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 #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 /**
  75  * __mtdsplit_parse_uimage - scan partition and create kernel + rootfs parts
  76  *
  77  * @find_header: function to call for a block of data that will return offset
  78  *      of a valid uImage header if found
  79  */
  80 static int __mtdsplit_parse_uimage(struct mtd_info *master,
  81                                    struct mtd_partition **pparts,
  82                                    struct mtd_part_parser_data *data,
  83                                    ssize_t (*find_header)(u_char *buf, size_t len))
  84 {
  85         struct mtd_partition *parts;
  86         struct uimage_header *header;
  87         int nr_parts;
  88         size_t offset;
  89         size_t uimage_offset;
  90         size_t uimage_size = 0;
  91         size_t rootfs_offset;
  92         size_t rootfs_size = 0;
  93         int uimage_part, rf_part;
  94         int ret;
  95
  96         nr_parts = 2;
  97         parts = kzalloc(nr_parts * sizeof(*parts), GFP_KERNEL);
  98         if (!parts)
  99                 return -ENOMEM;
 100
 101         header = vmalloc(sizeof(*header));
 102         if (!header) {
 103                 ret = -ENOMEM;
 104                 goto err_free_parts;
 105         }
 106
 107         /* find uImage on erase block boundaries */
 108         for (offset = 0; offset < master->size; offset += master->erasesize) {
 109                 uimage_size = 0;
 110
 111                 ret = read_uimage_header(master, offset, header);
 112                 if (ret)
 113                         continue;
 114
 115                 ret = find_header((u_char *)header, sizeof(*header));
 116                 if (ret < 0) {
 117                         pr_debug("no valid uImage found in \"%s\" at offset %llx\n",
 118                                  master->name, (unsigned long long) offset);
 119                         continue;
 120                 }
 121                 if (ret > 0) {
 122                         pr_warn("extra header offsets are not supported yet\n");
 123                         continue;
 124                 }
 125
 126                 uimage_size = sizeof(*header) + be32_to_cpu(header->ih_size);
 127                 if ((offset + uimage_size) > master->size) {
 128                         pr_debug("uImage exceeds MTD device \"%s\"\n",
 129                                  master->name);
 130                         continue;
 131                 }
 132                 break;
 133         }
 134
 135         if (uimage_size == 0) {
 136                 pr_debug("no uImage found in \"%s\"\n", master->name);
 137                 ret = -ENODEV;
 138                 goto err_free_header;
 139         }
 140
 141         uimage_offset = offset;
 142
 143         if (uimage_offset == 0) {
 144                 uimage_part = 0;
 145                 rf_part = 1;
 146
 147                 /* find the roots after the uImage */
 148                 ret = mtd_find_rootfs_from(master,
 149                                            uimage_offset + uimage_size,
 150                                            master->size,
 151                                            &rootfs_offset);
 152                 if (ret) {
 153                         pr_debug("no rootfs after uImage in \"%s\"\n",
 154                                  master->name);
 155                         goto err_free_header;
 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);
 166                 if (ret) {
 167                         pr_debug("no rootfs before uImage in \"%s\"\n",
 168                                  master->name);
 169                         goto err_free_header;
 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_header;
 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(header);
 191
 192         *pparts = parts;
 193         return nr_parts;
 194
 195 err_free_header:
 196         vfree(header);
 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
 254 static ssize_t uimage_verify_wndr3700(u_char *buf, size_t len)
 255 {
 256         struct uimage_header *header = (struct uimage_header *)buf;
 257         uint8_t expected_type = IH_TYPE_FILESYSTEM;
 258
 259         switch be32_to_cpu(header->ih_magic) {
 260         case FW_MAGIC_WNR612V2:
 261         case FW_MAGIC_WNR1000V2:
 262         case FW_MAGIC_WNR1000V2_VC:
 263         case FW_MAGIC_WNR2000V3:
 264         case FW_MAGIC_WNR2200:
 265         case FW_MAGIC_WNDR3700:
 266         case FW_MAGIC_WNDR3700V2:
 267                 break;
 268         case FW_MAGIC_WNR2000V4:
 269                 expected_type = IH_TYPE_KERNEL;
 270                 break;
 271         default:
 272                 return -EINVAL;
 273         }
 274
 275         if (header->ih_os != IH_OS_LINUX ||
 276             header->ih_type != expected_type)
 277                 return -EINVAL;
 278
 279         return 0;
 280 }
 281
 282 static int
 283 mtdsplit_uimage_parse_netgear(struct mtd_info *master,
 284                               struct mtd_partition **pparts,
 285                               struct mtd_part_parser_data *data)
 286 {
 287         return __mtdsplit_parse_uimage(master, pparts, data,
 288                                       uimage_verify_wndr3700);
 289 }
 290
 291 static struct mtd_part_parser uimage_netgear_parser = {
 292         .owner = THIS_MODULE,
 293         .name = "netgear-fw",
 294         .parse_fn = mtdsplit_uimage_parse_netgear,
 295         .type = MTD_PARSER_TYPE_FIRMWARE,
 296 };
 297
 298 static int __init mtdsplit_uimage_init(void)
 299 {
 300         register_mtd_parser(&uimage_generic_parser);
 301         register_mtd_parser(&uimage_netgear_parser);
 302
 303         return 0;
 304 }
 305
 306 module_init(mtdsplit_uimage_init);