mirror of
https://github.com/torvalds/linux.git
synced 2024-12-31 23:31:29 +00:00
7aa5783d95
System administrators can require that all accessed files have a signature by specifying appraise_type=imasig in a policy rule. Currently, IMA signatures satisfy this requirement. Appended signatures may also satisfy this requirement, but are not applicable as IMA signatures. IMA/appended signatures ensure data source authentication for file content and prevent any change. EVM signatures instead ensure data source authentication for file metadata. Given that the digest or signature of the file content must be included in the metadata, EVM signatures provide the same file data guarantees of IMA signatures, as well as providing file metadata guarantees. This patch lets systems protected with EVM signatures pass appraisal verification if the appraise_type=imasig requirement is specified in the policy. This facilitates deployment in the scenarios where only EVM signatures are available. The patch makes the following changes: file xattr types: security.ima: IMA_XATTR_DIGEST/IMA_XATTR_DIGEST_NG security.evm: EVM_XATTR_PORTABLE_DIGSIG execve(), mmap(), open() behavior (with appraise_type=imasig): before: denied (file without IMA signature, imasig requirement not met) after: allowed (file with EVM portable signature, imasig requirement met) open(O_WRONLY) behavior (without appraise_type=imasig): before: allowed (file without IMA signature, not immutable) after: denied (file with EVM portable signature, immutable) In addition, similarly to IMA signatures, this patch temporarily allows new files without or with incomplete metadata to be opened so that content can be written. Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com> |
||
|---|---|---|
| .. | ||
| ima_api.c | ||
| ima_appraise.c | ||
| ima_asymmetric_keys.c | ||
| ima_crypto.c | ||
| ima_efi.c | ||
| ima_fs.c | ||
| ima_init.c | ||
| ima_kexec.c | ||
| ima_main.c | ||
| ima_modsig.c | ||
| ima_mok.c | ||
| ima_policy.c | ||
| ima_queue_keys.c | ||
| ima_queue.c | ||
| ima_template_lib.c | ||
| ima_template_lib.h | ||
| ima_template.c | ||
| ima.h | ||
| Kconfig | ||
| Makefile | ||