===================================================================
@@ -410,6 +410,14 @@
* @src indicates the union dentry of file that is being copied up.
* @new pointer to pointer to return newly allocated creds.
* Returns 0 on success or a negative error code on error.
+ * @inode_copy_up_xattr:
+ * Filter the xattrs being copied up when a unioned file is copied
+ * up from a lower layer to the union/overlay layer.
+ * @name indicates the name of the xattr.
+ * Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP if
+ * security module does not know about attribute or a negative error code
+ * to abort the copy up. Note that the caller is responsible for reading
+ * and writing the xattrs as this hook is merely a filter.
*
* Security hooks for file operations
*
@@ -1435,6 +1443,7 @@ union security_list_options {
size_t buffer_size);
void (*inode_getsecid)(struct inode *inode, u32 *secid);
int (*inode_copy_up) (struct dentry *src, struct cred **new);
+ int (*inode_copy_up_xattr) (const char *name);
int (*file_permission)(struct file *file, int mask);
int (*file_alloc_security)(struct file *file);
@@ -1707,6 +1716,7 @@ struct security_hook_heads {
struct list_head inode_listsecurity;
struct list_head inode_getsecid;
struct list_head inode_copy_up;
+ struct list_head inode_copy_up_xattr;
struct list_head file_permission;
struct list_head file_alloc_security;
struct list_head file_free_security;
===================================================================
@@ -283,6 +283,7 @@ int security_inode_setsecurity(struct in
int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
void security_inode_getsecid(struct inode *inode, u32 *secid);
int security_inode_copy_up(struct dentry *src, struct cred **new);
+int security_inode_copy_up_xattr(const char *name);
int security_file_permission(struct file *file, int mask);
int security_file_alloc(struct file *file);
void security_file_free(struct file *file);
@@ -764,6 +765,11 @@ static inline int security_inode_copy_up
return 0;
}
+static inline int security_inode_copy_up_xattr(const char *name)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int security_file_permission(struct file *file, int mask)
{
return 0;
===================================================================
@@ -733,6 +733,12 @@ int security_inode_copy_up(struct dentry
}
EXPORT_SYMBOL(security_inode_copy_up);
+int security_inode_copy_up_xattr(const char *name)
+{
+ return call_int_hook(inode_copy_up_xattr, -EOPNOTSUPP, name);
+}
+EXPORT_SYMBOL(security_inode_copy_up_xattr);
+
int security_file_permission(struct file *file, int mask)
{
int ret;
@@ -1671,6 +1677,8 @@ struct security_hook_heads security_hook
LIST_HEAD_INIT(security_hook_heads.inode_getsecid),
.inode_copy_up =
LIST_HEAD_INIT(security_hook_heads.inode_copy_up),
+ .inode_copy_up_xattr =
+ LIST_HEAD_INIT(security_hook_heads.inode_copy_up_xattr),
.file_permission =
LIST_HEAD_INIT(security_hook_heads.file_permission),
.file_alloc_security =
===================================================================
@@ -103,6 +103,13 @@ retry:
goto retry;
}
+ error = security_inode_copy_up_xattr(name);
+ if (error < 0 && error != -EOPNOTSUPP)
+ break;
+ if (error == 1) {
+ error = 0;
+ continue; /* Discard */
+ }
error = vfs_setxattr(new, name, value, size, 0);
if (error)
break;