grub/grub-core/io/lzopio.c

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/* lzopio.c - decompression support for lzop */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2011 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/err.h>
#include <grub/mm.h>
#include <grub/file.h>
#include <grub/fs.h>
#include <grub/dl.h>
#include <grub/crypto.h>
#include <minilzo.h>
GRUB_MOD_LICENSE ("GPLv3+");
#define LZOP_MAGIC "\x89\x4c\x5a\x4f\x00\x0d\x0a\x1a\x0a"
#define LZOP_MAGIC_SIZE 9
#define LZOP_CHECK_SIZE 4
#define LZOP_NEW_LIB 0x0940
/* Header flags - copied from conf.h of LZOP source code. */
#define F_ADLER32_D 0x00000001L
#define F_ADLER32_C 0x00000002L
#define F_STDIN 0x00000004L
#define F_STDOUT 0x00000008L
#define F_NAME_DEFAULT 0x00000010L
#define F_DOSISH 0x00000020L
#define F_H_EXTRA_FIELD 0x00000040L
#define F_H_GMTDIFF 0x00000080L
#define F_CRC32_D 0x00000100L
#define F_CRC32_C 0x00000200L
#define F_MULTIPART 0x00000400L
#define F_H_FILTER 0x00000800L
#define F_H_CRC32 0x00001000L
#define F_H_PATH 0x00002000L
#define F_MASK 0x00003FFFL
struct block_header
{
grub_uint32_t usize;
grub_uint32_t csize;
grub_uint32_t ucheck;
grub_uint32_t ccheck;
unsigned char *cdata;
unsigned char *udata;
};
struct grub_lzopio
{
grub_file_t file;
int has_ccheck;
int has_ucheck;
const gcry_md_spec_t *ucheck_fun;
const gcry_md_spec_t *ccheck_fun;
grub_off_t saved_off; /* Rounded down to block boundary. */
grub_off_t start_block_off;
struct block_header block;
};
typedef struct grub_lzopio *grub_lzopio_t;
static struct grub_fs grub_lzopio_fs;
/* Some helper functions. On errors memory allocated by those function is free
* either on close() so no risk of leaks. This makes functions simpler. */
/* Read block header from file, after successful exit file points to
* beginning of block data. */
static int
read_block_header (struct grub_lzopio *lzopio)
{
lzopio->saved_off += lzopio->block.usize;
/* Free cached block data if any. */
grub_free (lzopio->block.udata);
grub_free (lzopio->block.cdata);
lzopio->block.udata = NULL;
lzopio->block.cdata = NULL;
if (grub_file_read (lzopio->file, &lzopio->block.usize,
sizeof (lzopio->block.usize)) !=
sizeof (lzopio->block.usize))
return -1;
lzopio->block.usize = grub_be_to_cpu32 (lzopio->block.usize);
/* Last block has uncompressed data size == 0 and no other fields. */
if (lzopio->block.usize == 0)
{
if (grub_file_tell (lzopio->file) == grub_file_size (lzopio->file))
return 0;
else
return -1;
}
/* Read compressed data block size. */
if (grub_file_read (lzopio->file, &lzopio->block.csize,
sizeof (lzopio->block.csize)) !=
sizeof (lzopio->block.csize))
return -1;
lzopio->block.csize = grub_be_to_cpu32 (lzopio->block.csize);
/* Corrupted. */
if (lzopio->block.csize > lzopio->block.usize)
return -1;
/* Read checksum of uncompressed data. */
if (lzopio->has_ucheck)
{
if (grub_file_read (lzopio->file, &lzopio->block.ucheck,
sizeof (lzopio->block.ucheck)) !=
sizeof (lzopio->block.ucheck))
return -1;
lzopio->block.ucheck = lzopio->block.ucheck;
}
/* Read checksum of compressed data. */
if (lzopio->has_ccheck)
{
/* Incompressible data block. */
if (lzopio->block.csize == lzopio->block.usize)
{
lzopio->block.ccheck = lzopio->block.ucheck;
}
else
{
if (grub_file_read (lzopio->file, &lzopio->block.ccheck,
sizeof (lzopio->block.ccheck)) !=
sizeof (lzopio->block.ccheck))
return -1;
lzopio->block.ccheck = lzopio->block.ccheck;
}
}
return 0;
}
/* Read block data into memory. File must be set to beginning of block data.
* Can't be called on last block. */
static int
read_block_data (struct grub_lzopio *lzopio)
{
lzopio->block.cdata = grub_malloc (lzopio->block.csize);
if (!lzopio->block.cdata)
return -1;
if (grub_file_read (lzopio->file, lzopio->block.cdata, lzopio->block.csize)
!= (grub_ssize_t) lzopio->block.csize)
return -1;
if (lzopio->ccheck_fun)
{
GRUB_PROPERLY_ALIGNED_ARRAY (context, lzopio->ccheck_fun->contextsize);
lzopio->ccheck_fun->init (context);
lzopio->ccheck_fun->write (context, lzopio->block.cdata,
lzopio->block.csize);
lzopio->ccheck_fun->final (context);
if (grub_memcmp
(lzopio->ccheck_fun->read (context), &lzopio->block.ccheck,
sizeof (lzopio->block.ccheck)) != 0)
return -1;
}
return 0;
}
/* Read block data, uncompressed and also store it in memory. */
/* XXX Investigate possibility of in-place decompression to reduce memory
* footprint. Or try to uncompress directly to buf if possible. */
static int
uncompress_block (struct grub_lzopio *lzopio)
{
lzo_uint usize = lzopio->block.usize;
if (read_block_data (lzopio) < 0)
return -1;
/* Incompressible data. */
if (lzopio->block.csize == lzopio->block.usize)
{
lzopio->block.udata = lzopio->block.cdata;
lzopio->block.cdata = NULL;
}
else
{
lzopio->block.udata = grub_malloc (lzopio->block.usize);
if (!lzopio->block.udata)
return -1;
if (lzo1x_decompress_safe (lzopio->block.cdata, lzopio->block.csize,
lzopio->block.udata, &usize, NULL)
!= LZO_E_OK)
return -1;
if (lzopio->ucheck_fun)
{
GRUB_PROPERLY_ALIGNED_ARRAY (context, lzopio->ucheck_fun->contextsize);
lzopio->ucheck_fun->init (context);
lzopio->ucheck_fun->write (context, lzopio->block.udata,
lzopio->block.usize);
lzopio->ucheck_fun->final (context);
if (grub_memcmp
(lzopio->ucheck_fun->read (context), &lzopio->block.ucheck,
sizeof (lzopio->block.ucheck)) != 0)
return -1;
}
/* Compressed data can be free now. */
grub_free (lzopio->block.cdata);
lzopio->block.cdata = NULL;
}
return 0;
}
/* Jump to next block and read its header. */
static int
jump_block (struct grub_lzopio *lzopio)
{
/* only jump if block was not decompressed (and read from disk) */
if (!lzopio->block.udata)
{
grub_off_t off = grub_file_tell (lzopio->file) + lzopio->block.csize;
if (grub_file_seek (lzopio->file, off) == ((grub_off_t) - 1))
return -1;
}
return read_block_header (lzopio);
}
static int
calculate_uncompressed_size (grub_file_t file)
{
grub_lzopio_t lzopio = file->data;
grub_off_t usize_total = 0;
if (read_block_header (lzopio) < 0)
return -1;
/* FIXME: Don't do this for not easily seekable files. */
while (lzopio->block.usize != 0)
{
usize_total += lzopio->block.usize;
if (jump_block (lzopio) < 0)
return -1;
}
file->size = usize_total;
return 0;
}
struct lzop_header
{
grub_uint8_t magic[LZOP_MAGIC_SIZE];
grub_uint16_t lzop_version;
grub_uint16_t lib_version;
grub_uint16_t lib_version_ext;
grub_uint8_t method;
grub_uint8_t level;
grub_uint32_t flags;
/* grub_uint32_t filter; */ /* No filters support. Rarely used anyway. */
grub_uint32_t mode;
grub_uint32_t mtime_lo;
grub_uint32_t mtime_hi;
grub_uint8_t name_len;
} __attribute__ ((packed));
static int
test_header (grub_file_t file)
{
grub_lzopio_t lzopio = file->data;
struct lzop_header header;
grub_uint32_t flags, checksum;
const gcry_md_spec_t *hcheck;
grub_uint8_t *context = NULL;
grub_uint8_t *name = NULL;
if (grub_file_read (lzopio->file, &header, sizeof (header)) != sizeof (header))
return 0;
if (grub_memcmp (header.magic, LZOP_MAGIC, LZOP_MAGIC_SIZE) != 0)
return 0;
if (grub_be_to_cpu16(header.lib_version) < LZOP_NEW_LIB)
return 0;
/* Too new version, should upgrade minilzo? */
if (grub_be_to_cpu16 (header.lib_version_ext) > MINILZO_VERSION)
return 0;
flags = grub_be_to_cpu32 (header.flags);
if (flags & F_CRC32_D)
{
lzopio->has_ucheck = 1;
lzopio->ucheck_fun = grub_crypto_lookup_md_by_name ("crc32");
}
else if (flags & F_ADLER32_D)
{
lzopio->has_ucheck = 1;
lzopio->ucheck_fun = grub_crypto_lookup_md_by_name ("adler32");
}
if (flags & F_CRC32_C)
{
lzopio->has_ccheck = 1;
lzopio->ccheck_fun = grub_crypto_lookup_md_by_name ("crc32");
}
else if (flags & F_ADLER32_C)
{
lzopio->has_ccheck = 1;
lzopio->ccheck_fun = grub_crypto_lookup_md_by_name ("adler32");
}
if (flags & F_H_CRC32)
hcheck = grub_crypto_lookup_md_by_name ("crc32");
else
hcheck = grub_crypto_lookup_md_by_name ("adler32");
if (hcheck) {
context = grub_malloc(hcheck->contextsize);
if (! context)
return 0;
hcheck->init(context);
/* MAGIC is not included in check calculation. */
hcheck->write(context, &header.lzop_version, sizeof(header)- LZOP_MAGIC_SIZE);
}
if (header.name_len != 0)
{
name = grub_malloc (header.name_len);
if (! name)
{
grub_free (context);
return 0;
}
if (grub_file_read (lzopio->file, name, header.name_len) !=
header.name_len)
{
grub_free(name);
goto CORRUPTED;
}
if (hcheck)
hcheck->write(context, name, header.name_len);
grub_free(name);
}
if (hcheck)
hcheck->final(context);
if (grub_file_read (lzopio->file, &checksum, sizeof (checksum)) !=
sizeof (checksum))
goto CORRUPTED;
if (hcheck && grub_memcmp (&checksum, hcheck->read(context), sizeof(checksum)) != 0)
goto CORRUPTED;
lzopio->start_block_off = grub_file_tell (lzopio->file);
if (calculate_uncompressed_size (file) < 0)
goto CORRUPTED;
/* Get back to start block. */
grub_file_seek (lzopio->file, lzopio->start_block_off);
/* Read first block - grub_lzopio_read() expects valid block. */
if (read_block_header (lzopio) < 0)
goto CORRUPTED;
lzopio->saved_off = 0;
return 1;
CORRUPTED:
grub_free(name);
return 0;
}
static grub_file_t
grub_lzopio_open (grub_file_t io,
const char *name __attribute__ ((unused)))
{
grub_file_t file;
grub_lzopio_t lzopio;
file = (grub_file_t) grub_zalloc (sizeof (*file));
if (!file)
return 0;
lzopio = grub_zalloc (sizeof (*lzopio));
if (!lzopio)
{
grub_free (file);
return 0;
}
lzopio->file = io;
file->device = io->device;
file->data = lzopio;
file->fs = &grub_lzopio_fs;
file->size = GRUB_FILE_SIZE_UNKNOWN;
file->not_easily_seekable = 1;
if (grub_file_tell (lzopio->file) != 0)
grub_file_seek (lzopio->file, 0);
if (!test_header (file))
{
grub_errno = GRUB_ERR_NONE;
grub_file_seek (io, 0);
grub_free (lzopio);
grub_free (file);
return io;
}
return file;
}
static grub_ssize_t
grub_lzopio_read (grub_file_t file, char *buf, grub_size_t len)
{
grub_lzopio_t lzopio = file->data;
grub_ssize_t ret = 0;
grub_off_t off;
/* Backward seek before last read block. */
if (lzopio->saved_off > grub_file_tell (file))
{
grub_file_seek (lzopio->file, lzopio->start_block_off);
if (read_block_header (lzopio) < 0)
goto CORRUPTED;
lzopio->saved_off = 0;
}
/* Forward to first block with requested data. */
while (lzopio->saved_off + lzopio->block.usize <= grub_file_tell (file))
{
/* EOF, could be possible files with unknown size. */
if (lzopio->block.usize == 0)
return 0;
if (jump_block (lzopio) < 0)
goto CORRUPTED;
}
off = grub_file_tell (file) - lzopio->saved_off;
while (len != 0 && lzopio->block.usize != 0)
{
grub_size_t to_copy;
/* Block not decompressed yet. */
if (!lzopio->block.udata && uncompress_block (lzopio) < 0)
goto CORRUPTED;
/* Copy requested data into buffer. */
to_copy = lzopio->block.usize - off;
if (to_copy > len)
to_copy = len;
grub_memcpy (buf, lzopio->block.udata + off, to_copy);
len -= to_copy;
buf += to_copy;
ret += to_copy;
off = 0;
/* Read next block if needed. */
if (len > 0 && read_block_header (lzopio) < 0)
goto CORRUPTED;
}
return ret;
CORRUPTED:
2012-02-12 14:25:25 +00:00
grub_error (GRUB_ERR_BAD_COMPRESSED_DATA, N_("lzop file corrupted"));
return -1;
}
/* Release everything, including the underlying file object. */
static grub_err_t
grub_lzopio_close (grub_file_t file)
{
grub_lzopio_t lzopio = file->data;
grub_file_close (lzopio->file);
grub_free (lzopio->block.cdata);
grub_free (lzopio->block.udata);
grub_free (lzopio);
/* Device must not be closed twice. */
file->device = 0;
return grub_errno;
}
static struct grub_fs grub_lzopio_fs = {
.name = "lzopio",
.dir = 0,
.open = 0,
.read = grub_lzopio_read,
.close = grub_lzopio_close,
.label = 0,
.next = 0
};
GRUB_MOD_INIT (lzopio)
{
grub_file_filter_register (GRUB_FILE_FILTER_LZOPIO, grub_lzopio_open);
}
GRUB_MOD_FINI (lzopio)
{
grub_file_filter_unregister (GRUB_FILE_FILTER_LZOPIO);
}