[PATCH v4 18/19] ima: measure and appraise the IMA policy itself
Mimi Zohar
zohar at linux.vnet.ibm.com
Fri Feb 12 10:29:30 PST 2016
Add support for measuring and appraising the IMA policy itself.
Changelog v4:
- use braces on both if/else branches, even if single line on one of the
branches - Dmitry
- Use the id mapping - Dmitry
Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>
Acked-by: Petko Manolov <petkan at mip-labs.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin at huawei.com>
---
security/integrity/ima/ima.h | 2 ++
security/integrity/ima/ima_fs.c | 12 ++++++++++--
security/integrity/ima/ima_main.c | 1 +
security/integrity/ima/ima_policy.c | 11 ++++++++++-
4 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index bd97e0d..5d0f611 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -149,6 +149,7 @@ enum ima_hooks {
FIRMWARE_CHECK,
KEXEC_KERNEL_CHECK,
KEXEC_INITRAMFS_CHECK,
+ POLICY_CHECK,
MAX_CHECK
};
@@ -191,6 +192,7 @@ int ima_policy_show(struct seq_file *m, void *v);
#define IMA_APPRAISE_LOG 0x04
#define IMA_APPRAISE_MODULES 0x08
#define IMA_APPRAISE_FIRMWARE 0x10
+#define IMA_APPRAISE_POLICY 0x20
#ifdef CONFIG_IMA_APPRAISE
int ima_appraise_measurement(enum ima_hooks func,
diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
index 57989a4..9f8cb10 100644
--- a/security/integrity/ima/ima_fs.c
+++ b/security/integrity/ima/ima_fs.c
@@ -323,10 +323,18 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
if (result < 0)
goto out_free;
- if (data[0] == '/')
+ if (data[0] == '/') {
result = ima_read_policy(data);
- else
+ } else if (ima_appraise & IMA_APPRAISE_POLICY) {
+ pr_err("IMA: signed policy file (specified as an absolute pathname) required\n");
+ integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
+ "policy_update", "signed policy required",
+ 1, 0);
+ if (ima_appraise & IMA_APPRAISE_ENFORCE)
+ result = -EACCES;
+ } else {
result = ima_parse_add_rule(data);
+ }
mutex_unlock(&ima_write_mutex);
out_free:
kfree(data);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 4d0bdf1..b14c1c1 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -344,6 +344,7 @@ static int read_idmap[READING_MAX_ID] = {
[READING_MODULE] = MODULE_CHECK,
[READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
[READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
+ [READING_POLICY] = POLICY_CHECK
};
/**
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5ccd3f5..77a9fee 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -114,6 +114,7 @@ static struct ima_rule_entry default_measurement_rules[] = {
.uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
{.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
{.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
+ {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
};
static struct ima_rule_entry default_appraise_rules[] = {
@@ -618,6 +619,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK")
== 0)
entry->func = KEXEC_INITRAMFS_CHECK;
+ else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
+ entry->func = POLICY_CHECK;
else
result = -EINVAL;
if (!result)
@@ -776,6 +779,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
temp_ima_appraise |= IMA_APPRAISE_MODULES;
else if (entry->func == FIRMWARE_CHECK)
temp_ima_appraise |= IMA_APPRAISE_FIRMWARE;
+ else if (entry->func == POLICY_CHECK)
+ temp_ima_appraise |= IMA_APPRAISE_POLICY;
audit_log_format(ab, "res=%d", !result);
audit_log_end(ab);
return result;
@@ -862,7 +867,8 @@ static char *mask_tokens[] = {
enum {
func_file = 0, func_mmap, func_bprm,
func_module, func_firmware, func_post,
- func_kexec_kernel, func_kexec_initramfs
+ func_kexec_kernel, func_kexec_initramfs,
+ func_policy
};
static char *func_tokens[] = {
@@ -942,6 +948,9 @@ static void policy_func_show(struct seq_file *m, enum ima_hooks func)
case KEXEC_INITRAMFS_CHECK:
seq_printf(m, pt(Opt_func), ft(func_kexec_initramfs));
break;
+ case POLICY_CHECK:
+ seq_printf(m, pt(Opt_func), ft(func_policy));
+ break;
default:
snprintf(tbuf, sizeof(tbuf), "%d", func);
seq_printf(m, pt(Opt_func), tbuf);
--
2.1.0
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