/*
* LZO1X Decompressor from MiniLZO
*
* Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com>
*
* The full LZO package can be found at:
* http://www.oberhumer.com/opensource/lzo/
*
* Changed for kernel use by:
* Nitin Gupta <nitingupta910@gmail.com>
* Richard Purdie <rpurdie@openedhand.com>
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/lzo.h>
#include <asm/byteorder.h>
#include <asm/unaligned.h>
#include "lzodefs.h"
#define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x))
#define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x))
#define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op)
#define COPY4(dst, src) \
put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst))
int lzo1x_decompress_safe(const unsigned char *in, size_t in_len,
unsigned char *out, size_t *out_len)
{
const unsigned char * const ip_end = in + in_len;
unsigned char * const op_end = out + *out_len;
const unsigned char *ip = in, *m_pos;
unsigned char *op = out;
size_t t;
*out_len = 0;
if (*ip > 17) {
t = *ip++ - 17;
if (t < 4)
goto match_next;
if (HAVE_OP(t, op_end, op))
goto output_overrun;
if (HAVE_IP(t + 1, ip_end, ip))
goto input_overrun;
do {
*op++ = *ip++;
} while (--t > 0);
goto first_literal_run;
}
while ((ip < ip_end)) {
t = *ip++;
if (t >= 16)
goto match;
if (t == 0) {
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
while (*ip == 0) {
t += 255;
ip++;
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
}
t += 15 + *ip++;
}
if (HAVE_OP(t + 3, op_end, op))
goto output_overrun;
if (HAVE_IP(t + 4, ip_end, ip))
goto input_overrun;
COPY4(op, ip);
op += 4;
ip += 4;
if (--t > 0) {
if (t >= 4) {
do {
COPY4(op, ip);
op += 4;
ip += 4;
t -= 4;
} while (t >= 4);
if (t > 0) {
do {
*op++ = *ip++;
} while (--t > 0);
}
} else {
do {
*op++ = *ip++;
} while (--t > 0);
}
}
first_literal_run:
t = *ip++;
if (t >= 16)
goto match;
m_pos = op - (1 + M2_MAX_OFFSET);
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
if (HAVE_LB(m_pos, out, op))
goto lookbehind_overrun;
if (HAVE_OP(3, op_end, op))
goto output_overrun;
*op++ = *m_pos++;
*op++ = *m_pos++;
*op++ = *m_pos;
goto match_done;
do {
match:
if (t >= 64) {
m_pos = op - 1;
m_pos -= (t >> 2) & 7;
m_pos -= *ip++ << 3;
t = (t >> 5) - 1;
if (HAVE_LB(m_pos, out, op))
goto lookbehind_overrun;
if (HAVE_OP(t + 3 - 1, op_end, op))
goto output_overrun;
goto copy_match;
} else if (t >= 32) {
t &= 31;
if (t == 0) {
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
while (*ip == 0) {
t += 255;
ip++;
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
}
t += 31 + *ip++;
}
m_pos = op - 1;
m_pos -= get_unaligned_le16(ip) >> 2;
ip += 2;
} else if (t >= 16) {
m_pos = op;
m_pos -= (t & 8) << 11;
t &= 7;
if (t == 0) {
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
while (*ip == 0) {
t += 255;
ip++;
if (HAVE_IP(1, ip_end, ip))
goto input_overrun;
}
t += 7 + *ip++;
}
m_pos -= get_unaligned_le16(ip) >> 2;
ip += 2;
if (m_pos == op)
goto eof_found;
m_pos -= 0x4000;
} else {
m_pos = op - 1;
m_pos -= t >> 2;
m_pos -= *ip++ << 2;
if (HAVE_LB(m_pos, out, op))
goto lookbehind_overrun;
if (HAVE_OP(2, op_end, op))
goto output_overrun;
*op++ = *m_pos++;
*op++ = *m_pos;
goto match_done;
}
if (HAVE_LB(m_pos, out, op))
goto lookbehind_overrun;
if (HAVE_OP(t + 3 - 1, op_end, op))
goto output_overrun;
if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
COPY4(op, m_pos);
op += 4;
m_pos += 4;
t -= 4 - (3 - 1);
do {
COPY4(op, m_pos);
op += 4;
m_pos += 4;
t -= 4;
} while (t >= 4);
if (t > 0)
do {
*op++ = *m_pos++;
} while (--t > 0);
} else {
copy_match:
*op++ = *m_pos++;
*op++ = *m_pos++;
do {
*op++ = *m_pos++;
} while (--t > 0);
}
match_done:
t = ip[-2] & 3;
if (t == 0)
break;
match_next:
if (HAVE_OP(t, op_end, op))
goto output_overrun;
if (HAVE_IP(t + 1, ip_end, ip))
goto input_overrun;
*op++ = *ip++;
if (t > 1) {
*op++ = *ip++;
if (t > 2)
*op++ = *ip++;
}
t = *ip++;
} while (ip < ip_end);
}
*out_len = op - out;
return LZO_E_EOF_NOT_FOUND;
eof_found:
*out_len = op - out;
return (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;
}
EXPORT_SYMBOL_GPL(lzo1x_decompress_safe);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("LZO1X Decompressor");