target/linux/generic/files/drivers/mtd/mtdsplit_uimage.c

   1 /*
   2  *  Copyright (C) 2013 Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  *  This program is free software; you can redistribute it and/or modify it
   5  *  under the terms of the GNU General Public License version 2 as published
   6  *  by the Free Software Foundation.
   7  *
   8  */
   9
  10 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/module.h>
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/mtd/mtd.h>
  18 #include <linux/mtd/partitions.h>
  19 #include <linux/byteorder/generic.h>
  20
  21 #include "mtdsplit.h"
  22
  23 #define IH_MAGIC        0x27051956      /* Image Magic Number           */
  24 #define IH_NMLEN                32      /* Image Name Length            */
  25
  26 #define IH_OS_LINUX             5       /* Linux        */
  27
  28 #define IH_TYPE_KERNEL          2       /* OS Kernel Image              */
  29 #define IH_TYPE_FILESYSTEM      7       /* Filesystem Image             */
  30
  31 /*
  32  * Legacy format image header,
  33  * all data in network byte order (aka natural aka bigendian).
  34  */
  35 struct uimage_header {
  36         uint32_t        ih_magic;       /* Image Header Magic Number    */
  37         uint32_t        ih_hcrc;        /* Image Header CRC Checksum    */
  38         uint32_t        ih_time;        /* Image Creation Timestamp     */
  39         uint32_t        ih_size;        /* Image Data Size              */
  40         uint32_t        ih_load;        /* Data  Load  Address          */
  41         uint32_t        ih_ep;          /* Entry Point Address          */
  42         uint32_t        ih_dcrc;        /* Image Data CRC Checksum      */
  43         uint8_t         ih_os;          /* Operating System             */
  44         uint8_t         ih_arch;        /* CPU architecture             */
  45         uint8_t         ih_type;        /* Image Type                   */
  46         uint8_t         ih_comp;        /* Compression Type             */
  47         uint8_t         ih_name[IH_NMLEN];      /* Image Name           */
  48 };
  49
  50 static int
  51 read_uimage_header(struct mtd_info *mtd, size_t offset,
  52                    struct uimage_header *header)
  53 {
  54         size_t header_len;
  55         size_t retlen;
  56         int ret;
  57
  58         header_len = sizeof(*header);
  59         ret = mtd_read(mtd, offset, header_len, &retlen,
  60                        (unsigned char *) header);
  61         if (ret) {
  62                 pr_debug("read error in \"%s\"\n", mtd->name);
  63                 return ret;
  64         }
  65
  66         if (retlen != header_len) {
  67                 pr_debug("short read in \"%s\"\n", mtd->name);
  68                 return -EIO;
  69         }
  70
  71         return 0;
  72 }
  73
  74 static int __mtdsplit_parse_uimage(struct mtd_info *master,
  75                                    struct mtd_partition **pparts,
  76                                    struct mtd_part_parser_data *data,
  77                                    bool (*verify)(struct uimage_header *hdr))
  78 {
  79         struct mtd_partition *parts;
  80         struct uimage_header *header;
  81         int nr_parts;
  82         size_t offset;
  83         size_t uimage_offset;
  84         size_t uimage_size = 0;
  85         size_t rootfs_offset;
  86         size_t rootfs_size = 0;
  87         int uimage_part, rf_part;
  88         int ret;
  89
  90         nr_parts = 2;
  91         parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
  92         if (!parts)
  93                 return -ENOMEM;
  94
  95         header = vmalloc(sizeof(*header));
  96         if (!header) {
  97                 ret = -ENOMEM;
  98                 goto err_free_parts;
  99         }
 100
 101         /* find uImage on erase block boundaries */
 102         for (offset = 0; offset < master->size; offset += master->erasesize) {
 103                 uimage_size = 0;
 104
 105                 ret = read_uimage_header(master, offset, header);
 106                 if (ret)
 107                         continue;
 108
 109                 if (!verify(header)) {
 110                         pr_debug("no valid uImage found in \"%s\" at offset %llx\n",
 111                                  master->name, (unsigned long long) offset);
 112                         continue;
 113                 }
 114
 115                 uimage_size = sizeof(*header) + be32_to_cpu(header->ih_size);
 116                 if ((offset + uimage_size) > master->size) {
 117                         pr_debug("uImage exceeds MTD device \"%s\"\n",
 118                                  master->name);
 119                         continue;
 120                 }
 121                 break;
 122         }
 123
 124         if (uimage_size == 0) {
 125                 pr_debug("no uImage found in \"%s\"\n", master->name);
 126                 ret = -ENODEV;
 127                 goto err_free_header;
 128         }
 129
 130         uimage_offset = offset;
 131
 132         if (uimage_offset == 0) {
 133                 uimage_part = 0;
 134                 rf_part = 1;
 135
 136                 /* find the roots after the uImage */
 137                 ret = mtd_find_rootfs_from(master,
 138                                            uimage_offset + uimage_size,
 139                                            master->size,
 140                                            &rootfs_offset);
 141                 if (ret) {
 142                         pr_debug("no rootfs after uImage in \"%s\"\n",
 143                                  master->name);
 144                         goto err_free_header;
 145                 }
 146
 147                 rootfs_size = master->size - rootfs_offset;
 148                 uimage_size = rootfs_offset - uimage_offset;
 149         } else {
 150                 rf_part = 0;
 151                 uimage_part = 1;
 152
 153                 /* check rootfs presence at offset 0 */
 154                 ret = mtd_check_rootfs_magic(master, 0);
 155                 if (ret) {
 156                         pr_debug("no rootfs before uImage in \"%s\"\n",
 157                                  master->name);
 158                         goto err_free_header;
 159                 }
 160
 161                 rootfs_offset = 0;
 162                 rootfs_size = uimage_offset;
 163         }
 164
 165         if (rootfs_size == 0) {
 166                 pr_debug("no rootfs found in \"%s\"\n", master->name);
 167                 ret = -ENODEV;
 168                 goto err_free_header;
 169         }
 170
 171         parts[uimage_part].name = KERNEL_PART_NAME;
 172         parts[uimage_part].offset = uimage_offset;
 173         parts[uimage_part].size = uimage_size;
 174
 175         parts[rf_part].name = ROOTFS_PART_NAME;
 176         parts[rf_part].offset = rootfs_offset;
 177         parts[rf_part].size = rootfs_size;
 178
 179         vfree(header);
 180
 181         *pparts = parts;
 182         return nr_parts;
 183
 184 err_free_header:
 185         vfree(header);
 186
 187 err_free_parts:
 188         kfree(parts);
 189         return ret;
 190 }
 191
 192 static bool uimage_verify_default(struct uimage_header *header)
 193 {
 194         /* default sanity checks */
 195         if (be32_to_cpu(header->ih_magic) != IH_MAGIC) {
 196                 pr_debug("invalid uImage magic: %08x\n",
 197                          be32_to_cpu(header->ih_magic));
 198                 return false;
 199         }
 200
 201         if (header->ih_os != IH_OS_LINUX) {
 202                 pr_debug("invalid uImage OS: %08x\n",
 203                          be32_to_cpu(header->ih_os));
 204                 return false;
 205         }
 206
 207         if (header->ih_type != IH_TYPE_KERNEL) {
 208                 pr_debug("invalid uImage type: %08x\n",
 209                          be32_to_cpu(header->ih_type));
 210                 return false;
 211         }
 212
 213         return true;
 214 }
 215
 216 static int
 217 mtdsplit_uimage_parse_generic(struct mtd_info *master,
 218                               struct mtd_partition **pparts,
 219                               struct mtd_part_parser_data *data)
 220 {
 221         return __mtdsplit_parse_uimage(master, pparts, data,
 222                                       uimage_verify_default);
 223 }
 224
 225 static struct mtd_part_parser uimage_generic_parser = {
 226         .owner = THIS_MODULE,
 227         .name = "uimage-fw",
 228         .parse_fn = mtdsplit_uimage_parse_generic,
 229         .type = MTD_PARSER_TYPE_FIRMWARE,
 230 };
 231
 232 #define FW_MAGIC_WNR2000V3      0x32303033
 233 #define FW_MAGIC_WNR2000V4      0x32303034
 234 #define FW_MAGIC_WNR2200        0x32323030
 235 #define FW_MAGIC_WNR612V2       0x32303631
 236 #define FW_MAGIC_WNDR3700       0x33373030
 237 #define FW_MAGIC_WNDR3700V2     0x33373031
 238
 239 static bool uimage_verify_wndr3700(struct uimage_header *header)
 240 {
 241         uint8_t expected_type = IH_TYPE_FILESYSTEM;
 242         switch be32_to_cpu(header->ih_magic) {
 243         case FW_MAGIC_WNR612V2:
 244         case FW_MAGIC_WNR2000V3:
 245         case FW_MAGIC_WNR2200:
 246         case FW_MAGIC_WNDR3700:
 247         case FW_MAGIC_WNDR3700V2:
 248                 break;
 249         case FW_MAGIC_WNR2000V4:
 250                 expected_type = IH_TYPE_KERNEL;
 251                 break;
 252         default:
 253                 return false;
 254         }
 255
 256         if (header->ih_os != IH_OS_LINUX ||
 257             header->ih_type != expected_type)
 258                 return false;
 259
 260         return true;
 261 }
 262
 263 static int
 264 mtdsplit_uimage_parse_netgear(struct mtd_info *master,
 265                               struct mtd_partition **pparts,
 266                               struct mtd_part_parser_data *data)
 267 {
 268         return __mtdsplit_parse_uimage(master, pparts, data,
 269                                       uimage_verify_wndr3700);
 270 }
 271
 272 static struct mtd_part_parser uimage_netgear_parser = {
 273         .owner = THIS_MODULE,
 274         .name = "netgear-fw",
 275         .parse_fn = mtdsplit_uimage_parse_netgear,
 276         .type = MTD_PARSER_TYPE_FIRMWARE,
 277 };
 278
 279 static int __init mtdsplit_uimage_init(void)
 280 {
 281         register_mtd_parser(&uimage_generic_parser);
 282         register_mtd_parser(&uimage_netgear_parser);
 283
 284         return 0;
 285 }
 286
 287 module_init(mtdsplit_uimage_init);