Freaks City

After skimming lecture slides and skimming the textbook, I still felt hazy, so I decided to learn by doing and tackle CMU’s famous "bomb" lab. The goal is simple: supply the correct input strings to six successive phases before the program calls explode_bomb. All phases live in the same ELF-64 executable, so the first step is to dump ...

GDB Debuggging Commands and Advanced Debugging Scenarios Core GDB Operations GDB requires executables compiled with debugging symbols using the -g flag during compilation: gcc -g source.c -o executable Essential Commands quit - Terminate debugging session list - Display source code segments list 5,10 shows lines 5 through 10 list file.c:5,10 ...

The challenge can be downloaded from: Download Link (Password: 0000) Solution Approach ret2libc involves hijacking program control flow to execute funcsions from the standard C library (libc). Typically, this is achieved by redirecting execution to a function's PLT entry or a specific address within the GOT table. Usual, the goal is to invoke s ...

When a C program compiles without errors or warnings using gcc but produces incorrect output or crashes (e.g., segmentation fault), the GNU Debugger (gdb) becomes essential for identifying the root cause. Similar to debug modes in IDEs like Keil, gdb alllows setting breakpoints and inspecting variable values during execution to isolate bugs. Co ...

Enabling Core Dumps and Interactive Debugging Runtime segmentation faults in C++ network applications frequently occur during resource initialization phases. By default, Linux restricts core dump generation to conserve disk space. The ulimit -c command reveals the current limit; a return value of 0 indicates suppression. Executing ulimit -c unl ...

Printing the stack trace is a common debugging technique, especially useful when a system encounters an exception. By capturing the stack at the time of the anomaly, it becomes much easier to pinpoint errors. This article will focus on using backtrace for stack printing. More advanced techniques, such as analyzing core files with gdb, may be ex ...

When GDB displays function names as ??() in stack traces, it indicates that the function names cannot be resolved. This typically occurs due to several reasons: Missing Symbol Table Information: If the executable lacks symbol table information or GDB fails to load it, function names and code locations become unavailable. This can happen if deb ...

Locating Segmentation Faults with GDB and Core Dumps Ensure the source code is compiled with the -g flag to embed debugging symbols. Check core file size limit: Run ulimit -c. A return value of 0 means core dumps are disabled; unlimited means no size restriction. Use ulimit -a to view all resource limits. Enable unlimited core size: ulimit -c ...

Stack Frame Navigation and Memory Inspection When analyzing a crashed application, navigating the call stack is essential. The bt (backtrace) command lists the function calls leading to the current point. To inspect variables within a specific stack frame, use the frame command followed by the frame index. (gdb) bt #0 AsyncWorker::Execute (thi ...