linux/include
Topi Miettinen 901cff7cb9 firmware_loader: load files from the mount namespace of init
I have an experimental setup where almost every possible system
service (even early startup ones) runs in separate namespace, using a
dedicated, minimal file system. In process of minimizing the contents
of the file systems with regards to modules and firmware files, I
noticed that in my system, the firmware files are loaded from three
different mount namespaces, those of systemd-udevd, init and
systemd-networkd. The logic of the source namespace is not very clear,
it seems to depend on the driver, but the namespace of the current
process is used.

So, this patch tries to make things a bit clearer and changes the
loading of firmware files only from the mount namespace of init. This
may also improve security, though I think that using firmware files as
attack vector could be too impractical anyway.

Later, it might make sense to make the mount namespace configurable,
for example with a new file in /proc/sys/kernel/firmware_config/. That
would allow a dedicated file system only for firmware files and those
need not be present anywhere else. This configurability would make
more sense if made also for kernel modules and /sbin/modprobe. Modules
are already loaded from init namespace (usermodehelper uses kthreadd
namespace) except when directly loaded by systemd-udevd.

Instead of using the mount namespace of the current process to load
firmware files, use the mount namespace of init process.

Link: https://lore.kernel.org/lkml/bb46ebae-4746-90d9-ec5b-fce4c9328c86@gmail.com/
Link: https://lore.kernel.org/lkml/0e3f7653-c59d-9341-9db2-c88f5b988c68@gmail.com/
Signed-off-by: Topi Miettinen <toiwoton@gmail.com>
Link: https://lore.kernel.org/r/20200123125839.37168-1-toiwoton@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-10 15:39:28 -08:00
..
acpi
asm-generic Microblaze patches for 5.6-rc1 2020-02-04 11:58:07 +00:00
clocksource clocksource/drivers/hyper-v: Untangle stimers and timesync from clocksources 2020-01-16 19:09:02 +01:00
crypto crypto: poly1305 - add new 32 and 64-bit generic versions 2020-01-16 15:18:12 +08:00
drm drm/amdgpu: fix doc by clarifying sched_list definition 2020-01-27 16:46:44 -05:00
dt-bindings ARM: SoC: late updates 2020-02-08 14:17:27 -08:00
keys
kunit
kvm
linux firmware_loader: load files from the mount namespace of init 2020-02-10 15:39:28 -08:00
math-emu
media
misc
net bonding/alb: properly access headers in bond_alb_xmit() 2020-02-05 14:28:09 +01:00
pcmcia
ras
rdma RDMA/core: Make the entire API tree static 2020-01-30 16:28:52 -04:00
scsi
soc ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
sound ARM: Device-tree updates 2020-02-08 13:58:44 -08:00
target
trace ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
uapi fs: New zonefs file system 2020-02-09 15:51:46 -08:00
vdso lib/vdso: Prepare for time namespace support 2020-01-14 12:20:57 +01:00
video
xen xen: branch for v5.6-rc1 2020-02-05 17:44:14 +00:00