[Pkg-shadow-devel] Bug#857803: Bug#857803: shadow: Make the sp_lstchg shadow field reproducible.

Serge E. Hallyn serge at hallyn.com
Fri Apr 7 21:40:23 UTC 2017


Quoting Chris Lamb (lamby at debian.org):
> Package: shadow
> Severity: wishlist
> Version: 1:4.4-4
> Tags: patch
> User: reproducible-builds at lists.alioth.debian.org
> Usertags: toolchain
> X-Debbugs-Cc: reproducible-bugs at lists.alioth.debian.org
> 
> Hi,
> 
> Attached is the following:
> 
>   commit 2dd84b0ee31e44dc51cba7b7cdc8657bf9ff0a31
>   Author: Chris Lamb <lamby at debian.org>
>   Date:   Wed Mar 15 11:35:35 2017 +0100
>   
>       Make the sp_lstchg shadow field reproducible.
>       
>       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 available.
>       
>        [0] https://reproducible-builds.org/
>        [1] https://reproducible-builds.org/specs/source-date-epoch/
>       
>       Signed-off-by: Chris Lamb <lamby at debian.org>
>   
>    lib/prototypes.h    |  3 ++
>    libmisc/Makefile.am |  1 +
>    libmisc/gettime.c   | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>    src/chpasswd.c      |  2 +-
>    src/newusers.c      |  4 +--
>    src/passwd.c        |  2 +-
>    src/useradd.c       |  2 +-
>    src/usermod.c       |  4 +--
>    8 files changed, 97 insertions(+), 7 deletions(-)
> 
> 
> Regards,

Hi,

looks ok to me, although, would it be better to fall back to time(NULL)
if the env variable is invalid?

Do you want to submit this as a patch to upstream at
github.com/shadow-maint/shadow ?

-serge

> 
> -- 
>       ,''`.
>      : :'  :     Chris Lamb
>      `. `'`      lamby at debian.org / chris-lamb.co.uk
>        `-

> >From 2dd84b0ee31e44dc51cba7b7cdc8657bf9ff0a31 Mon Sep 17 00:00:00 2001
> From: Chris Lamb <lamby at debian.org>
> Date: Wed, 15 Mar 2017 11:35:35 +0100
> Subject: [PATCH] Make the sp_lstchg shadow field reproducible.
> 
> 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 available.
> 
>  [0] https://reproducible-builds.org/
>  [1] https://reproducible-builds.org/specs/source-date-epoch/
> 
> Signed-off-by: Chris Lamb <lamby at debian.org>
> ---
>  lib/prototypes.h    |  3 ++
>  libmisc/Makefile.am |  1 +
>  libmisc/gettime.c   | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/chpasswd.c      |  2 +-
>  src/newusers.c      |  4 +--
>  src/passwd.c        |  2 +-
>  src/useradd.c       |  2 +-
>  src/usermod.c       |  4 +--
>  8 files changed, 97 insertions(+), 7 deletions(-)
>  create mode 100644 libmisc/gettime.c
> 
> diff --git a/lib/prototypes.h b/lib/prototypes.h
> index 7aaf1a6..4808d5d 100644
> --- a/lib/prototypes.h
> +++ b/lib/prototypes.h
> @@ -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);
>  
> diff --git a/libmisc/Makefile.am b/libmisc/Makefile.am
> index 76f3c05..e691dac 100644
> --- a/libmisc/Makefile.am
> +++ b/libmisc/Makefile.am
> @@ -31,6 +31,7 @@ libmisc_a_SOURCES = \
>  	getdate.y \
>  	getgr_nam_gid.c \
>  	getrange.c \
> +	gettime.c \
>  	hushed.c \
>  	idmapping.h \
>  	idmapping.c \
> diff --git a/libmisc/gettime.c b/libmisc/gettime.c
> new file mode 100644
> index 0000000..b0c539b
> --- /dev/null
> +++ b/libmisc/gettime.c
> @@ -0,0 +1,86 @@
> +/*
> + * 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;
> +	unsigned long long epoch;
> +
> +	source_date_epoch = getenv ("SOURCE_DATE_EPOCH");
> +	if (!source_date_epoch)
> +		return time (NULL);
> +
> +	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));
> +		exit(EXIT_FAILURE);
> +	}
> +	if (endptr == source_date_epoch) {
> +		fprintf (stderr,
> +		         _("Environment variable $SOURCE_DATE_EPOCH: No digits were found: %s\n"),
> +			 endptr);
> +		exit(EXIT_FAILURE);
> +	}
> +	if (*endptr != '\0') {
> +		fprintf (stderr,
> +		         _("Environment variable $SOURCE_DATE_EPOCH: Trailing garbage: %s\n"),
> +			 endptr);
> +		exit(EXIT_FAILURE);
> +	}
> +	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);
> +		exit(EXIT_FAILURE);
> +	}
> +
> +	return (time_t)epoch;
> +}
> diff --git a/src/chpasswd.c b/src/chpasswd.c
> index 21008f5..f985672 100644
> --- a/src/chpasswd.c
> +++ b/src/chpasswd.c
> @@ -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 */
> diff --git a/src/newusers.c b/src/newusers.c
> index 724cbb4..2b0c693 100644
> --- a/src/newusers.c
> +++ b/src/newusers.c
> @@ -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;
> diff --git a/src/passwd.c b/src/passwd.c
> index 1191111..3af3e65 100644
> --- a/src/passwd.c
> +++ b/src/passwd.c
> @@ -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 */
> diff --git a/src/useradd.c b/src/useradd.c
> index fefa234..d7bde8f 100644
> --- a/src/useradd.c
> +++ b/src/useradd.c
> @@ -825,7 +825,7 @@ 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;
> diff --git a/src/usermod.c b/src/usermod.c
> index 687487d..db8c0a8 100644
> --- a/src/usermod.c
> +++ b/src/usermod.c
> @@ -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 */
> -- 
> 2.11.0
> 

> _______________________________________________
> Pkg-shadow-devel mailing list
> Pkg-shadow-devel at lists.alioth.debian.org
> http://lists.alioth.debian.org/cgi-bin/mailman/listinfo/pkg-shadow-devel



More information about the Pkg-shadow-devel mailing list