Client rsa-sha2-512

[ejohnstown]

1. Separate the key type and signature type when handling user authentication. ssh-rsa is a key type used with rsa-sha2-256 and rsa-sha2-512 signatures, along with ssh-rsa signatures.
2. Allow rsa-sha2-512 to be used.
3. Fix bug where setting the key algorithm on the client command line was setting the list to NULL.
4. Fix bug where adding rsa-sha2-512 to the list of canned algorithms was terminating the list, rather that adding it.

Issue: ZD-21247

[Copilot]

Pull request overview

This PR updates wolfSSH client public-key authentication handling so RSA key type (ssh-rsa) can be used with multiple RSA signature algorithms (including rsa-sha2-512), while also fixing algorithm list handling bugs in the example client and canned algorithm name list assembly.

Changes:

• Split WS_KeySignature into separate key type (keyId) vs signature type (sigId) to correctly support RSA SHA-2 signature selection.
• Enable/advertise rsa-sha2-512 in the canned key algorithm list (fixing list concatenation/termination).
• Fix example client so setting a key algorithm list from the command line actually applies the provided list.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
wolfssh/internal.h	Removes prior forced-disable of rsa-sha2-512; updates WS_KeySignature to separate key vs signature metadata.
src/internal.c	Updates auth request building to use sigId for hashing/signing; fixes canned algo list comma handling; adapts to new WS_KeySignature fields.
examples/client/client.c	Fixes client example to pass the configured keyList into wolfSSH_CTX_SetAlgoListKey().

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.