tor-browser

xz_dec_stream.c (20512B)

---

/*
* .xz Stream decoder
*
* Author: Lasse Collin <lasse.collin@tukaani.org>
*
* This file has been put into the public domain.
* You can do whatever you want with this file.
*/

#include "xz_private.h"
#include "xz_stream.h"

#ifdef XZ_USE_CRC64
#	define IS_CRC64(check_type) ((check_type) == XZ_CHECK_CRC64)
#else
#	define IS_CRC64(check_type) false
#endif

/* Hash used to validate the Index field */
struct xz_dec_hash {
vli_type unpadded;
vli_type uncompressed;
uint32_t crc32;
};

struct xz_dec {
/* Position in dec_main() */
enum {
	SEQ_STREAM_HEADER,
	SEQ_BLOCK_START,
	SEQ_BLOCK_HEADER,
	SEQ_BLOCK_UNCOMPRESS,
	SEQ_BLOCK_PADDING,
	SEQ_BLOCK_CHECK,
	SEQ_INDEX,
	SEQ_INDEX_PADDING,
	SEQ_INDEX_CRC32,
	SEQ_STREAM_FOOTER
} sequence;

/* Position in variable-length integers and Check fields */
uint32_t pos;

/* Variable-length integer decoded by dec_vli() */
vli_type vli;

/* Saved in_pos and out_pos */
size_t in_start;
size_t out_start;

#ifdef XZ_USE_CRC64
/* CRC32 or CRC64 value in Block or CRC32 value in Index */
uint64_t crc;
#else
/* CRC32 value in Block or Index */
uint32_t crc;
#endif

/* Type of the integrity check calculated from uncompressed data */
enum xz_check check_type;

/* Operation mode */
enum xz_mode mode;

/*
 * True if the next call to xz_dec_run() is allowed to return
 * XZ_BUF_ERROR.
 */
bool allow_buf_error;

/* Information stored in Block Header */
struct {
	/*
	 * Value stored in the Compressed Size field, or
	 * VLI_UNKNOWN if Compressed Size is not present.
	 */
	vli_type compressed;

	/*
	 * Value stored in the Uncompressed Size field, or
	 * VLI_UNKNOWN if Uncompressed Size is not present.
	 */
	vli_type uncompressed;

	/* Size of the Block Header field */
	uint32_t size;
} block_header;

/* Information collected when decoding Blocks */
struct {
	/* Observed compressed size of the current Block */
	vli_type compressed;

	/* Observed uncompressed size of the current Block */
	vli_type uncompressed;

	/* Number of Blocks decoded so far */
	vli_type count;

	/*
	 * Hash calculated from the Block sizes. This is used to
	 * validate the Index field.
	 */
	struct xz_dec_hash hash;
} block;

/* Variables needed when verifying the Index field */
struct {
	/* Position in dec_index() */
	enum {
		SEQ_INDEX_COUNT,
		SEQ_INDEX_UNPADDED,
		SEQ_INDEX_UNCOMPRESSED
	} sequence;

	/* Size of the Index in bytes */
	vli_type size;

	/* Number of Records (matches block.count in valid files) */
	vli_type count;

	/*
	 * Hash calculated from the Records (matches block.hash in
	 * valid files).
	 */
	struct xz_dec_hash hash;
} index;

/*
 * Temporary buffer needed to hold Stream Header, Block Header,
 * and Stream Footer. The Block Header is the biggest (1 KiB)
 * so we reserve space according to that. buf[] has to be aligned
 * to a multiple of four bytes; the size_t variables before it
 * should guarantee this.
 */
struct {
	size_t pos;
	size_t size;
	uint8_t buf[1024];
} temp;

struct xz_dec_lzma2 *lzma2;

#ifdef XZ_DEC_BCJ
struct xz_dec_bcj *bcj;
bool bcj_active;
#endif
};

#ifdef XZ_DEC_ANY_CHECK
/* Sizes of the Check field with different Check IDs */
static const uint8_t check_sizes[16] = {
0,
4, 4, 4,
8, 8, 8,
16, 16, 16,
32, 32, 32,
64, 64, 64
};
#endif

/*
* Fill s->temp by copying data starting from b->in[b->in_pos]. Caller
* must have set s->temp.pos to indicate how much data we are supposed
* to copy into s->temp.buf. Return true once s->temp.pos has reached
* s->temp.size.
*/
static bool fill_temp(struct xz_dec *s, struct xz_buf *b)
{
size_t copy_size = min_t(size_t,
		b->in_size - b->in_pos, s->temp.size - s->temp.pos);

memcpy(s->temp.buf + s->temp.pos, b->in + b->in_pos, copy_size);
b->in_pos += copy_size;
s->temp.pos += copy_size;

if (s->temp.pos == s->temp.size) {
	s->temp.pos = 0;
	return true;
}

return false;
}

/* Decode a variable-length integer (little-endian base-128 encoding) */
static enum xz_ret dec_vli(struct xz_dec *s, const uint8_t *in,
		   size_t *in_pos, size_t in_size)
{
uint8_t byte;

if (s->pos == 0)
	s->vli = 0;

while (*in_pos < in_size) {
	byte = in[*in_pos];
	++*in_pos;

	s->vli |= (vli_type)(byte & 0x7F) << s->pos;

	if ((byte & 0x80) == 0) {
		/* Don't allow non-minimal encodings. */
		if (byte == 0 && s->pos != 0)
			return XZ_DATA_ERROR;

		s->pos = 0;
		return XZ_STREAM_END;
	}

	s->pos += 7;
	if (s->pos == 7 * VLI_BYTES_MAX)
		return XZ_DATA_ERROR;
}

return XZ_OK;
}

/*
* Decode the Compressed Data field from a Block. Update and validate
* the observed compressed and uncompressed sizes of the Block so that
* they don't exceed the values possibly stored in the Block Header
* (validation assumes that no integer overflow occurs, since vli_type
* is normally uint64_t). Update the CRC32 or CRC64 value if presence of
* the CRC32 or CRC64 field was indicated in Stream Header.
*
* Once the decoding is finished, validate that the observed sizes match
* the sizes possibly stored in the Block Header. Update the hash and
* Block count, which are later used to validate the Index field.
*/
static enum xz_ret dec_block(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;

s->in_start = b->in_pos;
s->out_start = b->out_pos;

#ifdef XZ_DEC_BCJ
if (s->bcj_active)
	ret = xz_dec_bcj_run(s->bcj, s->lzma2, b);
else
#endif
	ret = xz_dec_lzma2_run(s->lzma2, b);

s->block.compressed += b->in_pos - s->in_start;
s->block.uncompressed += b->out_pos - s->out_start;

/*
 * There is no need to separately check for VLI_UNKNOWN, since
 * the observed sizes are always smaller than VLI_UNKNOWN.
 */
if (s->block.compressed > s->block_header.compressed
		|| s->block.uncompressed
			> s->block_header.uncompressed)
	return XZ_DATA_ERROR;

if (s->check_type == XZ_CHECK_CRC32)
	s->crc = xz_crc32(b->out + s->out_start,
			b->out_pos - s->out_start, s->crc);
#ifdef XZ_USE_CRC64
else if (s->check_type == XZ_CHECK_CRC64)
	s->crc = xz_crc64(b->out + s->out_start,
			b->out_pos - s->out_start, s->crc);
#endif

if (ret == XZ_STREAM_END) {
	if (s->block_header.compressed != VLI_UNKNOWN
			&& s->block_header.compressed
				!= s->block.compressed)
		return XZ_DATA_ERROR;

	if (s->block_header.uncompressed != VLI_UNKNOWN
			&& s->block_header.uncompressed
				!= s->block.uncompressed)
		return XZ_DATA_ERROR;

	s->block.hash.unpadded += s->block_header.size
			+ s->block.compressed;

#ifdef XZ_DEC_ANY_CHECK
	s->block.hash.unpadded += check_sizes[s->check_type];
#else
	if (s->check_type == XZ_CHECK_CRC32)
		s->block.hash.unpadded += 4;
	else if (IS_CRC64(s->check_type))
		s->block.hash.unpadded += 8;
#endif

	s->block.hash.uncompressed += s->block.uncompressed;
	s->block.hash.crc32 = xz_crc32(
			(const uint8_t *)&s->block.hash,
			sizeof(s->block.hash), s->block.hash.crc32);

	++s->block.count;
}

return ret;
}

/* Update the Index size and the CRC32 value. */
static void index_update(struct xz_dec *s, const struct xz_buf *b)
{
size_t in_used = b->in_pos - s->in_start;
s->index.size += in_used;
s->crc = xz_crc32(b->in + s->in_start, in_used, s->crc);
}

/*
* Decode the Number of Records, Unpadded Size, and Uncompressed Size
* fields from the Index field. That is, Index Padding and CRC32 are not
* decoded by this function.
*
* This can return XZ_OK (more input needed), XZ_STREAM_END (everything
* successfully decoded), or XZ_DATA_ERROR (input is corrupt).
*/
static enum xz_ret dec_index(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;

do {
	ret = dec_vli(s, b->in, &b->in_pos, b->in_size);
	if (ret != XZ_STREAM_END) {
		index_update(s, b);
		return ret;
	}

	switch (s->index.sequence) {
	case SEQ_INDEX_COUNT:
		s->index.count = s->vli;

		/*
		 * Validate that the Number of Records field
		 * indicates the same number of Records as
		 * there were Blocks in the Stream.
		 */
		if (s->index.count != s->block.count)
			return XZ_DATA_ERROR;

		s->index.sequence = SEQ_INDEX_UNPADDED;
		break;

	case SEQ_INDEX_UNPADDED:
		s->index.hash.unpadded += s->vli;
		s->index.sequence = SEQ_INDEX_UNCOMPRESSED;
		break;

	case SEQ_INDEX_UNCOMPRESSED:
		s->index.hash.uncompressed += s->vli;
		s->index.hash.crc32 = xz_crc32(
				(const uint8_t *)&s->index.hash,
				sizeof(s->index.hash),
				s->index.hash.crc32);
		--s->index.count;
		s->index.sequence = SEQ_INDEX_UNPADDED;
		break;
	}
} while (s->index.count > 0);

return XZ_STREAM_END;
}

/*
* Validate that the next four or eight input bytes match the value
* of s->crc. s->pos must be zero when starting to validate the first byte.
* The "bits" argument allows using the same code for both CRC32 and CRC64.
*/
static enum xz_ret crc_validate(struct xz_dec *s, struct xz_buf *b,
			uint32_t bits)
{
do {
	if (b->in_pos == b->in_size)
		return XZ_OK;

	if (((s->crc >> s->pos) & 0xFF) != b->in[b->in_pos++])
		return XZ_DATA_ERROR;

	s->pos += 8;

} while (s->pos < bits);

s->crc = 0;
s->pos = 0;

return XZ_STREAM_END;
}

#ifdef XZ_DEC_ANY_CHECK
/*
* Skip over the Check field when the Check ID is not supported.
* Returns true once the whole Check field has been skipped over.
*/
static bool check_skip(struct xz_dec *s, struct xz_buf *b)
{
while (s->pos < check_sizes[s->check_type]) {
	if (b->in_pos == b->in_size)
		return false;

	++b->in_pos;
	++s->pos;
}

s->pos = 0;

return true;
}
#endif

/* Decode the Stream Header field (the first 12 bytes of the .xz Stream). */
static enum xz_ret dec_stream_header(struct xz_dec *s)
{
if (!memeq(s->temp.buf, HEADER_MAGIC, HEADER_MAGIC_SIZE))
	return XZ_FORMAT_ERROR;

if (xz_crc32(s->temp.buf + HEADER_MAGIC_SIZE, 2, 0)
		!= get_le32(s->temp.buf + HEADER_MAGIC_SIZE + 2))
	return XZ_DATA_ERROR;

if (s->temp.buf[HEADER_MAGIC_SIZE] != 0)
	return XZ_OPTIONS_ERROR;

/*
 * Of integrity checks, we support none (Check ID = 0),
 * CRC32 (Check ID = 1), and optionally CRC64 (Check ID = 4).
 * However, if XZ_DEC_ANY_CHECK is defined, we will accept other
 * check types too, but then the check won't be verified and
 * a warning (XZ_UNSUPPORTED_CHECK) will be given.
 */
s->check_type = s->temp.buf[HEADER_MAGIC_SIZE + 1];

#ifdef XZ_DEC_ANY_CHECK
if (s->check_type > XZ_CHECK_MAX)
	return XZ_OPTIONS_ERROR;

if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
	return XZ_UNSUPPORTED_CHECK;
#else
if (s->check_type > XZ_CHECK_CRC32 && !IS_CRC64(s->check_type))
	return XZ_OPTIONS_ERROR;
#endif

return XZ_OK;
}

/* Decode the Stream Footer field (the last 12 bytes of the .xz Stream) */
static enum xz_ret dec_stream_footer(struct xz_dec *s)
{
if (!memeq(s->temp.buf + 10, FOOTER_MAGIC, FOOTER_MAGIC_SIZE))
	return XZ_DATA_ERROR;

if (xz_crc32(s->temp.buf + 4, 6, 0) != get_le32(s->temp.buf))
	return XZ_DATA_ERROR;

/*
 * Validate Backward Size. Note that we never added the size of the
 * Index CRC32 field to s->index.size, thus we use s->index.size / 4
 * instead of s->index.size / 4 - 1.
 */
if ((s->index.size >> 2) != get_le32(s->temp.buf + 4))
	return XZ_DATA_ERROR;

if (s->temp.buf[8] != 0 || s->temp.buf[9] != s->check_type)
	return XZ_DATA_ERROR;

/*
 * Use XZ_STREAM_END instead of XZ_OK to be more convenient
 * for the caller.
 */
return XZ_STREAM_END;
}

/* Decode the Block Header and initialize the filter chain. */
static enum xz_ret dec_block_header(struct xz_dec *s)
{
enum xz_ret ret;

/*
 * Validate the CRC32. We know that the temp buffer is at least
 * eight bytes so this is safe.
 */
s->temp.size -= 4;
if (xz_crc32(s->temp.buf, s->temp.size, 0)
		!= get_le32(s->temp.buf + s->temp.size))
	return XZ_DATA_ERROR;

s->temp.pos = 2;

/*
 * Catch unsupported Block Flags. We support only one or two filters
 * in the chain, so we catch that with the same test.
 */
#ifdef XZ_DEC_BCJ
if (s->temp.buf[1] & 0x3E)
#else
if (s->temp.buf[1] & 0x3F)
#endif
	return XZ_OPTIONS_ERROR;

/* Compressed Size */
if (s->temp.buf[1] & 0x40) {
	if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
				!= XZ_STREAM_END)
		return XZ_DATA_ERROR;

	s->block_header.compressed = s->vli;
} else {
	s->block_header.compressed = VLI_UNKNOWN;
}

/* Uncompressed Size */
if (s->temp.buf[1] & 0x80) {
	if (dec_vli(s, s->temp.buf, &s->temp.pos, s->temp.size)
			!= XZ_STREAM_END)
		return XZ_DATA_ERROR;

	s->block_header.uncompressed = s->vli;
} else {
	s->block_header.uncompressed = VLI_UNKNOWN;
}

#ifdef XZ_DEC_BCJ
/* If there are two filters, the first one must be a BCJ filter. */
s->bcj_active = s->temp.buf[1] & 0x01;
if (s->bcj_active) {
	if (s->temp.size - s->temp.pos < 2)
		return XZ_OPTIONS_ERROR;

	ret = xz_dec_bcj_reset(s->bcj, s->temp.buf[s->temp.pos++]);
	if (ret != XZ_OK)
		return ret;

	/*
	 * We don't support custom start offset,
	 * so Size of Properties must be zero.
	 */
	if (s->temp.buf[s->temp.pos++] != 0x00)
		return XZ_OPTIONS_ERROR;
}
#endif

/* Valid Filter Flags always take at least two bytes. */
if (s->temp.size - s->temp.pos < 2)
	return XZ_DATA_ERROR;

/* Filter ID = LZMA2 */
if (s->temp.buf[s->temp.pos++] != 0x21)
	return XZ_OPTIONS_ERROR;

/* Size of Properties = 1-byte Filter Properties */
if (s->temp.buf[s->temp.pos++] != 0x01)
	return XZ_OPTIONS_ERROR;

/* Filter Properties contains LZMA2 dictionary size. */
if (s->temp.size - s->temp.pos < 1)
	return XZ_DATA_ERROR;

ret = xz_dec_lzma2_reset(s->lzma2, s->temp.buf[s->temp.pos++]);
if (ret != XZ_OK)
	return ret;

/* The rest must be Header Padding. */
while (s->temp.pos < s->temp.size)
	if (s->temp.buf[s->temp.pos++] != 0x00)
		return XZ_OPTIONS_ERROR;

s->temp.pos = 0;
s->block.compressed = 0;
s->block.uncompressed = 0;

return XZ_OK;
}

static enum xz_ret dec_main(struct xz_dec *s, struct xz_buf *b)
{
enum xz_ret ret;

/*
 * Store the start position for the case when we are in the middle
 * of the Index field.
 */
s->in_start = b->in_pos;

while (true) {
	switch (s->sequence) {
	case SEQ_STREAM_HEADER:
		/*
		 * Stream Header is copied to s->temp, and then
		 * decoded from there. This way if the caller
		 * gives us only little input at a time, we can
		 * still keep the Stream Header decoding code
		 * simple. Similar approach is used in many places
		 * in this file.
		 */
		if (!fill_temp(s, b))
			return XZ_OK;

		/*
		 * If dec_stream_header() returns
		 * XZ_UNSUPPORTED_CHECK, it is still possible
		 * to continue decoding if working in multi-call
		 * mode. Thus, update s->sequence before calling
		 * dec_stream_header().
		 */
		s->sequence = SEQ_BLOCK_START;

		ret = dec_stream_header(s);
		if (ret != XZ_OK)
			return ret;

	case SEQ_BLOCK_START:
		/* We need one byte of input to continue. */
		if (b->in_pos == b->in_size)
			return XZ_OK;

		/* See if this is the beginning of the Index field. */
		if (b->in[b->in_pos] == 0) {
			s->in_start = b->in_pos++;
			s->sequence = SEQ_INDEX;
			break;
		}

		/*
		 * Calculate the size of the Block Header and
		 * prepare to decode it.
		 */
		s->block_header.size
			= ((uint32_t)b->in[b->in_pos] + 1) * 4;

		s->temp.size = s->block_header.size;
		s->temp.pos = 0;
		s->sequence = SEQ_BLOCK_HEADER;

	case SEQ_BLOCK_HEADER:
		if (!fill_temp(s, b))
			return XZ_OK;

		ret = dec_block_header(s);
		if (ret != XZ_OK)
			return ret;

		s->sequence = SEQ_BLOCK_UNCOMPRESS;

	case SEQ_BLOCK_UNCOMPRESS:
		ret = dec_block(s, b);
		if (ret != XZ_STREAM_END)
			return ret;

		s->sequence = SEQ_BLOCK_PADDING;

	case SEQ_BLOCK_PADDING:
		/*
		 * Size of Compressed Data + Block Padding
		 * must be a multiple of four. We don't need
		 * s->block.compressed for anything else
		 * anymore, so we use it here to test the size
		 * of the Block Padding field.
		 */
		while (s->block.compressed & 3) {
			if (b->in_pos == b->in_size)
				return XZ_OK;

			if (b->in[b->in_pos++] != 0)
				return XZ_DATA_ERROR;

			++s->block.compressed;
		}

		s->sequence = SEQ_BLOCK_CHECK;

	case SEQ_BLOCK_CHECK:
		if (s->check_type == XZ_CHECK_CRC32) {
			ret = crc_validate(s, b, 32);
			if (ret != XZ_STREAM_END)
				return ret;
		}
		else if (IS_CRC64(s->check_type)) {
			ret = crc_validate(s, b, 64);
			if (ret != XZ_STREAM_END)
				return ret;
		}
#ifdef XZ_DEC_ANY_CHECK
		else if (!check_skip(s, b)) {
			return XZ_OK;
		}
#endif

		s->sequence = SEQ_BLOCK_START;
		break;

	case SEQ_INDEX:
		ret = dec_index(s, b);
		if (ret != XZ_STREAM_END)
			return ret;

		s->sequence = SEQ_INDEX_PADDING;

	case SEQ_INDEX_PADDING:
		while ((s->index.size + (b->in_pos - s->in_start))
				& 3) {
			if (b->in_pos == b->in_size) {
				index_update(s, b);
				return XZ_OK;
			}

			if (b->in[b->in_pos++] != 0)
				return XZ_DATA_ERROR;
		}

		/* Finish the CRC32 value and Index size. */
		index_update(s, b);

		/* Compare the hashes to validate the Index field. */
		if (!memeq(&s->block.hash, &s->index.hash,
				sizeof(s->block.hash)))
			return XZ_DATA_ERROR;

		s->sequence = SEQ_INDEX_CRC32;

	case SEQ_INDEX_CRC32:
		ret = crc_validate(s, b, 32);
		if (ret != XZ_STREAM_END)
			return ret;

		s->temp.size = STREAM_HEADER_SIZE;
		s->sequence = SEQ_STREAM_FOOTER;

	case SEQ_STREAM_FOOTER:
		if (!fill_temp(s, b))
			return XZ_OK;

		return dec_stream_footer(s);
	}
}

/* Never reached */
}

/*
* xz_dec_run() is a wrapper for dec_main() to handle some special cases in
* multi-call and single-call decoding.
*
* In multi-call mode, we must return XZ_BUF_ERROR when it seems clear that we
* are not going to make any progress anymore. This is to prevent the caller
* from calling us infinitely when the input file is truncated or otherwise
* corrupt. Since zlib-style API allows that the caller fills the input buffer
* only when the decoder doesn't produce any new output, we have to be careful
* to avoid returning XZ_BUF_ERROR too easily: XZ_BUF_ERROR is returned only
* after the second consecutive call to xz_dec_run() that makes no progress.
*
* In single-call mode, if we couldn't decode everything and no error
* occurred, either the input is truncated or the output buffer is too small.
* Since we know that the last input byte never produces any output, we know
* that if all the input was consumed and decoding wasn't finished, the file
* must be corrupt. Otherwise the output buffer has to be too small or the
* file is corrupt in a way that decoding it produces too big output.
*
* If single-call decoding fails, we reset b->in_pos and b->out_pos back to
* their original values. This is because with some filter chains there won't
* be any valid uncompressed data in the output buffer unless the decoding
* actually succeeds (that's the price to pay of using the output buffer as
* the workspace).
*/
XZ_EXTERN enum xz_ret xz_dec_run(struct xz_dec *s, struct xz_buf *b)
{
size_t in_start;
size_t out_start;
enum xz_ret ret;

if (DEC_IS_SINGLE(s->mode))
	xz_dec_reset(s);

in_start = b->in_pos;
out_start = b->out_pos;
ret = dec_main(s, b);

if (DEC_IS_SINGLE(s->mode)) {
	if (ret == XZ_OK)
		ret = b->in_pos == b->in_size
				? XZ_DATA_ERROR : XZ_BUF_ERROR;

	if (ret != XZ_STREAM_END) {
		b->in_pos = in_start;
		b->out_pos = out_start;
	}

} else if (ret == XZ_OK && in_start == b->in_pos
		&& out_start == b->out_pos) {
	if (s->allow_buf_error)
		ret = XZ_BUF_ERROR;

	s->allow_buf_error = true;
} else {
	s->allow_buf_error = false;
}

return ret;
}

XZ_EXTERN struct xz_dec *xz_dec_init(enum xz_mode mode, uint32_t dict_max)
{
struct xz_dec *s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL)
	return NULL;

s->mode = mode;

#ifdef XZ_DEC_BCJ
s->bcj = xz_dec_bcj_create(DEC_IS_SINGLE(mode));
if (s->bcj == NULL)
	goto error_bcj;
#endif

s->lzma2 = xz_dec_lzma2_create(mode, dict_max);
if (s->lzma2 == NULL)
	goto error_lzma2;

xz_dec_reset(s);
return s;

error_lzma2:
#ifdef XZ_DEC_BCJ
xz_dec_bcj_end(s->bcj);
error_bcj:
#endif
kfree(s);
return NULL;
}

XZ_EXTERN void xz_dec_reset(struct xz_dec *s)
{
s->sequence = SEQ_STREAM_HEADER;
s->allow_buf_error = false;
s->pos = 0;
s->crc = 0;
memzero(&s->block, sizeof(s->block));
memzero(&s->index, sizeof(s->index));
s->temp.pos = 0;
s->temp.size = STREAM_HEADER_SIZE;
}

XZ_EXTERN void xz_dec_end(struct xz_dec *s)
{
if (s != NULL) {
	xz_dec_lzma2_end(s->lzma2);
#ifdef XZ_DEC_BCJ
	xz_dec_bcj_end(s->bcj);
#endif
	kfree(s);
}
}