All of the macros we're using are required by POSIX.1-2001.
Cc: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
The function is obsolete. It is recommended to use getrlimit(2) instead
(see the manual page for ulimit(3) or the POSIX manual for it). Since
getrlimit(2) is required by POSIX.1-2001, we can rely on it.
Cc: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
ISO C99 requires <locale.h>.
Other files in the project already include <locale.h> unconditionally,
so it's reasonable to assume that it is always available.
Link: <https://github.com/shadow-maint/shadow/pull/600>
Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
ISO C99 requires <errno.h>.
Many files in the project already include <errno.h> unconditionally,
so it's reasonable to assume that it is always available.
Link: <https://github.com/shadow-maint/shadow/pull/600>
Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
ISO C99 requires <stdbool.h>.
Many files in the project already include <stdbool.h> unconditionally,
so it's reasonable to assume that it is always available.
Link: <https://github.com/shadow-maint/shadow/pull/600>
Cc: Christian Göttsche <cgzones@googlemail.com>
Cc: Iker Pedrosa <ipedrosa@redhat.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Clang doesn't implement this attribute and reports an error. Work
around it by hiding it in a macro that will be empty in clang.
Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
getpass(3) is broken in all implementations; in some, more than
others, but somewhat broken in all of them. Check the immediate
previous commit, which added the functions, for more details.
Check also the Linux man-pages commit that marked it as
deprecated, for more details:
7ca189099d73bde954eed2d7fc21732bcc8ddc6b.
Link: <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit?id=7ca189099d73bde954eed2d7fc21732bcc8ddc6b>
Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
There are several issues with getpass(3).
Many implementations of it share the same issues that the infamous
gets(3). In glibc it's not so terrible, since it's a wrapper
around getline(3). But it still has an important bug:
If the password is long enough, getline(3) will realloc(3) memory,
and prefixes of the password will be laying around in some
deallocated memory.
See the getpass(3) manual page for more details, and especially
the commit that marked it as deprecated, which links to a long
discussion in the linux-man@ mailing list.
So, readpassphrase(3bsd) is preferrable, which is provided by
libbsd on GNU systems. However, using readpassphrase(3) directly
is a bit verbose, so we can write our own wrapper with a simpler
interface similar to that of getpass(3).
One of the benefits of writing our own interface around
readpassphrase(3) is that we can hide there any checks that should
be done always and which would be error-prone to repeat every
time. For example, check that there was no truncation in the
password.
Also, use malloc(3) to get the buffer, instead of using a global
buffer. We're not using a multithreaded program (and it wouldn't
make sense to do so), but it's nice to know that the visibility of
our passwords is as limited as possible.
erase_pass() is a clean-up function that handles all clean-up
correctly, including zeroing the entire buffer, and then
free(3)ing the memory. By using [[gnu::malloc(erase_pass)]], we
make sure that we don't leak the buffers in any case, since the
compiler will be able to enforce clean up.
Link: <https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/commit?id=7ca189099d73bde954eed2d7fc21732bcc8ddc6b>
Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
