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   1 /*
   2  * header.c
   3  *
   4  * Read, write, or print a WIM header.
   5  */
   6
   7 /*
   8  * Copyright 2012-2023 Eric Biggers
   9  *
  10  * This file is free software; you can redistribute it and/or modify it under
  11  * the terms of the GNU Lesser General Public License as published by the Free
  12  * Software Foundation; either version 3 of the License, or (at your option) any
  13  * later version.
  14  *
  15  * This file is distributed in the hope that it will be useful, but WITHOUT
  16  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  17  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  18  * details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this file; if not, see https://www.gnu.org/licenses/.
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #  include "config.h"
  26 #endif
  27
  28 #include <ctype.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32
  33 #include "wimlib.h"
  34 #include "wimlib/alloca.h"
  35 #include "wimlib/assert.h"
  36 #include "wimlib/endianness.h"
  37 #include "wimlib/error.h"
  38 #include "wimlib/file_io.h"
  39 #include "wimlib/header.h"
  40 #include "wimlib/util.h"
  41 #include "wimlib/wim.h"
  42
  43 /*
  44  * Reads the header from a WIM file.
  45  *
  46  * @wim
  47  *      WIM to read the header from.  @wim->in_fd must be positioned at the
  48  *      beginning of the file.
  49  *
  50  * @hdr
  51  *      Structure to read the header into.
  52  *
  53  * Return values:
  54  *      WIMLIB_ERR_SUCCESS (0)
  55  *      WIMLIB_ERR_IMAGE_COUNT
  56  *      WIMLIB_ERR_INVALID_PART_NUMBER
  57  *      WIMLIB_ERR_NOT_A_WIM_FILE
  58  *      WIMLIB_ERR_READ
  59  *      WIMLIB_ERR_UNEXPECTED_END_OF_FILE
  60  *      WIMLIB_ERR_UNKNOWN_VERSION
  61  */
  62 int
  63 read_wim_header(WIMStruct *wim, struct wim_header *hdr)
  64 {
  65         struct wim_header_disk disk_hdr __attribute__((aligned(8)));
  66         struct filedes *in_fd = &wim->in_fd;
  67         const tchar *filename = wim->filename;
  68         int ret;
  69         tchar *pipe_str;
  70
  71         wimlib_assert(in_fd->offset == 0);
  72
  73         if (filename == NULL) {
  74                 pipe_str = alloca(40);
  75                 tsprintf(pipe_str, T("[fd %d]"), in_fd->fd);
  76                 filename = pipe_str;
  77         }
  78
  79         STATIC_ASSERT(sizeof(struct wim_header_disk) == WIM_HEADER_DISK_SIZE);
  80
  81         ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
  82         if (ret)
  83                 goto read_error;
  84
  85         hdr->magic = le64_to_cpu(disk_hdr.magic);
  86
  87         if (hdr->magic != WIM_MAGIC) {
  88                 if (hdr->magic == PWM_MAGIC) {
  89                         /* Pipable WIM:  Use header at end instead, unless
  90                          * actually reading from a pipe.  */
  91                         if (!in_fd->is_pipe) {
  92                                 ret = WIMLIB_ERR_READ;
  93                                 if (-1 == lseek(in_fd->fd, -WIM_HEADER_DISK_SIZE, SEEK_END))
  94                                         goto read_error;
  95                                 ret = full_read(in_fd, &disk_hdr, sizeof(disk_hdr));
  96                                 if (ret)
  97                                         goto read_error;
  98                         }
  99                 } else {
 100                         ERROR("\"%"TS"\": Invalid magic characters in header", filename);
 101                         return WIMLIB_ERR_NOT_A_WIM_FILE;
 102                 }
 103         }
 104
 105         if (le32_to_cpu(disk_hdr.hdr_size) != sizeof(struct wim_header_disk)) {
 106                 ERROR("\"%"TS"\": Header size is invalid (%u bytes)",
 107                       filename, le32_to_cpu(disk_hdr.hdr_size));
 108                 return WIMLIB_ERR_INVALID_HEADER;
 109         }
 110
 111         hdr->wim_version = le32_to_cpu(disk_hdr.wim_version);
 112         if (hdr->wim_version != WIM_VERSION_DEFAULT &&
 113             hdr->wim_version != WIM_VERSION_SOLID)
 114         {
 115                 ERROR("\"%"TS"\": Unknown WIM version: %u",
 116                       filename, hdr->wim_version);
 117                 return WIMLIB_ERR_UNKNOWN_VERSION;
 118         }
 119
 120         hdr->flags = le32_to_cpu(disk_hdr.wim_flags);
 121         hdr->chunk_size = le32_to_cpu(disk_hdr.chunk_size);
 122         copy_guid(hdr->guid, disk_hdr.guid);
 123         hdr->part_number = le16_to_cpu(disk_hdr.part_number);
 124         hdr->total_parts = le16_to_cpu(disk_hdr.total_parts);
 125
 126         if (hdr->total_parts == 0 || hdr->part_number == 0 ||
 127             hdr->part_number > hdr->total_parts)
 128         {
 129                 ERROR("\"%"TS"\": Invalid WIM part number: %hu of %hu",
 130                       filename, hdr->part_number, hdr->total_parts);
 131                 return WIMLIB_ERR_INVALID_PART_NUMBER;
 132         }
 133
 134         hdr->image_count = le32_to_cpu(disk_hdr.image_count);
 135
 136         if (unlikely(hdr->image_count > MAX_IMAGES)) {
 137                 ERROR("\"%"TS"\": Invalid image count (%u)",
 138                       filename, hdr->image_count);
 139                 return WIMLIB_ERR_IMAGE_COUNT;
 140         }
 141
 142         get_wim_reshdr(&disk_hdr.blob_table_reshdr, &hdr->blob_table_reshdr);
 143         get_wim_reshdr(&disk_hdr.xml_data_reshdr, &hdr->xml_data_reshdr);
 144         get_wim_reshdr(&disk_hdr.boot_metadata_reshdr, &hdr->boot_metadata_reshdr);
 145         hdr->boot_idx = le32_to_cpu(disk_hdr.boot_idx);
 146         get_wim_reshdr(&disk_hdr.integrity_table_reshdr, &hdr->integrity_table_reshdr);
 147
 148         /*
 149          * Prevent huge memory allocations when processing fuzzed files.  The
 150          * blob table, XML data, and integrity table are all uncompressed, so
 151          * they should never be larger than the WIM file itself.
 152          */
 153         if (wim->file_size > 0 &&
 154             (hdr->blob_table_reshdr.uncompressed_size > wim->file_size ||
 155              hdr->xml_data_reshdr.uncompressed_size > wim->file_size ||
 156              hdr->integrity_table_reshdr.uncompressed_size > wim->file_size))
 157                 return WIMLIB_ERR_INVALID_HEADER;
 158
 159         return 0;
 160
 161 read_error:
 162         ERROR_WITH_ERRNO("\"%"TS"\": Error reading header", filename);
 163         return ret;
 164 }
 165
 166 /* Writes the header for a WIM file at the specified offset.  If the offset
 167  * specified is the current one, the position is advanced by the size of the
 168  * header.  */
 169 int
 170 write_wim_header(const struct wim_header *hdr, struct filedes *out_fd,
 171                  off_t offset)
 172 {
 173         struct wim_header_disk disk_hdr __attribute__((aligned(8)));
 174         int ret;
 175
 176         disk_hdr.magic = cpu_to_le64(hdr->magic);
 177         disk_hdr.hdr_size = cpu_to_le32(sizeof(struct wim_header_disk));
 178         disk_hdr.wim_version = cpu_to_le32(hdr->wim_version);
 179         disk_hdr.wim_flags = cpu_to_le32(hdr->flags);
 180         disk_hdr.chunk_size = cpu_to_le32(hdr->chunk_size);
 181         copy_guid(disk_hdr.guid, hdr->guid);
 182         disk_hdr.part_number = cpu_to_le16(hdr->part_number);
 183         disk_hdr.total_parts = cpu_to_le16(hdr->total_parts);
 184         disk_hdr.image_count = cpu_to_le32(hdr->image_count);
 185         put_wim_reshdr(&hdr->blob_table_reshdr, &disk_hdr.blob_table_reshdr);
 186         put_wim_reshdr(&hdr->xml_data_reshdr, &disk_hdr.xml_data_reshdr);
 187         put_wim_reshdr(&hdr->boot_metadata_reshdr, &disk_hdr.boot_metadata_reshdr);
 188         disk_hdr.boot_idx = cpu_to_le32(hdr->boot_idx);
 189         put_wim_reshdr(&hdr->integrity_table_reshdr, &disk_hdr.integrity_table_reshdr);
 190         memset(disk_hdr.unused, 0, sizeof(disk_hdr.unused));
 191
 192         if (offset == out_fd->offset)
 193                 ret = full_write(out_fd, &disk_hdr, sizeof(disk_hdr));
 194         else
 195                 ret = full_pwrite(out_fd, &disk_hdr, sizeof(disk_hdr), offset);
 196         if (ret)
 197                 ERROR_WITH_ERRNO("Failed to write WIM header");
 198         return ret;
 199 }
 200
 201 /* Update just the wim_flags field. */
 202 int
 203 write_wim_header_flags(u32 hdr_flags, struct filedes *out_fd)
 204 {
 205         le32 flags = cpu_to_le32(hdr_flags);
 206
 207         return full_pwrite(out_fd, &flags, sizeof(flags),
 208                            offsetof(struct wim_header_disk, wim_flags));
 209 }
 210
 211 static const struct {
 212         u32 flag;
 213         const char *name;
 214 } hdr_flags[] = {
 215         {WIM_HDR_FLAG_RESERVED,         "RESERVED"},
 216         {WIM_HDR_FLAG_COMPRESSION,      "COMPRESSION"},
 217         {WIM_HDR_FLAG_READONLY,         "READONLY"},
 218         {WIM_HDR_FLAG_SPANNED,          "SPANNED"},
 219         {WIM_HDR_FLAG_RESOURCE_ONLY,    "RESOURCE_ONLY"},
 220         {WIM_HDR_FLAG_METADATA_ONLY,    "METADATA_ONLY"},
 221         {WIM_HDR_FLAG_WRITE_IN_PROGRESS,"WRITE_IN_PROGRESS"},
 222         {WIM_HDR_FLAG_RP_FIX,           "RP_FIX"},
 223         {WIM_HDR_FLAG_COMPRESS_RESERVED,"COMPRESS_RESERVED"},
 224         {WIM_HDR_FLAG_COMPRESS_LZX,     "COMPRESS_LZX"},
 225         {WIM_HDR_FLAG_COMPRESS_XPRESS,  "COMPRESS_XPRESS"},
 226         {WIM_HDR_FLAG_COMPRESS_LZMS,    "COMPRESS_LZMS"},
 227         {WIM_HDR_FLAG_COMPRESS_XPRESS_2,"COMPRESS_XPRESS_2"},
 228 };
 229
 230 /* API function documented in wimlib.h  */
 231 WIMLIBAPI void
 232 wimlib_print_header(const WIMStruct *wim)
 233 {
 234         const struct wim_header *hdr = &wim->hdr;
 235
 236         tprintf(T("Magic Characters            = "));
 237         for (int i = 0; i < sizeof(hdr->magic); i++) {
 238                 tchar c = (u8)(hdr->magic >> ((8 * i)));
 239                 if (istalpha(c))
 240                         tputchar(c);
 241                 else
 242                         tprintf(T("\\%o"), c);
 243         }
 244         tputchar(T('\n'));
 245         tprintf(T("Header Size                 = %u\n"), WIM_HEADER_DISK_SIZE);
 246         tprintf(T("Version                     = 0x%x\n"), hdr->wim_version);
 247
 248         tprintf(T("Flags                       = 0x%x\n"), hdr->flags);
 249         for (size_t i = 0; i < ARRAY_LEN(hdr_flags); i++)
 250                 if (hdr_flags[i].flag & hdr->flags)
 251                         tprintf(T("    WIM_HDR_FLAG_%s is set\n"), hdr_flags[i].name);
 252
 253         tprintf(T("Chunk Size                  = %u\n"), hdr->chunk_size);
 254         tfputs (T("GUID                        = "), stdout);
 255         print_byte_field(hdr->guid, GUID_SIZE, stdout);
 256         tputchar(T('\n'));
 257         tprintf(T("Part Number                 = %hu\n"), hdr->part_number);
 258         tprintf(T("Total Parts                 = %hu\n"), hdr->total_parts);
 259         tprintf(T("Image Count                 = %u\n"), hdr->image_count);
 260         tprintf(T("Blob Table Size             = %"PRIu64"\n"),
 261                                 (u64)hdr->blob_table_reshdr.size_in_wim);
 262         tprintf(T("Blob Table Flags            = 0x%hhx\n"),
 263                                 (u8)hdr->blob_table_reshdr.flags);
 264         tprintf(T("Blob Table Offset           = %"PRIu64"\n"),
 265                                 hdr->blob_table_reshdr.offset_in_wim);
 266         tprintf(T("Blob Table Original_size    = %"PRIu64"\n"),
 267                                 hdr->blob_table_reshdr.uncompressed_size);
 268         tprintf(T("XML Data Size               = %"PRIu64"\n"),
 269                                 (u64)hdr->xml_data_reshdr.size_in_wim);
 270         tprintf(T("XML Data Flags              = 0x%hhx\n"),
 271                                 (u8)hdr->xml_data_reshdr.flags);
 272         tprintf(T("XML Data Offset             = %"PRIu64"\n"),
 273                                 hdr->xml_data_reshdr.offset_in_wim);
 274         tprintf(T("XML Data Original Size      = %"PRIu64"\n"),
 275                                 hdr->xml_data_reshdr.uncompressed_size);
 276         tprintf(T("Boot Metadata Size          = %"PRIu64"\n"),
 277                                 (u64)hdr->boot_metadata_reshdr.size_in_wim);
 278         tprintf(T("Boot Metadata Flags         = 0x%hhx\n"),
 279                                 (u8)hdr->boot_metadata_reshdr.flags);
 280         tprintf(T("Boot Metadata Offset        = %"PRIu64"\n"),
 281                                 hdr->boot_metadata_reshdr.offset_in_wim);
 282         tprintf(T("Boot Metadata Original Size = %"PRIu64"\n"),
 283                                 hdr->boot_metadata_reshdr.uncompressed_size);
 284         tprintf(T("Boot Index                  = %u\n"), hdr->boot_idx);
 285         tprintf(T("Integrity Size              = %"PRIu64"\n"),
 286                                 (u64)hdr->integrity_table_reshdr.size_in_wim);
 287         tprintf(T("Integrity Flags             = 0x%hhx\n"),
 288                                 (u8)hdr->integrity_table_reshdr.flags);
 289         tprintf(T("Integrity Offset            = %"PRIu64"\n"),
 290                                 hdr->integrity_table_reshdr.offset_in_wim);
 291         tprintf(T("Integrity Original_size     = %"PRIu64"\n"),
 292                                 hdr->integrity_table_reshdr.uncompressed_size);
 293 }