From 5cb7bed7f82b9907901529ec3f5ede37ad18cfe1 Mon Sep 17 00:00:00 2001
From: "avinash.hedage" <avinash.hedage@quest-global.com>
Date: Tue, 21 Jun 2022 06:34:17 +0000
Subject: [PATCH] handled aes des no pad zero input

---
 .../javacard/keymaster/KMKeymasterApplet.java | 22 +++++++++++++++++--
 .../javacard/keymaster/KMOperationState.java  | 13 +++++++++++
 2 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java b/Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java
index e10e8220..c3339420 100644
--- a/Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java
+++ b/Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java
@@ -1776,7 +1776,19 @@ private void finishAesDesOperation(KMOperationState op){
           KMByteBlob.cast(data[OUTPUT_DATA]).getStartOff());
     } catch (CryptoException e) {
       if (e.getReason() == CryptoException.ILLEGAL_USE) {
-        KMException.throwIt(KMError.INVALID_INPUT_LENGTH);
+        // As per VTS, zero length input on AES/DES with PADDING_NONE Should return a zero length
+        // output. But JavaCard fails with CryptoException.ILLEGAL_USE if no input data is
+        // provided via update() method. So ignore this exception in case if all below conditions
+        // are satisfied and simply return empty output.
+        // 1. padding mode is PADDING_NONE.
+        // 2. No input  message is processed in update().
+        // 3. Zero length input data is passed in finish operation.
+        if ((op.getPadding() == KMType.PADDING_NONE) &&
+          !op.isInputMsgProcessed() && (KMByteBlob.cast(data[INPUT_DATA]).length() == 0)) {
+          len = 0;
+        } else {
+          KMException.throwIt(KMError.INVALID_INPUT_LENGTH);
+        }
       }
     }
     KMByteBlob.cast(data[OUTPUT_DATA]).setLength(len);
@@ -2136,7 +2148,13 @@ private void processUpdateOperationCmd(APDU apdu) {
       } catch (CryptoException e) {
         KMException.throwIt(KMError.INVALID_TAG);
       }
-
+      if (KMByteBlob.cast(data[INPUT_DATA]).length() > 0) {
+        // This flag is used to denote that an input data of length > 0 is received and processed
+        // successfully in update command. This flag is later used in the finish operation
+        // to handle a particular use case, where a zero length input data on AES/DES algorithm
+        // with PADDING_NONE should return a zero length output with OK response.
+        op.setProcessedInputMsg(true);
+      }
       // Adjust the Output data if it is not equal to input data.
       // This happens in case of JCardSim provider.
       KMByteBlob.cast(data[OUTPUT_DATA]).setLength(len);
diff --git a/Applet/src/com/android/javacard/keymaster/KMOperationState.java b/Applet/src/com/android/javacard/keymaster/KMOperationState.java
index a6ed2280..8c9bb545 100644
--- a/Applet/src/com/android/javacard/keymaster/KMOperationState.java
+++ b/Applet/src/com/android/javacard/keymaster/KMOperationState.java
@@ -56,6 +56,7 @@ public class KMOperationState {
   private static final short SECURE_USER_ID_REQD = 2;
   private static final short AUTH_TIMEOUT_VALIDATED = 4;
   private static final short AES_GCM_UPDATE_ALLOWED = 8;
+  private static final byte PROCESSED_INPUT_MSG = 16;
   // Max user secure ids.
   private static final byte MAX_SECURE_USER_IDS = 5;
 
@@ -122,6 +123,10 @@ public void setPurpose(short purpose) {
     data[PURPOSE] = purpose;
   }
 
+  public boolean isInputMsgProcessed() {
+    return (data[FLAGS] & PROCESSED_INPUT_MSG) != 0;
+  }
+
   public void setOperation(KMOperation op) {
     operations[OPERATION] = op;
   }
@@ -150,6 +155,14 @@ public void setAuthTime(byte[] timeBuf, short start) {
     Util.arrayCopyNonAtomic(timeBuf, start, authTime, (short) 0, AUTH_TIME_SIZE);
   }
 
+  public void setProcessedInputMsg(boolean flag) {
+    if (flag) {
+      data[FLAGS] = (byte) (data[FLAGS] | PROCESSED_INPUT_MSG);
+    } else {
+      data[FLAGS] = (byte) (data[FLAGS] & (~PROCESSED_INPUT_MSG));
+    }
+  }
+
   public void setOneTimeAuthReqd(boolean flag) {
     if (flag) {
       data[FLAGS] = (short) (data[FLAGS] | SECURE_USER_ID_REQD);