audit: allow audit code to satisfy getname requests from its names_list

Currently, if we call getname() on a userland string more than once,
we'll get multiple copies of the string and multiple audit_names
records.

Add a function that will allow the audit_names code to satisfy getname
requests using info from the audit_names list, avoiding a new allocation
and audit_names records.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 11 insertions, 0 deletions

diff --git a/include/linux/audit.h b/include/linux/audit.h
index 94d29164803f..d5d7952ab7d8 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -471,6 +471,7 @@ extern void __audit_syscall_entry(int arch,
                                   int major, unsigned long a0, unsigned long a1,
                                   unsigned long a2, unsigned long a3);
 extern void __audit_syscall_exit(int ret_success, long ret_value);
+extern struct filename *__audit_reusename(const __user char *uptr);
 extern void __audit_getname(struct filename *name);
 extern void audit_putname(struct filename *name);
 extern void __audit_inode(const char *name, const struct dentry *dentry,
@@ -507,6 +508,12 @@ static inline void audit_syscall_exit(void *pt_regs)
                 __audit_syscall_exit(success, return_code);
         }
 }
+static inline struct filename *audit_reusename(const __user char *name)
+{
+        if (unlikely(!audit_dummy_context()))
+                return __audit_reusename(name);
+        return NULL;
+}
 static inline void audit_getname(struct filename *name)
 {
         if (unlikely(!audit_dummy_context()))
@@ -665,6 +672,10 @@ static inline int audit_dummy_context(void)
 {
         return 1;
 }
+static inline struct filename *audit_reusename(const __user char *name)
+{
+        return NULL;
+}
 static inline void audit_getname(struct filename *name)
 { }
 static inline void audit_putname(struct filename *name)