The setting of errno in canonicalize() is rather fragile and seems to
be even wrong in one corner case: when the invalid path "/local/domain/"
is passed, sscanf() will set errno to 0, resulting in canonicalize() to
return NULL with errno being 0. This can result in triggering the
assert(conn->in == NULL) in consider_message().
Don't assume the initial setting of errno to "EINVAL" will stay valid
in all cases and set it to EINVAL only when returning NULL due to an
invalid path.
This is XSA-481/CVE-2026-23555
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <julien@xen.org>
Juergen Gross
4c61822b04