linux/security/integrity
Roberto Sassu e3ccfe1ad7 evm: Introduce evm_revalidate_status()
When EVM_ALLOW_METADATA_WRITES is set, EVM allows any operation on
metadata. Its main purpose is to allow users to freely set metadata when it
is protected by a portable signature, until an HMAC key is loaded.

However, callers of evm_verifyxattr() are not notified about metadata
changes and continue to rely on the last status returned by the function.
For example IMA, since it caches the appraisal result, will not call again
evm_verifyxattr() until the appraisal flags are cleared, and will grant
access to the file even if there was a metadata operation that made the
portable signature invalid.

This patch introduces evm_revalidate_status(), which callers of
evm_verifyxattr() can use in their xattr hooks to determine whether
re-validation is necessary and to do the proper actions. IMA calls it in
its xattr hooks to reset the appraisal flags, so that the EVM status is
re-evaluated after a metadata operation.

Lastly, this patch also adds a call to evm_reset_status() in
evm_inode_post_setattr() to invalidate the cached EVM status after a
setattr operation.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-05-21 12:47:12 -04:00
..
evm evm: Introduce evm_revalidate_status() 2021-05-21 12:47:12 -04:00
ima evm: Introduce evm_revalidate_status() 2021-05-21 12:47:12 -04:00
platform_certs integrity: Load mokx variables into the blacklist keyring 2021-03-11 16:34:48 +00:00
digsig_asymmetric.c ima: Support EC keys for signature verification 2021-03-26 19:41:59 +11:00
digsig.c ima: enable loading of build time generated key on .ima keyring 2021-04-09 10:40:20 -04:00
iint.c evm: Load EVM key in ima_load_x509() to avoid appraisal 2021-05-21 12:47:04 -04:00
integrity_audit.c integrity: Use current_uid() in integrity_audit_message() 2020-08-31 17:46:50 -04:00
integrity.h crypto: sha - split sha.h into sha1.h and sha2.h 2020-11-20 14:45:33 +11:00
Kconfig powerpc: Load firmware trusted keys/hashes into kernel keyring 2019-11-13 00:33:23 +11:00
Makefile powerpc: Load firmware trusted keys/hashes into kernel keyring 2019-11-13 00:33:23 +11:00