--- /dev/null
+From 08fd4b69e84364677a10e519ccb25b71710ee686 Mon Sep 17 00:00:00 2001
+From: Tobias Stoeckmann <tobias@stoeckmann.org>
+Date: Thu, 23 Feb 2017 09:47:29 -0600
+Subject: [PATCH] su: properly clear child PID
+
+If su is compiled with PAM support, it is possible for any local user
+to send SIGKILL to other processes with root privileges. There are
+only two conditions. First, the user must be able to perform su with
+a successful login. This does NOT have to be the root user, even using
+su with the same id is enough, e.g. "su $(whoami)". Second, SIGKILL
+can only be sent to processes which were executed after the su process.
+It is not possible to send SIGKILL to processes which were already
+running. I consider this as a security vulnerability, because I was
+able to write a proof of concept which unlocked a screen saver of
+another user this way.
+---
+ src/su.c | 19 +++++++++++++++++--
+ 1 file changed, 17 insertions(+), 2 deletions(-)
+
+diff --git a/src/su.c b/src/su.c
+index f20d230..d86aa86 100644
+--- a/src/su.c
++++ b/src/su.c
+@@ -379,11 +379,13 @@ static void prepare_pam_close_session (void)
+ /* wake child when resumed */
+ kill (pid, SIGCONT);
+ stop = false;
++ } else {
++ pid_child = 0;
+ }
+ } while (!stop);
+ }
+
+- if (0 != caught) {
++ if (0 != caught && 0 != pid_child) {
+ (void) fputs ("\n", stderr);
+ (void) fputs (_("Session terminated, terminating shell..."),
+ stderr);
+@@ -393,9 +395,22 @@ static void prepare_pam_close_session (void)
+ snprintf (wait_msg, sizeof wait_msg, _(" ...waiting for child to terminate.\n"));
+
+ (void) signal (SIGALRM, kill_child);
++ (void) signal (SIGCHLD, catch_signals);
+ (void) alarm (2);
+
+- (void) wait (&status);
++ sigemptyset (&ourset);
++ if ((sigaddset (&ourset, SIGALRM) != 0)
++ || (sigprocmask (SIG_BLOCK, &ourset, NULL) != 0)) {
++ fprintf (stderr, _("%s: signal masking malfunction\n"), Prog);
++ kill_child (0);
++ } else {
++ while (0 == waitpid (pid_child, &status, WNOHANG)) {
++ sigsuspend (&ourset);
++ }
++ pid_child = 0;
++ (void) sigprocmask (SIG_UNBLOCK, &ourset, NULL);
++ }
++
+ (void) fputs (_(" ...terminated.\n"), stderr);
+ }
+
--- /dev/null
+# Copyright 1999-2017 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Id$
+
+EAPI="5"
+
+inherit eutils libtool pam multilib
+
+DESCRIPTION="Utilities to deal with user accounts"
+HOMEPAGE="https://github.com/shadow-maint/shadow http://pkg-shadow.alioth.debian.org/"
+SRC_URI="https://github.com/shadow-maint/shadow/releases/download/${PV}/${P}.tar.gz"
+
+LICENSE="BSD GPL-2"
+SLOT="0"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~m68k ~mips ~ppc ~ppc64 ~s390 ~sh ~sparc ~x86"
+IUSE="acl audit cracklib nls pam selinux skey 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 )
+IUSE+=" $(printf 'linguas_%s ' ${LANGS[*]})"
+
+RDEPEND="acl? ( sys-apps/acl:0= )
+ audit? ( >=sys-process/audit-2.6:0= )
+ cracklib? ( >=sys-libs/cracklib-2.7-r3:0= )
+ pam? ( virtual/pam:0= )
+ skey? ( sys-auth/skey:0= )
+ selinux? (
+ >=sys-libs/libselinux-1.28:0=
+ sys-libs/libsemanage:0=
+ )
+ nls? ( virtual/libintl )
+ xattr? ( sys-apps/attr:0= )"
+DEPEND="${RDEPEND}
+ app-arch/xz-utils
+ nls? ( sys-devel/gettext )"
+RDEPEND="${RDEPEND}
+ pam? ( >=sys-auth/pambase-20150213 )"
+
+PATCHES=(
+ "${FILESDIR}"/${PN}-4.1.3-dots-in-usernames.patch
+ "${FILESDIR}"/${P}-su-snprintf.patch
+ "${FILESDIR}"/${P}-prototypes.patch
+ "${FILESDIR}"/${P}-load_defaults.patch
+ "${FILESDIR}"/${P}-CVE-2017-2616.patch #610804
+)
+
+src_prepare() {
+ epatch "${PATCHES[@]}"
+ epatch_user
+ #eautoreconf
+ elibtoolize
+}
+
+src_configure() {
+ econf \
+ --without-group-name-max-length \
+ --without-tcb \
+ --enable-shared=no \
+ --enable-static=yes \
+ $(use_with acl) \
+ $(use_with audit) \
+ $(use_with cracklib libcrack) \
+ $(use_with pam libpam) \
+ $(use_with skey) \
+ $(use_with selinux) \
+ $(use_enable nls) \
+ $(use_with elibc_glibc nscd) \
+ $(use_with xattr attr)
+ has_version 'sys-libs/uclibc[-rpc]' && sed -i '/RLOGIN/d' config.h #425052
+
+ if use nls ; then
+ local l langs="po" # These are the pot files.
+ for l in ${LANGS[*]} ; do
+ use linguas_${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
+
+ # Remove libshadow and libmisc; see bug 37725 and the following
+ # comment from shadow's README.linux:
+ # Currently, libshadow.a is for internal use only, so if you see
+ # -lshadow in a Makefile of some other package, it is safe to
+ # remove it.
+ rm -f "${ED}"/{,usr/}$(get_libdir)/lib{misc,shadow}.{a,la}
+
+ 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 "${FILESDIR}"/default/useradd
+
+ # move passwd to / to help recover broke systems #64441
+ mv "${ED}"/usr/bin/passwd "${ED}"/bin/ || die
+ dosym /bin/passwd /usr/bin/passwd
+
+ cd "${S}"
+ 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/$(get_libdir)/cracklib_dict
+ set_login_opt LOGIN_RETRIES 3
+ set_login_opt ENCRYPT_METHOD SHA512
+ set_login_opt CONSOLE
+ else
+ dopamd "${FILESDIR}"/pam.d-include/shadow
+
+ for x in chpasswd chgpasswd newusers; do
+ newpamd "${FILESDIR}"/pam.d-include/passwd ${x}
+ done
+
+ for x in chage chsh chfn \
+ user{add,del,mod} group{add,del,mod} ; do
+ newpamd "${FILESDIR}"/pam.d-include/shadow ${x}
+ done
+
+ # 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 "${ED}"/usr/share/man \
+ '(' -name 'limits.5*' -o -name 'suauth.5*' ')' \
+ -delete
+
+ # Remove pam.d files provided by pambase.
+ rm "${ED}"/etc/pam.d/{login,passwd,su} || die
+ fi
+
+ # Remove manpages that are handled by other packages
+ find "${ED}"/usr/share/man \
+ '(' -name id.1 -o -name passwd.5 -o -name getspnam.3 ')' \
+ -delete
+
+ cd "${S}"
+ dodoc ChangeLog NEWS TODO
+ newdoc README README.download
+ cd doc
+ dodoc HOWTO README* WISHLIST *.txt
+}
+
+pkg_preinst() {
+ rm -f "${EROOT}"/etc/pam.d/system-auth.new \
+ "${EROOT}/etc/login.defs.new"
+}
+
+pkg_postinst() {
+ # 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
+
+ einfo "The 'adduser' symlink to 'useradd' has been dropped."
+}
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