Fix documentation of X509_VERIFY_PARAM_add0_policy()

The function was incorrectly documented as enabling policy checking.

Fixes: CVE-2023-0466

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from #20561)

CHANGES.md

@@ -242,6 +242,13 @@ OpenSSL 3.1
 
 ### Changes between 3.1.0 and 3.1.1 [xx XXX xxxx]
 
+ * Corrected documentation of X509_VERIFY_PARAM_add0_policy() to mention
+   that it does not enable policy checking. Thanks to David Benjamin for
+   discovering this issue.
+   ([CVE-2023-0466])
+
+   *Tomáš Mráz*
+
  * Fixed an issue where invalid certificate policies in leaf certificates are
    silently ignored by OpenSSL and other certificate policy checks are skipped
    for that certificate. A malicious CA could use this to deliberately assert
@@ -19901,6 +19908,7 @@ ndif
 
 <!-- Links -->
 
+[CVE-2023-0466]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0466
 [CVE-2023-0465]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0465
 [CVE-2023-0464]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0464
 [CVE-2023-0401]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0401

NEWS.md

@@ -37,6 +37,7 @@ OpenSSL 3.1
 
 ### Major changes between OpenSSL 3.1.0 and OpenSSL 3.1.1 [under development]
 
+  * Fixed documentation of X509_VERIFY_PARAM_add0_policy() ([CVE-2023-0466])
   * Fixed handling of invalid certificate policies in leaf certificates
     ([CVE-2023-0465])
   * Limited the number of nodes created in a policy tree ([CVE-2023-0464])
@@ -1464,6 +1465,7 @@ OpenSSL 0.9.x
   * Support for various new platforms
 
 <!-- Links -->
+[CVE-2023-0466]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0466
 [CVE-2023-0465]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0465
 [CVE-2023-0464]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0464
 [CVE-2023-0401]: https://www.openssl.org/news/vulnerabilities.html#CVE-2023-0401

doc/man3/X509_VERIFY_PARAM_set_flags.pod

@@ -98,8 +98,9 @@ B<trust>.
 X509_VERIFY_PARAM_set_time() sets the verification time in B<param> to
 B<t>. Normally the current time is used.
 
-X509_VERIFY_PARAM_add0_policy() enables policy checking (it is disabled
-by default) and adds B<policy> to the acceptable policy set.
+X509_VERIFY_PARAM_add0_policy() adds B<policy> to the acceptable policy set.
+Contrary to preexisting documentation of this function it does not enable
+policy checking.
 
 X509_VERIFY_PARAM_set1_policies() enables policy checking (it is disabled
 by default) and sets the acceptable policy set to B<policies>. Any existing
@@ -400,6 +401,10 @@ The X509_VERIFY_PARAM_get_hostflags() function was added in OpenSSL 1.1.0i.
 The X509_VERIFY_PARAM_get0_host(), X509_VERIFY_PARAM_get0_email(),
 and X509_VERIFY_PARAM_get1_ip_asc() functions were added in OpenSSL 3.0.
 
+The function X509_VERIFY_PARAM_add0_policy() was historically documented as
+enabling policy checking however the implementation has never done this.
+The documentation was changed to align with the implementation.
+
 =head1 COPYRIGHT
 
 Copyright 2009-2022 The OpenSSL Project Authors. All Rights Reserved.