From fe34a2a0e44bc80ff213bfd185046a5f10c94997 Mon Sep 17 00:00:00 2001
From: Chris Lamb <chris@chris-lamb.co.uk>
Date: Wed, 2 Jan 2019 18:06:16 +0000
Subject: [PATCH] Make the sp_lstchg shadow field reproducible (re. #71)

From <https://github.com/shadow-maint/shadow/pull/71>:

```
The third field in the /etc/shadow file (sp_lstchg) contains the date of
the last password change expressed as the number of days since Jan 1, 1970.
As this is a relative time, creating a user today will result in:

username:17238:0:99999:7:::
whilst creating the same user tomorrow will result in:

username:17239:0:99999:7:::
This has an impact for the Reproducible Builds[0] project where we aim to
be independent of as many elements the build environment as possible,
including the current date.

This patch changes the behaviour to use the SOURCE_DATE_EPOCH[1]
environment variable (instead of Jan 1, 1970) if valid.
```

This updated PR adds some missing calls to gettime (). This was originally
filed by Johannes Schauer in Debian as #917773 [2].

[0] https://reproducible-builds.org/
[1] https://reproducible-builds.org/specs/source-date-epoch/
[2] https://bugs.debian.org/917773
---
 libmisc/pwd2spwd.c | 3 +--
 src/pwck.c         | 2 +-
 src/pwconv.c       | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/libmisc/pwd2spwd.c b/libmisc/pwd2spwd.c
index c1b9b29a..6799dd50 100644
--- a/libmisc/pwd2spwd.c
+++ b/libmisc/pwd2spwd.c
@@ -40,7 +40,6 @@
 #include "prototypes.h"
 #include "defines.h"
 #include <pwd.h>
-extern time_t time (time_t *);
 
 /*
  * pwd_to_spwd - create entries for new spwd structure
@@ -66,7 +65,7 @@ struct spwd *pwd_to_spwd (const struct passwd *pw)
 		 */
 		sp.sp_min = 0;
 		sp.sp_max = (10000L * DAY) / SCALE;
-		sp.sp_lstchg = (long) time ((time_t *) 0) / SCALE;
+		sp.sp_lstchg = (long) gettime () / SCALE;
 		if (0 == sp.sp_lstchg) {
 			/* Better disable aging than requiring a password
 			 * change */
diff --git a/src/pwck.c b/src/pwck.c
index 0ffb711e..f70071b1 100644
--- a/src/pwck.c
+++ b/src/pwck.c
@@ -609,7 +609,7 @@ static void check_pw_file (int *errors, bool *changed)
 					sp.sp_inact  = -1;
 					sp.sp_expire = -1;
 					sp.sp_flag   = SHADOW_SP_FLAG_UNSET;
-					sp.sp_lstchg = (long) time ((time_t *) 0) / SCALE;
+					sp.sp_lstchg = (long) gettime () / SCALE;
 					if (0 == sp.sp_lstchg) {
 						/* Better disable aging than
 						 * requiring a password change
diff --git a/src/pwconv.c b/src/pwconv.c
index 9c69fa13..f932f266 100644
--- a/src/pwconv.c
+++ b/src/pwconv.c
@@ -267,7 +267,7 @@ int main (int argc, char **argv)
 			spent.sp_flag   = SHADOW_SP_FLAG_UNSET;
 		}
 		spent.sp_pwdp = pw->pw_passwd;
-		spent.sp_lstchg = (long) time ((time_t *) 0) / SCALE;
+		spent.sp_lstchg = (long) gettime () / SCALE;
 		if (0 == spent.sp_lstchg) {
 			/* Better disable aging than requiring a password
 			 * change */