The lockdown LSM is primarily used in conjunction with UEFI Secure Boot.
This LSM may also be used on machines without UEFI. It can also be
enabled when UEFI Secure Boot is disabled. One of lockdown's features
is to prevent kexec from loading untrusted kernels. Lockdown can be
enabled through a bootparam or after the kernel has booted through
securityfs.
If IMA appraisal is used with the "ima_appraise=log" boot param,
lockdown can be defeated with kexec on any machine when Secure Boot is
disabled or unavailable. IMA prevents setting "ima_appraise=log" from
the boot param when Secure Boot is enabled, but this does not cover
cases where lockdown is used without Secure Boot.
To defeat lockdown, boot without Secure Boot and add ima_appraise=log to
the kernel command line; then:
$ echo "integrity" > /sys/kernel/security/lockdown
$ echo "appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig" > \
/sys/kernel/security/ima/policy
$ kexec -ls unsigned-kernel
Add a call to verify ima appraisal is set to "enforce" whenever lockdown
is enabled. This fixes CVE-2022-21505.
Cc: stable@vger.kernel.org
Fixes: 29d3c1c8df ("kexec: Allow kexec_file() with appropriate IMA policy when locked down")
Signed-off-by: Eric Snowberg <eric.snowberg@oracle.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Reviewed-by: John Haxby <john.haxby@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'integrity-v5.19-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity fixes from Mimi Zohar:
"Here are a number of fixes for recently found bugs.
Only 'ima: fix violation measurement list record' was introduced in
the current release. The rest address existing bugs"
* tag 'integrity-v5.19-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
ima: Fix potential memory leak in ima_init_crypto()
ima: force signature verification when CONFIG_KEXEC_SIG is configured
ima: Fix a potential integer overflow in ima_appraise_measurement
ima: fix violation measurement list record
Revert "evm: Fix memleak in init_desc"
On failure to allocate the SHA1 tfm, IMA fails to initialize and exits
without freeing the ima_algo_array. Add the missing kfree() for
ima_algo_array to avoid the potential memory leak.
Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
Fixes: 6d94809af6 ("ima: Allocate and initialize tfm for each PCR bank")
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Currently, an unsigned kernel could be kexec'ed when IMA arch specific
policy is configured unless lockdown is enabled. Enforce kernel
signature verification check in the kexec_file_load syscall when IMA
arch specific policy is configured.
Fixes: 99d5cadfde ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE")
Reported-and-suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
When the ima-modsig is enabled, the rc passed to evm_verifyxattr() may be
negative, which may cause the integer overflow problem.
Fixes: 39b0709636 ("ima: Implement support for module-style appended signatures")
Signed-off-by: Huaxin Lu <luhuaxin1@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Although the violation digest in the IMA measurement list is always
zeroes, the size of the digest should be based on the hash algorithm.
Until recently the hash algorithm was hard coded to sha1. Fix the
violation digest size included in the IMA measurement list.
This is just a cosmetic change which should not affect attestation.
Reported-by: Stefan Berger <stefanb@linux.ibm.com>
Fixes: 09091c44cb ("ima: use IMA default hash algorithm for integrity violations")
Tested-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Do fine-grained Kconfig for all the various retbleed parts.
NOTE: if your compiler doesn't support return thunks this will
silently 'upgrade' your mitigation to IBPB, you might not like this.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
This reverts commit ccf11dbaa0.
Commit ccf11dbaa0 ("evm: Fix memleak in init_desc") said there is
memleak in init_desc. That may be incorrect, as we can see, tmp_tfm is
saved in one of the two global variables hmac_tfm or evm_tfm[hash_algo],
then if init_desc is called next time, there is no need to alloc tfm
again, so in the error path of kmalloc desc or crypto_shash_init(desc),
It is not a problem without freeing tmp_tfm.
And also that commit did not reset the global variable to NULL after
freeing tmp_tfm and this makes *tfm a dangling pointer which may cause a
UAF issue.
Reported-by: Guozihua (Scott) <guozihua@huawei.com>
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
When creating (sealing) a new trusted key, migratable
trusted keys have the FIXED_TPM and FIXED_PARENT attributes
set, and non-migratable keys don't. This is backwards, and
also causes creation to fail when creating a migratable key
under a migratable parent. (The TPM thinks you are trying to
seal a non-migratable blob under a migratable parent.)
The following simple patch fixes the logic, and has been
tested for all four combinations of migratable and non-migratable
trusted keys and parent storage keys. With this logic, you will
get a proper failure if you try to create a non-migratable
trusted key under a migratable parent storage key, and all other
combinations work correctly.
Cc: stable@vger.kernel.org # v5.13+
Fixes: e5fb5d2c5a ("security: keys: trusted: Make sealed key properly interoperable")
Signed-off-by: David Safford <david.safford@gmail.com>
Reviewed-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The fix is usermode_driver.c one - once you've done kern_mount(), you
must kern_unmount(); simple mntput() will end up with a leak. Several
failure exits in there messed up that way... In practice you won't
hit those particular failure exits without fault injection, though.
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Merge tag 'pull-18-rc1-work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull mount handling updates from Al Viro:
"Cleanups (and one fix) around struct mount handling.
The fix is usermode_driver.c one - once you've done kern_mount(), you
must kern_unmount(); simple mntput() will end up with a leak. Several
failure exits in there messed up that way... In practice you won't hit
those particular failure exits without fault injection, though"
* tag 'pull-18-rc1-work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
move mount-related externs from fs.h to mount.h
blob_to_mnt(): kern_unmount() is needed to undo kern_mount()
m->mnt_root->d_inode->i_sb is a weird way to spell m->mnt_sb...
linux/mount.h: trim includes
uninline may_mount() and don't opencode it in fspick(2)/fsopen(2)
This KUnit update for Linux 5.19-rc1 consists of several fixes, cleanups,
and enhancements to tests and framework:
- introduces _NULL and _NOT_NULL macros to pointer error checks
- reworks kunit_resource allocation policy to fix memory leaks when
caller doesn't specify free() function to be used when allocating
memory using kunit_add_resource() and kunit_alloc_resource() funcs.
- adds ability to specify suite-level init and exit functions
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Merge tag 'linux-kselftest-kunit-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest
Pull KUnit updates from Shuah Khan:
"Several fixes, cleanups, and enhancements to tests and framework:
- introduce _NULL and _NOT_NULL macros to pointer error checks
- rework kunit_resource allocation policy to fix memory leaks when
caller doesn't specify free() function to be used when allocating
memory using kunit_add_resource() and kunit_alloc_resource() funcs.
- add ability to specify suite-level init and exit functions"
* tag 'linux-kselftest-kunit-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (41 commits)
kunit: tool: Use qemu-system-i386 for i386 runs
kunit: fix executor OOM error handling logic on non-UML
kunit: tool: update riscv QEMU config with new serial dependency
kcsan: test: use new suite_{init,exit} support
kunit: tool: Add list of all valid test configs on UML
kunit: take `kunit_assert` as `const`
kunit: tool: misc cleanups
kunit: tool: minor cosmetic cleanups in kunit_parser.py
kunit: tool: make parser stop overwriting status of suites w/ no_tests
kunit: tool: remove dead parse_crash_in_log() logic
kunit: tool: print clearer error message when there's no TAP output
kunit: tool: stop using a shell to run kernel under QEMU
kunit: tool: update test counts summary line format
kunit: bail out of test filtering logic quicker if OOM
lib/Kconfig.debug: change KUnit tests to default to KUNIT_ALL_TESTS
kunit: Rework kunit_resource allocation policy
kunit: fix debugfs code to use enum kunit_status, not bool
kfence: test: use new suite_{init/exit} support, add .kunitconfig
kunit: add ability to specify suite-level init and exit functions
kunit: rename print_subtest_{start,end} for clarity (s/subtest/suite)
...
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Merge tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull IMA updates from Mimi Zohar:
"New is IMA support for including fs-verity file digests and signatures
in the IMA measurement list as well as verifying the fs-verity file
digest based signatures, both based on policy.
In addition, are two bug fixes:
- avoid reading UEFI variables, which cause a page fault, on Apple
Macs with T2 chips.
- remove the original "ima" template Kconfig option to address a boot
command line ordering issue.
The rest is a mixture of code/documentation cleanup"
* tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
integrity: Fix sparse warnings in keyring_handler
evm: Clean up some variables
evm: Return INTEGRITY_PASS for enum integrity_status value '0'
efi: Do not import certificates from UEFI Secure Boot for T2 Macs
fsverity: update the documentation
ima: support fs-verity file digest based version 3 signatures
ima: permit fsverity's file digests in the IMA measurement list
ima: define a new template field named 'd-ngv2' and templates
fs-verity: define a function to return the integrity protected file digest
ima: use IMA default hash algorithm for integrity violations
ima: fix 'd-ng' comments and documentation
ima: remove the IMA_TEMPLATE Kconfig option
ima: remove redundant initialization of pointer 'file'.
- Strictened validation of key hashes for SYSTEM_BLACKLIST_HASH_LIST. An
invalid hash format causes a compilation error. Previously, they got
included to the kernel binary but were silently ignored at run-time.
- Allow root user to append new hashes to the blacklist keyring.
- Trusted keys backed with Cryptographic Acceleration and Assurance Module
(CAAM), which part of some of the new NXP's SoC's. Now there is total
three hardware backends for trusted keys: TPM, ARM TEE and CAAM.
- A scattered set of fixes and small improvements for the TPM driver.
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
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Merge tag 'tpmdd-next-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd
Pull tpm updates from Jarkko Sakkinen:
- Tightened validation of key hashes for SYSTEM_BLACKLIST_HASH_LIST. An
invalid hash format causes a compilation error. Previously, they got
included to the kernel binary but were silently ignored at run-time.
- Allow root user to append new hashes to the blacklist keyring.
- Trusted keys backed with Cryptographic Acceleration and Assurance
Module (CAAM), which part of some of the new NXP's SoC's. Now there
is total three hardware backends for trusted keys: TPM, ARM TEE and
CAAM.
- A scattered set of fixes and small improvements for the TPM driver.
* tag 'tpmdd-next-v5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jarkko/linux-tpmdd:
MAINTAINERS: add KEYS-TRUSTED-CAAM
doc: trusted-encrypted: describe new CAAM trust source
KEYS: trusted: Introduce support for NXP CAAM-based trusted keys
crypto: caam - add in-kernel interface for blob generator
crypto: caam - determine whether CAAM supports blob encap/decap
KEYS: trusted: allow use of kernel RNG for key material
KEYS: trusted: allow use of TEE as backend without TCG_TPM support
tpm: Add field upgrade mode support for Infineon TPM2 modules
tpm: Fix buffer access in tpm2_get_tpm_pt()
char: tpm: cr50_i2c: Suppress duplicated error message in .remove()
tpm: cr50: Add new device/vendor ID 0x504a6666
tpm: Remove read16/read32/write32 calls from tpm_tis_phy_ops
tpm: ibmvtpm: Correct the return value in tpm_ibmvtpm_probe()
tpm/tpm_ftpm_tee: Return true/false (not 1/0) from bool functions
certs: Explain the rationale to call panic()
certs: Allow root user to append signed hashes to the blacklist keyring
certs: Check that builtin blacklist hashes are valid
certs: Make blacklist_vet_description() more strict
certs: Factor out the blacklist hash creation
tools/certs: Add print-cert-tbs-hash.sh
Important changes:
* improve the path_rename LSM hook implementations for RENAME_EXCHANGE;
* fix a too-restrictive filesystem control for a rare corner case;
* set the nested sandbox limitation to 16 layers;
* add a new LANDLOCK_ACCESS_FS_REFER access right to properly handle
file reparenting (i.e. full rename and link support);
* add new tests and documentation;
* format code with clang-format to make it easier to maintain and
contribute.
Related patch series:
* [PATCH v1 0/7] Landlock: Clean up coding style with clang-format
https://lore.kernel.org/r/20220506160513.523257-1-mic@digikod.net
* [PATCH v2 00/10] Minor Landlock fixes and new tests
https://lore.kernel.org/r/20220506160820.524344-1-mic@digikod.net
* [PATCH v3 00/12] Landlock: file linking and renaming support
https://lore.kernel.org/r/20220506161102.525323-1-mic@digikod.net
* [PATCH v2] landlock: Explain how to support Landlock
https://lore.kernel.org/r/20220513112743.156414-1-mic@digikod.net
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Merge tag 'landlock-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux
Pull Landlock updates from Mickaël Salaün:
- improve the path_rename LSM hook implementations for RENAME_EXCHANGE;
- fix a too-restrictive filesystem control for a rare corner case;
- set the nested sandbox limitation to 16 layers;
- add a new LANDLOCK_ACCESS_FS_REFER access right to properly handle
file reparenting (i.e. full rename and link support);
- add new tests and documentation;
- format code with clang-format to make it easier to maintain and
contribute.
* tag 'landlock-5.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/mic/linux: (30 commits)
landlock: Explain how to support Landlock
landlock: Add design choices documentation for filesystem access rights
landlock: Document good practices about filesystem policies
landlock: Document LANDLOCK_ACCESS_FS_REFER and ABI versioning
samples/landlock: Add support for file reparenting
selftests/landlock: Add 11 new test suites dedicated to file reparenting
landlock: Add support for file reparenting with LANDLOCK_ACCESS_FS_REFER
LSM: Remove double path_rename hook calls for RENAME_EXCHANGE
landlock: Move filesystem helpers and add a new one
landlock: Fix same-layer rule unions
landlock: Create find_rule() from unmask_layers()
landlock: Reduce the maximum number of layers to 16
landlock: Define access_mask_t to enforce a consistent access mask size
selftests/landlock: Test landlock_create_ruleset(2) argument check ordering
landlock: Change landlock_restrict_self(2) check ordering
landlock: Change landlock_add_rule(2) argument check ordering
selftests/landlock: Add tests for O_PATH
selftests/landlock: Fully test file rename with "remove" access
selftests/landlock: Extend access right tests to directories
selftests/landlock: Add tests for unknown access rights
...
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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
KGDB and KDB allow read and write access to kernel memory, and thus
should be restricted during lockdown. An attacker with access to a
serial port (for example, via a hypervisor console, which some cloud
vendors provide over the network) could trigger the debugger so it is
important that the debugger respect the lockdown mode when/if it is
triggered.
Fix this by integrating lockdown into kdb's existing permissions
mechanism. Unfortunately kgdb does not have any permissions mechanism
(although it certainly could be added later) so, for now, kgdb is simply
and brutally disabled by immediately exiting the gdb stub without taking
any action.
For lockdowns established early in the boot (e.g. the normal case) then
this should be fine but on systems where kgdb has set breakpoints before
the lockdown is enacted than "bad things" will happen.
CVE: CVE-2022-21499
Co-developed-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Get rid of redundant assignments which end up in values not being
read either because they are overwritten or the function ends.
Reported by clang-tidy [deadcode.DeadStores]
Signed-off-by: Michal Orzel <michalorzel.eng@gmail.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
The Cryptographic Acceleration and Assurance Module (CAAM) is an IP core
built into many newer i.MX and QorIQ SoCs by NXP.
The CAAM does crypto acceleration, hardware number generation and
has a blob mechanism for encapsulation/decapsulation of sensitive material.
This blob mechanism depends on a device specific random 256-bit One Time
Programmable Master Key that is fused in each SoC at manufacturing
time. This key is unreadable and can only be used by the CAAM for AES
encryption/decryption of user data.
This makes it a suitable backend (source) for kernel trusted keys.
Previous commits generalized trusted keys to support multiple backends
and added an API to access the CAAM blob mechanism. Based on these,
provide the necessary glue to use the CAAM for trusted keys.
Reviewed-by: David Gstir <david@sigma-star.at>
Reviewed-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Tim Harvey <tharvey@gateworks.com>
Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Tested-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Tested-by: Michael Walle <michael@walle.cc> # on ls1028a (non-E and E)
Tested-by: John Ernberg <john.ernberg@actia.se> # iMX8QXP
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
The two existing trusted key sources don't make use of the kernel RNG,
but instead let the hardware doing the sealing/unsealing also
generate the random key material. However, both users and future
backends may want to place less trust into the quality of the trust
source's random number generator and instead reuse the kernel entropy
pool, which can be seeded from multiple entropy sources.
Make this possible by adding a new trusted.rng parameter,
that will force use of the kernel RNG. In its absence, it's up
to the trust source to decide, which random numbers to use,
maintaining the existing behavior.
Suggested-by: Jarkko Sakkinen <jarkko@kernel.org>
Acked-by: Sumit Garg <sumit.garg@linaro.org>
Acked-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Reviewed-by: David Gstir <david@sigma-star.at>
Reviewed-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Tested-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Tested-by: Michael Walle <michael@walle.cc> # on ls1028a (non-E and E)
Tested-by: John Ernberg <john.ernberg@actia.se> # iMX8QXP
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
With recent rework, trusted keys are no longer limited to TPM as trust
source. The Kconfig symbol is unchanged however leading to a few issues:
- TCG_TPM is required, even if only TEE is to be used
- Enabling TCG_TPM, but excluding it from available trusted sources
is not possible
- TEE=m && TRUSTED_KEYS=y will lead to TEE support being silently
dropped, which is not the best user experience
Remedy these issues by introducing two new boolean Kconfig symbols:
TRUSTED_KEYS_TPM and TRUSTED_KEYS_TEE with the appropriate
dependencies.
Any new code depending on the TPM trusted key backend in particular
or symbols exported by it will now need to explicitly state that it
depends on TRUSTED_KEYS && TRUSTED_KEYS_TPM
The latter to ensure the dependency is built and the former to ensure
it's reachable for module builds. There are no such users yet.
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Tested-by: Pankaj Gupta <pankaj.gupta@nxp.com>
Tested-by: Andreas Rammhold <andreas@rammhold.de>
Tested-by: Tim Harvey <tharvey@gateworks.com>
Tested-by: Michael Walle <michael@walle.cc> # on ls1028a (non-E and E)
Tested-by: John Ernberg <john.ernberg@actia.se> # iMX8QXP
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Factor out the blacklist hash creation with the get_raw_hash() helper.
This also centralize the "tbs" and "bin" prefixes and make them private,
which help to manage them consistently.
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Eric Snowberg <eric.snowberg@oracle.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com>
Link: https://lore.kernel.org/r/20210712170313.884724-5-mic@digikod.net
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
Add a new LANDLOCK_ACCESS_FS_REFER access right to enable policy writers
to allow sandboxed processes to link and rename files from and to a
specific set of file hierarchies. This access right should be composed
with LANDLOCK_ACCESS_FS_MAKE_* for the destination of a link or rename,
and with LANDLOCK_ACCESS_FS_REMOVE_* for a source of a rename. This
lift a Landlock limitation that always denied changing the parent of an
inode.
Renaming or linking to the same directory is still always allowed,
whatever LANDLOCK_ACCESS_FS_REFER is used or not, because it is not
considered a threat to user data.
However, creating multiple links or renaming to a different parent
directory may lead to privilege escalations if not handled properly.
Indeed, we must be sure that the source doesn't gain more privileges by
being accessible from the destination. This is handled by making sure
that the source hierarchy (including the referenced file or directory
itself) restricts at least as much the destination hierarchy. If it is
not the case, an EXDEV error is returned, making it potentially possible
for user space to copy the file hierarchy instead of moving or linking
it.
Instead of creating different access rights for the source and the
destination, we choose to make it simple and consistent for users.
Indeed, considering the previous constraint, it would be weird to
require such destination access right to be also granted to the source
(to make it a superset). Moreover, RENAME_EXCHANGE would also add to
the confusion because of paths being both a source and a destination.
See the provided documentation for additional details.
New tests are provided with a following commit.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-8-mic@digikod.net
In order to be able to identify a file exchange with renameat2(2) and
RENAME_EXCHANGE, which will be useful for Landlock [1], propagate the
rename flags to LSMs. This may also improve performance because of the
switch from two set of LSM hook calls to only one, and because LSMs
using this hook may optimize the double check (e.g. only one lock,
reduce the number of path walks).
AppArmor, Landlock and Tomoyo are updated to leverage this change. This
should not change the current behavior (same check order), except
(different level of) speed boosts.
[1] https://lore.kernel.org/r/20220221212522.320243-1-mic@digikod.net
Cc: James Morris <jmorris@namei.org>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Serge E. Hallyn <serge@hallyn.com>
Acked-by: John Johansen <john.johansen@canonical.com>
Acked-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-7-mic@digikod.net
Move the SB_NOUSER and IS_PRIVATE dentry check to a standalone
is_nouser_or_private() helper. This will be useful for a following
commit.
Move get_mode_access() and maybe_remove() to make them usable by new
code provided by a following commit.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Link: https://lore.kernel.org/r/20220506161102.525323-6-mic@digikod.net
The original behavior was to check if the full set of requested accesses
was allowed by at least a rule of every relevant layer. This didn't
take into account requests for multiple accesses and same-layer rules
allowing the union of these accesses in a complementary way. As a
result, multiple accesses requested on a file hierarchy matching rules
that, together, allowed these accesses, but without a unique rule
allowing all of them, was illegitimately denied. This case should be
rare in practice and it can only be triggered by the path_rename or
file_open hook implementations.
For instance, if, for the same layer, a rule allows execution
beneath /a/b and another rule allows read beneath /a, requesting access
to read and execute at the same time for /a/b should be allowed for this
layer.
This was an inconsistency because the union of same-layer rule accesses
was already allowed if requested once at a time anyway.
This fix changes the way allowed accesses are gathered over a path walk.
To take into account all these rule accesses, we store in a matrix all
layer granting the set of requested accesses, according to the handled
accesses. To avoid heap allocation, we use an array on the stack which
is 2*13 bytes. A following commit bringing the LANDLOCK_ACCESS_FS_REFER
access right will increase this size to reach 112 bytes (2*14*4) in case
of link or rename actions.
Add a new layout1.layer_rule_unions test to check that accesses from
different rules pertaining to the same layer are ORed in a file
hierarchy. Also test that it is not the case for rules from different
layers.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220506161102.525323-5-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
The maximum number of nested Landlock domains is currently 64. Because
of the following fix and to help reduce the stack size, let's reduce it
to 16. This seems large enough for a lot of use cases (e.g. sandboxed
init service, spawning a sandboxed SSH service, in nested sandboxed
containers). Reducing the number of nested domains may also help to
discover misuse of Landlock (e.g. creating a domain per rule).
Add and use a dedicated layer_mask_t typedef to fit with the number of
layers. This might be useful when changing it and to keep it consistent
with the maximum number of layers.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220506161102.525323-3-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
Create and use the access_mask_t typedef to enforce a consistent access
mask size and uniformly use a 16-bits type. This will helps transition
to a 32-bits value one day.
Add a build check to make sure all (filesystem) access rights fit in.
This will be extended with a following commit.
Reviewed-by: Paul Moore <paul@paul-moore.com>
Link: https://lore.kernel.org/r/20220506161102.525323-2-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
According to the Landlock goal to be a security feature available to
unprivileges processes, it makes more sense to first check for
no_new_privs before checking anything else (i.e. syscall arguments).
Merge inval_fd_enforce and unpriv_enforce_without_no_new_privs tests
into the new restrict_self_checks_ordering. This is similar to the
previous commit checking other syscalls.
Link: https://lore.kernel.org/r/20220506160820.524344-10-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
This makes more sense to first check the ruleset FD and then the rule
attribute. It will be useful to factor out code for other rule types.
Add inval_add_rule_arguments tests, extension of empty_path_beneath_attr
tests, to also check error ordering for landlock_add_rule(2).
Link: https://lore.kernel.org/r/20220506160820.524344-9-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
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>
The randstruct GCC plugin gets upset when it sees struct path (which is
randomized) being assigned from a "void *" (which it cannot type-check).
There's no need for these casts, as the entire internal payload use is
following a normal struct layout. Convert the enum-based void * offset
dereferencing to the new big_key_payload struct. No meaningful machine
code changes result after this change, and source readability is improved.
Drop the randstruct exception now that there is no "confusing" cross-type
assignment.
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Biggers <ebiggers@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-hardening@vger.kernel.org
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Fix the following sparse warnings:
CHECK security/integrity/platform_certs/keyring_handler.c
security/integrity/platform_certs/keyring_handler.c:76:16: warning: Using plain integer as NULL pointer
security/integrity/platform_certs/keyring_handler.c:91:16: warning: Using plain integer as NULL pointer
security/integrity/platform_certs/keyring_handler.c:106:16: warning: Using plain integer as NULL pointer
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Make hmac_tfm static since it's not used anywhere else besides the file
it is in.
Remove declaration of hash_tfm since it doesn't exist.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Return INTEGRITY_PASS for the enum integrity_status rather than 0.
Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables
at early boot to load UEFI Secure Boot certificates, a page fault occurs
in Apple firmware code and EFI runtime services are disabled with the
following logs:
[Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000
WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0
(Removed some logs from here)
Call Trace:
<TASK>
page_fault_oops+0x4f/0x2c0
? search_bpf_extables+0x6b/0x80
? search_module_extables+0x50/0x80
? search_exception_tables+0x5b/0x60
kernelmode_fixup_or_oops+0x9e/0x110
__bad_area_nosemaphore+0x155/0x190
bad_area_nosemaphore+0x16/0x20
do_kern_addr_fault+0x8c/0xa0
exc_page_fault+0xd8/0x180
asm_exc_page_fault+0x1e/0x30
(Removed some logs from here)
? __efi_call+0x28/0x30
? switch_mm+0x20/0x30
? efi_call_rts+0x19a/0x8e0
? process_one_work+0x222/0x3f0
? worker_thread+0x4a/0x3d0
? kthread+0x17a/0x1a0
? process_one_work+0x3f0/0x3f0
? set_kthread_struct+0x40/0x40
? ret_from_fork+0x22/0x30
</TASK>
---[ end trace 1f82023595a5927f ]---
efi: Froze efi_rts_wq and disabled EFI Runtime Services
integrity: Couldn't get size: 0x8000000000000015
integrity: MODSIGN: Couldn't get UEFI db list
efi: EFI Runtime Services are disabled!
integrity: Couldn't get size: 0x8000000000000015
integrity: Couldn't get UEFI dbx list
integrity: Couldn't get size: 0x8000000000000015
integrity: Couldn't get mokx list
integrity: Couldn't get size: 0x80000000
So we avoid reading these UEFI variables and thus prevent the crash.
Cc: stable@vger.kernel.org
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
The struct security_hook_list member lsm is assigned in
security_add_hooks() with string literals passed from the individual
security modules. Declare the function parameter and the struct member
const to signal their immutability.
Reported by Clang [-Wwrite-strings]:
security/selinux/hooks.c:7388:63: error: passing 'const char [8]'
to parameter of type 'char *' discards qualifiers
[-Werror,-Wincompatible-pointer-types-discards-qualifiers]
security_add_hooks(selinux_hooks,
ARRAY_SIZE(selinux_hooks), selinux);
^~~~~~~~~
./include/linux/lsm_hooks.h:1629:11: note: passing argument to
parameter 'lsm' here
char *lsm);
^
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Reviewed-by: Paul Moore <paul@paul-moore.com>
Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Let's follow a consistent and documented coding style. Everything may
not be to our liking but it is better than tacit knowledge. Moreover,
this will help maintain style consistency between different developers.
This contains only whitespace changes.
Automatically formatted with:
clang-format-14 -i security/landlock/*.[ch] include/uapi/linux/landlock.h
Link: https://lore.kernel.org/r/20220506160513.523257-3-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
In preparation to a following commit, add clang-format on and
clang-format off stanzas around constant definitions. This enables to
keep aligned values, which is much more readable than packed
definitions.
Link: https://lore.kernel.org/r/20220506160513.523257-2-mic@digikod.net
Cc: stable@vger.kernel.org
Signed-off-by: Mickaël Salaün <mic@digikod.net>
To enable Clang randstruct support, move the structure layout
randomization seed generation out of scripts/gcc-plugins/ into
scripts/basic/ so it happens early enough that it can be used by either
compiler implementation. The gcc-plugin still builds its own header file,
but now does so from the common "randstruct.seed" file.
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-6-keescook@chromium.org
In preparation for Clang supporting randstruct, reorganize the Kconfigs,
move the attribute macros, and generalize the feature to be named
CONFIG_RANDSTRUCT for on/off, CONFIG_RANDSTRUCT_FULL for the full
randomization mode, and CONFIG_RANDSTRUCT_PERFORMANCE for the cache-line
sized mode.
Cc: linux-hardening@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220503205503.3054173-4-keescook@chromium.org
IMA may verify a file's integrity against a "good" value stored in the
'security.ima' xattr or as an appended signature, based on policy. When
the "good value" is stored in the xattr, the xattr may contain a file
hash or signature. In either case, the "good" value is preceded by a
header. The first byte of the xattr header indicates the type of data
- hash, signature - stored in the xattr. To support storing fs-verity
signatures in the 'security.ima' xattr requires further differentiating
the fs-verity signature from the existing IMA signature.
In addition the signatures stored in 'security.ima' xattr, need to be
disambiguated. Instead of directly signing the fs-verity digest, a new
signature format version 3 is defined as the hash of the ima_file_id
structure, which identifies the type of signature and the digest.
The IMA policy defines "which" files are to be measured, verified, and/or
audited. For those files being verified, the policy rules indicate "how"
the file should be verified. For example to require a file be signed,
the appraise policy rule must include the 'appraise_type' option.
appraise_type:= [imasig] | [imasig|modsig] | [sigv3]
where 'imasig' is the original or signature format v2 (default),
where 'modsig' is an appended signature,
where 'sigv3' is the signature format v3.
The policy rule must also indicate the type of digest, if not the IMA
default, by first specifying the digest type:
digest_type:= [verity]
The following policy rule requires fsverity signatures. The rule may be
constrained, for example based on a fsuuid or LSM label.
appraise func=BPRM_CHECK digest_type=verity appraise_type=sigv3
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Permit fsverity's file digest (a hash of struct fsverity_descriptor) to
be included in the IMA measurement list, based on the new measurement
policy rule 'digest_type=verity' option.
To differentiate between a regular IMA file hash from an fsverity's
file digest, use the new d-ngv2 format field included in the ima-ngv2
template.
The following policy rule requires fsverity file digests and specifies
the new 'ima-ngv2' template, which contains the new 'd-ngv2' field. The
policy rule may be constrained, for example based on a fsuuid or LSM
label.
measure func=FILE_CHECK digest_type=verity template=ima-ngv2
Acked-by: Stefan Berger <stefanb@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Eric Snowberg