codeql/cpp/ql/lib/experimental/Quantum/OpenSSL/OpenSSLAlgorithmGetter.qll

import cpp
import semmle.code.cpp.dataflow.new.DataFlow
import LibraryDetector
import OpenSSLKnownAlgorithmConstants

abstract class AlgorithmPassthroughCall extends Call {
  abstract DataFlow::Node getInNode();

  abstract DataFlow::Node getOutNode();
}

class CopyAndDupAlgorithmPassthroughCall extends AlgorithmPassthroughCall {
  DataFlow::Node inNode;
  DataFlow::Node outNode;

  CopyAndDupAlgorithmPassthroughCall() {
    // Flow out through any return or other argument of the same type
    // Assume flow in and out is asIndirectExpr or asDefinitingArgument since a pointer is assumed
    // to be involved
    // NOTE: not attempting to detect openssl specific copy/dup functions, but anything suspected to be copy/dup
    this.getTarget().getName().toLowerCase().matches(["%_dup", "%_copy"]) and
    exists(Expr inArg, Type t |
      inArg = this.getAnArgument() and t = inArg.getUnspecifiedType().stripType()
    |
      inNode.asIndirectExpr() = inArg and
      (
        // Case 1: flow through another argument as an out arg of the same type
        exists(Expr outArg |
          outArg = this.getAnArgument() and
          outArg != inArg and
          outArg.getUnspecifiedType().stripType() = t
        |
          outNode.asDefiningArgument() = outArg
        )
        or
        // Case 2: flow through the return value if the result is the same as the intput type
        exists(Expr outArg | outArg = this and outArg.getUnspecifiedType().stripType() = t |
          outNode.asIndirectExpr() = outArg
        )
      )
    )
  }

  override DataFlow::Node getInNode() { result = inNode }

  override DataFlow::Node getOutNode() { result = outNode }
}

class NIDToPointerPassthroughCall extends AlgorithmPassthroughCall {
  DataFlow::Node inNode;
  DataFlow::Node outNode;

  NIDToPointerPassthroughCall() {
    this.getTarget().getName() in ["OBJ_nid2obj", "OBJ_nid2ln", "OBJ_nid2sn"] and
    inNode.asExpr() = this.getArgument(0) and
    outNode.asExpr() = this
    //outNode.asIndirectExpr() = this
  }

  override DataFlow::Node getInNode() { result = inNode }

  override DataFlow::Node getOutNode() { result = outNode }
}

class PointerToPointerPassthroughCall extends AlgorithmPassthroughCall {
  DataFlow::Node inNode;
  DataFlow::Node outNode;

  PointerToPointerPassthroughCall() {
    this.getTarget().getName() = "OBJ_txt2obj" and
    inNode.asIndirectExpr() = this.getArgument(0) and
    outNode.asIndirectExpr() = this
    or
    //outNode.asExpr() = this
    this.getTarget().getName() in ["OBJ_obj2txt", "i2t_ASN1_OBJECT"] and
    inNode.asIndirectExpr() = this.getArgument(2) and
    outNode.asDefiningArgument() = this.getArgument(0)
  }

  override DataFlow::Node getInNode() { result = inNode }

  override DataFlow::Node getOutNode() { result = outNode }
}

class PointerToNIDPassthroughCall extends AlgorithmPassthroughCall {
  DataFlow::Node inNode;
  DataFlow::Node outNode;

  PointerToNIDPassthroughCall() {
    this.getTarget().getName() in ["OBJ_obj2nid", "OBJ_ln2nid", "OBJ_sn2nid", "OBJ_txt2nid"] and
    (
      inNode.asIndirectExpr() = this.getArgument(0)
      or
      inNode.asExpr() = this.getArgument(0)
    ) and
    outNode.asExpr() = this
  }

  override DataFlow::Node getInNode() { result = inNode }

  override DataFlow::Node getOutNode() { result = outNode }
}

predicate knownPassThroughStep(DataFlow::Node node1, DataFlow::Node node2) {
  exists(AlgorithmPassthroughCall c | c.getInNode() = node1 and c.getOutNode() = node2)
}

abstract class OpenSSLAlgorithmGetterCall extends Call {
  abstract DataFlow::Node getValueArgNode();

  abstract DataFlow::Node getResultNode();

  abstract Expr getValueArgExpr();

  abstract Expr getResultExpr();
}

module KnownAlgorithmLiteralToAlgorithmGetterConfig implements DataFlow::ConfigSig {
  predicate isSource(DataFlow::Node source) {
    (
      source.asExpr() instanceof Literal and
      // 0 sources, for nid are unknown, and 0 otherwise represents a null assignment (ignore as unknown)
      exists(source.asExpr().(Literal).getValue().toInt()) implies source.asExpr().(Literal).getValue().toInt() != 0
      //resolveAlgorithmFromLiteral(source.asExpr(),_,_)
    )
  }

  predicate isSink(DataFlow::Node sink) {
    exists(OpenSSLAlgorithmGetterCall c | c.getValueArgNode() = sink)
  }

  predicate isBarrier(DataFlow::Node node) {
    // False positive reducer, don't flow out through argv
    exists(VariableAccess va, Variable v |
      v.getAnAccess() = va and va = node.asExpr()
      or
      va = node.asIndirectExpr()
    |
      v.getName().matches("%argv")
    )
  }

  predicate isAdditionalFlowStep(DataFlow::Node node1, DataFlow::Node node2) {
    knownPassThroughStep(node1, node2)
  }
}

module KnownAlgorithmLiteralToAlgorithmGetterFlow =
  DataFlow::Global<KnownAlgorithmLiteralToAlgorithmGetterConfig>;

// https://www.openssl.org/docs/manmaster/man3/EVP_CIPHER_fetch.html
class EVPCipherGetterCall extends OpenSSLAlgorithmGetterCall {
  DataFlow::Node valueArgNode;
  DataFlow::Node resultNode;
  Expr valueArgExpr;
  Expr resultExpr;

  EVPCipherGetterCall() {
    // Flow out through the return pointer itself (trace the pointer, not what it is pointing to)
    resultExpr = this and
    resultNode.asExpr() = this and
    (
      this.getTarget().getName() in ["EVP_get_cipherbyname", "EVP_get_cipherbyobj"] and
      valueArgExpr = this.getArgument(0) and
      valueArgNode.asExpr() = valueArgExpr
      or
      this.getTarget().getName() = "EVP_CIPHER_fetch" and
      valueArgExpr = this.getArgument(1) and
      valueArgNode.asExpr() = valueArgExpr
      or
      this.getTarget().getName() = "EVP_get_cipherbynid" and
      valueArgExpr = this.getArgument(0) and
      valueArgNode.asExpr() = valueArgExpr
    )
  }

  override DataFlow::Node getValueArgNode() { result = valueArgNode }

  override DataFlow::Node getResultNode() { result = resultNode }

  override Expr getValueArgExpr() { result = valueArgExpr }

  override Expr getResultExpr() { result = resultExpr }
}
// /**
//  * Predicates/classes for identifying algorithm sinks.
//  * An Algorithm Sink is a function that takes an algorithm as an argument.
//  * In particular, any function that takes in an algorithm that until the call
//  * the algorithm is not definitely known to be an algorithm (e.g., an integer used as an identifier to fetch an algorithm)
//  */
// //TODO: enforce a hierarchy of AlgorithmSinkArgument, e.g., so I can get all Asymmetric SinkArguments that includes all the strictly RSA etc.
// import cpp
// // import experimental.cryptography.utils.OpenSSL.LibraryFunction
// // import experimental.cryptography.CryptoAlgorithmNames
// predicate isAlgorithmSink(AlgorithmSinkArgument arg, string algType) { arg.algType() = algType }
// abstract class AlgorithmSinkArgument extends Expr {
//   AlgorithmSinkArgument() {
//     exists(Call c | c.getAnArgument() = this and openSSLLibraryFunc(c.getTarget()))
//   }
//   /**
//    * Gets the function call in which the argument exists
//    */
//   Call getSinkCall() { result.getAnArgument() = this }
//   abstract string algType();
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_CIPHER_fetch.html
// predicate cipherAlgorithmSink(string funcName, int argInd) {
//   funcName in ["EVP_get_cipherbyname", "EVP_get_cipherbynid", "EVP_get_cipherbyobj"] and argInd = 0
//   or
//   funcName = "EVP_CIPHER_fetch" and argInd = 1
// }
// class CipherAlgorithmSink extends AlgorithmSinkArgument {
//   CipherAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       cipherAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getSymmetricEncryptionType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_MAC_fetch
// predicate macAlgorithmSink(string funcName, int argInd) {
//   (funcName = "EVP_MAC_fetch" and argInd = 1)
// }
// class MACAlgorithmSink extends AlgorithmSinkArgument {
//   MACAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       macAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = "TBD" }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_MD_fetch
// predicate messageDigestAlgorithmSink(string funcName, int argInd) {
//   funcName in ["EVP_get_digestbyname", "EVP_get_digestbynid", "EVP_get_digestbyobj"] and argInd = 0
//   or
//   funcName = "EVP_MD_fetch" and argInd = 1
// }
// class MessageDigestAlgorithmSink extends AlgorithmSinkArgument {
//   MessageDigestAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       messageDigestAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getHashType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_KEYEXCH_fetch
// // https://www.openssl.org/docs/manmaster/man3/EVP_KEM_fetch
// predicate keyExchangeAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_KEYEXCH_fetch" and argInd = 1
//   or
//   funcName = "EVP_KEM_fetch" and argInd = 1
// }
// class KeyExchangeAlgorithmSink extends AlgorithmSinkArgument {
//   KeyExchangeAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       keyExchangeAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getKeyExchangeType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_KEYMGMT_fetch
// predicate keyManagementAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_KEYMGMT_fetch" and argInd = 1
// }
// class KeyManagementAlgorithmSink extends AlgorithmSinkArgument {
//   KeyManagementAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       keyManagementAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = "TBD" }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_KDF
// predicate keyDerivationAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_KDF_fetch" and argInd = 1
// }
// class KeyDerivationAlgorithmSink extends AlgorithmSinkArgument {
//   KeyDerivationAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       keyDerivationAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getKeyDerivationType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_ASYM_CIPHER_fetch
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_CTX_new_id
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_new_CMAC_key.html
// predicate asymmetricCipherAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_ASYM_CIPHER_fetch" and argInd = 1
//   or
//   funcName = "EVP_PKEY_new_CMAC_key" and argInd = 3
//   // NOTE: other cases are handled by AsymmetricAlgorithmSink
// }
// class AsymmetricCipherAlgorithmSink extends AlgorithmSinkArgument {
//   AsymmetricCipherAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       asymmetricCipherAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = "ASYMMETRIC_ENCRYPTION" }
// }
// class AsymmetricCipherAlgorithmSink_EVP_PKEY_Q_keygen extends AlgorithmSinkArgument {
//   AsymmetricCipherAlgorithmSink_EVP_PKEY_Q_keygen() {
//     exists(Call c, string funcName |
//       funcName = c.getTarget().getName() and
//       this = c.getArgument(3)
//     |
//       funcName = "EVP_PKEY_Q_keygen" and
//       c.getArgument(3).getType().getUnderlyingType() instanceof IntegralType
//     )
//   }
//   override string algType() { result = "ASYMMETRIC_ENCRYPTION" }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_RAND_fetch
// predicate randomAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_RAND_fetch" and argInd = 1
// }
// class RandomAlgorithmSink extends AlgorithmSinkArgument {
//   RandomAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       randomAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = "TBD" }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_SIGNATURE_fetch
// predicate signatureAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_SIGNATURE_fetch" and argInd = 1
// }
// class SignatureAlgorithmSink extends AlgorithmSinkArgument {
//   SignatureAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       signatureAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getSignatureType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EC_KEY_new_by_curve_name.html
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_CTX_set_ec_paramgen_curve_nid.html
// predicate ellipticCurveAlgorithmSink(string funcName, int argInd) {
//   funcName in ["EC_KEY_new_by_curve_name", "EVP_EC_gen"] and argInd = 0
//   or
//   funcName = "EC_KEY_new_by_curve_name_ex" and argInd = 2
//   or
//   funcName in ["EVP_PKEY_CTX_set_ec_paramgen_curve_nid"] and argInd = 1
// }
// class EllipticCurveAlgorithmSink extends AlgorithmSinkArgument {
//   EllipticCurveAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       ellipticCurveAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getEllipticCurveType() }
// }
// /**
//  * Special cased to address the fact that arg index 3 (zero offset based) is the curve name.
//  * ASSUMPTION: if the arg ind 3 is a char* assume it is an elliptic curve
//  */
// class EllipticCurveAlgorithmSink_EVP_PKEY_Q_keygen extends AlgorithmSinkArgument {
//   EllipticCurveAlgorithmSink_EVP_PKEY_Q_keygen() {
//     exists(Call c, string funcName |
//       funcName = c.getTarget().getName() and
//       this = c.getArgument(3)
//     |
//       funcName = "EVP_PKEY_Q_keygen" and
//       c.getArgument(3).getType().getUnderlyingType() instanceof PointerType and
//       c.getArgument(3).getType().getUnderlyingType().stripType() instanceof CharType
//     )
//   }
//   override string algType() { result = getEllipticCurveType() }
// }
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_CTX_new_id.html
// // https://www.openssl.org/docs/man1.1.1/man3/EVP_PKEY_new_raw_private_key.html
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_new.html
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_CTX_ctrl.html
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_Q_keygen.html
// // https://www.openssl.org/docs/manmaster/man3/EVP_PKEY_CTX_ctrl.html
// predicate asymmetricAlgorithmSink(string funcName, int argInd) {
//   funcName = "EVP_PKEY_CTX_new_id" and argInd = 0
//   or
//   funcName = "EVP_PKEY_CTX_new_from_name" and argInd = 1
//   or
//   funcName in [
//       "EVP_PKEY_new_raw_private_key", "EVP_PKEY_new_raw_public_key", "EVP_PKEY_new_mac_key"
//     ] and
//   argInd = 0
//   or
//   funcName in ["EVP_PKEY_new_raw_private_key_ex", "EVP_PKEY_new_raw_public_key_ex"] and argInd = 1
//   or
//   // special casing this as arg index 3 must be specified depending on if RSA or ECC, and otherwise not specified for other algs
//   // funcName = "EVP_PKEY_Q_keygen" and argInd = 2
//   funcName in ["EVP_PKEY_CTX_ctrl", "EVP_PKEY_CTX_set_group_name"] and argInd = 1
//   // TODO consider void cases EVP_PKEY_new
// }
// class AsymmetricAlgorithmSink extends AlgorithmSinkArgument {
//   AsymmetricAlgorithmSink() {
//     exists(Call c, string funcName, int argInd |
//       funcName = c.getTarget().getName() and this = c.getArgument(argInd)
//     |
//       asymmetricAlgorithmSink(funcName, argInd)
//     )
//   }
//   override string algType() { result = getAsymmetricType() }
// }
// class AsymmetricAlgorithmSink_EVP_PKEY_Q_keygen extends AlgorithmSinkArgument {
//   AsymmetricAlgorithmSink_EVP_PKEY_Q_keygen() {
//     exists(Call c, string funcName |
//       funcName = c.getTarget().getName() and
//       this = c.getArgument(2)
//     |
//       funcName = "EVP_PKEY_Q_keygen" and
//       not exists(c.getArgument(3))
//     )
//   }
//   override string algType() { result = getAsymmetricType() }
// }