target/linux/generic/files/drivers/mtd/mtdsplit/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 /*
  24  * uimage_header itself is only 64B, but it may be prepended with another data.
  25  * Currently the biggest size is for Edimax devices: 20B + 64B
  26  */
  27 #define MAX_HEADER_LEN          84
  28
  29 #define IH_MAGIC        0x27051956      /* Image Magic Number           */
  30 #define IH_NMLEN                32      /* Image Name Length            */
  31
  32 #define IH_OS_LINUX             5       /* Linux        */
  33
  34 #define IH_TYPE_KERNEL          2       /* OS Kernel Image              */
  35 #define IH_TYPE_FILESYSTEM      7       /* Filesystem Image             */
  36
  37 /*
  38  * Legacy format image header,
  39  * all data in network byte order (aka natural aka bigendian).
  40  */
  41 struct uimage_header {
  42         uint32_t        ih_magic;       /* Image Header Magic Number    */
  43         uint32_t        ih_hcrc;        /* Image Header CRC Checksum    */
  44         uint32_t        ih_time;        /* Image Creation Timestamp     */
  45         uint32_t        ih_size;        /* Image Data Size              */
  46         uint32_t        ih_load;        /* Data  Load  Address          */
  47         uint32_t        ih_ep;          /* Entry Point Address          */
  48         uint32_t        ih_dcrc;        /* Image Data CRC Checksum      */
  49         uint8_t         ih_os;          /* Operating System             */
  50         uint8_t         ih_arch;        /* CPU architecture             */
  51         uint8_t         ih_type;        /* Image Type                   */
  52         uint8_t         ih_comp;        /* Compression Type             */
  53         uint8_t         ih_name[IH_NMLEN];      /* Image Name           */
  54 };
  55
  56 static int
  57 read_uimage_header(struct mtd_info *mtd, size_t offset, u_char *buf,
  58                    size_t header_len)
  59 {
  60         size_t retlen;
  61         int ret;
  62
  63         ret = mtd_read(mtd, offset, header_len, &retlen, buf);
  64         if (ret) {
  65                 pr_debug("read error in \"%s\"\n", mtd->name);
  66                 return ret;
  67         }
  68
  69         if (retlen != header_len) {
  70                 pr_debug("short read in \"%s\"\n", mtd->name);
  71                 return -EIO;
  72         }
  73
  74         return 0;
  75 }
  76
  77 /**
  78  * __mtdsplit_parse_uimage - scan partition and create kernel + rootfs parts
  79  *
  80  * @find_header: function to call for a block of data that will return offset
  81  *      of a valid uImage header if found
  82  */
  83 static int __mtdsplit_parse_uimage(struct mtd_info *master,
  84                                    struct mtd_partition **pparts,
  85                                    struct mtd_part_parser_data *data,
  86                                    ssize_t (*find_header)(u_char *buf, size_t len))
  87 {
  88         struct mtd_partition *parts;
  89         u_char *buf;
  90         int nr_parts;
  91         size_t offset;
  92         size_t uimage_offset;
  93         size_t uimage_size = 0;
  94         size_t rootfs_offset;
  95         size_t rootfs_size = 0;
  96         int uimage_part, rf_part;
  97         int ret;
  98
  99         nr_parts = 2;
 100         parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
 101         if (!parts)
 102                 return -ENOMEM;
 103
 104         buf = vmalloc(MAX_HEADER_LEN);
 105         if (!buf) {
 106                 ret = -ENOMEM;
 107                 goto err_free_parts;
 108         }
 109
 110         /* find uImage on erase block boundaries */
 111         for (offset = 0; offset < master->size; offset += master->erasesize) {
 112                 struct uimage_header *header;
 113
 114                 uimage_size = 0;
 115
 116                 ret = read_uimage_header(master, offset, buf, MAX_HEADER_LEN);
 117                 if (ret)
 118                         continue;
 119
 120                 ret = find_header(buf, MAX_HEADER_LEN);
 121                 if (ret < 0) {
 122                         pr_debug("no valid uImage found in \"%s\" at offset %llx\n",
 123                                  master->name, (unsigned long long) offset);
 124                         continue;
 125                 }
 126                 header = (struct uimage_header *)(buf + ret);
 127
 128                 uimage_size = sizeof(*header) + be32_to_cpu(header->ih_size);
 129                 if ((offset + uimage_size) > master->size) {
 130                         pr_debug("uImage exceeds MTD device \"%s\"\n",
 131                                  master->name);
 132                         continue;
 133                 }
 134                 break;
 135         }
 136
 137         if (uimage_size == 0) {
 138                 pr_debug("no uImage found in \"%s\"\n", master->name);
 139                 ret = -ENODEV;
 140                 goto err_free_buf;
 141         }
 142
 143         uimage_offset = offset;
 144
 145         if (uimage_offset == 0) {
 146                 uimage_part = 0;
 147                 rf_part = 1;
 148
 149                 /* find the roots after the uImage */
 150                 ret = mtd_find_rootfs_from(master, uimage_offset + uimage_size,
 151                                            master->size, &rootfs_offset, NULL);
 152                 if (ret) {
 153                         pr_debug("no rootfs after uImage in \"%s\"\n",
 154                                  master->name);
 155                         goto err_free_buf;
 156                 }
 157
 158                 rootfs_size = master->size - rootfs_offset;
 159                 uimage_size = rootfs_offset - uimage_offset;
 160         } else {
 161                 rf_part = 0;
 162                 uimage_part = 1;
 163
 164                 /* check rootfs presence at offset 0 */
 165                 ret = mtd_check_rootfs_magic(master, 0, NULL);
 166                 if (ret) {
 167                         pr_debug("no rootfs before uImage in \"%s\"\n",
 168                                  master->name);
 169                         goto err_free_buf;
 170                 }
 171
 172                 rootfs_offset = 0;
 173                 rootfs_size = uimage_offset;
 174         }
 175
 176         if (rootfs_size == 0) {
 177                 pr_debug("no rootfs found in \"%s\"\n", master->name);
 178                 ret = -ENODEV;
 179                 goto err_free_buf;
 180         }
 181
 182         parts[uimage_part].name = KERNEL_PART_NAME;
 183         parts[uimage_part].offset = uimage_offset;
 184         parts[uimage_part].size = uimage_size;
 185
 186         parts[rf_part].name = ROOTFS_PART_NAME;
 187         parts[rf_part].offset = rootfs_offset;
 188         parts[rf_part].size = rootfs_size;
 189
 190         vfree(buf);
 191
 192         *pparts = parts;
 193         return nr_parts;
 194
 195 err_free_buf:
 196         vfree(buf);
 197
 198 err_free_parts:
 199         kfree(parts);
 200         return ret;
 201 }
 202
 203 static ssize_t uimage_verify_default(u_char *buf, size_t len)
 204 {
 205         struct uimage_header *header = (struct uimage_header *)buf;
 206
 207         /* default sanity checks */
 208         if (be32_to_cpu(header->ih_magic) != IH_MAGIC) {
 209                 pr_debug("invalid uImage magic: %08x\n",
 210                          be32_to_cpu(header->ih_magic));
 211                 return -EINVAL;
 212         }
 213
 214         if (header->ih_os != IH_OS_LINUX) {
 215                 pr_debug("invalid uImage OS: %08x\n",
 216                          be32_to_cpu(header->ih_os));
 217                 return -EINVAL;
 218         }
 219
 220         if (header->ih_type != IH_TYPE_KERNEL) {
 221                 pr_debug("invalid uImage type: %08x\n",
 222                          be32_to_cpu(header->ih_type));
 223                 return -EINVAL;
 224         }
 225
 226         return 0;
 227 }
 228
 229 static int
 230 mtdsplit_uimage_parse_generic(struct mtd_info *master,
 231                               struct mtd_partition **pparts,
 232                               struct mtd_part_parser_data *data)
 233 {
 234         return __mtdsplit_parse_uimage(master, pparts, data,
 235                                       uimage_verify_default);
 236 }
 237
 238 static struct mtd_part_parser uimage_generic_parser = {
 239         .owner = THIS_MODULE,
 240         .name = "uimage-fw",
 241         .parse_fn = mtdsplit_uimage_parse_generic,
 242         .type = MTD_PARSER_TYPE_FIRMWARE,
 243 };
 244
 245 #define FW_MAGIC_WNR2000V3      0x32303033
 246 #define FW_MAGIC_WNR2000V4      0x32303034
 247 #define FW_MAGIC_WNR2200        0x32323030
 248 #define FW_MAGIC_WNR612V2       0x32303631
 249 #define FW_MAGIC_WNR1000V2      0x31303031
 250 #define FW_MAGIC_WNR1000V2_VC   0x31303030
 251 #define FW_MAGIC_WNDR3700       0x33373030
 252 #define FW_MAGIC_WNDR3700V2     0x33373031
 253 #define FW_MAGIC_WPN824N        0x31313030
 254
 255 static ssize_t uimage_verify_wndr3700(u_char *buf, size_t len)
 256 {
 257         struct uimage_header *header = (struct uimage_header *)buf;
 258         uint8_t expected_type = IH_TYPE_FILESYSTEM;
 259
 260         switch be32_to_cpu(header->ih_magic) {
 261         case FW_MAGIC_WNR612V2:
 262         case FW_MAGIC_WNR1000V2:
 263         case FW_MAGIC_WNR1000V2_VC:
 264         case FW_MAGIC_WNR2000V3:
 265         case FW_MAGIC_WNR2200:
 266         case FW_MAGIC_WNDR3700:
 267         case FW_MAGIC_WNDR3700V2:
 268         case FW_MAGIC_WPN824N:
 269                 break;
 270         case FW_MAGIC_WNR2000V4:
 271                 expected_type = IH_TYPE_KERNEL;
 272                 break;
 273         default:
 274                 return -EINVAL;
 275         }
 276
 277         if (header->ih_os != IH_OS_LINUX ||
 278             header->ih_type != expected_type)
 279                 return -EINVAL;
 280
 281         return 0;
 282 }
 283
 284 static int
 285 mtdsplit_uimage_parse_netgear(struct mtd_info *master,
 286                               struct mtd_partition **pparts,
 287                               struct mtd_part_parser_data *data)
 288 {
 289         return __mtdsplit_parse_uimage(master, pparts, data,
 290                                       uimage_verify_wndr3700);
 291 }
 292
 293 static struct mtd_part_parser uimage_netgear_parser = {
 294         .owner = THIS_MODULE,
 295         .name = "netgear-fw",
 296         .parse_fn = mtdsplit_uimage_parse_netgear,
 297         .type = MTD_PARSER_TYPE_FIRMWARE,
 298 };
 299
 300 /**************************************************
 301  * Edimax
 302  **************************************************/
 303
 304 #define FW_EDIMAX_OFFSET        20
 305 #define FW_MAGIC_EDIMAX         0x43535953
 306
 307 static ssize_t uimage_find_edimax(u_char *buf, size_t len)
 308 {
 309         struct uimage_header *header;
 310
 311         if (len < FW_EDIMAX_OFFSET + sizeof(*header)) {
 312                 pr_err("Buffer too small for checking Edimax header\n");
 313                 return -ENOSPC;
 314         }
 315
 316         header = (struct uimage_header *)(buf + FW_EDIMAX_OFFSET);
 317
 318         switch be32_to_cpu(header->ih_magic) {
 319         case FW_MAGIC_EDIMAX:
 320                 break;
 321         default:
 322                 return -EINVAL;
 323         }
 324
 325         if (header->ih_os != IH_OS_LINUX ||
 326             header->ih_type != IH_TYPE_FILESYSTEM)
 327                 return -EINVAL;
 328
 329         return FW_EDIMAX_OFFSET;
 330 }
 331
 332 static int
 333 mtdsplit_uimage_parse_edimax(struct mtd_info *master,
 334                               struct mtd_partition **pparts,
 335                               struct mtd_part_parser_data *data)
 336 {
 337         return __mtdsplit_parse_uimage(master, pparts, data,
 338                                        uimage_find_edimax);
 339 }
 340
 341 static struct mtd_part_parser uimage_edimax_parser = {
 342         .owner = THIS_MODULE,
 343         .name = "edimax-fw",
 344         .parse_fn = mtdsplit_uimage_parse_edimax,
 345         .type = MTD_PARSER_TYPE_FIRMWARE,
 346 };
 347
 348 /**************************************************
 349  * Init
 350  **************************************************/
 351
 352 static int __init mtdsplit_uimage_init(void)
 353 {
 354         register_mtd_parser(&uimage_generic_parser);
 355         register_mtd_parser(&uimage_netgear_parser);
 356         register_mtd_parser(&uimage_edimax_parser);
 357
 358         return 0;
 359 }
 360
 361 module_init(mtdsplit_uimage_init);