Permit normally denied access/execute permission for files in policy
on IMA unsupported filesystems. This patch defines "fs_unsafe", a
builtin policy.
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
---
Changelog v3:
- include dont_failsafe rule when displaying policy
Documentation/admin-guide/kernel-parameters.txt | 8 +++++++-
security/integrity/ima/ima_policy.c | 12 ++++++++++++
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9c171ce4190..4e303be83df6 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1502,7 +1502,7 @@
ima_policy= [IMA]
The builtin policies to load during IMA setup.
- Format: "tcb | appraise_tcb | secure_boot"
+ Format: "tcb | appraise_tcb | secure_boot | fs_unsafe"
The "tcb" policy measures all programs exec'd, files
mmap'd for exec, and all files opened with the read
@@ -1517,6 +1517,12 @@
of files (eg. kexec kernel image, kernel modules,
firmware, policy, etc) based on file signatures.
+ The "fs_unsafe" policy permits normally denied
+ access/execute permission for files in policy on IMA
+ unsupported filesystems. Note this option, as the
+ name implies, is not safe and not recommended for
+ any environments other than testing.
+
ima_tcb [IMA] Deprecated. Use ima_policy= instead.
Load a policy which meets the needs of the Trusted
Computing Base. This means IMA will measure all
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 43b85a4fb8e8..cddd9dfb01e1 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -169,6 +169,10 @@ static struct ima_rule_entry secure_boot_rules[] __ro_after_init = {
.flags = IMA_FUNC | IMA_DIGSIG_REQUIRED},
};
+static struct ima_rule_entry dont_failsafe_rules[] __ro_after_init = {
+ {.action = DONT_FAILSAFE}
+};
+
static LIST_HEAD(ima_default_rules);
static LIST_HEAD(ima_policy_rules);
static LIST_HEAD(ima_temp_rules);
@@ -188,6 +192,7 @@ __setup("ima_tcb", default_measure_policy_setup);
static bool ima_use_appraise_tcb __initdata;
static bool ima_use_secure_boot __initdata;
+static bool ima_use_dont_failsafe __initdata;
static int __init policy_setup(char *str)
{
char *p;
@@ -201,6 +206,10 @@ static int __init policy_setup(char *str)
ima_use_appraise_tcb = 1;
else if (strcmp(p, "secure_boot") == 0)
ima_use_secure_boot = 1;
+ else if (strcmp(p, "fs_unsafe") == 0) {
+ ima_use_dont_failsafe = 1;
+ set_failsafe(0);
+ }
}
return 1;
@@ -470,6 +479,9 @@ void __init ima_init_policy(void)
temp_ima_appraise |= IMA_APPRAISE_POLICY;
}
+ if (ima_use_dont_failsafe)
+ list_add_tail(&dont_failsafe_rules[0].list, &ima_default_rules);
+
ima_rules = &ima_default_rules;
ima_update_policy_flag();
}
--
2.7.4
