On Sat, Feb 11, 2017 at 08:54:39PM +0000, Jo�o Valverde wrote:
[..]
> I think a small abstraction layer above the lower-level crypto routines,
> whatever those may be (libgcrypt, nettle, home-grown - yuck), would be a
> useful thing to have. It would accomplish two things:
>
> 1. Easily change dependencies without having to change dissector code.
>
> 2. Disable crypto in a saner way and keep the dependency optional, without
> having to use #ifdefs all over the place (just one place in fact). Example:
>
> int ws_aes_decrypt(...) {
> #ifdef HAVE_AES_DEPENDENCY
> err = aes_decrypt(...);
> if (err == AES_OK) {
> return WS_CRYPTO_OK;
> } else {
> ...
> }
> #else
> return WS_CRYPTO_DISABLED;
> #endif
> }
>
> Then of course require crypto consumers (dissectors and whatever else) to
> handle the WS_CRYPTO_DISABLED case as appropriate.
Disabling is an option if you want to make the crypto library optional,
but the vast majority of the files/functions are hash functions (md5 is
used for example in editcap.c for duplicate detection). Since you need a
crypto library for the hash functions, you get decryption algorithms
like AES for free. (Unless you want to keep the bundled algorithms... I
would rather not).
At this moment I don't know how the end result looks like. Maybe after
actually looking at the files/functions, we'll see whether an extra
abstraction is worth it or not.
--
Kind regards,
Peter Wu
https://lekensteyn.nl