Contents
What is the frame pointer used for?
The frame pointer ($fp) points to the start of the stack frame and does not move for the duration of the subroutine call. This points to the base of the stack frame, and the parameters that are passed in to the subroutine remain at a constant spot relative to the frame pointer.
Are SP and FP same?
When “SP” comes into picture and when “FP” comes into picture. The SP comes into the picture when you are mainpulating the stack. The FP comes into the picture when you are manipulating the frame.
What register is FP?
Register $30 is reserved, by software convention, for use as a frame pointer. In the extended assembler it has the mnemonic name $fp . When a subroutine starts running, the frame pointer and the stack pointer contain the same address. While the subroutine is active, the frame pointer, points at the top of the stack.
What is a patched binary?
Binary patching is the process of modifying a compiled executable to change the code that is run. Radare allows for assembly code to be written inline, compiled and inserted into the binary without any hassle.
How to change assembly instruction in IDA Pro?
If it is your case, edit the cfg/idagui.cfg file, look for the DISPLAY_PATCH_SUBMENU = NO line and change the setting. On the next IDA session, you will be able to change single byte / word values or assemble some code like in OllyDbg.
How to change the zero flag in IDA Pro?
We can simply change the zero flag by right clicking on the ZF value and choosing “Increment value”. This will increment the ZF to 1 from 0, thus causing the JNZ instruction to take the correct password message. I will demonstrate method number 1. You may re-run this example and try method 2 if you wish.
What’s the best way to update the Ida database?
If the former, the easiest way is to upgrade to IDA 6.2 or later which includes a “Edit/Patch/Apply patches to input file” menu option that pushes all the changes into the original binary without the need to generate a dif file. If the latter, the easiest thing is the simply use the hex view to edit the database.
How to create a diff file in IDA Pro?
Once you have patched your database, go to File / Produce file / Create DIF file, it will let you create a simple diff file in the form offset / value before / value after (it is not the common diff file format) To apply the diff file to an existing file, you can use the source code of a dif file patcher that was released in the IDA Pro Book