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ima: fallback to MODULE_SIG_ENFORCE for existing kernel module syscall

The new kernel module syscall appraises kernel modules based
on policy.   If the IMA policy requires kernel module checking,
fallback to module signature enforcing for the existing syscall.
Without CONFIG_MODULE_SIG_FORCE enabled, the kernel module's
integrity is unknown, return -EACCES.

Changelog v1:
- Fix ima_module_check() return result (Tetsuo Handa)

Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
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1 parent a49f0d1 commit a7f2a366f62319dfebf8d4dfe8b211f631c78457 Mimi Zohar committed Dec 21, 2012
Showing with 11 additions and 5 deletions.
  1. +1 −0 security/integrity/ima/ima.h
  2. +8 −4 security/integrity/ima/ima_main.c
  3. +2 −1 security/integrity/ima/ima_policy.c
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1 security/integrity/ima/ima.h
@@ -139,6 +139,7 @@ void ima_delete_rules(void);
/* Appraise integrity measurements */
#define IMA_APPRAISE_ENFORCE 0x01
#define IMA_APPRAISE_FIX 0x02
+#define IMA_APPRAISE_MODULES 0x04
#ifdef CONFIG_IMA_APPRAISE
int ima_appraise_measurement(struct integrity_iint_cache *iint,
View
12 security/integrity/ima/ima_main.c
@@ -291,11 +291,15 @@ EXPORT_SYMBOL_GPL(ima_file_check);
*/
int ima_module_check(struct file *file)
{
- int rc;
+ int rc = 0;
- if (!file)
- rc = INTEGRITY_UNKNOWN;
- else
+ if (!file) {
+ if (ima_appraise & IMA_APPRAISE_MODULES) {
+#ifndef CONFIG_MODULE_SIG_FORCE
+ rc = -EACCES; /* INTEGRITY_UNKNOWN */
+#endif
+ }
+ } else
rc = process_measurement(file, file->f_dentry->d_name.name,
MAY_EXEC, MODULE_CHECK);
return (ima_appraise & IMA_APPRAISE_ENFORCE) ? rc : 0;
View
3 security/integrity/ima/ima_policy.c
@@ -523,7 +523,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
}
if (!result && (entry->action == UNKNOWN))
result = -EINVAL;
-
+ else if (entry->func == MODULE_CHECK)
+ ima_appraise |= IMA_APPRAISE_MODULES;
audit_log_format(ab, "res=%d", !result);
audit_log_end(ab);
return result;

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