[openssl-dev] [openssl.org #4589] simplifying writing code that is 1.0.x and 1.1.x compatible

[Thomas Waldmann via RT]

Hi,

at borgbackup project, we are currently trying to make it compatible
with OpenSSL 1.0.x and 1.1.x.

For the opaque cipher ctx this worked quite easily like this:

https://github.com/borgbackup/borg/pull/1193/files#diff-85ee6ebe1cdcfd4a4699c3913d519b27R23

I could not have a cipher ctx structure as a instance variable, but a
pointer to one worked. I am just computing the current IV myself, so I
do not need to reach into the ctx (I need to do that anyway to support
gcm mode).

I used EVP_CIPHER_CTX_new/free() - although not in the man page, they
are there since 0.98 (and the wiki examples use them, too).

Solved.

In borgbackup 1.2, we will also need the flexible (not single-call)
interface to HMAC and I could get it working using the same method as
above (using a pointer and the new/free functions - we do not access
into hmac ctx here, so it is even simpler).

But: HMAC_CTX_{new/free} are not available on 1.0.x. :-(

So my question / request: could these functions be added to a future
update, like 1.0.2i, to simplify migration / portability of code?

I suspect that these 2 functions are very simple to backport from 1.1 to
1.0.x.

Cheers,

Thomas

-- 

GPG ID: FAF7B393
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