Remember that if you patched a binary with bsdiff, the binary may not be executable after the patch. Which will apply the patch filename.bsdiff to filename. This can be done by moving filename.bsdiff to where filename is to be found (usually indicated in the patches section of every crack) and then issuing:īspatch filename filename filename.bsdiff Uudecode -o filename.bsdiff < Īt which point you will have obtained the filename.bsdiff file. The first column (blue numbers) represents the instructions addresses, then the instruction mnemonic and its operands. This can be performed in a terminal by issuing: ![]() This creates the storage area for the local variables. Hopper Disassembler 2.8.7 let you disassemble any binary you want, and provide you all the information about its content, like imported symbols, or the control flow graph. The CPU will access the memory address to retrieve the machine language instructions that make up the compiled program. These bytes of memory can be accessed by going to its memory address. Memory can be seen as a row of bytes that all have their own memory address. In order to patch filename, you will first have to decode in order to obtain the filename.bsdiff. In the disassembly view of a function, you will normally see it move the stack pointer. The hex numbers on the left, starting with 0x4004f4 are the memory addresses. The uue extension indicating an universal encoded file (using uuencode), and: For example, the patch for filename would be pasted in a file called: Patches are named in this namespace conventionally and you will need to copy & paste the gibberish text in files before applying them. In case you have access and assuming you have Homebrew install, issue in a terminal: Most of the cracks presented here are for OSX and you will need either MacPorts or Homebrew to apply the patches. We can NOP the CMP as well, if we want to be tidy, but it is not needed.īsdiff can be used to create and apply binary patches. Xor cl, cl read (exchange) cmp rax, rbx compare nop no more jumping nop mov cl, 0x1 continue. īy substituting the jump using some NOPs (no operation): ![]() ![]() Xor cl, cl read (exchange) cmp rax, rbx compare jle 0x10001FF07 jump mov cl, 0x1 continue. The most obvious, given the top-down flow of execution, is to get rid of the jump ( jle): MEMORYBASICINFORMATION must be defined this way: C. There are many ways to eliminate the jump in assembler. Basically, this method tells us the range of a memory chunk that starts from the specified address: in order to get to the next memory chunk, we add the length of this region to the current memory address (sum). It does not matter whether reg holds the value 1 or not because the program will never return: Int reg = isRegistered ( ) // read if (reg != 1 ) Better illustrated, let's take the code from the flow-chart above: Manipulating if-branches consists in negating either of the branches in order to favour in outcome.
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