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Fixed the issue with one of the wychproof test vectors for RSA OAEP#117

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Merged
subrahmanyaman merged 1 commit into from
Nov 22, 2022
Merged

Fixed the issue with one of the wychproof test vectors for RSA OAEP #117

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32 changes: 17 additions & 15 deletions Applet/AndroidSEProviderLib/src/com/android/javacard/seprovider/KMRsaOAEPEncoding.java
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Original file line numberDiff line numberDiff line change
Expand Up@@ -125,10 +125,8 @@ public short doFinal(byte[] inBuff, short inOffset, short inLength,
if (len != 256 || outBuff[0] != 0) {
CryptoException.throwIt(CryptoException.ILLEGAL_VALUE);
}
inBuff = outBuff;
inOffset = (short) (outOffset + 1);
return rsaOAEPDecode(inBuff, inOffset, (short) (len - 1), outBuff,
outOffset);
Util.arrayCopyNonAtomic(outBuff, (short) (outOffset + 1), outBuff, (short) 0, (short) (len -1));
return rsaOAEPDecode(outBuff, (short) 0, (short) (len - 1));

}

Expand DownExpand Up@@ -177,7 +175,7 @@ private void I2OS(short i, byte[] out, short offset) {
}

private short rsaOAEPDecode(byte[] encodedMsg, short encodedMsgOff,
short encodedMsgLen, byte[] msg, short offset) {
short encodedMsgLen) {
MessageDigest.OneShot md = null;
byte[] tmpArray = KMAndroidSEProvider.getInstance().tmpArray;

Expand DownExpand Up@@ -232,22 +230,26 @@ private short rsaOAEPDecode(byte[] encodedMsg, short encodedMsgOff,
// encoding parameters is calculated and then copied from the
// starting of the block and a variable length of 0's are
// appended to the end of the hash till the 0x01 byte.
short start = 0;
short start = (short) (encodedMsgOff + encodedMsgLen);
for (short i = (short) (encodedMsgOff + 2 * hLen);
i < (short) (encodedMsgOff + encodedMsgLen); i++) {
if (i == (short) ((encodedMsgOff + encodedMsgLen) - 1)) {
// Bad Padding.
CryptoException.throwIt(CryptoException.ILLEGAL_VALUE);
}
if (encodedMsg[i] != 0) {
if ((encodedMsg[i] != 0)) {
start = i;
break;
}
}
// Copy the message
Util.arrayCopyNonAtomic(encodedMsg, (short) (start + 1), msg, offset,
(short) (encodedMsgLen - ((start - encodedMsgOff) + 1)));
return (short) (encodedMsgLen - ((start - encodedMsgOff) + 1));
if ((start >= (short)(encodedMsgOff + encodedMsgLen)) ||
(encodedMsg[start] != 0x01)) {
// Bad Padding.
CryptoException.throwIt(CryptoException.ILLEGAL_VALUE);
}
start++; // Message starting pos.
if (start < (short)(encodedMsgOff + encodedMsgLen)) {
// Copy the message
Util.arrayCopyNonAtomic(encodedMsg, start, encodedMsg, encodedMsgOff,
(short) (encodedMsgLen - (start - encodedMsgOff)));
}
return (short) (encodedMsgLen - (start - encodedMsgOff));

} finally {
if (md != null) {
Expand Down