java‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -171,6 +171,21 @@ private static void testUnsafeDeserializationWithUnsafeClass() throws Exception
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mapper.readValue(data, clazz);
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});
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}
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// BAD: an attacker can control both data and type of deserialized object
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private static void testUnsafeDeserializationWithUnsafeClassAndCustomTypeResolver() throws Exception {
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JacksonTest.withSocket(input -> {
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String[] parts = input.split(";");
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String data = parts[0];
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String type = parts[1];
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ObjectMapper mapper = new ObjectMapper();
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mapper.readValue(data, resolveTypeImpl(type));
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});
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}
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private static Class resolveTypeImpl(String type) throws Exception {
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return Class.forName(type);
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}
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}
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class SaferCatDeserialization {

‎java/ql/test/query-tests/security/CWE-502/UnsafeDeserialization.expected‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -89,13 +89,15 @@ edges
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| JacksonTest.java:21:28:21:35 | jexlExpr : String | JacksonTest.java:147:32:147:37 | string : String |
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| JacksonTest.java:21:28:21:35 | jexlExpr : String | JacksonTest.java:156:32:156:37 | string : String |
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| JacksonTest.java:21:28:21:35 | jexlExpr : String | JacksonTest.java:165:32:165:36 | input : String |
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| JacksonTest.java:21:28:21:35 | jexlExpr : String | JacksonTest.java:177:32:177:36 | input : String |
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| JacksonTest.java:73:32:73:37 | string : String | JacksonTest.java:75:30:75:35 | string |
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| JacksonTest.java:82:32:82:37 | string : String | JacksonTest.java:84:30:84:35 | string |
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| JacksonTest.java:91:32:91:37 | string : String | JacksonTest.java:93:30:93:35 | string |
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| JacksonTest.java:138:32:138:37 | string : String | JacksonTest.java:141:30:141:35 | string |
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| JacksonTest.java:147:32:147:37 | string : String | JacksonTest.java:150:31:150:68 | createParser(...) |
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| JacksonTest.java:156:32:156:37 | string : String | JacksonTest.java:159:32:159:54 | readTree(...) |
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| JacksonTest.java:165:32:165:36 | input : String | JacksonTest.java:171:30:171:33 | data |
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| JacksonTest.java:177:32:177:36 | input : String | JacksonTest.java:182:30:182:33 | data |
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| TestMessageBodyReader.java:20:55:20:78 | entityStream : InputStream | TestMessageBodyReader.java:22:18:22:52 | new ObjectInputStream(...) |
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| TestMessageBodyReader.java:20:55:20:78 | entityStream : InputStream | TestMessageBodyReader.java:22:40:22:51 | entityStream : InputStream |
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| TestMessageBodyReader.java:22:40:22:51 | entityStream : InputStream | TestMessageBodyReader.java:22:18:22:52 | new ObjectInputStream(...) |
@@ -209,6 +211,8 @@ nodes
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| JacksonTest.java:159:32:159:54 | readTree(...) | semmle.label | readTree(...) |
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| JacksonTest.java:165:32:165:36 | input : String | semmle.label | input : String |
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| JacksonTest.java:171:30:171:33 | data | semmle.label | data |
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| JacksonTest.java:177:32:177:36 | input : String | semmle.label | input : String |
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| JacksonTest.java:182:30:182:33 | data | semmle.label | data |
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| TestMessageBodyReader.java:20:55:20:78 | entityStream : InputStream | semmle.label | entityStream : InputStream |
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| TestMessageBodyReader.java:22:18:22:52 | new ObjectInputStream(...) | semmle.label | new ObjectInputStream(...) |
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| TestMessageBodyReader.java:22:40:22:51 | entityStream : InputStream | semmle.label | entityStream : InputStream |
@@ -266,4 +270,5 @@ nodes
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| JacksonTest.java:150:13:150:80 | readValues(...) | JacksonTest.java:19:25:19:47 | getInputStream(...) : InputStream | JacksonTest.java:150:31:150:68 | createParser(...) | Unsafe deserialization of $@. | JacksonTest.java:19:25:19:47 | getInputStream(...) | user input |
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| JacksonTest.java:159:13:159:66 | treeToValue(...) | JacksonTest.java:19:25:19:47 | getInputStream(...) : InputStream | JacksonTest.java:159:32:159:54 | readTree(...) | Unsafe deserialization of $@. | JacksonTest.java:19:25:19:47 | getInputStream(...) | user input |
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| JacksonTest.java:171:13:171:41 | readValue(...) | JacksonTest.java:19:25:19:47 | getInputStream(...) : InputStream | JacksonTest.java:171:30:171:33 | data | Unsafe deserialization of $@. | JacksonTest.java:19:25:19:47 | getInputStream(...) | user input |
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| JacksonTest.java:182:13:182:57 | readValue(...) | JacksonTest.java:19:25:19:47 | getInputStream(...) : InputStream | JacksonTest.java:182:30:182:33 | data | Unsafe deserialization of $@. | JacksonTest.java:19:25:19:47 | getInputStream(...) | user input |
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| TestMessageBodyReader.java:22:18:22:65 | readObject(...) | TestMessageBodyReader.java:20:55:20:78 | entityStream : InputStream | TestMessageBodyReader.java:22:18:22:52 | new ObjectInputStream(...) | Unsafe deserialization of $@. | TestMessageBodyReader.java:20:55:20:78 | entityStream | user input |

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