[openssl/openssl] 755126: fix: reject adding a duplicity into STACK_OF(X509_...

[Adam Šulc]

  Branch: refs/heads/master
  Home:   https://github.com/openssl/openssl
  Commit: 7551264186f176ca5801aa84d60c7b91d8fba31f
      https://github.com/openssl/openssl/commit/7551264186f176ca5801aa84d60c7b91d8fba31f
  Author: Adam Šulc <sulcadam12 at gmail.com>
  Date:   2023-07-24 (Mon, 24 Jul 2023)

  Changed paths:
    M crypto/x509/x509_att.c

  Log Message:
  -----------
  fix: reject adding a duplicity into STACK_OF(X509_ATTRIBUTE)

Function `X509at_add1_attr()` (crypto/x509/x509_att.c) rejects to add a duplicity into `*x` but it searches in a wrong stack.

Changed to search in `*x`.

CLA: trivial

Reviewed-by: Kurt Roeckx <kurt at roeckx.be>
Reviewed-by: Paul Dale <pauli at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21505)