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Diffstat (limited to 'Documentation/ABI/testing/evm')
| -rw-r--r-- | Documentation/ABI/testing/evm | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm new file mode 100644 index 000000000..8374d4557 --- /dev/null +++ b/Documentation/ABI/testing/evm @@ -0,0 +1,23 @@ +What: 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 depends on the Kernel Key Retention System to provide it + with a trusted/encrypted key for the HMAC-sha1 operation. + The key is loaded onto the root's keyring using keyctl. Until + EVM receives notification that the key has been successfully + loaded onto the keyring (echo 1 > <securityfs>/evm), EVM + can not create or validate the 'security.evm' xattr, but + returns INTEGRITY_UNKNOWN. Loading the key 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/keys-trusted-encrypted.txt. (A sample dracut + patch, which loads the trusted/encrypted key and enables + EVM, is available from http://linux-ima.sourceforge.net/#EVM.) |