[#1823] replace malloc/calloc/strdup/free with openssl allocator

[songlingatpan]

Replaced malloc, calloc, strdup, and free with the OpenSSL memory allocator to enable the caller to customize memory allocator, addressing issue #1823. This PR does not change the existing behavior or algorithms.

[songlingatpan]

I will commit another change for copy_from_upstream.

[baentsch]

Conceptually LGTM, but CI needs to pass; please see https://github.com/open-quantum-safe/liboqs/blob/main/CONTRIBUTING.md#coding-style

[songlingatpan]

@baentsch Question: 'bike', 'frodokem', 'ntruprime' is not from upstream.
To replace malloc with OQS_MEM_malloc, where should i modify the code? Thanks
liboqs/src/kem/frodokem/kem_frodokem976shake.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/frodokem/kem_frodokem640aes.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/frodokem/kem_frodokem1344shake.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/frodokem/kem_frodokem976aes.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/frodokem/kem_frodokem1344aes.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/frodokem/kem_frodokem640shake.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/kem.h:264:OQS_API void OQS_KEM_free(OQS_KEM *kem); liboqs/src/kem/ntruprime/kem_ntruprime_sntrup761.c:11: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/kem.c:493:OQS_API void OQS_KEM_free(OQS_KEM *kem) { liboqs/src/kem/bike/kem_bike.c:9: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/bike/kem_bike.c:34: OQS_KEM *kem = malloc(sizeof(OQS_KEM)); liboqs/src/kem/bike/kem_bike.c:59: OQS_KEM *kem = malloc(sizeof(OQS_KEM));

[baentsch]

Question: 'bike', 'frodokem', 'ntruprime' is not from upstream.

Good point. @dstebila : There's surely upstreams for these algorithms, but they're not captured by OQS automation/copy_from_upstream. Question: Are these projects still maintained (and where) or is it OK to change code straight in liboqs for these algs? If the former, what would it take to bring them in via "copy_from_upstream"? If the latter, should we remove them completely from OQS?

[dstebila]

Question: 'bike', 'frodokem', 'ntruprime' is not from upstream.

Good point. @dstebila : There's surely upstreams for these algorithms, but they're not captured by OQS automation/copy_from_upstream. Question: Are these projects still maintained (and where) or is it OK to change code straight in liboqs for these algs? If the former, what would it take to bring them in via "copy_from_upstream"? If the latter, should we remove them completely from OQS?

FrodoKEM is maintained at https://github.com/microsoft/PQCrypto-LWEKE/; I exported the code from there any manually added it to liboqs, as we didn't have as robust a copy_from_upstream at the time. FrodoKEM also needs to do an update from upstream, as there have been new variants introduced in the last year, but I don't have a plan for this update. So to avoid blocking on that, I would say it's fine to make the FrodoKEM changes directly here in this repository.

NTRUPrime had been coming from PQClean, but they have stopped supporting it. We only are keeping one variant of NTRUPrime because of its use in OpenSSH. I think we consider a timeline for sunsetting it. But in the interim, I think changes to NTRUPrime can be done directly here in this repository.

BIKE was contributed directly by the team at AWS. Our main contact for that has been @dkostic, but I'm not sure if he's still the right contact. Pinging @brian-jarvis-aws for some input.

[songlingatpan]

@dstebila @baentsch @bhess @jschanck
Code change for openssl allocator has been done.
Please review the code.

In addition, there are quite some error handling and potential memory leak.
Would you like to fix them in the current PR? or create a separate PR for review?

Thanks

[songlingatpan]

**baentsch ** requested changes

done

[dstebila]

In addition, there are quite some error handling and potential memory leak. Would you like to fix them in the current PR? or create a separate PR for review?

I'd prefer to see those as a second PR, since those changes may be less mechanical and might require a closer look.

[dstebila]

I suggest we defer merging this until after the 0.11.0 release, otherwise we would need to cut a new release candidate and push the release back a week.

[baentsch]

@songlingatpan most of this LGTM and improves the software (malloc->OQS_MEM_malloc & additional NULL checks). Some things I don't understand (see single comments). What I'm really unsure about is the apparent removal of (many) user-visible allocation error warnings for silent abort()s. Isn't that a step in the wrong direction? Yes, the abort() is a stupid pattern to begin with, but isn't it reasonable to let users at least know why the lib/app suddenly stopped?

[songlingatpan]

@songlingatpan most of this LGTM and improves the software (malloc->OQS_MEM_malloc & additional NULL checks). Some things I don't understand (see single comments). What I'm really unsure about is the apparent removal of (many) user-visible allocation error warnings for silent abort()s. Isn't that a step in the wrong direction? Yes, the abort() is a stupid pattern to begin with, but isn't it reasonable to let users at least know why the lib/app suddenly stopped?

@baentsch
I understand your point.

There was some discussion with @SWilson4 about removing the checked malloc logic. If you review the OpenSSL code, it doesn’t use the checked malloc/abort() pattern. In general, a well-designed library should avoid including abort() or exit() calls, as these decisions should be left to the caller. Ideally, malloc failures should be handled consistently across the codebase by returning error codes, rather than aborting or exiting.

Since there is no fprintf logging for non-checked malloc failures, I didn’t add stderr output for abort(). I recommend fully removing abort() in the 0.12.0 release.

Our in-house version is much more stable than 0.11.0 and target for production readiness compared to the official liboqs repository. However, I’m facing challenges in integrating our in-house code changes back into the official liboqs due to abort(), and so on.

Anyway I can add fprintf back for abort.

[baentsch]

Anyway I can add fprintf back for abort.

That'd be nice. And for the avoidance of doubt: My ask (to achieve this) is basically to reduce the amount of new code (by retaining "OQS_MEM_checked_malloc" calls), not to add more new code (fprintf statements, I guess)

[songlingatpan]

Anyway I can add fprintf back for abort.

That'd be nice. And for the avoidance of doubt: My ask (to achieve this) is basically to reduce the amount of new code (by retaining "OQS_MEM_checked_malloc" calls), not to add more new code (fprintf statements, I guess)

@baentsch We can remove the checked malloc for now.
In the next step, we can remove abort and add return proper error and fix potential memory leaks.
If you target to the production, eventually we need to remove the checked malloc and do proper error handling and release resources, etc.

[songlingatpan]

Anyway I can add fprintf back for abort.

That'd be nice. And for the avoidance of doubt: My ask (to achieve this) is basically to reduce the amount of new code (by retaining "OQS_MEM_checked_malloc" calls), not to add more new code (fprintf statements, I guess)

@baentsch We can remove the checked malloc for now. In the next step, we can remove abort and add return proper error and fix potential memory leaks. If you target to the production, eventually we need to remove the checked malloc and do proper error handling and release resources, etc.

Please let me know if you still want to keep the checked malloc. Still, if you check openssl code, there is no checked malloc. We need to remove it eventually.

[songlingatpan]

@baentsch Please review the PR.

Thanks