If for example a BIOS decides to use all CPU cycles for a very long time, no operating system or application can provide any latency guarantees. The whole system needs to be tuned and configured correctly. The goal is to reduce random latency. This document is divided into for sections which explain how you can reduce latencies if possibe.
A good real time behaviour of a system depends a lot on low latency interrupt handling. Taking a look at the x86 platform, it shows that this platform is not optimised for RT usage. Several mechanisms cause ISR latencies that can run into the 10's or 's of microseconds.
Knowing them will enable you to make the best design choices on this platform to enable you to work around the negative impact. System Management Interrupts are being generated by the power management hardware on the board. SMI's are evil if real-time is required. First off, they can last for hundreds of microseconds, which for many RT applications causes unacceptable jitter.
Second, they are the highest priority interrupt in the system even higher than the NMI. Bus mastering events can cause long-latency CPU stalls of many microseconds. Also video cards that insert wait cycles on the bus in response to a CPU access can cause this kind of latency. Sometimes the behaviour of such peripherals can be controlled from the driver, trading off throughput for lower latency.
The negative impact of bus mastering is independent from the chosen OS, so this is not a unique problem for Linux-RT, even other RTOS-es experience these type of latency! Many BIOS support power management for different hardware types. Obviously, enabling power management saves a few watts on the expensive of latency. Therefore, it is recommended to disable power management options or benchmark the performance of the whole system carefully for each options and their impact on latency.
Hyper threading and also out of order execution of CPUs introduces 'random' latencies. As mentioned in power management, it is recommended to disable these feature if possible or carefully benchmark the performance. The latency will raise to us if you do so. Connecting and using the USB stick later does no harm, however. Creates long-latency events when the CPU is put in a low-power-consumption state after a period of inactivity. Such problems are usually quite easy to detect.
When I talk about unpacking Safengine Shielden whit my friends in Chinese crack forum 52pojie,Nooby come and give us this demo. Safengine Shielden is a free Protection. I think it is a delicious food for you. Don't mis it! Ok so today I also unpacked the NetLicensor protection which does differ from the other SE protections but after some tracings and checkings I found the right places and unpacked this too.
All in all both protections are almost the same and none of them is harder or easier to unpack. In this SL File,Nooby did not use api hash table,so all api will get real address at one place.
Maybe CreateThread is an excetion. I only get api real address,but a big problem comes whitch is I can't get iat type call [dword];jmp [dword] ;call xxxx xxxx:jmp [dword] and mov reg,[xxxx] call reg. I believe you have analysed all vm code but if you have some useful technique to find iat tpye could you tell me about it. First I have again to say that I am always trying to find easy and simple solutions if possible so thats my first step. Also this problem you can find out very simple without to trace into the VM.
Now there are 2 possible ways what should comes next. So all in all its almost pretty simple to find and use the easiest way to handle this problems and for this you can also write a small script which just runs a few minutes to fix all SE calls to the right API commands and addresses of the IAT. Also set the esp address same before you enter a SE call to prevent a stack overflow etc.
One info Thats all what I can say about this protection to handle it on a easy way. So I hope that you can follow my descriptions to unpack the target also by yourself. I have try this way sometimes before i asked you,but it crashed. I find an address at BE, this position se translate real api to shadow api and patch it so all api is real address.
I jmp the store code. LCF-AT,you is an enthusiastic and powerful man! Hi L4Nce. Just only a info of course for you my fan. So as you can see its not so hard to handle this protection so far right.
PS: Nice work and keep going L4Nce. Its already two years ago. You have to trace them. Also you can set BPs on export table datas of dlls like kernel. Now trace and check what the protector does and you will find this address where you get the API address in register. Just check this out again. If you got it then set it back to 0 and now you can call the same call again. I sent you a PM in a sample in which it is impossible to recover the import, look and tell me what is the reason?
Its checking and getting the datas from the tables. From here you can trace forward and check what it does. I made short steplist for that file.. Thats all so far how you can find the address where you see the API raw. If you found then find the right checks where you can bypass the loops to prevent endless tracings. Cant create a separate topic on the patch hwid and unpack this unpackme Safengine Liconsor 2.
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Sign in here. Followers 0. Prev 1 2 Next Page 1 of 2. So it's really the same file and proven that signature information is available in Windows catalogs at all. According to MSDN , might be the following:. Any idea what the not active service might be in the context of a restricted, non-interactive user and the called enumeration function? Any other idea about the root cause of this problem? Attachments: Up to 10 attachments including images can be used with a maximum of 3.
Thanks for your post! According to your description, it seems the issue is code and development related, since Windows-server forum is mainly related to Windows Server system troubleshooting and management, development is out of our scope, so, it's recommended to turn to development-related forum for better help.
Thanks for your understanding! If the Answer is helpful, please click " Accept Answer " and upvote it. Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread. I tried to asked in MS dev-forums and things resulted here, because the other forums have been archived. So which should I use instead? After consultation, the issue is related to the tag "windows-api-general", I added the tag for you.
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