From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965241AbcAULwG (ORCPT ); Thu, 21 Jan 2016 06:52:06 -0500 Received: from mail-pf0-f169.google.com ([209.85.192.169]:33960 "EHLO mail-pf0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759405AbcAULv7 (ORCPT ); Thu, 21 Jan 2016 06:51:59 -0500 Date: Thu, 21 Jan 2016 11:51:51 +0000 From: Matt Fleming To: "Kweh, Hock Leong" Cc: Greg Kroah-Hartman , Ong Boon Leong , LKML , linux-efi@vger.kernel.org, Sam Protsenko , Peter Jones , Andy Lutomirski , Roy Franz , Borislav Petkov , James Bottomley , Linux FS Devel , Anvin H Peter Subject: Re: [PATCH v10 1/1] efi: a misc char interface for user to update efi firmware Message-ID: <20160121115151.GB2510@codeblueprint.co.uk> References: <1450440782-5446-1-git-send-email-hock.leong.kweh@intel.com> <1450440782-5446-2-git-send-email-hock.leong.kweh@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1450440782-5446-2-git-send-email-hock.leong.kweh@intel.com> User-Agent: Mutt/1.5.24+41 (02bc14ed1569) (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 18 Dec, at 08:13:01PM, Kweh Hock Leong wrote: > From: "Kweh, Hock Leong" > > Introducing a kernel module to expose capsule loader interface > (misc char device file note) for user to upload capsule binaries. > > Example method to load the capsule binary: > cat firmware.bin > /dev/efi_capsule_loader > > This patch also export efi_capsule_supported() function symbol for > verifying the submitted capsule header in this kernel module. > > Cc: Matt Fleming > Signed-off-by: Kweh, Hock Leong > --- > drivers/firmware/efi/Kconfig | 10 > drivers/firmware/efi/Makefile | 1 > drivers/firmware/efi/capsule-loader.c | 355 +++++++++++++++++++++++++++++++++ > drivers/firmware/efi/capsule.c | 1 > 4 files changed, 367 insertions(+) > create mode 100644 drivers/firmware/efi/capsule-loader.c [...] > +#define pr_fmt(fmt) "EFI: " fmt > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#define NO_FURTHER_WRITE_ACTION -1 > + > +struct capsule_info { > + bool header_obtained; > + int reset_type; > + long index; > + size_t count; > + size_t total_size; > + struct page **pages; > + size_t page_bytes_remain; > +}; > + > +static DEFINE_MUTEX(capsule_loader_lock); This mutex is not needed. It doesn't protect anything in your code. > +/** > + * efi_free_all_buff_pages - free all previous allocated buffer pages > + * @cap_info: pointer to current instance of capsule_info structure > + * > + * Besides freeing the buffer pages, it also flagged an > + * NO_FURTHER_WRITE_ACTION flag for indicating to the next write entries > + * that there is a flaw happened and any subsequence actions are not > + * valid unless close(2). > + **/ > +static void efi_free_all_buff_pages(struct capsule_info *cap_info) > +{ > + while (cap_info->index > 0) > + __free_page(cap_info->pages[--cap_info->index]); > + > + kfree(cap_info->pages); > + > + cap_info->index = NO_FURTHER_WRITE_ACTION; > +} > + > +/** > + * efi_capsule_setup_info - to obtain the efi capsule header in the binary and > + * setup capsule_info structure > + * @cap_info: pointer to current instance of capsule_info structure > + * @kbuff: a mapped 1st page buffer pointer > + * @hdr_bytes: the total bytes of received efi header > + **/ > +static ssize_t efi_capsule_setup_info(struct capsule_info *cap_info, > + void *kbuff, size_t hdr_bytes) > +{ > + int ret; > + void *temp_page; > + > + /* Handling 1st block is less than header size */ > + if (hdr_bytes < sizeof(efi_capsule_header_t)) { > + if (!cap_info->pages) { > + cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL); > + if (!cap_info->pages) { > + pr_debug("%s: kzalloc() failed\n", __func__); > + return -ENOMEM; > + } > + } This function would be much more simple if you handled the above condition differently. Instead of having code in efi_capsule_setup_info() to allocate the initial ->pages memory, why not just allocate it in efi_capsule_open() at the same time as you allocate the private_data? You can then free it in efi_capsule_release() (you're leaking it at the moment). You are always going to need at least one element in ->pages for successful operation, so you might as well allocate it up front. > + } else { > + /* Reset back to the correct offset of header */ > + efi_capsule_header_t *cap_hdr = kbuff - cap_info->count; > + size_t pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> > + PAGE_SHIFT; > + > + if (pages_needed == 0) { > + pr_err("%s: pages count invalid\n", __func__); > + return -EINVAL; > + } > + > + /* Check if the capsule binary supported */ > + mutex_lock(&capsule_loader_lock); > + ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags, > + cap_hdr->imagesize, > + &cap_info->reset_type); > + mutex_unlock(&capsule_loader_lock); > + if (ret) { > + pr_err("%s: efi_capsule_supported() failed\n", > + __func__); > + return ret; > + } > + > + cap_info->total_size = cap_hdr->imagesize; > + temp_page = krealloc(cap_info->pages, > + pages_needed * sizeof(void *), > + GFP_KERNEL | __GFP_ZERO); > + if (!temp_page) { > + pr_debug("%s: krealloc() failed\n", __func__); > + return -ENOMEM; > + } > + > + cap_info->pages = temp_page; > + cap_info->header_obtained = 1; This should be 'true', not 1. > + } > + > + return 0; > +} > > + > +/** > + * efi_capsule_submit_update - invoke the efi_capsule_update API once binary > + * upload done > + * @cap_info: pointer to current instance of capsule_info structure > + **/ > +static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) > +{ > + int ret; > + void *cap_hdr_temp; > + > + cap_hdr_temp = kmap(cap_info->pages[0]); > + if (!cap_hdr_temp) { > + pr_debug("%s: kmap() failed\n", __func__); > + return -EFAULT; > + } > + > + mutex_lock(&capsule_loader_lock); > + ret = efi_capsule_update(cap_hdr_temp, cap_info->pages); > + mutex_unlock(&capsule_loader_lock); > + kunmap(cap_info->pages[0]); > + if (ret) { > + pr_err("%s: efi_capsule_update() failed\n", __func__); > + return ret; > + } > + > + /* Indicate capsule binary uploading is done */ > + cap_info->index = NO_FURTHER_WRITE_ACTION; > + pr_info("%s: Successfully upload capsule file with reboot type '%s'\n", > + __func__, !cap_info->reset_type ? "RESET_COLD" : > + cap_info->reset_type == 1 ? "RESET_WARM" : > + "RESET_SHUTDOWN"); > + return 0; > +} > + > +/** > + * efi_capsule_write - store the capsule binary and pass it to > + * efi_capsule_update() API > + * @file: file pointer > + * @buff: buffer pointer > + * @count: number of bytes in @buff > + * @offp: not used > + * > + * Expectation: > + * - User space tool should start at the beginning of capsule binary and > + * pass data in sequential. > + * - User should close and re-open this file note in order to upload more > + * capsules. > + * - Any error occurred, user should close the file and restart the > + * operation for the next try otherwise -EIO will be returned until the > + * file is closed. > + * - EFI capsule header must be located at the beginning of capsule binary > + * file and passed in as 1st block write. > + **/ > +static ssize_t efi_capsule_write(struct file *file, const char __user *buff, > + size_t count, loff_t *offp) > +{ > + int ret = 0; > + struct capsule_info *cap_info = file->private_data; > + struct page *kbuff_page = NULL; > + void *kbuff = NULL; > + size_t write_byte; > + > + if (count == 0) > + return 0; > + > + /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ > + if (cap_info->index < 0) > + return -EIO; > + > + /* Only alloc a new page when previous page is full */ > + if (!cap_info->page_bytes_remain) { > + kbuff_page = alloc_page(GFP_KERNEL); > + if (!kbuff_page) { > + pr_debug("%s: alloc_page() failed\n", __func__); > + ret = -ENOMEM; > + goto failed; > + } > + cap_info->page_bytes_remain = PAGE_SIZE; > + } else { > + kbuff_page = cap_info->pages[--cap_info->index]; > + } This shuffling and unshuffling of cap_info->index seems kinda crazy to me because you're treating the current page differently from the rest, which complicates the error paths too (you shouldn't need __free_page() *and* efi_free_all_buff_pages()). Why not make cap_info->index always index the last page? That way you could do, if (!cap_info->page_bytes_remain) { cap_info->pages[++cap_info->index] = alloc_page() cap_info->page_bytes_remain = PAGE_SIZE; } kbuff_page = cap_info->pages[cap_info->index]; ? > + > + kbuff = kmap(kbuff_page); > + if (!kbuff) { > + pr_debug("%s: kmap() failed\n", __func__); > + ret = -EFAULT; > + goto fail_freepage; > + } > + kbuff += PAGE_SIZE - cap_info->page_bytes_remain; > + > + /* Copy capsule binary data from user space to kernel space buffer */ > + write_byte = min_t(size_t, count, cap_info->page_bytes_remain); > + if (copy_from_user(kbuff, buff, write_byte)) { > + pr_debug("%s: copy_from_user() failed\n", __func__); > + ret = -EFAULT; > + goto fail_unmap; > + } > + cap_info->page_bytes_remain -= write_byte; > + > + /* Setup capsule binary info structure */ > + if (!cap_info->header_obtained) { > + ret = efi_capsule_setup_info(cap_info, kbuff, > + cap_info->count + write_byte); > + if (ret) > + goto fail_unmap; > + } > + > + cap_info->pages[cap_info->index++] = kbuff_page; > + cap_info->count += write_byte; > + kunmap(kbuff_page); > + > + /* Submit the full binary to efi_capsule_update() API */ > + if (cap_info->header_obtained && > + cap_info->count >= cap_info->total_size) { > + if (cap_info->count > cap_info->total_size) { > + pr_err("%s: upload size exceeded header defined size\n", > + __func__); > + ret = -EINVAL; > + goto failed; > + } > + > + ret = efi_capsule_submit_update(cap_info); > + if (ret) > + goto failed; > + } > + > + return write_byte; > + > +fail_unmap: > + kunmap(kbuff_page); > +fail_freepage: > + __free_page(kbuff_page); > +failed: > + efi_free_all_buff_pages(cap_info); > + return ret; > +} > + > +/** > + * efi_capsule_flush - called by file close or file flush > + * @file: file pointer > + * @id: not used > + * > + * If capsule being uploaded partially, calling this function will be > + * treated as uploading canceled and will free up those completed buffer > + * pages and then return -ECANCELED. > + **/ > +static int efi_capsule_flush(struct file *file, fl_owner_t id) > +{ > + int ret = 0; > + struct capsule_info *cap_info = file->private_data; > + > + if (cap_info->index > 0) { > + pr_err("%s: capsule upload not complete\n", __func__); > + efi_free_all_buff_pages(cap_info); > + ret = -ECANCELED; > + } > + > + return ret; > +} > + > +/** > + * efi_capsule_release - called by file close > + * @inode: not used > + * @file: file pointer > + * > + * We would not free the successful submitted buffer pages here due to > + * efi update require system reboot with data maintained. > + **/ > +static int efi_capsule_release(struct inode *inode, struct file *file) > +{ > + kfree(file->private_data); > + file->private_data = NULL; > + return 0; > +} > + > +/** > + * efi_capsule_open - called by file open > + * @inode: not used > + * @file: file pointer > + * > + * Will allocate each capsule_info memory for each file open call. > + * This provided the capability to support multiple file open feature > + * where user is not needed to wait for others to finish in order to > + * upload their capsule binary. > + **/ > +static int efi_capsule_open(struct inode *inode, struct file *file) > +{ > + struct capsule_info *cap_info; > + > + cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL); > + if (!cap_info) > + return -ENOMEM; > + > + file->private_data = cap_info; > + Please allocate one ->pages element here (void *). You need at least one for this code to work and you can easily free it in efi_capsule_release() if it still exists. It would also simplfy efi_capsule_setup_info() immensely.