[openssl/openssl] d521c9: Fix NULL pointer deref when parsing the stable sec...

[Neil Horman]

  Branch: refs/heads/openssl-3.1
  Home:   https://github.com/openssl/openssl
  Commit: d521c94e7b440f043bcdfdf7575c6bf8a362ded0
      https://github.com/openssl/openssl/commit/d521c94e7b440f043bcdfdf7575c6bf8a362ded0
  Author: Neil Horman <nhorman at openssl.org>
  Date:   2024-01-12 (Fri, 12 Jan 2024)

  Changed paths:
    M crypto/asn1/asn_mstbl.c
    A test/asn1_stable_parse_test.c
    M test/build.info
    A test/recipes/04-test_asn1_stable_parse.t
    A test/recipes/04-test_asn1_stable_parse_data/asn1_stable_parse.cnf

  Log Message:
  -----------
  Fix NULL pointer deref when parsing the stable section

When parsing the stable section of a config such as this:
openssl_conf = openssl_init
[openssl_init]
stbl_section = mstbl
[mstbl]
id-tc26 = min

Can lead to a SIGSEGV, as the parsing code doesnt recognize min as a
proper section name without a trailing colon to associate it with a
value.  As a result the stack of configuration values has an entry with
a null value in it, which leads to the SIGSEGV in do_tcreate when we
attempt to pass NULL to strtoul.

Fix it by skipping any entry in the config name/value list that has a
null value, prior to passing it to stroul

Reviewed-by: Matt Caswell <matt at openssl.org>
Reviewed-by: Tomas Mraz <tomas at openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22988)

(cherry picked from commit 0981c20f8efa68bf9d68d7715280f83812c19a7e)