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.
If ptr->line == NULL for an entry, the first cycle will exit,
but the second one will happily write past entries buffer.
We actually do not want to exit the first cycle prematurely
on ptr->line == NULL.
Signed-off-by: Tomas Mraz <tmraz@fedoraproject.org>
* configure.in: Add configure options --enable-subordinate-ids /
--disable-subordinate-ids. Enabled by default.
* lib/prototypes.h: Include <config.h> before using its macros.
* lib/commonio.h, lib/commonio.c: Define commonio_append only when
ENABLE_SUBIDS is defined.
* lib/prototypes.h, libmisc/find_new_sub_gids.c,
libmisc/find_new_sub_uids.c: Likewise.
* lib/subordinateio.h, lib/subordinateio.c: Likewise.
* libmisc/user_busy.c: Only check if subordinate IDs are in use if
ENABLE_SUBIDS is defined.
* src/Makefile.am: Create newgidmap and newuidmap only if
ENABLE_SUBIDS is defined.
* src/newusers.c: Check for ENABLE_SUBIDS to enable support for
subordinate IDs.
* src/useradd.c: Likewise.
* src/userdel.c: Likewise.
* src/usermod.c: Likewise.
* man/Makefile.am: Install man1/newgidmap.1, man1/newuidmap.1,
man5/subgid.5, and man5/subuid.5 only if ENABLE_SUBIDS is defined.
* man/fr/Makefile.am: Install man1/newgidmap.1, man1/newuidmap.1,
man5/subgid.5, and man5/subuid.5 (not translated yet).
* man/generate_mans.mak: Add xsltproc conditionals
subids/no_subids.
* man/login.defs.d/SUB_GID_COUNT.xml: Add dependency on subids
condition.
* man/login.defs.d/SUB_UID_COUNT.xml: Likewise.
* man/usermod.8.xml: Document options for subordinate IDs and
reference subgid(5) / subuid(5) depending on the subids condition.
To support files that do not have a simple unique key implement
commonio_append to allow new entries to be added.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
libmisc/copydir.c, lib/selinux.c: Move set_selinux_file_context()
and reset_selinux_file_context() from libmisc/copydir.c to
lib/selinux.c.
* lib/commonio.c: Use set_selinux_file_context() and
reset_selinux_file_context() instead of using the existing
database SELinux context to set the context for the newly created
files.
* 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.
indicate why locking failed.
* NEWS, lib/commonio.c: Fix the sort algorithm in case of NIS. NIS
entries were dropped.
* lib/commonio.c: NIS entries can start by '+' or '-'.
libmisc/sulog.c, libmisc/hushed.c, libmisc/failure.c,
libmisc/loginprompt.c, libmisc/ttytype.c,
libmisc/pam_pass_non_interractive.c, src/userdel.c, src/login.c,
lib/commonio.c, lib/commonio.h: Fix some const issues.
* libmisc/motd.c: Avoid multi-statements lines.
* libmisc/motd.c: Support long MOTD_FILE.
* libmisc/list.c, lib/prototypes.h: Revert previous change.
dup_list and is_on_list are used with members as defined for the
group structure, and thus even if the list is not modified, the
list elements cannot be constant strings.
* libmisc/system.c: Avoid C++ comments.
* src/vipw.c: WITH_TCB cannot be tested inside a gettextized
string. Split the Usage string.
* lib/commonio.h: Re-indent.
* NEWS: Add support for TCB.
* lib/tcbfuncs.h, lib/tcbfuncs.c, lib/Makefile.am: New library to
support TCB.
* lib/prototypes, libmisc/copydir.c (remove_tree): Add boolean
parameter remove_root.
* configure.in: Add conditional WITH_TCB.
* src/userdel.c, src/usermod.c: Add support for TCB. Update call to
remove_tree().
* src/pwconv.c, src/pwunconv.c: Should not be used with TCB enabled.
* src/vipw.c: Add support for TCB. Update call to remove_tree().
* src/useradd.c: Add support for TCB. Open the shadow file outside
of open_files().
* src/chage.c: Add support for TCB.
* src/Makefile.am: Install passwd sgid shadow when TCB is enabled.
* lib/getdefs.c, man/vipw.8.xml, man/login.defs.5.xml,
man/login.defs/TCB_AUTH_GROUP.xml, man/login.defs/USE_TCB.xml,
man/login.defs/TCB_SYMLINKS.xml, man/generate_mans.mak,
man/generate_mans.deps, man/Makefile.am: New configuration
parameters: TCB_AUTH_GROUP, TCB_SYMLINKS, USE_TCB.
* lib/shadowio.c, lib/commonio.c: Add support for TCB.
with a NULL argument.
* src/useradd.c: Replace PATH_MAX by a fixed constant. The buffer
was not meant as a storage for a path.
* src/useradd.c, src/newusers.c, src/chpasswd.c: Better detection
of fgets errors. Lines shall end with a \n, unless we reached the
end of file.
* libmisc/copydir.c: Avoid PATH_MAX. Support file paths with any
length. Added readlink_malloc().
unlink() in case of failure of fopen_set_perms() or
create_backup().
* lib/commonio.c: Should the backup file be unlink'ed in case of
failure of create_backup()?
lib/pwio.c, lib/pwio.h, lib/shadowio.c, lib/shadowio.h: Added
splint annotations. The *_locate() and *_next() functions
currently return an observer. As the structure are often modified
by the caller, it could maybe be changed to exposed later. (and
non-const).
* lib/commonio.h: Include defines.h to get the definition of bool.
* lib/commonio.h: commonio_present returns a bool
* lib/commonio.c: Implement above changes.
* lib/commonio.c: add argument names in prototypes.
* lib/commonio.c: name_is_nis returns a bool.
* lib/commonio.c: nscd_need_reload is a bool.
* lib/commonio.c: Improve types (use size_t / pid_t when needed instead of int).
* lib/commonio.c: Avoid assignments in comparisons.
* lib/commonio.c: Add brackets and parenthesis.
* lib/commonio.c: Avoid implicit conversion of pointers / integers to booleans
* lib/commonio.c: The return values of utime is not checked on purpose.
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".
