kernel/linux.git/security/integrity/evm/evm.h, branch v6.4

evm: Clean up some variables

2022-05-16T12:14:38+00:00

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 Signed-off-by: Mimi Zohar

evm: Verify portable signatures against all protected xattrs

2021-06-01T19:17:31+00:00

Currently, the evm_config_default_xattrnames array contains xattr names only related to LSMs which are enabled in the kernel configuration. However, EVM portable signatures do not depend on local information and a vendor might include in the signature calculation xattrs that are not enabled in the target platform. Just including all xattrs names in evm_config_default_xattrnames is not a safe approach, because a target system might have already calculated signatures or HMACs based only on the enabled xattrs. After applying this patch, EVM would verify those signatures and HMACs with all xattrs instead. The non-enabled ones, which could possibly exist, would cause a verification error. Thus, this patch adds a new field named enabled to the xattr_list structure, which is set to true if the LSM associated to a given xattr name is enabled in the kernel configuration. The non-enabled xattrs are taken into account only in evm_calc_hmac_or_hash(), if the passed security.evm type is EVM_XATTR_PORTABLE_DIGSIG. The new function evm_protected_xattr_if_enabled() has been defined so that IMA can include all protected xattrs and not only the enabled ones in the measurement list, if the new template fields xattrnames, xattrlengths or xattrvalues have been included in the template format. Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

2019-06-05T15:37:17+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 of the license extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 315 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Armijn Hemel Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de Signed-off-by: Greg Kroah-Hartman

evm: Allow non-SHA1 digital signatures

2018-07-18T11:27:22+00:00

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: Matthew Garrett Signed-off-by: Mimi Zohar

EVM: turn evm_config_xattrnames into a list

2018-05-18T19:34:36+00:00

Use a list of xattrs rather than an array - this makes it easier to extend the list at runtime. Signed-off-by: Matthew Garrett Reviewed-by: James Morris Signed-off-by: Mimi Zohar

evm: Move evm_hmac and evm_hash from evm_main.c to evm_crypto.c

2018-03-23T10:31:37+00:00

These variables are not used where they are was defined. There is no point in declaring them there as extern. Move and constify them, saving 2 bytes. Function old new delta init_desc 273 271 -2 Total: Before=2112094, After=2112092, chg -0.00% Signed-off-by: Hernán Gonzalez Tested-by: Fengguang Wu Signed-off-by: Mimi Zohar

EVM: Add support for portable signature format

2017-12-11T22:20:39+00:00

The EVM signature includes the inode number and (optionally) the filesystem UUID, making it impractical to ship EVM signatures in packages. This patch adds a new portable format intended to allow distributions to include EVM signatures. It is identical to the existing format but hardcodes the inode and generation numbers to 0 and does not include the filesystem UUID even if the kernel is configured to do so. Removing the inode means that the metadata and signature from one file could be copied to another file without invalidating it. This is avoided by ensuring that an IMA xattr is present during EVM validation. Portable signatures are intended to be immutable - ie, they will never be transformed into HMACs. Based on earlier work by Dmitry Kasatkin and Mikhail Kurinnoi. Signed-off-by: Matthew Garrett Cc: Dmitry Kasatkin Cc: Mikhail Kurinnoi Signed-off-by: Mimi Zohar

EVM: Allow userland to permit modification of EVM-protected metadata

2017-12-11T19:27:31+00:00

When EVM is enabled it forbids modification of metadata protected by EVM unless there is already a valid EVM signature. If any modification is made, the kernel will then generate a new EVM HMAC. However, this does not map well on use cases which use only asymmetric EVM signatures, as in this scenario the kernel is unable to generate new signatures. This patch extends the /sys/kernel/security/evm interface to allow userland to request that modification of these xattrs be permitted. This is only permitted if no keys have already been loaded. In this configuration, modifying the metadata will invalidate the EVM appraisal on the file in question. This allows packaging systems to write out new files, set the relevant extended attributes and then move them into place. There's also some refactoring of the use of evm_initialized in order to avoid heading down codepaths that assume there's a key available. Signed-off-by: Matthew Garrett Signed-off-by: Mimi Zohar

EVM: Allow userspace to signal an RSA key has been loaded

2017-11-08T20:16:36+00:00

EVM will only perform validation once a key has been loaded. This key may either be a symmetric trusted key (for HMAC validation and creation) or the public half of an asymmetric key (for digital signature validation). The /sys/kernel/security/evm interface allows userland to signal that a symmetric key has been loaded, but does not allow userland to signal that an asymmetric public key has been loaded. This patch extends the interface to permit userspace to pass a bitmask of loaded key types. It also allows userspace to block loading of a symmetric key in order to avoid a compromised system from being able to load an additional key type later. Signed-off-by: Matthew Garrett Signed-off-by: Mimi Zohar

evm: enable EVM when X509 certificate is loaded

2015-12-15T13:50:48+00:00

In order to enable EVM before starting the 'init' process, evm_initialized needs to be non-zero. Previously non-zero indicated that the HMAC key was loaded. When EVM loads the X509 before calling 'init', with this patch it is now possible to enable EVM to start signature based verification. This patch defines bits to enable EVM if a key of any type is loaded. Changes in v3: * print error message if key is not set Changes in v2: * EVM_STATE_KEY_SET replaced by EVM_INIT_HMAC * EVM_STATE_X509_SET replaced by EVM_INIT_X509 Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar