From patchwork Wed Feb 8 21:58:28 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Scott Bauer X-Patchwork-Id: 725843 X-Patchwork-Delegate: scottwood@freescale.com Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [103.22.144.68]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3vJbDP0jT6z9s7D for ; Thu, 9 Feb 2017 09:17:25 +1100 (AEDT) Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 3vJbDN74MrzDqDR for ; Thu, 9 Feb 2017 09:17:24 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3vJb1P4nK6zDq8X for ; Thu, 9 Feb 2017 09:07:52 +1100 (AEDT) Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP; 08 Feb 2017 14:07:50 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,348,1484035200"; d="scan'208";a="56705214" Received: from sbauer-z170x-ud5.lm.intel.com (HELO sbauer-Z170X-UD5) ([10.232.112.157]) by orsmga004.jf.intel.com with ESMTP; 08 Feb 2017 14:07:49 -0800 Date: Wed, 8 Feb 2017 14:58:28 -0700 From: Scott Bauer To: Arnd Bergmann Subject: Re: [PATCH] block: sed-opal: reduce stack size of ioctl handler Message-ID: <20170208215827.GA9733@sbauer-Z170X-UD5> References: <20170208211546.2789607-1-arnd@arndb.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20170208211546.2789607-1-arnd@arndb.de> User-Agent: Mutt/1.5.24 (2015-08-30) X-Mailman-Approved-At: Thu, 09 Feb 2017 09:16:29 +1100 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , Rafael Antognolli , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org, hch@lst.de, Jonathan Derrick Errors-To: linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, Feb 08, 2017 at 10:15:28PM +0100, Arnd Bergmann wrote: > When CONFIG_KASAN is in use, the sed_ioctl function uses unusually large stack, > as each possible ioctl argument gets its own stack area plus redzone: > > block/sed-opal.c: In function 'sed_ioctl': > block/sed-opal.c:2447:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] > > Moving the copy_from_user() calls into the individual functions has little > effect on readablility, but significantly reduces the stack size, with the > largest individual function (opal_enable_disable_shadow_mbr) now at > reasonable 456 bytes. > > Fixes: 455a7b238cd6 ("block: Add Sed-opal library") > Signed-off-by: Arnd Bergmann Hi Arnd, Thank you for the report. We want to keep the function calls agnostic to userland. In the future we will have in-kernel callers and I don't want to have to do any get_fs(KERNEL_DS) wizardry. Instead I think we can use a union to lessen the stack burden. I tested this patch just now with config_ksasan and was able to build. From dfa6a2c842a6e45cab198c9058e753835a81521e Mon Sep 17 00:00:00 2001 From: Scott Bauer Date: Wed, 8 Feb 2017 14:49:32 -0700 Subject: [PATCH] Unionize stack parameters for sed_ioctl to prevent oversized stack block/sed-opal.c: In function 'sed_ioctl': block/sed-opal.c:2447:1: error: the frame size of 2256 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] Moved all the ioctl structures into a union to prevent oversized stack frame size. Fixes: 455a7b238cd6 ("block: Add Sed-opal library") Reported-by: Arnd Bergmann Signed-off-by: Scott Bauer --- block/sed-opal.c | 118 ++++++++++++++++++++++--------------------------------- 1 file changed, 46 insertions(+), 72 deletions(-) diff --git a/block/sed-opal.c b/block/sed-opal.c index bf1406e..f509168 100644 --- a/block/sed-opal.c +++ b/block/sed-opal.c @@ -2347,6 +2347,15 @@ EXPORT_SYMBOL(opal_unlock_from_suspend); int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr) { void __user *arg = (void __user *)ptr; + union { + struct opal_lock_unlock lk_unlk; + struct opal_key opal_key; + struct opal_lr_act opal_lr_act; + struct opal_new_pw opal_pw; + struct opal_session_info session; + struct opal_user_lr_setup lrs; + struct opal_mbr_data mbr; + }u; if (!capable(CAP_SYS_ADMIN)) return -EACCES; @@ -2355,91 +2364,56 @@ int sed_ioctl(struct opal_dev *dev, unsigned int cmd, unsigned long ptr) return -ENOTSUPP; } + memset(&u, 0, sizeof(u)); switch (cmd) { - case IOC_OPAL_SAVE: { - struct opal_lock_unlock lk_unlk; - - if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk))) + case IOC_OPAL_SAVE: + if (copy_from_user(&u.lk_unlk, arg, sizeof(u.lk_unlk))) return -EFAULT; - return opal_save(dev, &lk_unlk); - } - case IOC_OPAL_LOCK_UNLOCK: { - struct opal_lock_unlock lk_unlk; - - if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk))) + return opal_save(dev, &u.lk_unlk); + case IOC_OPAL_LOCK_UNLOCK: + if (copy_from_user(&u.lk_unlk, arg, sizeof(u.lk_unlk))) return -EFAULT; - return opal_lock_unlock(dev, &lk_unlk); - } - case IOC_OPAL_TAKE_OWNERSHIP: { - struct opal_key opal_key; - - if (copy_from_user(&opal_key, arg, sizeof(opal_key))) + return opal_lock_unlock(dev, &u.lk_unlk); + case IOC_OPAL_TAKE_OWNERSHIP: + if (copy_from_user(&u.opal_key, arg, sizeof(u.opal_key))) return -EFAULT; - return opal_take_ownership(dev, &opal_key); - } - case IOC_OPAL_ACTIVATE_LSP: { - struct opal_lr_act opal_lr_act; - - if (copy_from_user(&opal_lr_act, arg, sizeof(opal_lr_act))) + return opal_take_ownership(dev, &u.opal_key); + case IOC_OPAL_ACTIVATE_LSP: + if (copy_from_user(&u.opal_lr_act, arg, sizeof(u.opal_lr_act))) return -EFAULT; - return opal_activate_lsp(dev, &opal_lr_act); - } - case IOC_OPAL_SET_PW: { - struct opal_new_pw opal_pw; - - if (copy_from_user(&opal_pw, arg, sizeof(opal_pw))) + return opal_activate_lsp(dev, &u.opal_lr_act); + case IOC_OPAL_SET_PW: + if (copy_from_user(&u.opal_pw, arg, sizeof(u.opal_pw))) return -EFAULT; - return opal_set_new_pw(dev, &opal_pw); - } - case IOC_OPAL_ACTIVATE_USR: { - struct opal_session_info session; - - if (copy_from_user(&session, arg, sizeof(session))) + return opal_set_new_pw(dev, &u.opal_pw); + case IOC_OPAL_ACTIVATE_USR: + if (copy_from_user(&u.session, arg, sizeof(u.session))) return -EFAULT; - return opal_activate_user(dev, &session); - } - case IOC_OPAL_REVERT_TPR: { - struct opal_key opal_key; - - if (copy_from_user(&opal_key, arg, sizeof(opal_key))) + return opal_activate_user(dev, &u.session); + case IOC_OPAL_REVERT_TPR: + if (copy_from_user(&u.opal_key, arg, sizeof(u.opal_key))) return -EFAULT; - return opal_reverttper(dev, &opal_key); - } - case IOC_OPAL_LR_SETUP: { - struct opal_user_lr_setup lrs; - - if (copy_from_user(&lrs, arg, sizeof(lrs))) + return opal_reverttper(dev, &u.opal_key); + case IOC_OPAL_LR_SETUP: + if (copy_from_user(&u.lrs, arg, sizeof(u.lrs))) return -EFAULT; - return opal_setup_locking_range(dev, &lrs); - } - case IOC_OPAL_ADD_USR_TO_LR: { - struct opal_lock_unlock lk_unlk; - - if (copy_from_user(&lk_unlk, arg, sizeof(lk_unlk))) + return opal_setup_locking_range(dev, &u.lrs); + case IOC_OPAL_ADD_USR_TO_LR: + if (copy_from_user(&u.lk_unlk, arg, sizeof(u.lk_unlk))) return -EFAULT; - return opal_add_user_to_lr(dev, &lk_unlk); - } - case IOC_OPAL_ENABLE_DISABLE_MBR: { - struct opal_mbr_data mbr; - - if (copy_from_user(&mbr, arg, sizeof(mbr))) + return opal_add_user_to_lr(dev, &u.lk_unlk); + case IOC_OPAL_ENABLE_DISABLE_MBR: + if (copy_from_user(&u.mbr, arg, sizeof(u.mbr))) return -EFAULT; - return opal_enable_disable_shadow_mbr(dev, &mbr); - } - case IOC_OPAL_ERASE_LR: { - struct opal_session_info session; - - if (copy_from_user(&session, arg, sizeof(session))) + return opal_enable_disable_shadow_mbr(dev, &u.mbr); + case IOC_OPAL_ERASE_LR: + if (copy_from_user(&u.session, arg, sizeof(u.session))) return -EFAULT; - return opal_erase_locking_range(dev, &session); - } - case IOC_OPAL_SECURE_ERASE_LR: { - struct opal_session_info session; - - if (copy_from_user(&session, arg, sizeof(session))) + return opal_erase_locking_range(dev, &u.session); + case IOC_OPAL_SECURE_ERASE_LR: + if (copy_from_user(&u.session, arg, sizeof(u.session))) return -EFAULT; - return opal_secure_erase_locking_range(dev, &session); - } + return opal_secure_erase_locking_range(dev, &u.session); default: pr_warn("No such Opal Ioctl %u\n", cmd); }