apps: ca,req,x509: Add explicit start and end dates options

- Added options `-not_before` (start date) and `-not-after` (end date)
  for explicit setting of the validity period of a certificate in the
  apps `ca`, `req` and `x509`
- The new options accept time strings or "today"
- In app `ca`, use the new options as aliases of the already existing
  options `-startdate` and `-enddate`
- When used in apps `req` and `x509`, the end date must be >= the start
  date, in app `ca` end date < start date is also accepted
- In any case, `-not-after` overrides the `-days` option
- Added helper function `check_cert_time_string` to validate given
  certificate time strings
- Use the new helper function in apps `ca`, `req` and `x509`
- Moved redundant code for time string checking into `set_cert_times`
  helper function.
- Added tests for explicit start and end dates in apps `req` and `x509`
- test: Added auxiliary functions for parsing fields from `-text`
  formatted output to `tconversion.pl`
- CHANGES: Added to new section 3.4

Signed-off-by: Stephan Wurm <atomisirsi@gsklan.de>

Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/21716)

1 files changed, 7 insertions, 1 deletions

diff --git a/CHANGES.md b/CHANGES.md
index 5bbc34549e..a15321dda9 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -12,6 +12,7 @@ appropriate release branch.
 OpenSSL Releases
 ----------------
 
+ - [OpenSSL 3.4](#openssl-34)
  - [OpenSSL 3.3](#openssl-33)
  - [OpenSSL 3.2](#openssl-32)
  - [OpenSSL 3.1](#openssl-31)
@@ -28,7 +29,12 @@ OpenSSL 3.4
 
 ### Changes between 3.3 and 3.4 [xx XXX xxxx]
 
- * None yet
+ * Added options `-not_before` and `-not_after` for explicit setting
+   start and end dates of certificates created with the `req` and `x509`
+   apps. Added the same options also to `ca` app as alias for
+   `-startdate` and `-enddate` options.
+
+   *Stephan Wurm*
 
 OpenSSL 3.3
 -----------