sys-apps/shadow: backport password leak fix, backport usermod gid --prefix fix

Bug: https://bugs.gentoo.org/908613
Closes: https://bugs.gentoo.org/894754
Signed-off-by: Sam James <sam@gentoo.org>

3 files changed, 436 insertions, 0 deletions

diff --git a/sys-apps/shadow/files/shadow-4.13-password-leak.patch b/sys-apps/shadow/files/shadow-4.13-password-leak.patch
new file mode 100644
index 000000000000..25b5ec39c5f8
--- /dev/null
+++ b/sys-apps/shadow/files/shadow-4.13-password-leak.patch
@@ -0,0 +1,135 @@
+https://github.com/shadow-maint/shadow/commit/65c88a43a23c2391dcc90c0abda3e839e9c57904
+
+From 65c88a43a23c2391dcc90c0abda3e839e9c57904 Mon Sep 17 00:00:00 2001
+From: Alejandro Colomar <alx@kernel.org>
+Date: Sat, 10 Jun 2023 16:20:05 +0200
+Subject: [PATCH] gpasswd(1): Fix password leak
+
+How to trigger this password leak?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+When gpasswd(1) asks for the new password, it asks twice (as is usual
+for confirming the new password).  Each of those 2 password prompts
+uses agetpass() to get the password.  If the second agetpass() fails,
+the first password, which has been copied into the 'static' buffer
+'pass' via STRFCPY(), wasn't being zeroed.
+
+agetpass() is defined in <./libmisc/agetpass.c> (around line 91), and
+can fail for any of the following reasons:
+
+-  malloc(3) or readpassphrase(3) failure.
+
+   These are going to be difficult to trigger.  Maybe getting the system
+   to the limits of memory utilization at that exact point, so that the
+   next malloc(3) gets ENOMEM, and possibly even the OOM is triggered.
+   About readpassphrase(3), ENFILE and EINTR seem the only plausible
+   ones, and EINTR probably requires privilege or being the same user;
+   but I wouldn't discard ENFILE so easily, if a process starts opening
+   files.
+
+-  The password is longer than PASS_MAX.
+
+   The is plausible with physical access.  However, at that point, a
+   keylogger will be a much simpler attack.
+
+And, the attacker must be able to know when the second password is being
+introduced, which is not going to be easy.
+
+How to read the password after the leak?
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Provoking the leak yourself at the right point by entering a very long
+password is easy, and inspecting the process stack at that point should
+be doable.  Try to find some consistent patterns.
+
+Then, search for those patterns in free memory, right after the victim
+leaks their password.
+
+Once you get the leak, a program should read all the free memory
+searching for patterns that gpasswd(1) leaves nearby the leaked
+password.
+
+On 6/10/23 03:14, Seth Arnold wrote:
+> An attacker process wouldn't be able to use malloc(3) for this task.
+> There's a handful of tools available for userspace to allocate memory:
+>
+> -  brk / sbrk
+> -  mmap MAP_ANONYMOUS
+> -  mmap /dev/zero
+> -  mmap some other file
+> -  shm_open
+> -  shmget
+>
+> Most of these return only pages of zeros to a process.  Using mmap of an
+> existing file, you can get some of the contents of the file demand-loaded
+> into the memory space on the first use.
+>
+> The MAP_UNINITIALIZED flag only works if the kernel was compiled with
+> CONFIG_MMAP_ALLOW_UNINITIALIZED.  This is rare.
+>
+> malloc(3) doesn't zero memory, to our collective frustration, but all the
+> garbage in the allocations is from previous allocations in the current
+> process.  It isn't leftover from other processes.
+>
+> The avenues available for reading the memory:
+> -  /dev/mem and /dev/kmem (requires root, not available with Secure Boot)
+> -  /proc/pid/mem (requires ptrace privileges, mediated by YAMA)
+> -  ptrace (requires ptrace privileges, mediated by YAMA)
+> -  causing memory to be swapped to disk, and then inspecting the swap
+>
+> These all require a certain amount of privileges.
+
+How to fix it?
+~~~~~~~~~~~~~
+
+memzero(), which internally calls explicit_bzero(3), or whatever
+alternative the system provides with a slightly different name, will
+make sure that the buffer is zeroed in memory, and optimizations are not
+allowed to impede this zeroing.
+
+This is not really 100% effective, since compilers may place copies of
+the string somewhere hidden in the stack.  Those copies won't get zeroed
+by explicit_bzero(3).  However, that's arguably a compiler bug, since
+compilers should make everything possible to avoid optimizing strings
+that are later passed to explicit_bzero(3).  But we all know that
+sometimes it's impossible to have perfect knowledge in the compiler, so
+this is plausible.  Nevertheless, there's nothing we can do against such
+issues, except minimizing the time such passwords are stored in plain
+text.
+
+Security concerns
+~~~~~~~~~~~~~~~~
+
+We believe this isn't easy to exploit.  Nevertheless, and since the fix
+is trivial, this fix should probably be applied soon, and backported to
+all supported distributions, to prevent someone else having more
+imagination than us to find a way.
+
+Affected versions
+~~~~~~~~~~~~~~~~
+
+All.  Bug introduced in shadow 19990709.  That's the second commit in
+the git history.
+
+Fixes: 45c6603cc86c ("[svn-upgrade] Integrating new upstream version, shadow (19990709)")
+Reported-by: Alejandro Colomar <alx@kernel.org>
+Cc: Serge Hallyn <serge@hallyn.com>
+Cc: Iker Pedrosa <ipedrosa@redhat.com>
+Cc: Seth Arnold <seth.arnold@canonical.com>
+Cc: Christian Brauner <christian@brauner.io>
+Cc: Balint Reczey <rbalint@debian.org>
+Cc: Sam James <sam@gentoo.org>
+Cc: David Runge <dvzrv@archlinux.org>
+Cc: Andreas Jaeger <aj@suse.de>
+Cc: <~hallyn/shadow@lists.sr.ht>
+Signed-off-by: Alejandro Colomar <alx@kernel.org>
+--- a/src/gpasswd.c
++++ b/src/gpasswd.c
+@@ -898,6 +898,7 @@ static void change_passwd (struct group *gr)
+ 		erase_pass (cp);
+ 		cp = agetpass (_("Re-enter new password: "));
+ 		if (NULL == cp) {
++			memzero (pass, sizeof pass);
+ 			exit (1);
+ 		}
+ 
diff --git a/sys-apps/shadow/files/shadow-4.13-usermod-prefix-gid.patch b/sys-apps/shadow/files/shadow-4.13-usermod-prefix-gid.patch
new file mode 100644
index 000000000000..50cbe699d15e
--- /dev/null
+++ b/sys-apps/shadow/files/shadow-4.13-usermod-prefix-gid.patch
@@ -0,0 +1,33 @@
+https://bugs.gentoo.org/903083
+https://github.com/shadow-maint/shadow/pull/691
+https://github.com/shadow-maint/shadow/commit/bd2d0079c90241f24671a7946a3ad175dc1a3aeb
+
+From fcb04de38a0ddc263288a1c450b35bfb1503d523 Mon Sep 17 00:00:00 2001
+From: Mike Gilbert <floppym@gentoo.org>
+Date: Sat, 25 Mar 2023 21:16:55 -0400
+Subject: [PATCH] usermod: respect --prefix for --gid option
+
+The --gid option accepts a group name or id. When a name is provided, it
+is resolved to an id by looking up the name in the group database
+(/etc/group).
+
+The --prefix option overides the location of the passwd and group
+databases. I suspect the --gid option was overlooked when wiring up the
+--prefix option.
+
+useradd --gid already respects --prefix; this change makes usermod
+behave the same way.
+
+Fixes: b6b2c756c91806b1c3e150ea0ee4721c6cdaf9d0
+Signed-off-by: Mike Gilbert <floppym@gentoo.org>
+--- a/src/usermod.c
++++ b/src/usermod.c
+@@ -1072,7 +1072,7 @@ static void process_flags (int argc, char **argv)
+ 				fflg = true;
+ 				break;
+ 			case 'g':
+-				grp = getgr_nam_gid (optarg);
++				grp = prefix_getgr_nam_gid (optarg);
+ 				if (NULL == grp) {
+ 					fprintf (stderr,
+ 					         _("%s: group '%s' does not exist\n"),
diff --git a/sys-apps/shadow/shadow-4.13-r4.ebuild b/sys-apps/shadow/shadow-4.13-r4.ebuild
new file mode 100644
index 000000000000..aa20387a875e
--- /dev/null
+++ b/sys-apps/shadow/shadow-4.13-r4.ebuild
@@ -0,0 +1,268 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+# Upstream sometimes pushes releases as pre-releases before marking them
+# official. Don't keyword the pre-releases!
+# Check https://github.com/shadow-maint/shadow/releases.
+
+VERIFY_SIG_OPENPGP_KEY_PATH="${BROOT}"/usr/share/openpgp-keys/sergehallyn.asc
+inherit libtool pam verify-sig
+
+DESCRIPTION="Utilities to deal with user accounts"
+HOMEPAGE="https://github.com/shadow-maint/shadow"
+SRC_URI="https://github.com/shadow-maint/shadow/releases/download/${PV}/${P}.tar.xz"
+SRC_URI+=" verify-sig? ( https://github.com/shadow-maint/shadow/releases/download/${PV}/${P}.tar.xz.asc )"
+
+LICENSE="BSD GPL-2"
+# Subslot is for libsubid's SONAME.
+SLOT="0/4"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+IUSE="acl audit bcrypt cracklib nls pam selinux skey split-usr su xattr"
+# Taken from the man/Makefile.am file.
+LANGS=( cs da de es fi fr hu id it ja ko pl pt_BR ru sv tr zh_CN zh_TW )
+
+REQUIRED_USE="?? ( cracklib pam )"
+
+COMMON_DEPEND="
+	virtual/libcrypt:=
+	acl? ( sys-apps/acl:= )
+	audit? ( >=sys-process/audit-2.6:= )
+	cracklib? ( >=sys-libs/cracklib-2.7-r3:= )
+	nls? ( virtual/libintl )
+	pam? ( sys-libs/pam:= )
+	skey? ( sys-auth/skey:= )
+	selinux? (
+		>=sys-libs/libselinux-1.28:=
+		sys-libs/libsemanage:=
+	)
+	xattr? ( sys-apps/attr:= )
+"
+DEPEND="
+	${COMMON_DEPEND}
+	>=sys-kernel/linux-headers-4.14
+"
+RDEPEND="
+	${COMMON_DEPEND}
+	!<sys-apps/man-pages-5.11-r1
+	!=sys-apps/man-pages-5.12-r0
+	!=sys-apps/man-pages-5.12-r1
+	nls? (
+		!<app-i18n/man-pages-it-5.06-r1
+		!<app-i18n/man-pages-ja-20180315-r1
+		!<app-i18n/man-pages-ru-5.03.2390.2390.20191017-r1
+	)
+	pam? ( >=sys-auth/pambase-20150213 )
+	su? ( !sys-apps/util-linux[su(-)] )
+"
+BDEPEND="
+	app-arch/xz-utils
+	sys-devel/gettext
+	verify-sig? ( sec-keys/openpgp-keys-sergehallyn )
+"
+
+PATCHES=(
+	"${FILESDIR}"/${P}-configure-clang16.patch
+	"${FILESDIR}"/${P}-CVE-2023-29383.patch
+	"${FILESDIR}"/${P}-usermod-prefix-gid.patch
+	"${FILESDIR}"/${P}-password-leak.patch
+)
+
+src_prepare() {
+	default
+
+	elibtoolize
+}
+
+src_configure() {
+	local myeconfargs=(
+		--disable-account-tools-setuid
+		--disable-static
+		--with-btrfs
+		--without-group-name-max-length
+		--without-tcb
+		$(use_enable nls)
+		$(use_with acl)
+		$(use_with audit)
+		$(use_with bcrypt)
+		$(use_with cracklib libcrack)
+		$(use_with elibc_glibc nscd)
+		$(use_with pam libpam)
+		$(use_with selinux)
+		$(use_with skey)
+		$(use_with su)
+		$(use_with xattr attr)
+	)
+
+	econf "${myeconfargs[@]}"
+
+	if use nls ; then
+		local l langs="po" # These are the pot files.
+		for l in ${LANGS[*]} ; do
+			has ${l} ${LINGUAS-${l}} && langs+=" ${l}"
+		done
+		sed -i "/^SUBDIRS = /s:=.*:= ${langs}:" man/Makefile || die
+	fi
+}
+
+set_login_opt() {
+	local comment="" opt=${1} val=${2}
+	if [[ -z ${val} ]]; then
+		comment="#"
+		sed -i \
+			-e "/^${opt}\>/s:^:#:" \
+			"${ED}"/etc/login.defs || die
+	else
+		sed -i -r \
+			-e "/^#?${opt}\>/s:.*:${opt} ${val}:" \
+			"${ED}"/etc/login.defs
+	fi
+	local res=$(grep "^${comment}${opt}\>" "${ED}"/etc/login.defs)
+	einfo "${res:-Unable to find ${opt} in /etc/login.defs}"
+}
+
+src_install() {
+	emake DESTDIR="${D}" suidperms=4711 install
+
+	# 4.9 regression: https://github.com/shadow-maint/shadow/issues/389
+	emake DESTDIR="${D}" -C man install
+
+	find "${ED}" -name '*.la' -type f -delete || die
+
+	insinto /etc
+	if ! use pam ; then
+		insopts -m0600
+		doins etc/login.access etc/limits
+	fi
+
+	# needed for 'useradd -D'
+	insinto /etc/default
+	insopts -m0600
+	doins "${FILESDIR}"/default/useradd
+
+	if use split-usr ; then
+		# move passwd to / to help recover broke systems #64441
+		# We cannot simply remove this or else net-misc/scponly
+		# and other tools will break because of hardcoded passwd
+		# location
+		dodir /bin
+		mv "${ED}"/usr/bin/passwd "${ED}"/bin/ || die
+		dosym ../../bin/passwd /usr/bin/passwd
+	fi
+
+	cd "${S}" || die
+	insinto /etc
+	insopts -m0644
+	newins etc/login.defs login.defs
+
+	set_login_opt CREATE_HOME yes
+	if ! use pam ; then
+		set_login_opt MAIL_CHECK_ENAB no
+		set_login_opt SU_WHEEL_ONLY yes
+		set_login_opt CRACKLIB_DICTPATH /usr/lib/cracklib_dict
+		set_login_opt LOGIN_RETRIES 3
+		set_login_opt ENCRYPT_METHOD SHA512
+		set_login_opt CONSOLE
+	else
+		dopamd "${FILESDIR}"/pam.d-include/shadow
+
+		for x in chsh chfn ; do
+			newpamd "${FILESDIR}"/pam.d-include/passwd ${x}
+		done
+
+		for x in chpasswd newusers ; do
+			newpamd "${FILESDIR}"/pam.d-include/chpasswd ${x}
+		done
+
+		newpamd "${FILESDIR}"/pam.d-include/shadow-r1 groupmems
+
+		# Comment out login.defs options that pam hates
+		local opt sed_args=()
+		for opt in \
+			CHFN_AUTH \
+			CONSOLE \
+			CRACKLIB_DICTPATH \
+			ENV_HZ \
+			ENVIRON_FILE \
+			FAILLOG_ENAB \
+			FTMP_FILE \
+			LASTLOG_ENAB \
+			MAIL_CHECK_ENAB \
+			MOTD_FILE \
+			NOLOGINS_FILE \
+			OBSCURE_CHECKS_ENAB \
+			PASS_ALWAYS_WARN \
+			PASS_CHANGE_TRIES \
+			PASS_MIN_LEN \
+			PORTTIME_CHECKS_ENAB \
+			QUOTAS_ENAB \
+			SU_WHEEL_ONLY
+		do
+			set_login_opt ${opt}
+			sed_args+=( -e "/^#${opt}\>/b pamnote" )
+		done
+		sed -i "${sed_args[@]}" \
+			-e 'b exit' \
+			-e ': pamnote; i# NOTE: This setting should be configured via /etc/pam.d/ and not in this file.' \
+			-e ': exit' \
+			"${ED}"/etc/login.defs || die
+
+		# Remove manpages that pam will install for us
+		# and/or don't apply when using pam
+		find "${ED}"/usr/share/man -type f \
+			'(' -name 'limits.5*' -o -name 'suauth.5*' ')' \
+			-delete
+
+		# Remove pam.d files provided by pambase.
+		rm "${ED}"/etc/pam.d/{login,passwd} || die
+		if use su ; then
+			rm "${ED}"/etc/pam.d/su || die
+		fi
+	fi
+
+	# Remove manpages that are handled by other packages
+	find "${ED}"/usr/share/man -type f \
+		'(' -name id.1 -o -name getspnam.3 ')' \
+		-delete || die
+
+	if ! use su ; then
+		find "${ED}"/usr/share/man -type f -name su.1 -delete || die
+	fi
+
+	cd "${S}" || die
+	dodoc ChangeLog NEWS TODO
+	newdoc README README.download
+	cd doc || die
+	dodoc HOWTO README* WISHLIST *.txt
+}
+
+pkg_preinst() {
+	rm -f "${EROOT}"/etc/pam.d/system-auth.new \
+		"${EROOT}/etc/login.defs.new"
+}
+
+pkg_postinst() {
+	# Missing entries from /etc/passwd can cause odd system blips.
+	# See bug #829872.
+	if ! pwck -r -q -R "${EROOT:-/}" &>/dev/null ; then
+		ewarn "Running 'pwck' returned errors. Please run it manually to fix any errors."
+	fi
+
+	# Enable shadow groups.
+	if [[ ! -f "${EROOT}"/etc/gshadow ]] ; then
+		if grpck -r -R "${EROOT:-/}" 2>/dev/null ; then
+			grpconv -R "${EROOT:-/}"
+		else
+			ewarn "Running 'grpck' returned errors. Please run it by hand, and then"
+			ewarn "run 'grpconv' afterwards!"
+		fi
+	fi
+
+	[[ ! -f "${EROOT}"/etc/subgid ]] &&
+		touch "${EROOT}"/etc/subgid
+	[[ ! -f "${EROOT}"/etc/subuid ]] &&
+		touch "${EROOT}"/etc/subuid
+
+	einfo "The 'adduser' symlink to 'useradd' has been dropped."
+}