Commit Graph

1861 Commits

Author SHA1 Message Date
David Howells 71512d0d79 vfs, security: Fix automount superblock LSM init problem, preventing NFS sb sharing
[ Upstream commit d80a8f1b58 ]

When NFS superblocks are created by automounting, their LSM parameters
aren't set in the fs_context struct prior to sget_fc() being called,
leading to failure to match existing superblocks.

This bug leads to messages like the following appearing in dmesg when
fscache is enabled:

    NFS: Cache volume key already in use (nfs,4.2,2,108,106a8c0,1,,,,100000,100000,2ee,3a98,1d4c,3a98,1)

Fix this by adding a new LSM hook to load fc->security for submount
creation.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/165962680944.3334508.6610023900349142034.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165962729225.3357250.14350728846471527137.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/165970659095.2812394.6868894171102318796.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/166133579016.3678898.6283195019480567275.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/217595.1662033775@warthog.procyon.org.uk/ # v5
Fixes: 9bc61ab18b ("vfs: Introduce fs_context, switch vfs_kern_mount() to it.")
Fixes: 779df6a548 ("NFS: Ensure security label is set for root inode")
Tested-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: "Christian Brauner (Microsoft)" <brauner@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230808-master-v9-1-e0ecde888221@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-13 09:47:57 +02:00
Christian Göttsche 21cd99431a selinux: set next pointer before attaching to list
commit 70d91dc9b2 upstream.

Set the next pointer in filename_trans_read_helper() before attaching
the new node under construction to the list, otherwise garbage would be
dereferenced on subsequent failure during cleanup in the out goto label.

Cc: <stable@vger.kernel.org>
Fixes: 4300590243 ("selinux: implement new format of filename transitions")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-08-30 14:52:40 +02:00
Paul Moore 42c4e97e06 selinux: don't use make's grouped targets feature yet
The Linux Kernel currently only requires make v3.82 while the grouped
target functionality requires make v4.3.  Removed the grouped target
introduced in 4ce1f694eb ("selinux: ensure av_permissions.h is
built when needed") as well as the multiple header file targets in
the make rule.  This effectively reverts the problem commit.

We will revisit this change when make >= 4.3 is required by the rest
of the kernel.

Cc: stable@vger.kernel.org
Fixes: 4ce1f694eb ("selinux: ensure av_permissions.h is built when needed")
Reported-by: Erwan Velu <e.velu@criteo.com>
Reported-by: Luiz Capitulino <luizcap@amazon.com>
Tested-by: Luiz Capitulino <luizcap@amazon.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-06-01 13:56:13 -04:00
Paul Moore 4ce1f694eb selinux: ensure av_permissions.h is built when needed
The Makefile rule responsible for building flask.h and
av_permissions.h only lists flask.h as a target which means that
av_permissions.h is only generated when flask.h needs to be
generated.  This patch fixes this by adding av_permissions.h as a
target to the rule.

Fixes: 8753f6bec3 ("selinux: generate flask headers during kernel build")
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-04-12 19:46:35 -04:00
Ondrej Mosnacek bcab1adeaa selinux: fix Makefile dependencies of flask.h
Make the flask.h target depend on the genheaders binary instead of
classmap.h to ensure that it is rebuilt if any of the dependencies of
genheaders are changed.

Notably this fixes flask.h not being rebuilt when
initial_sid_to_string.h is modified.

Fixes: 8753f6bec3 ("selinux: generate flask headers during kernel build")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-04-12 13:34:20 -04:00
Stephen Smalley 539813e418 selinux: stop returning node from avc_insert()
The callers haven't used the returned node since
commit 21193dcd1f ("SELinux: more careful use of avd in
avc_has_perm_noaudit") and the return value assignments were removed in
commit 0a9876f36b ("selinux: Remove redundant assignments"). Stop
returning the node altogether and make the functions return void.

Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
PM: minor subj tweak, repair whitespace damage
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-04-04 12:05:42 -04:00
Paul Moore f22f9aaf6c selinux: remove the runtime disable functionality
After working with the larger SELinux-based distros for several
years, we're finally at a place where we can disable the SELinux
runtime disable functionality.  The existing kernel deprecation
notice explains the functionality and why we want to remove it:

  The selinuxfs "disable" node allows SELinux to be disabled at
  runtime prior to a policy being loaded into the kernel.  If
  disabled via this mechanism, SELinux will remain disabled until
  the system is rebooted.

  The preferred method of disabling SELinux is via the "selinux=0"
  boot parameter, but the selinuxfs "disable" node was created to
  make it easier for systems with primitive bootloaders that did not
  allow for easy modification of the kernel command line.
  Unfortunately, allowing for SELinux to be disabled at runtime makes
  it difficult to secure the kernel's LSM hooks using the
  "__ro_after_init" feature.

It is that last sentence, mentioning the '__ro_after_init' hardening,
which is the real motivation for this change, and if you look at the
diffstat you'll see that the impact of this patch reaches across all
the different LSMs, helping prevent tampering at the LSM hook level.

From a SELinux perspective, it is important to note that if you
continue to disable SELinux via "/etc/selinux/config" it may appear
that SELinux is disabled, but it is simply in an uninitialized state.
If you load a policy with `load_policy -i`, you will see SELinux
come alive just as if you had loaded the policy during early-boot.

It is also worth noting that the "/sys/fs/selinux/disable" file is
always writable now, regardless of the Kconfig settings, but writing
to the file has no effect on the system, other than to display an
error on the console if a non-zero/true value is written.

Finally, in the several years where we have been working on
deprecating this functionality, there has only been one instance of
someone mentioning any user visible breakage.  In this particular
case it was an individual's kernel test system, and the workaround
documented in the deprecation notice ("selinux=0" on the kernel
command line) resolved the issue without problem.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-20 12:34:23 -04:00
Paul Moore a7e4676e8e selinux: remove the 'checkreqprot' functionality
We originally promised that the SELinux 'checkreqprot' functionality
would be removed no sooner than June 2021, and now that it is March
2023 it seems like it is a good time to do the final removal.  The
deprecation notice in the kernel provides plenty of detail on why
'checkreqprot' is not desirable, with the key point repeated below:

  This was a compatibility mechanism for legacy userspace and
  for the READ_IMPLIES_EXEC personality flag.  However, if set to
  1, it weakens security by allowing mappings to be made executable
  without authorization by policy.  The default value of checkreqprot
  at boot was changed starting in Linux v4.4 to 0 (i.e. check the
  actual protection), and Android and Linux distributions have been
  explicitly writing a "0" to /sys/fs/selinux/checkreqprot during
  initialization for some time.

Along with the official deprecation notice, we have been discussing
this on-list and directly with several of the larger SELinux-based
distros and everyone is happy to see this feature finally removed.
In an attempt to catch all of the smaller, and DIY, Linux systems
we have been writing a deprecation notice URL into the kernel log,
along with a growing ssleep() penalty, when admins enabled
checkreqprot at runtime or via the kernel command line.  We have
yet to have anyone come to us and raise an objection to the
deprecation or planned removal.

It is worth noting that while this patch removes the checkreqprot
functionality, it leaves the user visible interfaces (kernel command
line and selinuxfs file) intact, just inert.  This should help
prevent breakages with existing userspace tools that correctly, but
unnecessarily, disable checkreqprot at boot or runtime.  Admins
that attempt to enable checkreqprot will be met with a removal
message in the kernel log.

Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-20 12:33:50 -04:00
Stephen Smalley e67b79850f selinux: stop passing selinux_state pointers and their offspring
Linus observed that the pervasive passing of selinux_state pointers
introduced by me in commit aa8e712cee ("selinux: wrap global selinux
state") adds overhead and complexity without providing any
benefit. The original idea was to pave the way for SELinux namespaces
but those have not yet been implemented and there isn't currently
a concrete plan to do so. Remove the passing of the selinux_state
pointers, reverting to direct use of the single global selinux_state,
and likewise remove passing of child pointers like the selinux_avc.
The selinux_policy pointer remains as it is needed for atomic switching
of policies.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/oe-kbuild-all/202303101057.mZ3Gv5fK-lkp@intel.com/
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-14 15:22:45 -04:00
Paul Moore f62ca0b6e3 selinux: uninline unlikely parts of avc_has_perm_noaudit()
This is based on earlier patch posted to the list by Linus, his
commit description read:

 "avc_has_perm_noaudit()is one of those hot functions that end up
  being used by almost all filesystem operations (through
  "avc_has_perm()") and it's intended to be cheap enough to inline.

  However, it turns out that the unlikely parts of it (where it
  doesn't find an existing avc node) need a fair amount of stack
  space for the automatic replacement node, so if it were to be
  inlined (at least clang does not) it would just use stack space
  unnecessarily.

  So split the unlikely part out of it, and mark that part noinline.
  That improves the actual likely part."

The basic idea behind the patch was reasonable, but there were minor
nits (double indenting, etc.) and the RCU read lock unlock/re-lock in
avc_compute_av() began to look even more ugly.  This patch builds on
Linus' first effort by cleaning things up a bit and removing the RCU
unlock/lock dance in avc_compute_av().

Removing the RCU lock dance in avc_compute_av() is safe as there are
currently two callers of avc_compute_av(): avc_has_perm_noaudit() and
avc_has_extended_perms().  The first caller in avc_has_perm_noaudit()
does not require a RCU lock as there is no avc_node to protect so the
RCU lock can be dropped before calling avc_compute_av().  The second
caller, avc_has_extended_perms(), is similar in that there is no
avc_node that requires RCU protection, but the code is simplified by
holding the RCU look around the avc_compute_av() call, and given that
we enter a RCU critical section in security_compute_av() (called from
av_compute_av()) the impact will likely be unnoticeable.  It is also
worth noting that avc_has_extended_perms() is only called from the
SELinux ioctl() access control hook at the moment.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2023-03-08 11:48:27 -05:00
Linus Torvalds 3822a7c409 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X bit.
 
 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.
 
 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes
 
 - Johannes Weiner has a series ("mm: push down lock_page_memcg()") which
   does perform some memcg maintenance and cleanup work.
 
 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".  These filters provide users
   with finer-grained control over DAMOS's actions.  SeongJae has also done
   some DAMON cleanup work.
 
 - Kairui Song adds a series ("Clean up and fixes for swap").
 
 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".
 
 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series.  It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.
 
 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".
 
 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".
 
 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".
 
 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".
 
 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series "mm:
   support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with swap
   PTEs".
 
 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".
 
 - Sergey Senozhatsky has improved zsmalloc's memory utilization with his
   series "zsmalloc: make zspage chain size configurable".
 
 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.  The previous BPF-based approach had
   shortcomings.  See "mm: In-kernel support for memory-deny-write-execute
   (MDWE)".
 
 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
 
 - T.J.  Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".
 
 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a per-node
   basis.  See the series "Introduce per NUMA node memory error
   statistics".
 
 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage during
   compaction".
 
 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".
 
 - Christoph Hellwig has removed block_device_operations.rw_page() in ths
   series "remove ->rw_page".
 
 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".
 
 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier functions".
 
 - Some pagemap cleanup and generalization work in Mike Rapoport's series
   "mm, arch: add generic implementation of pfn_valid() for FLATMEM" and
   "fixups for generic implementation of pfn_valid()"
 
 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
 
 - Jason Gunthorpe rationalized the GUP system's interface to the rest of
   the kernel in the series "Simplify the external interface for GUP".
 
 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface.  To support this, we'll temporarily be
   printing warnings when people use the debugfs interface.  See the series
   "mm/damon: deprecate DAMON debugfs interface".
 
 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.
 
 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".
 
 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".
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Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...
2023-02-23 17:09:35 -08:00
Suren Baghdasaryan 1c71222e5f mm: replace vma->vm_flags direct modifications with modifier calls
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.

[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-02-09 16:51:39 -08:00
Christian Brauner 01beba7957
fs: port inode_owner_or_capable() to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:29 +01:00
Christian Brauner 700b794052
fs: port acl to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00
Christian Brauner 39f60c1cce
fs: port xattr to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00
Christian Brauner 4609e1f18e
fs: port ->permission() to pass mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00
Linus Torvalds c76ff350bd lsm/stable-6.2 PR 20221212
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Merge tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull lsm updates from Paul Moore:

 - Improve the error handling in the device cgroup such that memory
   allocation failures when updating the access policy do not
   potentially alter the policy.

 - Some minor fixes to reiserfs to ensure that it properly releases
   LSM-related xattr values.

 - Update the security_socket_getpeersec_stream() LSM hook to take
   sockptr_t values.

   Previously the net/BPF folks updated the getsockopt code in the
   network stack to leverage the sockptr_t type to make it easier to
   pass both kernel and __user pointers, but unfortunately when they did
   so they didn't convert the LSM hook.

   While there was/is no immediate risk by not converting the LSM hook,
   it seems like this is a mistake waiting to happen so this patch
   proactively does the LSM hook conversion.

 - Convert vfs_getxattr_alloc() to return an int instead of a ssize_t
   and cleanup the callers. Internally the function was never going to
   return anything larger than an int and the callers were doing some
   very odd things casting the return value; this patch fixes all that
   and helps bring a bit of sanity to vfs_getxattr_alloc() and its
   callers.

 - More verbose, and helpful, LSM debug output when the system is booted
   with "lsm.debug" on the command line. There are examples in the
   commit description, but the quick summary is that this patch provides
   better information about which LSMs are enabled and the ordering in
   which they are processed.

 - General comment and kernel-doc fixes and cleanups.

* tag 'lsm-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lsm: Fix description of fs_context_parse_param
  lsm: Add/fix return values in lsm_hooks.h and fix formatting
  lsm: Clarify documentation of vm_enough_memory hook
  reiserfs: Add missing calls to reiserfs_security_free()
  lsm,fs: fix vfs_getxattr_alloc() return type and caller error paths
  device_cgroup: Roll back to original exceptions after copy failure
  LSM: Better reporting of actual LSMs at boot
  lsm: make security_socket_getpeersec_stream() sockptr_t safe
  audit: Fix some kernel-doc warnings
  lsm: remove obsoleted comments for security hooks
  fs: edit a comment made in bad taste
2022-12-13 09:47:48 -08:00
Linus Torvalds 57888f7b95 selinux/stable-6.2 PR 20221212
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Merge tag 'selinux-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "Two SELinux patches: one increases the sleep time on deprecated
  functionality, and one removes the indirect calls in the sidtab
  context conversion code"

* tag 'selinux-pr-20221212' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: remove the sidtab context conversion indirect calls
  selinux: increase the deprecation sleep for checkreqprot and runtime disable
2022-12-13 09:32:05 -08:00
Linus Torvalds 6a518afcc2 fs.acl.rework.v6.2
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Merge tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull VFS acl updates from Christian Brauner:
 "This contains the work that builds a dedicated vfs posix acl api.

  The origins of this work trace back to v5.19 but it took quite a while
  to understand the various filesystem specific implementations in
  sufficient detail and also come up with an acceptable solution.

  As we discussed and seen multiple times the current state of how posix
  acls are handled isn't nice and comes with a lot of problems: The
  current way of handling posix acls via the generic xattr api is error
  prone, hard to maintain, and type unsafe for the vfs until we call
  into the filesystem's dedicated get and set inode operations.

  It is already the case that posix acls are special-cased to death all
  the way through the vfs. There are an uncounted number of hacks that
  operate on the uapi posix acl struct instead of the dedicated vfs
  struct posix_acl. And the vfs must be involved in order to interpret
  and fixup posix acls before storing them to the backing store, caching
  them, reporting them to userspace, or for permission checking.

  Currently a range of hacks and duct tape exist to make this work. As
  with most things this is really no ones fault it's just something that
  happened over time. But the code is hard to understand and difficult
  to maintain and one is constantly at risk of introducing bugs and
  regressions when having to touch it.

  Instead of continuing to hack posix acls through the xattr handlers
  this series builds a dedicated posix acl api solely around the get and
  set inode operations.

  Going forward, the vfs_get_acl(), vfs_remove_acl(), and vfs_set_acl()
  helpers must be used in order to interact with posix acls. They
  operate directly on the vfs internal struct posix_acl instead of
  abusing the uapi posix acl struct as we currently do. In the end this
  removes all of the hackiness, makes the codepaths easier to maintain,
  and gets us type safety.

  This series passes the LTP and xfstests suites without any
  regressions. For xfstests the following combinations were tested:
   - xfs
   - ext4
   - btrfs
   - overlayfs
   - overlayfs on top of idmapped mounts
   - orangefs
   - (limited) cifs

  There's more simplifications for posix acls that we can make in the
  future if the basic api has made it.

  A few implementation details:

   - The series makes sure to retain exactly the same security and
     integrity module permission checks. Especially for the integrity
     modules this api is a win because right now they convert the uapi
     posix acl struct passed to them via a void pointer into the vfs
     struct posix_acl format to perform permission checking on the mode.

     There's a new dedicated security hook for setting posix acls which
     passes the vfs struct posix_acl not a void pointer. Basing checking
     on the posix acl stored in the uapi format is really unreliable.
     The vfs currently hacks around directly in the uapi struct storing
     values that frankly the security and integrity modules can't
     correctly interpret as evidenced by bugs we reported and fixed in
     this area. It's not necessarily even their fault it's just that the
     format we provide to them is sub optimal.

   - Some filesystems like 9p and cifs need access to the dentry in
     order to get and set posix acls which is why they either only
     partially or not even at all implement get and set inode
     operations. For example, cifs allows setxattr() and getxattr()
     operations but doesn't allow permission checking based on posix
     acls because it can't implement a get acl inode operation.

     Thus, this patch series updates the set acl inode operation to take
     a dentry instead of an inode argument. However, for the get acl
     inode operation we can't do this as the old get acl method is
     called in e.g., generic_permission() and inode_permission(). These
     helpers in turn are called in various filesystem's permission inode
     operation. So passing a dentry argument to the old get acl inode
     operation would amount to passing a dentry to the permission inode
     operation which we shouldn't and probably can't do.

     So instead of extending the existing inode operation Christoph
     suggested to add a new one. He also requested to ensure that the
     get and set acl inode operation taking a dentry are consistently
     named. So for this version the old get acl operation is renamed to
     ->get_inode_acl() and a new ->get_acl() inode operation taking a
     dentry is added. With this we can give both 9p and cifs get and set
     acl inode operations and in turn remove their complex custom posix
     xattr handlers.

     In the future I hope to get rid of the inode method duplication but
     it isn't like we have never had this situation. Readdir is just one
     example. And frankly, the overall gain in type safety and the more
     pleasant api wise are simply too big of a benefit to not accept
     this duplication for a while.

   - We've done a full audit of every codepaths using variant of the
     current generic xattr api to get and set posix acls and
     surprisingly it isn't that many places. There's of course always a
     chance that we might have missed some and if so I'm sure we'll find
     them soon enough.

     The crucial codepaths to be converted are obviously stacking
     filesystems such as ecryptfs and overlayfs.

     For a list of all callers currently using generic xattr api helpers
     see [2] including comments whether they support posix acls or not.

   - The old vfs generic posix acl infrastructure doesn't obey the
     create and replace semantics promised on the setxattr(2) manpage.
     This patch series doesn't address this. It really is something we
     should revisit later though.

  The patches are roughly organized as follows:

   (1) Change existing set acl inode operation to take a dentry
       argument (Intended to be a non-functional change)

   (2) Rename existing get acl method (Intended to be a non-functional
       change)

   (3) Implement get and set acl inode operations for filesystems that
       couldn't implement one before because of the missing dentry.
       That's mostly 9p and cifs (Intended to be a non-functional
       change)

   (4) Build posix acl api, i.e., add vfs_get_acl(), vfs_remove_acl(),
       and vfs_set_acl() including security and integrity hooks
       (Intended to be a non-functional change)

   (5) Implement get and set acl inode operations for stacking
       filesystems (Intended to be a non-functional change)

   (6) Switch posix acl handling in stacking filesystems to new posix
       acl api now that all filesystems it can stack upon support it.

   (7) Switch vfs to new posix acl api (semantical change)

   (8) Remove all now unused helpers

   (9) Additional regression fixes reported after we merged this into
       linux-next

  Thanks to Seth for a lot of good discussion around this and
  encouragement and input from Christoph"

* tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (36 commits)
  posix_acl: Fix the type of sentinel in get_acl
  orangefs: fix mode handling
  ovl: call posix_acl_release() after error checking
  evm: remove dead code in evm_inode_set_acl()
  cifs: check whether acl is valid early
  acl: make vfs_posix_acl_to_xattr() static
  acl: remove a slew of now unused helpers
  9p: use stub posix acl handlers
  cifs: use stub posix acl handlers
  ovl: use stub posix acl handlers
  ecryptfs: use stub posix acl handlers
  evm: remove evm_xattr_acl_change()
  xattr: use posix acl api
  ovl: use posix acl api
  ovl: implement set acl method
  ovl: implement get acl method
  ecryptfs: implement set acl method
  ecryptfs: implement get acl method
  ksmbd: use vfs_remove_acl()
  acl: add vfs_remove_acl()
  ...
2022-12-12 18:46:39 -08:00
Paul Moore 048be15649 selinux: remove the sidtab context conversion indirect calls
The sidtab conversion code has support for multiple context
conversion routines through the use of function pointers and
indirect calls.  However, the reality is that all current users rely
on the same conversion routine: convert_context().  This patch does
away with this extra complexity and replaces the indirect calls
with direct function calls; allowing us to remove a layer of
obfuscation and create cleaner, more maintainable code.

Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-11-09 11:00:49 -05:00
Paul Moore b10b9c342f lsm: make security_socket_getpeersec_stream() sockptr_t safe
Commit 4ff09db1b7 ("bpf: net: Change sk_getsockopt() to take the
sockptr_t argument") made it possible to call sk_getsockopt()
with both user and kernel address space buffers through the use of
the sockptr_t type.  Unfortunately at the time of conversion the
security_socket_getpeersec_stream() LSM hook was written to only
accept userspace buffers, and in a desire to avoid having to change
the LSM hook the commit author simply passed the sockptr_t's
userspace buffer pointer.  Since the only sk_getsockopt() callers
at the time of conversion which used kernel sockptr_t buffers did
not allow SO_PEERSEC, and hence the
security_socket_getpeersec_stream() hook, this was acceptable but
also very fragile as future changes presented the possibility of
silently passing kernel space pointers to the LSM hook.

There are several ways to protect against this, including careful
code review of future commits, but since relying on code review to
catch bugs is a recipe for disaster and the upstream eBPF maintainer
is "strongly against defensive programming", this patch updates the
LSM hook, and all of the implementations to support sockptr_t and
safely handle both user and kernel space buffers.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-11-04 23:25:30 -04:00
Christian Brauner 1bdeb21862
selinux: implement get, set and remove acl hook
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

So far posix acls were passed as a void blob to the security and
integrity modules. Some of them like evm then proceed to interpret the
void pointer and convert it into the kernel internal struct posix acl
representation to perform their integrity checking magic. This is
obviously pretty problematic as that requires knowledge that only the
vfs is guaranteed to have and has lead to various bugs. Add a proper
security hook for setting posix acls and pass down the posix acls in
their appropriate vfs format instead of hacking it through a void
pointer stored in the uapi format.

I spent considerate time in the security module infrastructure and
audited all codepaths. SELinux has no restrictions based on the posix
acl values passed through it. The capability hook doesn't need to be
called either because it only has restrictions on security.* xattrs. So
these are all fairly simply hooks for SELinux.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:28 +02:00
GONG, Ruiqi abe3c63144 selinux: enable use of both GFP_KERNEL and GFP_ATOMIC in convert_context()
The following warning was triggered on a hardware environment:

  SELinux: Converting 162 SID table entries...
  BUG: sleeping function called from invalid context at
       __might_sleep+0x60/0x74 0x0
  in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 5943, name: tar
  CPU: 7 PID: 5943 Comm: tar Tainted: P O 5.10.0 #1
  Call trace:
   dump_backtrace+0x0/0x1c8
   show_stack+0x18/0x28
   dump_stack+0xe8/0x15c
   ___might_sleep+0x168/0x17c
   __might_sleep+0x60/0x74
   __kmalloc_track_caller+0xa0/0x7dc
   kstrdup+0x54/0xac
   convert_context+0x48/0x2e4
   sidtab_context_to_sid+0x1c4/0x36c
   security_context_to_sid_core+0x168/0x238
   security_context_to_sid_default+0x14/0x24
   inode_doinit_use_xattr+0x164/0x1e4
   inode_doinit_with_dentry+0x1c0/0x488
   selinux_d_instantiate+0x20/0x34
   security_d_instantiate+0x70/0xbc
   d_splice_alias+0x4c/0x3c0
   ext4_lookup+0x1d8/0x200 [ext4]
   __lookup_slow+0x12c/0x1e4
   walk_component+0x100/0x200
   path_lookupat+0x88/0x118
   filename_lookup+0x98/0x130
   user_path_at_empty+0x48/0x60
   vfs_statx+0x84/0x140
   vfs_fstatat+0x20/0x30
   __se_sys_newfstatat+0x30/0x74
   __arm64_sys_newfstatat+0x1c/0x2c
   el0_svc_common.constprop.0+0x100/0x184
   do_el0_svc+0x1c/0x2c
   el0_svc+0x20/0x34
   el0_sync_handler+0x80/0x17c
   el0_sync+0x13c/0x140
  SELinux: Context system_u:object_r:pssp_rsyslog_log_t:s0:c0 is
           not valid (left unmapped).

It was found that within a critical section of spin_lock_irqsave in
sidtab_context_to_sid(), convert_context() (hooked by
sidtab_convert_params.func) might cause the process to sleep via
allocating memory with GFP_KERNEL, which is problematic.

As Ondrej pointed out [1], convert_context()/sidtab_convert_params.func
has another caller sidtab_convert_tree(), which is okay with GFP_KERNEL.
Therefore, fix this problem by adding a gfp_t argument for
convert_context()/sidtab_convert_params.func and pass GFP_KERNEL/_ATOMIC
properly in individual callers.

Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20221018120111.1474581-1-gongruiqi1@huawei.com/ [1]
Reported-by: Tan Ninghao <tanninghao1@huawei.com>
Fixes: ee1a84fdfe ("selinux: overhaul sidtab to fix bug and improve performance")
Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
Reviewed-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: wrap long BUG() output lines, tweak subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-10-19 09:55:53 -04:00
Paul Moore e0d8259355 selinux: increase the deprecation sleep for checkreqprot and runtime disable
Further the checkreqprot and runtime disable deprecation efforts by
increasing the sleep time from 5 to 15 seconds to help make this more
noticeable for any users who are still using these knobs.

Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-10-17 16:15:30 -04:00
Linus Torvalds 4c0ed7d8d6 whack-a-mole: constifying struct path *
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Merge tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs constification updates from Al Viro:
 "whack-a-mole: constifying struct path *"

* tag 'pull-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ecryptfs: constify path
  spufs: constify path
  nd_jump_link(): constify path
  audit_init_parent(): constify path
  __io_setxattr(): constify path
  do_proc_readlink(): constify path
  overlayfs: constify path
  fs/notify: constify path
  may_linkat(): constify path
  do_sys_name_to_handle(): constify path
  ->getprocattr(): attribute name is const char *, TYVM...
2022-10-06 17:31:02 -07:00
Linus Torvalds 26b84401da lsm/stable-6.1 PR 20221003
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Merge tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm

Pull LSM updates from Paul Moore:
 "Seven patches for the LSM layer and we've got a mix of trivial and
  significant patches. Highlights below, starting with the smaller bits
  first so they don't get lost in the discussion of the larger items:

   - Remove some redundant NULL pointer checks in the common LSM audit
     code.

   - Ratelimit the lockdown LSM's access denial messages.

     With this change there is a chance that the last visible lockdown
     message on the console is outdated/old, but it does help preserve
     the initial series of lockdown denials that started the denial
     message flood and my gut feeling is that these might be the more
     valuable messages.

   - Open userfaultfds as readonly instead of read/write.

     While this code obviously lives outside the LSM, it does have a
     noticeable impact on the LSMs with Ondrej explaining the situation
     in the commit description. It is worth noting that this patch
     languished on the VFS list for over a year without any comments
     (objections or otherwise) so I took the liberty of pulling it into
     the LSM tree after giving fair notice. It has been in linux-next
     since the end of August without any noticeable problems.

   - Add a LSM hook for user namespace creation, with implementations
     for both the BPF LSM and SELinux.

     Even though the changes are fairly small, this is the bulk of the
     diffstat as we are also including BPF LSM selftests for the new
     hook.

     It's also the most contentious of the changes in this pull request
     with Eric Biederman NACK'ing the LSM hook multiple times during its
     development and discussion upstream. While I've never taken NACK's
     lightly, I'm sending these patches to you because it is my belief
     that they are of good quality, satisfy a long-standing need of
     users and distros, and are in keeping with the existing nature of
     the LSM layer and the Linux Kernel as a whole.

     The patches in implement a LSM hook for user namespace creation
     that allows for a granular approach, configurable at runtime, which
     enables both monitoring and control of user namespaces. The general
     consensus has been that this is far preferable to the other
     solutions that have been adopted downstream including outright
     removal from the kernel, disabling via system wide sysctls, or
     various other out-of-tree mechanisms that users have been forced to
     adopt since we haven't been able to provide them an upstream
     solution for their requests. Eric has been steadfast in his
     objections to this LSM hook, explaining that any restrictions on
     the user namespace could have significant impact on userspace.
     While there is the possibility of impacting userspace, it is
     important to note that this solution only impacts userspace when it
     is requested based on the runtime configuration supplied by the
     distro/admin/user. Frederick (the pathset author), the LSM/security
     community, and myself have tried to work with Eric during
     development of this patchset to find a mutually acceptable
     solution, but Eric's approach and unwillingness to engage in a
     meaningful way have made this impossible. I have CC'd Eric directly
     on this pull request so he has a chance to provide his side of the
     story; there have been no objections outside of Eric's"

* tag 'lsm-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
  lockdown: ratelimit denial messages
  userfaultfd: open userfaultfds with O_RDONLY
  selinux: Implement userns_create hook
  selftests/bpf: Add tests verifying bpf lsm userns_create hook
  bpf-lsm: Make bpf_lsm_userns_create() sleepable
  security, lsm: Introduce security_create_user_ns()
  lsm: clean up redundant NULL pointer check
2022-10-03 17:51:52 -07:00
Linus Torvalds e816da29bc selinux/stable-6.1 PR 20221003
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Merge tag 'selinux-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull SELinux updates from Paul Moore:
 "Six SELinux patches, all are simple and easily understood, but a list
  of the highlights is below:

   - Use 'grep -E' instead of 'egrep' in the SELinux policy install
     script.

     Fun fact, this seems to be GregKH's *second* dedicated SELinux
     patch since we transitioned to git (ignoring merges, the SPDX
     stuff, and a trivial fs reference removal when lustre was yanked);
     the first was back in 2011 when selinuxfs was placed in
     /sys/fs/selinux. Oh, the memories ...

   - Convert the SELinux policy boolean values to use signed integer
     types throughout the SELinux kernel code.

     Prior to this we were using a mix of signed and unsigned integers
     which was probably okay in this particular case, but it is
     definitely not a good idea in general.

   - Remove a reference to the SELinux runtime disable functionality in
     /etc/selinux/config as we are in the process of deprecating that.

     See [1] for more background on this if you missed the previous
     notes on the deprecation.

   - Minor cleanups: remove unneeded variables and function parameter
     constification"

Link: https://github.com/SELinuxProject/selinux-kernel/wiki/DEPRECATE-runtime-disable [1]

* tag 'selinux-pr-20221003' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: remove runtime disable message in the install_policy.sh script
  selinux: use "grep -E" instead of "egrep"
  selinux: remove the unneeded result variable
  selinux: declare read-only parameters const
  selinux: use int arrays for boolean values
  selinux: remove an unneeded variable in sel_make_class_dir_entries()
2022-10-03 17:45:15 -07:00
Xu Panda 09b71adab0 selinux: remove the unneeded result variable
Return the value avc_has_perm() directly instead of storing it in
another redundant variable.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Xu Panda <xu.panda@zte.com.cn>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-09-14 07:47:27 -04:00
Al Viro c8e477c649 ->getprocattr(): attribute name is const char *, TYVM...
cast of ->d_name.name to char * is completely wrong - nothing is
allowed to modify its contents.

Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-09-01 17:34:39 -04:00
Christian Göttsche 6354324d8a selinux: declare read-only parameters const
Declare ebitmap, mls_level and mls_context parameters const where they
are only read from.  This allows callers to supply pointers to const
as arguments and increases readability.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-30 17:14:36 -04:00
Christian Göttsche c3fae2b2e6 selinux: use int arrays for boolean values
Do not cast pointers of signed integers to pointers of unsigned integers
and vice versa.

It should currently not be an issue since they hold SELinux boolean
values which should only contain either 0's or 1's, which should have
the same representation.

Reported by sparse:

  .../selinuxfs.c:1485:30: warning: incorrect type in assignment
                                    (different signedness)
  .../selinuxfs.c:1485:30:    expected unsigned int *
  .../selinuxfs.c:1485:30:    got int *[addressable] values
  .../selinuxfs.c:1402:48: warning: incorrect type in argument 3
                                    (different signedness)
  .../selinuxfs.c:1402:48:    expected int *values
  .../selinuxfs.c:1402:48:    got unsigned int *bool_pending_values

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: minor whitespace fixes, sparse output cleanup]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-30 17:03:33 -04:00
ye xingchen 5698f08169 selinux: remove an unneeded variable in sel_make_class_dir_entries()
Return the value sel_make_perm_files() directly instead of storing it
in another redundant variable.

Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-30 16:26:01 -04:00
Paul Moore f4d653dcaa selinux: implement the security_uring_cmd() LSM hook
Add a SELinux access control for the iouring IORING_OP_URING_CMD
command.  This includes the addition of a new permission in the
existing "io_uring" object class: "cmd".  The subject of the new
permission check is the domain of the process requesting access, the
object is the open file which points to the device/file that is the
target of the IORING_OP_URING_CMD operation.  A sample policy rule
is shown below:

  allow <domain> <file>:io_uring { cmd };

Cc: stable@vger.kernel.org
Fixes: ee692a21e9 ("fs,io_uring: add infrastructure for uring-cmd")
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-26 11:19:43 -04:00
Frederick Lawler ed5d44d42c selinux: Implement userns_create hook
Unprivileged user namespace creation is an intended feature to enable
sandboxing, however this feature is often used to as an initial step to
perform a privilege escalation attack.

This patch implements a new user_namespace { create } access control
permission to restrict which domains allow or deny user namespace
creation. This is necessary for system administrators to quickly protect
their systems while waiting for vulnerability patches to be applied.

This permission can be used in the following way:

        allow domA_t domA_t : user_namespace { create };

Signed-off-by: Frederick Lawler <fred@cloudflare.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-08-16 17:44:44 -04:00
Linus Torvalds 79802ada87 selinux/stable-6.0 PR 20220801
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Merge tag 'selinux-pr-20220801' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "A relatively small set of patches for SELinux this time, eight patches
  in total with really only one significant change.

  The highlights are:

   - Add support for proper labeling of memfd_secret anonymous inodes.

     This will allow LSMs that implement the anonymous inode hooks to
     apply security policy to memfd_secret() fds.

   - Various small improvements to memory management: fixed leaks, freed
     memory when needed, boundary checks.

   - Hardened the selinux_audit_data struct with __randomize_layout.

   - A minor documentation tweak to fix a formatting/style issue"

* tag 'selinux-pr-20220801' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: selinux_add_opt() callers free memory
  selinux: Add boundary check in put_entry()
  selinux: fix memleak in security_read_state_kernel()
  docs: selinux: add '=' signs to kernel boot options
  mm: create security context for memfd_secret inodes
  selinux: fix typos in comments
  selinux: drop unnecessary NULL check
  selinux: add __randomize_layout to selinux_audit_data
2022-08-02 14:51:47 -07:00
Xiu Jianfeng ef54ccb616 selinux: selinux_add_opt() callers free memory
The selinux_add_opt() function may need to allocate memory for the
mount options if none has already been allocated, but there is no
need to free that memory on error as the callers handle that.  Drop
the existing kfree() on error to help increase consistency in the
selinux_add_opt() error handling.

This patch also changes selinux_add_opt() to return -EINVAL when
the mount option value, @s, is NULL.  It currently return -ENOMEM.

Link: https://lore.kernel.org/lkml/20220611090550.135674-1-xiujianfeng@huawei.com/T/
Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: fix subject, rework commit description language]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-20 21:05:40 -04:00
Christian Göttsche cad140d008 selinux: free contexts previously transferred in selinux_add_opt()
`selinux_add_opt()` stopped taking ownership of the passed context since
commit 70f4169ab4 ("selinux: parse contexts for mount options early").

    unreferenced object 0xffff888114dfd140 (size 64):
      comm "mount", pid 15182, jiffies 4295687028 (age 796.340s)
      hex dump (first 32 bytes):
        73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
        72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65  r:test_filesyste
      backtrace:
        [<ffffffffa07dbef4>] kmemdup_nul+0x24/0x80
        [<ffffffffa0d34253>] selinux_sb_eat_lsm_opts+0x293/0x560
        [<ffffffffa0d13f08>] security_sb_eat_lsm_opts+0x58/0x80
        [<ffffffffa0af1eb2>] generic_parse_monolithic+0x82/0x180
        [<ffffffffa0a9c1a5>] do_new_mount+0x1f5/0x550
        [<ffffffffa0a9eccb>] path_mount+0x2ab/0x1570
        [<ffffffffa0aa019e>] __x64_sys_mount+0x20e/0x280
        [<ffffffffa1f47124>] do_syscall_64+0x34/0x80
        [<ffffffffa200007e>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

    unreferenced object 0xffff888108e71640 (size 64):
      comm "fsmount", pid 7607, jiffies 4295044974 (age 1601.016s)
      hex dump (first 32 bytes):
        73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
        72 3a 74 65 73 74 5f 66 69 6c 65 73 79 73 74 65  r:test_filesyste
      backtrace:
        [<ffffffff861dc2b1>] memdup_user+0x21/0x90
        [<ffffffff861dc367>] strndup_user+0x47/0xa0
        [<ffffffff864f6965>] __do_sys_fsconfig+0x485/0x9f0
        [<ffffffff87940124>] do_syscall_64+0x34/0x80
        [<ffffffff87a0007e>] entry_SYSCALL_64_after_hwframe+0x46/0xb0

Cc: stable@vger.kernel.org
Fixes: 70f4169ab4 ("selinux: parse contexts for mount options early")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-15 21:20:45 -04:00
Xiu Jianfeng 15ec76fb29 selinux: Add boundary check in put_entry()
Just like next_entry(), boundary check is necessary to prevent memory
out-of-bound access.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-14 21:52:37 -04:00
Xiu Jianfeng 73de1befcc selinux: fix memleak in security_read_state_kernel()
In this function, it directly returns the result of __security_read_policy
without freeing the allocated memory in *data, cause memory leak issue,
so free the memory if __security_read_policy failed.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-13 19:31:53 -04:00
Jonas Lindner 9691e4f9ba selinux: fix typos in comments
Signed-off-by: Jonas Lindner <jolindner@gmx.de>
[PM: fixed duplicated subject line]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-10 15:49:15 -04:00
Christian Göttsche 4d3d0ed60e selinux: drop unnecessary NULL check
Commit e3489f8974 ("selinux: kill selinux_sb_get_mnt_opts()")
introduced a NULL check on the context after a successful call to
security_sid_to_context().  This is on the one hand redundant after
checking for success and on the other hand insufficient on an actual
NULL pointer, since the context is passed to seq_escape() leading to a
call of strlen() on it.

Reported by Clang analyzer:

    In file included from security/selinux/hooks.c:28:
    In file included from ./include/linux/tracehook.h:50:
    In file included from ./include/linux/memcontrol.h:13:
    In file included from ./include/linux/cgroup.h:18:
    ./include/linux/seq_file.h:136:25: warning: Null pointer passed as 1st argument to string length function [unix.cstring.NullArg]
            seq_escape_mem(m, src, strlen(src), flags, esc);
                                   ^~~~~~~~~~~

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-07 17:20:10 -04:00
GONG, Ruiqi 494688efdc selinux: add __randomize_layout to selinux_audit_data
Randomize the layout of struct selinux_audit_data as suggested in [1],
since it contains a pointer to struct selinux_state, an already
randomized strucure.

[1]: https://github.com/KSPP/linux/issues/188

Signed-off-by: GONG, Ruiqi <gongruiqi1@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-06-07 16:03:21 -04:00
Linus Torvalds efd1df1982 selinux/stable-5.19 PR 20220523
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Merge tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux

Pull selinux updates from Paul Moore:
 "We've got twelve patches queued for v5.19, with most being fairly
  minor. The highlights are below:

   - The checkreqprot and runtime disable knobs have been deprecated for
     some time with no active users that we can find. In an effort to
     move things along we are adding a pause when the knobs are used to
     help make the deprecation more noticeable in case anyone is still
     using these hacks in the shadows.

   - We've added the anonymous inode class name to the AVC audit records
     when anonymous inodes are involved. This should make writing policy
     easier when anonymous inodes are involved.

   - More constification work. This is fairly straightforward and the
     source of most of the diffstat.

   - The usual minor cleanups: remove unnecessary assignments, assorted
     style/checkpatch fixes, kdoc fixes, macro while-loop
     encapsulations, #include tweaks, etc"

* tag 'selinux-pr-20220523' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  security: declare member holding string literal const
  selinux: log anon inode class name
  selinux: declare data arrays const
  selinux: fix indentation level of mls_ops block
  selinux: include necessary headers in headers
  selinux: avoid extra semicolon
  selinux: update parameter documentation
  selinux: resolve checkpatch errors
  selinux: don't sleep when CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE is true
  selinux: checkreqprot is deprecated, add some ssleep() discomfort
  selinux: runtime disable is deprecated, add some ssleep() discomfort
  selinux: Remove redundant assignments
2022-05-24 13:06:32 -07:00
Ondrej Mosnacek 6254bd3db3 selinux: fix bad cleanup on error in hashtab_duplicate()
The code attempts to free the 'new' pointer using kmem_cache_free(),
which is wrong because this function isn't responsible of freeing it.
Instead, the function should free new->htable and clear the contents of
*new (to prevent double-free).

Cc: stable@vger.kernel.org
Fixes: c7c556f1e8 ("selinux: refactor changing booleans")
Reported-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-17 18:34:35 -04:00
Christian Göttsche c29722fad4 selinux: log anon inode class name
Log the anonymous inode class name in the security hook
inode_init_security_anon.  This name is the key for name based type
transitions on the anon_inode security class on creation.  Example:

    type=AVC msg=audit(02/16/22 22:02:50.585:216) : avc:  granted \
        { create } for  pid=2136 comm=mariadbd anonclass=[io_uring] \
        scontext=system_u:system_r:mysqld_t:s0 \
        tcontext=system_u:system_r:mysqld_iouring_t:s0 tclass=anon_inode

Add a new LSM audit data type holding the inode and the class name.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: adjusted 'anonclass' to be a trusted string, cgzones approved]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 16:09:03 -04:00
Christian Göttsche ded34574d4 selinux: declare data arrays const
The arrays for the policy capability names, the initial sid identifiers
and the class and permission names are not changed at runtime.  Declare
them const to avoid accidental modification.

Do not override the classmap and the initial sid list in the build time
script genheaders.

Check flose(3) is successful in genheaders.c, otherwise the written data
might be corrupted or incomplete.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: manual merge due to fuzz, minor style tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 15:53:49 -04:00
Christian Göttsche a9029d9704 selinux: fix indentation level of mls_ops block
Add one level of indentation to the code block of the label mls_ops in
constraint_expr_eval(), to adjust the trailing break; to the parent
case: branch.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 14:26:53 -04:00
Christian Göttsche 4ad37de496 selinux: include necessary headers in headers
Include header files required for struct or typedef declarations in
header files.  This is for example helpful when working with an IDE, which
needs to resolve those symbols.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 14:11:13 -04:00
Christian Göttsche 1d4e8036cb selinux: avoid extra semicolon
Wrap macro into `do { } while (0)` to avoid Clang emitting warnings
about extra semicolons.
Similar to userspace commit
9d85aa60d1

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: whitespace/indenting tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 14:07:11 -04:00
Christian Göttsche 759205151c selinux: update parameter documentation
security/selinux/include/audit.h:54: warning: Function parameter or member 'krule' not described in 'selinux_audit_rule_known'
security/selinux/include/audit.h:54: warning: Excess function parameter 'rule' description in 'selinux_audit_rule_known'
security/selinux/include/avc.h:130: warning: Function parameter or member 'state' not described in 'avc_audit'

This also bring the parameter name of selinux_audit_rule_known() in sync
between declaration and definition.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
2022-05-03 14:03:57 -04:00