Pull integrity updates from James Morris:
"In Linux 4.19, a new LSM hook named security_kernel_load_data was
upstreamed, allowing LSMs and IMA to prevent the kexec_load syscall.
Different signature verification methods exist for verifying the
kexec'ed kernel image. This adds additional support in IMA to prevent
loading unsigned kernel images via the kexec_load syscall,
independently of the IMA policy rules, based on the runtime "secure
boot" flag. An initial IMA kselftest is included.
In addition, this pull request defines a new, separate keyring named
".platform" for storing the preboot/firmware keys needed for verifying
the kexec'ed kernel image's signature and includes the associated IMA
kexec usage of the ".platform" keyring.
(David Howell's and Josh Boyer's patches for reading the
preboot/firmware keys, which were previously posted for a different
use case scenario, are included here)"
* 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
integrity: Remove references to module keyring
ima: Use inode_is_open_for_write
ima: Support platform keyring for kernel appraisal
efi: Allow the "db" UEFI variable to be suppressed
efi: Import certificates from UEFI Secure Boot
efi: Add an EFI signature blob parser
efi: Add EFI signature data types
integrity: Load certs to the platform keyring
integrity: Define a trusted platform keyring
selftests/ima: kexec_load syscall test
ima: don't measure/appraise files on efivarfs
x86/ima: retry detecting secure boot mode
docs: Extend trusted keys documentation for TPM 2.0
x86/ima: define arch_get_ima_policy() for x86
ima: add support for arch specific policies
ima: refactor ima_init_policy()
ima: prevent kexec_load syscall based on runtime secureboot flag
x86/ima: define arch_ima_get_secureboot
integrity: support new struct public_key_signature encoding field
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: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
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: Nayna Jain <nayna@linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
Reviewed-by: James Morris <james.morris@microsoft.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Commit d43de6c780 ("akcipher: Move the RSA DER encoding check to
the crypto layer") removed the Kconfig option PUBLIC_KEY_ALGO_RSA,
but forgot to remove a 'select' to this option in the definition of
INTEGRITY_ASYMMETRIC_KEYS.
Let's remove the select, as it's ineffective now.
Signed-off-by: Andreas Ziegler <andreas.ziegler@fau.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Convert asymmetric_verify to akcipher api.
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David Howells <dhowells@redhat.com>
CONFIG_KEYS_DEBUG_PROC_KEYS is no longer an option as /proc/keys is now
mandatory if the keyrings facility is enabled (it's used by libkeyutils in
userspace).
The defconfig references were removed with:
perl -p -i -e 's/CONFIG_KEYS_DEBUG_PROC_KEYS=y\n//' \
`git grep -l CONFIG_KEYS_DEBUG_PROC_KEYS=y`
and the integrity Kconfig fixed by hand.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Andreas Ziegler <andreas.ziegler@fau.de>
cc: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Require all keys added to the EVM keyring be signed by an
existing trusted key on the system trusted keyring.
This patch also switches IMA to use integrity_init_keyring().
Changes in v3:
* Added 'init_keyring' config based variable to skip initializing
keyring instead of using __integrity_init_keyring() wrapper.
* Added dependency back to CONFIG_IMA_TRUSTED_KEYRING
Changes in v2:
* Replace CONFIG_EVM_TRUSTED_KEYRING with IMA and EVM common
CONFIG_INTEGRITY_TRUSTED_KEYRING configuration option
* Deprecate CONFIG_IMA_TRUSTED_KEYRING but keep it for config
file compatibility. (Mimi Zohar)
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Support for keyword 'boolean' will be dropped later on.
No functional change.
Reference: http://lkml.kernel.org/r/cover.1418003065.git.cj@linux.com
Signed-off-by: Christoph Jaeger <cj@linux.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
The integrity subsystem has lots of options and takes more than
half of the security menu. This patch consolidates the options
under "integrity", which are hidden if not enabled. This change
does not affect existing configurations. Re-configuration is not
needed.
Changes v4:
- no need to change "integrity subsystem" to menuconfig as
options are hidden, when not enabled. (Mimi)
- add INTEGRITY Kconfig help description
Changes v3:
- dependency to INTEGRITY removed when behind 'if INTEGRITY'
Changes v2:
- previous patch moved integrity out of the 'security' menu.
This version keeps integrity as a security option (Mimi).
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
For better visual appearance it is better to co-locate
asymmetric key options together with signature support.
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This patch moves the integrity_audit_msg() function and defintion to
security/integrity/, the parent directory, renames the 'ima_audit'
boot command line option to 'integrity_audit', and fixes the Kconfig
help text to reflect the actual code.
Changelog:
- Fixed ifdef inclusion of integrity_audit_msg() (Fengguang Wu)
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Asymmetric keys were introduced in linux-3.7 to verify the signature on
signed kernel modules. The asymmetric keys infrastructure abstracts the
signature verification from the crypto details. This patch adds IMA/EVM
signature verification using asymmetric keys. Support for additional
signature verification methods can now be delegated to the asymmetric
key infrastructure.
Although the module signature header and the IMA/EVM signature header
could use the same format, to minimize the signature length and save
space in the extended attribute, this patch defines a new IMA/EVM
header format. The main difference is that the key identifier is a
sha1[12 - 19] hash of the key modulus and exponent, similar to the
current implementation. The only purpose of the key identifier is to
identify the corresponding key in the kernel keyring. ima-evm-utils
was updated to support the new signature format.
While asymmetric signature verification functionality supports many
different hash algorithms, the hash used in this patch is calculated
during the IMA collection phase, based on the configured algorithm.
The default algorithm is sha1, but for backwards compatibility md5
is supported. Due to this current limitation, signatures should be
generated using a sha1 hash algorithm.
Changes in this patch:
- Functionality has been moved to separate source file in order to get rid of
in source #ifdefs.
- keyid is derived according to the RFC 3280. It does not require to assign
IMA/EVM specific "description" when loading X509 certificate. Kernel
asymmetric key subsystem automatically generate the description. Also
loading a certificate does not require using of ima-evm-utils and can be
done using keyctl only.
- keyid size is reduced to 32 bits to save xattr space. Key search is done
using partial match functionality of asymmetric_key_match().
- Kconfig option title was changed
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Similar to SIGNATURE, rename INTEGRITY_DIGSIG to INTEGRITY_SIGNATURE.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>
It was reported that DIGSIG is confusing name for digital signature
module. It was suggested to rename DIGSIG to SIGNATURE.
Requested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>
Fix build errors by adding Kconfig dependency on KEYS.
CRYPTO dependency removed.
CC security/integrity/digsig.o
security/integrity/digsig.c: In function ?integrity_digsig_verify?:
security/integrity/digsig.c:38:4: error: implicit declaration of function ?request_key?
security/integrity/digsig.c:38:17: error: ?key_type_keyring? undeclared (first use in this function)
security/integrity/digsig.c:38:17: note: each undeclared identifier is reported only once for each function it appears in
make[2]: *** [security/integrity/digsig.o] Error 1
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>
Define separate keyrings for each of the different use cases - evm, ima,
and modules. Using different keyrings improves search performance, and also
allows "locking" specific keyring to prevent adding new keys.
This is useful for evm and module keyrings, when keys are usually only
added from initramfs.
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
EVM protects a file's security extended attributes(xattrs) against integrity
attacks. This patchset provides the framework and an initial method. The
initial method maintains an HMAC-sha1 value across the security extended
attributes, storing the HMAC value as the extended attribute 'security.evm'.
Other methods of validating the integrity of a file's metadata will be posted
separately (eg. EVM-digital-signatures).
While this patchset does authenticate the security xattrs, and
cryptographically binds them to the inode, coming extensions will bind other
directory and inode metadata for more complete protection. To help simplify
the review and upstreaming process, each extension will be posted separately
(eg. IMA-appraisal, IMA-appraisal-directory). For a general overview of the
proposed Linux integrity subsystem, refer to Dave Safford's whitepaper:
http://downloads.sf.net/project/linux-ima/linux-ima/Integrity_overview.pdf.
EVM depends on the Kernel Key Retention System to provide it with a
trusted/encrypted key for the HMAC-sha1 operation. The key is loaded onto the
root's keyring using keyctl. Until EVM receives notification that the key has
been successfully loaded onto the keyring (echo 1 > <securityfs>/evm), EVM can
not create or validate the 'security.evm' xattr, but returns INTEGRITY_UNKNOWN.
Loading the key and signaling EVM should be done as early as possible. Normally
this is done in the initramfs, which has already been measured as part of the
trusted boot. For more information on creating and loading existing
trusted/encrypted keys, refer to Documentation/keys-trusted-encrypted.txt. A
sample dracut patch, which loads the trusted/encrypted key and enables EVM, is
available from http://linux-ima.sourceforge.net/#EVM.
Based on the LSMs enabled, the set of EVM protected security xattrs is defined
at compile. EVM adds the following three calls to the existing security hooks:
evm_inode_setxattr(), evm_inode_post_setxattr(), and evm_inode_removexattr. To
initialize and update the 'security.evm' extended attribute, EVM defines three
calls: evm_inode_post_init(), evm_inode_post_setattr() and
evm_inode_post_removexattr() hooks. To verify the integrity of a security
xattr, EVM exports evm_verifyxattr().
Changelog v7:
- Fixed URL in EVM ABI documentation
Changelog v6: (based on Serge Hallyn's review)
- fix URL in patch description
- remove evm_hmac_size definition
- use SHA1_DIGEST_SIZE (removed both MAX_DIGEST_SIZE and evm_hmac_size)
- moved linux include before other includes
- test for crypto_hash_setkey failure
- fail earlier for invalid key
- clear entire encrypted key, even on failure
- check xattr name length before comparing xattr names
Changelog:
- locking based on i_mutex, remove evm_mutex
- using trusted/encrypted keys for storing the EVM key used in the HMAC-sha1
operation.
- replaced crypto hash with shash (Dmitry Kasatkin)
- support for additional methods of verifying the security xattrs
(Dmitry Kasatkin)
- iint not allocated for all regular files, but only for those appraised
- Use cap_sys_admin in lieu of cap_mac_admin
- Use __vfs_setxattr_noperm(), without permission checks, from EVM
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Move the inode integrity data(iint) management up to the integrity directory
in order to share the iint among the different integrity models.
Changelog:
- don't define MAX_DIGEST_SIZE
- rename several globally visible 'ima_' prefixed functions, structs,
locks, etc to 'integrity_'
- replace '20' with SHA1_DIGEST_SIZE
- reflect location change in appropriate Kconfig and Makefiles
- remove unnecessary initialization of iint_initialized to 0
- rebased on current ima_iint.c
- define integrity_iint_store/lock as static
There should be no other functional changes.
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
