// SPDX-License-Identifier: GPL-2.0-or-later/* * Copyright 2021 Google LLC. */ #include <linux/init.h>#include <linux/highmem.h>#include <linux/kobject.h>#include <linux/mm.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/sysfs.h>#include <linux/vmalloc.h> #include "internal.h" static int module_extend_max_pages(struct load_info *info, unsigned int extent){	struct page **new_pages; 	new_pages = kvmalloc_array(info->max_pages + extent,				   sizeof(info->pages), GFP_KERNEL);	if (!new_pages)		return -ENOMEM; 	memcpy(new_pages, info->pages, info->max_pages * sizeof(info->pages));	kvfree(info->pages);	info->pages = new_pages;	info->max_pages += extent; 	return 0;} static struct page *module_get_next_page(struct load_info *info){	struct page *page;	int error; 	if (info->max_pages == info->used_pages) {		error = module_extend_max_pages(info, info->used_pages);		if (error)			return ERR_PTR(error);	} 	page = alloc_page(GFP_KERNEL | __GFP_HIGHMEM);	if (!page)		return ERR_PTR(-ENOMEM); 	info->pages[info->used_pages++] = page;	return page;} #ifdef CONFIG_MODULE_COMPRESS_GZIP#include <linux/zlib.h>#define MODULE_COMPRESSION	gzip#define MODULE_DECOMPRESS_FN	module_gzip_decompress /* * Calculate length of the header which consists of signature, header * flags, time stamp and operating system ID (10 bytes total), plus * an optional filename. */static size_t module_gzip_header_len(const u8 *buf, size_t size){	const u8 signature[] = { 0x1f, 0x8b, 0x08 };	size_t len = 10; 	if (size < len || memcmp(buf, signature, sizeof(signature)))		return 0; 	if (buf[3] & 0x08) {		do {			/*			 * If we can't find the end of the file name we must			 * be dealing with a corrupted file.			 */			if (len == size)				return 0;		} while (buf[len++] != '\0');	} 	return len;} static ssize_t module_gzip_decompress(struct load_info *info,				      const void *buf, size_t size){	struct z_stream_s s = { 0 };	size_t new_size = 0;	size_t gzip_hdr_len;	ssize_t retval;	int rc; 	gzip_hdr_len = module_gzip_header_len(buf, size);	if (!gzip_hdr_len) {		pr_err("not a gzip compressed module\n");		return -EINVAL;	} 	s.next_in = buf + gzip_hdr_len;	s.avail_in = size - gzip_hdr_len; 	s.workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);	if (!s.workspace)		return -ENOMEM; 	rc = zlib_inflateInit2(&s, -MAX_WBITS);	if (rc != Z_OK) {		pr_err("failed to initialize decompressor: %d\n", rc);		retval = -EINVAL;		goto out;	} 	do {		struct page *page = module_get_next_page(info); 		if (!page) {			retval = -ENOMEM;			goto out_inflate_end;		} 		s.next_out = kmap_local_page(page);		s.avail_out = PAGE_SIZE;		rc = zlib_inflate(&s, 0);		kunmap_local(s.next_out); 		new_size += PAGE_SIZE - s.avail_out;	} while (rc == Z_OK); 	if (rc != Z_STREAM_END) {		pr_err("decompression failed with status %d\n", rc);		retval = -EINVAL;		goto out_inflate_end;	} 	retval = new_size; out_inflate_end:	zlib_inflateEnd(&s);out:	kfree(s.workspace);	return retval;}#elif CONFIG_MODULE_COMPRESS_XZ#include <linux/xz.h>#define MODULE_COMPRESSION	xz#define MODULE_DECOMPRESS_FN	module_xz_decompress static ssize_t module_xz_decompress(struct load_info *info,				    const void *buf, size_t size){	static const u8 signature[] = { 0xfd, '7', 'z', 'X', 'Z', 0 };	struct xz_dec *xz_dec;	struct xz_buf xz_buf;	enum xz_ret xz_ret;	size_t new_size = 0;	ssize_t retval; 	if (size < sizeof(signature) ||	    memcmp(buf, signature, sizeof(signature))) {		pr_err("not an xz compressed module\n");		return -EINVAL;	} 	xz_dec = xz_dec_init(XZ_DYNALLOC, (u32)-1);	if (!xz_dec)		return -ENOMEM; 	xz_buf.in_size = size;	xz_buf.in = buf;	xz_buf.in_pos = 0; 	do {		struct page *page = module_get_next_page(info); 		if (!page) {			retval = -ENOMEM;			goto out;		} 		xz_buf.out = kmap_local_page(page);		xz_buf.out_pos = 0;		xz_buf.out_size = PAGE_SIZE;		xz_ret = xz_dec_run(xz_dec, &xz_buf);		kunmap_local(xz_buf.out); 		new_size += xz_buf.out_pos;	} while (xz_buf.out_pos == PAGE_SIZE && xz_ret == XZ_OK); 	if (xz_ret != XZ_STREAM_END) {		pr_err("decompression failed with status %d\n", xz_ret);		retval = -EINVAL;		goto out;	} 	retval = new_size;  out:	xz_dec_end(xz_dec);	return retval;}#else#error "Unexpected configuration for CONFIG_MODULE_DECOMPRESS"#endif int module_decompress(struct load_info *info, const void *buf, size_t size){	unsigned int n_pages;	ssize_t data_size;	int error; 	/*	 * Start with number of pages twice as big as needed for	 * compressed data.	 */	n_pages = DIV_ROUND_UP(size, PAGE_SIZE) * 2;	error = module_extend_max_pages(info, n_pages); 	data_size = MODULE_DECOMPRESS_FN(info, buf, size);	if (data_size < 0) {		error = data_size;		goto err;	} 	info->hdr = vmap(info->pages, info->used_pages, VM_MAP, PAGE_KERNEL);	if (!info->hdr) {		error = -ENOMEM;		goto err;	} 	info->len = data_size;	return 0; err:	module_decompress_cleanup(info);	return error;} void module_decompress_cleanup(struct load_info *info){	int i; 	if (info->hdr)		vunmap(info->hdr); 	for (i = 0; i < info->used_pages; i++)		__free_page(info->pages[i]); 	kvfree(info->pages); 	info->pages = NULL;	info->max_pages = info->used_pages = 0;} #ifdef CONFIG_SYSFSstatic ssize_t compression_show(struct kobject *kobj,				struct kobj_attribute *attr, char *buf){	return sysfs_emit(buf, __stringify(MODULE_COMPRESSION) "\n");} static struct kobj_attribute module_compression_attr = __ATTR_RO(compression); static int __init module_decompress_sysfs_init(void){	int error; 	error = sysfs_create_file(&module_kset->kobj,				  &module_compression_attr.attr);	if (error)		pr_warn("Failed to create 'compression' attribute"); 	return 0;}late_initcall(module_decompress_sysfs_init);#endif