Entry names read from a squashfs directory are not sanitized by
go-diskfs. The squashfs backend joined each leaf name onto its
directory to form the object's remote, so a crafted image could escape
its directory.
Use sanitize.Leaf to skip unsafe entries in List. A "\" is an
ordinary character in a file name on the systems squashfs images are
made on and in an rclone remote path, so it is deliberately not
rejected; making it safe for the destination is the destination
backend's job.
Skipped entries are logged at DEBUG with a single NOTICE count per
listing so a crafted image under a mount cannot flood the log.
(cherry picked from commit 63385c66175141b63bb53b3e42b50908649f8437)
Nick Craig-Wood
ad8cd41c49