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Check file permissions before loading them #76

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Merged
onnozweers merged 1 commit into from
Mar 12, 2025
Merged

Check file permissions before loading them #76

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36 changes: 35 additions & 1 deletion ada/ada
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Original file line number Diff line number Diff line change
Expand Up @@ -257,6 +257,22 @@ usage() {
exit 1
}


get_permissions () {
# Returns the access permissions of a file in 'drwxrwxrwx' format.
local file="$1"
case $OSTYPE in
darwin* ) permissions=$(stat -f "%Sp" "$file" | grep -o '^..........$' ) ;;
* ) permissions=$(stat --format='%A' "$file" | grep -o '^..........$' ) ;;
esac
if [ -z "$permissions" ] ; then
echo 1>&2 "ERROR: Could not check permissions of file '$file'."
exit 1
fi
echo "$permissions"
}


#
# Set default values and initialize variables
#
Expand Down Expand Up @@ -302,6 +318,12 @@ set_defaults() {
declare -a configfiles=( "${script_dir}"/etc/ada.conf /etc/ada.conf ~/.ada/ada.conf )
for configfile in "${configfiles[@]}" ; do
if [ -f "$configfile" ] ; then
# Before loading, check permissions. Source file must never be world writable!
permissions=$(get_permissions "$configfile") || exit 1
if grep '^........w.$' <<<"$permissions" ; then
echo 1>&2 "ERROR: Config file '$configfile' is world writable. This is a security risk."
exit 1
fi
source "$configfile"
fi
done
Expand Down Expand Up @@ -1734,7 +1756,19 @@ validate_input() {
echo 1>&2 "ERROR: specified tokenfile does not exist."
exit 1
fi

# Tokenfile must never be world readable or writable!
if get_permissions "$tokenfile" | grep '^........w.$' ; then
echo 1>&2 "ERROR: Tokenfile '$tokenfile' is world writable." \
"This may be unsafe on shared systems. Use chmod to change the permissions."
exit 1
fi
if get_permissions "$tokenfile" | grep '^.......r..$' ; then
echo 1>&2 "ERROR: Tokenfile '$tokenfile' is world readable." \
"This may be unsafe on shared systems. Use chmod to change the permissions."
exit 1
fi
#
# First, we assume the tokenfile is an Rclone config file.
token=$(sed -n 's/^bearer_token *= *//p' "$tokenfile")
if [ "$(wc -l <<<"$token")" -gt 1 ] ; then
echo 1>&2 "ERROR: file '$tokenfile' contains multiple tokens."
Expand Down