lib/lz4/lz4_decompress.c - kernel/lockdown - Git at Google

 /*
  * LZ4 Decompressor for Linux kernel
  *
  * Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
  *
  * Based on LZ4 implementation by Yann Collet.
  *
  * LZ4 - Fast LZ compression algorithm
  * Copyright (C) 2011-2012, Yann Collet.
  * BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  *  You can contact the author at :
  *  - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
  *  - LZ4 source repository : http://code.google.com/p/lz4/
  */

 #ifndef STATIC
 #include <linux/module.h>
 #include <linux/kernel.h>
 #endif
 #include <linux/lz4.h>

 #include <asm/unaligned.h>

 #include "lz4defs.h"

 static int lz4_uncompress(const char *source, char *dest, int osize)
 {
 	const BYTE *ip = (const BYTE *) source;
 	const BYTE *ref;
 	BYTE *op = (BYTE *) dest;
 	BYTE * const oend = op + osize;
 	BYTE *cpy;
 	unsigned token;
 	size_t length;
 	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
 #if LZ4_ARCH64
 	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
 #endif

 	while (1) {

 		/* get runlength */
 		token = *ip++;
 		length = (token >> ML_BITS);
 		if (length == RUN_MASK) {
 			size_t len;

 			len = *ip++;
 			for (; len == 255; length += 255)
 				len = *ip++;
 			if (unlikely(length > (size_t)(length + len)))
 				goto _output_error;
 			length += len;
 		}

 		/* copy literals */
 		cpy = op + length;
 		if (unlikely(cpy > oend - COPYLENGTH)) {
 			/*
 			 * Error: not enough place for another match
 			 * (min 4) + 5 literals
 			 */
 			if (cpy != oend)
 				goto _output_error;

 			memcpy(op, ip, length);
 			ip += length;
 			break; /* EOF */
 		}
 		LZ4_WILDCOPY(ip, op, cpy);
 		ip -= (op - cpy);
 		op = cpy;

 		/* get offset */
 		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
 		ip += 2;

 		/* Error: offset create reference outside destination buffer */
 		if (unlikely(ref < (BYTE *const) dest))
 			goto _output_error;

 		/* get matchlength */
 		length = token & ML_MASK;
 		if (length == ML_MASK) {
 			for (; *ip == 255; length += 255)
 				ip++;
 			if (unlikely(length > (size_t)(length + *ip)))
 				goto _output_error;
 			length += *ip++;
 		}

 		/* copy repeated sequence */
 		if (unlikely((op - ref) < STEPSIZE)) {
 #if LZ4_ARCH64
 			size_t dec64 = dec64table[op - ref];
 #else
 			const int dec64 = 0;
 #endif
 			op[0] = ref[0];
 			op[1] = ref[1];
 			op[2] = ref[2];
 			op[3] = ref[3];
 			op += 4;
 			ref += 4;
 			ref -= dec32table[op-ref];
 			PUT4(ref, op);
 			op += STEPSIZE - 4;
 			ref -= dec64;
 		} else {
 			LZ4_COPYSTEP(ref, op);
 		}
 		cpy = op + length - (STEPSIZE - 4);
 		if (cpy > (oend - COPYLENGTH)) {

 			/* Error: request to write beyond destination buffer */
 			if (cpy > oend)
 				goto _output_error;
 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
 				*op++ = *ref++;
 			op = cpy;
 			/*
 			 * Check EOF (should never happen, since last 5 bytes
 			 * are supposed to be literals)
 			 */
 			if (op == oend)
 				goto _output_error;
 			continue;
 		}
 		LZ4_SECURECOPY(ref, op, cpy);
 		op = cpy; /* correction */
 	}
 	/* end of decoding */
 	return (int) (((char *)ip) - source);

 	/* write overflow error detected */
 _output_error:
 	return -1;
 }

 static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
 				int isize, size_t maxoutputsize)
 {
 	const BYTE *ip = (const BYTE *) source;
 	const BYTE *const iend = ip + isize;
 	const BYTE *ref;


 	BYTE *op = (BYTE *) dest;
 	BYTE * const oend = op + maxoutputsize;
 	BYTE *cpy;

 	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
 #if LZ4_ARCH64
 	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
 #endif

 	/* Main Loop */
 	while (ip < iend) {

 		unsigned token;
 		size_t length;

 		/* get runlength */
 		token = *ip++;
 		length = (token >> ML_BITS);
 		if (length == RUN_MASK) {
 			int s = 255;
 			while ((ip < iend) && (s == 255)) {
 				s = *ip++;
 				if (unlikely(length > (size_t)(length + s)))
 					goto _output_error;
 				length += s;
 			}
 		}
 		/* copy literals */
 		cpy = op + length;
 		if ((cpy > oend - COPYLENGTH) ||
 			(ip + length > iend - COPYLENGTH)) {

 			if (cpy > oend)
 				goto _output_error;/* writes beyond buffer */

 			if (ip + length != iend)
 				goto _output_error;/*
 						    * Error: LZ4 format requires
 						    * to consume all input
 						    * at this stage
 						    */
 			memcpy(op, ip, length);
 			op += length;
 			break;/* Necessarily EOF, due to parsing restrictions */
 		}
 		LZ4_WILDCOPY(ip, op, cpy);
 		ip -= (op - cpy);
 		op = cpy;

 		/* get offset */
 		LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
 		ip += 2;
 		if (ref < (BYTE * const) dest)
 			goto _output_error;
 			/*
 			 * Error : offset creates reference
 			 * outside of destination buffer
 			 */

 		/* get matchlength */
 		length = (token & ML_MASK);
 		if (length == ML_MASK) {
 			while (ip < iend) {
 				int s = *ip++;
 				if (unlikely(length > (size_t)(length + s)))
 					goto _output_error;
 				length += s;
 				if (s == 255)
 					continue;
 				break;
 			}
 		}

 		/* copy repeated sequence */
 		if (unlikely((op - ref) < STEPSIZE)) {
 #if LZ4_ARCH64
 			size_t dec64 = dec64table[op - ref];
 #else
 			const int dec64 = 0;
 #endif
 				op[0] = ref[0];
 				op[1] = ref[1];
 				op[2] = ref[2];
 				op[3] = ref[3];
 				op += 4;
 				ref += 4;
 				ref -= dec32table[op - ref];
 				PUT4(ref, op);
 				op += STEPSIZE - 4;
 				ref -= dec64;
 		} else {
 			LZ4_COPYSTEP(ref, op);
 		}
 		cpy = op + length - (STEPSIZE-4);
 		if (cpy > oend - COPYLENGTH) {
 			if (cpy > oend)
 				goto _output_error; /* write outside of buf */

 			LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
 			while (op < cpy)
 				*op++ = *ref++;
 			op = cpy;
 			/*
 			 * Check EOF (should never happen, since last 5 bytes
 			 * are supposed to be literals)
 			 */
 			if (op == oend)
 				goto _output_error;
 			continue;
 		}
 		LZ4_SECURECOPY(ref, op, cpy);
 		op = cpy; /* correction */
 	}
 	/* end of decoding */
 	return (int) (((char *) op) - dest);

 	/* write overflow error detected */
 _output_error:
 	return -1;
 }

 int lz4_decompress(const unsigned char *src, size_t *src_len,
 		unsigned char *dest, size_t actual_dest_len)
 {
 	int ret = -1;
 	int input_len = 0;

 	input_len = lz4_uncompress(src, dest, actual_dest_len);
 	if (input_len < 0)
 		goto exit_0;
 	*src_len = input_len;

 	return 0;
 exit_0:
 	return ret;
 }
 #ifndef STATIC
 EXPORT_SYMBOL(lz4_decompress);
 #endif

 int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
 		unsigned char *dest, size_t *dest_len)
 {
 	int ret = -1;
 	int out_len = 0;

 	out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
 					*dest_len);
 	if (out_len < 0)
 		goto exit_0;
 	*dest_len = out_len;

 	return 0;
 exit_0:
 	return ret;
 }
 #ifndef STATIC
 EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);

 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("LZ4 Decompressor");
 #endif
	/*
	* LZ4 Decompressor for Linux kernel
	*
	* Copyright (C) 2013, LG Electronics, Kyungsik Lee <kyungsik.lee@lge.com>
	*
	* Based on LZ4 implementation by Yann Collet.
	*
	* LZ4 - Fast LZ compression algorithm
	* Copyright (C) 2011-2012, Yann Collet.
	* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions are
	* met:
	*
	* * Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* * Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*
	* You can contact the author at :
	* - LZ4 homepage : http://fastcompression.blogspot.com/p/lz4.html
	* - LZ4 source repository : http://code.google.com/p/lz4/
	*/

	#ifndef STATIC
	#include <linux/module.h>
	#include <linux/kernel.h>
	#endif
	#include <linux/lz4.h>

	#include <asm/unaligned.h>

	#include "lz4defs.h"

	static int lz4_uncompress(const char source, char dest, int osize)
	{
	const BYTE ip = (const BYTE ) source;
	const BYTE *ref;
	BYTE op = (BYTE ) dest;
	BYTE * const oend = op + osize;
	BYTE *cpy;
	unsigned token;
	size_t length;
	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
	#if LZ4_ARCH64
	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
	#endif

	while (1) {

	/* get runlength */
	token = *ip++;
	length = (token >> ML_BITS);
	if (length == RUN_MASK) {
	size_t len;

	len = *ip++;
	for (; len == 255; length += 255)
	len = *ip++;
	if (unlikely(length > (size_t)(length + len)))
	goto _output_error;
	length += len;
	}

	/* copy literals */
	cpy = op + length;
	if (unlikely(cpy > oend - COPYLENGTH)) {
	/*
	* Error: not enough place for another match
	* (min 4) + 5 literals
	*/
	if (cpy != oend)
	goto _output_error;

	memcpy(op, ip, length);
	ip += length;
	break; /* EOF */
	}
	LZ4_WILDCOPY(ip, op, cpy);
	ip -= (op - cpy);
	op = cpy;

	/* get offset */
	LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
	ip += 2;

	/* Error: offset create reference outside destination buffer */
	if (unlikely(ref < (BYTE *const) dest))
	goto _output_error;

	/* get matchlength */
	length = token & ML_MASK;
	if (length == ML_MASK) {
	for (; *ip == 255; length += 255)
	ip++;
	if (unlikely(length > (size_t)(length + *ip)))
	goto _output_error;
	length += *ip++;
	}

	/* copy repeated sequence */
	if (unlikely((op - ref) < STEPSIZE)) {
	#if LZ4_ARCH64
	size_t dec64 = dec64table[op - ref];
	#else
	const int dec64 = 0;
	#endif
	op[0] = ref[0];
	op[1] = ref[1];
	op[2] = ref[2];
	op[3] = ref[3];
	op += 4;
	ref += 4;
	ref -= dec32table[op-ref];
	PUT4(ref, op);
	op += STEPSIZE - 4;
	ref -= dec64;
	} else {
	LZ4_COPYSTEP(ref, op);
	}
	cpy = op + length - (STEPSIZE - 4);
	if (cpy > (oend - COPYLENGTH)) {

	/* Error: request to write beyond destination buffer */
	if (cpy > oend)
	goto _output_error;
	LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
	while (op < cpy)
	op++ = ref++;
	op = cpy;
	/*
	* Check EOF (should never happen, since last 5 bytes
	* are supposed to be literals)
	*/
	if (op == oend)
	goto _output_error;
	continue;
	}
	LZ4_SECURECOPY(ref, op, cpy);
	op = cpy; /* correction */
	}
	/* end of decoding */
	return (int) (((char *)ip) - source);

	/* write overflow error detected */
	_output_error:
	return -1;
	}

	static int lz4_uncompress_unknownoutputsize(const char source, char dest,
	int isize, size_t maxoutputsize)
	{
	const BYTE ip = (const BYTE ) source;
	const BYTE *const iend = ip + isize;
	const BYTE *ref;


	BYTE op = (BYTE ) dest;
	BYTE * const oend = op + maxoutputsize;
	BYTE *cpy;

	size_t dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
	#if LZ4_ARCH64
	size_t dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
	#endif

	/* Main Loop */
	while (ip < iend) {

	unsigned token;
	size_t length;

	/* get runlength */
	token = *ip++;
	length = (token >> ML_BITS);
	if (length == RUN_MASK) {
	int s = 255;
	while ((ip < iend) && (s == 255)) {
	s = *ip++;
	if (unlikely(length > (size_t)(length + s)))
	goto _output_error;
	length += s;
	}
	}
	/* copy literals */
	cpy = op + length;
	if ((cpy > oend - COPYLENGTH) \|\|
	(ip + length > iend - COPYLENGTH)) {

	if (cpy > oend)
	goto _output_error;/* writes beyond buffer */

	if (ip + length != iend)
	goto _output_error;/*
	* Error: LZ4 format requires
	* to consume all input
	* at this stage
	*/
	memcpy(op, ip, length);
	op += length;
	break;/* Necessarily EOF, due to parsing restrictions */
	}
	LZ4_WILDCOPY(ip, op, cpy);
	ip -= (op - cpy);
	op = cpy;

	/* get offset */
	LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
	ip += 2;
	if (ref < (BYTE * const) dest)
	goto _output_error;
	/*
	* Error : offset creates reference
	* outside of destination buffer
	*/

	/* get matchlength */
	length = (token & ML_MASK);
	if (length == ML_MASK) {
	while (ip < iend) {
	int s = *ip++;
	if (unlikely(length > (size_t)(length + s)))
	goto _output_error;
	length += s;
	if (s == 255)
	continue;
	break;
	}
	}

	/* copy repeated sequence */
	if (unlikely((op - ref) < STEPSIZE)) {
	#if LZ4_ARCH64
	size_t dec64 = dec64table[op - ref];
	#else
	const int dec64 = 0;
	#endif
	op[0] = ref[0];
	op[1] = ref[1];
	op[2] = ref[2];
	op[3] = ref[3];
	op += 4;
	ref += 4;
	ref -= dec32table[op - ref];
	PUT4(ref, op);
	op += STEPSIZE - 4;
	ref -= dec64;
	} else {
	LZ4_COPYSTEP(ref, op);
	}
	cpy = op + length - (STEPSIZE-4);
	if (cpy > oend - COPYLENGTH) {
	if (cpy > oend)
	goto _output_error; /* write outside of buf */

	LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
	while (op < cpy)
	op++ = ref++;
	op = cpy;
	/*
	* Check EOF (should never happen, since last 5 bytes
	* are supposed to be literals)
	*/
	if (op == oend)
	goto _output_error;
	continue;
	}
	LZ4_SECURECOPY(ref, op, cpy);
	op = cpy; /* correction */
	}
	/* end of decoding */
	return (int) (((char *) op) - dest);

	/* write overflow error detected */
	_output_error:
	return -1;
	}

	int lz4_decompress(const unsigned char src, size_t src_len,
	unsigned char *dest, size_t actual_dest_len)
	{
	int ret = -1;
	int input_len = 0;

	input_len = lz4_uncompress(src, dest, actual_dest_len);
	if (input_len < 0)
	goto exit_0;
	*src_len = input_len;

	return 0;
	exit_0:
	return ret;
	}
	#ifndef STATIC
	EXPORT_SYMBOL(lz4_decompress);
	#endif

	int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
	unsigned char dest, size_t dest_len)
	{
	int ret = -1;
	int out_len = 0;

	out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
	*dest_len);
	if (out_len < 0)
	goto exit_0;
	*dest_len = out_len;

	return 0;
	exit_0:
	return ret;
	}
	#ifndef STATIC
	EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);

	MODULE_LICENSE("Dual BSD/GPL");
	MODULE_DESCRIPTION("LZ4 Decompressor");
	#endif