If tmpfiles can be made persistent, then newly created tmpfiles need to
be treated like any other new files in policy.

This patch indicates which newly created tmpfiles are in policy, causing
the file hash to be calculated on __fput().
Reported-by: NIgnaz Forster <ignaz.forster@gmx.de>
[rgoldwyn@suse.com: Call ima_post_create_tmpfile() in vfs_tmpfile() as
opposed to do_tmpfile(). This will help the case for overlayfs where
copy_up is denied while overwriting a file.]
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Fixes gcc '-Wunused-but-set-variable' warning:

security/integrity/evm/evm_main.c: In function 'init_evm':
security/integrity/evm/evm_main.c:566:21: warning:
 variable 'xattr' set but not used [-Wunused-but-set-variable]

Commit 21af7663 ("EVM: turn evm_config_xattrnames into a list")
defined and set "xattr", but never used it.

[zohar@linux.ibm.com: tweaked the patch description explanation]
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

commit 9dc92c45 ("integrity: Define a trusted platform keyring")
introduced a .platform keyring for storing preboot keys, used for
verifying kernel image signatures. Currently only IMA-appraisal is able
to use the keyring to verify kernel images that have their signature
stored in xattr.

This patch exposes the .platform keyring, making it accessible for
verifying PE signed kernel images as well.
Suggested-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NKairui Song <kasong@redhat.com>
Cc: David Howells <dhowells@redhat.com>
[zohar@linux.ibm.com: fixed checkpatch errors, squashed with patch fix]
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

totalram_pages and totalhigh_pages are made static inline function.

Main motivation was that managed_page_count_lock handling was complicating
things.  It was discussed in length here,
https://lore.kernel.org/patchwork/patch/995739/#1181785 So it seemes
better to remove the lock and convert variables to atomic, with preventing
poteintial store-to-read tearing as a bonus.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/1542090790-21750-4-git-send-email-arunks@codeaurora.orgSigned-off-by: NArun KS <arunks@codeaurora.org>
Suggested-by: NMichal Hocko <mhocko@suse.com>
Suggested-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Reviewed-by: NPavel Tatashin <pasha.tatashin@soleen.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The Kconfig lexer supports special characters such as '.' and '/' in
the parameter context. In my understanding, the reason is just to
support bare file paths in the source statement.

I do not see a good reason to complicate Kconfig for the room of
ambiguity.

The majority of code already surrounds file paths with double quotes,
and it makes sense since file paths are constant string literals.

Make it treewide consistent now.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NIngo Molnar <mingo@kernel.org>

In commit 4f83d5ea ("security: integrity: make ima_main explicitly
non-modular") I'd removed <linux/module.h> after assuming that the
function is_module_sig_enforced() was an LSM function and not a core
kernel module function.

Unfortunately the typical .config selections used in build testing
provide an implicit <linux/module.h> presence, and so normal/typical
build testing did not immediately reveal my incorrect assumption.

Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-ima-devel@lists.sourceforge.net
Cc: linux-security-module@vger.kernel.org
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Start the policy_tokens and the associated enumeration from zero,
simplifying the pt macro.
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

From what I can tell, it has never been used.

Mimi: This was introduced prior to Rusty's decision to use appended
signatures for kernel modules.
Signed-off-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Acked-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Use the aptly named function rather than open coding the check. No
functional changes.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

On secure boot enabled systems, the bootloader verifies the kernel
image and possibly the initramfs signatures based on a set of keys. A
soft reboot(kexec) of the system, with the same kernel image and
initramfs, requires access to the original keys to verify the
signatures.

This patch allows IMA-appraisal access to those original keys, now
loaded on the platform keyring, needed for verifying the kernel image
and initramfs signatures.

[zohar@linux.ibm.com: only use platform keyring if it's enabled (Thiago)]
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

If a user tells shim to not use the certs/hashes in the UEFI db variable
for verification purposes, shim will set a UEFI variable called
MokIgnoreDB. Have the uefi import code look for this and ignore the db
variable if it is found.

[zohar@linux.ibm.com: removed reference to "secondary" keyring comment]
Signed-off-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NNayna Jain <nayna@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Secure Boot stores a list of allowed certificates in the 'db' variable.
This patch imports those certificates into the platform keyring. The shim
UEFI bootloader has a similar certificate list stored in the 'MokListRT'
variable. We import those as well.

Secure Boot also maintains a list of disallowed certificates in the 'dbx'
variable. We load those certificates into the system blacklist keyring
and forbid any kernel signed with those from loading.

[zohar@linux.ibm.com: dropped Josh's original patch description]
Signed-off-by: NJosh Boyer <jwboyer@fedoraproject.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Add a function to parse an EFI signature blob looking for elements of
interest. A list is made up of a series of sublists, where all the
elements in a sublist are of the same type, but sublists can be of
different types.

For each sublist encountered, the function pointed to by the
get_handler_for_guid argument is called with the type specifier GUID and
returns either a pointer to a function to handle elements of that type or
NULL if the type is not of interest.

If the sublist is of interest, each element is passed to the handler
function in turn.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

The patch refactors integrity_load_x509(), making it a wrapper for a new
function named integrity_add_key(). This patch also defines a new
function named integrity_load_cert() for loading the platform keys.
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

On secure boot enabled systems, a verified kernel may need to kexec
additional kernels. For example, it may be used as a bootloader needing
to kexec a target kernel or it may need to kexec a crashdump kernel. In
such cases, it may want to verify the signature of the next kernel
image.

It is further possible that the kernel image is signed with third party
keys which are stored as platform or firmware keys in the 'db' variable.
The kernel, however, can not directly verify these platform keys, and an
administrator may therefore not want to trust them for arbitrary usage.
In order to differentiate platform keys from other keys and provide the
necessary separation of trust, the kernel needs an additional keyring to
store platform keys.

This patch creates the new keyring called ".platform" to isolate keys
provided by platform from keys by kernel. These keys are used to
facilitate signature verification during kexec. Since the scope of this
keyring is only the platform/firmware keys, it cannot be updated from
userspace.

This keyring can be enabled by setting CONFIG_INTEGRITY_PLATFORM_KEYRING.
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Reviewed-by: NMimi Zohar <zohar@linux.ibm.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Reviewed-by: NThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Historically a lot of these existed because we did not have
a distinction between what was modular code and what was providing
support to modules via EXPORT_SYMBOL and friends.  That changed
when we forked out support for the latter into the export.h file.
This means we should be able to reduce the usage of module.h
in code that is obj-y Makefile or bool Kconfig.

The advantage in removing such instances is that module.h itself
sources about 15 other headers; adding significantly to what we feed
cpp, and it can obscure what headers we are effectively using.

Since module.h might have been the implicit source for init.h
(for __init) and for export.h (for EXPORT_SYMBOL) we consider each
instance for the presence of either and replace as needed.

Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: linux-security-module@vger.kernel.org
Cc: linux-integrity@vger.kernel.org
Cc: keyrings@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

The Makefile/Kconfig entry controlling compilation of this code is:

obj-$(CONFIG_EVM) += evm.o
evm-y := evm_main.o evm_crypto.o evm_secfs.o

security/integrity/evm/Kconfig:config EVM
security/integrity/evm/Kconfig: bool "EVM support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-ima-devel@lists.sourceforge.net
Cc: linux-security-module@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

The Makefile/Kconfig entry controlling compilation of this code is:

obj-$(CONFIG_IMA) += ima.o
ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
         ima_policy.o ima_template.o ima_template_lib.o

security/integrity/ima/Kconfig:config IMA
security/integrity/ima/Kconfig- bool "Integrity Measurement Architecture(IMA)"

...meaning that it currently is not being built as a module by anyone.

Lets remove the couple traces of modular infrastructure use, so that
when reading the driver there is no doubt it is builtin-only.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

Cc: Mimi Zohar <zohar@linux.ibm.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-ima-devel@lists.sourceforge.net
Cc: linux-security-module@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Update the builtin IMA policies specified on the boot command line
(eg. ima_policy="tcb|appraise_tcb") to permit accessing efivar files.
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

On x86, there are two methods of verifying a kexec'ed kernel image
signature being loaded via the kexec_file_load syscall - an architecture
specific implementaton or a IMA KEXEC_KERNEL_CHECK appraisal rule. Neither
of these methods verify the kexec'ed kernel image signature being loaded
via the kexec_load syscall.

Secure boot enabled systems require kexec images to be signed. Therefore,
this patch loads an IMA KEXEC_KERNEL_CHECK policy rule on secure boot
enabled systems not configured with CONFIG_KEXEC_VERIFY_SIG enabled.

When IMA_APPRAISE_BOOTPARAM is configured, different IMA appraise modes
(eg. fix, log) can be specified on the boot command line, allowing unsigned
or invalidly signed kernel images to be kexec'ed. This patch permits
enabling IMA_APPRAISE_BOOTPARAM or IMA_ARCH_POLICY, but not both.
Signed-off-by: NEric Richter <erichte@linux.ibm.com>
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Builtin IMA policies can be enabled on the boot command line, and replaced
with a custom policy, normally during early boot in the initramfs. Build
time IMA policy rules were recently added. These rules are automatically
enabled on boot and persist after loading a custom policy.

There is a need for yet another type of policy, an architecture specific
policy, which is derived at runtime during kernel boot, based on the
runtime secure boot flags.  Like the build time policy rules, these rules
persist after loading a custom policy.

This patch adds support for loading an architecture specific IMA policy.
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Co-Developed-by: NMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

This patch removes the code duplication in ima_init_policy() by defining
a new function named add_rules(). The new function adds the rules to the
initial IMA policy, the custom policy or both based on the policy mask
(IMA_DEFAULT_POLICY, IMA_CUSTOM_POLICY).
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

When CONFIG_KEXEC_VERIFY_SIG is enabled, the kexec_file_load syscall
requires the kexec'd kernel image to be signed. Distros are concerned
about totally disabling the kexec_load syscall. As a compromise, the
kexec_load syscall will only be disabled when CONFIG_KEXEC_VERIFY_SIG
is configured and the system is booted with secureboot enabled.

This patch disables the kexec_load syscall only for systems booted with
secureboot enabled.

[zohar@linux.ibm.com: add missing mesage on kexec_load failure]
Signed-off-by: NNayna Jain <nayna@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

There are many places, notably audit_log_task_info() and
audit_log_exit(), that take task_struct pointers but in reality they
are always working on the current task.  This patch eliminates the
task_struct arguments and uses current directly which allows a number
of cleanups as well.
Acked-by: NRichard Guy Briggs <rgb@redhat.com>
Signed-off-by: NPaul Moore <paul@paul-moore.com>

'shash' algorithms are always synchronous, so passing CRYPTO_ALG_ASYNC
in the mask to crypto_alloc_shash() has no effect.  Many users therefore
already don't pass it, but some still do.  This inconsistency can cause
confusion, especially since the way the 'mask' argument works is
somewhat counterintuitive.

Thus, just remove the unneeded CRYPTO_ALG_ASYNC flags.

This patch shouldn't change any actual behavior.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

On systems with IMA-appraisal enabled with a policy requiring file
signatures, the "good" signature values are stored on the filesystem as
extended attributes (security.ima).  Signature verification failure
would normally be limited to just a particular file (eg. executable),
but during boot signature verification failure could result in a system
hang.

Defining and requiring a new public_key_signature field requires all
callers of asymmetric signature verification to be updated to reflect
the change.  This patch updates the integrity asymmetric_verify()
caller.

Fixes: 82f94f24 ("KEYS: Provide software public key query function [ver #2]")
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: NDenis Kenzior <denkenz@gmail.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

On systems with IMA-appraisal enabled with a policy requiring file
signatures, the "good" signature values are stored on the filesystem as
extended attributes (security.ima).  Signature verification failure
would normally be limited to just a particular file (eg. executable),
but during boot signature verification failure could result in a system
hang.

Defining and requiring a new public_key_signature field requires all
callers of asymmetric signature verification to be updated to reflect
the change.  This patch updates the integrity asymmetric_verify()
caller.

Fixes: 82f94f24 ("KEYS: Provide software public key query function [ver #2]")
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Acked-by: NDenis Kenzior <denkenz@gmail.com>

The TPM specs defines PCR index as a positive number, and there is
no reason to use a signed number. It is also a possible security
issue as currently no functions check for a negative index,
which may become a large number when converted to u32.

Adjust the API to use u32 instead of int in all PCR related
functions.
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

In preparation for making LSM selections outside of the LSMs, include
the name of LSMs in struct lsm_info.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NCasey Schaufler <casey@schaufler-ca.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Instead of using argument-based initializers, switch to defining the
contents of struct lsm_info on a per-LSM basis. This also drops
the final use of the now inaccurate "initcall" naming.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

In preparation for doing more interesting LSM init probing, this converts
the existing initcall system into an explicit call into a function pointer
from a section-collected struct lsm_info array.
Signed-off-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NCasey Schaufler <casey@schaufler-ca.com>
Reviewed-by: NJames Morris <james.morris@microsoft.com>
Reviewed-by: NJohn Johansen <john.johansen@canonical.com>
Signed-off-by: NJames Morris <james.morris@microsoft.com>

Open a new file instance as opposed to changing file->f_mode when
the file is not readable.  This is done to accomodate overlayfs
stacked file operations change.  The real struct file is hidden
behind the overlays struct file.  So, any file->f_mode manipulations are
not reflected on the real struct file.  Open the file again in read mode
if original file cannot be read, read and calculate the hash.
Signed-off-by: NGoldwyn Rodrigues <rgoldwyn@suse.com>
Cc: stable@vger.kernel.org (linux-4.19)
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

The 12 character temporary buffer is not necessarily long enough to hold
a 'long' value.  Increase it.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

The 'init_keyring' variable actually just gave the value of
CONFIG_INTEGRITY_TRUSTED_KEYRING.  We should check the config option
directly instead.  No change in behavior; this just simplifies the code.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Constify some static data that is never modified,
so that it is placed in .rodata.
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

Get rid of ima_used_chip and use ima_tpm_chip variable instead for
determining whether to use the TPM chip.
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

Rather than accessing the TPM functions by passing a NULL pointer for
the tpm_chip, which causes a lookup for a suitable chip every time, get a
hold of a tpm_chip and access the TPM functions using it.
Signed-off-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

In case of error, the function audit_log_start() returns NULL pointer
not ERR_PTR(). The IS_ERR() test in the return value check should be
replaced with NULL test.

Fixes: fa516b66 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Acked-by: NSerge Hallyn <serge@hallyn.com>
Signed-off-by: NMimi Zohar <zohar@linux.ibm.com>

This patch aimed to prevent deadlock during digsig verification.The point
of issue - user space utility modprobe and/or it's dependencies (ld-*.so,
libz.so.*, libc-*.so and /lib/modules/ files) that could be used for
kernel modules load during digsig verification and could be signed by
digsig in the same time.

First at all, look at crypto_alloc_tfm() work algorithm:
crypto_alloc_tfm() will first attempt to locate an already loaded
algorithm. If that fails and the kernel supports dynamically loadable
modules, it will then attempt to load a module of the same name or alias.
If that fails it will send a query to any loaded crypto manager to
construct an algorithm on the fly.

We have situation, when public_key_verify_signature() in case of RSA
algorithm use alg_name to store internal information in order to construct
an algorithm on the fly, but crypto_larval_lookup() will try to use
alg_name in order to load kernel module with same name.

1) we can't do anything with crypto module work, since it designed to work
exactly in this way;
2) we can't globally filter module requests for modprobe, since it
designed to work with any requests.

In this patch, I propose add an exception for "crypto-pkcs1pad(rsa,*)"
module requests only in case of enabled integrity asymmetric keys support.
Since we don't have any real "crypto-pkcs1pad(rsa,*)" kernel modules for
sure, we are safe to fail such module request from crypto_larval_lookup().
In this way we prevent modprobe execution during digsig verification and
avoid possible deadlock if modprobe and/or it's dependencies also signed
with digsig.

Requested "crypto-pkcs1pad(rsa,*)" kernel module name formed by:
1) "pkcs1pad(rsa,%s)" in public_key_verify_signature();
2) "crypto-%s" / "crypto-%s-all" in crypto_larval_lookup().
"crypto-pkcs1pad(rsa," part of request is a constant and unique and could
be used as filter.
Signed-off-by: NMikhail Kurinnoi <viewizard@viewizard.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

 include/linux/integrity.h              | 13 +++++++++++++
 security/integrity/digsig_asymmetric.c | 23 +++++++++++++++++++++++
 security/security.c                    |  7 ++++++-
 3 files changed, 42 insertions(+), 1 deletion(-)

SHA1 is reasonable in HMAC constructs, but it's desirable to be able to
use stronger hashes in digital signatures. Modify the EVM crypto code so
the hash type is imported from the digital signature and passed down to
the hash calculation code, and return the digest size to higher layers
for validation.
Signed-off-by: NMatthew Garrett <mjg59@google.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>