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ima: limit imbalance msg

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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>
This commit is contained in:
Mimi Zohar 2009-12-04 15:48:40 -05:00 committed by Al Viro
parent 1429b3eca2
commit d1625436b4
1 changed files with 53 additions and 9 deletions
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62
security/integrity/ima/ima_main.c
View file

@ -35,6 +35,55 @@ static int __init hash_setup(char *str)
}
__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 @@ static void ima_dec_counts(struct ima_iint_cache *iint, struct inode *inode,
}
}
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);