ima: limit imbalance msg
Limit the number of imbalance messages to once per filesystem type instead of
once per system boot. (it's actually slightly racy and could give you a
couple per fs, but this isn't a real issue)
Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 16dc57d..a89f44d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -35,6 +35,55 @@
}
__setup("ima_hash=", hash_setup);
+struct ima_imbalance {
+ struct hlist_node node;
+ unsigned long fsmagic;
+};
+
+/*
+ * ima_limit_imbalance - emit one imbalance message per filesystem type
+ *
+ * Maintain list of filesystem types that do not measure files properly.
+ * Return false if unknown, true if known.
+ */
+static bool ima_limit_imbalance(struct file *file)
+{
+ static DEFINE_SPINLOCK(ima_imbalance_lock);
+ static HLIST_HEAD(ima_imbalance_list);
+
+ struct super_block *sb = file->f_dentry->d_sb;
+ struct ima_imbalance *entry;
+ struct hlist_node *node;
+ bool found = false;
+
+ rcu_read_lock();
+ hlist_for_each_entry_rcu(entry, node, &ima_imbalance_list, node) {
+ if (entry->fsmagic == sb->s_magic) {
+ found = true;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ if (found)
+ goto out;
+
+ entry = kmalloc(sizeof(*entry), GFP_NOFS);
+ if (!entry)
+ goto out;
+ entry->fsmagic = sb->s_magic;
+ spin_lock(&ima_imbalance_lock);
+ /*
+ * we could have raced and something else might have added this fs
+ * to the list, but we don't really care
+ */
+ hlist_add_head_rcu(&entry->node, &ima_imbalance_list);
+ spin_unlock(&ima_imbalance_lock);
+ printk(KERN_INFO "IMA: unmeasured files on fsmagic: %lX\n",
+ entry->fsmagic);
+out:
+ return found;
+}
+
/*
* Update the counts given an fmode_t
*/
@@ -69,15 +118,10 @@
}
}
- if ((iint->opencount < 0) ||
- (iint->readcount < 0) ||
- (iint->writecount < 0)) {
- static int dumped;
-
- if (dumped)
- return;
- dumped = 1;
-
+ if (((iint->opencount < 0) ||
+ (iint->readcount < 0) ||
+ (iint->writecount < 0)) &&
+ !ima_limit_imbalance(file)) {
printk(KERN_INFO "%s: open/free imbalance (r:%ld w:%ld o:%ld)\n",
__FUNCTION__, iint->readcount, iint->writecount,
iint->opencount);
