util-linux/Add-documentation-on-blacklisted-modules-to-mount-8-.patch

From 1ade50a36f23fc35abb465aa5b7cfc73b2476328 Mon Sep 17 00:00:00 2001
From: Martin Wilck <mwilck@suse.com>
Date: Fri, 1 Feb 2019 12:09:11 +0100
Subject: [PATCH] Add documentation on blacklisted modules to mount(8) man page

Signed-off-by: Martin Wilck <mwilck@suse.com>
---
 sys-utils/mount.8 | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/sys-utils/mount.8 b/sys-utils/mount.8
index da0ac5b..c231e12 100644
--- a/sys-utils/mount.8
+++ b/sys-utils/mount.8
@@ -338,6 +338,32 @@ The
 option is similar, with the restriction that the user must be
 member of the group of the special file.
 
+.SS Blacklisted file systems
+In the Linux kernel, file system types are implemented as kernel
+modules. While many of these file systems are well maintained,
+some of the older and less frequently used ones are not. This
+poses a security risk, because maliciously crafted file system
+images might open security holes when mounted either automatically
+or by an inadvertent user. The
+.B mount
+command prints "unsupported file system type 'somefs'" in this case,
+because it can't distinguish between a really unsupported file system
+(kernel module non-existent) and a blacklisted file system.
+
+Users who need the blacklisted file systems and therefore want
+to override the blacklisting can either load the blacklisted module
+directly:
+.RS
+
+.br
+.BI "modprobe -v" " somefs"
+.br
+
+.RE
+or override the blacklist configuration by editing files under the
+.I /etc/modprobe.d
+directory.
+
 .SS Bind mount operation
 Remount part of the file hierarchy somewhere else.  The call is:
 
-- 
2.19.2