Crypto: OpenSSL ellipitic curve algorithm instances and consumers.

Author: bdrodes

cpp/ql/lib/experimental/quantum/OpenSSL/AlgorithmInstances/EllipticCurveAlgorithmInstance.qll

@@ -0,0 +1,45 @@
+import cpp
+import experimental.quantum.Language
+import KnownAlgorithmConstants
+import OpenSSLAlgorithmInstanceBase
+import AlgToAVCFlow
+
+//ellipticCurveNameToKeySizeAndFamilyMapping(name, size, family)
+class KnownOpenSSLEllitpicCurveConstantAlgorithmInstance extends OpenSSLAlgorithmInstance,
+  Crypto::EllipticCurveInstance instanceof KnownOpenSSLEllipticCurveAlgorithmConstant
+{
+  OpenSSLAlgorithmValueConsumer getterCall;
+
+  KnownOpenSSLEllitpicCurveConstantAlgorithmInstance() {
+    // Two possibilities:
+    // 1) The source is a literal and flows to a getter, then we know we have an instance
+    // 2) The source is a KnownOpenSSLAlgorithm is call, and we know we have an instance immediately from that
+    // Possibility 1:
+    this instanceof Literal and
+    exists(DataFlow::Node src, DataFlow::Node sink |
+      // Sink is an argument to a CipherGetterCall
+      sink = getterCall.(OpenSSLAlgorithmValueConsumer).getInputNode() and
+      // Source is `this`
+      src.asExpr() = this and
+      // This traces to a getter
+      KnownOpenSSLAlgorithmToAlgorithmValueConsumerFlow::flow(src, sink)
+    )
+    or
+    // Possibility 2:
+    this instanceof DirectAlgorithmValueConsumer and getterCall = this
+  }
+
+  override OpenSSLAlgorithmValueConsumer getAVC() { result = getterCall }
+
+  override string getRawEllipticCurveName() { result = this.(Literal).getValue().toString() }
+
+  override Crypto::TEllipticCurveType getEllipticCurveType() {
+    Crypto::ellipticCurveNameToKeySizeAndFamilyMapping(this.(KnownOpenSSLEllipticCurveAlgorithmConstant)
+          .getNormalizedName(), _, result)
+  }
+
+  override int getKeySize() {
+    Crypto::ellipticCurveNameToKeySizeAndFamilyMapping(this.(KnownOpenSSLEllipticCurveAlgorithmConstant)
+          .getNormalizedName(), result, _)
+  }
+}

cpp/ql/lib/experimental/quantum/OpenSSL/AlgorithmInstances/KnownAlgorithmConstants.qll

@@ -67,6 +67,15 @@ class KnownOpenSSLHashAlgorithmConstant extends KnownOpenSSLAlgorithmConstant {
   }
 }
 
+class KnownOpenSSLEllipticCurveAlgorithmConstant extends KnownOpenSSLAlgorithmConstant {
+  string algType;
+
+  KnownOpenSSLEllipticCurveAlgorithmConstant() {
+    resolveAlgorithmFromExpr(this, _, algType) and
+    algType.toLowerCase().matches("elliptic_curve")
+  }
+}
+
 /**
  * Resolves a call to a 'direct algorithm getter', e.g., EVP_MD5()
  * This approach to fetching algorithms was used in OpenSSL 1.0.2.

cpp/ql/lib/experimental/quantum/OpenSSL/AlgorithmInstances/OpenSSLAlgorithmInstances.qll

@@ -3,3 +3,4 @@ import CipherAlgorithmInstance
 import PaddingAlgorithmInstance
 import BlockAlgorithmInstance
 import HashAlgorithmInstance
+import EllipticCurveAlgorithmInstance

cpp/ql/lib/experimental/quantum/OpenSSL/AlgorithmValueConsumers/EllipticCurveAlgorithmValueConsumer.qll

@@ -0,0 +1,35 @@
+import cpp
+import experimental.quantum.Language
+import experimental.quantum.OpenSSL.AlgorithmInstances.KnownAlgorithmConstants
+import experimental.quantum.OpenSSL.AlgorithmValueConsumers.OpenSSLAlgorithmValueConsumerBase
+import experimental.quantum.OpenSSL.AlgorithmInstances.OpenSSLAlgorithmInstances
+
+abstract class EllipticCurveValueConsumer extends OpenSSLAlgorithmValueConsumer { }
+
+//https://docs.openssl.org/3.0/man3/EC_KEY_new/#name
+class EVPEllipticCurveALgorithmConsumer extends EllipticCurveValueConsumer {
+  DataFlow::Node valueArgNode;
+  DataFlow::Node resultNode;
+
+  EVPEllipticCurveALgorithmConsumer() {
+    resultNode.asExpr() = this.(Call) and // in all cases the result is the return
+    isPossibleOpenSSLFunction(this.(Call).getTarget()) and
+    (
+      this.(Call).getTarget().getName() in ["EVP_EC_gen", "EC_KEY_new_by_curve_name"] and
+      valueArgNode.asExpr() = this.(Call).getArgument(0)
+      or
+      this.(Call).getTarget().getName() in [
+          "EC_KEY_new_by_curve_name_ex", "EVP_PKEY_CTX_set_ec_paramgen_curve_nid"
+        ] and
+      valueArgNode.asExpr() = this.(Call).getArgument(2)
+    )
+  }
+
+  override Crypto::AlgorithmInstance getAKnownAlgorithmSource() {
+    exists(OpenSSLAlgorithmInstance i | i.getAVC() = this and result = i)
+  }
+
+  override DataFlow::Node getResultNode() { result = resultNode }
+
+  override Crypto::ConsumerInputDataFlowNode getInputNode() { result = valueArgNode }
+}

cpp/ql/lib/experimental/quantum/OpenSSL/AlgorithmValueConsumers/OpenSSLAlgorithmValueConsumers.qll

@@ -3,3 +3,4 @@ import CipherAlgorithmValueConsumer
 import DirectAlgorithmValueConsumer
 import PaddingAlgorithmValueConsumer
 import HashAlgorithmValueConsumer
+import EllipticCurveAlgorithmValueConsumer