diff options
| author | Sang-Heon Jeon <ekffu200098@gmail.com> | 2026-08-24 01:18:14 +0900 |
|---|---|---|
| committer | Julia Lawall <Julia.Lawall@inria.fr> | 2026-08-23 22:12:11 +0200 |
| commit | 2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c (patch) | |
| tree | dcc4da1d99f17541c5590ac63c77da4bf372a4ab /Documentation/ABI/testing/evm | |
| download | linux-stable-2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c.tar.gz linux-stable-2bd30b8dc75b823dd7bbef9d7bc68e1fd7ecee5c.zip | |
coccinelle: alloc_cast: drop removed allocatorsgrafted
- pci_alloc_consistent() and pci_zalloc_consistent() were removed by
commit 7968778914e5
("PCI: Remove the deprecated "pci-dma-compat.h" API")
- kmem_alloc() was removed by commit f078d4ea8276
("xfs: convert kmem_alloc() to kmalloc()")
- kmem_zalloc() was removed by commit 10634530f7ba
("xfs: convert kmem_zalloc() to kzalloc()")
- kmem_zone_alloc() and kmem_zone_zalloc() were removed by commit
bae633a4a283 ("xfs: remove xfs_zone_{alloc,zalloc} helpers")
So drop them from the rules.
No functional change.
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Diffstat (limited to 'Documentation/ABI/testing/evm')
| -rw-r--r-- | Documentation/ABI/testing/evm | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm new file mode 100644 index 000000000..db3007bab --- /dev/null +++ b/Documentation/ABI/testing/evm @@ -0,0 +1,109 @@ +What: /sys/kernel/security/evm +What: /sys/kernel/security/*/evm +Date: March 2011 +Contact: Mimi Zohar <zohar@us.ibm.com> +Description: + EVM protects a file's security extended attributes(xattrs) + against integrity attacks. The initial method maintains an + HMAC-sha1 value across the extended attributes, storing the + value as the extended attribute 'security.evm'. + + EVM supports two classes of security.evm. The first is + an HMAC-sha1 generated locally with a + trusted/encrypted key stored in the Kernel Key + Retention System. The second is a digital signature + generated either locally or remotely using an + asymmetric key. These keys are loaded onto root's + keyring using keyctl, and EVM is then enabled by + echoing a value to <securityfs>/evm made up of the + following bits: + + === ================================================== + Bit Effect + === ================================================== + 0 Enable HMAC validation and creation + 1 Enable digital signature validation + 2 Permit modification of EVM-protected metadata at + runtime. Not supported if HMAC validation and + creation is enabled (deprecated). + 3 Require asymmetric signatures to be version 3 + 31 Disable further runtime modification of EVM policy + === ================================================== + + For example:: + + echo 1 ><securityfs>/evm + + will enable HMAC validation and creation + + :: + + echo 0x80000003 ><securityfs>/evm + + will enable HMAC and digital signature validation and + HMAC creation and disable all further modification of policy. + + :: + + echo 0x80000006 ><securityfs>/evm + + will enable digital signature validation, permit + modification of EVM-protected metadata and + disable all further modification of policy. This option is now + deprecated in favor of:: + + echo 0x80000002 ><securityfs>/evm + + as the outstanding issues that prevent the usage of EVM portable + signatures have been solved. + + Echoing a value is additive, the new value is added to the + existing initialization flags. + + For example, after:: + + echo 2 ><securityfs>/evm + + another echo can be performed:: + + echo 1 ><securityfs>/evm + + and the resulting value will be 3. + + Note that once an HMAC key has been loaded, it will no longer + be possible to enable metadata modification. Signaling that an + HMAC key has been loaded will clear the corresponding flag. + For example, if the current value is 6 (2 and 4 set):: + + echo 1 ><securityfs>/evm + + will set the new value to 3 (4 cleared). + + Loading an HMAC key is the only way to disable metadata + modification. + + Until key loading has been signaled EVM can not create + or validate the 'security.evm' xattr, but returns + INTEGRITY_UNKNOWN. Loading keys 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/security/keys/trusted-encrypted.rst. Both + dracut (via 97masterkey and 98integrity) and systemd (via + core/ima-setup) have support for loading keys at boot + time. + +What: /sys/kernel/security/*/evm/evm_xattrs +Date: April 2018 +Contact: Matthew Garrett <mjg59@google.com> +Description: + Shows the set of extended attributes used to calculate or + validate the EVM signature, and allows additional attributes + to be added at runtime. Any signatures generated after + additional attributes are added (and on files possessing those + additional attributes) will only be valid if the same + additional attributes are configured on system boot. Writing + a single period (.) will lock the xattr list from any further + modification. |
