Add checks for ciphersuite validity vs the negotiated version

1 files changed, 3 insertions, 2 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/tls/TlsClientProtocol.java b/core/src/main/java/org/bouncycastle/crypto/tls/TlsClientProtocol.java
index 5a546618..f339df27 100644
--- a/core/src/main/java/org/bouncycastle/crypto/tls/TlsClientProtocol.java
+++ b/core/src/main/java/org/bouncycastle/crypto/tls/TlsClientProtocol.java
@@ -634,12 +634,13 @@ public class TlsClientProtocol
 
         /*
          * Find out which CipherSuite the server has chosen and check that it was one of the offered
-         * ones.
+         * ones, and is a valid selection for the negotiated version.
          */
         int selectedCipherSuite = TlsUtils.readUint16(buf);
         if (!Arrays.contains(this.offeredCipherSuites, selectedCipherSuite)
             || selectedCipherSuite == CipherSuite.TLS_NULL_WITH_NULL_NULL
-            || selectedCipherSuite == CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV)
+            || selectedCipherSuite == CipherSuite.TLS_EMPTY_RENEGOTIATION_INFO_SCSV
+            || !TlsUtils.isValidCipherSuiteForVersion(selectedCipherSuite, server_version))
         {
             throw new TlsFatalAlert(AlertDescription.illegal_parameter);
         }