134 lines
4.0 KiB
Bash
Executable File
134 lines
4.0 KiB
Bash
Executable File
#!/bin/sh
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#Hashes all files in /boot to check them during early boot
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#Exit codes: 0 = success, 1 = checksum mbr mismatch, 2 = checksum /boot mismatch,
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#3 = checksum mbr/boot mismatch, 4 = not root, 5 = no hasher found, 6 = wrong usage,
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#7 = write error, 8 = dd error
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VERSION="0.7.1"
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PATH="/bin:/usr/bin:/sbin:/usr/sbin"
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DIGEST_FILE="/var/lib/hashboot.digest"
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LOG_FILE="/tmp/hashboot.log"
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MBR_FILE="/var/lib/mbr.digest"
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MBR_TMP="/tmp/mbr"
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BACKUP_FILE="/var/cache/boot-backup.tar.gz"
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HASHER=""
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BOOT_MOUNTED=0
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#Umount /boot if we mounted it, exit with given exit code
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function die
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{
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if [ ${BOOT_MOUNTED} -gt 0 ]
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then
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umount /boot
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fi
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exit ${1}
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}
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#If we're not root: exit
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if [ ${UID} -ne 0 ]
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then
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echo "You have to be root" >&2
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die 4
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fi
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#Try different hashers, use the most secure
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HASHER=$(/usr/bin/which --skip-dot sha512sum 2> /dev/null)
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test -z ${HASHER} && HASHER=$(/usr/bin/which --skip-dot sha384sum 2> /dev/null)
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test -z ${HASHER} && HASHER=$(/usr/bin/which --skip-dot sha256sum 2> /dev/null)
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test -z ${HASHER} && HASHER=$(/usr/bin/which --skip-dot sha224sum 2> /dev/null)
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#It gets insecure below here, but better than nothing?
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test -z ${HASHER} && HASHER=$(/usr/bin/which --skip-dot sha1sum 2> /dev/null)
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test -z ${HASHER} && HASHER=$(/usr/bin/which --skip-dot md5sum 2> /dev/null)
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#If we found no hasher: exit
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if [ -z ${HASHER} ]
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then
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echo "No hash calculator found" >&2
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die 5
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fi
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#If /boot is in fstab but not mounted: mount, mark as mounted
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if grep -q '/boot.*noauto' /etc/fstab && ! grep -q /boot /etc/mtab
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then
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mount /boot
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BOOT_MOUNTED=1
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fi
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if [ "${1}" == "index" ]
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then
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#Write header
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echo "#hashboot ${VERSION} - Algorithm: $(basename ${HASHER})" > ${DIGEST_FILE}
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#Write hashes of all regular files to ${DIGEST_FILE}
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err=$(dd if=/dev/sda of=${MBR_TMP} bs=2M count=1 status=noxfer 2>&1) || die 8
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${HASHER} ${MBR_TMP} > ${MBR_FILE}
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find /boot -type f -exec ${HASHER} --binary {} >> ${DIGEST_FILE} +
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if [ $? == 0 ]
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then
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echo "List of hashes written to ${DIGEST_FILE}"
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else
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echo "Error writing ${DIGEST_FILE}" >&2
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die 7
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fi
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#Backup of good files
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tar -czpPf ${BACKUP_FILE} /boot ${MBR_TMP} ${MBR_FILE} ${DIGEST_FILE}
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if [ $? == 0 ]
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then
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echo "Backup written to ${BACKUP_FILE}"
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else
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echo "Error writing ${BACKUP_FILE}" >&2
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die 7
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fi
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elif [ "${1}" == "check" ]
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then
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COUNTER=0
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err=$(dd if=/dev/sda of=${MBR_TMP} bs=2M count=1 status=noxfer 2>&1) || die 8
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if $(${HASHER} --check --warn --quiet --strict ${MBR_FILE} > ${LOG_FILE})
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then
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echo "MBR ok"
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else
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echo " !! TIME TO PANIK: MBR WAS MODIFIED !!"
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COUNTER=$((COUNTER + 1))
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fi
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if $(${HASHER} --check --warn --quiet --strict ${DIGEST_FILE} >> ${LOG_FILE})
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then
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echo "/boot ok"
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die 0
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else
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echo " !! TIME TO PANIK: AT LEAST 1 FILE WAS MODIFIED !!"
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COUNTER=$((COUNTER + 2))
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die $COUNTER
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fi
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elif [ "${1}" == "recover" ]
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then
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echo "Restoring files from backup... (type yes or no for each file)"
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#For each failed file: ask if it should be recovered from backup
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for file in $(cut -d: -f1 ${LOG_FILE})
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do
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tar -xzpPvwf ${BACKUP_FILE} ${file}
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[ $? != 0 ] && echo "Error restoring ${file} from backup, continuing"
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# If the MBR is to be recovered, ask if it really should be copied to /dev/sda.
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# Should be no problem to do it automatically, but it is untested and would
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# be really bad if there is an error.
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if [ "$file" == ${MBR_TMP} ]
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then
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echo "Backup of MBR copied to ${MBR_TMP}, copy it to /dev/sda? (DANGEROUS) [y/N] "
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read -r yesno
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if [ "${yesno}" == "y" ]
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then
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cp ${MBR_TMP} /dev/sda
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else
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echo "MBR not recovered, you can copy it manually with:"
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echo "cp ${MBR_TMP} /dev/sda"
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fi
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fi
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done
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else
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echo "Usage: ${0} index|check|recover" >&2
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die 6
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fi
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die 0
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