SMACK: Add new lock for adding entry in smack master list
"smk_set_access()" function adds a new rule entry in subject label specific
list(rule_list) and in global rule list(smack_rule_list) both. Mutex lock
(rule_lock) is used to avoid simultaneous updates. But this lock is subject
label specific lock. If 2 processes tries to add different rules(i.e with
different subject labels) simultaneously, then both the processes can take
the "rule_lock" respectively. So it will cause a problem while adding
entries in master rule list.
Now a new mutex lock(smack_master_list_lock) has been taken to add entry in
smack_rule_list to avoid simultaneous updates of different rules.
Signed-off-by: Vishal Goel <vishal.goel@samsung.com>
Signed-off-by: Himanshu Shukla <himanshu.sh@samsung.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 13743a0..366b835 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -67,6 +67,7 @@
/*
* List locks
*/
+static DEFINE_MUTEX(smack_master_list_lock);
static DEFINE_MUTEX(smack_cipso_lock);
static DEFINE_MUTEX(smack_ambient_lock);
static DEFINE_MUTEX(smk_net4addr_lock);
@@ -262,12 +263,16 @@
* it needs to get added for reporting.
*/
if (global) {
+ mutex_unlock(rule_lock);
smlp = kzalloc(sizeof(*smlp), GFP_KERNEL);
if (smlp != NULL) {
smlp->smk_rule = sp;
+ mutex_lock(&smack_master_list_lock);
list_add_rcu(&smlp->list, &smack_rule_list);
+ mutex_unlock(&smack_master_list_lock);
} else
rc = -ENOMEM;
+ return rc;
}
}