From patchwork Tue Oct 12 13:23:07 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 12552583 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB460C433FE for ; Tue, 12 Oct 2021 13:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C67F661040 for ; Tue, 12 Oct 2021 13:23:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236677AbhJLNZ2 (ORCPT ); Tue, 12 Oct 2021 09:25:28 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:59116 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236890AbhJLNZT (ORCPT ); Tue, 12 Oct 2021 09:25:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634044995; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type; bh=16Pi/Vl3z4Y6fWeRQLWZMbFJzaAfXOnksHfTN4qiRaM=; b=T464ilO0MzkK7hRRpBtP41rxFU1nItnGbJh/H1mEzWULLsjdDayWq+mPii2CVswppJOrBm ahZWWnIr8dINJW87eocsDa0P9AmCs7hD1E4GQasdApmCMOIki0uz4Ta78uIpCUNZR/EypS eg9jDJpbpYvWBxUhCR8cx1irK5d3xRs= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-516-N96qR4scM5GRFblvNBpOUQ-1; Tue, 12 Oct 2021 09:23:12 -0400 X-MC-Unique: N96qR4scM5GRFblvNBpOUQ-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7615A801AA7; Tue, 12 Oct 2021 13:23:09 +0000 (UTC) Received: from horse.redhat.com (unknown [10.22.9.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id DFA845D9C6; Tue, 12 Oct 2021 13:23:07 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 1DA0822023A; Tue, 12 Oct 2021 09:23:07 -0400 (EDT) Date: Tue, 12 Oct 2021 09:23:07 -0400 From: Vivek Goyal To: jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, serge@hallyn.com Cc: linux-fsdevel@vger.kernel.org, virtio-fs@redhat.com, Miklos Szeredi , dwalsh@redhat.com, jlayton@kernel.org, idryomov@gmail.com, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, bfields@fieldses.org, chuck.lever@oracle.com, anna.schumaker@netapp.com, trond.myklebust@hammerspace.com, stephen.smalley.work@gmail.com, casey@schaufler-ca.com, Ondrej Mosnacek Subject: [PATCH v2] security: Return xattr name from security_dentry_init_security() Message-ID: MIME-Version: 1.0 Content-Disposition: inline X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Precedence: bulk List-ID: Right now security_dentry_init_security() only supports single security label and is used by SELinux only. There are two users of of this hook, namely ceph and nfs. NFS does not care about xattr name. Ceph hardcodes the xattr name to security.selinux (XATTR_NAME_SELINUX). I am making changes to fuse/virtiofs to send security label to virtiofsd and I need to send xattr name as well. I also hardcoded the name of xattr to security.selinux. Stephen Smalley suggested that it probably is a good idea to modify security_dentry_init_security() to also return name of xattr so that we can avoid this hardcoding in the callers. This patch adds a new parameter "const char **xattr_name" to security_dentry_init_security() and LSM puts the name of xattr too if caller asked for it (xattr_name != NULL). Signed-off-by: Vivek Goyal Reviewed-by: Jeff Layton Reviewed-by: Christian Brauner Acked-by: James Morris --- Changes since v1: - Updated comment to make it clear caller does not have to free the xattr_name. (Jeff Layton). - Captured Jeff's Reviewed-by ack. I have tested this patch with virtiofs and compile tested for ceph and nfs. NFS changes are trivial. Looking for an ack from NFS maintainers. --- fs/ceph/xattr.c | 3 +-- fs/nfs/nfs4proc.c | 3 ++- include/linux/lsm_hook_defs.h | 3 ++- include/linux/lsm_hooks.h | 3 +++ include/linux/security.h | 6 ++++-- security/security.c | 7 ++++--- security/selinux/hooks.c | 6 +++++- 7 files changed, 21 insertions(+), 10 deletions(-) Index: redhat-linux/security/selinux/hooks.c =================================================================== --- redhat-linux.orig/security/selinux/hooks.c 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/security/selinux/hooks.c 2021-10-06 15:20:57.745247170 -0400 @@ -2948,7 +2948,8 @@ static void selinux_inode_free_security( } static int selinux_dentry_init_security(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, + const struct qstr *name, + const char **xattr_name, void **ctx, u32 *ctxlen) { u32 newsid; @@ -2961,6 +2962,9 @@ static int selinux_dentry_init_security( if (rc) return rc; + if (xattr_name) + *xattr_name = XATTR_NAME_SELINUX; + return security_sid_to_context(&selinux_state, newsid, (char **)ctx, ctxlen); } Index: redhat-linux/security/security.c =================================================================== --- redhat-linux.orig/security/security.c 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/security/security.c 2021-10-06 15:20:57.749247170 -0400 @@ -1052,11 +1052,12 @@ void security_inode_free(struct inode *i } int security_dentry_init_security(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, - u32 *ctxlen) + const struct qstr *name, + const char **xattr_name, void **ctx, + u32 *ctxlen) { return call_int_hook(dentry_init_security, -EOPNOTSUPP, dentry, mode, - name, ctx, ctxlen); + name, xattr_name, ctx, ctxlen); } EXPORT_SYMBOL(security_dentry_init_security); Index: redhat-linux/include/linux/lsm_hooks.h =================================================================== --- redhat-linux.orig/include/linux/lsm_hooks.h 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/include/linux/lsm_hooks.h 2021-10-12 09:05:00.830399245 -0400 @@ -196,6 +196,9 @@ * @dentry dentry to use in calculating the context. * @mode mode used to determine resource type. * @name name of the last path component used to create file + * @xattr_name pointer to place the pointer to security xattr name. + * Caller does not have to free the resulting pointer. Its + * a pointer to static string. * @ctx pointer to place the pointer to the resulting context in. * @ctxlen point to place the length of the resulting context. * @dentry_create_files_as: Index: redhat-linux/include/linux/security.h =================================================================== --- redhat-linux.orig/include/linux/security.h 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/include/linux/security.h 2021-10-06 15:20:57.751247170 -0400 @@ -317,8 +317,9 @@ int security_add_mnt_opt(const char *opt int len, void **mnt_opts); int security_move_mount(const struct path *from_path, const struct path *to_path); int security_dentry_init_security(struct dentry *dentry, int mode, - const struct qstr *name, void **ctx, - u32 *ctxlen); + const struct qstr *name, + const char **xattr_name, void **ctx, + u32 *ctxlen); int security_dentry_create_files_as(struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, @@ -739,6 +740,7 @@ static inline void security_inode_free(s static inline int security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, + const char **xattr_name, void **ctx, u32 *ctxlen) { Index: redhat-linux/include/linux/lsm_hook_defs.h =================================================================== --- redhat-linux.orig/include/linux/lsm_hook_defs.h 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/include/linux/lsm_hook_defs.h 2021-10-06 15:20:57.752247170 -0400 @@ -83,7 +83,8 @@ LSM_HOOK(int, 0, sb_add_mnt_opt, const c LSM_HOOK(int, 0, move_mount, const struct path *from_path, const struct path *to_path) LSM_HOOK(int, 0, dentry_init_security, struct dentry *dentry, - int mode, const struct qstr *name, void **ctx, u32 *ctxlen) + int mode, const struct qstr *name, const char **xattr_name, + void **ctx, u32 *ctxlen) LSM_HOOK(int, 0, dentry_create_files_as, struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, struct cred *new) Index: redhat-linux/fs/nfs/nfs4proc.c =================================================================== --- redhat-linux.orig/fs/nfs/nfs4proc.c 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/fs/nfs/nfs4proc.c 2021-10-06 15:20:57.754247170 -0400 @@ -127,7 +127,8 @@ nfs4_label_init_security(struct inode *d return NULL; err = security_dentry_init_security(dentry, sattr->ia_mode, - &dentry->d_name, (void **)&label->label, &label->len); + &dentry->d_name, NULL, + (void **)&label->label, &label->len); if (err == 0) return label; Index: redhat-linux/fs/ceph/xattr.c =================================================================== --- redhat-linux.orig/fs/ceph/xattr.c 2021-10-04 15:40:28.978453324 -0400 +++ redhat-linux/fs/ceph/xattr.c 2021-10-06 15:20:57.756247170 -0400 @@ -1311,7 +1311,7 @@ int ceph_security_init_secctx(struct den int err; err = security_dentry_init_security(dentry, mode, &dentry->d_name, - &as_ctx->sec_ctx, + &name, &as_ctx->sec_ctx, &as_ctx->sec_ctxlen); if (err < 0) { WARN_ON_ONCE(err != -EOPNOTSUPP); @@ -1335,7 +1335,6 @@ int ceph_security_init_secctx(struct den * It only supports single security module and only selinux has * dentry_init_security hook. */ - name = XATTR_NAME_SELINUX; name_len = strlen(name); err = ceph_pagelist_reserve(pagelist, 4 * 2 + name_len + as_ctx->sec_ctxlen);