Re: [Opensc-devel] Bug in PIN_VERIFY_STRUCTURE and PIN_MODIFY_STRUCTURE

[Ludovic R. <lud...@gm...>]

2013/5/27 Frank Morgner <mo...@in...>:
> Hi!

Hello,

> Enabling compiler warnings, I just found a bug in OpenSC. An array is
> accessed out of bounds. The pull request is issued, but the same bug
> also exists in PCSC-Lite (Drivers/ccid/MacOSX/reader.h and
> PCSC/src/PCSC/reader.h). Ludovic, you might want to have a look:
>
> https://github.com/frankmorgner/OpenSC/commit/e74d33441e87826b3409446d2e7b5c917b2697c4

It is not a bug but a feature.
Ideally I would like to use  abData[0] or abData[] but some compilers complain.
It is called "C99 flexible array member"

Maybe I should use something like
https://github.com/LudovicRousseau/libusbx/commit/53134e90f2f8fc516cc9794d79e754703da9e894

The idea is that the PIN_VERIFY_STRUCTURE is just the _header_ in a
larger structure.
You have to allocate a big enough structure to store the
PIN_VERIFY_STRUCTURE header _and_ the complete APDU.

> And by the way, do you think it is usefull to add
> __attribute__((packed)) to the struct? Otherwise there might be some
> padding between the members...

Good idea. I will have a look.

Bye

--
 Dr. Ludovic Rousseau