From c57782c13ecd7e7aca66cbf0139ad2a72317dc81 Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Wed, 5 Nov 2014 17:01:16 +0200 Subject: 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 Signed-off-by: Mimi Zohar --- security/integrity/ima/Kconfig | 7 +++++++ security/integrity/ima/ima_policy.c | 6 ++++++ 2 files changed, 13 insertions(+) (limited to 'security/integrity') diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig index b0840f9a552f..b80a93ec1ccc 100644 --- a/security/integrity/ima/Kconfig +++ b/security/integrity/ima/Kconfig @@ -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. diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 0d14d2591805..d1eefb9d65fb 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -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); -- cgit v1.2.3-59-g8ed1b