The birth-time (btime) write in writeMetadataToFile followed symlinks for
any object that was not a translated link, so under -l/--links a symlink
planted by an untrusted source at the destination path could redirect the
btime write to a target outside the backup destination on OSes where
birth time is settable (Windows).
Use the NOFOLLOW birth-time write whenever translating symlinks, not only
for translated links. It is a no-op on a real file or directory and stops
a planted symlink from being followed out of the destination.
Nick Craig-Wood
215e6dbc65