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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5DABEE8181A for ; Tue, 26 Sep 2023 11:15:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230380AbjIZLPK convert rfc822-to-8bit (ORCPT ); Tue, 26 Sep 2023 07:15:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47684 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbjIZLPJ (ORCPT ); Tue, 26 Sep 2023 07:15:09 -0400 Received: from frasgout12.his.huawei.com (frasgout12.his.huawei.com [14.137.139.154]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E72EDE5; Tue, 26 Sep 2023 04:15:01 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.18.147.228]) by frasgout12.his.huawei.com (SkyGuard) with ESMTP id 4RvxbH6zKSz9v7cV; Tue, 26 Sep 2023 18:59:55 +0800 (CST) Received: from [127.0.0.1] (unknown [10.204.63.22]) by APP1 (Coremail) with SMTP id LxC2BwDHH5ELvRJlT9ARAQ--.20978S2; Tue, 26 Sep 2023 12:14:32 +0100 (CET) Message-ID: <66249824469de1edefd42b42f72cab17ea331d09.camel@huaweicloud.com> Subject: Re: [PATCH v3 12/25] security: Introduce inode_post_setattr hook From: Roberto Sassu To: viro@zeniv.linux.org.uk, brauner@kernel.org, chuck.lever@oracle.com, jlayton@kernel.org, neilb@suse.de, kolga@netapp.com, Dai.Ngo@oracle.com, tom@talpey.com, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, dhowells@redhat.com, jarkko@kernel.org, stephen.smalley.work@gmail.com, eparis@parisplace.org, casey@schaufler-ca.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, selinux@vger.kernel.org, Roberto Sassu Date: Tue, 26 Sep 2023 13:14:17 +0200 In-Reply-To: <20230904133415.1799503-13-roberto.sassu@huaweicloud.com> References: <20230904133415.1799503-1-roberto.sassu@huaweicloud.com> <20230904133415.1799503-13-roberto.sassu@huaweicloud.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.44.4-0ubuntu2 MIME-Version: 1.0 X-CM-TRANSID: LxC2BwDHH5ELvRJlT9ARAQ--.20978S2 X-Coremail-Antispam: 1UD129KBjvJXoWxCryrXF4ftryxWF4furW7Arb_yoWrCrWrpF Wrt3WrCw4rGFW7Wrn5Ja17uanaga45WrW7XrWvgw1jyFn7tr17tF13K34UCr13GrW8Wr9F q3ZFvrsxCwn8ZwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUyEb4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_Jr0_JF4l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVW8JVWxJwA2z4x0Y4vEx4A2jsIEc7CjxV AFwI0_Gr0_Gr1UM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40E x7xfMcIj6xIIjxv20xvE14v26r106r15McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x 0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lFIxGxcIEc7CjxVA2Y2ka0xkIwI1l42xK82IYc2Ij 64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67AKxVWUJVWUGwC20s026x 8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r4a6rW5MIIYrxkI7VAKI48JMIIF0xvE 2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E14v26r4j6F4UMIIF0xvE42 xK8VAvwI8IcIk0rVW3JVWrJr1lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY 1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IUbHa0PUUUUU== X-CM-SenderInfo: purev21wro2thvvxqx5xdzvxpfor3voofrz/1tbiAQAMBF1jj5RUFAAAss X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Mon, 2023-09-04 at 15:34 +0200, Roberto Sassu wrote: > From: Roberto Sassu > > In preparation for moving IMA and EVM to the LSM infrastructure, introduce > the inode_post_setattr hook. > > It is useful for EVM to recalculate the HMAC on modified file attributes > and other file metadata, after it verified the HMAC of current file > metadata with the inode_setattr hook. > > LSMs should use the new hook instead of inode_setattr, when they need to > know that the operation was done successfully (not known in inode_setattr). > The new hook cannot return an error and cannot cause the operation to be > reverted. > > Signed-off-by: Roberto Sassu > --- > fs/attr.c | 1 + Hi Christian, Al could you please review and ack patches 12-19, which touch the VFS? Thanks a lot! Roberto > include/linux/lsm_hook_defs.h | 2 ++ > include/linux/security.h | 7 +++++++ > security/security.c | 16 ++++++++++++++++ > 4 files changed, 26 insertions(+) > > diff --git a/fs/attr.c b/fs/attr.c > index 431f667726c7..3c309eb456c6 100644 > --- a/fs/attr.c > +++ b/fs/attr.c > @@ -486,6 +486,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, > > if (!error) { > fsnotify_change(dentry, ia_valid); > + security_inode_post_setattr(idmap, dentry, ia_valid); > ima_inode_post_setattr(idmap, dentry, ia_valid); > evm_inode_post_setattr(idmap, dentry, ia_valid); > } > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h > index fdf075a6b1bb..995d30336cfa 100644 > --- a/include/linux/lsm_hook_defs.h > +++ b/include/linux/lsm_hook_defs.h > @@ -136,6 +136,8 @@ LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode, > LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask) > LSM_HOOK(int, 0, inode_setattr, struct mnt_idmap *idmap, struct dentry *dentry, > struct iattr *attr) > +LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap, > + struct dentry *dentry, int ia_valid) > LSM_HOOK(int, 0, inode_getattr, const struct path *path) > LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap, > struct dentry *dentry, const char *name, const void *value, > diff --git a/include/linux/security.h b/include/linux/security.h > index dcb3604ffab8..820899db5276 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -355,6 +355,8 @@ int security_inode_follow_link(struct dentry *dentry, struct inode *inode, > int security_inode_permission(struct inode *inode, int mask); > int security_inode_setattr(struct mnt_idmap *idmap, > struct dentry *dentry, struct iattr *attr); > +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, > + int ia_valid); > int security_inode_getattr(const struct path *path); > int security_inode_setxattr(struct mnt_idmap *idmap, > struct dentry *dentry, const char *name, > @@ -856,6 +858,11 @@ static inline int security_inode_setattr(struct mnt_idmap *idmap, > return 0; > } > > +static inline void > +security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, > + int ia_valid) > +{ } > + > static inline int security_inode_getattr(const struct path *path) > { > return 0; > diff --git a/security/security.c b/security/security.c > index 2b24d01cf181..764a6f28b3b9 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -2124,6 +2124,22 @@ int security_inode_setattr(struct mnt_idmap *idmap, > } > EXPORT_SYMBOL_GPL(security_inode_setattr); > > +/** > + * security_inode_post_setattr() - Update the inode after a setattr operation > + * @idmap: idmap of the mount > + * @dentry: file > + * @ia_valid: file attributes set > + * > + * Update inode security field after successful setting file attributes. > + */ > +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry, > + int ia_valid) > +{ > + if (unlikely(IS_PRIVATE(d_backing_inode(dentry)))) > + return; > + call_void_hook(inode_post_setattr, idmap, dentry, ia_valid); > +} > + > /** > * security_inode_getattr() - Check if getting file attributes is allowed > * @path: file