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Make the sp_lstchg shadow field reproducible.

Browse Source 
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.

 [0] https://reproducible-builds.org/
 [1] https://reproducible-builds.org/specs/source-date-epoch/

Signed-off-by: Chris Lamb <lamby@debian.org>
This commit is contained in:
Chris Lamb 2017-03-15 10:36:21 +00:00 committed by Chris Lamb
parent 2f36da5201
commit cb610d54b4
8 changed files with 100 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
lib/prototypes.h
View File

@ -179,6 +179,9 @@ extern int getrange (char *range,
unsigned long *min, bool *has_min,
unsigned long *max, bool *has_max);
/* gettime.c */
extern time_t gettime ();
/* get_uid.c */
extern int get_uid (const char *uidstr, uid_t *uid);

1
libmisc/Makefile.am
View File

@ -31,6 +31,7 @@ libmisc_a_SOURCES = \
getdate.y \
getgr_nam_gid.c \
getrange.c \
gettime.c \
hushed.c \
idmapping.h \
idmapping.c \

89
libmisc/gettime.c Normal file
View File

@ -0,0 +1,89 @@
/*
* Copyright (c) 2017, Chris Lamb
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#ident "$Id$"
#include <errno.h>
#include <limits.h>
#include <stdio.h>
#include "defines.h"
#include "prototypes.h"
/*
* gettime() returns the time as the number of seconds since the Epoch
*
* Like time(), gettime() returns the time as the number of seconds since the
* Epoch, 1970-01-01 00:00:00 +0000 (UTC), except that if the SOURCE_DATE_EPOCH
* environment variable is exported it will use that instead.
*/
/*@observer@*/time_t gettime ()
{
char *endptr;
char *source_date_epoch;
time_t fallback;
unsigned long long epoch;
fallback = time (NULL);
source_date_epoch = getenv ("SOURCE_DATE_EPOCH");
if (!source_date_epoch)
return fallback;
errno = 0;
epoch = strtoull (source_date_epoch, &endptr, 10);
if ((errno == ERANGE && (epoch == ULLONG_MAX || epoch == 0))
|| (errno != 0 && epoch == 0)) {
fprintf (stderr,
_("Environment variable $SOURCE_DATE_EPOCH: strtoull: %s\n"),
strerror(errno));
} else if (endptr == source_date_epoch) {
fprintf (stderr,
_("Environment variable $SOURCE_DATE_EPOCH: No digits were found: %s\n"),
endptr);
} else if (*endptr != '\0') {
fprintf (stderr,
_("Environment variable $SOURCE_DATE_EPOCH: Trailing garbage: %s\n"),
endptr);
} else if (epoch > ULONG_MAX) {
fprintf (stderr,
_("Environment variable $SOURCE_DATE_EPOCH: value must be smaller than or equal to %lu but was found to be: %llu\n"),
ULONG_MAX, epoch);
} else if (epoch > fallback) {
fprintf (stderr,
_("Environment variable $SOURCE_DATE_EPOCH: value must be smaller than or equal to the current time (%lu) but was found to be: %llu\n"),
fallback, epoch);
} else {
/* Valid */
return (time_t)epoch;
}
return fallback;
}

2
src/chpasswd.c
View File

@ -552,7 +552,7 @@ int main (int argc, char **argv)
if (NULL != sp) {
newsp = *sp;
newsp.sp_pwdp = cp;
newsp.sp_lstchg = (long) time ((time_t *)NULL) / SCALE;
newsp.sp_lstchg = (long) gettime () / SCALE;
if (0 == newsp.sp_lstchg) {
/* Better disable aging than requiring a
* password change */

4
src/newusers.c
View File

@ -496,7 +496,7 @@ static int add_passwd (struct passwd *pwd, const char *password)
}
spent.sp_pwdp = cp;
}
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 */
@ -553,7 +553,7 @@ static int add_passwd (struct passwd *pwd, const char *password)
*/
spent.sp_pwdp = "!";
#endif
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 */
spent.sp_lstchg = -1;

2
src/passwd.c
View File

@ -668,7 +668,7 @@ static void update_shadow (void)
}
#ifndef USE_PAM
if (do_update_age) {
nsp->sp_lstchg = (long) time ((time_t *) 0) / SCALE;
nsp->sp_lstchg = (long) gettime () / SCALE;
if (0 == nsp->sp_lstchg) {
/* Better disable aging than requiring a password
* change */

2
src/useradd.c
View File

@ -828,7 +828,7 @@ static void new_spent (struct spwd *spent)
memzero (spent, sizeof *spent);
spent->sp_namp = (char *) user_name;
spent->sp_pwdp = (char *) user_pass;
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 */
spent->sp_lstchg = -1;

4
src/usermod.c
View File

@ -641,7 +641,7 @@ static void new_spent (struct spwd *spent)
spent->sp_pwdp = new_pw_passwd (spent->sp_pwdp);
if (pflg) {
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. */
@ -1673,7 +1673,7 @@ static void usr_update (void)
spent.sp_pwdp = xstrdup (pwent.pw_passwd);
pwent.pw_passwd = xstrdup (SHADOW_PASSWD_STRING);
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 */