Re: HFS/HFS+ are insecure

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From	Matthew Garrett <mjg59@srcf.ucam.org>
Newsgroups	linux.debian.devel, linux.debian.kernel, linux.debian.bugs.dist
Subject	Re: HFS/HFS+ are insecure
Date	Fri, 21 Jul 2023 19:40:04 +0200
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Cross-posted to 3 groups.

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On Fri, Jul 21, 2023 at 10:55:39AM +0200, Marco d'Itri wrote:

> Unless somebody has a better idea then then my plan is to ship in the 
> next upload of kmod a file in /etc/modprobe.d/ which uses the blacklist 
> directive to prevent automatically loading some file system modules.

I think this would break any existing fstab entries that reference hfs 
and hfsplus, and the convenient way to integrate Linux boot with x86 
Macs is certainly to have an hfsplus EFI partition so this may be a 
legitimate use-case. It also means that anyone who has a need to use one 
of these filesystems in a static manner is vulnerable to automount 
attacks using them.

Completely untested, but I think something along the lines of:

SUBSYSTEM!="block", GOTO="udisks_insecure_fs_end"
ENV{ID_FS_TYPE}=="hfs", ENV{UDISKS_AUTO}="0"
ENV{ID_FS_TYPE}=="hfsplus", ENV{UDISKS_AUTO}="0"
LABEL="udisks_insecure_fs_end"

in a udev fragment should work? Any static fstab or mount units should 
still work, but it should disable udisks automounting regardless of the 
desktop agent involved, even if the fs modules are already loaded.

Thread

Bug#1041552: HFS/HFS+ are insecure Marco d'Itri <md@Linux.IT> - 2023-07-20 20:10 +0200
  Re: HFS/HFS+ are insecure Marco d'Itri <md@Linux.IT> - 2023-07-21 11:00 +0200
    Re: HFS/HFS+ are insecure Magissia <debianlist@magissia.com> - 2023-07-21 11:10 +0200
    Re: HFS/HFS+ are insecure Martin Steigerwald <martin@lichtvoll.de> - 2023-07-21 12:10 +0200
    Re: HFS/HFS+ are insecure Bastien Roucariès <rouca@debian.org> - 2023-07-21 13:00 +0200
      Re: HFS/HFS+ are insecure Bastien Roucariès <rouca@debian.org> - 2023-07-21 13:10 +0200
    Re: HFS/HFS+ are insecure Matthew Garrett <mjg59@srcf.ucam.org> - 2023-07-21 19:40 +0200
      Re: HFS/HFS+ are insecure Ben Hutchings <ben@decadent.org.uk> - 2023-07-23 02:40 +0200
  Processed: Re: HFS/HFS+ are insecure "Debian Bug Tracking System" <owner@bugs.debian.org> - 2023-08-27 02:40 +0200
  Bug#1041552: HFS/HFS+ are insecure Marco d'Itri <md@Linux.IT> - 2023-08-27 02:40 +0200

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