From 267873ac9b9e5565f1f1550c931c413f5b5dda9d Mon Sep 17 00:00:00 2001 From: Daniel Golle Date: Mon, 12 Feb 2018 23:36:54 +0100 Subject: [PATCH] base-files: don't evaluate block-device uevent Current code and also before commit da52dd0c83 was vulnerable to shell injection using volume lables in the GPT partition table of block devices. Given that partition names can be freely defined in GPT tables we really shouldn't evaluate a string which is potentially crafted with evil intentions. Hence rather use `export -n` to absorb the uevent's variables into the environment. Fixes commit da52dd0c83 (base-files: quote values when evaluating uevent) Signed-off-by: Daniel Golle [mschiffer@universe-factory.net: suggested export -n usage] --- package/base-files/files/lib/upgrade/common.sh | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/package/base-files/files/lib/upgrade/common.sh b/package/base-files/files/lib/upgrade/common.sh index 616131c89c..5f5c9dc8a3 100644 --- a/package/base-files/files/lib/upgrade/common.sh +++ b/package/base-files/files/lib/upgrade/common.sh @@ -101,7 +101,7 @@ get_magic_long() { } export_bootdevice() { - local cmdline uuid disk uevent + local cmdline uuid disk uevent line local MAJOR MINOR DEVNAME DEVTYPE if read cmdline < /proc/cmdline; then @@ -134,7 +134,9 @@ export_bootdevice() { esac if [ -e "$uevent" ]; then - eval "$(sed "s/=\(.*\)/=\'\1\'/" < "$uevent")" + while read line; do + export -n "$line" + done < "$uevent" export BOOTDEV_MAJOR=$MAJOR export BOOTDEV_MINOR=$MINOR return 0 @@ -146,10 +148,12 @@ export_bootdevice() { export_partdevice() { local var="$1" offset="$2" - local uevent MAJOR MINOR DEVNAME DEVTYPE + local uevent line MAJOR MINOR DEVNAME DEVTYPE for uevent in /sys/class/block/*/uevent; do - eval "$(sed "s/=\(.*\)/=\'\1\'/" < "$uevent")" + while read line; do + export -n "$line" + done < "$uevent" if [ $BOOTDEV_MAJOR = $MAJOR -a $(($BOOTDEV_MINOR + $offset)) = $MINOR -a -b "/dev/$DEVNAME" ]; then export "$var=$DEVNAME" return 0