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Diffstat (limited to 'security/smack/smack_access.c')
-rw-r--r--security/smack/smack_access.c54
1 files changed, 41 insertions, 13 deletions
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 42becbc1ce33..7ba8478f599e 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -67,6 +67,46 @@ static u32 smack_next_secid = 10;
int log_policy = SMACK_AUDIT_DENIED;
/**
+ * smk_access_entry - look up matching access rule
+ * @subject_label: a pointer to the subject's Smack label
+ * @object_label: a pointer to the object's Smack label
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns pointer to the matching rule if found,
+ * NULL otherwise.
+ *
+ * NOTE:
+ * Even though Smack labels are usually shared on smack_list
+ * labels that come in off the network can't be imported
+ * and added to the list for locking reasons.
+ *
+ * Therefore, it is necessary to check the contents of the labels,
+ * not just the pointer values. Of course, in most cases the labels
+ * will be on the list, so checking the pointers may be a worthwhile
+ * optimization.
+ */
+int smk_access_entry(char *subject_label, char *object_label)
+{
+ u32 may = MAY_NOT;
+ struct smack_rule *srp;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(srp, &smack_rule_list, list) {
+ if (srp->smk_subject == subject_label ||
+ strcmp(srp->smk_subject, subject_label) == 0) {
+ if (srp->smk_object == object_label ||
+ strcmp(srp->smk_object, object_label) == 0) {
+ may = srp->smk_access;
+ break;
+ }
+ }
+ }
+ rcu_read_unlock();
+
+ return may;
+}
+
+/**
* smk_access - determine if a subject has a specific access to an object
* @subject_label: a pointer to the subject's Smack label
* @object_label: a pointer to the object's Smack label
@@ -90,7 +130,6 @@ int smk_access(char *subject_label, char *object_label, int request,
struct smk_audit_info *a)
{
u32 may = MAY_NOT;
- struct smack_rule *srp;
int rc = 0;
/*
@@ -144,18 +183,7 @@ int smk_access(char *subject_label, char *object_label, int request,
* access (e.g. read is included in readwrite) it's
* good.
*/
- rcu_read_lock();
- list_for_each_entry_rcu(srp, &smack_rule_list, list) {
- if (srp->smk_subject == subject_label ||
- strcmp(srp->smk_subject, subject_label) == 0) {
- if (srp->smk_object == object_label ||
- strcmp(srp->smk_object, object_label) == 0) {
- may = srp->smk_access;
- break;
- }
- }
- }
- rcu_read_unlock();
+ may = smk_access_entry(subject_label, object_label);
/*
* This is a bit map operation.
*/