Some distributions, notably Fedora, have the following order of nsswitch
modules by default:
passwd: sss files
group: sss files
The advantage of serving local users through SSSD is that the nss_sss
module has a fast mmapped-cache that speeds up NSS lookups compared to
accessing the disk an opening the files on each NSS request.
Traditionally, this has been done with the help of nscd, but using nscd
in parallel with sssd is cumbersome, as both SSSD and nscd use their own
independent caching, so using nscd in setups where sssd is also serving
users from some remote domain (LDAP, AD, ...) can result in a bit of
unpredictability.
More details about why Fedora chose to use sss before files can be found
on e.g.:
https://fedoraproject.org//wiki/Changes/SSSDCacheForLocalUsers
or:
https://docs.pagure.org/SSSD.sssd/design_pages/files_provider.html
Now, even though sssd watches the passwd and group files with the help
of inotify, there can still be a small window where someone requests a
user or a group, finds that it doesn't exist, adds the entry and checks
again. Without some support in shadow-utils that would explicitly drop
the sssd caches, the inotify watch can fire a little late, so a
combination of commands like this:
getent passwd user || useradd user; getent passwd user
can result in the second getent passwd not finding the newly added user
as the racy behaviour might still return the cached negative hit from
the first getent passwd.
This patch more or less copies the already existing support that
shadow-utils had for dropping nscd caches, except using the "sss_cache"
tool that sssd ships.
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>
passwd, shadow, group, gshadow etc. can be managed via nss -
e.g. system default accounts can be specified using nss_altfiles,
rather than in /etc/. Thus despite having default accounts, these
files can be missing on disk and thus should be opened with O_CREATE
whenever they are attempted to be opened in O_RDWR modes.
* Changelog: Update documentation of 2013-07-28 mancha entry.
* lib/prototypes.h, lib/encrypt.c: Update splint marker,
pw_encrypt can return NULL.
* lib/encrypt.c: Fix outdated statement on GNU crypt.
* src/chgpasswd.c: Improve diagnostic to user when pw_encrypt
fails and use fail_exit() instead of exit().
* src/chpasswd.c: Likewise.
* src/newusers.c: Likewise.
* src/passwd.c: Likewise when new password is encrypted.
* src/newgrp.c: Improve diagnostic to user and syslog when
pw_encrypt fails. Do not apply 1s penalty as this is not an
invalid password issue.
* src/passwd.c: Likewise when password is checked.
a salt that violates specs. On Linux, crypt() also fails with
DES/MD5 salts in FIPS140 mode. Rather than exit() on NULL returns
we send them back to the caller for appropriate handling.
* lib/commonio.c: Avoid multiple statements per line.
* lib/commonio.c: Ignore fclose return value when the file was
open read only or was not changed, or if an error is already
reported.
instead of an int.
* libmisc/obscure.c, libmisc/tz.c, src/passwd.c, lib/encrypt.c,
libmisc/copydir.c, lib/prototypes.h: Add splint annotations.
* libmisc/tz.c: Fix some const issues.
* libmisc/tz.c: Avoid multi-statements lines.
* libmisc/tz.c: Add brackets.
* libmisc/copydir.c: Do not check *printf/*puts return value.
* libmisc/copydir.c: Fail if we cannot set or reset the SELinux
fscreate context.
* libmisc/copydir.c: Use xmalloc instead of malloc.
* libmisc/copydir.c: Do not check lutimes return value
* src/vipw.c: Avoid implicit conversion of integer to boolean.
* src/su.c (iswheel): Return a bool instead of an int.
* src/passwd.c: Remove insert_crypt_passwd(). Use xstrdup instead.
* src/passwd.c: Return constant strings when sufficient.
* src/passwd.c: Do not check *printf/*puts return value.
* src/passwd.c: Avoid implicit conversion of character to boolean.
* src/passwd.c: Do not check sleep return value.
* src/sulogin.c: Do not check *printf/*puts return value.
* lib/encrypt.c: Do not check fprintf return value.
* src/login_nopam.c: Limit the scope of variables end, lineno, i,
str_len.
* src/logoutd.c: Limit the scope of variable c.
* src/vipw.c: Re-indent.
* src/vipw.c: Close the file after the creation of the backup.
* src/useradd.c (set_default): Close input file on failure.
* src/useradd.c: Limit the scope of variables spool, file, fd, gr,
gid, mode.
* src/passwd.c: Limit the scope of variables last and ok.
* src/chage.c: Fix typo (non breaking space).
* src/login.c: Limit the scope of variables erasechar killchar, c,
failed.
* src/groups.c: Limit the scope of variable ngroups, pri_grp, i.
* src/id.c: Limit the scope of variable i.
src/chpasswd.c, src/groupmems.c, src/usermod.c, src/chgpasswd.c,
src/vipw.c, src/su.c, src/useradd.c, src/groupmod.c, src/passwd.c,
src/groupadd.c, src/chage.c, src/faillog.c, src/chsh.c: Use
booleans for tests.
* src/userdel.c, src/gpasswd.c, src/groupmems.c, src/usermod.c,
src/groupmod.c, src/passwd.c: Use a break even after usage().
src/newusers.c, src/chpasswd.c, src/groupmems.c, src/usermod.c,
src/chgpasswd.c, src/vipw.c, src/su.c, src/useradd.c,
src/groupmod.c, src/passwd.c, src/groupadd.c, src/chage.c,
src/faillog.c, src/chsh.c: If someone uses the -h/--help options,
the usage should not go to stderr nor should the utility exit with
non-zero status. All of the shadow utils do just this
unfortunately, so convert them over to sanity.
* man/groupmems.8.xml, man/gpasswd.1.xml: Added option -h/--help.
src/passwd.c, src/pwck.c, src/pwconv.c, src/useradd.c,
src/usermod.c: On Jan 01, 1970, do not set the sp_lstchg field to
0 (which means that the password shall be changed during the next
login), but use -1 (password aging disabled).
* src/passwd.c: Do not check sp_min if sp_lstchg is null or -1.
src/newusers.c, src/pwconv.c, src/chpasswd.c, src/logoutd.c,
src/chfn.c, src/groupmems.c, src/usermod.c, src/pwunconv.c,
src/expiry.c, src/groupdel.c, src/chgpasswd.c, src/useradd.c,
src/su.c, src/groupmod.c, src/passwd.c, src/pwck.c,
src/groupadd.c, src/chage.c, src/login.c, src/grpconv.c,
src/groups.c, src/grpunconv.c, src/chsh.c: Prog is now global (not
static to the file) so that it can be used by the helper functions
of libmisc.
* lib/prototypes.h: Added extern char *Prog.
* libmisc/find_new_gid.c, libmisc/find_new_uid.c: Indicate the
program name with the warning.
* src/chage.c, src/chfn.c, src/chgpasswd.c, src/chpasswd.c,
src/chsh.c, src/gpasswd.c, src/groupadd.c, src/groupmems.c,
src/groupmod.c, src/grpck.c, src/grpconv.c, src/grpunconv.c,
src/passwd.c, src/pwck.c, src/pwconv.c, src/pwunconv.c,
src/useradd.c, src/userdel.c, src/usermod.c: Harmonize the error
message sent to stderr in case of *_update () failure.
* src/chage.c, src/chsh.c, src/groupadd.c, src/passwd.c: Do not
log to syslog when pw_update() or spw_update() fail.
* src/newusers.c: Do not log specific error message to stderr when
sgr_update() fails.
* src/pwconv.c: Remove duplicated definition of Prog.
src/newgrp.c, src/passwd.c, src/su.c: Use the same stderr and
syslog warnings when the username cannot be determined.
* src/newgrp.c: Reuse the same stderr message for groups which do
not exist in the system.
* src/grpconv.c, src/grpunconv.c, src/pwconv.c, src/pwunconv.c,
src/vipw.c: Open syslog with the right identification name.
* src/vipw.c: Log unlock errors to syslog.
* src/vipw.c: Log edits to syslog.
* src/chage.c, src/chfn.c, src/chsh.c, src/gpasswd.c,
src/groupadd.c, src/groupdel.c, src/groupmod.c, src/grpconv.c,
src/grpunconv.c, src/passwd.c, src/pwck.c, src/pwunconv.c,
src/useradd.c, src/usermod.c: Harmonize the syslog levels. Failure
to close or unlock are errors. Failure to open files are warnings.
src/gpasswd.c, src/groupadd.c, src/groupdel.c, src/groupmems.c,
src/groupmod.c, src/grpck.c, src/grpconv.c, src/grpunconv.c,
src/newusers.c, src/passwd.c, src/pwck.c, src/pwconv.c,
src/pwunconv.c, src/useradd.c, src/userdel.c, src/usermod.c: In
case of a lock failure, indicate to the user that she can try
again later. Do not log to syslog.
the --lock an --unlock options do not lock or unlock the user
account anymore. They only lock or unlock the user's password.
* man/passwd.1.xml: Document above change. Document how an account
can be locked and what a password lock means.
lib/sgroupio.c, lib/sgroupio.h, lib/shadowio.c, lib/shadowio.h:
Added *_dbname() functions to retrieve the name of the databases.
* lib/groupio.c, lib/groupio.h, lib/pwio.c, lib/pwio.h,
lib/sgroupio.c, lib/sgroupio.h, lib/shadowio.c, lib/shadowio.h:
*_name() functions renamed *setname().
* src/grpck.c, src/pwck.c: Likewise.
* lib/groupio.h, lib/pwio.h, lib/sgroupio.h, lib/shadowio.h: Added
the name of the arguments to the prototypes.
* src/chage, src/chfn.c, src/chgpasswd.c, src/chpasswd.c,
src/chsh.c, src/gpasswd.c, src/groupadd.c, src/groupdel.c,
src/groupmod.c, src/grpck.c, src/grpconv.c, src/grpunconv.c,
src/newusers.c, src/passwd.c, src/pwck.c, src/pwconv.c,
src/pwunconv.c, src/useradd.c, src/userdel.c, src/usermod.c:
Harmonize the erro & syslog messages in case of failure of the
*_lock(), *_open(), *_close(), *_unlock(), *_remove() functions.
* src/chgpasswd.c, src/chpasswd.c, src/usermod.c: Avoid
capitalized messages.
* src/chpasswd.c, src/useradd.c, src/usermod.c: Harmonize messages
in case of inexistent entries.
* src/usermod.c: Harmonize messages in case of already existing
entries.
* src/newusers.c, src/useradd.c: Simplify PAM error handling.
* src/useradd.c: Report failures to unlock files (stderr, syslog,
and audit). But do not fail (continue).
* src/useradd.c (open_files): Do not report to syslog & audit
failures to lock or open the databases. This might be harmless,
and the logs were not already informed that a change was
requested.
* src/usermod.c: It's not the account which is unlocked, but its
password.
src/groupmod.c, src/grpck.c, src/login.c, src/logoutd.c,
src/newgrp.c, src/newusers.c, src/passwd.c, src/pwck.c,
src/suauth.c, src/useradd.c, src/userdel.c, src/usermod.c,
src/vipw.c: Complete the switch from the `' quotation style to ''.
Do it also in SYSLOG messages. Quote some parameters. All this
permits to merge some messages.
* src/passwd.c: Avoid assignments in comparisons.
* src/passwd.c: Add brackets and parenthesis.
* src/passwd.c: Avoid implicit conversion of pointers / integers /
chars to booleans.
* src/passwd.c: Move the "context_t c" declaration at the
beginning check_selinux_access.
* src/passwd.c: Ignore return value of setlocale(),
bindtextdomain(), and textdomain().
* libmisc/audit_help.c: Include prototypes.h to get the prototype
of audit_help_open.
* libmisc/salt.c: Use booleans instead of negating integers.
* src/passwd.c: Declare the check_selinux_access prototype and
avoid name clashes (change_user -> changed_user; change_uid ->
changed_uid; access -> requested_access)
Files with no license use the default 3-clauses BSD license. The copyright
were mostly not recorded; they were updated according to the Changelog.
"Julianne Frances Haugh and contributors" changed to "copyright holders
and contributors".
endpwend() sequences (ditto for getgrent(), getspent(), and
getsgent()). The only real (minor) issue was in login, which kept
the passwd file open.
* libmisc/entry.c: Remove unneeded setspent() and endspent() (only
getspnam is called in the middle).
* libmisc/find_new_ids.c: Make sure to close the password and
group files with endpwent() and endgrent().
* libmisc/pwdcheck.c: Remove unneeded endspent() (only getspnam()
is called before).
* src/lastlog.c, src/passwd.c, src/groupmod.c, src/faillog.c,
src/groups.c: Make sure to close
the password file with endpwent().
* src/login.c: Remove unneeded setpwent() (only xgetpwnam is
called before).
* src/login.c, src/newgrp.c: Fix typos in comments.
src/chfn.c, src/passwd.c, src/chage.c, src/login.c, src/sulogin.c,
src/chsh.c: Fix call to puts (remove end of line, or use fputs).
* po/*.po: Unfuzzy PO files according to above change.
Jakub Hrozek
Chris Lamb
Dimitri John Ledkov
Nicolas François
mancha
nekral-guest