Sunday, February 26, 2023

Reverse Engineering Notes - _ITM_addUserCommitAction


what is _ITM_addUserCommitAction?

_ITM_addUserCommitAction is a symbol that is automatically generated by the GCC compiler when building programs with instrumentation enabled. It is used to register a function to be called after every transactional memory commit.

Transactional memory is a programming paradigm that allows multiple threads to work with shared data in a way that is similar to a database transaction. When a thread wants to modify shared data, it first enters a transaction, performs its operations, and then commits the transaction to make the changes visible to other threads.

The _ITM_addUserCommitAction function allows programmers to register a callback function that will be called after every transactional memory commit. This can be useful for performing certain operations that should occur only after the transaction has been completed successfully, such as logging or checkpointing.

Note that the _ITM_addUserCommitAction function is only generated when compiling with GCC's transactional memory support enabled, which requires a specific flag (-fgnu-tm) to be passed to the compiler. If you don't use this flag, you won't see this symbol in your program's imports or exports.

 how does it relate to reverse engineering?

In the context of reverse engineering, _ITM_addUserCommitAction can be seen as an indicator that the original program was compiled with GCC's transactional memory support enabled.

Knowing this information can be useful when analyzing a program, as it can provide insight into the original programmer's intent and the design of the program. It can also help to identify potential bugs or vulnerabilities that may be related to the use of transactional memory.

Additionally, the presence of the _ITM_addUserCommitAction symbol can be a useful clue when debugging or reverse engineering a program. By setting a breakpoint on this symbol or analyzing its usage in the program's code, a reverse engineer may be able to gain a better understanding of the program's behavior and control flow.


No comments:

Post a Comment

A Guide to Multi-Level Pointer Analysis

  A Comprehensive Guide to Multi-Level Pointer Analysis   A regular pointer points to only one address, but when it's accompanied by a l...