The source check of a new logical or NFS pool accepted only letters,
digits and "/", which refused paths such as /dev/mapper/vg0-data,
/dev/disk/by-id/wwn-..., /dev/disk/by-path/pci-0000:00:1f.2-ata-1 or
/export/vm_images. The target check let any first character but "-"
through, so a quote, "<" or "&" reached the pool XML and libvirt failed
on it.
Target and source now share one expression: letters, digits, "/", "_",
".", ":" and "-" (not first, not right after "/"), still in linear time.
The Vagrant computes' NFS export becomes /srv/wvc-nfs, created through the
page in the live pool test.
The expression that checks a storage pool's target directory nested a
repetition inside another, so a crafted target backtracked
exponentially: "," followed by 22 dashes and "!" took 1.3 s, and every
two more characters four times as long. The field allows 100
characters, so one form post could hold a worker for good (CodeQL
py/redos; the page is for superusers).
The new expression has no nested repetition and accepts exactly the
same targets: compared with the old one on 200,000 random strings over
letters, digits, "/", ".", "-", "_", ",", "!", space and newline, they
agree on every string. A crafted 100-character target is now checked
in microseconds. The tests pin the accepted and refused targets and
time the crafted one.
