lib/decompress_unlzo.c - linux - Git at Google

 // 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
	// 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