Pull persistent dentry infrastructure and conversion from Al Viro:
"Some filesystems use a kinda-sorta controlled dentry refcount leak to
pin dentries of created objects in dcache (and undo it when removing
those). A reference is grabbed and not released, but it's not actually
_stored_ anywhere.
That works, but it's hard to follow and verify; among other things, we
have no way to tell _which_ of the increments is intended to be an
unpaired one. Worse, on removal we need to decide whether the
reference had already been dropped, which can be non-trivial if that
removal is on umount and we need to figure out if this dentry is
pinned due to e.g. unlink() not done. Usually that is handled by using
kill_litter_super() as ->kill_sb(), but there are open-coded special
cases of the same (consider e.g. /proc/self).
Things get simpler if we introduce a new dentry flag
(DCACHE_PERSISTENT) marking those "leaked" dentries. Having it set
claims responsibility for +1 in refcount.
The end result this series is aiming for:
- get these unbalanced dget() and dput() replaced with new primitives
that would, in addition to adjusting refcount, set and clear
persistency flag.
- instead of having kill_litter_super() mess with removing the
remaining "leaked" references (e.g. for all tmpfs files that hadn't
been removed prior to umount), have the regular
shrink_dcache_for_umount() strip DCACHE_PERSISTENT of all dentries,
dropping the corresponding reference if it had been set. After that
kill_litter_super() becomes an equivalent of kill_anon_super().
Doing that in a single step is not feasible - it would affect too many
places in too many filesystems. It has to be split into a series.
This work has really started early in 2024; quite a few preliminary
pieces have already gone into mainline. This chunk is finally getting
to the meat of that stuff - infrastructure and most of the conversions
to it.
Some pieces are still sitting in the local branches, but the bulk of
that stuff is here"
* tag 'pull-persistency' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (54 commits)
d_make_discardable(): warn if given a non-persistent dentry
kill securityfs_recursive_remove()
convert securityfs
get rid of kill_litter_super()
convert rust_binderfs
convert nfsctl
convert rpc_pipefs
convert hypfs
hypfs: swich hypfs_create_u64() to returning int
hypfs: switch hypfs_create_str() to returning int
hypfs: don't pin dentries twice
convert gadgetfs
gadgetfs: switch to simple_remove_by_name()
convert functionfs
functionfs: switch to simple_remove_by_name()
functionfs: fix the open/removal races
functionfs: need to cancel ->reset_work in ->kill_sb()
functionfs: don't bother with ffs->ref in ffs_data_{opened,closed}()
functionfs: don't abuse ffs_data_closed() on fs shutdown
convert selinuxfs
...
Move the LSM active count and lsm_id list declarations out of a header
that is visible across the kernel and into a header that is limited to
the LSM framework. This not only helps keep the include/linux headers
smaller and cleaner, it helps prevent misuse of these variables.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johhansen@canonical.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
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 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 7f192e3cd3 ("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>
Pull lsm updates from Paul Moore:
- Add Nicolas Bouchinet and Xiu Jianfeng as Lockdown maintainers
The Lockdown LSM has been without a dedicated mantainer since its
original acceptance upstream, and it has suffered as a result.
Thankfully we have two new volunteers who together I believe have the
background and desire to help ensure Lockdown is properly supported.
- Remove the unused cap_mmap_file() declaration
* tag 'lsm-pr-20250725' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
MAINTAINERS: Add Xiu and myself as Lockdown maintainers
security: Remove unused declaration cap_mmap_file()
lsm: trivial comment fix
Pull fileattr updates from Christian Brauner:
"This introduces the new file_getattr() and file_setattr() system calls
after lengthy discussions.
Both system calls serve as successors and extensible companions to
the FS_IOC_FSGETXATTR and FS_IOC_FSSETXATTR system calls which have
started to show their age in addition to being named in a way that
makes it easy to conflate them with extended attribute related
operations.
These syscalls allow userspace to set filesystem inode attributes on
special files. One of the usage examples is the XFS quota projects.
XFS has project quotas which could be attached to a directory. All new
inodes in these directories inherit project ID set on parent
directory.
The project is created from userspace by opening and calling
FS_IOC_FSSETXATTR on each inode. This is not possible for special
files such as FIFO, SOCK, BLK etc. Therefore, some inodes are left
with empty project ID. Those inodes then are not shown in the quota
accounting but still exist in the directory. This is not critical but
in the case when special files are created in the directory with
already existing project quota, these new inodes inherit extended
attributes. This creates a mix of special files with and without
attributes. Moreover, special files with attributes don't have a
possibility to become clear or change the attributes. This, in turn,
prevents userspace from re-creating quota project on these existing
files.
In addition, these new system calls allow the implementation of
additional attributes that we couldn't or didn't want to fit into the
legacy ioctls anymore"
* tag 'vfs-6.17-rc1.fileattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: tighten a sanity check in file_attr_to_fileattr()
tree-wide: s/struct fileattr/struct file_kattr/g
fs: introduce file_getattr and file_setattr syscalls
fs: prepare for extending file_get/setattr()
fs: make vfs_fileattr_[get|set] return -EOPNOTSUPP
selinux: implement inode_file_[g|s]etattr hooks
lsm: introduce new hooks for setting/getting inode fsxattr
fs: split fileattr related helpers into separate file
... and fix the mount leak when anything's mounted there.
securityfs_recursive_remove becomes an alias for securityfs_remove -
we'll probably need to remove it in a cycle or two.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
security_netlink_send() is a networking hook, so it fits better under
CONFIG_SECURITY_NETWORK.
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull bpf updates from Alexei Starovoitov:
"For this merge window we're splitting BPF pull request into three for
higher visibility: main changes, res_spin_lock, try_alloc_pages.
These are the main BPF changes:
- Add DFA-based live registers analysis to improve verification of
programs with loops (Eduard Zingerman)
- Introduce load_acquire and store_release BPF instructions and add
x86, arm64 JIT support (Peilin Ye)
- Fix loop detection logic in the verifier (Eduard Zingerman)
- Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet)
- Add kfunc for populating cpumask bits (Emil Tsalapatis)
- Convert various shell based tests to selftests/bpf/test_progs
format (Bastien Curutchet)
- Allow passing referenced kptrs into struct_ops callbacks (Amery
Hung)
- Add a flag to LSM bpf hook to facilitate bpf program signing
(Blaise Boscaccy)
- Track arena arguments in kfuncs (Ihor Solodrai)
- Add copy_remote_vm_str() helper for reading strings from remote VM
and bpf_copy_from_user_task_str() kfunc (Jordan Rome)
- Add support for timed may_goto instruction (Kumar Kartikeya
Dwivedi)
- Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy)
- Reduce bpf_cgrp_storage_busy false positives when accessing cgroup
local storage (Martin KaFai Lau)
- Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko)
- Allow retrieving BTF data with BTF token (Mykyta Yatsenko)
- Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix
(Song Liu)
- Reject attaching programs to noreturn functions (Yafang Shao)
- Introduce pre-order traversal of cgroup bpf programs (Yonghong
Song)"
* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits)
selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid
bpf: Fix out-of-bounds read in check_atomic_load/store()
libbpf: Add namespace for errstr making it libbpf_errstr
bpf: Add struct_ops context information to struct bpf_prog_aux
selftests/bpf: Sanitize pointer prior fclose()
selftests/bpf: Migrate test_xdp_vlan.sh into test_progs
selftests/bpf: test_xdp_vlan: Rename BPF sections
bpf: clarify a misleading verifier error message
selftests/bpf: Add selftest for attaching fexit to __noreturn functions
bpf: Reject attaching fexit/fmod_ret to __noreturn functions
bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
bpf: Make perf_event_read_output accessible in all program types.
bpftool: Using the right format specifiers
bpftool: Add -Wformat-signedness flag to detect format errors
selftests/bpf: Test freplace from user namespace
libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID
bpf: Return prog btf_id without capable check
bpf: BPF token support for BPF_BTF_GET_FD_BY_ID
bpf, x86: Fix objtool warning for timed may_goto
bpf: Check map->record at the beginning of check_and_free_fields()
...
Certain bpf syscall subcommands are available for usage from both
userspace and the kernel. LSM modules or eBPF gatekeeper programs may
need to take a different course of action depending on whether or not
a BPF syscall originated from the kernel or userspace.
Additionally, some of the bpf_attr struct fields contain pointers to
arbitrary memory. Currently the functionality to determine whether or
not a pointer refers to kernel memory or userspace memory is exposed
to the bpf verifier, but that information is missing from various LSM
hooks.
Here we augment the LSM hooks to provide this data, by simply passing
a boolean flag indicating whether or not the call originated in the
kernel, in any hook that contains a bpf_attr struct that corresponds
to a subcommand that may be called from the kernel.
Signed-off-by: Blaise Boscaccy <bboscaccy@linux.microsoft.com>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20250310221737.821889-2-bboscaccy@linux.microsoft.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
It seems that the attr parameter was never been used in security
checks since it was first introduced by:
commit da97e18458 ("perf_event: Add support for LSM and SELinux checks")
so remove it.
Signed-off-by: Luo Gengkun <luogengkun@huaweicloud.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The !CONFIG_SECURITY dummy function was declared as an "extern int"
instead of "static inline" (likely a copy-n-paste error), which was
was causing the compiler to complain about a missing prototype. This
patch converts the dummy definition over to a "static inline" to resolve
the compiler problems.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/oe-kbuild-all/202502081912.TeokpAAe-lkp@intel.com/
Fixes: c6ad9fdbd4 ("io_uring,lsm,selinux: add LSM hooks for io_uring_setup()")
Signed-off-by: Paul Moore <paul@paul-moore.com>
It is desirable to allow LSM to configure accessibility to io_uring
because it is a coarse yet very simple way to restrict access to it. So,
add an LSM for io_uring_allowed() to guard access to io_uring.
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
[PM: merge fuzz due to changes in preceding patches, subj tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Replace the (secctx,seclen) pointer pair with a single lsm_context
pointer to allow return of the LSM identifier along with the context
and context length. This allows security_release_secctx() to know how
to release the context. Callers have been modified to use or save the
returned data from the new structure.
Cc: ceph-devel@vger.kernel.org
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Change the security_inode_getsecctx() interface to fill a lsm_context
structure instead of data and length pointers. This provides
the information about which LSM created the context so that
security_release_secctx() can use the correct hook.
Cc: linux-nfs@vger.kernel.org
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Replace the (secctx,seclen) pointer pair with a single
lsm_context pointer to allow return of the LSM identifier
along with the context and context length. This allows
security_release_secctx() to know how to release the
context. Callers have been modified to use or save the
returned data from the new structure.
security_secid_to_secctx() and security_lsmproc_to_secctx()
will now return the length value on success instead of 0.
Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak, kdoc fix, signedness fix from Dan Carpenter]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Add a new lsm_context data structure to hold all the information about a
"security context", including the string, its size and which LSM allocated
the string. The allocation information is necessary because LSMs have
different policies regarding the lifecycle of these strings. SELinux
allocates and destroys them on each use, whereas Smack provides a pointer
to an entry in a list that never goes away.
Update security_release_secctx() to use the lsm_context instead of a
(char *, len) pair. Change its callers to do likewise. The LSMs
supporting this hook have had comments added to remind the developer
that there is more work to be done.
The BPF security module provides all LSM hooks. While there has yet to
be a known instance of a BPF configuration that uses security contexts,
the possibility is real. In the existing implementation there is
potential for multiple frees in that case.
Cc: linux-integrity@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: audit@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: linux-nfs@vger.kernel.org
Cc: Todd Kjos <tkjos@google.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Linus Torvalds
Al Viro
Paul Moore
Simon Schuster
Casey Schaufler
Christian Brauner
Andrey Albershteyn
Yue Haibing
Song Liu
Blaise Boscaccy
Luo Gengkun
Hamza Mahfooz