selinux: Implementation for inode_copy_up_xattr() hook

When a file is copied up in overlay, we have already created file on
upper/ with right label and there is no need to copy up selinux
label/xattr from lower file to upper file. In fact in case of context
mount, we don't want to copy up label as newly created file got its label
from context= option.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This commit is contained in:
Vivek Goyal 2016-07-13 10:44:50 -04:00 committed by Paul Moore
parent 121ab822ef
commit 19472b69d6

View File

@ -3313,6 +3313,21 @@ static int selinux_inode_copy_up(struct dentry *src, struct cred **new)
return 0;
}
static int selinux_inode_copy_up_xattr(const char *name)
{
/* The copy_up hook above sets the initial context on an inode, but we
* don't then want to overwrite it by blindly copying all the lower
* xattrs up. Instead, we have to filter out SELinux-related xattrs.
*/
if (strcmp(name, XATTR_NAME_SELINUX) == 0)
return 1; /* Discard */
/*
* Any other attribute apart from SELINUX is not claimed, supported
* by selinux.
*/
return -EOPNOTSUPP;
}
/* file security operations */
static int selinux_revalidate_file_permission(struct file *file, int mask)
@ -6109,6 +6124,7 @@ static struct security_hook_list selinux_hooks[] = {
LSM_HOOK_INIT(inode_listsecurity, selinux_inode_listsecurity),
LSM_HOOK_INIT(inode_getsecid, selinux_inode_getsecid),
LSM_HOOK_INIT(inode_copy_up, selinux_inode_copy_up),
LSM_HOOK_INIT(inode_copy_up_xattr, selinux_inode_copy_up_xattr),
LSM_HOOK_INIT(file_permission, selinux_file_permission),
LSM_HOOK_INIT(file_alloc_security, selinux_file_alloc_security),