c84f43d63f
It provides an ASLR-bypassing target with usable ROP gadgets.
Signed-off-by: Ian Campbell <ian.campbell@docker.com>
(cherry picked from commit 49dcce7ba0)
Signed-off-by: Victor Vieux <vieux@docker.com>
354 lines
9.7 KiB
Bash
Executable file
354 lines
9.7 KiB
Bash
Executable file
#!/usr/bin/env bash
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set -e
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EXITCODE=0
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# bits of this were adapted from lxc-checkconfig
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# see also https://github.com/lxc/lxc/blob/lxc-1.0.2/src/lxc/lxc-checkconfig.in
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possibleConfigs=(
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'/proc/config.gz'
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"/boot/config-$(uname -r)"
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"/usr/src/linux-$(uname -r)/.config"
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'/usr/src/linux/.config'
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)
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if [ $# -gt 0 ]; then
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CONFIG="$1"
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else
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: ${CONFIG:="${possibleConfigs[0]}"}
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fi
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if ! command -v zgrep &> /dev/null; then
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zgrep() {
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zcat "$2" | grep "$1"
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}
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fi
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kernelVersion="$(uname -r)"
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kernelMajor="${kernelVersion%%.*}"
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kernelMinor="${kernelVersion#$kernelMajor.}"
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kernelMinor="${kernelMinor%%.*}"
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is_set() {
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zgrep "CONFIG_$1=[y|m]" "$CONFIG" > /dev/null
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}
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is_set_in_kernel() {
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zgrep "CONFIG_$1=y" "$CONFIG" > /dev/null
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}
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is_set_as_module() {
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zgrep "CONFIG_$1=m" "$CONFIG" > /dev/null
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}
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color() {
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local codes=()
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if [ "$1" = 'bold' ]; then
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codes=( "${codes[@]}" '1' )
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shift
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fi
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if [ "$#" -gt 0 ]; then
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local code=
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case "$1" in
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# see https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
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black) code=30 ;;
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red) code=31 ;;
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green) code=32 ;;
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yellow) code=33 ;;
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blue) code=34 ;;
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magenta) code=35 ;;
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cyan) code=36 ;;
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white) code=37 ;;
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esac
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if [ "$code" ]; then
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codes=( "${codes[@]}" "$code" )
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fi
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fi
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local IFS=';'
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echo -en '\033['"${codes[*]}"'m'
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}
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wrap_color() {
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text="$1"
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shift
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color "$@"
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echo -n "$text"
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color reset
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echo
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}
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wrap_good() {
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echo "$(wrap_color "$1" white): $(wrap_color "$2" green)"
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}
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wrap_bad() {
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echo "$(wrap_color "$1" bold): $(wrap_color "$2" bold red)"
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}
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wrap_warning() {
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wrap_color >&2 "$*" red
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}
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check_flag() {
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if is_set_in_kernel "$1"; then
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wrap_good "CONFIG_$1" 'enabled'
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elif is_set_as_module "$1"; then
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wrap_good "CONFIG_$1" 'enabled (as module)'
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else
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wrap_bad "CONFIG_$1" 'missing'
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EXITCODE=1
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fi
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}
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check_flags() {
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for flag in "$@"; do
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echo -n "- "; check_flag "$flag"
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done
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}
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check_command() {
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if command -v "$1" >/dev/null 2>&1; then
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wrap_good "$1 command" 'available'
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else
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wrap_bad "$1 command" 'missing'
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EXITCODE=1
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fi
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}
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check_device() {
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if [ -c "$1" ]; then
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wrap_good "$1" 'present'
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else
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wrap_bad "$1" 'missing'
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EXITCODE=1
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fi
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}
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check_distro_userns() {
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source /etc/os-release 2>/dev/null || /bin/true
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if [[ "${ID}" =~ ^(centos|rhel)$ && "${VERSION_ID}" =~ ^7 ]]; then
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# this is a CentOS7 or RHEL7 system
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grep -q "user_namespace.enable=1" /proc/cmdline || {
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# no user namespace support enabled
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wrap_bad " (RHEL7/CentOS7" "User namespaces disabled; add 'user_namespace.enable=1' to boot command line)"
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EXITCODE=1
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}
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fi
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}
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if [ ! -e "$CONFIG" ]; then
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wrap_warning "warning: $CONFIG does not exist, searching other paths for kernel config ..."
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for tryConfig in "${possibleConfigs[@]}"; do
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if [ -e "$tryConfig" ]; then
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CONFIG="$tryConfig"
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break
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fi
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done
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if [ ! -e "$CONFIG" ]; then
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wrap_warning "error: cannot find kernel config"
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wrap_warning " try running this script again, specifying the kernel config:"
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wrap_warning " CONFIG=/path/to/kernel/.config $0 or $0 /path/to/kernel/.config"
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exit 1
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fi
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fi
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wrap_color "info: reading kernel config from $CONFIG ..." white
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echo
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echo 'Generally Necessary:'
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echo -n '- '
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cgroupSubsystemDir="$(awk '/[, ](cpu|cpuacct|cpuset|devices|freezer|memory)[, ]/ && $3 == "cgroup" { print $2 }' /proc/mounts | head -n1)"
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cgroupDir="$(dirname "$cgroupSubsystemDir")"
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if [ -d "$cgroupDir/cpu" -o -d "$cgroupDir/cpuacct" -o -d "$cgroupDir/cpuset" -o -d "$cgroupDir/devices" -o -d "$cgroupDir/freezer" -o -d "$cgroupDir/memory" ]; then
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echo "$(wrap_good 'cgroup hierarchy' 'properly mounted') [$cgroupDir]"
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else
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if [ "$cgroupSubsystemDir" ]; then
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echo "$(wrap_bad 'cgroup hierarchy' 'single mountpoint!') [$cgroupSubsystemDir]"
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else
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echo "$(wrap_bad 'cgroup hierarchy' 'nonexistent??')"
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fi
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EXITCODE=1
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echo " $(wrap_color '(see https://github.com/tianon/cgroupfs-mount)' yellow)"
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fi
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if [ "$(cat /sys/module/apparmor/parameters/enabled 2>/dev/null)" = 'Y' ]; then
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echo -n '- '
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if command -v apparmor_parser &> /dev/null; then
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echo "$(wrap_good 'apparmor' 'enabled and tools installed')"
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else
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echo "$(wrap_bad 'apparmor' 'enabled, but apparmor_parser missing')"
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echo -n ' '
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if command -v apt-get &> /dev/null; then
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echo "$(wrap_color '(use "apt-get install apparmor" to fix this)')"
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elif command -v yum &> /dev/null; then
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echo "$(wrap_color '(your best bet is "yum install apparmor-parser")')"
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else
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echo "$(wrap_color '(look for an "apparmor" package for your distribution)')"
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fi
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EXITCODE=1
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fi
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fi
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flags=(
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NAMESPACES {NET,PID,IPC,UTS}_NS
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CGROUPS CGROUP_CPUACCT CGROUP_DEVICE CGROUP_FREEZER CGROUP_SCHED CPUSETS MEMCG
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KEYS
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VETH BRIDGE BRIDGE_NETFILTER
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NF_NAT_IPV4 IP_NF_FILTER IP_NF_TARGET_MASQUERADE
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NETFILTER_XT_MATCH_{ADDRTYPE,CONNTRACK,IPVS}
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IP_NF_NAT NF_NAT NF_NAT_NEEDED
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# required for bind-mounting /dev/mqueue into containers
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POSIX_MQUEUE
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)
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check_flags "${flags[@]}"
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if [ "$kernelMajor" -lt 4 ] || [ "$kernelMajor" -eq 4 -a "$kernelMinor" -lt 8 ]; then
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check_flags DEVPTS_MULTIPLE_INSTANCES
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fi
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echo
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echo 'Optional Features:'
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{
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check_flags USER_NS
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check_distro_userns
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}
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{
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check_flags SECCOMP
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}
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{
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check_flags CGROUP_PIDS
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}
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{
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check_flags MEMCG_SWAP MEMCG_SWAP_ENABLED
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if is_set MEMCG_SWAP && ! is_set MEMCG_SWAP_ENABLED; then
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echo " $(wrap_color '(note that cgroup swap accounting is not enabled in your kernel config, you can enable it by setting boot option "swapaccount=1")' bold black)"
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fi
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}
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{
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if is_set LEGACY_VSYSCALL_NATIVE; then
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echo -n "- "; wrap_bad "CONFIG_LEGACY_VSYSCALL_NATIVE" 'enabled'
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echo " $(wrap_color '(dangerous, provides an ASLR-bypassing target with usable ROP gadgets.)' bold black)"
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elif is_set LEGACY_VSYSCALL_EMULATE; then
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echo -n "- "; wrap_good "CONFIG_LEGACY_VSYSCALL_EMULATE" 'enabled'
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elif is_set LEGACY_VSYSCALL_NONE; then
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echo -n "- "; wrap_bad "CONFIG_LEGACY_VSYSCALL_NONE" 'enabled'
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echo " $(wrap_color '(containers using eglibc <= 2.13 will not work. Switch to' bold black)"
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echo " $(wrap_color ' "CONFIG_VSYSCALL_[NATIVE|EMULATE]" or use "vsyscall=[native|emulate]"' bold black)"
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echo " $(wrap_color ' on kernel command line. Note that this will disable ASLR for the,' bold black)"
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echo " $(wrap_color ' VDSO which may assist in exploiting security vulnerabilities.)' bold black)"
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# else Older kernels (prior to 3dc33bd30f3e, released in v4.40-rc1) do
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# not have these LEGACY_VSYSCALL options and are effectively
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# LEGACY_VSYSCALL_EMULATE. Even older kernels are presumably
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# effectively LEGACY_VSYSCALL_NATIVE.
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fi
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}
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if [ "$kernelMajor" -lt 4 ] || [ "$kernelMajor" -eq 4 -a "$kernelMinor" -le 5 ]; then
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check_flags MEMCG_KMEM
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fi
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if [ "$kernelMajor" -lt 3 ] || [ "$kernelMajor" -eq 3 -a "$kernelMinor" -le 18 ]; then
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check_flags RESOURCE_COUNTERS
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fi
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if [ "$kernelMajor" -lt 3 ] || [ "$kernelMajor" -eq 3 -a "$kernelMinor" -le 13 ]; then
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netprio=NETPRIO_CGROUP
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else
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netprio=CGROUP_NET_PRIO
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fi
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flags=(
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BLK_CGROUP BLK_DEV_THROTTLING IOSCHED_CFQ CFQ_GROUP_IOSCHED
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CGROUP_PERF
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CGROUP_HUGETLB
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NET_CLS_CGROUP $netprio
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CFS_BANDWIDTH FAIR_GROUP_SCHED RT_GROUP_SCHED
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IP_VS
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IP_VS_NFCT
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IP_VS_RR
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)
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check_flags "${flags[@]}"
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if ! is_set EXT4_USE_FOR_EXT2; then
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check_flags EXT3_FS EXT3_FS_XATTR EXT3_FS_POSIX_ACL EXT3_FS_SECURITY
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if ! is_set EXT3_FS || ! is_set EXT3_FS_XATTR || ! is_set EXT3_FS_POSIX_ACL || ! is_set EXT3_FS_SECURITY; then
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echo " $(wrap_color '(enable these ext3 configs if you are using ext3 as backing filesystem)' bold black)"
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fi
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fi
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check_flags EXT4_FS EXT4_FS_POSIX_ACL EXT4_FS_SECURITY
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if ! is_set EXT4_FS || ! is_set EXT4_FS_POSIX_ACL || ! is_set EXT4_FS_SECURITY; then
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if is_set EXT4_USE_FOR_EXT2; then
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echo " $(wrap_color 'enable these ext4 configs if you are using ext3 or ext4 as backing filesystem' bold black)"
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else
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echo " $(wrap_color 'enable these ext4 configs if you are using ext4 as backing filesystem' bold black)"
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fi
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fi
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echo '- Network Drivers:'
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echo ' - "'$(wrap_color 'overlay' blue)'":'
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check_flags VXLAN | sed 's/^/ /'
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echo ' Optional (for encrypted networks):'
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check_flags CRYPTO CRYPTO_AEAD CRYPTO_GCM CRYPTO_SEQIV CRYPTO_GHASH \
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XFRM XFRM_USER XFRM_ALGO INET_ESP INET_XFRM_MODE_TRANSPORT | sed 's/^/ /'
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echo ' - "'$(wrap_color 'ipvlan' blue)'":'
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check_flags IPVLAN | sed 's/^/ /'
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echo ' - "'$(wrap_color 'macvlan' blue)'":'
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check_flags MACVLAN DUMMY | sed 's/^/ /'
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# only fail if no storage drivers available
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CODE=${EXITCODE}
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EXITCODE=0
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STORAGE=1
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echo '- Storage Drivers:'
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echo ' - "'$(wrap_color 'aufs' blue)'":'
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check_flags AUFS_FS | sed 's/^/ /'
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if ! is_set AUFS_FS && grep -q aufs /proc/filesystems; then
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echo " $(wrap_color '(note that some kernels include AUFS patches but not the AUFS_FS flag)' bold black)"
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fi
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[ "$EXITCODE" = 0 ] && STORAGE=0
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EXITCODE=0
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echo ' - "'$(wrap_color 'btrfs' blue)'":'
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check_flags BTRFS_FS | sed 's/^/ /'
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check_flags BTRFS_FS_POSIX_ACL | sed 's/^/ /'
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[ "$EXITCODE" = 0 ] && STORAGE=0
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EXITCODE=0
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echo ' - "'$(wrap_color 'devicemapper' blue)'":'
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check_flags BLK_DEV_DM DM_THIN_PROVISIONING | sed 's/^/ /'
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[ "$EXITCODE" = 0 ] && STORAGE=0
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EXITCODE=0
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echo ' - "'$(wrap_color 'overlay' blue)'":'
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check_flags OVERLAY_FS | sed 's/^/ /'
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[ "$EXITCODE" = 0 ] && STORAGE=0
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EXITCODE=0
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echo ' - "'$(wrap_color 'zfs' blue)'":'
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echo -n " - "; check_device /dev/zfs
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echo -n " - "; check_command zfs
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echo -n " - "; check_command zpool
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[ "$EXITCODE" = 0 ] && STORAGE=0
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EXITCODE=0
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EXITCODE=$CODE
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[ "$STORAGE" = 1 ] && EXITCODE=1
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echo
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check_limit_over()
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{
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if [ $(cat "$1") -le "$2" ]; then
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wrap_bad "- $1" "$(cat $1)"
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wrap_color " This should be set to at least $2, for example set: sysctl -w kernel/keys/root_maxkeys=1000000" bold black
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EXITCODE=1
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else
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wrap_good "- $1" "$(cat $1)"
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fi
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}
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echo 'Limits:'
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check_limit_over /proc/sys/kernel/keys/root_maxkeys 10000
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echo
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exit $EXITCODE
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