kernel/linux.git/security/integrity/integrity.h, branch v6.1.38

ima: support fs-verity file digest based version 3 signatures

2022-05-05T21:41:51+00:00

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 Signed-off-by: Mimi Zohar

ima: permit fsverity's file digests in the IMA measurement list

2022-05-05T15:49:13+00:00

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 Signed-off-by: Mimi Zohar

Merge tag 'integrity-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity

2022-03-22T03:44:37+00:00

Pull integrity subsystem updates from Mimi Zohar: "Except for extending the 'encrypted' key type to support user provided data, the rest is code cleanup, __setup() usage bug fix, and a trivial change" * tag 'integrity-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: MAINTAINERS: add missing security/integrity/platform_certs EVM: fix the evm= __setup handler return value KEYS: encrypted: Instantiate key with user-provided decrypted data ima: define ima_max_digest_data struct without a flexible array variable ima: rename IMA_ACTION_FLAGS to IMA_NONACTION_FLAGS ima: Return error code obtained from securityfs functions MAINTAINERS: add missing "security/integrity" directory ima: Fix trivial typos in the comments

integrity: Only use machine keyring when uefi_check_trust_mok_keys is true

2022-03-08T11:55:52+00:00

With the introduction of uefi_check_trust_mok_keys, it signifies the end- user wants to trust the machine keyring as trusted keys. If they have chosen to trust the machine keyring, load the qualifying keys into it during boot, then link it to the secondary keyring . If the user has not chosen to trust the machine keyring, it will be empty and not linked to the secondary keyring. Signed-off-by: Eric Snowberg Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

integrity: Introduce a Linux keyring called machine

2022-03-08T11:55:52+00:00

Many UEFI Linux distributions boot using shim. The UEFI shim provides what is called Machine Owner Keys (MOK). Shim uses both the UEFI Secure Boot DB and MOK keys to validate the next step in the boot chain. The MOK facility can be used to import user generated keys. These keys can be used to sign an end-users development kernel build. When Linux boots, both UEFI Secure Boot DB and MOK keys get loaded in the Linux .platform keyring. Define a new Linux keyring called machine. This keyring shall contain just MOK keys and not the remaining keys in the platform keyring. This new machine keyring will be used in follow on patches. Unlike keys in the platform keyring, keys contained in the machine keyring will be trusted within the kernel if the end-user has chosen to do so. Signed-off-by: Eric Snowberg Tested-by: Jarkko Sakkinen Tested-by: Mimi Zohar Reviewed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen

ima: define ima_max_digest_data struct without a flexible array variable

2022-02-15T16:52:06+00:00

To support larger hash digests in the 'iint' cache, instead of defining the 'digest' field as the maximum digest size, the 'digest' field was defined as a flexible array variable. The "ima_digest_data" struct was wrapped inside a local structure with the maximum digest size. But before adding the record to the iint cache, memory for the exact digest size was dynamically allocated. The original reason for defining the 'digest' field as a flexible array variable is still valid for the 'iint' cache use case. Instead of wrapping the 'ima_digest_data' struct in a local structure define 'ima_max_digest_data' struct. Reviewed-by: Stefan Berger Signed-off-by: Mimi Zohar

ima: rename IMA_ACTION_FLAGS to IMA_NONACTION_FLAGS

2022-02-15T16:21:59+00:00

Simple policy rule options, such as fowner, uid, or euid, can be checked immediately, while other policy rule options, such as requiring a file signature, need to be deferred. The 'flags' field in the integrity_iint_cache struct contains the policy action', 'subaction', and non action/subaction. action: measure/measured, appraise/appraised, (collect)/collected, audit/audited subaction: appraise status for each hook (e.g. file, mmap, bprm, read, creds) non action/subaction: deferred policy rule options and state Rename the IMA_ACTION_FLAGS to IMA_NONACTION_FLAGS. Reviewed-by: Stefan Berger Signed-off-by: Mimi Zohar

crypto: sha - split sha.h into sha1.h and sha2.h

2020-11-20T03:45:33+00:00

Currently contains declarations for both SHA-1 and SHA-2, and contains declarations for SHA-3. This organization is inconsistent, but more importantly SHA-1 is no longer considered to be cryptographically secure. So to the extent possible, SHA-1 shouldn't be grouped together with any of the other SHA versions, and usage of it should be phased out. Therefore, split into two headers and , and make everyone explicitly specify whether they want the declarations for SHA-1, SHA-2, or both. This avoids making the SHA-1 declarations visible to files that don't want anything to do with SHA-1. It also prepares for potentially moving sha1.h into a new insecure/ or dangerous/ directory. Signed-off-by: Eric Biggers Acked-by: Ard Biesheuvel Acked-by: Jason A. Donenfeld Signed-off-by: Herbert Xu

integrity: Add errno field in audit message

2020-07-17T01:48:11+00:00

Error code is not included in the audit messages logged by the integrity subsystem. Define a new function integrity_audit_message() that takes error code in the "errno" parameter. Add "errno" field in the audit messages logged by the integrity subsystem and set the value passed in the "errno" parameter. [ 6.303048] audit: type=1804 audit(1592506281.627:2): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=kernel op=measuring_key cause=ENOMEM comm="swapper/0" name=".builtin_trusted_keys" res=0 errno=-12 [ 7.987647] audit: type=1802 audit(1592506283.312:9): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=policy_update cause=completed comm="systemd" res=1 errno=0 [ 8.019432] audit: type=1804 audit(1592506283.344:10): pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 op=measuring_kexec_cmdline cause=hashing_error comm="systemd" name="kexec-cmdline" res=0 errno=-22 Signed-off-by: Lakshmi Ramasubramanian Suggested-by: Steve Grubb Suggested-by: Mimi Zohar Signed-off-by: Mimi Zohar

ima: Replace zero-length array with flexible-array

2020-06-16T04:08:32+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva