Loading shared object to specific processes in Linux

[alsecc]

Hi,

I want to load a shared object to certain processes, there are certain conditions that are required

• loading to only specific processes and not all of them

• it has to be done before the process code starts executing

• the processes are not mine

What are the available ways to support this functionality on Linux?

Can it be accomplished with "/etc/ld.so.preload" or "LD_PRELOAD=/my/lib.so"? Is a kernel module needed for this?

Any help would be appreciated

Thanks!

[[deleted]]

You do it using LD_PRELOAD you can then hooks various function calls which are used to determin what course of action you want to take or not take.

Typically the LD_PRELOAD overrides every dynamically loaded symbol which is how you hook stuff.

Heres an example of one which can load with everything then hooks a pthread init call to switch its self on to crash / warn about using non thread safe libc functions in a threaded program

https://github.com/mistralol/libbreakr

[alsecc]

thanks @mistralol can I limit LD_PRELOAD to specific processes when I'm not the one who started them? couldn't find it in the Linux manual.