cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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capsule-loader.c (9267B)


      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * EFI capsule loader driver.
      4 *
      5 * Copyright 2015 Intel Corporation
      6 */
      7
      8#define pr_fmt(fmt) "efi: " fmt
      9
     10#include <linux/kernel.h>
     11#include <linux/module.h>
     12#include <linux/miscdevice.h>
     13#include <linux/highmem.h>
     14#include <linux/io.h>
     15#include <linux/slab.h>
     16#include <linux/mutex.h>
     17#include <linux/efi.h>
     18#include <linux/vmalloc.h>
     19
     20#define NO_FURTHER_WRITE_ACTION -1
     21
     22/**
     23 * efi_free_all_buff_pages - free all previous allocated buffer pages
     24 * @cap_info: pointer to current instance of capsule_info structure
     25 *
     26 *	In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
     27 *	to cease processing data in subsequent write(2) calls until close(2)
     28 *	is called.
     29 **/
     30static void efi_free_all_buff_pages(struct capsule_info *cap_info)
     31{
     32	while (cap_info->index > 0)
     33		__free_page(cap_info->pages[--cap_info->index]);
     34
     35	cap_info->index = NO_FURTHER_WRITE_ACTION;
     36}
     37
     38int __efi_capsule_setup_info(struct capsule_info *cap_info)
     39{
     40	size_t pages_needed;
     41	int ret;
     42	void *temp_page;
     43
     44	pages_needed = ALIGN(cap_info->total_size, PAGE_SIZE) / PAGE_SIZE;
     45
     46	if (pages_needed == 0) {
     47		pr_err("invalid capsule size\n");
     48		return -EINVAL;
     49	}
     50
     51	/* Check if the capsule binary supported */
     52	ret = efi_capsule_supported(cap_info->header.guid,
     53				    cap_info->header.flags,
     54				    cap_info->header.imagesize,
     55				    &cap_info->reset_type);
     56	if (ret) {
     57		pr_err("capsule not supported\n");
     58		return ret;
     59	}
     60
     61	temp_page = krealloc(cap_info->pages,
     62			     pages_needed * sizeof(void *),
     63			     GFP_KERNEL | __GFP_ZERO);
     64	if (!temp_page)
     65		return -ENOMEM;
     66
     67	cap_info->pages = temp_page;
     68
     69	temp_page = krealloc(cap_info->phys,
     70			     pages_needed * sizeof(phys_addr_t *),
     71			     GFP_KERNEL | __GFP_ZERO);
     72	if (!temp_page)
     73		return -ENOMEM;
     74
     75	cap_info->phys = temp_page;
     76
     77	return 0;
     78}
     79
     80/**
     81 * efi_capsule_setup_info - obtain the efi capsule header in the binary and
     82 *			    setup capsule_info structure
     83 * @cap_info: pointer to current instance of capsule_info structure
     84 * @kbuff: a mapped first page buffer pointer
     85 * @hdr_bytes: the total received number of bytes for efi header
     86 *
     87 * Platforms with non-standard capsule update mechanisms can override
     88 * this __weak function so they can perform any required capsule
     89 * image munging. See quark_quirk_function() for an example.
     90 **/
     91int __weak efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
     92				  size_t hdr_bytes)
     93{
     94	/* Only process data block that is larger than efi header size */
     95	if (hdr_bytes < sizeof(efi_capsule_header_t))
     96		return 0;
     97
     98	memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
     99	cap_info->total_size = cap_info->header.imagesize;
    100
    101	return __efi_capsule_setup_info(cap_info);
    102}
    103
    104/**
    105 * efi_capsule_submit_update - invoke the efi_capsule_update API once binary
    106 *			       upload done
    107 * @cap_info: pointer to current instance of capsule_info structure
    108 **/
    109static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
    110{
    111	bool do_vunmap = false;
    112	int ret;
    113
    114	/*
    115	 * cap_info->capsule may have been assigned already by a quirk
    116	 * handler, so only overwrite it if it is NULL
    117	 */
    118	if (!cap_info->capsule) {
    119		cap_info->capsule = vmap(cap_info->pages, cap_info->index,
    120					 VM_MAP, PAGE_KERNEL);
    121		if (!cap_info->capsule)
    122			return -ENOMEM;
    123		do_vunmap = true;
    124	}
    125
    126	ret = efi_capsule_update(cap_info->capsule, cap_info->phys);
    127	if (do_vunmap)
    128		vunmap(cap_info->capsule);
    129	if (ret) {
    130		pr_err("capsule update failed\n");
    131		return ret;
    132	}
    133
    134	/* Indicate capsule binary uploading is done */
    135	cap_info->index = NO_FURTHER_WRITE_ACTION;
    136
    137	if (cap_info->header.flags & EFI_CAPSULE_PERSIST_ACROSS_RESET) {
    138		pr_info("Successfully uploaded capsule file with reboot type '%s'\n",
    139			!cap_info->reset_type ? "RESET_COLD" :
    140			cap_info->reset_type == 1 ? "RESET_WARM" :
    141			"RESET_SHUTDOWN");
    142	} else {
    143		pr_info("Successfully processed capsule file\n");
    144	}
    145
    146	return 0;
    147}
    148
    149/**
    150 * efi_capsule_write - store the capsule binary and pass it to
    151 *		       efi_capsule_update() API
    152 * @file: file pointer
    153 * @buff: buffer pointer
    154 * @count: number of bytes in @buff
    155 * @offp: not used
    156 *
    157 *	Expectation:
    158 *	- A user space tool should start at the beginning of capsule binary and
    159 *	  pass data in sequentially.
    160 *	- Users should close and re-open this file note in order to upload more
    161 *	  capsules.
    162 *	- After an error returned, user should close the file and restart the
    163 *	  operation for the next try otherwise -EIO will be returned until the
    164 *	  file is closed.
    165 *	- An EFI capsule header must be located at the beginning of capsule
    166 *	  binary file and passed in as first block data of write operation.
    167 **/
    168static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
    169				 size_t count, loff_t *offp)
    170{
    171	int ret;
    172	struct capsule_info *cap_info = file->private_data;
    173	struct page *page;
    174	void *kbuff = NULL;
    175	size_t write_byte;
    176
    177	if (count == 0)
    178		return 0;
    179
    180	/* Return error while NO_FURTHER_WRITE_ACTION is flagged */
    181	if (cap_info->index < 0)
    182		return -EIO;
    183
    184	/* Only alloc a new page when previous page is full */
    185	if (!cap_info->page_bytes_remain) {
    186		page = alloc_page(GFP_KERNEL);
    187		if (!page) {
    188			ret = -ENOMEM;
    189			goto failed;
    190		}
    191
    192		cap_info->pages[cap_info->index] = page;
    193		cap_info->phys[cap_info->index] = page_to_phys(page);
    194		cap_info->page_bytes_remain = PAGE_SIZE;
    195		cap_info->index++;
    196	} else {
    197		page = cap_info->pages[cap_info->index - 1];
    198	}
    199
    200	kbuff = kmap(page);
    201	kbuff += PAGE_SIZE - cap_info->page_bytes_remain;
    202
    203	/* Copy capsule binary data from user space to kernel space buffer */
    204	write_byte = min_t(size_t, count, cap_info->page_bytes_remain);
    205	if (copy_from_user(kbuff, buff, write_byte)) {
    206		ret = -EFAULT;
    207		goto fail_unmap;
    208	}
    209	cap_info->page_bytes_remain -= write_byte;
    210
    211	/* Setup capsule binary info structure */
    212	if (cap_info->header.headersize == 0) {
    213		ret = efi_capsule_setup_info(cap_info, kbuff - cap_info->count,
    214					     cap_info->count + write_byte);
    215		if (ret)
    216			goto fail_unmap;
    217	}
    218
    219	cap_info->count += write_byte;
    220	kunmap(page);
    221
    222	/* Submit the full binary to efi_capsule_update() API */
    223	if (cap_info->header.headersize > 0 &&
    224	    cap_info->count >= cap_info->total_size) {
    225		if (cap_info->count > cap_info->total_size) {
    226			pr_err("capsule upload size exceeded header defined size\n");
    227			ret = -EINVAL;
    228			goto failed;
    229		}
    230
    231		ret = efi_capsule_submit_update(cap_info);
    232		if (ret)
    233			goto failed;
    234	}
    235
    236	return write_byte;
    237
    238fail_unmap:
    239	kunmap(page);
    240failed:
    241	efi_free_all_buff_pages(cap_info);
    242	return ret;
    243}
    244
    245/**
    246 * efi_capsule_flush - called by file close or file flush
    247 * @file: file pointer
    248 * @id: not used
    249 *
    250 *	If a capsule is being partially uploaded then calling this function
    251 *	will be treated as upload termination and will free those completed
    252 *	buffer pages and -ECANCELED will be returned.
    253 **/
    254static int efi_capsule_flush(struct file *file, fl_owner_t id)
    255{
    256	int ret = 0;
    257	struct capsule_info *cap_info = file->private_data;
    258
    259	if (cap_info->index > 0) {
    260		pr_err("capsule upload not complete\n");
    261		efi_free_all_buff_pages(cap_info);
    262		ret = -ECANCELED;
    263	}
    264
    265	return ret;
    266}
    267
    268/**
    269 * efi_capsule_release - called by file close
    270 * @inode: not used
    271 * @file: file pointer
    272 *
    273 *	We will not free successfully submitted pages since efi update
    274 *	requires data to be maintained across system reboot.
    275 **/
    276static int efi_capsule_release(struct inode *inode, struct file *file)
    277{
    278	struct capsule_info *cap_info = file->private_data;
    279
    280	kfree(cap_info->pages);
    281	kfree(cap_info->phys);
    282	kfree(file->private_data);
    283	file->private_data = NULL;
    284	return 0;
    285}
    286
    287/**
    288 * efi_capsule_open - called by file open
    289 * @inode: not used
    290 * @file: file pointer
    291 *
    292 *	Will allocate each capsule_info memory for each file open call.
    293 *	This provided the capability to support multiple file open feature
    294 *	where user is not needed to wait for others to finish in order to
    295 *	upload their capsule binary.
    296 **/
    297static int efi_capsule_open(struct inode *inode, struct file *file)
    298{
    299	struct capsule_info *cap_info;
    300
    301	cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
    302	if (!cap_info)
    303		return -ENOMEM;
    304
    305	cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
    306	if (!cap_info->pages) {
    307		kfree(cap_info);
    308		return -ENOMEM;
    309	}
    310
    311	cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL);
    312	if (!cap_info->phys) {
    313		kfree(cap_info->pages);
    314		kfree(cap_info);
    315		return -ENOMEM;
    316	}
    317
    318	file->private_data = cap_info;
    319
    320	return 0;
    321}
    322
    323static const struct file_operations efi_capsule_fops = {
    324	.owner = THIS_MODULE,
    325	.open = efi_capsule_open,
    326	.write = efi_capsule_write,
    327	.flush = efi_capsule_flush,
    328	.release = efi_capsule_release,
    329	.llseek = no_llseek,
    330};
    331
    332static struct miscdevice efi_capsule_misc = {
    333	.minor = MISC_DYNAMIC_MINOR,
    334	.name = "efi_capsule_loader",
    335	.fops = &efi_capsule_fops,
    336};
    337
    338static int __init efi_capsule_loader_init(void)
    339{
    340	int ret;
    341
    342	if (!efi_enabled(EFI_RUNTIME_SERVICES))
    343		return -ENODEV;
    344
    345	ret = misc_register(&efi_capsule_misc);
    346	if (ret)
    347		pr_err("Unable to register capsule loader device\n");
    348
    349	return ret;
    350}
    351module_init(efi_capsule_loader_init);
    352
    353static void __exit efi_capsule_loader_exit(void)
    354{
    355	misc_deregister(&efi_capsule_misc);
    356}
    357module_exit(efi_capsule_loader_exit);
    358
    359MODULE_DESCRIPTION("EFI capsule firmware binary loader");
    360MODULE_LICENSE("GPL v2");