Pull kernel lockdown mode from James Morris:
"This is the latest iteration of the kernel lockdown patchset, from
Matthew Garrett, David Howells and others.
From the original description:
This patchset introduces an optional kernel lockdown feature,
intended to strengthen the boundary between UID 0 and the kernel.
When enabled, various pieces of kernel functionality are restricted.
Applications that rely on low-level access to either hardware or the
kernel may cease working as a result - therefore this should not be
enabled without appropriate evaluation beforehand.
The majority of mainstream distributions have been carrying variants
of this patchset for many years now, so there's value in providing a
doesn't meet every distribution requirement, but gets us much closer
to not requiring external patches.
There are two major changes since this was last proposed for mainline:
- Separating lockdown from EFI secure boot. Background discussion is
covered here: https://lwn.net/Articles/751061/
- Implementation as an LSM, with a default stackable lockdown LSM
module. This allows the lockdown feature to be policy-driven,
rather than encoding an implicit policy within the mechanism.
The new locked_down LSM hook is provided to allow LSMs to make a
policy decision around whether kernel functionality that would allow
tampering with or examining the runtime state of the kernel should be
permitted.
The included lockdown LSM provides an implementation with a simple
policy intended for general purpose use. This policy provides a coarse
level of granularity, controllable via the kernel command line:
lockdown={integrity|confidentiality}
Enable the kernel lockdown feature. If set to integrity, kernel features
that allow userland to modify the running kernel are disabled. If set to
confidentiality, kernel features that allow userland to extract
confidential information from the kernel are also disabled.
This may also be controlled via /sys/kernel/security/lockdown and
overriden by kernel configuration.
New or existing LSMs may implement finer-grained controls of the
lockdown features. Refer to the lockdown_reason documentation in
include/linux/security.h for details.
The lockdown feature has had signficant design feedback and review
across many subsystems. This code has been in linux-next for some
weeks, with a few fixes applied along the way.
Stephen Rothwell noted that commit 9d1f8be5cf ("bpf: Restrict bpf
when kernel lockdown is in confidentiality mode") is missing a
Signed-off-by from its author. Matthew responded that he is providing
this under category (c) of the DCO"
* 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (31 commits)
kexec: Fix file verification on S390
security: constify some arrays in lockdown LSM
lockdown: Print current->comm in restriction messages
efi: Restrict efivar_ssdt_load when the kernel is locked down
tracefs: Restrict tracefs when the kernel is locked down
debugfs: Restrict debugfs when the kernel is locked down
kexec: Allow kexec_file() with appropriate IMA policy when locked down
lockdown: Lock down perf when in confidentiality mode
bpf: Restrict bpf when kernel lockdown is in confidentiality mode
lockdown: Lock down tracing and perf kprobes when in confidentiality mode
lockdown: Lock down /proc/kcore
x86/mmiotrace: Lock down the testmmiotrace module
lockdown: Lock down module params that specify hardware parameters (eg. ioport)
lockdown: Lock down TIOCSSERIAL
lockdown: Prohibit PCMCIA CIS storage when the kernel is locked down
acpi: Disable ACPI table override if the kernel is locked down
acpi: Ignore acpi_rsdp kernel param when the kernel has been locked down
ACPI: Limit access to custom_method when the kernel is locked down
x86/msr: Restrict MSR access when the kernel is locked down
x86: Lock down IO port access when the kernel is locked down
...
Disallow opening of debugfs files that might be used to muck around when
the kernel is locked down as various drivers give raw access to hardware
through debugfs. Given the effort of auditing all 2000 or so files and
manually fixing each one as necessary, I've chosen to apply a heuristic
instead. The following changes are made:
(1) chmod and chown are disallowed on debugfs objects (though the root dir
can be modified by mount and remount, but I'm not worried about that).
(2) When the kernel is locked down, only files with the following criteria
are permitted to be opened:
- The file must have mode 00444
- The file must not have ioctl methods
- The file must not have mmap
(3) When the kernel is locked down, files may only be opened for reading.
Normal device interaction should be done through configfs, sysfs or a
miscdev, not debugfs.
Note that this makes it unnecessary to specifically lock down show_dsts(),
show_devs() and show_call() in the asus-wmi driver.
I would actually prefer to lock down all files by default and have the
the files unlocked by the creator. This is tricky to manage correctly,
though, as there are 19 creation functions and ~1600 call sites (some of
them in loops scanning tables).
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Andy Shevchenko <andy.shevchenko@gmail.com>
cc: acpi4asus-user@lists.sourceforge.net
cc: platform-driver-x86@vger.kernel.org
cc: Matthew Garrett <mjg59@srcf.ucam.org>
cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg KH <greg@kroah.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Signed-off-by: Matthew Garrett <matthewgarrett@google.com>
Signed-off-by: James Morris <jmorris@namei.org>
Pull driver core and debugfs updates from Greg KH:
"Here is the "big" driver core and debugfs changes for 5.3-rc1
It's a lot of different patches, all across the tree due to some api
changes and lots of debugfs cleanups.
Other than the debugfs cleanups, in this set of changes we have:
- bus iteration function cleanups
- scripts/get_abi.pl tool to display and parse Documentation/ABI
entries in a simple way
- cleanups to Documenatation/ABI/ entries to make them parse easier
due to typos and other minor things
- default_attrs use for some ktype users
- driver model documentation file conversions to .rst
- compressed firmware file loading
- deferred probe fixes
All of these have been in linux-next for a while, with a bunch of
merge issues that Stephen has been patient with me for"
* tag 'driver-core-5.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (102 commits)
debugfs: make error message a bit more verbose
orangefs: fix build warning from debugfs cleanup patch
ubifs: fix build warning after debugfs cleanup patch
driver: core: Allow subsystems to continue deferring probe
drivers: base: cacheinfo: Ensure cpu hotplug work is done before Intel RDT
arch_topology: Remove error messages on out-of-memory conditions
lib: notifier-error-inject: no need to check return value of debugfs_create functions
swiotlb: no need to check return value of debugfs_create functions
ceph: no need to check return value of debugfs_create functions
sunrpc: no need to check return value of debugfs_create functions
ubifs: no need to check return value of debugfs_create functions
orangefs: no need to check return value of debugfs_create functions
nfsd: no need to check return value of debugfs_create functions
lib: 842: no need to check return value of debugfs_create functions
debugfs: provide pr_fmt() macro
debugfs: log errors when something goes wrong
drivers: s390/cio: Fix compilation warning about const qualifiers
drivers: Add generic helper to match by of_node
driver_find_device: Unify the match function with class_find_device()
bus_find_device: Unify the match callback with class_find_device
...
Move simple_unlink()+d_delete() from __debugfs_remove_file() into
caller __debugfs_remove() and rename helper for post remove file to
__debugfs_file_removed().
This will simplify adding fsnotify_unlink() hook.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
The single user of debugfs_create_u32_array() does not care about the
return value of it, so make it return void as there is no need to do
anything with the return value.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull misc dcache updates from Al Viro:
"Most of this pile is putting name length into struct name_snapshot and
making use of it.
The beginning of this series ("ovl_lookup_real_one(): don't bother
with strlen()") ought to have been split in two (separate switch of
name_snapshot to struct qstr from overlayfs reaping the trivial
benefits of that), but I wanted to avoid a rebase - by the time I'd
spotted that it was (a) in -next and (b) close to 5.1-final ;-/"
* 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
audit_compare_dname_path(): switch to const struct qstr *
audit_update_watch(): switch to const struct qstr *
inotify_handle_event(): don't bother with strlen()
fsnotify: switch send_to_group() and ->handle_event to const struct qstr *
fsnotify(): switch to passing const struct qstr * for file_name
switch fsnotify_move() to passing const struct qstr * for old_name
ovl_lookup_real_one(): don't bother with strlen()
sysv: bury the broken "quietly truncate the long filenames" logics
nsfs: unobfuscate
unexport d_alloc_pseudo()
Pull driver core/kobject updates from Greg KH:
"Here is the "big" set of driver core patches for 5.2-rc1
There are a number of ACPI patches in here as well, as Rafael said
they should go through this tree due to the driver core changes they
required. They have all been acked by the ACPI developers.
There are also a number of small subsystem-specific changes in here,
due to some changes to the kobject core code. Those too have all been
acked by the various subsystem maintainers.
As for content, it's pretty boring outside of the ACPI changes:
- spdx cleanups
- kobject documentation updates
- default attribute groups for kobjects
- other minor kobject/driver core fixes
All have been in linux-next for a while with no reported issues"
* tag 'driver-core-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (47 commits)
kobject: clean up the kobject add documentation a bit more
kobject: Fix kernel-doc comment first line
kobject: Remove docstring reference to kset
firmware_loader: Fix a typo ("syfs" -> "sysfs")
kobject: fix dereference before null check on kobj
Revert "driver core: platform: Fix the usage of platform device name(pdev->name)"
init/config: Do not select BUILD_BIN2C for IKCONFIG
Provide in-kernel headers to make extending kernel easier
kobject: Improve doc clarity kobject_init_and_add()
kobject: Improve docs for kobject_add/del
driver core: platform: Fix the usage of platform device name(pdev->name)
livepatch: Replace klp_ktype_patch's default_attrs with groups
cpufreq: schedutil: Replace default_attrs field with groups
padata: Replace padata_attr_type default_attrs field with groups
irqdesc: Replace irq_kobj_type's default_attrs field with groups
net-sysfs: Replace ktype default_attrs field with groups
block: Replace all ktype default_attrs with groups
samples/kobject: Replace foo_ktype's default_attrs field with groups
kobject: Add support for default attribute groups to kobj_type
driver core: Postpone DMA tear-down until after devres release for probe failure
...
note that in the second (RENAME_EXCHANGE) call of fsnotify_move() in
vfs_rename() the old_dentry->d_name is guaranteed to be unchanged
throughout the evaluation of fsnotify_move() (by the fact that the
parent directory is locked exclusive), so we don't need to fetch
old_dentry->d_name.name in the caller.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Since commit ff9fb72bc0 ("debugfs: return error values, not NULL")
these helper functions do not return NULL anymore (with the exception
of debugfs_create_u32_array()).
Fixes: ff9fb72bc0 ("debugfs: return error values, not NULL")
Signed-off-by: Ronald Tschalär <ronald@innovation.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
symlink body shouldn't be freed without an RCU delay. Switch debugfs to
->destroy_inode() and use of call_rcu(); free both the inode and symlink
body in the callback. Similar to solution for bpf, only here it's even
more obvious that ->evict_inode() can be dropped.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When an error happens, debugfs should return an error pointer value, not
NULL. This will prevent the totally theoretical error where a debugfs
call fails due to lack of memory, returning NULL, and that dentry value
is then passed to another debugfs call, which would end up succeeding,
creating a file at the root of the debugfs tree, but would then be
impossible to remove (because you can not remove the directory NULL).
So, to make everyone happy, always return errors, this makes the users
of debugfs much simpler (they do not have to ever check the return
value), and everyone can rest easy.
Reported-by: Gary R Hook <ghook@amd.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Reported-by: Michal Hocko <mhocko@kernel.org>
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
debugfs_rename() needs to check that the dentries passed into it really
are valid, as sometimes they are not (i.e. if the return value of
another debugfs call is passed into this one.) So fix this up by
properly checking if the two parent directories are errors (they are
allowed to be NULL), and if the dentry to rename is not NULL or an
error.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
debugfs_use_file_start() and debugfs_use_file_finish() do not exist
since commit c9afbec270 ("debugfs: purge obsolete SRCU based removal
protection"); tweak debugfs_create_file_unsafe() comment.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 95cde3c599.
The commit had good intentions, but it breaks kvm-tool and qemu-kvm.
With it in place, "lkvm run" just fails with
Error: KVM_CREATE_VM ioctl
Warning: Failed init: kvm__init
which isn't a wonderful error message, but bisection pinpointed the
problematic commit.
The problem is almost certainly due to the special kvm debugfs entries
created dynamically by kvm under /sys/kernel/debug/kvm/. See
kvm_create_vm_debugfs()
Bisected-and-reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Wanpeng Li <kernellwp@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
