security,overlayfs: Provide security hook for copy up of xattrs for overlay file

Provide a security hook which is called when xattrs of a file are being
copied up. This hook is called once for each xattr and LSM can return
0 if the security module wants the xattr to be copied up, 1 if the
security module wants the xattr to be discarded on the copy, -EOPNOTSUPP
if the security module does not handle/manage the xattr, or a -errno
upon an error.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
[PM: whitespace cleanup for checkpatch.pl]
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Vivek Goyal
2016-07-13 10:44:49 -04:00
committed by Paul Moore
parent 56909eb3f5
commit 121ab822ef
4 changed files with 31 additions and 0 deletions

View File

@@ -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;