[openssl/openssl] db30d8: Check for private key existence before calling edd...

[Wangchong Zhou]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: db30d8f90d8d143d3c294b243af4f77babbb320f
      https://github.com/openssl/openssl/commit/db30d8f90d8d143d3c294b243af4f77babbb320f
  Author: Wangchong Zhou <fffonion at gmail.com>
  Date:   2022-11-04 (Fri, 04 Nov 2022)

  Changed paths:
    M providers/implementations/signature/eddsa_sig.c
    M test/evp_extra_test.c

  Log Message:
  -----------
  Check for private key existence before calling eddsa sign functions

Fixes #19524

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19525)

(cherry picked from commit f5a10d5cc19215ab22be55b4a2ee1e41bd38fb14)