From c415f5af55499473ca5fccbf1c0805002c108cff Mon Sep 17 00:00:00 2001
From: Tomas Korbar <tkorbar@redhat.com>
Date: Fri, 14 Aug 2026 14:48:18 +0200
Subject: [PATCH] Fix UTC offset calculation in Date headers

sendout.c change based on a patch proposed by Mason Loring Bliss

Resolves: RHEL-232782
---
 mailx-12.5-utc-offset.patch | 101 ++++++++++++++++++++++++++++++++++++
 mailx.spec                  |  10 +++-
 2 files changed, 110 insertions(+), 1 deletion(-)
 create mode 100644 mailx-12.5-utc-offset.patch

diff --git a/mailx-12.5-utc-offset.patch b/mailx-12.5-utc-offset.patch
new file mode 100644
index 0000000..1781a9b
--- /dev/null
+++ b/mailx-12.5-utc-offset.patch
@@ -0,0 +1,101 @@
+From: Tomas Korbar <tkorbar@redhat.com>
+Subject: [PATCH] Fix UTC offset calculation using tm_gmtoff
+
+The UTC offset was derived via mktime(gmtime()) with a manual +1 hour
+DST adjustment.  That breaks with modern tzdata (e.g. America/Vancouver
+in tzdata >= 2026b, Europe/Dublin negative DST).  Use tm_gmtoff from
+localtime() instead, matching s-nail commit 60ed19eed5.
+
+The sendout.c change is identical to a patch proposed by Mason Loring
+Bliss (RHEL-232782).  head.c and imap.c are updated with the same
+tm_gmtoff approach.
+
+Reported-by: Mason Loring Bliss <mason@blisses.org>
+Resolves: RHEL-232782
+---
+ sendout.c |  6 ++----
+ head.c    |  7 +------
+ imap.c    | 17 +++++------------
+ 3 files changed, 8 insertions(+), 22 deletions(-)
+
+--- a/sendout.c
++++ b/sendout.c
+@@ -1149,13 +1149,11 @@
+ 	int tzdiff, tzdiff_hour, tzdiff_min;
+ 
+ 	time(&t);
+-	tzdiff = t - mktime(gmtime(&t));
++	tmptr = localtime(&t);
++	tzdiff = tmptr->tm_gmtoff;
+ 	tzdiff_hour = (int)(tzdiff / 60);
+ 	tzdiff_min = tzdiff_hour % 60;
+ 	tzdiff_hour /= 60;
+-	tmptr = localtime(&t);
+-	if (tmptr->tm_isdst > 0)
+-		tzdiff_hour++;
+ 	return fprintf(fo, "%s: %s, %02d %s %04d %02d:%02d:%02d %+05d\n",
+ 			field,
+ 			weekday_names[tmptr->tm_wday],
+--- a/head.c
++++ b/head.c
+@@ -1081,7 +1081,6 @@
+ 	char	*fp, *xp;
+ 	time_t	t;
+ 	int	i, year, month, day, hour, minute, second;
+-	int	tzdiff;
+ 	struct tm	*tmptr;
+ 
+ 	for (fp = from; *fp && *fp != '\n'; fp++);
+@@ -1116,11 +1115,8 @@
+ 	if ((t = combinetime(year, month, day, hour, minute, second)) ==
+ 			(time_t)-1)
+ 		goto invalid;
+-	tzdiff = t - mktime(gmtime(&t));
+ 	tmptr = localtime(&t);
+-	if (tmptr->tm_isdst > 0)
+-		tzdiff += 3600;
+-	t -= tzdiff;
++	t += tmptr->tm_gmtoff;
+ 	return t;
+ invalid:
+ 	time(&t);
+--- a/imap.c
++++ b/imap.c
+@@ -3508,7 +3508,7 @@
+ imap_read_date(const char *cp)
+ {
+ 	time_t	t;
+-	int	year, month, day, i, tzdiff;
++	int	year, month, day, i;
+ 	struct tm	*tmptr;
+ 	char	*xp, *yp;
+ 
+@@ -3532,11 +3532,8 @@
+ 		return -1;
+ 	if ((t = combinetime(year, month, day, 0, 0, 0)) == (time_t)-1)
+ 		return -1;
+-	tzdiff = t - mktime(gmtime(&t));
+ 	tmptr = localtime(&t);
+-	if (tmptr->tm_isdst > 0)
+-		tzdiff += 3600;
+-	t -= tzdiff;
++	t += tmptr->tm_gmtoff;
+ 	return t;
+ }
+ 
+@@ -3547,13 +3544,11 @@
+ 	struct tm	*tmptr;
+ 	int	tzdiff, tzdiff_hour, tzdiff_min;
+ 
+-	tzdiff = t - mktime(gmtime(&t));
++	tmptr = localtime(&t);
++	tzdiff = tmptr->tm_gmtoff;
+ 	tzdiff_hour = (int)(tzdiff / 60);
+ 	tzdiff_min = tzdiff_hour % 60;
+ 	tzdiff_hour /= 60;
+-	tmptr = localtime(&t);
+-	if (tmptr->tm_isdst > 0)
+-		tzdiff_hour++;
+ 	snprintf(s, sizeof s, "\"%02d-%s-%04d %02d:%02d:%02d %+03d%02d\"",
+ 			tmptr->tm_mday,
+ 			month_names[tmptr->tm_mon],
diff --git a/mailx.spec b/mailx.spec
index 0508067..38a66a5 100644
--- a/mailx.spec
+++ b/mailx.spec
@@ -4,7 +4,7 @@
 Summary: Enhanced implementation of the mailx command
 Name: mailx
 Version: 12.5
-Release: 29%{?dist}
+Release: 30%{?dist}
 # MPLv1.1 .. nss.c, nsserr.c
 License: BSD with advertising and MPLv1.1
 Group: Applications/Internet
@@ -41,6 +41,8 @@ Patch13: mailx-12.5-encsplit.patch
 Patch14: mailx-12.5-openssl.patch
 # resolves: #1602614
 Patch15: mailx-12.5-coverity.patch
+# resolves: RHEL-232782
+Patch16: mailx-12.5-utc-offset.patch
 
 BuildRequires: gcc
 
@@ -91,6 +93,7 @@ as well as "nail" (the initial name of this project).
 %patch13 -p1
 %patch14 -p1
 %patch15 -p1
+%patch16 -p1
 sed -i 's,/etc/nail.rc,%{mailrc},g' mailx.1
 
 
@@ -168,6 +171,11 @@ popd
 
 
 %changelog
+* Fri Aug 14 2026 Tomas Korbar <tkorbar@redhat.com> - 12.5-30
+- Fix UTC offset calculation in Date headers; sendout.c change based on
+  a patch proposed by Mason Loring Bliss
+- Resolves: RHEL-232782
+
 * Thu Oct 18 2018 Nikola Forró <nforro@redhat.com> - 12.5-29
 - fix important Covscan defects
   resolves: #1602614