linux/include
Paul Moore 6af36aeb14 lsm: add backing_file LSM hooks
Stacked filesystems such as overlayfs do not currently provide the
necessary mechanisms for LSMs to properly enforce access controls on the
mmap() and mprotect() operations.  In order to resolve this gap, a LSM
security blob is being added to the backing_file struct and the following
new LSM hooks are being created:

 security_backing_file_alloc()
 security_backing_file_free()
 security_mmap_backing_file()

The first two hooks are to manage the lifecycle of the LSM security blob
in the backing_file struct, while the third provides a new mmap() access
control point for the underlying backing file.  It is also expected that
LSMs will likely want to update their security_file_mprotect() callback
to address issues with their mprotect() controls, but that does not
require a change to the security_file_mprotect() LSM hook.

There are a three other small changes to support these new LSM hooks:
* Pass the user file associated with a backing file down to
alloc_empty_backing_file() so it can be included in the
security_backing_file_alloc() hook.
* Add getter and setter functions for the backing_file struct LSM blob
as the backing_file struct remains private to fs/file_table.c.
* Constify the file struct field in the LSM common_audit_data struct to
better support LSMs that need to pass a const file struct pointer into
the common LSM audit code.

Thanks to Arnd Bergmann for identifying the missing EXPORT_SYMBOL_GPL()
and supplying a fixup.

Cc: stable@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-unionfs@vger.kernel.org
Cc: linux-erofs@lists.ozlabs.org
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2026-04-03 16:53:50 -04:00
..
acpi mailbox: platform and core updates 2026-02-14 11:13:32 -08:00
asm-generic hyperv-next for v7.0 2026-02-20 08:48:31 -08:00
clocksource
crypto Networking changes for 7.0 2026-02-11 19:31:52 -08:00
cxl
drm drm/pagemap: pass pagemap_addr by reference 2026-02-17 19:39:44 -05:00
dt-bindings phy-for-7.0 2026-02-17 11:40:04 -08:00
hyperv hyperv-next for v7.0 2026-02-20 08:48:31 -08:00
keys
kunit treewide: Replace kmalloc with kmalloc_obj for non-scalar types 2026-02-21 01:02:28 -08:00
kvm KVM: arm64: Use standard seq_file iterator for vgic-debug debugfs 2026-02-02 10:59:25 +00:00
linux lsm: add backing_file LSM hooks 2026-04-03 16:53:50 -04:00
math-emu
media [GIT PULL for v7.0] media updates 2026-02-11 12:20:25 -08:00
memory
misc
net Convert more 'alloc_obj' cases to default GFP_KERNEL arguments 2026-02-21 20:03:00 -08:00
pcmcia
ras
rdma RDMA v7.0 merge window 2026-02-12 17:05:20 -08:00
rv rv: Fix multiple definition of __pcpu_unique_da_mon_this 2026-02-20 13:12:00 +01:00
scsi SCSI misc on 20260212 2026-02-12 15:43:02 -08:00
soc
sound ASoC: Updates for v7.0 2026-02-09 17:39:11 +01:00
target
trace vfs-7.0-rc1.misc.2 2026-02-16 13:00:36 -08:00
uapi drm next fixes for 7.0-rc1 2026-02-20 15:36:38 -08:00
ufs scsi: ufs: host: mediatek: Require CONFIG_PM 2026-02-03 22:28:44 -05:00
vdso
video
xen Partial revert "x86/xen: fix balloon target initialization for PVH dom0" 2026-02-02 07:31:22 +01:00
Kbuild