io/fs: fix stack exhaustion in Glob
A limit is added to the number of path separators allowed by an input to
Glob, to prevent stack exhaustion issues.
Thanks to Juho Nurminen of Mattermost who reported a similar issue in
path/filepath.
Fixes CVE-2022-30630
Fixes golang/go#53415
Change-Id: I5a9d02591fed90cd3d52627f5945f1301e53465d
Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/
1497588
Reviewed-by: Roland Shoemaker <bracewell@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/417065
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>