This section holds executable instructions that contribute to the process termination code. That is, when a program exits normally, the system arranges to execute the code in this section

This section holds executable instructions that contribute to the process initialization code. That is, when a program starts to run the system arranges to execute the code in this section before the main program entry point (called main in C programs)

From: http://l4u-00.jinr.ru/usoft/WWW/www_debian.org/Documentation/elf/node3.html

(from StackOverflow) PLT stands for Procedure Linkage Table which is, put simply, used to call external procedures/functions whose address isn't known in the time of linking, and is left to be resolved by the dynamic linker at run time.

It is jump table to functions that are in the dynamically linked libraries (printf, scanf,...).

Further reading: https://www.technovelty.org/linux/plt-and-got-the-key-to-code-sharing-and-dynamic-libraries.html

The instruction at offset 0x55 references printf. The linker better solve this reference.

The instruction at offset 0x3f references foo. The linker uses this information.

All the symbols with UNDefined must be resolved by the linker.

Read Only Data: Here you would find string literals such as the "result is %d"

For programs compiled with -c option, this section provides information to the link editor ld where and how to "patch" executable code in .text section

Comments about the compiler. You may read the raw content of any of these sections using: objdump -s -j .comment

The .data section contains data :-)

The .text section contains the machine language instructions of the program.

ELF files are subdivided into sections.

A section is an area in the object file that contains information which is useful for linking: program's code, program's data (variables, array, string), relocation information and other. So, in each area, several information is grouped and it has a distinct meaning: code section only hold code, data section only holds initialized or non-initialized data, etc

The first function in this file is at address 0x0.

32-bit ELF

The magic sequence that starts an ELF file is 0x7f 0x45 0x4c 0x46, i.e. .ELF.

You can read about the cfi assembler directives in https://sourceware.org/binutils/docs/as/CFI-directives.html#CFI-directives.

They are merely instructions for the assembler, similar to the preprocessor directives that you include in your C programs.

When you compile using the gcc -fno-stack-protector, there is no validation of the stack at the end of the function.

This was compiled for 32 bits, notice that the parameter to foo is being received through the stack.

This program was compiled for 64 bits and the parameter to the foo function is passed through register %edi.

The return value is passed through register %eax.

Setting the parameter and invoking foo.

Information about the compiler.

By default, the gcc compiler includes instructions to detect stack smashing.

Setting the parameters and calling the printf function.

The .text section contains the actual assembly language instructions.

This is saying "In this program there is a global variable called buffer of 1048576 bytes and 32-bit alignment.

.comm name, size,alignment

The '.comm' directive allocates storage in the data section.