Boundary checks improvement: detect when plaintextOffset + length is greater than length #12
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rweather
reviewed
Sep 2, 2020
| @@ -187,7 +187,7 @@ public int encryptWithAd(byte[] ad, byte[] plaintext, int plaintextOffset, | |||
| int space; | |||
| if (ciphertextOffset < 0 || ciphertextOffset > ciphertext.length) | |||
| throw new IllegalArgumentException(); | |||
| if (length < 0 || plaintextOffset < 0 || plaintextOffset > plaintext.length || plaintextOffset + length > plaintext.length) | |||
| if (length < 0 || plaintextOffset < 0 || plaintextOffset > plaintext.length || plaintextOffset + length < plaintextOffset || plaintextOffset + length > plaintext.length) | |||
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A simpler approach may be to use:
|| length > plaintext.length || (plaintext.length - plaintextOffset) < length
This avoids the wrap-around problem with "plaintextOffset + plaintext.length" going negative.
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Nice one, I've implemented your suggestion :)
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This patch completes the previous commit by introducing one missing boundary check.