ima: require signature based appraisal

This patch provides CONFIG_IMA_APPRAISE_SIGNED_INIT kernel configuration
option to force IMA appraisal using signatures. This is useful, when EVM
key is not initialized yet and we want securely initialize integrity or
any other functionality.

It forces embedded policy to require signature. Signed initialization
script can initialize EVM key, update the IMA policy and change further
requirement of everything to be signed.

Changes in v3:
* kernel parameter fixed to configuration option in the patch description

Changes in v2:
* policy change of this patch separated from the key loading patch

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
This commit is contained in:
Dmitry Kasatkin 2014-11-05 17:01:16 +02:00 committed by Mimi Zohar
parent c9cd2ce2bc
commit c57782c13e
2 changed files with 13 additions and 0 deletions

View File

@ -149,3 +149,10 @@ config IMA_X509_PATH
default "/etc/keys/x509_ima.der"
help
This option defines IMA X509 certificate path.
config IMA_APPRAISE_SIGNED_INIT
bool "Require signed user-space initialization"
depends on IMA_LOAD_X509
default n
help
This option requires user-space init to be signed.

View File

@ -100,7 +100,13 @@ static struct ima_rule_entry default_appraise_rules[] = {
{.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
{.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
#ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
#else
/* force signature */
{.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
.flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
#endif
};
static LIST_HEAD(ima_default_rules);