// SPDX-License-Identifier: GPL-2.0-or-later
/*
* LZO decompressor for the Linux kernel. Code borrowed from the lzo
* implementation by Markus Franz Xaver Johannes Oberhumer.
*
* Linux kernel adaptation:
* Copyright (C) 2009
* Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
*
* Original code:
* Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
* All Rights Reserved.
*
* Markus F.X.J. Oberhumer
* <markus@oberhumer.com>
* http://www.oberhumer.com/opensource/lzop/
*/
#ifdef STATIC
#define PREBOOT
#include "lzo/lzo1x_decompress_safe.c"
#else
#include <linux/decompress/unlzo.h>
#endif
#include <linux/types.h>
#include <linux/lzo.h>
#include <linux/decompress/mm.h>
#include <linux/compiler.h>
#include <asm/unaligned.h>
static const unsigned char lzop_magic[] = {
0x89, 0x4c, 0x5a, 0x4f, 0x00, 0x0d, 0x0a, 0x1a, 0x0a };
#define LZO_BLOCK_SIZE (256*1024l)
#define HEADER_HAS_FILTER 0x00000800L
#define HEADER_SIZE_MIN (9 + 7 + 4 + 8 + 1 + 4)
#define HEADER_SIZE_MAX (9 + 7 + 1 + 8 + 8 + 4 + 1 + 255 + 4)
STATIC inline long INIT parse_header(u8 *input, long *skip, long in_len)
{
int l;
u8 *parse = input;
u8 *end = input + in_len;
u16 version;
/*
* Check that there's enough input to possibly have a valid header.
* Then it is possible to parse several fields until the minimum
* size may have been used.
*/
if (in_len < HEADER_SIZE_MIN)
return 0;
/* read magic: 9 first bits */
for (l = 0; l < 9; l++) {
if (*parse++ != lzop_magic[l])
return 0;
}
/* get version (2bytes), skip library version (2),
* 'need to be extracted' version (2) and
* method (1) */
version = get_unaligned_be16(parse);
parse += 7;
if (version >= 0x0940)
parse++;
if (get_unaligned_be32(parse) & HEADER_HAS_FILTER)
parse += 8; /* flags + filter info */
else
parse += 4; /* flags */
/*
* At least mode, mtime_low, filename length, and checksum must
* be left to be parsed. If also mtime_high is present, it's OK
* because the next input buffer check is after reading the
* filename length.
*/
if (end - parse < 8 + 1 + 4)
return 0;
/* skip mode and mtime_low */
parse += 8;
if (version >= 0x0940)
parse += 4; /* skip mtime_high */
l = *parse++;
/* don't care about the file name, and skip checksum */
if (end - parse < l + 4)
return 0;
parse += l + 4;
*skip = parse - input;
return 1;
}
STATIC int INIT unlzo(u8 *input, long in_len,
long (*fill)(void *, unsigned long),
long (*flush)(void *, unsigned long),
u8 *output, long *posp,
void (*error) (char *x))
{
u8 r = 0;
long skip = 0;
u32 src_len, dst_len;
size_t tmp;
u8 *in_buf, *in_buf_save, *out_buf;
int ret = -1;
if (output) {
out_buf = output;
} else if (!flush) {
error("NULL output pointer and no flush function provided");
goto exit;
} else {
out_buf = malloc(LZO_BLOCK_SIZE);
if (!out_buf) {
error("Could not allocate output buffer");
goto exit;
}
}
if (input && fill) {
error("Both input pointer and fill function provided, don't know what to do");
goto exit_1;
} else if (input) {
in_buf = input;
} else if (!fill) {
error("NULL input pointer and missing fill function");
goto exit_1;
} else {
in_buf = malloc(lzo1x_worst_compress(LZO_BLOCK_SIZE));
if (!in_buf) {
error("Could not allocate input buffer");
goto exit_1;
}
}
in_buf_save = in_buf;
if (posp)
*posp = 0;
if (fill) {
/*
* Start from in_buf + HEADER_SIZE_MAX to make it possible
* to use memcpy() to copy the unused data to the beginning
* of the buffer. This way memmove() isn't needed which
* is missing from pre-boot environments of most archs.
*/
in_buf += HEADER_SIZE_MAX;
in_len = fill(in_buf, HEADER_SIZE_MAX);
}
if (!parse_header(in_buf, &skip, in_len)) {
error("invalid header");
goto exit_2;
}
in_buf += skip;
in_len -= skip;
if (fill) {
/* Move the unused data to the beginning of the buffer. */
memcpy(in_buf_save, in_buf, in_len);
in_buf = in_buf_save;
}
if (posp)
*posp = skip;
for (;;) {
/* read uncompressed block size */
if (fill && in_len < 4) {
skip = fill(in_buf + in_len, 4 - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < 4) {
error("file corrupted");
goto exit_2;
}
dst_len = get_unaligned_be32(in_buf);
in_buf += 4;
in_len -= 4;
/* exit if last block */
if (dst_len == 0) {
if (posp)
*posp += 4;
break;
}
if (dst_len > LZO_BLOCK_SIZE) {
error("dest len longer than block size");
goto exit_2;
}
/* read compressed block size, and skip block checksum info */
if (fill && in_len < 8) {
skip = fill(in_buf + in_len, 8 - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < 8) {
error("file corrupted");
goto exit_2;
}
src_len = get_unaligned_be32(in_buf);
in_buf += 8;
in_len -= 8;
if (src_len <= 0 || src_len > dst_len) {
error("file corrupted");
goto exit_2;
}
/* decompress */
if (fill && in_len < src_len) {
skip = fill(in_buf + in_len, src_len - in_len);
if (skip > 0)
in_len += skip;
}
if (in_len < src_len) {
error("file corrupted");
goto exit_2;
}
tmp = dst_len;
/* When the input data is not compressed at all,
* lzo1x_decompress_safe will fail, so call memcpy()
* instead */
if (unlikely(dst_len == src_len))
memcpy(out_buf, in_buf, src_len);
else {
r = lzo1x_decompress_safe((u8 *) in_buf, src_len,
out_buf, &tmp);
if (r != LZO_E_OK || dst_len != tmp) {
error("Compressed data violation");
goto exit_2;
}
}
if (flush && flush(out_buf, dst_len) != dst_len)
goto exit_2;
if (output)
out_buf += dst_len;
if (posp)
*posp += src_len + 12;
in_buf += src_len;
in_len -= src_len;
if (fill) {
/*
* If there happens to still be unused data left in
* in_buf, move it to the beginning of the buffer.
* Use a loop to avoid memmove() dependency.
*/
if (in_len > 0)
for (skip = 0; skip < in_len; ++skip)
in_buf_save[skip] = in_buf[skip];
in_buf = in_buf_save;
}
}
ret = 0;
exit_2:
if (!input)
free(in_buf_save);
exit_1:
if (!output)
free(out_buf);
exit:
return ret;
}
#ifdef PREBOOT
STATIC int INIT __decompress(unsigned char *buf, long len,
long (*fill)(void*, unsigned long),
long (*flush)(void*, unsigned long),
unsigned char *out_buf, long olen,
long *pos,
void (*error)(char *x))
{
return unlzo(buf, len, fill, flush, out_buf, pos, error);
}
#endif
