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.
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.
src/chsh.c, src/groupadd.c, src/groupdel.c, src/groupmems.c,
src/groupmod.c, src/newusers.c, src/useradd.c, src/userdel.c,
src/usermod.c: Provide the PAM error
message instead of our own, and log error to syslog.
* src/groupmems.c: Exit with exit rather than fail_exit in usage().
* src/newusers.c: Check the number of arguments.
* src/newusers.c: Do not create the home directory when it is not
changed.
* src/useradd.c: Set the group password to "!" rather "x" if there
are no gshadow file.
audit after the potential chroot.
* src/groupadd.c: Check atexit failures.
* src/groupadd.c: Return E_SUCCESS instead of exit'ing at the end
of main().
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.
messages not related to an account.
* lib/prototypes.h, libmisc/cleanup.c, libmisc/cleanup_group.c,
libmisc/cleanup_user.c, libmisc/Makefile.am: Added stack of
cleanup functions to be executed on exit.
* NEWS, src/groupadd.c, src/groupdel.c, src/groupmod.c: Only
report success to audit and syslog when the changes are committed
to the system. Do not log failure for on-memory changes to audit
or syslog. Make sure failures and inconsistencies will be reported
in case of unexpected failures (e.g. malloc failures). Only
specify an audit message if it is not implicitly implied by the
type argument. Removed fail_exit (replaced by atexit(do_cleanups)).
* src/userdel.c, src/newusers.c, src/chpasswd.c, src/chfn.c,
src/groupmems.c, src/usermod.c, src/groupdel.c, src/chgpasswd.c,
src/useradd.c, src/groupmod.c, src/groupadd.c, src/chage.c,
src/chsh.c: If the username cannot be determined, report it as
such (not a PAM authentication failure).
enable/disable the usage of PAM to authenticate the callers of
account management tools: chage, chgpasswd, chpasswd, groupadd,
groupdel, groupmod, useradd, userdel, usermod.
* src/Makefile.am: Do not link the above tools with libpam if
account-tools-setuid is disabled.
* src/userdel.c, src/newusers.c, src/chpasswd.c, src/usermod.c,
src/groupdel.c, src/chgpasswd.c, src/useradd.c, src/groupmod.c,
src/groupadd.c, src/chage.c: Implement ACCT_TOOLS_SETUID
(--enable-account-tools-setuid).
* etc/pam.d/Makefile.am: Install the pam service file for the
above tools only when needed.
* src/useradd.c, src/userdel.c, src/usermod.c: It is no more
needed to initialize retval to PAM_SUCCESS.
src/groupmems.c, src/usermod.c, src/groupdel.c, src/chgpasswd.c,
src/useradd.c, src/groupmod.c, src/groupadd.c, src/chage.c,
src/chsh.c: Simplify the PAM error handling. Do not keep the pamh
handle, but terminate the PAM transaction as soon as possible if
there are no PAM session opened.
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.
shadow_audit_result for the result argument of audit_logger().
This permits stronger type checking and a better readability of
the results (SHADOW_AUDIT_FAILURE/SHADOW_AUDIT_SUCCESS constants).
* src/groupadd.c, src/groupdel.c, src/useradd.c, src/userdel.c:
Use the SHADOW_AUDIT_FAILURE/SHADOW_AUDIT_SUCCESS results instead
of 0 or 1 in audit_logger().
changes have started to be reported to syslog.
* src/userdel.c: Fix some result parameters sent to
audit_logger().
* NEWS: Following changes from a patch contributed by Steve Grubb
<sgrubb@redhat.com>
* src/groupadd.c: Log to audit with type AUDIT_ADD_GROUP instead
of AUDIT_USER_CHAUTHTOK.
* src/groupdel.c: Log to audit with type AUDIT_DEL_GROUP instead
of AUDIT_USER_CHAUTHTOK.
* src/useradd.c: Log to audit with type AUDIT_ADD_USER /
AUDIT_ADD_GROUP / AUDIT_USYS_CONFIG instead of
AUDIT_USER_CHAUTHTOK.
* src/useradd.c: Add missing logs to audit.
* src/userdel.c: Log to audit with type AUDIT_DEL_USER /
AUDIT_DEL_GROUP instead of AUDIT_USER_CHAUTHTOK.
* src/userdel.c: Add missing logs to audit.
* 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/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/groupadd.c, src/groupdel.c, src/groupmems.c, src/groupmod.c,
src/grpconv.c, src/grpunconv.c, src/newusers.c, src/pwconv.c,
src/pwunconv.c, src/useradd.c, src/userdel.c: Harmonize the name
of the variables keeping the lock status, to match the shadow
library prefixes.
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.
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.
group or gshadow files were previously locked.
* src/groupadd.c: Make sure failures are reported to syslog/audit
after the change is mentioned.
* src/groupmod.c: Add logging to syslog & audit on lock/unlock
failures.
* src/groupmod.c: Make sure issues are reported to syslog or audit
after the change is mentioned.
* src/groupdel.c: Only call gr_unlock() and sgr_unlock() in the
group or gshadow files were previously locked.
* src/groupdel.c: Simplify the handling of PAM errors.
integers.
* src/groupadd.c: Add brackets and parenthesis.
* src/groupadd.c: Avoid implicit conversion of pointers / integers
/ chars to booleans.
* src/groupadd.c: Ignore return value of setlocale(),
bindtextdomain(), and textdomain().
* src/groupadd.c: Ignore the return value of pam_end() before
exiting.
check_user_name) renamed to is_valid_user_name (resp.
is_valid_group_name). is_valid_user_name and is_valid_group_name
return a bool.
* src/grpck.c, src/newusers.c, src/usermod.c, src/useradd.c,
src/groupmod.c, src/pwck.c, src/groupadd.c: Use is_valid_user_name
and is_valid_group_name, following above change.
* libmisc/chkname.c: Avoid implicit conversion of chars to
booleans. Add brackets and parenthesis.
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".
