[openssl/openssl] 438c13: Fix a possible memleak in PKCS7_add_attrib_smimecap

[Bernd Edlinger]

  Branch: refs/heads/openssl-3.0
  Home:   https://github.com/openssl/openssl
  Commit: 438c137a9d9c8767d9536965206df525477841c8
      https://github.com/openssl/openssl/commit/438c137a9d9c8767d9536965206df525477841c8
  Author: Bernd Edlinger <bernd.edlinger at hotmail.de>
  Date:   2023-11-22 (Wed, 22 Nov 2023)

  Changed paths:
    M crypto/pkcs7/pk7_attr.c

  Log Message:
  -----------
  Fix a possible memleak in PKCS7_add_attrib_smimecap

When PKCS7_add_signed_attribute fails, the ASN1_STRING
object may be leaked.

Reviewed-by: Neil Horman <nhorman at openssl.org>
Reviewed-by: Shane Lontis <shane.lontis at oracle.com>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
Reviewed-by: Richard Levitte <levitte at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22744)

(cherry picked from commit ed3d2771278cfa1c355b40c681f5acc8404156c6)