gdb.debug(env) affects gdbserver

[mzr]

Setting LD_PRELOAD as in gdb.debug(... ,env={'LD_PRELOAD' : './some.so'}) makes gdbserver itself use that some.so library. Currently I see no mechanism in pwntools allowing specifying env only for the debugged process.

It's been kind of fixed in #1083, yet gdbserver can give different outputs than those starting with "ERROR:".

--wrapper option could solve that problem.
gdbserver --wrapper env 'LD_PRELOAD=./libefence.so' -- :1234 ./test-program
gdbserver manual

[zachriggle]

You will have to use “set env” in the gdbscript

On Wed, May 8, 2019 at 2:31 PM Jan Mazur ***@***.***> wrote: Setting LD_PRELOAD as in gdb.debug(... ,env={'LD_PRELOAD' : './some.so'}) makes gdbserver itself use that some.so library. Currently I see no mechanism in pwntools allowing specifying env only for the debugged process. It's been kind of fixed in #1083 <#1083>, yet gdbserver can give different outputs than those starting with "ERROR:". --wrapper option could solve that problem. gdbserver --wrapper env 'LD_PRELOAD=./libefence.so' -- :1234 ./test-program gdbserver manual <http://man7.org/linux/man-pages/man1/gdbserver.1.html> — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1307>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAA3IGGKLB7TEPNNGIVFVPTPUMTC7ANCNFSM4HLUSOJA> .

-- *Zach Riggle*

[zachriggle]

On follow-up, I'm not sure the best way to handle this. The current way we do this is to set the environment on gdbserver which is inherited by the child binary (which you pointed out). This causes issues on LD_PRELOAD, specifically.

We might want to special-case tricky environment variables like this and PATH. It looks like we can do the following:

gdbserver --wrapper env LD_PRELOAD=libtest.so -- 

I can't contribute to Pwntools anymore (employer), but if you submit a PR I can merge it.