As autoconf documentation says, this macro is obsolescent, as no
current systems have the bug in S_ISDIR, S_ISREG, etc..
The affected systems were Tektronix UTekV, Amdahl UTS, and
Motorola System V/88.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
GNU autoconf documentation marks this macro as obsolescent, as
current systems are compatible with POSIX.
Simplify code to unconditionally include <sys/wait.h>, and don't
redefine WIFEXITSTATUS() and WIFEXITED(), since they are mandated
by POSIX.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
POSIX.1-2001 defines 'struct dirent' in <dirent.h>. It replaces
the old 'struct direct' found in BSDs. All of the systems that I
checked (including FreeBSD, NetBSD, and OpenBSD), now provide
<dirent.h> with 'struct dirent', as mandated by POSIX.
Since autoconf first checks <dirent.h> and only if it's missing it
checks other header files, it's clear that it will always find
<dirent.h>, so let's simplify.
GNU autoconf documentation declares this macro as obsolescent, and
acknowledges that all current systems with directory libraries
have <dirent.h>:
<https://www.gnu.org/software/autoconf/manual/autoconf-2.70/html_node/Particular-Headers.html>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Compilers are allowed to and do optimize memset(3) calls away for
pointers not accessed in the future. Since the memzero wrappers purpose
is exactly to unconditionally override memory (e.g. for stored
passwords) do not implement via regular memset(3), but via either
memset_s(3), explicit_bzero(3) or a hand written implementation using
volatile pointers.
See https://wiki.sei.cmu.edu/confluence/display/c/MSC06-C.+Beware+of+compiler+optimizations
run_part() and run_parts() do not modify their directory, name and
action arguments.
Also include the header in the implementation to provide the prototypes.
useradd.c:2495:59: warning: cast discards ‘const’ qualifier from pointer target type [-Wcast-qual]
2495 | if (run_parts ("/etc/shadow-maint/useradd-pre.d", (char*)user_name,
| ^
useradd.c:2495:24: warning: passing argument 1 of ‘run_parts’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
2495 | if (run_parts ("/etc/shadow-maint/useradd-pre.d", (char*)user_name,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from useradd.c:45:
../lib/run_part.h:2:22: note: expected ‘char *’ but argument is of type ‘const char *’
2 | int run_parts (char *directory, char *name, char *action);
| ~~~~~~^~~~~~~~~
useradd.c:2496:25: warning: passing argument 3 of ‘run_parts’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
2496 | "useradd")) {
| ^~~~~~~~~
nss_init() does not modify its path argument, thus declare it const.
Also drop superfluous prototype.
nss.c:54:31: warning: assignment discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
54 | nsswitch_path = NSSWITCH;
| ^
Function declarations with no argument declare functions taking an
arbitrary number of arguments. Use the special type void to declare
functions taking no argument.
It wasn't being used at all. Let's remove it.
Use isdigit(3) directly in comments that referenced it.
Also, in those comments, remove an outdated reference to the fact
that ISDIGIT_LOCALE(c) might evaluate its argument more than once,
which could be true a few commits ago, until
IN_CTYPE_DEFINITION(c) was removed. Previously, the definition
for ISDIGIT_LOCALE(c) was:
#if defined (STDC_HEADERS) || (!defined (isascii) && !defined (HAVE_ISASCII))
# define IN_CTYPE_DOMAIN(c) 1
#else
# define IN_CTYPE_DOMAIN(c) isascii(c)
#endif
#define ISDIGIT_LOCALE(c) (IN_CTYPE_DOMAIN (c) && isdigit (c))
Which could evaluate 'c' twice on pre-C89 systems (which I hope
don't exist nowadays).
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
The recent removal of STDC_HEADERS made IN_CTYPE_DOMAIN be defined
to 1 unconditionally. Remove the now unnecessary definition, and
propagate its truthness to expressions where it was used.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
We're in 2021. C89 is everywhere; in fact, there are many other
assumptions in the code that wouldn't probably hold on
pre-standard C environments. Let's simplify and assume that C89
is available.
The specific assumptions are that:
- <string.h>, and <stdlib.h> are available
- strchr(3), strrchr(3), and strtok(3) are available
- isalpha(3), isspace(3), isdigit(3), and isupper(3) are available
I think we can safely assume we have all of those.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
memset(3) has been in standard C since C89. It is also in
POSIX.1-2001, in SVr4, and in 4.3BSD (see memset(3) and memset(3p)).
We can assume that this function is always available.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
memcpy(3) has been in standard C since C89. It is also in
POSIX.1-2001, in SVr4, and in 4.3BSD (see memcpy(3) and memcpy(3p)).
We can assume that this function is always available.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
PARAMETERS:
According to the C2x charter, I reordered the parameters 'size'
and 'buf' from previously existing date_to_str() definitions.
C2x charter:
> 15. Application Programming Interfaces (APIs) should be
> self-documenting when possible. In particular, the order of
> parameters in function declarations should be arranged such that
> the size of an array appears before the array. The purpose is to
> allow Variable-Length Array (VLA) notation to be used. This not
> only makes the code's purpose clearer to human readers, but also
> makes static analysis easier. Any new APIs added to the Standard
> should take this into consideration.
I used 'long' for the date parameter, as some uses of the function
need to pass a negative value meaning "never".
FUNCTION BODY:
I didn't check '#ifdef HAVE_STRFTIME', which old definitions did,
since strftime(3) is guaranteed by the C89 standard, and all of
the conversion specifiers that we use are also specified by that
standard, so we don't need any extensions at all.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
The build was failing with duplicate symbol errors with -fno-common.
This is the default in GCC 10 and later, and explicitly enabled in some
distributions to catch problems like this. There were two causes:
- Prog and shadow_logfd were defined in a header file that was included
in multiple other files. Fix this by defining them once in
shadowlog.c, and having extern declarations in the header.
- Most of the tools (except id/nologin) also define a Prog variable,
which is not intended to alias the one in the library. Fix
this by renaming Prog in the library to shadow_progname, which also
matches the new accessor functions for it.
Add an additional NULL check condition in spw_free() and pw_free() to
avoid freeing an already empty pointer.
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
During shadowtcb_move() the directory is temporarily changed to be
owned by root:root with permissions 0700. After the change is done,
the ownership and permissions were supposed to be restored. The
call for chown() was there, but the chmod() call was missing. This
resulted in the broken TCB functionality. The added chmod() fixes
the issue.
Close the selabel handle to update the file_context. This means that the
file_context will be remmaped and used by selabel_lookup() to return
the appropriate context to label the home folder.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1993081
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
There's a better way to do this, and I hope to clean that up,
but this fixes out of tree builds for me right now.
Closes#386
Signed-off-by: Serge Hallyn <serge@hallyn.com>
The functions crypt(3), crypt_gensalt(3), and their
feature test macros may be defined in there.
Signed-off-by: Björn Esser <besser82@fedoraproject.org>
Error: RESOURCE_LEAK (CWE-772): [#def1]
shadow-4.8.1/lib/commonio.c:320: alloc_fn: Storage is returned from allocation function "fopen_set_perms".
shadow-4.8.1/lib/commonio.c:320: var_assign: Assigning: "bkfp" = storage returned from "fopen_set_perms(backup, "w", &sb)".
shadow-4.8.1/lib/commonio.c:329: noescape: Resource "bkfp" is not freed or pointed-to in "putc".
shadow-4.8.1/lib/commonio.c:334: noescape: Resource "bkfp" is not freed or pointed-to in "fflush".
shadow-4.8.1/lib/commonio.c:339: noescape: Resource "bkfp" is not freed or pointed-to in "fileno".
shadow-4.8.1/lib/commonio.c:342: leaked_storage: Variable "bkfp" going out of scope leaks the storage it points to.
340| || (fclose (bkfp) != 0)) {
341| /* FIXME: unlink the backup file? */
342|-> return -1;
343| }
344|
Error: RESOURCE_LEAK (CWE-772): [#def2]
shadow-4.8.1/libmisc/addgrps.c:69: alloc_fn: Storage is returned from allocation function "malloc".
shadow-4.8.1/libmisc/addgrps.c:69: var_assign: Assigning: "grouplist" = storage returned from "malloc(i * 4UL)".
shadow-4.8.1/libmisc/addgrps.c:73: noescape: Resource "grouplist" is not freed or pointed-to in "getgroups". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/libmisc/addgrps.c:126: leaked_storage: Variable "grouplist" going out of scope leaks the storage it points to.
124| }
125|
126|-> return 0;
127| }
128| #else /* HAVE_SETGROUPS && !USE_PAM */
Error: RESOURCE_LEAK (CWE-772): [#def3]
shadow-4.8.1/libmisc/chowntty.c:62: alloc_fn: Storage is returned from allocation function "getgr_nam_gid".
shadow-4.8.1/libmisc/chowntty.c:62: var_assign: Assigning: "grent" = storage returned from "getgr_nam_gid(getdef_str("TTYGROUP"))".
shadow-4.8.1/libmisc/chowntty.c:98: leaked_storage: Variable "grent" going out of scope leaks the storage it points to.
96| */
97| #endif
98|-> }
99|
Error: RESOURCE_LEAK (CWE-772): [#def4]
shadow-4.8.1/libmisc/copydir.c:742: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/libmisc/copydir.c:742: var_assign: Assigning: "ifd" = handle returned from "open(src, 0)".
shadow-4.8.1/libmisc/copydir.c:748: leaked_handle: Handle variable "ifd" going out of scope leaks the handle.
746| #ifdef WITH_SELINUX
747| if (set_selinux_file_context (dst, NULL) != 0) {
748|-> return -1;
749| }
750| #endif /* WITH_SELINUX */
Error: RESOURCE_LEAK (CWE-772): [#def5]
shadow-4.8.1/libmisc/copydir.c:751: open_fn: Returning handle opened by "open". [Note: The source code implementation of the function has been overridden by a user model.]
shadow-4.8.1/libmisc/copydir.c:751: var_assign: Assigning: "ofd" = handle returned from "open(dst, 577, statp->st_mode & 0xfffU)".
shadow-4.8.1/libmisc/copydir.c:752: noescape: Resource "ofd" is not freed or pointed-to in "fchown_if_needed".
shadow-4.8.1/libmisc/copydir.c:775: leaked_handle: Handle variable "ofd" going out of scope leaks the handle.
773| ) {
774| (void) close (ifd);
775|-> return -1;
776| }
777|
Error: RESOURCE_LEAK (CWE-772): [#def7]
shadow-4.8.1/libmisc/idmapping.c:188: alloc_fn: Storage is returned from allocation function "xmalloc".
shadow-4.8.1/libmisc/idmapping.c:188: var_assign: Assigning: "buf" = storage returned from "xmalloc(bufsize)".
shadow-4.8.1/libmisc/idmapping.c:188: var_assign: Assigning: "pos" = "buf".
shadow-4.8.1/libmisc/idmapping.c:213: noescape: Resource "buf" is not freed or pointed-to in "write".
shadow-4.8.1/libmisc/idmapping.c:219: leaked_storage: Variable "pos" going out of scope leaks the storage it points to.
shadow-4.8.1/libmisc/idmapping.c:219: leaked_storage: Variable "buf" going out of scope leaks the storage it points to.
217| }
218| close(fd);
219|-> }
Error: RESOURCE_LEAK (CWE-772): [#def8]
shadow-4.8.1/libmisc/list.c:211: alloc_fn: Storage is returned from allocation function "xstrdup".
shadow-4.8.1/libmisc/list.c:211: var_assign: Assigning: "members" = storage returned from "xstrdup(comma)".
shadow-4.8.1/libmisc/list.c:217: var_assign: Assigning: "cp" = "members".
shadow-4.8.1/libmisc/list.c:218: noescape: Resource "cp" is not freed or pointed-to in "strchr".
shadow-4.8.1/libmisc/list.c:244: leaked_storage: Variable "cp" going out of scope leaks the storage it points to.
shadow-4.8.1/libmisc/list.c:244: leaked_storage: Variable "members" going out of scope leaks the storage it points to.
242| if ('\0' == *members) {
243| *array = (char *) 0;
244|-> return array;
245| }
246|
Error: RESOURCE_LEAK (CWE-772): [#def11]
shadow-4.8.1/libmisc/myname.c:61: alloc_fn: Storage is returned from allocation function "xgetpwnam".
shadow-4.8.1/libmisc/myname.c:61: var_assign: Assigning: "pw" = storage returned from "xgetpwnam(cp)".
shadow-4.8.1/libmisc/myname.c:67: leaked_storage: Variable "pw" going out of scope leaks the storage it points to.
65| }
66|
67|-> return xgetpwuid (ruid);
68| }
69|
Error: RESOURCE_LEAK (CWE-772): [#def12]
shadow-4.8.1/libmisc/user_busy.c:260: alloc_fn: Storage is returned from allocation function "opendir".
shadow-4.8.1/libmisc/user_busy.c:260: var_assign: Assigning: "task_dir" = storage returned from "opendir(task_path)".
shadow-4.8.1/libmisc/user_busy.c:262: noescape: Resource "task_dir" is not freed or pointed-to in "readdir".
shadow-4.8.1/libmisc/user_busy.c:278: leaked_storage: Variable "task_dir" going out of scope leaks the storage it points to.
276| _("%s: user %s is currently used by process %d\n"),
277| Prog, name, pid);
278|-> return 1;
279| }
280| }
Error: RESOURCE_LEAK (CWE-772): [#def20]
shadow-4.8.1/src/newgrp.c:162: alloc_fn: Storage is returned from allocation function "xgetspnam".
shadow-4.8.1/src/newgrp.c:162: var_assign: Assigning: "spwd" = storage returned from "xgetspnam(pwd->pw_name)".
shadow-4.8.1/src/newgrp.c:234: leaked_storage: Variable "spwd" going out of scope leaks the storage it points to.
232| }
233|
234|-> return;
235|
236| failure:
Error: RESOURCE_LEAK (CWE-772): [#def21]
shadow-4.8.1/src/passwd.c:530: alloc_fn: Storage is returned from allocation function "xstrdup".
shadow-4.8.1/src/passwd.c:530: var_assign: Assigning: "cp" = storage returned from "xstrdup(crypt_passwd)".
shadow-4.8.1/src/passwd.c:551: noescape: Resource "cp" is not freed or pointed-to in "strlen".
shadow-4.8.1/src/passwd.c:554: noescape: Resource "cp" is not freed or pointed-to in "strcat". [Note: The source code implementation of the function has been overridden by a builtin model.]
shadow-4.8.1/src/passwd.c:555: overwrite_var: Overwriting "cp" in "cp = newpw" leaks the storage that "cp" points to.
553| strcpy (newpw, "!");
554| strcat (newpw, cp);
555|-> cp = newpw;
556| }
557| return cp;
Closes#331
1. drop 'has_any_range' nss method as it is not useful
2. do not try to create a subid range in newusers when using nss for
subids, since that's not possible.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
(cherry picked from commit 88a434adbdcf4a8640793fd58bcd2ba77598349d)
Following alexey-tikhonov's suggestion.
Since we've dropped the 'owner' field in the data returned for
get_subid_ranges, we can just return a single allocated array of
simple structs. This means we can return a ** instead of ***, and
we can get rid of the subid_free_ranges() helper, since the caller
can just free() the returned data.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Closes: 339
struct subordinate_range is pretty closely tied to the existing
subid code and /etc/subuid format, so it includes an owner. Dropping
that or even renaming it is more painful than I'd first thought.
So introduce a 'struct subid_range' which is only the start and
count, leaving 'struct subordinate_range' as the owner, start and
count.
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Closes#325
Add a new subid_init() function which can be used to specify the
stream on which error messages should be printed. (If you want to
get fancy you can redirect that to memory :) If subid_init() is
not called, use stderr. If NULL is passed, then /dev/null will
be used.
This patch also fixes up the 'Prog', which previously had to be
defined by any program linking against libsubid. Now, by default
in libsubid it will show (subid). Once subid_init() is called,
it will use the first variable passed to subid_init().
Signed-off-by: Serge Hallyn <serge@hallyn.com>
Include the new HMAC_CRYPTO_ALGO key that is needed by pam_timestamp to
select the algorithm that is going to be used to calculate the message
authentication code.
pam_timestamp is currently using an embedded algorithm to calculate the
HMAC message, but the idea is to improve this behaviour by relying on
openssl's implementation. On top of that, the ability to change the
algorithm with a simple configuration change allows to simplify the
process of removing unsecure algorithms.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1947294
Once opened, keep the selabel database open for further lookups.
Register an exit handler to close the database.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Search the SELinux selabel database for the file type to be created.
Not specifying the file mode can cause an incorrect file context to be
returned.
Also prepare contexts in commonio_close() for the generic database
filename, not with the backup suffix appended, to ensure the desired
file context after the final rename.
Closes: #322
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
matchpathcon(3) is deprecated in favor of selabel_lookup(3).
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Return 0 on setfscreatecon(3) failure, like set_selinux_file_context().
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
These retrieved contexts are just passed to libselinux functions and not
printed or otherwise made available to the outside, so a context
translation to human readable MCS/MLS labels is not needed.
(see man:setrans.conf(5))
The typedef security_context_t is deprecated, see
9eb9c93275
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
The typedef security_context_t is deprecated, see
9eb9c93275
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
Closes#154
When starting any operation to do with subuid delegation, check
nsswitch for a module to use. If none is specified, then use
the traditional /etc/subuid and /etc/subgid files.
Currently only one module is supported, and there is no fallback
to the files on errors. Several possibilities could be considered:
1. in case of connection error, fall back to files
2. in case of unknown user, also fall back to files
etc...
When non-files nss module is used, functions to edit the range
are not supported. It may make sense to support it, but it also
may make sense to require another tool to be used.
libsubordinateio also uses the nss_ helpers. This is how for instance
lxc could easily be converted to supporting nsswitch.
Add a set of test cases, including a dummy libsubid_zzz module. This
hardcodes values such that:
'ubuntu' gets 200000 - 300000
'user1' gets 100000 - 165536
'error' emulates an nss module error
'unknown' emulates a user unknown to the nss module
'conn' emulates a connection error ot the nss module
Changes to libsubid:
Change the list_owner_ranges api: return a count instead of making the array
null terminated.
This is a breaking change, so bump the libsubid abi major number.
Rename free_subuid_range and free_subgid_range to ungrant_subuid_range,
because otherwise it's confusing with free_subid_ranges which frees
memory.
Run libsubid tests in jenkins
Switch argument order in find_subid_owners
Move the db locking into subordinateio.c
Signed-off-by: Serge Hallyn <serge@hallyn.com>
* login & su: Treat an empty passwd field as invalid
Otherwise it's treated like the “require no password” clause while it probably
should be treated like a normal su that can't validate anyway.
A similar change should be done for USE_PAM.
* su & login: Introduce PREVENT_NO_AUTH
The login.defs is shared between more upstream projects (util-linux,
etc.). We need to improve compatibility between the projects do not
report valid, but foreign items.
Addresses: https://github.com/shadow-maint/shadow/issues/276
Signed-off-by: Karel Zak <kzak@redhat.com>
Closes#154
Currently this has three functions: one which returns the
list of subuid ranges for a user, one returning the subgids,
and one which frees the ranges lists.
I might be mistaken about what -disable-man means; some of
the code suggests it means just don't re-generate them, but
not totally ignore them. But that doesn't seem to really work,
so let's just ignore man/ when -disable-man.
Remove --disable-shared. I'm not sure why it was there, but it stems
from long, long ago, and I suspect it comes from some ancient
toolchain bug.
Create a tests/run_some, a shorter version of run_all. I'll
slowly add tests to this as I verify they work, then I can
work on fixing the once which don't.
Also, don't touch man/ if not -enable-man.
Changelog:
Apr 22: change the subid list api as recomended by Dan Walsh.
Apr 23: implement get_subid_owner
Apr 24: implement range add/release
Apr 25: finish tests and rebase
May 10: make @owner const
Signed-off-by: Serge Hallyn <serge@hallyn.com>
This option can be used to set a separate mode for useradd(8) and
newusers(8) to create the home directories with.
If this option is not set, the current behavior of using UMASK
or the default umask is preserved.
There are many distributions that set UMASK to 077 by default just
to create home directories not readable by others and use things like
/etc/profile, bashrc or sudo configuration files to set a less
restrictive
umask. This has always resulted in bug reports because it is hard
to follow as users tend to change files like bashrc and are not about
setting the umask to counteract the umask set in /etc/login.defs.
A recent change in sudo has also resulted in many bug reports about
this. sudo now tries to respect the umask set by pam modules and on
systems where pam does not set a umask, the login.defs UMASK value is
used.
This option can be used to set a separate mode for useradd(8) and
newusers(8) to create the home directories with.
If this option is not set, the current behavior of using UMASK
or the default umask is preserved.
There are many distributions that set UMASK to 077 by default just
to create home directories not readable by others and use things like
/etc/profile, bashrc or sudo configuration files to set a less
restrictive
umask. This has always resulted in bug reports because it is hard
to follow as users tend to change files like bashrc and are not about
setting the umask to counteract the umask set in /etc/login.defs.
A recent change in sudo has also resulted in many bug reports about
this. sudo now tries to respect the umask set by pam modules and on
systems where pam does not set a umask, the login.defs UMASK value is
used.
Using hard-coded access vector ids is deprecated and can lead to issues with custom SELinux policies.
Switch to `selinux_check_access()`.
Also use the libselinux log callback and log if available to audit.
This makes it easier for users to catch SELinux denials.
Drop legacy shortcut logic for passwd, which avoided a SELinux check if uid 0 changes a password of a user which username equals the current SELinux user identifier.
Nowadays usernames rarely match SELinux user identifiers and the benefit of skipping a SELinux check is negligible.
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
With this, it is possible for Linux distributors to store their
supplied default configuration files somewhere below /usr, while
/etc only contains the changes made by the user. The new option
--enable-vendordir defines where the shadow suite should additional
look for login.defs if this file is not in /etc.
libeconf is a key/value configuration file reading library, which
handles the split of configuration files in different locations
and merges them transparently for the application.
new switch added to useradd command, --btrfs-subvolume-home. When
specified *and* the filesystem is detected as btrfs, it will create a
subvolume for user's home instead of a plain directory. This is done via
`btrfs subvolume` command. Specifying the new switch while trying to
create home on non-btrfs will result in an error.
userdel -r will handle and remove this subvolume transparently via
`btrfs subvolume` command. Previosuly this failed as you can't rmdir a
subvolume.
usermod, when moving user's home across devices, will detect if the home
is a subvolume and issue an error messages instead of copying it. Moving
user's home (as subvolume) on same btrfs works transparently.
As the lockfiles have PID in the name, there can be no conflict
in the name with other process, so there is no point in using
O_EXCL and it only can fail if there is a stale lockfile from
previous execution that crashed for some reason.
The implementation of prefix option dropped the use of lckpwdf().
However that is incorrect as other tools manipulating the shadow passwords
such as PAM use lckpwdf() and do not know anything about the
shadow's own locking mechanism.
This reverts the implementation to use lckpwdf() if prefix option
is not used.
As the large uids are usually provided by remote user identity and
authentication service, which also provide user login tracking,
there is no need to create a huge sparse file for them on every local
machine.
fixup! login.defs: Add LASTLOG_UID_MAX variable to limit lastlog to small uids.
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.
This allows shadow-utils to build on systems like Adélie, which have no
<utmp.h> header or `struct utmp`. We use a <utmpx.h>-based daemon,
utmps[1], which uses `struct utmpx` only.
Tested both `login` and `logoutd` with utmps and both work correctly.
[1]: http://skarnet.org/software/utmps/
