Memory corruption detection tool

You can find erratic programming and memory-access errors, such as heap corruption, rogue threads, memory leaks, array out of bounds, and invalid pointers.

The first and most detailed analysis is achieved with full source-code instrumentation. Software developers get a graphical view of live data about ongoing memory usage and memory allocations over time with specific visibility into overall heap usage, block allocations, possible outstanding leaks, and so on. If a block has been leaked, you can see the allocation stack trace, as well as the stack trace where the leak occurred. The overall size of the heap is monitored, and various statistics are tracked like the number of allocation and deallocation calls.

The detailed information you get includes the type of bug, source file and line number, actual source code line contents, expression that caused the problem, and information about all pointers and memory blocks involved in the bug.

Software developers can also see pointer values, memory blocks pointed to, block allocation information, and the stack trace showing how the program got to the bug location. Most projects are large and contain multiple files. Nevertheless, there are times when you will need to investigate only a handful of those files for suspected runtime violations. The individual files can then get linked to a non-instrumented executable. This finds errors in the files in question at the source level with minimum effort.

With an increased awareness that security is no longer an optional consideration, it is critical to ensure that your applications are secure at the core. With built-in coverage analysis and dynamic memory visualization, you can find areas of the code that need to be exercised to check for errors and locate causes of heap fragmentation.

Memory corruption. Check out this list , and this SO question. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Are there a free Heap corruption detection tools for windows? Asked 10 years, 9 months ago.

Active 10 years ago. Viewed 7k times. Now, what are the consequences of invalid memory access? Actually, there may happen several things:. If this memory was read, it may contain anything i. If what was read is not going to affect your behavior, there's almost no problem.

However if the read value is important, from now on, your program depends on some random junk. If this memory was written, it is much worse, because you've just smashed someone's data, and you have no clue who was that.

This damage is irreversible , and the program may crash or do something stupid any time. Finding invalid memory access is a big challenge. Mostly, this is because the first situation where you have an immediate crash is pretty rare. Usually, the effect of memory corruption is not seen until the corrupted memory is eventually used. Since this is a known problem, there're standard memory corruption detection methods.

All those heap corruption methods work the same way: when you allocate a memory block, they internally allocate a bigger block, and surround the region allocated for you by some values.

Then, when you free this memory, they verify that the decoration is not damaged. This method is good to indicate a problem; however, it's not really helpful in finding it. You only see that the memory is corrupted when you try to release it, but you have no clue who is the violator and when and how the crime could happen.

Plus, you don't have an indication for invalid memory reads. Though not so much destructive, those must be found and fixed too.

This method implements heap in such a way that invalid memory access is guaranteed to result in an access violation. Hence, the goal is achieved. The rest - realizing and fixing the problem - is up to you.

Every returned memory address is padded so that there's an exact number of bytes that may be accessed; attempt to read one extra byte leads to access violation. The allocation may be done in two modes: one guarantees an access violation when you attempt to access memory after the permitted region, and the other mode - access violation when you attempt to access memory before the permitted region.

The accessible page is marked by green, and the inaccessible page is marked by cyan; the allocated memory block pointer to which is returned is marked by blue. As you can see, for every memory allocation, no matter how small it is, we reserve at least two memory pages in the address space.

All of them except one are allocated, and the return address is padded appropriately. Furthermore, when you free the memory via our heap - it deal locates all the memory pages, but it does not immediately free them. Instead, it leaves them in the reserved state. In this state, they're inaccessible and they don't consume physical memory, and they're guaranteed not to become allocated eventually, hence they definitely will remain inaccessible.

When the virtual size occupied by those reserved pages exceeds some number which is 50MB by default , the heap starts to release the most recent pages.

Well, needless to say, this method wastes memory both physical memory and the address space in an extremely barbaric way. And, it may not be used in the applications shipped to the user. However, it's an excellent tool for finding invalid memory accesses at debug time. To enable it, put the following code lines:. You may get a linker error, but with some manipulation, you may get rid of it.

And, using advanced hacking techniques such as Richter's method for intercepting DLL calls , you may even try to hack all the heap functions in the process. Well, I believe this method is awesome.

Looking for the cause of the memory corruption is a real pain in the neck, sometimes it's just a nightmare. And, this method proved at least for me to be very useful. You may try to use this method and see how wonderfully your program crashes the moment you try to do something wrong. When the program crashes exactly at the moment of the invalid memory access, this is a miracle!

You should pray for this to happen. Because if it does not, you're screwed. It may take days to reproduce the problem and find its cause. One more thing: if you intent to look at the code level of this method, I recommend reading the following articles:.

Sign in Email. Forgot your password? Search within: Articles Quick Answers Messages. Tagged as VC6. Stats Immediate memory corruption detection. Please Sign up or sign in to vote. Download source code - 13 KB Introduction This article presents a method to detect invalid heap memory accesses in the code. Process memory from the OS point of view The virtual address space of a process consists of memory pages. In-process memory allocation The term allocated memory block refers to the situation where you have a piece of memory that no one is allowed to touch besides you.

There are several types of memory allocations: Global process memory which actually may consist of different things, such as code, data, etc. In particular, all the global variables are stored there. Stack memory. Every thread is given its own stack by the OS. In particular, automatic variables and function parameters are stored there.

Heap memory. It's allocated and freed explicitly by the appropriate functions and operators. Heap allocations give maximum flexibility. However, this flexibility has its price: You are responsible to free all the allocated memory. Otherwise, there'll be memory leaks. Heap allocation is a relatively complex operation.

It's very much heavier than stack allocation, hence it should not be used unless really needed. Heap allocations have significant memory overhead and produce memory fragmentation, unlike other allocation types where all the variables are closely-packed. Invalid memory access The term invalid memory access refers to a situation where some piece of code tries to access i.

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