[ Upstream commit 6af36aeb147a06dea47c49859cd6ca5659aeb987 ]

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>
[Mainline declares lsm_backing_file_cache in security/lsm.h.  Linux 6.18.y
does not have security/lsm_init.c or security/lsm.h; the cache variable
is defined locally as static struct kmem_cache *lsm_backing_file_cache in
security/security.c.]
Signed-off-by: Cai Xinchen <caixinchen1@huawei.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit 1613462be621ad5103ec338a7b0ca0746ec4e5f1 upstream.

When running in an unprivileged domU under Xen, the privcmd driver
is restricted to allow only hypercalls against a target domain, for
which the current domU is acting as a device model.

Add a boot parameter "unrestricted" to allow all hypercalls (the
hypervisor will still refuse destructive hypercalls affecting other
guests).

Make this new parameter effective only in case the domU wasn't started
using secure boot, as otherwise hypercalls targeting the domU itself
might result in violating the secure boot functionality.

This is achieved by adding another lockdown reason, which can be
tested to not being set when applying the "unrestricted" option.

This is part of XSA-482

Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull d_name audit update from Al Viro:
 "Simplifying ->d_name audits, easy part.

  Turn dentry->d_name into an anon union of const struct qsrt (d_name
  itself) and a writable alias (__d_name).

  With constification of some struct qstr * arguments of functions that
  get &dentry->d_name passed to them, that ends up with all
  modifications provably done only in fs/dcache.c (and a fairly small
  part of it).

  Any new places doing modifications will be easy to find - grep for
  __d_name will suffice"

* tag 'pull-qstr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  make it easier to catch those who try to modify ->d_name
  generic_ci_validate_strict_name(): constify name argument
  afs_dir_search: constify qstr argument
  afs_edit_dir_{add,remove}(): constify qstr argument
  exfat_find(): constify qstr argument
  security_dentry_init_security(): constify qstr argument

Pull lsm updates from Paul Moore:

 - Move the management of the LSM BPF security blobs into the framework

   In order to enable multiple LSMs we need to allocate and free the
   various security blobs in the LSM framework and not the individual
   LSMs as they would end up stepping all over each other.

 - Leverage the lsm_bdev_alloc() helper in lsm_bdev_alloc()

   Make better use of our existing helper functions to reduce some code
   duplication.

 - Update the Rust cred code to use 'sync::aref'

   Part of a larger effort to move the Rust code over to the 'sync'
   module.

 - Make CONFIG_LSM dependent on CONFIG_SECURITY

   As the CONFIG_LSM Kconfig setting is an ordered list of the LSMs to
   enable a boot, it obviously doesn't make much sense to enable this
   when CONFIG_SECURITY is disabled.

 - Update the LSM and CREDENTIALS sections in MAINTAINERS with Rusty
   bits

   Add the Rust helper files to the associated LSM and CREDENTIALS
   entries int the MAINTAINERS file. We're trying to improve the
   communication between the two groups and making sure we're all aware
   of what is going on via cross-posting to the relevant lists is a good
   way to start.

* tag 'lsm-pr-20250926' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: CONFIG_LSM can depend on CONFIG_SECURITY
  MAINTAINERS: add the associated Rust helper to the CREDENTIALS section
  MAINTAINERS: add the associated Rust helper to the LSM section
  rust,cred: update AlwaysRefCounted import to sync::aref
  security: use umax() to improve code
  lsm,selinux: Add LSM blob support for BPF objects
  lsm: use lsm_blob_alloc() in lsm_bdev_alloc()

Pull audit updates from Paul Moore:

 - Proper audit support for multiple LSMs

   As the audit subsystem predated the work to enable multiple LSMs,
   some additional work was needed to support logging the different LSM
   labels for the subjects/tasks and objects on the system. Casey's
   patches add new auxillary records for subjects and objects that
   convey the additional labels.

 - Ensure fanotify audit events are always generated

   Generally speaking security relevant subsystems always generate audit
   events, unless explicitly ignored. However, up to this point fanotify
   events had been ignored by default, but starting with this pull
   request fanotify follows convention and generates audit events by
   default.

 - Replace an instance of strcpy() with strscpy()

 - Minor indentation, style, and comment fixes

* tag 'audit-pr-20250926' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: fix skb leak when audit rate limit is exceeded
  audit: init ab->skb_list earlier in audit_buffer_alloc()
  audit: add record for multiple object contexts
  audit: add record for multiple task security contexts
  lsm: security_lsmblob_to_secctx module selection
  audit: create audit_stamp structure
  audit: add a missing tab
  audit: record fanotify event regardless of presence of rules
  audit: fix typo in auditfilter.c comment
  audit: Replace deprecated strcpy() with strscpy()
  audit: fix indentation in audit_log_exit()

Nothing outside of fs/dcache.c has any business modifying
dentry names; passing &dentry->d_name as an argument should
have that argument declared as a const pointer.

Acked-by: Casey Schaufler <casey@schaufler-ca.com> # smack part
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

With the introduction of clone3 in commit 7f192e3cd316 ("fork: add
clone3") the effective bit width of clone_flags on all architectures was
increased from 32-bit to 64-bit, with a new type of u64 for the flags.
However, for most consumers of clone_flags the interface was not
changed from the previous type of unsigned long.

While this works fine as long as none of the new 64-bit flag bits
(CLONE_CLEAR_SIGHAND and CLONE_INTO_CGROUP) are evaluated, this is still
undesirable in terms of the principle of least surprise.

Thus, this commit fixes all relevant interfaces of callees to
sys_clone3/copy_process (excluding the architecture-specific
copy_thread) to consistently pass clone_flags as u64, so that
no truncation to 32-bit integers occurs on 32-bit architectures.

Signed-off-by: Simon Schuster <schuster.simon@siemens-energy.com>
Link: https://lore.kernel.org/20250901-nios2-implement-clone3-v2-2-53fcf5577d57@siemens-energy.com
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Add a parameter lsmid to security_lsmblob_to_secctx() to identify which
of the security modules that may be active should provide the security
context. If the value of lsmid is LSM_ID_UNDEF the first LSM providing
a hook is used. security_secid_to_secctx() is unchanged, and will
always report the first LSM providing a hook.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subj tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

This patch introduces LSM blob support for BPF maps, programs, and
tokens to enable LSM stacking and multiplexing of LSM modules that
govern BPF objects. Additionally, the existing BPF hooks used by
SELinux have been updated to utilize the new blob infrastructure,
removing the assumption of exclusive ownership of the security
pointer.

Signed-off-by: Blaise Boscaccy <bboscaccy@linux.microsoft.com>
[PM: dropped local variable init, style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>

Convert the lsm_bdev_alloc() function to use the lsm_blob_alloc() helper
like all of the other LSM security blob allocators.

Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>