1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
/* tvbuff_zstd.c
* Copyright 2022, Kevin Albertson <kevin.eric.albertson [AT] gmail.com>
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
/*
* Decompress ZSTD: http://facebook.github.io/zstd/
*/
#include "config.h"
#ifdef HAVE_ZSTD
#include <zstd.h>
#endif
#include "proto.h" // DISSECTOR_ASSERT_HINT
#include "tvbuff.h"
#include "tvbuff-int.h" // tvb_add_to_chain
#define MAX_LOOP_ITERATIONS 100
tvbuff_t *tvb_uncompress_zstd(tvbuff_t *tvb, const int offset, int comprlen)
{
#ifndef HAVE_ZSTD
// Cast to void to silence unused warnings.
(void)tvb;
(void)offset;
(void)comprlen;
return NULL;
#else
ZSTD_inBuffer input = {tvb_memdup(NULL, tvb, offset, comprlen), comprlen, 0};
ZSTD_DStream *zds = ZSTD_createDStream();
size_t rc = 0;
uint8_t *uncompr = NULL;
size_t uncompr_len = 0;
bool ok = false;
int count = 0;
// ZSTD does not consume the last byte of the frame until it has flushed all of the decompressed data of the frame.
// Therefore, loop while there is more input.
ZSTD_outBuffer output = {g_malloc(ZSTD_DStreamOutSize()), ZSTD_DStreamOutSize(), 0};
while (input.pos < input.size && count < MAX_LOOP_ITERATIONS)
{
rc = ZSTD_decompressStream(zds, &output, &input);
if (ZSTD_isError(rc))
{
goto end;
}
if (output.pos > 0)
{
if (!uncompr)
{
DISSECTOR_ASSERT (uncompr_len == 0);
uncompr = g_malloc(output.pos);
} else {
uncompr = g_realloc(uncompr, uncompr_len + output.pos);
}
memcpy (uncompr + uncompr_len, output.dst, output.pos);
uncompr_len += output.pos;
// Reset the output buffer.
output.pos = 0;
}
count++;
DISSECTOR_ASSERT_HINT(count < MAX_LOOP_ITERATIONS, "MAX_LOOP_ITERATIONS exceeded");
}
if (rc > 0)
{
// There is extra data that was not decompressed.
goto end;
}
ok = true;
end:
g_free((void *)output.dst);
wmem_free(NULL, (void *)input.src);
ZSTD_freeDStream(zds);
if (ok)
{
tvbuff_t *uncompr_tvb;
uncompr_tvb = tvb_new_real_data (uncompr, (unsigned)uncompr_len, (unsigned)uncompr_len);
tvb_set_free_cb (uncompr_tvb, g_free);
return uncompr_tvb;
}
if (uncompr)
{
g_free (uncompr);
}
return NULL;
#endif /* HAVE_ZSTD */
}
tvbuff_t *tvb_child_uncompress_zstd(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
{
tvbuff_t *uncompressed = tvb_uncompress_zstd(tvb, offset, comprlen);
if (!uncompressed)
{
return uncompressed;
}
tvb_add_to_chain(parent, uncompressed);
return uncompressed;
}
|
