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git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
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 9d1f8be5cf42 ("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
...
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I accidentally typoed this #ifdef, so verification would always be
disabled.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reported-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
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No reason for these not to be const.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Suggested-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Print the content of current->comm in messages generated by lockdown to
indicate a restriction that was hit. This makes it a bit easier to find
out what caused the message.
The message now patterned something like:
Lockdown: <comm>: <what> is restricted; see man kernel_lockdown.7
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>
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efivar_ssdt_load allows the kernel to import arbitrary ACPI code from an
EFI variable, which gives arbitrary code execution in ring 0. Prevent
that when the kernel is locked down.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: linux-efi@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Tracefs may release more information about the kernel than desirable, so
restrict it when the kernel is locked down in confidentiality mode by
preventing open().
(Fixed by Ben Hutchings to avoid a null dereference in
default_file_open())
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
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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>
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Systems in lockdown mode should block the kexec of untrusted kernels.
For x86 and ARM we can ensure that a kernel is trustworthy by validating
a PE signature, but this isn't possible on other architectures. On those
platforms we can use IMA digital signatures instead. Add a function to
determine whether IMA has or will verify signatures for a given event type,
and if so permit kexec_file() even if the kernel is otherwise locked down.
This is restricted to cases where CONFIG_INTEGRITY_TRUSTED_KEYRING is set
in order to prevent an attacker from loading additional keys at runtime.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: linux-integrity@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Disallow the use of certain perf facilities that might allow userspace to
access kernel data.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
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bpf_read() and bpf_read_str() could potentially be abused to (eg) allow
private keys in kernel memory to be leaked. Disable them if the kernel
has been locked down in confidentiality mode.
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: netdev@vger.kernel.org
cc: Chun-Yi Lee <jlee@suse.com>
cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: James Morris <jmorris@namei.org>
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Disallow the creation of perf and ftrace kprobes when the kernel is
locked down in confidentiality mode by preventing their registration.
This prevents kprobes from being used to access kernel memory to steal
crypto data, but continues to allow the use of kprobes from signed
modules.
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: davem@davemloft.net
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
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Disallow access to /proc/kcore when the kernel is locked down to prevent
access to cryptographic data. This is limited to lockdown
confidentiality mode and is still permitted in integrity mode.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>
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The testmmiotrace module shouldn't be permitted when the kernel is locked
down as it can be used to arbitrarily read and write MMIO space. This is
a runtime check rather than buildtime in order to allow configurations
where the same kernel may be run in both locked down or permissive modes
depending on local policy.
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: David Howells <dhowells@redhat.com
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: Thomas Gleixner <tglx@linutronix.de>
cc: Steven Rostedt <rostedt@goodmis.org>
cc: Ingo Molnar <mingo@kernel.org>
cc: "H. Peter Anvin" <hpa@zytor.com>
cc: x86@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Provided an annotation for module parameters that specify hardware
parameters (such as io ports, iomem addresses, irqs, dma channels, fixed
dma buffers and other types).
Suggested-by: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
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Lock down TIOCSSERIAL as that can be used to change the ioport and irq
settings on a serial port. This only appears to be an issue for the serial
drivers that use the core serial code. All other drivers seem to either
ignore attempts to change port/irq or give an error.
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Prohibit replacement of the PCMCIA Card Information Structure when the
kernel is locked down.
Suggested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: James Morris <jmorris@namei.org>
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>From the kernel documentation (initrd_table_override.txt):
If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible
to override nearly any ACPI table provided by the BIOS with an
instrumented, modified one.
When lockdown is enabled, the kernel should disallow any unauthenticated
changes to kernel space. ACPI tables contain code invoked by the kernel,
so do not allow ACPI tables to be overridden if the kernel is locked down.
Signed-off-by: Linn Crosetto <lcrosetto@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: linux-acpi@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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This option allows userspace to pass the RSDP address to the kernel, which
makes it possible for a user to modify the workings of hardware. Reject
the option when the kernel is locked down. This requires some reworking
of the existing RSDP command line logic, since the early boot code also
makes use of a command-line passed RSDP when locating the SRAT table
before the lockdown code has been initialised. This is achieved by
separating the command line RSDP path in the early boot code from the
generic RSDP path, and then copying the command line RSDP into boot
params in the kernel proper if lockdown is not enabled. If lockdown is
enabled and an RSDP is provided on the command line, this will only be
used when parsing SRAT (which shouldn't permit kernel code execution)
and will be ignored in the rest of the kernel.
(Modified by Matthew Garrett in order to handle the early boot RSDP
environment)
Signed-off-by: Josh Boyer <jwboyer@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: Dave Young <dyoung@redhat.com>
cc: linux-acpi@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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custom_method effectively allows arbitrary access to system memory, making
it possible for an attacker to circumvent restrictions on module loading.
Disable it if the kernel is locked down.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: linux-acpi@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Writing to MSRs should not be allowed if the kernel is locked down, since
it could lead to execution of arbitrary code in kernel mode. Based on a
patch by Kees Cook.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
cc: x86@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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IO port access would permit users to gain access to PCI configuration
registers, which in turn (on a lot of hardware) give access to MMIO
register space. This would potentially permit root to trigger arbitrary
DMA, so lock it down by default.
This also implicitly locks down the KDADDIO, KDDELIO, KDENABIO and
KDDISABIO console ioctls.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: x86@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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Any hardware that can potentially generate DMA has to be locked down in
order to avoid it being possible for an attacker to modify kernel code,
allowing them to circumvent disabled module loading or module signing.
Default to paranoid - in future we can potentially relax this for
sufficiently IOMMU-isolated devices.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: linux-pci@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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There is currently no way to verify the resume image when returning
from hibernate. This might compromise the signed modules trust model,
so until we can work with signed hibernate images we disable it when the
kernel is locked down.
Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: rjw@rjwysocki.net
Cc: pavel@ucw.cz
cc: linux-pm@vger.kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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When KEXEC_SIG is not enabled, kernel should not load images through
kexec_file systemcall if the kernel is locked down.
[Modified by David Howells to fit with modifications to the previous patch
and to return -EPERM if the kernel is locked down for consistency with
other lockdowns. Modified by Matthew Garrett to remove the IMA
integration, which will be replaced by integrating with the IMA
architecture policy patches.]
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
cc: kexec@lists.infradead.org
Signed-off-by: James Morris <jmorris@namei.org>
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This is a preparatory patch for kexec_file_load() lockdown. A locked down
kernel needs to prevent unsigned kernel images from being loaded with
kexec_file_load(). Currently, the only way to force the signature
verification is compiling with KEXEC_VERIFY_SIG. This prevents loading
usigned images even when the kernel is not locked down at runtime.
This patch splits KEXEC_VERIFY_SIG into KEXEC_SIG and KEXEC_SIG_FORCE.
Analogous to the MODULE_SIG and MODULE_SIG_FORCE for modules, KEXEC_SIG
turns on the signature verification but allows unsigned images to be
loaded. KEXEC_SIG_FORCE disallows images without a valid signature.
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
cc: kexec@lists.infradead.org
Signed-off-by: James Morris <jmorris@namei.org>
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Kexec reboot in case secure boot being enabled does not keep the secure
boot mode in new kernel, so later one can load unsigned kernel via legacy
kexec_load. In this state, the system is missing the protections provided
by secure boot.
Adding a patch to fix this by retain the secure_boot flag in original
kernel.
secure_boot flag in boot_params is set in EFI stub, but kexec bypasses the
stub. Fixing this issue by copying secure_boot flag across kexec reboot.
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: kexec@lists.infradead.org
Signed-off-by: James Morris <jmorris@namei.org>
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The kexec_load() syscall permits the loading and execution of arbitrary
code in ring 0, which is something that lock-down is meant to prevent. It
makes sense to disable kexec_load() in this situation.
This does not affect kexec_file_load() syscall which can check for a
signature on the image to be booted.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Dave Young <dyoung@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
cc: kexec@lists.infradead.org
Signed-off-by: James Morris <jmorris@namei.org>
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Allowing users to read and write to core kernel memory makes it possible
for the kernel to be subverted, avoiding module loading restrictions, and
also to steal cryptographic information.
Disallow /dev/mem and /dev/kmem from being opened this when the kernel has
been locked down to prevent this.
Also disallow /dev/port from being opened to prevent raw ioport access and
thus DMA from being used to accomplish the same thing.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: x86@kernel.org
Signed-off-by: James Morris <jmorris@namei.org>
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If the kernel is locked down, require that all modules have valid
signatures that we can verify.
I have adjusted the errors generated:
(1) If there's no signature (ENODATA) or we can't check it (ENOPKG,
ENOKEY), then:
(a) If signatures are enforced then EKEYREJECTED is returned.
(b) If there's no signature or we can't check it, but the kernel is
locked down then EPERM is returned (this is then consistent with
other lockdown cases).
(2) If the signature is unparseable (EBADMSG, EINVAL), the signature fails
the check (EKEYREJECTED) or a system error occurs (eg. ENOMEM), we
return the error we got.
Note that the X.509 code doesn't check for key expiry as the RTC might not
be valid or might not have been transferred to the kernel's clock yet.
[Modified by Matthew Garrett to remove the IMA integration. This will
be replaced with integration with the IMA architecture policy
patchset.]
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Matthew Garrett <matthewgarrett@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Jessica Yu <jeyu@kernel.org>
Signed-off-by: James Morris <jmorris@namei.org>
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While existing LSMs can be extended to handle lockdown policy,
distributions generally want to be able to apply a straightforward
static policy. This patch adds a simple LSM that can be configured to
reject either integrity or all lockdown queries, and can be configured
at runtime (through securityfs), boot time (via a kernel parameter) or
build time (via a kconfig option). Based on initial code by David
Howells.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
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Add a mechanism 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.
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: James Morris <jmorris@namei.org>
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The lockdown module is intended to allow for kernels to be locked down
early in boot - sufficiently early that we don't have the ability to
kmalloc() yet. Add support for early initialisation of some LSMs, and
then add them to the list of names when we do full initialisation later.
Early LSMs are initialised in link order and cannot be overridden via
boot parameters, and cannot make use of kmalloc() (since the allocator
isn't initialised yet).
(Fixed by Stephen Rothwell to include a stub to fix builds when
!CONFIG_SECURITY)
Signed-off-by: Matthew Garrett <mjg59@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: James Morris <jmorris@namei.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
"The major feature in this time is IMA support for measuring and
appraising appended file signatures. In addition are a couple of bug
fixes and code cleanup to use struct_size().
In addition to the PE/COFF and IMA xattr signatures, the kexec kernel
image may be signed with an appended signature, using the same
scripts/sign-file tool that is used to sign kernel modules.
Similarly, the initramfs may contain an appended signature.
This contained a lot of refactoring of the existing appended signature
verification code, so that IMA could retain the existing framework of
calculating the file hash once, storing it in the IMA measurement list
and extending the TPM, verifying the file's integrity based on a file
hash or signature (eg. xattrs), and adding an audit record containing
the file hash, all based on policy. (The IMA support for appended
signatures patch set was posted and reviewed 11 times.)
The support for appended signature paves the way for adding other
signature verification methods, such as fs-verity, based on a single
system-wide policy. The file hash used for verifying the signature and
the signature, itself, can be included in the IMA measurement list"
* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
ima: ima_api: Use struct_size() in kzalloc()
ima: use struct_size() in kzalloc()
sefltest/ima: support appended signatures (modsig)
ima: Fix use after free in ima_read_modsig()
MODSIGN: make new include file self contained
ima: fix freeing ongoing ahash_request
ima: always return negative code for error
ima: Store the measurement again when appraising a modsig
ima: Define ima-modsig template
ima: Collect modsig
ima: Implement support for module-style appended signatures
ima: Factor xattr_verify() out of ima_appraise_measurement()
ima: Add modsig appraise_type option for module-style appended signatures
integrity: Select CONFIG_KEYS instead of depending on it
PKCS#7: Introduce pkcs7_get_digest()
PKCS#7: Refactor verify_pkcs7_signature()
MODSIGN: Export module signature definitions
ima: initialize the "template" field with the default template
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One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct ima_template_entry {
...
struct ima_field_data template_data[0]; /* template related data */
};
instance = kzalloc(sizeof(struct ima_template_entry) + count * sizeof(struct ima_field_data), GFP_NOFS);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_NOFS);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
struct boo entry[];
};
instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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In addition to the PE/COFF and IMA xattr signatures, the kexec kernel
image can be signed with an appended signature, using the same
scripts/sign-file tool that is used to sign kernel modules.
This patch adds support for detecting a kernel image signed with an
appended signature and updates the existing test messages
appropriately.
Reviewed-by: Petr Vorel <pvorel@suse.cz>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Jordan Hand <jorhand@linux.microsoft.com> (x86_64 QEMU)
Tested-by: Jordan Hand <jorhand@linux.microsoft.com> (x86_64 QEMU)
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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If we can't parse the PKCS7 in the appended modsig, we will free the modsig
structure and then access one of its members to determine the error value.
Fixes: 39b07096364a ("ima: Implement support for module-style appended signatures")
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Fixes: c8424e776b09 ("MODSIGN: Export module signature definitions")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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integrity_kernel_read() can fail in which case we forward to call
ahash_request_free() on a currently running request. We have to wait
for its completion before we can free the request.
This was observed by interrupting a "find / -type f -xdev -print0 | xargs -0
cat 1>/dev/null" with ctrl-c on an IMA enabled filesystem.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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integrity_kernel_read() returns the number of bytes read. If this is
a short read then this positive value is returned from
ima_calc_file_hash_atfm(). Currently this is only indirectly called from
ima_calc_file_hash() and this function only tests for the return value
being zero or nonzero and also doesn't forward the return value.
Nevertheless there's no point in returning a positive value as an error,
so translate a short read into -EINVAL.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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If the IMA template contains the "modsig" or "d-modsig" field, then the
modsig should be added to the measurement list when the file is appraised.
And that is what normally happens, but if a measurement rule caused a file
containing a modsig to be measured before a different rule causes it to be
appraised, the resulting measurement entry will not contain the modsig
because it is only fetched during appraisal. When the appraisal rule
triggers, it won't store a new measurement containing the modsig because
the file was already measured.
We need to detect that situation and store an additional measurement with
the modsig. This is done by adding an IMA_MEASURE action flag if we read a
modsig and the IMA template contains a modsig field.
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Define new "d-modsig" template field which holds the digest that is
expected to match the one contained in the modsig, and also new "modsig"
template field which holds the appended file signature.
Add a new "ima-modsig" defined template descriptor with the new fields as
well as the ones from the "ima-sig" descriptor.
Change ima_store_measurement() to accept a struct modsig * argument so that
it can be passed along to the templates via struct ima_event_data.
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Obtain the modsig and calculate its corresponding hash in
ima_collect_measurement().
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Implement the appraise_type=imasig|modsig option, allowing IMA to read and
verify modsig signatures.
In case a file has both an xattr signature and an appended modsig, IMA will
only use the appended signature if the key used by the xattr signature
isn't present in the IMA or platform keyring.
Because modsig verification needs to convert from an integrity keyring id
to the keyring itself, add an integrity_keyring_from_id() function in
digsig.c so that integrity_modsig_verify() can use it.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Verify xattr signature in a separate function so that the logic in
ima_appraise_measurement() remains clear when it gains the ability to also
verify an appended module signature.
The code in the switch statement is unchanged except for having to
dereference the status and cause variables (since they're now pointers),
and fixing the style of a block comment to appease checkpatch.
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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Introduce the modsig keyword to the IMA policy syntax to specify that
a given hook should expect the file to have the IMA signature appended
to it. Here is how it can be used in a rule:
appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig
With this rule, IMA will accept either a signature stored in the extended
attribute or an appended signature.
For now, the rule above will behave exactly the same as if
appraise_type=imasig was specified. The actual modsig implementation
will be introduced separately.
Suggested-by: Mimi Zohar <zohar@linux.ibm.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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This avoids a dependency cycle in soon-to-be-introduced
CONFIG_IMA_APPRAISE_MODSIG: it will select CONFIG_MODULE_SIG_FORMAT
which in turn selects CONFIG_KEYS. Kconfig then complains that
CONFIG_INTEGRITY_SIGNATURE depends on CONFIG_KEYS.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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IMA will need to access the digest of the PKCS7 message (as calculated by
the kernel) before the signature is verified, so introduce
pkcs7_get_digest() for that purpose.
Also, modify pkcs7_digest() to detect when the digest was already
calculated so that it doesn't have to do redundant work. Verifying that
sinfo->sig->digest isn't NULL is sufficient because both places which
allocate sinfo->sig (pkcs7_parse_message() and pkcs7_note_signed_info())
use kzalloc() so sig->digest is always initialized to zero.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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IMA will need to verify a PKCS#7 signature which has already been parsed.
For this reason, factor out the code which does that from
verify_pkcs7_signature() into a new function which takes a struct
pkcs7_message instead of a data buffer.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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IMA will use the module_signature format for append signatures, so export
the relevant definitions and factor out the code which verifies that the
appended signature trailer is valid.
Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it
and be able to use mod_check_sig() without having to depend on either
CONFIG_MODULE_SIG or CONFIG_MODULES.
s390 duplicated the definition of struct module_signature so now they can
use the new <linux/module_signature.h> header instead.
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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