+/*
+ * Copyright (C) 2018 Paweł Dembicki <paweldembicki@gmail.com>
+ *
+ * Based on: mtdsplit_uimage.c
+ * Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/byteorder/generic.h>
+
+#include "mtdsplit.h"
+
+#define MAX_HEADER_LEN ( STAG_SIZE + SCH2_SIZE )
+
+#define STAG_SIZE 16
+#define STAG_ID 0x04
+#define STAG_MAGIC 0x2B24
+
+#define SCH2_SIZE 40
+#define SCH2_MAGIC 0x2124
+#define SCH2_VER 0x02
+
+/*
+ * Jboot image header,
+ * all data in little endian.
+ */
+
+struct jimage_header //stag + sch2 jboot joined headers
+{
+ uint8_t stag_cmark; // in factory 0xFF , in sysupgrade must be the same as stag_id
+ uint8_t stag_id; // 0x04
+ uint16_t stag_magic; //magic 0x2B24
+ uint32_t stag_time_stamp; // timestamp calculated in jboot way
+ uint32_t stag_image_length; // lentgh of kernel + sch2 header
+ uint16_t stag_image_checksum; // negated jboot_checksum of sch2 + kernel
+ uint16_t stag_tag_checksum; // negated jboot_checksum of stag header data
+ uint16_t sch2_magic; // magic 0x2124
+ uint8_t sch2_cp_type; // 0x00 for flat, 0x01 for jz, 0x02 for gzip, 0x03 for lzma
+ uint8_t sch2_version; // 0x02 for sch2
+ uint32_t sch2_ram_addr; // ram entry address
+ uint32_t sch2_image_len; // kernel image length
+ uint32_t sch2_image_crc32; // kernel image crc
+ uint32_t sch2_start_addr; // ram start address
+ uint32_t sch2_rootfs_addr; // rootfs flash address
+ uint32_t sch2_rootfs_len; // rootfls length
+ uint32_t sch2_rootfs_crc32; // rootfs crc32
+ uint32_t sch2_header_crc32; // sch2 header crc32, durring calculation this area is replaced by zero
+ uint16_t sch2_header_length; // sch2 header length: 0x28
+ uint16_t sch2_cmd_line_length; // cmd line length, known zeros
+};
+
+static int
+read_jimage_header(struct mtd_info *mtd, size_t offset, u_char *buf,
+ size_t header_len)
+{
+ size_t retlen;
+ int ret;
+
+ ret = mtd_read(mtd, offset, header_len, &retlen, buf);
+ if (ret) {
+ pr_debug("read error in \"%s\"\n", mtd->name);
+ return ret;
+ }
+
+ if (retlen != header_len) {
+ pr_debug("short read in \"%s\"\n", mtd->name);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+/**
+ * __mtdsplit_parse_jimage - scan partition and create kernel + rootfs parts
+ *
+ * @find_header: function to call for a block of data that will return offset
+ * of a valid jImage header if found
+ */
+static int __mtdsplit_parse_jimage(struct mtd_info *master,
+ const struct mtd_partition **pparts,
+ struct mtd_part_parser_data *data,
+ ssize_t (*find_header)(u_char *buf, size_t len))
+{
+ struct mtd_partition *parts;
+ u_char *buf;
+ int nr_parts;
+ size_t offset;
+ size_t jimage_offset;
+ size_t jimage_size = 0;
+ size_t rootfs_offset;
+ size_t rootfs_size = 0;
+ int jimage_part, rf_part;
+ int ret;
+ enum mtdsplit_part_type type;
+
+ nr_parts = 2;
+ parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
+ if (!parts)
+ return -ENOMEM;
+
+ buf = vmalloc(MAX_HEADER_LEN);
+ if (!buf) {
+ ret = -ENOMEM;
+ goto err_free_parts;
+ }
+
+ /* find jImage on erase block boundaries */
+ for (offset = 0; offset < master->size; offset += master->erasesize) {
+ struct jimage_header *header;
+
+ jimage_size = 0;
+
+ ret = read_jimage_header(master, offset, buf, MAX_HEADER_LEN);
+ if (ret)
+ continue;
+
+ ret = find_header(buf, MAX_HEADER_LEN);
+ if (ret < 0) {
+ pr_debug("no valid jImage found in \"%s\" at offset %llx\n",
+ master->name, (unsigned long long) offset);
+ continue;
+ }
+ header = (struct jimage_header *)(buf + ret);
+
+ jimage_size = sizeof(*header) + header->sch2_image_len + ret;
+ if ((offset + jimage_size) > master->size) {
+ pr_debug("jImage exceeds MTD device \"%s\"\n",
+ master->name);
+ continue;
+ }
+ break;
+ }
+
+ if (jimage_size == 0) {
+ pr_debug("no jImage found in \"%s\"\n", master->name);
+ ret = -ENODEV;
+ goto err_free_buf;
+ }
+
+ jimage_offset = offset;
+
+ if (jimage_offset == 0) {
+ jimage_part = 0;
+ rf_part = 1;
+
+ /* find the roots after the jImage */
+ ret = mtd_find_rootfs_from(master, jimage_offset + jimage_size,
+ master->size, &rootfs_offset, &type);
+ if (ret) {
+ pr_debug("no rootfs after jImage in \"%s\"\n",
+ master->name);
+ goto err_free_buf;
+ }
+
+ rootfs_size = master->size - rootfs_offset;
+ jimage_size = rootfs_offset - jimage_offset;
+ } else {
+ rf_part = 0;
+ jimage_part = 1;
+
+ /* check rootfs presence at offset 0 */
+ ret = mtd_check_rootfs_magic(master, 0, &type);
+ if (ret) {
+ pr_debug("no rootfs before jImage in \"%s\"\n",
+ master->name);
+ goto err_free_buf;
+ }
+
+ rootfs_offset = 0;
+ rootfs_size = jimage_offset;
+ }
+
+ if (rootfs_size == 0) {
+ pr_debug("no rootfs found in \"%s\"\n", master->name);
+ ret = -ENODEV;
+ goto err_free_buf;
+ }
+
+ parts[jimage_part].name = KERNEL_PART_NAME;
+ parts[jimage_part].offset = jimage_offset;
+ parts[jimage_part].size = jimage_size;
+
+ if (type == MTDSPLIT_PART_TYPE_UBI)
+ parts[rf_part].name = UBI_PART_NAME;
+ else
+ parts[rf_part].name = ROOTFS_PART_NAME;
+ parts[rf_part].offset = rootfs_offset;
+ parts[rf_part].size = rootfs_size;
+
+ vfree(buf);
+
+ *pparts = parts;
+ return nr_parts;
+
+err_free_buf:
+ vfree(buf);
+
+err_free_parts:
+ kfree(parts);
+ return ret;
+}
+
+static ssize_t jimage_verify_default(u_char *buf, size_t len)
+{
+ struct jimage_header *header = (struct jimage_header *)buf;
+
+ /* default sanity checks */
+ if (header->stag_magic != STAG_MAGIC) {
+ pr_debug("invalid jImage stag header magic: %04x\n",
+ header->stag_magic);
+ return -EINVAL;
+ }
+ if (header->sch2_magic != SCH2_MAGIC) {
+ pr_debug("invalid jImage sch2 header magic: %04x\n",
+ header->stag_magic);
+ return -EINVAL;
+ }
+ if (header->stag_cmark != header->stag_id) {
+ pr_debug("invalid jImage stag header cmark: %02x\n",
+ header->stag_magic);
+ return -EINVAL;
+ }
+ if (header->stag_id != STAG_ID) {
+ pr_debug("invalid jImage stag header id: %02x\n",
+ header->stag_magic);
+ return -EINVAL;
+ }
+ if (header->sch2_version != SCH2_VER) {
+ pr_debug("invalid jImage sch2 header version: %02x\n",
+ header->stag_magic);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int
+mtdsplit_jimage_parse_generic(struct mtd_info *master,
+ const struct mtd_partition **pparts,
+ struct mtd_part_parser_data *data)
+{
+ return __mtdsplit_parse_jimage(master, pparts, data,
+ jimage_verify_default);
+}
+
+static struct mtd_part_parser jimage_generic_parser = {
+ .owner = THIS_MODULE,
+ .name = "jimage-fw",
+ .parse_fn = mtdsplit_jimage_parse_generic,
+ .type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
+/**************************************************
+ * Init
+ **************************************************/
+
+static int __init mtdsplit_jimage_init(void)
+{
+ register_mtd_parser(&jimage_generic_parser);
+
+ return 0;
+}
+
+module_init(mtdsplit_jimage_init);
projects / openwrt / openwrt.git / commitdiff