[openssl/openssl] 235ef9: Fix potential NULL pointer dereference

[Juergen Christ]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 235ef96049dbe337a3c3c5d419dacbb5a81df1b3
      https://github.com/openssl/openssl/commit/235ef96049dbe337a3c3c5d419dacbb5a81df1b3
  Author: Juergen Christ <jchrist at linux.ibm.com>
  Date:   2023-01-17 (Tue, 17 Jan 2023)

  Changed paths:
    M providers/implementations/keymgmt/ec_kmgmt.c

  Log Message:
  -----------
  Fix potential NULL pointer dereference

In EC key generation, if allocation of struct ec_gen_ctx fails, values
provided by parameters are copied into the context at represented by a NULL
pointer.  To fix this, prevent copy if allocation fails.

Signed-off-by: Juergen Christ <jchrist at linux.ibm.com>

Reviewed-by: Paul Dale <pauli at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/20055)