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Merge tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull lsm updates from Paul Moore:
- Move the LSM framework to static calls
This transitions the vast majority of the LSM callbacks into static
calls. Those callbacks which haven't been converted were left as-is
due to the general ugliness of the changes required to support the
static call conversion; we can revisit those callbacks at a future
date.
- Add the Integrity Policy Enforcement (IPE) LSM
This adds a new LSM, Integrity Policy Enforcement (IPE). There is
plenty of documentation about IPE in this patches, so I'll refrain
from going into too much detail here, but the basic motivation behind
IPE is to provide a mechanism such that administrators can restrict
execution to only those binaries which come from integrity protected
storage, e.g. a dm-verity protected filesystem. You will notice that
IPE requires additional LSM hooks in the initramfs, dm-verity, and
fs-verity code, with the associated patches carrying ACK/review tags
from the associated maintainers. We couldn't find an obvious
maintainer for the initramfs code, but the IPE patchset has been
widely posted over several years.
Both Deven Bowers and Fan Wu have contributed to IPE's development
over the past several years, with Fan Wu agreeing to serve as the IPE
maintainer moving forward. Once IPE is accepted into your tree, I'll
start working with Fan to ensure he has the necessary accounts, keys,
etc. so that he can start submitting IPE pull requests to you
directly during the next merge window.
- Move the lifecycle management of the LSM blobs to the LSM framework
Management of the LSM blobs (the LSM state buffers attached to
various kernel structs, typically via a void pointer named "security"
or similar) has been mixed, some blobs were allocated/managed by
individual LSMs, others were managed by the LSM framework itself.
Starting with this pull we move management of all the LSM blobs,
minus the XFRM blob, into the framework itself, improving consistency
across LSMs, and reducing the amount of duplicated code across LSMs.
Due to some additional work required to migrate the XFRM blob, it has
been left as a todo item for a later date; from a practical
standpoint this omission should have little impact as only SELinux
provides a XFRM LSM implementation.
- Fix problems with the LSM's handling of F_SETOWN
The LSM hook for the fcntl(F_SETOWN) operation had a couple of
problems: it was racy with itself, and it was disconnected from the
associated DAC related logic in such a way that the LSM state could
be updated in cases where the DAC state would not. We fix both of
these problems by moving the security_file_set_fowner() hook into the
same section of code where the DAC attributes are updated. Not only
does this resolve the DAC/LSM synchronization issue, but as that code
block is protected by a lock, it also resolve the race condition.
- Fix potential problems with the security_inode_free() LSM hook
Due to use of RCU to protect inodes and the placement of the LSM hook
associated with freeing the inode, there is a bit of a challenge when
it comes to managing any LSM state associated with an inode. The VFS
folks are not open to relocating the LSM hook so we have to get
creative when it comes to releasing an inode's LSM state.
Traditionally we have used a single LSM callback within the hook that
is triggered when the inode is "marked for death", but not actually
released due to RCU.
Unfortunately, this causes problems for LSMs which want to take an
action when the inode's associated LSM state is actually released; so
we add an additional LSM callback, inode_free_security_rcu(), that is
called when the inode's LSM state is released in the RCU free
callback.
- Refactor two LSM hooks to better fit the LSM return value patterns
The vast majority of the LSM hooks follow the "return 0 on success,
negative values on failure" pattern, however, there are a small
handful that have unique return value behaviors which has caused
confusion in the past and makes it difficult for the BPF verifier to
properly vet BPF LSM programs. This includes patches to
convert two of these"special" LSM hooks to the common 0/-ERRNO pattern.
- Various cleanups and improvements
A handful of patches to remove redundant code, better leverage the
IS_ERR_OR_NULL() helper, add missing "static" markings, and do some
minor style fixups.
* tag 'lsm-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm: (40 commits)
security: Update file_set_fowner documentation
fs: Fix file_set_fowner LSM hook inconsistencies
lsm: Use IS_ERR_OR_NULL() helper function
lsm: remove LSM_COUNT and LSM_CONFIG_COUNT
ipe: Remove duplicated include in ipe.c
lsm: replace indirect LSM hook calls with static calls
lsm: count the LSMs enabled at compile time
kernel: Add helper macros for loop unrolling
init/main.c: Initialize early LSMs after arch code, static keys and calls.
MAINTAINERS: add IPE entry with Fan Wu as maintainer
documentation: add IPE documentation
ipe: kunit test for parser
scripts: add boot policy generation program
ipe: enable support for fs-verity as a trust provider
fsverity: expose verified fsverity built-in signatures to LSMs
lsm: add security_inode_setintegrity() hook
ipe: add support for dm-verity as a trust provider
dm-verity: expose root hash digest and signature data to LSMs
block,lsm: add LSM blob and new LSM hooks for block devices
ipe: add permissive toggle
...
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Merge tag 'selinux-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux
Pull selinux updates from Paul Moore:
- Ensure that both IPv4 and IPv6 connections are properly initialized
While we always properly initialized IPv4 connections early in their
life, we missed the necessary IPv6 change when we were adding IPv6
support.
- Annotate the SELinux inode revalidation function to quiet KCSAN
KCSAN correctly identifies a race in __inode_security_revalidate()
when we check to see if an inode's SELinux has been properly
initialized. While KCSAN is correct, it is an intentional choice made
for performance reasons; if necessary, we check the state a second
time, this time with a lock held, before initializing the inode's
state.
- Code cleanups, simplification, etc.
A handful of individual patches to simplify some SELinux kernel
logic, improve return code granularity via ERR_PTR(), follow the
guidance on using KMEM_CACHE(), and correct some minor style
problems.
* tag 'selinux-pr-20240911' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
selinux: fix style problems in security/selinux/include/audit.h
selinux: simplify avc_xperms_audit_required()
selinux: mark both IPv4 and IPv6 accepted connection sockets as labeled
selinux: replace kmem_cache_create() with KMEM_CACHE()
selinux: annotate false positive data race to avoid KCSAN warnings
selinux: refactor code to return ERR_PTR in selinux_netlbl_sock_genattr
selinux: Streamline type determination in security_compute_sid
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Merge tag 'vfs-6.12.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull procfs updates from Christian Brauner:
"This contains the following changes for procfs:
- Add config options and parameters to block forcing memory writes.
This adds a Kconfig option and boot param to allow removing the
FOLL_FORCE flag from /proc/<pid>/mem write calls as this can be
used in various attacks.
The traditional forcing behavior is kept as default because it can
break GDB and some other use cases.
This is the simpler version that you had requested.
- Restrict overmounting of ephemeral entities.
It is currently possible to mount on top of various ephemeral
entities in procfs. This specifically includes magic links. To
recap, magic links are links of the form /proc/<pid>/fd/<nr>. They
serve as references to a target file and during path lookup they
cause a jump to the target path. Such magic links disappear if the
corresponding file descriptor is closed.
Currently it is possible to overmount such magic links. This is
mostly interesting for an attacker that wants to somehow trick a
process into e.g., reopening something that it didn't intend to
reopen or to hide a malicious file descriptor.
But also it risks leaking mounts for long-running processes. When
overmounting a magic link like above, the mount will not be
detached when the file descriptor is closed. Only the target
mountpoint will disappear. Which has the consequence of making it
impossible to unmount that mount afterwards. So the mount will
stick around until the process exits and the /proc/<pid>/ directory
is cleaned up during proc_flush_pid() when the dentries are pruned
and invalidated.
That in turn means it's possible for a program to accidentally leak
mounts and it's also possible to make a task leak mounts without
it's knowledge if the attacker just keeps overmounting things under
/proc/<pid>/fd/<nr>.
Disallow overmounting of such ephemeral entities.
- Cleanup the readdir method naming in some procfs file operations.
- Replace kmalloc() and strcpy() with a simple kmemdup() call"
* tag 'vfs-6.12.procfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
proc: fold kmalloc() + strcpy() into kmemdup()
proc: block mounting on top of /proc/<pid>/fdinfo/*
proc: block mounting on top of /proc/<pid>/fd/*
proc: block mounting on top of /proc/<pid>/map_files/*
proc: add proc_splice_unmountable()
proc: proc_readfdinfo() -> proc_fdinfo_iterate()
proc: proc_readfd() -> proc_fd_iterate()
proc: add config & param to block forcing mem writes
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Merge tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs file updates from Christian Brauner:
"This is the work to cleanup and shrink struct file significantly.
Right now, (focusing on x86) struct file is 232 bytes. After this
series struct file will be 184 bytes aka 3 cacheline and a spare 8
bytes for future extensions at the end of the struct.
With struct file being as ubiquitous as it is this should make a
difference for file heavy workloads and allow further optimizations in
the future.
- struct fown_struct was embedded into struct file letting it take up
32 bytes in total when really it shouldn't even be embedded in
struct file in the first place. Instead, actual users of struct
fown_struct now allocate the struct on demand. This frees up 24
bytes.
- Move struct file_ra_state into the union containg the cleanup hooks
and move f_iocb_flags out of the union. This closes a 4 byte hole
we created earlier and brings struct file to 192 bytes. Which means
struct file is 3 cachelines and we managed to shrink it by 40
bytes.
- Reorder struct file so that nothing crosses a cacheline.
I suspect that in the future we will end up reordering some members
to mitigate false sharing issues or just because someone does
actually provide really good perf data.
- Shrinking struct file to 192 bytes is only part of the work.
Files use a slab that is SLAB_TYPESAFE_BY_RCU and when a kmem cache
is created with SLAB_TYPESAFE_BY_RCU the free pointer must be
located outside of the object because the cache doesn't know what
part of the memory can safely be overwritten as it may be needed to
prevent object recycling.
That has the consequence that SLAB_TYPESAFE_BY_RCU may end up
adding a new cacheline.
So this also contains work to add a new kmem_cache_create_rcu()
function that allows the caller to specify an offset where the
freelist pointer is supposed to be placed. Thus avoiding the
implicit addition of a fourth cacheline.
- And finally this removes the f_version member in struct file.
The f_version member isn't particularly well-defined. It is mainly
used as a cookie to detect concurrent seeks when iterating
directories. But it is also abused by some subsystems for
completely unrelated things.
It is mostly a directory and filesystem specific thing that doesn't
really need to live in struct file and with its wonky semantics it
really lacks a specific function.
For pipes, f_version is (ab)used to defer poll notifications until
a write has happened. And struct pipe_inode_info is used by
multiple struct files in their ->private_data so there's no chance
of pushing that down into file->private_data without introducing
another pointer indirection.
But pipes don't rely on f_pos_lock so this adds a union into struct
file encompassing f_pos_lock and a pipe specific f_pipe member that
pipes can use. This union of course can be extended to other file
types and is similar to what we do in struct inode already"
* tag 'vfs-6.12.file' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits)
fs: remove f_version
pipe: use f_pipe
fs: add f_pipe
ubifs: store cookie in private data
ufs: store cookie in private data
udf: store cookie in private data
proc: store cookie in private data
ocfs2: store cookie in private data
input: remove f_version abuse
ext4: store cookie in private data
ext2: store cookie in private data
affs: store cookie in private data
fs: add generic_llseek_cookie()
fs: use must_set_pos()
fs: add must_set_pos()
fs: add vfs_setpos_cookie()
s390: remove unused f_version
ceph: remove unused f_version
adi: remove unused f_version
mm: Removed @freeptr_offset to prevent doc warning
...
Highlight that the file_set_fowner hook is now called with a lock held.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: Jann Horn <jannh@google.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Pull misc fixes from Guenter Roeck.
These are fixes for regressions that Guenther has been reporting, and
the maintainers haven't picked up and sent in. With rc6 fairly imminent,
I'm taking them directly from Guenter.
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
apparmor: fix policy_unpack_test on big endian systems
Revert "MIPS: csrc-r4k: Apply verification clocksource flags"
microblaze: don't treat zero reserved memory regions as error
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Merge tag 'lsm-pr-20240830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm
Pull lsm fix from Paul Moore:
"One small patch to correct a NFS permissions problem with SELinux and
Smack"
* tag 'lsm-pr-20240830' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/lsm:
selinux,smack: don't bypass permissions check in inode_setsecctx hook
This adds a Kconfig option and boot param to allow removing
the FOLL_FORCE flag from /proc/pid/mem write calls because
it can be abused.
The traditional forcing behavior is kept as default because
it can break GDB and some other use cases.
Previously we tried a more sophisticated approach allowing
distributions to fine-tune /proc/pid/mem behavior, however
that got NAK-ed by Linus [1], who prefers this simpler
approach with semantics also easier to understand for users.
Link: https://lore.kernel.org/lkml/CAHk-=wiGWLChxYmUA5HrT5aopZrB7_2VTa0NLZcxORgkUe5tEQ@mail.gmail.com/ [1]
Cc: Doug Anderson <dianders@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Link: https://lore.kernel.org/r/20240802080225.89408-1-adrian.ratiu@collabora.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Use the IS_ERR_OR_NULL() helper instead of open-coding a
NULL and an error pointer checks to simplify the code and
improve readability.
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Marek Gresko reports that the root user on an NFS client is able to
change the security labels on files on an NFS filesystem that is
exported with root squashing enabled.
The end of the kerneldoc comment for __vfs_setxattr_noperm() states:
* This function requires the caller to lock the inode's i_mutex before it
* is executed. It also assumes that the caller will make the appropriate
* permission checks.
nfsd_setattr() does do permissions checking via fh_verify() and
nfsd_permission(), but those don't do all the same permissions checks
that are done by security_inode_setxattr() and its related LSM hooks do.
Since nfsd_setattr() is the only consumer of security_inode_setsecctx(),
simplest solution appears to be to replace the call to
__vfs_setxattr_noperm() with a call to __vfs_setxattr_locked(). This
fixes the above issue and has the added benefit of causing nfsd to
recall conflicting delegations on a file when a client tries to change
its security label.
Cc: stable@kernel.org
Reported-by: Marek Gresko <marek.gresko@protonmail.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=218809
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Tested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
By associative and commutative laws, the result of the two 'audited' is
zero. Take the second 'audited' as an example:
1) audited = requested & avd->auditallow;
2) audited &= ~requested;
==> audited = ~requested & (requested & avd->auditallow);
==> audited = (~requested & requested) & avd->auditallow;
==> audited = 0 & avd->auditallow;
==> audited = 0;
In fact, it is more readable to directly write zero. The value of the
first 'audited' is 0 because AUDIT is not allowed. The second 'audited'
is zero because there is no AUDITALLOW permission.
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The current partial labeling was introduced in 389fb800ac ("netlabel:
Label incoming TCP connections correctly in SELinux") due to the fact
that IPv6 labeling was not supported yet at the time.
Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
[PM: properly format the referenced commit ID, adjust subject]
Signed-off-by: Paul Moore <paul@paul-moore.com>
We do embedd struct fown_struct into struct file letting it take up 32
bytes in total. We could tweak struct fown_struct to be more compact but
really it shouldn't even be embedded in struct file in the first place.
Instead, actual users of struct fown_struct should allocate the struct
on demand. This frees up 24 bytes in struct file.
That will have some potentially user-visible changes for the ownership
fcntl()s. Some of them can now fail due to allocation failures.
Practically, that probably will almost never happen as the allocations
are small and they only happen once per file.
The fown_struct is used during kill_fasync() which is used by e.g.,
pipes to generate a SIGIO signal. Sending of such signals is conditional
on userspace having set an owner for the file using one of the F_OWNER
fcntl()s. Such users will be unaffected if struct fown_struct is
allocated during the fcntl() call.
There are a few subsystems that call __f_setown() expecting
file->f_owner to be allocated:
(1) tun devices
file->f_op->fasync::tun_chr_fasync()
-> __f_setown()
There are no callers of tun_chr_fasync().
(2) tty devices
file->f_op->fasync::tty_fasync()
-> __tty_fasync()
-> __f_setown()
tty_fasync() has no additional callers but __tty_fasync() has. Note
that __tty_fasync() only calls __f_setown() if the @on argument is
true. It's called from:
file->f_op->release::tty_release()
-> tty_release()
-> __tty_fasync()
-> __f_setown()
tty_release() calls __tty_fasync() with @on false
=> __f_setown() is never called from tty_release().
=> All callers of tty_release() are safe as well.
file->f_op->release::tty_open()
-> tty_release()
-> __tty_fasync()
-> __f_setown()
__tty_hangup() calls __tty_fasync() with @on false
=> __f_setown() is never called from tty_release().
=> All callers of __tty_hangup() are safe as well.
From the callchains it's obvious that (1) and (2) end up getting called
via file->f_op->fasync(). That can happen either through the F_SETFL
fcntl() with the FASYNC flag raised or via the FIOASYNC ioctl(). If
FASYNC is requested and the file isn't already FASYNC then
file->f_op->fasync() is called with @on true which ends up causing both
(1) and (2) to call __f_setown().
(1) and (2) are the only subsystems that call __f_setown() from the
file->f_op->fasync() handler. So both (1) and (2) have been updated to
allocate a struct fown_struct prior to calling fasync_helper() to
register with the fasync infrastructure. That's safe as they both call
fasync_helper() which also does allocations if @on is true.
The other interesting case are file leases:
(3) file leases
lease_manager_ops->lm_setup::lease_setup()
-> __f_setown()
Which in turn is called from:
generic_add_lease()
-> lease_manager_ops->lm_setup::lease_setup()
-> __f_setown()
So here again we can simply make generic_add_lease() allocate struct
fown_struct prior to the lease_manager_ops->lm_setup::lease_setup()
which happens under a spinlock.
With that the two remaining subsystems that call __f_setown() are:
(4) dnotify
(5) sockets
Both have their own custom ioctls to set struct fown_struct and both
have been converted to allocate a struct fown_struct on demand from
their respective ioctls.
Interactions with O_PATH are fine as well e.g., when opening a /dev/tty
as O_PATH then no file->f_op->open() happens thus no file->f_owner is
allocated. That's fine as no file operation will be set for those and
the device has never been opened. fcntl()s called on such things will
just allocate a ->f_owner on demand. Although I have zero idea why'd you
care about f_owner on an O_PATH fd.
Link: https://lore.kernel.org/r/20240813-work-f_owner-v2-1-4e9343a79f9f@kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Based on guidance in include/linux/slab.h, replace kmem_cache_create()
with KMEM_CACHE() for sources under security/selinux to simplify creation
of SLAB caches.
Signed-off-by: Eric Suen <ericsu@linux.microsoft.com>
[PM: minor grammar nits in the description]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Because these are equals to MAX_LSM_COUNT. Also, we can avoid dynamic
memory allocation for ordered_lsms because MAX_LSM_COUNT is a constant.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul Moore <paul@paul-moore.com>
KCSAN flags the check of isec->initialized by
__inode_security_revalidate() as a data race. This is indeed a racy
check, but inode_doinit_with_dentry() will recheck with isec->lock held.
Annotate the check with the data_race() macro to silence the KCSAN false
positive.
Reported-by: syzbot+319ed1769c0078257262@syzkaller.appspotmail.com
Signed-off-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
policy_unpack_test fails on big endian systems because data byte order
is expected to be little endian but is generated in host byte order.
This results in test failures such as:
# policy_unpack_test_unpack_array_with_null_name: EXPECTATION FAILED at security/apparmor/policy_unpack_test.c:150
Expected array_size == (u16)16, but
array_size == 4096 (0x1000)
(u16)16 == 16 (0x10)
# policy_unpack_test_unpack_array_with_null_name: pass:0 fail:1 skip:0 total:1
not ok 3 policy_unpack_test_unpack_array_with_null_name
# policy_unpack_test_unpack_array_with_name: EXPECTATION FAILED at security/apparmor/policy_unpack_test.c:164
Expected array_size == (u16)16, but
array_size == 4096 (0x1000)
(u16)16 == 16 (0x10)
# policy_unpack_test_unpack_array_with_name: pass:0 fail:1 skip:0 total:1
Add the missing endianness conversions when generating test data.
Fixes: 4d944bcd4e ("apparmor: add AppArmor KUnit tests for policy unpack")
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
The header files eval.h is included twice in ipe.c,
so one inclusion of each can be removed.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9796
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
LSM hooks are currently invoked from a linked list as indirect calls
which are invoked using retpolines as a mitigation for speculative
attacks (Branch History / Target injection) and add extra overhead which
is especially bad in kernel hot paths:
security_file_ioctl:
0xff...0320 <+0>: endbr64
0xff...0324 <+4>: push %rbp
0xff...0325 <+5>: push %r15
0xff...0327 <+7>: push %r14
0xff...0329 <+9>: push %rbx
0xff...032a <+10>: mov %rdx,%rbx
0xff...032d <+13>: mov %esi,%ebp
0xff...032f <+15>: mov %rdi,%r14
0xff...0332 <+18>: mov $0xff...7030,%r15
0xff...0339 <+25>: mov (%r15),%r15
0xff...033c <+28>: test %r15,%r15
0xff...033f <+31>: je 0xff...0358 <security_file_ioctl+56>
0xff...0341 <+33>: mov 0x18(%r15),%r11
0xff...0345 <+37>: mov %r14,%rdi
0xff...0348 <+40>: mov %ebp,%esi
0xff...034a <+42>: mov %rbx,%rdx
0xff...034d <+45>: call 0xff...2e0 <__x86_indirect_thunk_array+352>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Indirect calls that use retpolines leading to overhead, not just due
to extra instruction but also branch misses.
0xff...0352 <+50>: test %eax,%eax
0xff...0354 <+52>: je 0xff...0339 <security_file_ioctl+25>
0xff...0356 <+54>: jmp 0xff...035a <security_file_ioctl+58>
0xff...0358 <+56>: xor %eax,%eax
0xff...035a <+58>: pop %rbx
0xff...035b <+59>: pop %r14
0xff...035d <+61>: pop %r15
0xff...035f <+63>: pop %rbp
0xff...0360 <+64>: jmp 0xff...47c4 <__x86_return_thunk>
The indirect calls are not really needed as one knows the addresses of
enabled LSM callbacks at boot time and only the order can possibly
change at boot time with the lsm= kernel command line parameter.
An array of static calls is defined per LSM hook and the static calls
are updated at boot time once the order has been determined.
With the hook now exposed as a static call, one can see that the
retpolines are no longer there and the LSM callbacks are invoked
directly:
security_file_ioctl:
0xff...0ca0 <+0>: endbr64
0xff...0ca4 <+4>: nopl 0x0(%rax,%rax,1)
0xff...0ca9 <+9>: push %rbp
0xff...0caa <+10>: push %r14
0xff...0cac <+12>: push %rbx
0xff...0cad <+13>: mov %rdx,%rbx
0xff...0cb0 <+16>: mov %esi,%ebp
0xff...0cb2 <+18>: mov %rdi,%r14
0xff...0cb5 <+21>: jmp 0xff...0cc7 <security_file_ioctl+39>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Static key enabled for SELinux
0xffffffff818f0cb7 <+23>: jmp 0xff...0cde <security_file_ioctl+62>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Static key enabled for BPF LSM. This is something that is changed to
default to false to avoid the existing side effect issues of BPF LSM
[1] in a subsequent patch.
0xff...0cb9 <+25>: xor %eax,%eax
0xff...0cbb <+27>: xchg %ax,%ax
0xff...0cbd <+29>: pop %rbx
0xff...0cbe <+30>: pop %r14
0xff...0cc0 <+32>: pop %rbp
0xff...0cc1 <+33>: cs jmp 0xff...0000 <__x86_return_thunk>
0xff...0cc7 <+39>: endbr64
0xff...0ccb <+43>: mov %r14,%rdi
0xff...0cce <+46>: mov %ebp,%esi
0xff...0cd0 <+48>: mov %rbx,%rdx
0xff...0cd3 <+51>: call 0xff...3230 <selinux_file_ioctl>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Direct call to SELinux.
0xff...0cd8 <+56>: test %eax,%eax
0xff...0cda <+58>: jne 0xff...0cbd <security_file_ioctl+29>
0xff...0cdc <+60>: jmp 0xff...0cb7 <security_file_ioctl+23>
0xff...0cde <+62>: endbr64
0xff...0ce2 <+66>: mov %r14,%rdi
0xff...0ce5 <+69>: mov %ebp,%esi
0xff...0ce7 <+71>: mov %rbx,%rdx
0xff...0cea <+74>: call 0xff...e220 <bpf_lsm_file_ioctl>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Direct call to BPF LSM.
0xff...0cef <+79>: test %eax,%eax
0xff...0cf1 <+81>: jne 0xff...0cbd <security_file_ioctl+29>
0xff...0cf3 <+83>: jmp 0xff...0cb9 <security_file_ioctl+25>
0xff...0cf5 <+85>: endbr64
0xff...0cf9 <+89>: mov %r14,%rdi
0xff...0cfc <+92>: mov %ebp,%esi
0xff...0cfe <+94>: mov %rbx,%rdx
0xff...0d01 <+97>: pop %rbx
0xff...0d02 <+98>: pop %r14
0xff...0d04 <+100>: pop %rbp
0xff...0d05 <+101>: ret
0xff...0d06 <+102>: int3
0xff...0d07 <+103>: int3
0xff...0d08 <+104>: int3
0xff...0d09 <+105>: int3
While this patch uses static_branch_unlikely indicating that an LSM hook
is likely to be not present. In most cases this is still a better choice
as even when an LSM with one hook is added, empty slots are created for
all LSM hooks (especially when many LSMs that do not initialize most
hooks are present on the system).
There are some hooks that don't use the call_int_hook or
call_void_hook. These hooks are updated to use a new macro called
lsm_for_each_hook where the lsm_callback is directly invoked as an
indirect call.
Below are results of the relevant Unixbench system benchmarks with BPF LSM
and SELinux enabled with default policies enabled with and without these
patches.
Benchmark Delta(%): (+ is better)
==========================================================================
Execl Throughput +1.9356
File Write 1024 bufsize 2000 maxblocks +6.5953
Pipe Throughput +9.5499
Pipe-based Context Switching +3.0209
Process Creation +2.3246
Shell Scripts (1 concurrent) +1.4975
System Call Overhead +2.7815
System Benchmarks Index Score (Partial Only): +3.4859
In the best case, some syscalls like eventfd_create benefitted to about
~10%.
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Song Liu <song@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: KP Singh <kpsingh@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Add various happy/unhappy unit tests for both IPE's policy parser.
Besides, a test suite for IPE functionality is available at
https://github.com/microsoft/ipe/tree/test-suite
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Enables an IPE policy to be enforced from kernel start, enabling access
control based on trust from kernel startup. This is accomplished by
transforming an IPE policy indicated by CONFIG_IPE_BOOT_POLICY into a
c-string literal that is parsed at kernel startup as an unsigned policy.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Enable IPE policy authors to indicate trust for a singular fsverity
file, identified by the digest information, through "fsverity_digest"
and all files using valid fsverity builtin signatures via
"fsverity_signature".
This enables file-level integrity claims to be expressed in IPE,
allowing individual files to be authorized, giving some flexibility
for policy authors. Such file-level claims are important to be expressed
for enforcing the integrity of packages, as well as address some of the
scalability issues in a sole dm-verity based solution (# of loop back
devices, etc).
This solution cannot be done in userspace as the minimum threat that
IPE should mitigate is an attacker downloads malicious payload with
all required dependencies. These dependencies can lack the userspace
check, bypassing the protection entirely. A similar attack succeeds if
the userspace component is replaced with a version that does not
perform the check. As a result, this can only be done in the common
entry point - the kernel.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch introduces a new hook to save inode's integrity
data. For example, for fsverity enabled files, LSMs can use this hook to
save the existence of verified fsverity builtin signature into the inode's
security blob, and LSMs can make access decisions based on this data.
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: subject line tweak, removed changelog]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Allows author of IPE policy to indicate trust for a singular dm-verity
volume, identified by roothash, through "dmverity_roothash" and all
signed and validated dm-verity volumes, through "dmverity_signature".
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: fixed some line length issues in the comments]
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch introduces a new LSM blob to the block_device structure,
enabling the security subsystem to store security-sensitive data related
to block devices. Currently, for a device mapper's mapped device containing
a dm-verity target, critical security information such as the roothash and
its signing state are not readily accessible. Specifically, while the
dm-verity volume creation process passes the dm-verity roothash and its
signature from userspace to the kernel, the roothash is stored privately
within the dm-verity target, and its signature is discarded
post-verification. This makes it extremely hard for the security subsystem
to utilize these data.
With the addition of the LSM blob to the block_device structure, the
security subsystem can now retain and manage important security metadata
such as the roothash and the signing state of a dm-verity by storing them
inside the blob. Access decisions can then be based on these stored data.
The implementation follows the same approach used for security blobs in
other structures like struct file, struct inode, and struct superblock.
The initialization of the security blob occurs after the creation of the
struct block_device, performed by the security subsystem. Similarly, the
security blob is freed by the security subsystem before the struct
block_device is deallocated or freed.
This patch also introduces a new hook security_bdev_setintegrity() to save
block device's integrity data to the new LSM blob. For example, for
dm-verity, it can use this hook to expose its roothash and signing state
to LSMs, then LSMs can save these data into the LSM blob.
Please note that the new hook should be invoked every time the security
information is updated to keep these data current. For example, in
dm-verity, if the mapping table is reloaded and configured to use a
different dm-verity target with a new roothash and signing information,
the previously stored data in the LSM blob will become obsolete. It is
crucial to re-invoke the hook to refresh these data and ensure they are up
to date. This necessity arises from the design of device-mapper, where a
device-mapper device is first created, and then targets are subsequently
loaded into it. These targets can be modified multiple times during the
device's lifetime. Therefore, while the LSM blob is allocated during the
creation of the block device, its actual contents are not initialized at
this stage and can change substantially over time. This includes
alterations from data that the LSM 'trusts' to those it does not, making
it essential to handle these changes correctly. Failure to address this
dynamic aspect could potentially allow for bypassing LSM checks.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: merge fuzz, subject line tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
IPE, like SELinux, supports a permissive mode. This mode allows policy
authors to test and evaluate IPE policy without it affecting their
programs. When the mode is changed, a 1404 AUDIT_MAC_STATUS will
be reported.
This patch adds the following audit records:
audit: MAC_STATUS enforcing=0 old_enforcing=1 auid=4294967295
ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1
audit: MAC_STATUS enforcing=1 old_enforcing=0 auid=4294967295
ses=4294967295 enabled=1 old-enabled=1 lsm=ipe res=1
The audit record only emit when the value from the user input is
different from the current enforce value.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Users of IPE require a way to identify when and why an operation fails,
allowing them to both respond to violations of policy and be notified
of potentially malicious actions on their systems with respect to IPE
itself.
This patch introduces 3 new audit events.
AUDIT_IPE_ACCESS(1420) indicates the result of an IPE policy evaluation
of a resource.
AUDIT_IPE_CONFIG_CHANGE(1421) indicates the current active IPE policy
has been changed to another loaded policy.
AUDIT_IPE_POLICY_LOAD(1422) indicates a new IPE policy has been loaded
into the kernel.
This patch also adds support for success auditing, allowing users to
identify why an allow decision was made for a resource. However, it is
recommended to use this option with caution, as it is quite noisy.
Here are some examples of the new audit record types:
AUDIT_IPE_ACCESS(1420):
audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1
pid=297 comm="sh" path="/root/vol/bin/hello" dev="tmpfs"
ino=3897 rule="op=EXECUTE boot_verified=TRUE action=ALLOW"
audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1
pid=299 comm="sh" path="/mnt/ipe/bin/hello" dev="dm-0"
ino=2 rule="DEFAULT action=DENY"
audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1
pid=300 path="/tmp/tmpdp2h1lub/deny/bin/hello" dev="tmpfs"
ino=131 rule="DEFAULT action=DENY"
The above three records were generated when the active IPE policy only
allows binaries from the initramfs to run. The three identical `hello`
binary were placed at different locations, only the first hello from
the rootfs(initramfs) was allowed.
Field ipe_op followed by the IPE operation name associated with the log.
Field ipe_hook followed by the name of the LSM hook that triggered the IPE
event.
Field enforcing followed by the enforcement state of IPE. (it will be
introduced in the next commit)
Field pid followed by the pid of the process that triggered the IPE
event.
Field comm followed by the command line program name of the process that
triggered the IPE event.
Field path followed by the file's path name.
Field dev followed by the device name as found in /dev where the file is
from.
Note that for device mappers it will use the name `dm-X` instead of
the name in /dev/mapper.
For a file in a temp file system, which is not from a device, it will use
`tmpfs` for the field.
The implementation of this part is following another existing use case
LSM_AUDIT_DATA_INODE in security/lsm_audit.c
Field ino followed by the file's inode number.
Field rule followed by the IPE rule made the access decision. The whole
rule must be audited because the decision is based on the combination of
all property conditions in the rule.
Along with the syscall audit event, user can know why a blocked
happened. For example:
audit: AUDIT1420 ipe_op=EXECUTE ipe_hook=BPRM_CHECK enforcing=1
pid=2138 comm="bash" path="/mnt/ipe/bin/hello" dev="dm-0"
ino=2 rule="DEFAULT action=DENY"
audit[1956]: SYSCALL arch=c000003e syscall=59
success=no exit=-13 a0=556790138df0 a1=556790135390 a2=5567901338b0
a3=ab2a41a67f4f1f4e items=1 ppid=147 pid=1956 auid=4294967295 uid=0
gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=pts0
ses=4294967295 comm="bash" exe="/usr/bin/bash" key=(null)
The above two records showed bash used execve to run "hello" and got
blocked by IPE. Note that the IPE records are always prior to a SYSCALL
record.
AUDIT_IPE_CONFIG_CHANGE(1421):
audit: AUDIT1421
old_active_pol_name="Allow_All" old_active_pol_version=0.0.0
old_policy_digest=sha256:E3B0C44298FC1C149AFBF4C8996FB92427AE41E4649
new_active_pol_name="boot_verified" new_active_pol_version=0.0.0
new_policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F
auid=4294967295 ses=4294967295 lsm=ipe res=1
The above record showed the current IPE active policy switch from
`Allow_All` to `boot_verified` along with the version and the hash
digest of the two policies. Note IPE can only have one policy active
at a time, all access decision evaluation is based on the current active
policy.
The normal procedure to deploy a policy is loading the policy to deploy
into the kernel first, then switch the active policy to it.
AUDIT_IPE_POLICY_LOAD(1422):
audit: AUDIT1422 policy_name="boot_verified" policy_version=0.0.0
policy_digest=sha256:820EEA5B40CA42B51F68962354BA083122A20BB846F2676
auid=4294967295 ses=4294967295 lsm=ipe res=1
The above record showed a new policy has been loaded into the kernel
with the policy name, policy version and policy hash.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
As is typical with LSMs, IPE uses securityfs as its interface with
userspace. for a complete list of the interfaces and the respective
inputs/outputs, please see the documentation under
admin-guide/LSM/ipe.rst
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
When deleting a directory in the security file system, the existing
securityfs_remove requires the directory to be empty, otherwise
it will do nothing. This leads to a potential risk that the security
file system might be in an unclean state when the intended deletion
did not happen.
This commit introduces a new function securityfs_recursive_remove
to recursively delete a directory without leaving an unclean state.
Co-developed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
IPE is designed to provide system level trust guarantees, this usually
implies that trust starts from bootup with a hardware root of trust,
which validates the bootloader. After this, the bootloader verifies
the kernel and the initramfs.
As there's no currently supported integrity method for initramfs, and
it's typically already verified by the bootloader. This patch introduces
a new IPE property `boot_verified` which allows author of IPE policy to
indicate trust for files from initramfs.
The implementation of this feature utilizes the newly added
`initramfs_populated` hook. This hook marks the superblock of the rootfs
after the initramfs has been unpacked into it.
Before mounting the real rootfs on top of the initramfs, initramfs
script will recursively remove all files and directories on the
initramfs. This is typically implemented by using switch_root(8)
(https://man7.org/linux/man-pages/man8/switch_root.8.html).
Therefore the initramfs will be empty and not accessible after the real
rootfs takes over. It is advised to switch to a different policy
that doesn't rely on the `boot_verified` property after this point.
This ensures that the trust policies remain relevant and effective
throughout the system's operation.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch introduces a new hook to notify security system that the
content of initramfs has been unpacked into the rootfs.
Upon receiving this notification, the security system can activate
a policy to allow only files that originated from the initramfs to
execute or load into kernel during the early stages of booting.
This approach is crucial for minimizing the attack surface by
ensuring that only trusted files from the initramfs are operational
in the critical boot phase.
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
IPE's initial goal is to control both execution and the loading of
kernel modules based on the system's definition of trust. It
accomplishes this by plugging into the security hooks for
bprm_check_security, file_mprotect, mmap_file, kernel_load_data,
and kernel_read_data.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Introduce a core evaluation function in IPE that will be triggered by
various security hooks (e.g., mmap, bprm_check, kexec). This function
systematically assesses actions against the defined IPE policy, by
iterating over rules specific to the action being taken. This critical
addition enables IPE to enforce its security policies effectively,
ensuring that actions intercepted by these hooks are scrutinized for policy
compliance before they are allowed to proceed.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Reviewed-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
IPE's interpretation of the what the user trusts is accomplished through
its policy. IPE's design is to not provide support for a single trust
provider, but to support multiple providers to enable the end-user to
choose the best one to seek their needs.
This requires the policy to be rather flexible and modular so that
integrity providers, like fs-verity, dm-verity, or some other system,
can plug into the policy with minimal code changes.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: added NULL check in parse_rule() as discussed]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Integrity Policy Enforcement (IPE) is an LSM that provides an
complimentary approach to Mandatory Access Control than existing LSMs
today.
Existing LSMs have centered around the concept of access to a resource
should be controlled by the current user's credentials. IPE's approach,
is that access to a resource should be controlled by the system's trust
of a current resource.
The basis of this approach is defining a global policy to specify which
resource can be trusted.
Signed-off-by: Deven Bowers <deven.desai@linux.microsoft.com>
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Trusted keys unseal the key blob on load, but keep the sealed payload in
the blob field so that every subsequent read (export) will simply
convert this field to hex and send it to userspace.
With DCP-based trusted keys, we decrypt the blob encryption key (BEK)
in the Kernel due hardware limitations and then decrypt the blob payload.
BEK decryption is done in-place which means that the trusted key blob
field is modified and it consequently holds the BEK in plain text.
Every subsequent read of that key thus send the plain text BEK instead
of the encrypted BEK to userspace.
This issue only occurs when importing a trusted DCP-based key and
then exporting it again. This should rarely happen as the common use cases
are to either create a new trusted key and export it, or import a key
blob and then just use it without exporting it again.
Fix this by performing BEK decryption and encryption in a dedicated
buffer. Further always wipe the plain text BEK buffer to prevent leaking
the key via uninitialized memory.
Cc: stable@vger.kernel.org # v6.10+
Fixes: 2e8a0f40a3 ("KEYS: trusted: Introduce NXP DCP-backed trusted keys")
Signed-off-by: David Gstir <david@sigma-star.at>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The DCP trusted key type uses the wrong helper function to store
the blob's payload length which can lead to the wrong byte order
being used in case this would ever run on big endian architectures.
Fix by using correct helper function.
Cc: stable@vger.kernel.org # v6.10+
Fixes: 2e8a0f40a3 ("KEYS: trusted: Introduce NXP DCP-backed trusted keys")
Suggested-by: Richard Weinberger <richard@nod.at>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405240610.fj53EK0q-lkp@intel.com/
Signed-off-by: David Gstir <david@sigma-star.at>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Fix sparse warning:
security/lockdown/lockdown.c:79:21: warning:
symbol 'lockdown_lsmid' was not declared. Should it be static?
Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Kees Cook <kees@kernel.org>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The LSM framework has an existing inode_free_security() hook which
is used by LSMs that manage state associated with an inode, but
due to the use of RCU to protect the inode, special care must be
taken to ensure that the LSMs do not fully release the inode state
until it is safe from a RCU perspective.
This patch implements a new inode_free_security_rcu() implementation
hook which is called when it is safe to free the LSM's internal inode
state. Unfortunately, this new hook does not have access to the inode
itself as it may already be released, so the existing
inode_free_security() hook is retained for those LSMs which require
access to the inode.
Cc: stable@vger.kernel.org
Reported-by: syzbot+5446fbf332b0602ede0b@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/r/00000000000076ba3b0617f65cc8@google.com
Signed-off-by: Paul Moore <paul@paul-moore.com>
Some cleanup and style corrections for lsm_hooks.h.
* Drop the lsm_inode_alloc() extern declaration, it is not needed.
* Relocate lsm_get_xattr_slot() and extern variables in the file to
improve grouping of related objects.
* Don't use tabs to needlessly align structure fields.
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Unfortunately it appears that vma_is_initial_heap() is currently broken
for applications that do not currently have any heap allocated, e.g.
brk == start_brk. The breakage is such that it will cause SELinux to
check for the process/execheap permission on memory regions that cross
brk/start_brk even when there is no heap.
The proper fix would be to correct vma_is_initial_heap(), but as there
are multiple callers I am hesitant to unilaterally modify the helper
out of concern that I would end up breaking some other subsystem. The
mm developers have been made aware of the situation and hopefully they
will have a fix at some point in the future, but we need a fix soon so
we are simply going to revert our use of vma_is_initial_heap() in favor
of our old logic/code which works as expected, even in the face of a
zero size heap. We can return to using vma_is_initial_heap() at some
point in the future when it is fixed.
Cc: stable@vger.kernel.org
Reported-by: Marc Reisner <reisner.marc@gmail.com>
Closes: https://lore.kernel.org/all/ZrPmoLKJEf1wiFmM@marcreisner.com
Fixes: 68df1baf15 ("selinux: use vma_is_initial_stack() and vma_is_initial_heap()")
Signed-off-by: Paul Moore <paul@paul-moore.com>
When avc_add_xperms_decision() fails, the information recorded by the new
avc node is incomplete. In this case, the new avc node should be released
instead of replacing the old avc node.
Cc: stable@vger.kernel.org
Fixes: fa1aa143ac ("selinux: extended permissions for ioctls")
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The count increases only when a node is successfully added to
the linked list.
Cc: stable@vger.kernel.org
Fixes: fa1aa143ac ("selinux: extended permissions for ioctls")
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
To be consistent with most LSM hooks, convert the return value of
hook inode_copy_up_xattr to 0 or a negative error code.
Before:
- Hook inode_copy_up_xattr returns 0 when accepting xattr, 1 when
discarding xattr, -EOPNOTSUPP if it does not know xattr, or any
other negative error code otherwise.
After:
- Hook inode_copy_up_xattr returns 0 when accepting xattr, *-ECANCELED*
when discarding xattr, -EOPNOTSUPP if it does not know xattr, or
any other negative error code otherwise.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
To be consistent with most LSM hooks, convert the return value of
hook vm_enough_memory to 0 or a negative error code.
Before:
- Hook vm_enough_memory returns 1 if permission is granted, 0 if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 1.
After:
- Hook vm_enough_memory reutrns 0 if permission is granted, negative
error code if not.
- LSM_RET_DEFAULT(vm_enough_memory_mm) is 0.
Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move management of the perf_event->security blob out of the individual
security modules and into the security infrastructure. Instead of
allocating the blobs from within the modules the modules tell the
infrastructure how much space is required, and the space is allocated
there. There are no longer any modules that require the perf_event_free()
hook. The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move management of the infiniband security blob out of the individual
security modules and into the LSM infrastructure. The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the ib_free() hook.
The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Move management of the dev_tun security blob out of the individual
security modules and into the LSM infrastructure. The security modules
tell the infrastructure how much space they require at initialization.
There are no longer any modules that require the dev_tun_free hook.
The hook definition has been removed.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak, selinux style fixes]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Create a helper function lsm_blob_alloc() for general use in the hook
specific functions that allocate LSM blobs. Change the hook specific
functions to use this helper. This reduces the code size by a small
amount and will make adding new instances of infrastructure managed
security blobs easier.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Reviewed-by: John Johansen <john.johansen@canonical.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
