doc: clarify -dateopt rfc_822 date format

The rfc_822 date output format uses an asctime-style month-first form.

It does not match RFC 822, RFC 2822, or RFC 5322.

Document the day/month ordering, RFC 822 year length, GMT timezone, and affected commands.

Resolves: https://github.com/openssl/openssl/issues/22223

Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
Reviewed-by: David von Oheimb <david.von.oheimb@siemens.com>
MergeDate: Sun May 10 23:52:21 2026
(Merged from https://github.com/openssl/openssl/pull/29851)

diff --git a/doc/man1/openssl-ca.pod.in b/doc/man1/openssl-ca.pod.in
index bfddadec4e886599b9dfb53810fb4755b81e4c7d..7e75d020db7deba1d763c41ea91cf2329be64db3 100644 (file)
--- a/doc/man1/openssl-ca.pod.in
+++ b/doc/man1/openssl-ca.pod.in
@@ -228,6 +228,14 @@ Don't output the text form of a certificate to the output file.
 Specify the date output format. Values are: rfc_822 and iso_8601.
 Defaults to rfc_822.
 
+Note that despite its name, the rfc_822 format does not conform to RFC 822
+or its successors RFC 2822 and RFC 5322. It outputs dates in the format
+"Mmm DD HH:MM:SS YYYY GMT" (e.g., "Jul 31 22:20:50 2017 GMT"). The month
+appears before the day, unlike all three RFCs, which put the day first.
+The 4-digit year differs from RFC 822 (which used 2-digit years), and the
+timezone name "GMT" is obsolete per RFC 2822 and RFC 5322 (which require
+numeric offsets such as "+0000").
+
 =item B<-startdate> I<date>, B<-not_before> I<date>
 
 This allows the start date to be explicitly set. The format of the

diff --git a/doc/man1/openssl-crl.pod.in b/doc/man1/openssl-crl.pod.in
index 4327b6157b15967e7aca55670b53bb101fb69898..3d12d1700dbf2e324657ea5d35eb77b7f2596955 100644 (file)
--- a/doc/man1/openssl-crl.pod.in
+++ b/doc/man1/openssl-crl.pod.in
@@ -87,6 +87,14 @@ for testing.
 Specify the date output format. Values are: rfc_822 and iso_8601.
 Defaults to rfc_822.
 
+Note that despite its name, the rfc_822 format does not conform to RFC 822
+or its successors RFC 2822 and RFC 5322. It outputs dates in the format
+"Mmm DD HH:MM:SS YYYY GMT" (e.g., "Jul 31 22:20:50 2017 GMT"). The month
+appears before the day, unlike all three RFCs, which put the day first.
+The 4-digit year differs from RFC 822 (which used 2-digit years), and the
+timezone name "GMT" is obsolete per RFC 2822 and RFC 5322 (which require
+numeric offsets such as "+0000").
+
 =item B<-text>
 
 Print out the CRL in text form.

diff --git a/doc/man1/openssl-x509.pod.in b/doc/man1/openssl-x509.pod.in
index f10052b2e7b868fea4a7309aab42177fed2bb002..4309c763faf42d13c4ddd9f0a50b003ac8d8cf3b 100644 (file)
--- a/doc/man1/openssl-x509.pod.in
+++ b/doc/man1/openssl-x509.pod.in
@@ -229,6 +229,14 @@ but are described in the L</Trust Settings> section.
 Specify the date output format. Values are: rfc_822 and iso_8601.
 Defaults to rfc_822.
 
+Note that despite its name, the rfc_822 format does not conform to RFC 822
+or its successors RFC 2822 and RFC 5322. It outputs dates in the format
+"Mmm DD HH:MM:SS YYYY GMT" (e.g., "Jul 31 22:20:50 2017 GMT"). The month
+appears before the day, unlike all three RFCs, which put the day first.
+The 4-digit year differs from RFC 822 (which used 2-digit years), and the
+timezone name "GMT" is obsolete per RFC 2822 and RFC 5322 (which require
+numeric offsets such as "+0000").
+
 =item B<-text>
 
 Prints out the certificate in text form. Full details are printed including the