[PATCH] mark context of syscall entered with no rules as dummy

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 10 insertions, 2 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index f1bfcff497bf..3f736d658218 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -329,6 +329,11 @@ extern void __audit_inode(const char *name, const struct inode *inode);
 extern void __audit_inode_child(const char *dname, const struct inode *inode,
                                 const struct inode *parent);
 extern void __audit_inode_update(const struct inode *inode);
+static inline int audit_dummy_context(void)
+{
+        void *p = current->audit_context;
+        return !p || *(int *)p;
+}
 static inline void audit_getname(const char *name)
 {
         if (unlikely(current->audit_context))
@@ -416,6 +421,7 @@ extern int audit_n_rules;
 #define audit_free(t) do { ; } while (0)
 #define audit_syscall_entry(ta,a,b,c,d,e) do { ; } while (0)
 #define audit_syscall_exit(f,r) do { ; } while (0)
+#define audit_dummy_context() 1
 #define audit_getname(n) do { ; } while (0)
 #define audit_putname(n) do { ; } while (0)
 #define __audit_inode(n,i) do { ; } while (0)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3ea836d3d941..9618d1507251 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -177,6 +177,7 @@ struct audit_aux_data_path {
 
 /* The per-task audit context. */
 struct audit_context {
+        int                 dummy;      /* must be the first element */
         int                 in_syscall; /* 1 if task is in a syscall */
         enum audit_state    state;
         unsigned int        serial;     /* serial number for record */
@@ -517,7 +518,7 @@ static inline struct audit_context *audit_get_context(struct task_struct *tsk,
         context->return_valid = return_valid;
         context->return_code  = return_code;
 
-        if (context->in_syscall && !context->auditable) {
+        if (context->in_syscall && !context->dummy && !context->auditable) {
                 enum audit_state state;
 
                 state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_EXIT]);
@@ -1069,7 +1070,8 @@ void audit_syscall_entry(int arch, int major,
         context->argv[3]    = a4;
 
         state = context->state;
-        if (state == AUDIT_SETUP_CONTEXT || state == AUDIT_BUILD_CONTEXT)
+        context->dummy = !audit_n_rules;
+        if (!context->dummy && (state == AUDIT_SETUP_CONTEXT || state == AUDIT_BUILD_CONTEXT))
                 state = audit_filter_syscall(tsk, context, &audit_filter_list[AUDIT_FILTER_ENTRY]);
         if (likely(state == AUDIT_DISABLED))
                 return;