Shall symbols ever be implicitly added?

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Shall symbols ever be implicitly added?

Czcibor Bohusz-Dobosz
Hello,

I have recently been researching the possibility of using libtcc to make
C a highly efficient scripting language for my codebase. The idea is
certainly very promising - at a similar level of visible abstraction,
TCC takes two seconds to allocate a single-gigabyte array on my setup,
Lua takes about five... to trigger OOM :-)

However, it appears that if if I use the -rdynamic flag while compiling
the codebase, the TCC state is being given access to symbols that have
not been explicitly added to it - I've attached the code of a simple
program showcasing the issue. Because CMake exposes this flag by default
to the *nix compiler toolchains (spent quite a while scratching my
head...), this may be a fairly serious vulnerability if unnoticed.

I would therefore love to get an answer on whether the described
behavior is intentional. If it indeed is - TCC should probably get it
visibly documented for the benefit of security and easier adoption of
the library. If not - well, I've tried to fix it and failed (or rather,
succeeded while making a thousand other things break, by changing
RTLD_DEFAULT to RTLD_NEXT in tccelf.c:823), so if anybody here happened
to be blessed with actual know-how... :-)

Thank You a thousand times to all the great contributors to this
outstanding project!

- Czcibor


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