From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60F73C07EBE for ; Tue, 26 Jan 2021 19:13:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BA3122A84 for ; Tue, 26 Jan 2021 19:13:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726587AbhAZFy0 convert rfc822-to-8bit (ORCPT ); Tue, 26 Jan 2021 00:54:26 -0500 Received: from mx2.suse.de ([195.135.220.15]:48252 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727389AbhAYKQJ (ORCPT ); Mon, 25 Jan 2021 05:16:09 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 18B10AD8C; Mon, 25 Jan 2021 10:13:57 +0000 (UTC) Received: from localhost (brahms [local]) by brahms (OpenSMTPD) with ESMTPA id 2dfa81f0; Mon, 25 Jan 2021 10:14:49 +0000 (UTC) From: Luis Henriques To: Jeff Layton Cc: ceph-devel@vger.kernel.org, linux-fscrypt@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH v4 08/17] ceph: add routine to create fscrypt context prior to RPC References: <20210120182847.644850-1-jlayton@kernel.org> <20210120182847.644850-9-jlayton@kernel.org> <87tur8532c.fsf@suse.de> Date: Mon, 25 Jan 2021 10:14:49 +0000 In-Reply-To: (Jeff Layton's message of "Fri, 22 Jan 2021 12:32:56 -0500") Message-ID: <87zh0xuxuu.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Jeff Layton writes: > On Fri, 2021-01-22 at 16:50 +0000, Luis Henriques wrote: >> Jeff Layton writes: >> >> > After pre-creating a new inode, do an fscrypt prepare on it, fetch a >> > new encryption context and then marshal that into the security context >> > to be sent along with the RPC. >> > >> > Signed-off-by: Jeff Layton >> > --- >> >  fs/ceph/crypto.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++ >> >  fs/ceph/crypto.h | 12 ++++++++++ >> >  fs/ceph/inode.c | 9 +++++-- >> >  fs/ceph/super.h | 3 +++ >> >  4 files changed, 83 insertions(+), 2 deletions(-) >> > >> > diff --git a/fs/ceph/crypto.c b/fs/ceph/crypto.c >> > index 879d9a0d3751..f037a4939026 100644 >> > --- a/fs/ceph/crypto.c >> > +++ b/fs/ceph/crypto.c >> > @@ -46,3 +46,64 @@ void ceph_fscrypt_set_ops(struct super_block *sb) >> >  { >> >   fscrypt_set_ops(sb, &ceph_fscrypt_ops); >> >  } >> > + >> > +int ceph_fscrypt_prepare_context(struct inode *dir, struct inode *inode, >> > + struct ceph_acl_sec_ctx *as) >> > +{ >> > + int ret, ctxsize; >> > + size_t name_len; >> > + char *name; >> > + struct ceph_pagelist *pagelist = as->pagelist; >> > + bool encrypted = false; >> > + >> > + ret = fscrypt_prepare_new_inode(dir, inode, &encrypted); >> > + if (ret) >> > + return ret; >> > + if (!encrypted) >> > + return 0; >> > + >> > + inode->i_flags |= S_ENCRYPTED; >> > + >> > + ctxsize = fscrypt_context_for_new_inode(&as->fscrypt, inode); >> > + if (ctxsize < 0) >> > + return ctxsize; >> > + >> > + /* marshal it in page array */ >> > + if (!pagelist) { >> > + pagelist = ceph_pagelist_alloc(GFP_KERNEL); >> > + if (!pagelist) >> > + return -ENOMEM; >> > + ret = ceph_pagelist_reserve(pagelist, PAGE_SIZE); >> > + if (ret) >> > + goto out; >> > + ceph_pagelist_encode_32(pagelist, 1); >> > + } >> > + >> > + name = CEPH_XATTR_NAME_ENCRYPTION_CONTEXT; >> > + name_len = strlen(name); >> > + ret = ceph_pagelist_reserve(pagelist, 4 * 2 + name_len + ctxsize); >> > + if (ret) >> > + goto out; >> > + >> > + if (as->pagelist) { >> > + BUG_ON(pagelist->length <= sizeof(__le32)); >> > + if (list_is_singular(&pagelist->head)) { >> > + le32_add_cpu((__le32*)pagelist->mapped_tail, 1); >> > + } else { >> > + struct page *page = list_first_entry(&pagelist->head, >> > + struct page, lru); >> > + void *addr = kmap_atomic(page); >> > + le32_add_cpu((__le32*)addr, 1); >> > + kunmap_atomic(addr); >> > + } >> > + } >> > + >> >> I've been staring at this function for a bit. And at this point I would >> expect something like this: >> >> } else >> as->pagelist = pagelist; >> >> as I'm not seeing pagelist being used anywhere if it's allocated in this >> function. >> > > It gets used near the end, in the ceph_pagelist_append calls. Once we've > appended the xattr, we don't need the pagelist anymore and can free it. Doh! Sorry for the noise ;-) Cheers, -- Luis > That said, the whole way the ceph_pagelist stuff is managed is weird. > I'm not clear why it was done that way, and maybe we ought to rework > this, SELinux and ACL handling to not use them. > > I think that's a cleanup for another day. > -- > Jeff Layton >