297 строки
6.3 KiB
C
297 строки
6.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* LZO1X Decompressor from LZO
|
|
*
|
|
* Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>
|
|
*
|
|
* The full LZO package can be found at:
|
|
* http://www.oberhumer.com/opensource/lzo/
|
|
*
|
|
* Changed for Linux kernel use by:
|
|
* Nitin Gupta <nitingupta910@gmail.com>
|
|
* Richard Purdie <rpurdie@openedhand.com>
|
|
*/
|
|
|
|
#ifndef STATIC
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#endif
|
|
#include <asm/unaligned.h>
|
|
#include <linux/lzo.h>
|
|
#include "lzodefs.h"
|
|
|
|
#define HAVE_IP(x) ((size_t)(ip_end - ip) >= (size_t)(x))
|
|
#define HAVE_OP(x) ((size_t)(op_end - op) >= (size_t)(x))
|
|
#define NEED_IP(x) if (!HAVE_IP(x)) goto input_overrun
|
|
#define NEED_OP(x) if (!HAVE_OP(x)) goto output_overrun
|
|
#define TEST_LB(m_pos) if ((m_pos) < out) goto lookbehind_overrun
|
|
|
|
/* This MAX_255_COUNT is the maximum number of times we can add 255 to a base
|
|
* count without overflowing an integer. The multiply will overflow when
|
|
* multiplying 255 by more than MAXINT/255. The sum will overflow earlier
|
|
* depending on the base count. Since the base count is taken from a u8
|
|
* and a few bits, it is safe to assume that it will always be lower than
|
|
* or equal to 2*255, thus we can always prevent any overflow by accepting
|
|
* two less 255 steps. See Documentation/lzo.txt for more information.
|
|
*/
|
|
#define MAX_255_COUNT ((((size_t)~0) / 255) - 2)
|
|
|
|
int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
|
|
unsigned char *out, size_t *out_len)
|
|
{
|
|
unsigned char *op;
|
|
const unsigned char *ip;
|
|
size_t t, next;
|
|
size_t state = 0;
|
|
const unsigned char *m_pos;
|
|
const unsigned char * const ip_end = in + in_len;
|
|
unsigned char * const op_end = out + *out_len;
|
|
|
|
unsigned char bitstream_version;
|
|
|
|
op = out;
|
|
ip = in;
|
|
|
|
if (unlikely(in_len < 3))
|
|
goto input_overrun;
|
|
|
|
if (likely(in_len >= 5) && likely(*ip == 17)) {
|
|
bitstream_version = ip[1];
|
|
ip += 2;
|
|
} else {
|
|
bitstream_version = 0;
|
|
}
|
|
|
|
if (*ip > 17) {
|
|
t = *ip++ - 17;
|
|
if (t < 4) {
|
|
next = t;
|
|
goto match_next;
|
|
}
|
|
goto copy_literal_run;
|
|
}
|
|
|
|
for (;;) {
|
|
t = *ip++;
|
|
if (t < 16) {
|
|
if (likely(state == 0)) {
|
|
if (unlikely(t == 0)) {
|
|
size_t offset;
|
|
const unsigned char *ip_last = ip;
|
|
|
|
while (unlikely(*ip == 0)) {
|
|
ip++;
|
|
NEED_IP(1);
|
|
}
|
|
offset = ip - ip_last;
|
|
if (unlikely(offset > MAX_255_COUNT))
|
|
return LZO_E_ERROR;
|
|
|
|
offset = (offset << 8) - offset;
|
|
t += offset + 15 + *ip++;
|
|
}
|
|
t += 3;
|
|
copy_literal_run:
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
|
if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) {
|
|
const unsigned char *ie = ip + t;
|
|
unsigned char *oe = op + t;
|
|
do {
|
|
COPY8(op, ip);
|
|
op += 8;
|
|
ip += 8;
|
|
COPY8(op, ip);
|
|
op += 8;
|
|
ip += 8;
|
|
} while (ip < ie);
|
|
ip = ie;
|
|
op = oe;
|
|
} else
|
|
#endif
|
|
{
|
|
NEED_OP(t);
|
|
NEED_IP(t + 3);
|
|
do {
|
|
*op++ = *ip++;
|
|
} while (--t > 0);
|
|
}
|
|
state = 4;
|
|
continue;
|
|
} else if (state != 4) {
|
|
next = t & 3;
|
|
m_pos = op - 1;
|
|
m_pos -= t >> 2;
|
|
m_pos -= *ip++ << 2;
|
|
TEST_LB(m_pos);
|
|
NEED_OP(2);
|
|
op[0] = m_pos[0];
|
|
op[1] = m_pos[1];
|
|
op += 2;
|
|
goto match_next;
|
|
} else {
|
|
next = t & 3;
|
|
m_pos = op - (1 + M2_MAX_OFFSET);
|
|
m_pos -= t >> 2;
|
|
m_pos -= *ip++ << 2;
|
|
t = 3;
|
|
}
|
|
} else if (t >= 64) {
|
|
next = t & 3;
|
|
m_pos = op - 1;
|
|
m_pos -= (t >> 2) & 7;
|
|
m_pos -= *ip++ << 3;
|
|
t = (t >> 5) - 1 + (3 - 1);
|
|
} else if (t >= 32) {
|
|
t = (t & 31) + (3 - 1);
|
|
if (unlikely(t == 2)) {
|
|
size_t offset;
|
|
const unsigned char *ip_last = ip;
|
|
|
|
while (unlikely(*ip == 0)) {
|
|
ip++;
|
|
NEED_IP(1);
|
|
}
|
|
offset = ip - ip_last;
|
|
if (unlikely(offset > MAX_255_COUNT))
|
|
return LZO_E_ERROR;
|
|
|
|
offset = (offset << 8) - offset;
|
|
t += offset + 31 + *ip++;
|
|
NEED_IP(2);
|
|
}
|
|
m_pos = op - 1;
|
|
next = get_unaligned_le16(ip);
|
|
ip += 2;
|
|
m_pos -= next >> 2;
|
|
next &= 3;
|
|
} else {
|
|
NEED_IP(2);
|
|
next = get_unaligned_le16(ip);
|
|
if (((next & 0xfffc) == 0xfffc) &&
|
|
((t & 0xf8) == 0x18) &&
|
|
likely(bitstream_version)) {
|
|
NEED_IP(3);
|
|
t &= 7;
|
|
t |= ip[2] << 3;
|
|
t += MIN_ZERO_RUN_LENGTH;
|
|
NEED_OP(t);
|
|
memset(op, 0, t);
|
|
op += t;
|
|
next &= 3;
|
|
ip += 3;
|
|
goto match_next;
|
|
} else {
|
|
m_pos = op;
|
|
m_pos -= (t & 8) << 11;
|
|
t = (t & 7) + (3 - 1);
|
|
if (unlikely(t == 2)) {
|
|
size_t offset;
|
|
const unsigned char *ip_last = ip;
|
|
|
|
while (unlikely(*ip == 0)) {
|
|
ip++;
|
|
NEED_IP(1);
|
|
}
|
|
offset = ip - ip_last;
|
|
if (unlikely(offset > MAX_255_COUNT))
|
|
return LZO_E_ERROR;
|
|
|
|
offset = (offset << 8) - offset;
|
|
t += offset + 7 + *ip++;
|
|
NEED_IP(2);
|
|
next = get_unaligned_le16(ip);
|
|
}
|
|
ip += 2;
|
|
m_pos -= next >> 2;
|
|
next &= 3;
|
|
if (m_pos == op)
|
|
goto eof_found;
|
|
m_pos -= 0x4000;
|
|
}
|
|
}
|
|
TEST_LB(m_pos);
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
|
if (op - m_pos >= 8) {
|
|
unsigned char *oe = op + t;
|
|
if (likely(HAVE_OP(t + 15))) {
|
|
do {
|
|
COPY8(op, m_pos);
|
|
op += 8;
|
|
m_pos += 8;
|
|
COPY8(op, m_pos);
|
|
op += 8;
|
|
m_pos += 8;
|
|
} while (op < oe);
|
|
op = oe;
|
|
if (HAVE_IP(6)) {
|
|
state = next;
|
|
COPY4(op, ip);
|
|
op += next;
|
|
ip += next;
|
|
continue;
|
|
}
|
|
} else {
|
|
NEED_OP(t);
|
|
do {
|
|
*op++ = *m_pos++;
|
|
} while (op < oe);
|
|
}
|
|
} else
|
|
#endif
|
|
{
|
|
unsigned char *oe = op + t;
|
|
NEED_OP(t);
|
|
op[0] = m_pos[0];
|
|
op[1] = m_pos[1];
|
|
op += 2;
|
|
m_pos += 2;
|
|
do {
|
|
*op++ = *m_pos++;
|
|
} while (op < oe);
|
|
}
|
|
match_next:
|
|
state = next;
|
|
t = next;
|
|
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
|
|
if (likely(HAVE_IP(6) && HAVE_OP(4))) {
|
|
COPY4(op, ip);
|
|
op += t;
|
|
ip += t;
|
|
} else
|
|
#endif
|
|
{
|
|
NEED_IP(t + 3);
|
|
NEED_OP(t);
|
|
while (t > 0) {
|
|
*op++ = *ip++;
|
|
t--;
|
|
}
|
|
}
|
|
}
|
|
|
|
eof_found:
|
|
*out_len = op - out;
|
|
return (t != 3 ? LZO_E_ERROR :
|
|
ip == ip_end ? LZO_E_OK :
|
|
ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN);
|
|
|
|
input_overrun:
|
|
*out_len = op - out;
|
|
return LZO_E_INPUT_OVERRUN;
|
|
|
|
output_overrun:
|
|
*out_len = op - out;
|
|
return LZO_E_OUTPUT_OVERRUN;
|
|
|
|
lookbehind_overrun:
|
|
*out_len = op - out;
|
|
return LZO_E_LOOKBEHIND_OVERRUN;
|
|
}
|
|
#ifndef STATIC
|
|
EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("LZO1X Decompressor");
|
|
|
|
#endif
|