The method returns inconsistent expected results after running it about 10,000 times #108811
Description
Description
I use fixed parameters to loop the test. After running about 10,000 times, the returned decryptedByteCount will change from 9 to 1. This happens widely on multiple net8 versions of Linux and Windows.
the code should use release to build. If it is debug mode, this bug cannot be reproduced.
Does this seem to be related to the JIT not optimizing correctly?
public int Decrypt(byte[] buffer, string key, string iv, out byte[] decryptedData)
{
int decryptedByteCount = 0;
decryptedData = new byte[buffer.Length];
using var aes = Aes.Create();
aes.Mode = CipherMode.CBC;
aes.KeySize = 16;
aes.Padding = PaddingMode.Zeros;
var instPwdArray = Encoding.ASCII.GetBytes(key);
var instSaltArray = Encoding.ASCII.GetBytes(iv);
using (var decryptor = aes.CreateDecryptor(instPwdArray, instSaltArray))
{
using (var memoryStream = new MemoryStream(buffer))
{
using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
{
int read;
do
{
read = cryptoStream.Read(
decryptedData,
decryptedByteCount,
decryptedData.Length - decryptedByteCount);
decryptedByteCount += read;
} while (read != 0);
}
}
}
// Found the accurate length of decrypted data
while (decryptedData[decryptedByteCount - 1] == 0 && decryptedByteCount > 0)
{
decryptedByteCount--;
}
return decryptedByteCount;
}
test parameters
var hex = "3AE46205A50ED00E7612A91692552B7A";
var key = "abcdef1234567890";
var iv = "abcdef1234567890";
Decrypt(convert_hex_to_bytes(hex),key,iv, out decrptorBytes)
If I modify the code to the following two methods, this problem can be fixed.
method1: using(){} struct for aes
......
using (var aes = Aes.Create())
{
aes.Mode = CipherMode.CBC;
......
}
while (decryptedData[decryptedByteCount - 1] == 0 && decryptedByteCount > 0)
......
method2: add MemoryBarrier.
......
Thread.MemoryBarrier();
while (decryptedData[decryptedByteCount - 1] == 0 && decryptedByteCount > 0)
......
Reproduction Steps
Repeat the run more than 10,000 times.
Expected behavior
The results should always be consistent.
Actual behavior
After running it about 10,000 times, it will always return wrong results.
Regression?
has never happened on net6.
Known Workarounds
No response
Configuration
No response
Other information
No response