Panic within QUICRandomFrames #49
Description
Hey,
This is a great library, however there seems to be an issue with the QUICRandomFrames algorithm I am sometimes running into. It throws: panic: crypto/rand: argument to Int is <= 0
Based on the stacktrace it occurs at this line:
Line 253 in 98f5a5d
I modified the surrounding code blindly to avoid overflows:
lenCryptoData := uint64(len(cryptoData))
offsetCryptoData := uint64(0)
for i := uint64(0); i < numCRYPTO-1; i++ { // select n-1 times, since the last one must be the remaining
// randomly select length of CRYPTO frame.
// Length must be at least 1 byte and at most the remaining length of cryptoData minus the remaining number of CRYPTO frames.
// i.e. len in [1, len(cryptoData)-offsetCryptoData-(numCRYPTO-i-2))
log.Printf("lenCryptoData: %d, offsetCryptoData: %d, numCRYPTO: %d, i: %d\n", lenCryptoData, offsetCryptoData, numCRYPTO, i)
remainingCrypto := lenCryptoData - (numCRYPTO - i - 2)
// check if it overflows uint64
if remainingCrypto > 0xFFFFFFFF || remainingCrypto == 0 {
log.Printf("remainingCrypto overflow: %d\n", remainingCrypto)
break
} else {
log.Printf("remainingCrypto: %d\n", remainingCrypto)
}
lenCRYPTO, err := cryptoSafeRandUint64(1, remainingCrypto)
if err != nil {
return nil, err
}
frameList = append(frameList, QUICFrameCrypto{Offset: int(offsetCryptoData), Length: int(lenCRYPTO)})
offsetCryptoData += lenCRYPTO
lenCryptoData -= lenCRYPTO
}And in the problematic case I saw this in the logs:
2024/12/20 03:59:19 lenCryptoData: 508, offsetCryptoData: 0, numCRYPTO: 5, i: 0
2024/12/20 03:59:19 remainingCrypto: 505
2024/12/20 03:59:19 lenCryptoData: 69, offsetCryptoData: 439, numCRYPTO: 5, i: 1
2024/12/20 03:59:19 remainingCrypto: 67
2024/12/20 03:59:19 lenCryptoData: 54, offsetCryptoData: 454, numCRYPTO: 5, i: 2
2024/12/20 03:59:19 remainingCrypto: 53
2024/12/20 03:59:19 lenCryptoData: 31, offsetCryptoData: 477, numCRYPTO: 5, i: 3
2024/12/20 03:59:19 remainingCrypto: 31
2024/12/20 03:59:19 lenCryptoData: 0, offsetCryptoData: 0, numCRYPTO: 6, i: 0
2024/12/20 03:59:19 remainingCrypto overflow: 18446744073709551612
It doesn't always happen, but when it does, the program panics...