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>
diff --git a/fs/namei.c b/fs/namei.c
index ec638d2..5dbc3f83 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -130,6 +130,10 @@
char *kname;
int len;
+ result = audit_reusename(filename);
+ if (result)
+ return result;
+
/* FIXME: create dedicated slabcache? */
result = kzalloc(sizeof(*result), GFP_KERNEL);
if (unlikely(!result))
diff --git a/include/linux/audit.h b/include/linux/audit.h
index 94d2916..d5d7952 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -471,6 +471,7 @@
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 @@
__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 @@
{
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)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d4d8231..521163a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2021,6 +2021,29 @@
}
/**
+ * audit_reusename - fill out filename with info from existing entry
+ * @uptr: userland ptr to pathname
+ *
+ * Search the audit_names list for the current audit context. If there is an
+ * existing entry with a matching "uptr" then return the filename
+ * associated with that audit_name. If not, return NULL.
+ */
+struct filename *
+__audit_reusename(const __user char *uptr)
+{
+ struct audit_context *context = current->audit_context;
+ struct audit_names *n;
+
+ list_for_each_entry(n, &context->names_list, list) {
+ if (!n->name)
+ continue;
+ if (n->name->uptr == uptr)
+ return n->name;
+ }
+ return NULL;
+}
+
+/**
* audit_getname - add a name to the list
* @name: name to add
*
