[manjaro-security] [systemd] CVE-2017-9445: Out-of-bounds write in systemd-resolved with crafted, TCP payload
Philip Müller
philm at manjaro.org
Thu Jun 29 08:29:13 CEST 2017
Hi Dave,
currently CVE-2017-9445[1] gets hyped.
Certain sizes passed to dns_packet_new can cause it to allocate a buffer
that's too small. A page-aligned number - sizeof(DnsPacket) +
sizeof(iphdr) + sizeof(udphdr) will do this - so, on x86 this will be a
page-aligned number - 80. Eg, calling dns_packet_new with a size of 4016
on x86 will result in an allocation of 4096 bytes, but 108 bytes of this
are for the DnsPacket struct.
A malicious DNS server can exploit this by responding with a specially
crafted TCP payload to trick systemd-resolved in to allocating a buffer
that's too small, and subsequently write arbitrary data beyond the end
of it.
Seems to be introduced by resolved: packet - ensure there is space for
IP+UDP headers[2].
You may find attached an updated PKGBUILD and the additional patch since
751ca3f doesn't apply clean.
I published the fixes to systemd 232-8.1 on my end.
kind regards, Philip
[1] http://www.openwall.com/lists/oss-security/2017/06/27/8
[2]
https://github.com/systemd/systemd/commit/a0166609f782da91710dea9183d1bf138538db37
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# Maintainer: Dave Reisner <dreisner at archlinux.org>
# Maintainer: Tom Gundersen <teg at jklm.no>
pkgbase=systemd
pkgname=('systemd' 'libsystemd' 'systemd-sysvcompat')
pkgver=232
pkgrel=8.1
arch=('i686' 'x86_64')
url="https://www.github.com/systemd/systemd"
makedepends=('acl' 'cryptsetup' 'docbook-xsl' 'gperf' 'lz4' 'xz' 'pam' 'libelf'
'intltool' 'iptables' 'kmod' 'libcap' 'libidn' 'libgcrypt'
'libmicrohttpd' 'libxslt' 'util-linux' 'linux-api-headers'
'python-lxml' 'quota-tools' 'shadow' 'gnu-efi-libs' 'git')
options=('strip')
source=("git://github.com/systemd/systemd.git#tag=v$pkgver"
'initcpio-hook-udev'
'initcpio-install-systemd'
'initcpio-install-udev'
'arch.conf'
'loader.conf'
'splash-arch.bmp'
'systemd-user.pam'
'systemd-hwdb.hook'
'systemd-sysusers.hook'
'systemd-tmpfiles.hook'
'systemd-update.hook'
'0001-disable-RestrictAddressFamilies-on-i686.patch'
'0001-Revert-nspawn-try-to-bind-mount-resolved-s-resolv.co.patch'
'0001-nspawn-don-t-hide-bind-tmp-mounts.patch'
'0001-test-resolved-packet-add-a-simple-test-for-our-alloc.patch')
sha512sums=('SKIP'
'f0d933e8c6064ed830dec54049b0a01e27be87203208f6ae982f10fb4eddc7258cb2919d594cbfb9a33e74c3510cfd682f3416ba8e804387ab87d1a217eb4b73'
'52af734947a768758d5eb3f18e31a1cfec6699eca6fa10e40b90c7f11991509186c0a696e3490af3eaba80064ea4cb93e041579abf05addf072d294300aa4b28'
'fec639de0d99967ed3e67289eff5ff78fff0c5829d350e73bed536a8391f1daa1d118d72dbdc1f480ffd33fc22b72f4817d0973bd09ec7f182fd26ad87b24355'
'61032d29241b74a0f28446f8cf1be0e8ec46d0847a61dadb2a4f096e8686d5f57fe5c72bcf386003f6520bc4b5856c32d63bf3efe7eb0bc0deefc9f68159e648'
'c416e2121df83067376bcaacb58c05b01990f4614ad9de657d74b6da3efa441af251d13bf21e3f0f71ddcb4c9ea658b81da3d915667dc5c309c87ec32a1cb5a5'
'5a1d78b5170da5abe3d18fdf9f2c3a4d78f15ba7d1ee9ec2708c4c9c2e28973469bc19386f70b3cf32ffafbe4fcc4303e5ebbd6d5187a1df3314ae0965b25e75'
'b90c99d768dc2a4f020ba854edf45ccf1b86a09d2f66e475de21fe589ff7e32c33ef4aa0876d7f1864491488fd7edb2682fc0d68e83a6d4890a0778dc2d6fe19'
'2c1f765e7cefc50f07ad994634ea25d9396e6b9c0de46e58f18377e642a471517a0dbf5eb547070a38c6ecf84ec8e030f650a6cee010871cd7a466a32534adda'
'9d27d97f172a503f5b7044480a0b9ccc0c4ed5dbb2eb3b2b1aa929332c3bcfe38ef0c0310b6566f23b34f9c05b77035221164a7ab7677784c4a54664f12fca22'
'0f4efddd25256e09c42b953caeee4b93eb49ecc6eaebf02e616b4dcbfdac9860c3d8a3d1a106325b2ebc4dbc6e08ac46702abcb67a06737227ccb052aaa2a067'
'10190fba9f39a8f4b620a0829e0ba8ed63bb4dbeca712966011ee7807880d01ab2abff1a80baafeb6674db70526a473fe585db8190e864f318fc4d6068552618'
'89f9b2d3918c679ce4f76c2b10dc7fcb7e04f1925a5f92542f06891de2a123a91df7eb67fd4ce71506a8132f5440b3560b7bb667e1c1813944b115c1dfe35e3f'
'b993a42c5534582631f7b379d54f6abc37e3aaa56ecf869a6d86ff14ae5a52628f4e447b6a30751bc1c14c30cec63a5c6d0aa268362d235ed477b639cac3a219'
'68478403433aafc91a03fda5d83813d2ed1dfc6ab7416b2927a803314ecf826edcb6c659587e74df65de3ccb1edf958522f56ff9ac461a1f696b6dede1d4dd35'
'ba793341c565bc4ef65be888608bebed1805f0b3fc1242f9624d65f36dace3361536e5e782ffdd76346492d8cee74864f7200f15d51352de094d7e3998ff76c0')
validpgpkeys=(
'63CDA1E5D3FC22B998D20DD6327F26951A015CC4' # Lennart Poettering
)
_backports=(
'843d5baf6aad6c53fc00ea8d95d83209a4f92de1' # core: don't use the unified hierarchy for the systemd cgroup yet (#4628)
'abd67ce74858491565cde157c7b08fda43d3279c' # basic/virt: fix userns check on CONFIG_USER_NS=n kernel (#4651)
'4318abe8d26e969ebdb97744a63ab900233a0185' # build-sys: do not install ctrl-alt-del.target symlink twice
'd112eae7da77899be245ab52aa1747d4675549f1' # device: Avoid calling unit_free(NULL) in device setup logic (#4748)
'cfed63f60dd7412c199652825ed172c319b02b3c' # nspawn: fix exit code for --help and --version (#4609)
'3099caf2b5bb9498b1d0227c40926435ca81f26f' # journal: make sure to initially populate the space info cache (#4807)
'3d4cf7de48a74726694abbaa09f9804b845ff3ba' # build-sys: check for lz4 in the old and new numbering scheme (#4717)
'db848813bae4d28c524b3b6a7dad135e426659ce' # resolved: simplify alloc size calculation (CVE-2017-9445)
'88795538726a5bbfd9efc13d441cb05e1d7fc139' # resolved: do not allocate packets with minimum size
'64a21fdaca7c93f1c30b21f6fdbd2261798b161a' # resolved: define various packet sizes as unsigned
'322e6f830c9b1f6fab5cbd9b7dd26b2787fb7d5d' # build-sys: add check for gperf lookup function signature
'24dea47a4e7ca1770cfaa408fad18ac55ed794be' # sparse: avoid clash with __bitwise and __force from 4.10 linux/types.h
)
_validate_tag() {
local success fingerprint trusted status tag=v$pkgver
parse_gpg_statusfile /dev/stdin < <(git verify-tag --raw "$tag" 2>&1)
if (( ! success )); then
error 'failed to validate tag %s\n' "$tag"
return 1
fi
if ! in_array "$fingerprint" "${validpgpkeys[@]}" && (( ! trusted )); then
error 'unknown or untrusted public key: %s\n' "$fingerprint"
return 1
fi
case $status in
'expired')
warning 'the signature has expired'
;;
'expiredkey')
warning 'the key has expired'
;;
esac
return 0
}
prepare() {
cd "$pkgbase"
_validate_tag || return
if (( ${#_backports[*]} > 0 )); then
git cherry-pick -n "${_backports[@]}"
fi
# https://github.com/systemd/systemd/issues/4789
patch -Np1 <../0001-nspawn-don-t-hide-bind-tmp-mounts.patch
# these patches aren't upstream, but they make v232 more useable.
# https://github.com/systemd/systemd/issues/4575
patch -Np1 <../0001-disable-RestrictAddressFamilies-on-i686.patch
# https://github.com/systemd/systemd/issues/4595
# https://github.com/systemd/systemd/issues/3826
patch -Np1 <../0001-Revert-nspawn-try-to-bind-mount-resolved-s-resolv.co.patch
# modification of 751ca3f test-resolved-packet: add a simple test for our allocation functions
patch -Np1 <../0001-test-resolved-packet-add-a-simple-test-for-our-alloc.patch
./autogen.sh
}
build() {
cd "$pkgbase"
local timeservers=({0..3}.arch.pool.ntp.org)
local configure_options=(
--libexecdir=/usr/lib
--localstatedir=/var
--sysconfdir=/etc
--enable-lz4
--enable-gnuefi
--disable-audit
--disable-ima
--with-sysvinit-path=
--with-sysvrcnd-path=
--with-ntp-servers="${timeservers[*]}"
--with-default-dnssec=no
--with-dbuspolicydir=/usr/share/dbus-1/system.d
--without-kill-user-processes
)
./configure "${configure_options[@]}"
make
}
package_systemd() {
pkgdesc="system and service manager"
license=('GPL2' 'LGPL2.1')
depends=('acl' 'bash' 'dbus' 'iptables' 'kbd' 'kmod' 'hwids' 'libcap'
'libgcrypt' 'libsystemd' 'libidn' 'lz4' 'pam' 'libelf' 'libseccomp'
'util-linux' 'xz')
provides=('nss-myhostname' "systemd-tools=$pkgver" "udev=$pkgver")
replaces=('nss-myhostname' 'systemd-tools' 'udev')
conflicts=('nss-myhostname' 'systemd-tools' 'udev')
optdepends=('cryptsetup: required for encrypted block devices'
'libmicrohttpd: remote journald capabilities'
'quota-tools: kernel-level quota management'
'systemd-sysvcompat: symlink package to provide sysvinit binaries'
'polkit: allow administration as unprivileged user')
backup=(etc/pam.d/systemd-user
etc/systemd/coredump.conf
etc/systemd/journald.conf
etc/systemd/journal-remote.conf
etc/systemd/journal-upload.conf
etc/systemd/logind.conf
etc/systemd/system.conf
etc/systemd/timesyncd.conf
etc/systemd/resolved.conf
etc/systemd/user.conf
etc/udev/udev.conf)
install="systemd.install"
make -C "$pkgbase" DESTDIR="$pkgdir" install
# don't write units to /etc by default. some of these will be re-enabled on
# post_install.
rm -r "$pkgdir/etc/systemd/system/"*.wants
# get rid of RPM macros
rm -r "$pkgdir/usr/lib/rpm"
# add back tmpfiles.d/legacy.conf
install -m644 "$pkgbase/tmpfiles.d/legacy.conf" "$pkgdir/usr/lib/tmpfiles.d"
# Replace dialout/tape/cdrom group in rules with uucp/storage/optical group
sed -i 's#GROUP="dialout"#GROUP="uucp"#g;
s#GROUP="tape"#GROUP="storage"#g;
s#GROUP="cdrom"#GROUP="optical"#g' "$pkgdir"/usr/lib/udev/rules.d/*.rules
sed -i 's/dialout/uucp/g;
s/tape/storage/g;
s/cdrom/optical/g' "$pkgdir"/usr/lib/sysusers.d/basic.conf
# add mkinitcpio hooks
install -Dm644 "$srcdir/initcpio-install-systemd" "$pkgdir/usr/lib/initcpio/install/systemd"
install -Dm644 "$srcdir/initcpio-install-udev" "$pkgdir/usr/lib/initcpio/install/udev"
install -Dm644 "$srcdir/initcpio-hook-udev" "$pkgdir/usr/lib/initcpio/hooks/udev"
# ensure proper permissions for /var/log/journal. This is only to placate
chown root:systemd-journal "$pkgdir/var/log/journal"
chmod 2755 "$pkgdir/var/log/journal"
# we'll create this on installation
rmdir "$pkgdir/var/log/journal/remote"
# ship default policy to leave services disabled
echo 'disable *' >"$pkgdir"/usr/lib/systemd/system-preset/99-default.preset
### manpages shipped with systemd-sysvcompat
rm "$pkgdir"/usr/share/man/man8/{telinit,halt,reboot,poweroff,runlevel,shutdown}.8
### runtime libraries shipped with libsystemd
rm "$pkgdir"/usr/lib/lib{nss,systemd,udev}*.so*
# add example bootctl configuration
install -Dm644 "$srcdir/arch.conf" "$pkgdir"/usr/share/systemd/bootctl/arch.conf
install -Dm644 "$srcdir/loader.conf" "$pkgdir"/usr/share/systemd/bootctl/loader.conf
install -Dm644 "$srcdir/splash-arch.bmp" "$pkgdir"/usr/share/systemd/bootctl/splash-arch.bmp
install -Dm644 "$srcdir/systemd-hwdb.hook" "$pkgdir/usr/share/libalpm/hooks/systemd-hwdb.hook"
install -Dm644 "$srcdir/systemd-sysusers.hook" "$pkgdir/usr/share/libalpm/hooks/systemd-sysusers.hook"
install -Dm644 "$srcdir/systemd-tmpfiles.hook" "$pkgdir/usr/share/libalpm/hooks/systemd-tmpfiles.hook"
install -Dm644 "$srcdir/systemd-update.hook" "$pkgdir/usr/share/libalpm/hooks/systemd-update.hook"
# overwrite the systemd-user PAM configuration with our own
install -Dm644 systemd-user.pam "$pkgdir/etc/pam.d/systemd-user"
}
package_libsystemd() {
pkgdesc="systemd client libraries"
depends=('glibc' 'libcap' 'libgcrypt' 'lz4' 'xz')
license=('GPL2')
provides=('libsystemd.so' 'libudev.so')
make -C "$pkgbase" DESTDIR="$pkgdir" install-rootlibLTLIBRARIES
}
package_systemd-sysvcompat() {
pkgdesc="sysvinit compat for systemd"
license=('GPL2')
groups=('base')
conflicts=('sysvinit')
depends=('systemd')
install -dm755 "$pkgdir"/usr/share/man/man8
cp -d --no-preserve=ownership,timestamp \
"$pkgbase"/man/{telinit,halt,reboot,poweroff,runlevel,shutdown}.8 \
"$pkgdir"/usr/share/man/man8
install -dm755 "$pkgdir/usr/bin"
for tool in runlevel reboot shutdown poweroff halt telinit; do
ln -s 'systemctl' "$pkgdir/usr/bin/$tool"
done
ln -s '../lib/systemd/systemd' "$pkgdir/usr/bin/init"
}
# vim: ft=sh syn=sh et
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