integrity: IMA policy open

Sequentialize access to the policy file
- permit multiple attempts to replace default policy with a valid policy

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
Mimi Zohar 2009-02-04 09:07:01 -05:00 committed by James Morris
parent 4af4662fa4
commit f4bd857bc8

View file

@ -277,16 +277,30 @@ static struct dentry *runtime_measurements_count;
static struct dentry *violations;
static struct dentry *ima_policy;
static atomic_t policy_opencount = ATOMIC_INIT(1);
/*
* ima_open_policy: sequentialize access to the policy file
*/
int ima_open_policy(struct inode * inode, struct file * filp)
{
if (atomic_dec_and_test(&policy_opencount))
return 0;
return -EBUSY;
}
/*
* ima_release_policy - start using the new measure policy rules.
*
* Initially, ima_measure points to the default policy rules, now
* point to the new policy rules, and remove the securityfs policy file.
* point to the new policy rules, and remove the securityfs policy file,
* assuming a valid policy.
*/
static int ima_release_policy(struct inode *inode, struct file *file)
{
if (!valid_policy) {
ima_delete_rules();
valid_policy = 1;
atomic_set(&policy_opencount, 1);
return 0;
}
ima_update_policy();
@ -296,6 +310,7 @@ static int ima_release_policy(struct inode *inode, struct file *file)
}
static struct file_operations ima_measure_policy_ops = {
.open = ima_open_policy,
.write = ima_write_policy,
.release = ima_release_policy
};