Overflow if co_linetable is absurdly large

[federicovalenso]

Bug report

Bug description:

f.__code__ = f.__code__.replace(co_linetable=bytes(bytearray(2**31+1)))

It could lead to overflow in write_location_info_entry.

CPython versions tested on:

3.11

Operating systems tested on:

Linux

[picnixz]

Actually, how is co_linetable related to a_linetable? Namely, can you write me a complete PoC please?

[skirpichev]

bytes(bytearray(2**31+1))

I think this issue, as well as #126860 or #126858 is all about: in CPython we use native machine-sized integers to keep some counters for code or ast objects. It's not an issue, unless some CPython's code wrongly sets such counters.

I suggest closing all these issues.

[picnixz]

Now that I remember, the co_linetable has some specific shape so we need to instrumentalize it correctly (see InternalDocs/code_objects.md for details). I'm going to close this one as wont fix unless a simple reproducer is available (it should be possible but honestly I don't think it's worth our time for this one).