When checking permissions on an overlayfs inode we do not take into account either device cgroup restrictions nor security permissions. This allows a user to mount an overlayfs layer over a restricted device directory and by pass those permissions to open otherwise restricted files. Switch over to the newly introduced inode_only_permissions. Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxxx> --- fs/overlayfs/inode.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index ba1a777..bc9178c 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -105,19 +105,9 @@ int ovl_permission(struct inode *inode, int mask) if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) && (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) goto out_dput; - - /* - * Nobody gets write access to an immutable file. - */ - err = -EACCES; - if (IS_IMMUTABLE(realinode)) - goto out_dput; } - if (realinode->i_op->permission) - err = realinode->i_op->permission(realinode, mask); - else - err = generic_permission(realinode, mask); + err = inode_only_permission(realinode, mask); out_dput: dput(alias); return err; -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
