Before 3b7cc05387 ("lib: replace `USER_NAME_MAX_LENGTH` macro"), this
code did use a length. It used a utmp(5) fixed-width buffer, so the
length matches the buffer size (there was no terminating NUL byte).
However, sysconf(_SC_LOGIN_NAME_MAX) returns a buffer size that accounts
for the terminating null byte; see sysconf(3). Thus, the commit that
introduced the call to sysconf(3), should have taken that detail into
account.
403a2e3771 ("lib/chkname.c: Take NUL byte into account"), by Tobias,
caught that bug in <lib/chkname.c>, but missed that the same commit that
introduced that bug, introduced the same bug in two other places.
This fixes all remaining calls to sysconf(_SC_LOGIN_NAME_MAX).
I still observe some suspicious code after this fix:
if (do_rlogin(hostname, username, max_size - 1, term, sizeof(term)))
...
login_prompt(username, max_size - 1);
We're passing size-1 to functions that want a size. But since the fix
to those will be different, let's do that in the following commits.
Link: <https://github.com/shadow-maint/shadow/pull/935>
Link: <https://github.com/shadow-maint/shadow/issues/920#issuecomment-1926002209>
Link: <https://github.com/shadow-maint/shadow/pull/757>
Link: <https://github.com/shadow-maint/shadow/issues/674>
See-also: 403a2e3771 ("lib/chkname.c: Take NUL byte into account")
Fixes: 3b7cc05387 ("lib: replace `USER_NAME_MAX_LENGTH` macro")
Reviewed-by: Iker Pedrosa <ipedrosa@redhat.com>
Cc: Tobias Stoeckmann <tobias@stoeckmann.org>
Cc: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Cherry-picked-from: 6551709e96 ("src/login.c: Fix off-by-one buggs")
Link: <https://github.com/shadow-maint/shadow/pull/936>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Remove `utmp` structure as an argument and include its logic inside the
function. This will help remove any reference to utmp from login.
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
The functionality from this function is related to utmp. Restrict access
to `setutmp()` to the same file.
Signed-off-by: Iker Pedrosa <ipedrosa@redhat.com>
If we consider simple objects as arrays of size 1, we can considerably
simplify these APIs, merging the *ARRAY and the non-array variants.
That will produce more readable code, since lines will be shorter (by
not having ARRAY in the macro names, as all macros will consistently
handle arrays), and the allocated size will be also more explicit.
The syntax will now be of the form:
p = MALLOC(42, foo_t); // allocate 42 elements of type foo_t.
p = MALLOC(1, bar_t); // allocate 1 element of type foo_t.
The _array() allocation functions should _never_ be called directly, and
instead these macros should be used.
The non-array functions (e.g., malloc(3)) still have their place, but
are limited to allocating structures with flexible array members. For
any other uses, the macros should be used.
Thus, we don't use any array or ARRAY variants in any code any more, and
they are only used as implementation details of these macros.
Link: <https://software.codidact.com/posts/285898/288023#answer-288023>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
The only user of login_prompt is the login tool. This implies that the
first argument is always the same.
It is much easier to verify printf's format string and its argument if
both are next to each other.
Signed-off-by: Samanta Navarro <ferivoz@riseup.net>
Use of these macros, apart from the benefits mentioned in the commit
that adds the macros, has some other good side effects:
- Consistency in getting the size of the object from sizeof(type),
instead of a mix of sizeof(type) sometimes and sizeof(*p) other
times.
- More readable code: no casts, and no sizeof(), so also shorter lines
that we don't need to cut.
- Consistency in using array allocation calls for allocations of arrays
of objects, even when the object size is 1.
Cc: Valentin V. Bartenev <vbartenev@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
- Every non-const pointer converts automatically to void *.
- Every pointer converts automatically to void *.
- void * converts to any other pointer.
- const void * converts to any other const pointer.
- Integer variables convert to each other.
I changed the declaration of a few variables in order to allow removing
a cast.
However, I didn't attempt to edit casts inside comparisons, since they
are very delicate. I also kept casts in variadic functions, since they
are necessary, and in allocation functions, because I have other plans
for them.
I also changed a few casts to int that are better as ptrdiff_t.
This change has triggered some warnings about const correctness issues,
which have also been fixed in this patch (see for example src/login.c).
Signed-off-by: Alejandro Colomar <alx@kernel.org>
In variadic functions we still do the cast. In POSIX, it's not
necessary, since NULL is required to be of type 'void *', and 'void *'
is guaranteed to have the same alignment and representation as 'char *'.
However, since ISO C still doesn't mandate that, and moreover they're
doing dubious stuff by adding nullptr, let's be on the cautious side.
Also, C++ requires that NULL is _not_ 'void *', but either plain 0 or
some magic stuff.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Login timed out message prints only first few bytes when write is immediately followed by exit.
Calling exit from new handler provides enough time to display full message.
Previous commits, to keep readability of the diffs, left the code that
was previously wrapped by preprocessor coditionals untouched. Apply
some minor cosmetic changes to merge it in the surrounding code.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
On Linux, utmpx and utmp are identical. However, documentation (manual
pages) covers utmp, and just says about utmpx that it's identical to
utmp. It seems that it's preferred to use utmp, at least by reading the
manual pages.
Moreover, we were defaulting to utmp (utmpx had to be explicitly enabled
at configuration time). So, it seems safer to just make it permanent,
which should not affect default builds.
Signed-off-by: Alejandro Colomar <alx@kernel.org>
free(3) accepts NULL, since the oldest ISO C. I guess the
paranoid code was taking care of prehistoric implementations of
free(3). I've never known of an implementation that doesn't
conform to this, so let's simplify this.
Remove xfree(3), which was effectively an equivalent of free(3).
Signed-off-by: Alejandro Colomar <alx@kernel.org>
C89 and POSIX.1-2001 define signal(2) as returning a pointer to a
function returning 'void'. K&R C signal(2) signature is obsolete.
Use 'void' directly.
Also, instead of writing the function pointer type explicitly, use
POSIX's 'sighandler_t'.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
strftime(3) has been in standard C since C89. It is also in
POSIX.1-2001, and in SVr4 (see strftime(3) and strftime(3p)).
We can assume that this function is always available.
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
This conforms to PAM documentation and it is needed to support
ambient capabilities with PAM + libcap-2.58+.
Signed-off-by: Björn Fischer <bf@CeBiTec.Uni-Bielefeld.DE>
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>
* 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
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.
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/
Some of the supplied tools use functions which are not signal-safe.
Most of the times it's exit() vs. _exit().
In other times it's how the standard output or standard error is
handled. FILE-related functions shall be avoided, therefore I replaced
them with write().
Also there is no need to call closelog(). At worst, it allows to
trigger a deadlock by issuing different signal types at bad timings.
But as these fixes are about race conditions, expect bad timings in
general for these bugs to be triggered. :)
enabled. This is not done by pam_lastlog. This was broken on
2011-07-23.
* NEWS, libmisc/utmp.c: Do not log in wtmp when PAM is enabled.
This is done by pam_lastlog.
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.
* 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.
Alejandro Colomar
Christian Göttsche
Iker Pedrosa
Samanta Navarro
SoumyaWind
Alex Colomar
Serge Hallyn
Björn Fischer
a1346054
Haelwenn Monnier
Serge Hallyn
Tomas Mraz
A. Wilcox
Josh Soref
Tobias Stoeckmann
nekral-guest