1. #!/usr/bin/env bash
    2. set -e
    3. EXITCODE=0
    4. # bits of this were adapted from lxc-checkconfig
    5. # see also https://github.com/lxc/lxc/blob/lxc-1.0.2/src/lxc/lxc-checkconfig.in
    6. possibleConfigs=(
    7.     '/proc/config.gz'
    8.     "/boot/config-$(uname -r)"
    9.     "/usr/src/linux-$(uname -r)/.config"
    10.     '/usr/src/linux/.config'
    11. )
    12. if [ $# -gt 0 ]; then
    13.     CONFIG="$1"
    14. else
    15.     : "${CONFIG:="${possibleConfigs[0]}"}"
    16. fi
    17. if ! command -v zgrep &>/dev/null; then
    18.     zgrep() {
    19.         zcat "$2" | grep "$1"
    20.     }
    21. fi
    22. kernelVersion="$(uname -r)"
    23. kernelMajor="${kernelVersion%%.*}"
    24. kernelMinor="${kernelVersion#$kernelMajor.}"
    25. kernelMinor="${kernelMinor%%.*}"
    26. is_set() {
    27.     zgrep "CONFIG_$1=[y|m]" "$CONFIG" >/dev/null
    28. }
    29. is_set_in_kernel() {
    30.     zgrep "CONFIG_$1=y" "$CONFIG" >/dev/null
    31. }
    32. is_set_as_module() {
    33.     zgrep "CONFIG_$1=m" "$CONFIG" >/dev/null
    34. }
    35. color() {
    36.     local codes=()
    37.     if [ "$1" = 'bold' ]; then
    38.         codes=("${codes[@]}" '1')
    39.         shift
    40.     fi
    41.     if [ "$#" -gt 0 ]; then
    42.         local code=
    43.         case "$1" in
    44.         # see https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
    45.         black) code=30 ;;
    46.         red) code=31 ;;
    47.         green) code=32 ;;
    48.         yellow) code=33 ;;
    49.         blue) code=34 ;;
    50.         magenta) code=35 ;;
    51.         cyan) code=36 ;;
    52.         white) code=37 ;;
    53.         esac
    54.         if [ "$code" ]; then
    55.             codes=("${codes[@]}" "$code")
    56.         fi
    57.     fi
    58.     local IFS=';'
    59.     echo -en '\033['"${codes[*]}"'m'
    60. }
    61. wrap_color() {
    62.     text="$1"
    63.     shift
    64.     color "$@"
    65.     echo -n "$text"
    66.     color reset
    67.     echo
    68. }
    69. wrap_good() {
    70.     echo "$(wrap_color "$1" white): $(wrap_color "$2" green)"
    71. }
    72. wrap_bad() {
    73.     echo "$(wrap_color "$1" bold): $(wrap_color "$2" bold red)"
    74. }
    75. wrap_warning() {
    76.     wrap_color >&2 "$*" red
    77. }
    78. check_flag() {
    79.     if is_set_in_kernel "$1"; then
    80.         wrap_good "CONFIG_$1" 'enabled'
    81.     elif is_set_as_module "$1"; then
    82.         wrap_good "CONFIG_$1" 'enabled (as module)'
    83.     else
    84.         wrap_bad "CONFIG_$1" 'missing'
    85.         EXITCODE=1
    86.     fi
    87. }
    88. check_flags() {
    89.     for flag in "$@"; do
    90.         echo -n "- "
    91.         check_flag "$flag"
    92.     done
    93. }
    94. check_command() {
    95.     if command -v "$1" >/dev/null 2>&1; then
    96.         wrap_good "$1 command" 'available'
    97.     else
    98.         wrap_bad "$1 command" 'missing'
    99.         EXITCODE=1
    100.     fi
    101. }
    102. check_device() {
    103.     if [ -c "$1" ]; then
    104.         wrap_good "$1" 'present'
    105.     else
    106.         wrap_bad "$1" 'missing'
    107.         EXITCODE=1
    108.     fi
    109. }
    110. check_distro_userns() {
    111.     source /etc/os-release 2>/dev/null || /bin/true
    112.     if [[ "${ID}" =~ ^(centos|rhel)$ && "${VERSION_ID}" =~ ^7 ]]; then
    113.         # this is a CentOS7 or RHEL7 system
    114.         grep -q "user_namespace.enable=1" /proc/cmdline || {
    115.             # no user namespace support enabled
    116.             wrap_bad "  (RHEL7/CentOS7" "User namespaces disabled; add 'user_namespace.enable=1' to boot command line)"
    117.             EXITCODE=1
    118.         }
    119.     fi
    120. }
    121. if [ ! -e "$CONFIG" ]; then
    122.     wrap_warning "warning: $CONFIG does not exist, searching other paths for kernel config ..."
    123.     for tryConfig in "${possibleConfigs[@]}"; do
    124.         if [ -e "$tryConfig" ]; then
    125.             CONFIG="$tryConfig"
    126.             break
    127.         fi
    128.     done
    129.     if [ ! -e "$CONFIG" ]; then
    130.         wrap_warning "error: cannot find kernel config"
    131.         wrap_warning "  try running this script again, specifying the kernel config:"
    132.         wrap_warning "    CONFIG=/path/to/kernel/.config $0 or $0 /path/to/kernel/.config"
    133.         exit 1
    134.     fi
    135. fi
    136. wrap_color "info: reading kernel config from $CONFIG ..." white
    137. echo
    138. echo 'Generally Necessary:'
    139. echo -n '- '
    140. cgroupSubsystemDir="$(awk '/[, ](cpu|cpuacct|cpuset|devices|freezer|memory)[, ]/ && $3 == "cgroup" { print $2 }' /proc/mounts | head -n1)"
    141. cgroupDir="$(dirname "$cgroupSubsystemDir")"
    142. if [ -d "$cgroupDir/cpu" ] || [ -d "$cgroupDir/cpuacct" ] || [ -d "$cgroupDir/cpuset" ] || [ -d "$cgroupDir/devices" ] || [ -d "$cgroupDir/freezer" ] || [ -d "$cgroupDir/memory" ]; then
    143.     echo "$(wrap_good 'cgroup hierarchy' 'properly mounted') [$cgroupDir]"
    144. else
    145.     if [ "$cgroupSubsystemDir" ]; then
    146.         echo "$(wrap_bad 'cgroup hierarchy' 'single mountpoint!') [$cgroupSubsystemDir]"
    147.     else
    148.         wrap_bad 'cgroup hierarchy' 'nonexistent??'
    149.     fi
    150.     EXITCODE=1
    151.     echo "    $(wrap_color '(see https://github.com/tianon/cgroupfs-mount)' yellow)"
    152. fi
    153. if [ "$(cat /sys/module/apparmor/parameters/enabled 2>/dev/null)" = 'Y' ]; then
    154.     echo -n '- '
    155.     if command -v apparmor_parser &>/dev/null; then
    156.         wrap_good 'apparmor' 'enabled and tools installed'
    157.     else
    158.         wrap_bad 'apparmor' 'enabled, but apparmor_parser missing'
    159.         echo -n '    '
    160.         if command -v apt-get &>/dev/null; then
    161.             wrap_color '(use "apt-get install apparmor" to fix this)'
    162.         elif command -v yum &>/dev/null; then
    163.             wrap_color '(your best bet is "yum install apparmor-parser")'
    164.         else
    165.             wrap_color '(look for an "apparmor" package for your distribution)'
    166.         fi
    167.         EXITCODE=1
    168.     fi
    169. fi
    170. flags=(
    171.     NAMESPACES {NET,PID,IPC,UTS}_NS
    172.     CGROUPS CGROUP_CPUACCT CGROUP_DEVICE CGROUP_FREEZER CGROUP_SCHED CPUSETS MEMCG
    173.     KEYS
    174.     VETH BRIDGE BRIDGE_NETFILTER
    175.     NF_NAT_IPV4 IP_NF_FILTER IP_NF_TARGET_MASQUERADE
    176.     NETFILTER_XT_MATCH_{ADDRTYPE,CONNTRACK,IPVS}
    177.     IP_NF_NAT NF_NAT NF_NAT_NEEDED
    178.     # required for bind-mounting /dev/mqueue into containers
    179.     POSIX_MQUEUE
    180. )
    181. check_flags "${flags[@]}"
    182. if [ "$kernelMajor" -lt 4 ] || ([ "$kernelMajor" -eq 4 ] && [ "$kernelMinor" -lt 8 ]); then
    183.     check_flags DEVPTS_MULTIPLE_INSTANCES
    184. fi
    185. echo
    186. echo 'Optional Features:'
    187. {
    188.     check_flags USER_NS
    189.     check_distro_userns
    190. }
    191. {
    192.     check_flags SECCOMP
    193. }
    194. {
    195.     check_flags CGROUP_PIDS
    196. }
    197. {
    198.     CODE=${EXITCODE}
    199.     check_flags MEMCG_SWAP MEMCG_SWAP_ENABLED
    200.     if [ -e /sys/fs/cgroup/memory/memory.memsw.limit_in_bytes ]; then
    201.         echo "    $(wrap_color '(cgroup swap accounting is currently enabled)' bold black)"
    202.         EXITCODE=${CODE}
    203.     elif is_set MEMCG_SWAP && ! is_set MEMCG_SWAP_ENABLED; then
    204.         echo "    $(wrap_color '(cgroup swap accounting is currently not enabled, you can enable it by setting boot option "swapaccount=1")' bold black)"
    205.     fi
    206. }
    207. {
    208.     if is_set LEGACY_VSYSCALL_NATIVE; then
    209.         echo -n "- "
    210.         wrap_bad "CONFIG_LEGACY_VSYSCALL_NATIVE" 'enabled'
    211.         echo "    $(wrap_color '(dangerous, provides an ASLR-bypassing target with usable ROP gadgets.)' bold black)"
    212.     elif is_set LEGACY_VSYSCALL_EMULATE; then
    213.         echo -n "- "
    214.         wrap_good "CONFIG_LEGACY_VSYSCALL_EMULATE" 'enabled'
    215.     elif is_set LEGACY_VSYSCALL_NONE; then
    216.         echo -n "- "
    217.         wrap_bad "CONFIG_LEGACY_VSYSCALL_NONE" 'enabled'
    218.         echo "    $(wrap_color '(containers using eglibc <= 2.13 will not work. Switch to' bold black)"
    219.         echo "    $(wrap_color ' "CONFIG_VSYSCALL_[NATIVE|EMULATE]" or use "vsyscall=[native|emulate]"' bold black)"
    220.         echo "    $(wrap_color ' on kernel command line. Note that this will disable ASLR for the,' bold black)"
    221.         echo "    $(wrap_color ' VDSO which may assist in exploiting security vulnerabilities.)' bold black)"
    222.     # else Older kernels (prior to 3dc33bd30f3e, released in v4.40-rc1) do
    223.     #      not have these LEGACY_VSYSCALL options and are effectively
    224.     #      LEGACY_VSYSCALL_EMULATE. Even older kernels are presumably
    225.     #      effectively LEGACY_VSYSCALL_NATIVE.
    226.     fi
    227. }
    228. if [ "$kernelMajor" -lt 4 ] || ([ "$kernelMajor" -eq 4 ] && [ "$kernelMinor" -le 5 ]); then
    229.     check_flags MEMCG_KMEM
    230. fi
    231. if [ "$kernelMajor" -lt 3 ] || ([ "$kernelMajor" -eq 3 ] && [ "$kernelMinor" -le 18 ]); then
    232.     check_flags RESOURCE_COUNTERS
    233. fi
    234. if [ "$kernelMajor" -lt 3 ] || ([ "$kernelMajor" -eq 3 ] && [ "$kernelMinor" -le 13 ]); then
    235.     netprio=NETPRIO_CGROUP
    236. else
    237.     netprio=CGROUP_NET_PRIO
    238. fi
    239. flags=(
    240.     BLK_CGROUP BLK_DEV_THROTTLING IOSCHED_CFQ CFQ_GROUP_IOSCHED
    241.     CGROUP_PERF
    242.     CGROUP_HUGETLB
    243.     NET_CLS_CGROUP $netprio
    244.     CFS_BANDWIDTH FAIR_GROUP_SCHED RT_GROUP_SCHED
    245.     IP_NF_TARGET_REDIRECT
    246.     IP_VS
    247.     IP_VS_NFCT
    248.     IP_VS_PROTO_TCP
    249.     IP_VS_PROTO_UDP
    250.     IP_VS_RR
    251. )
    252. check_flags "${flags[@]}"
    253. if ! is_set EXT4_USE_FOR_EXT2; then
    254.     check_flags EXT3_FS EXT3_FS_XATTR EXT3_FS_POSIX_ACL EXT3_FS_SECURITY
    255.     if ! is_set EXT3_FS || ! is_set EXT3_FS_XATTR || ! is_set EXT3_FS_POSIX_ACL || ! is_set EXT3_FS_SECURITY; then
    256.         echo "    $(wrap_color '(enable these ext3 configs if you are using ext3 as backing filesystem)' bold black)"
    257.     fi
    258. fi
    259. check_flags EXT4_FS EXT4_FS_POSIX_ACL EXT4_FS_SECURITY
    260. if ! is_set EXT4_FS || ! is_set EXT4_FS_POSIX_ACL || ! is_set EXT4_FS_SECURITY; then
    261.     if is_set EXT4_USE_FOR_EXT2; then
    262.         echo "    $(wrap_color 'enable these ext4 configs if you are using ext3 or ext4 as backing filesystem' bold black)"
    263.     else
    264.         echo "    $(wrap_color 'enable these ext4 configs if you are using ext4 as backing filesystem' bold black)"
    265.     fi
    266. fi
    267. echo '- Network Drivers:'
    268. echo "  - \"$(wrap_color 'overlay' blue)\":"
    269. check_flags VXLAN BRIDGE_VLAN_FILTERING | sed 's/^/    /'
    270. echo '      Optional (for encrypted networks):'
    271. check_flags CRYPTO CRYPTO_AEAD CRYPTO_GCM CRYPTO_SEQIV CRYPTO_GHASH \
    272.     XFRM XFRM_USER XFRM_ALGO INET_ESP INET_XFRM_MODE_TRANSPORT | sed 's/^/      /'
    273. echo "  - \"$(wrap_color 'ipvlan' blue)\":"
    274. check_flags IPVLAN | sed 's/^/    /'
    275. echo "  - \"$(wrap_color 'macvlan' blue)\":"
    276. check_flags MACVLAN DUMMY | sed 's/^/    /'
    277. echo "  - \"$(wrap_color 'ftp,tftp client in container' blue)\":"
    278. check_flags NF_NAT_FTP NF_CONNTRACK_FTP NF_NAT_TFTP NF_CONNTRACK_TFTP | sed 's/^/    /'
    279. # only fail if no storage drivers available
    280. CODE=${EXITCODE}
    281. EXITCODE=0
    282. STORAGE=1
    283. echo '- Storage Drivers:'
    284. echo "  - \"$(wrap_color 'aufs' blue)\":"
    285. check_flags AUFS_FS | sed 's/^/    /'
    286. if ! is_set AUFS_FS && grep -q aufs /proc/filesystems; then
    287.     echo "      $(wrap_color '(note that some kernels include AUFS patches but not the AUFS_FS flag)' bold black)"
    288. fi
    289. [ "$EXITCODE" = 0 ] && STORAGE=0
    290. EXITCODE=0
    291. echo "  - \"$(wrap_color 'btrfs' blue)\":"
    292. check_flags BTRFS_FS | sed 's/^/    /'
    293. check_flags BTRFS_FS_POSIX_ACL | sed 's/^/    /'
    294. [ "$EXITCODE" = 0 ] && STORAGE=0
    295. EXITCODE=0
    296. echo "  - \"$(wrap_color 'devicemapper' blue)\":"
    297. check_flags BLK_DEV_DM DM_THIN_PROVISIONING | sed 's/^/    /'
    298. [ "$EXITCODE" = 0 ] && STORAGE=0
    299. EXITCODE=0
    300. echo "  - \"$(wrap_color 'overlay' blue)\":"
    301. check_flags OVERLAY_FS | sed 's/^/    /'
    302. [ "$EXITCODE" = 0 ] && STORAGE=0
    303. EXITCODE=0
    304. echo "  - \"$(wrap_color 'zfs' blue)\":"
    305. echo -n "    - "
    306. check_device /dev/zfs
    307. echo -n "    - "
    308. check_command zfs
    309. echo -n "    - "
    310. check_command zpool
    311. [ "$EXITCODE" = 0 ] && STORAGE=0
    312. EXITCODE=0
    313. EXITCODE=$CODE
    314. [ "$STORAGE" = 1 ] && EXITCODE=1
    315. echo
    316. check_limit_over() {
    317.     if [ "$(cat "$1")" -le "$2" ]; then
    318.         wrap_bad "- $1" "$(cat "$1")"
    319.         wrap_color "    This should be set to at least $2, for example set: sysctl -w kernel/keys/root_maxkeys=1000000" bold black
    320.         EXITCODE=1
    321.     else
    322.         wrap_good "- $1" "$(cat "$1")"
    323.     fi
    324. }
    325. echo 'Limits:'
    326. check_limit_over /proc/sys/kernel/keys/root_maxkeys 10000
    327. echo
    328. exit $EXITCODE