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 782F8C6FA8F for ; Wed, 23 Aug 2023 17:36:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234765AbjHWRgy (ORCPT ); Wed, 23 Aug 2023 13:36:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39374 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236177AbjHWRgy (ORCPT ); Wed, 23 Aug 2023 13:36:54 -0400 Received: from smtp-42af.mail.infomaniak.ch (smtp-42af.mail.infomaniak.ch [84.16.66.175]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E96B5E5A for ; Wed, 23 Aug 2023 10:36:51 -0700 (PDT) Received: from smtp-2-0000.mail.infomaniak.ch (unknown [10.5.36.107]) by smtp-2-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4RWCpT0kvnzMq7yK; Wed, 23 Aug 2023 17:27:45 +0000 (UTC) Received: from unknown by smtp-2-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4RWCpS4XtNzMpnPg; Wed, 23 Aug 2023 19:27:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1692811665; bh=Af92qxekJvnIMxE2huAbL4crBOgqYOL6Fa4l2jIwrRg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cnQhU/5MAOPdwJJ4S0jVmYsdf4yX45TNkxLPr3Qpuyqe9QY6R2kocp1kmKnWyrsTT 7NKdedEyl6WzmmgXXdfxAhopYJjhcwLB05bFRwXUIiwjvEmWbOhE+h+I3pYHLg3HG1 Jx58yJItV9lxAGo/GQzapLvv7ZTsqf8U4KVWhyis= Date: Wed, 23 Aug 2023 19:27:43 +0200 From: =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= To: Casey Schaufler Cc: paul@paul-moore.com, linux-security-module@vger.kernel.org, jmorris@namei.org, serge@hallyn.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, stephen.smalley.work@gmail.com, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH v13 04/11] LSM: syscalls for current process attributes Message-ID: <20230823.dohCegee9die@digikod.net> References: <20230802174435.11928-1-casey@schaufler-ca.com> <20230802174435.11928-5-casey@schaufler-ca.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230802174435.11928-5-casey@schaufler-ca.com> X-Infomaniak-Routing: alpha Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Aug 02, 2023 at 10:44:27AM -0700, Casey Schaufler wrote: > Create a system call lsm_get_self_attr() to provide the security > module maintained attributes of the current process. > Create a system call lsm_set_self_attr() to set a security > module maintained attribute of the current process. > Historically these attributes have been exposed to user space via > entries in procfs under /proc/self/attr. > > The attribute value is provided in a lsm_ctx structure. The structure > identifies the size of the attribute, and the attribute value. The format > of the attribute value is defined by the security module. A flags field > is included for LSM specific information. It is currently unused and must > be 0. The total size of the data, including the lsm_ctx structure and any > padding, is maintained as well. > > struct lsm_ctx { > __u64 id; > __u64 flags; > __u64 len; > __u64 ctx_len; > __u8 ctx[]; > }; > > Two new LSM hooks are used to interface with the LSMs. > security_getselfattr() collects the lsm_ctx values from the > LSMs that support the hook, accounting for space requirements. > security_setselfattr() identifies which LSM the attribute is > intended for and passes it along. > > Signed-off-by: Casey Schaufler > Reviewed-by: Kees Cook > Reviewed-by: Serge Hallyn > --- > Documentation/userspace-api/lsm.rst | 70 ++++++++++++++++ > include/linux/lsm_hook_defs.h | 4 + > include/linux/lsm_hooks.h | 1 + > include/linux/security.h | 19 +++++ > include/linux/syscalls.h | 5 ++ > include/uapi/linux/lsm.h | 90 ++++++++++++++++++++ > kernel/sys_ni.c | 2 + > security/Makefile | 1 + > security/lsm_syscalls.c | 55 ++++++++++++ > security/security.c | 125 ++++++++++++++++++++++++++++ > 10 files changed, 372 insertions(+) > create mode 100644 Documentation/userspace-api/lsm.rst > create mode 100644 include/uapi/linux/lsm.h > create mode 100644 security/lsm_syscalls.c > +/** > + * security_setselfattr - Set an LSM attribute on the current process. > + * @attr: which attribute to set > + * @ctx: the user-space source for the information > + * @size: the size of the data > + * @flags: reserved for future use, must be 0 > + * > + * Set an LSM attribute for the current process. The LSM, attribute > + * and new value are included in @ctx. > + * > + * Returns 0 on success, -EINVAL if the input is inconsistent, -EFAULT > + * if the user buffer is inaccessible or an LSM specific failure. > + */ > +int security_setselfattr(unsigned int attr, struct lsm_ctx __user *ctx, > + size_t size, u32 flags) > +{ > + struct security_hook_list *hp; > + struct lsm_ctx *lctx; > + int rc = LSM_RET_DEFAULT(setselfattr); > + > + if (flags) > + return -EINVAL; > + if (size < sizeof(*ctx)) > + return -EINVAL; > + > + lctx = kmalloc(size, GFP_KERNEL); > + if (lctx == NULL) > + return -ENOMEM; > + > + if (copy_from_user(&lctx, ctx, size)) This should be copy_from_user(lctx, ctx, size) > + return -EFAULT; > + > + if (size < lctx->len || size < lctx->ctx_len + sizeof(ctx) || > + lctx->len < lctx->ctx_len + sizeof(ctx)) > + return -EINVAL; > + > + hlist_for_each_entry(hp, &security_hook_heads.setselfattr, list) > + if ((hp->lsmid->id) == lctx->id) { > + rc = hp->hook.setselfattr(attr, lctx, size, flags); > + break; > + } > + > + kfree(lctx); > + return rc; > +} > + > /** > * security_getprocattr() - Read an attribute for a task > * @p: the task > -- > 2.41.0 >