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/* tvbuff_brotli.c
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include <config.h>
#include <glib.h>
#include <string.h>
#ifdef HAVE_BROTLI
#include <brotli/decode.h>
#endif
#include "tvbuff.h"
#ifdef HAVE_BROTLI
/*
* 512KiB is the buffer size used by the brotli tool, so we
* use that too.
*/
#define TVB_BROTLI_BUFSIZ (1 << 19)
static void*
brotli_g_malloc_wrapper(void *opaque _U_, size_t size)
{
return g_malloc(size);
}
static void
brotli_g_free_wrapper(void *opaque _U_, void *address)
{
g_free(address);
}
/*
* Uncompresses a brotli compressed packet inside a message of tvb at offset with
* length comprlen. Returns an uncompressed tvbuffer if uncompression
* succeeded or NULL if uncompression failed.
*/
tvbuff_t *
tvb_uncompress_brotli(tvbuff_t *tvb, const int offset, int comprlen)
{
guint8 *compr;
guint8 *uncompr = NULL;
tvbuff_t *uncompr_tvb;
BrotliDecoderState *decoder;
guint8 *strmbuf;
const size_t bufsiz = TVB_BROTLI_BUFSIZ;
size_t available_in;
const guint8 *next_in;
size_t available_out;
guint8 *next_out;
size_t total_out;
guint needs_more_output;
guint finished;
if (tvb == NULL || comprlen <= 0) {
return NULL;
}
compr = (guint8 *)tvb_memdup(NULL, tvb, offset, comprlen);
if (compr == NULL) {
return NULL;
}
decoder = BrotliDecoderCreateInstance(
&brotli_g_malloc_wrapper /*alloc_func*/,
&brotli_g_free_wrapper /*free_func*/,
NULL /*opaque*/);
if (decoder == NULL) {
wmem_free(NULL, compr);
return NULL;
}
strmbuf = (guint8 *)g_malloc(bufsiz);
available_in = comprlen;
next_in = compr;
total_out = 0;
needs_more_output = 0;
finished = 0;
while (available_in > 0 || needs_more_output) {
needs_more_output = 0;
available_out = bufsiz;
next_out = strmbuf;
BrotliDecoderResult result = BrotliDecoderDecompressStream(
decoder, &available_in, &next_in, &available_out, &next_out, &total_out);
switch (result) {
case BROTLI_DECODER_RESULT_SUCCESS:
if (available_in > 0) {
goto cleanup;
}
finished = 1;
break;
case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
needs_more_output = 1;
break;
case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
/*
* It's possible that not enough frames were captured
* to decompress this fully, so return what we've done
* so far, if any.
*/
break;
case BROTLI_DECODER_RESULT_ERROR:
default:
goto cleanup;
}
/*
* Check if decompressed size is too large.
*/
if (total_out > G_MAXINT) {
goto cleanup;
}
/*
* BrotliDecoderDecompressStream sets available_out to the number of bytes
* left unused from the buffer. But we are interested in the bytes it wrote
* to the buffer in this pass, so we calculate pass_out.
*/
size_t pass_out = bufsiz - available_out;
if (pass_out > 0) {
uncompr = (guint8 *)g_realloc(uncompr, total_out);
memcpy(uncompr + (total_out - pass_out), strmbuf, pass_out);
}
}
if (uncompr == NULL) {
/*
* This is for the case when the validly decompressed
* length is 0.
*/
if (finished) {
uncompr = (guint8 *)g_strdup("");
} else {
goto cleanup;
}
}
uncompr_tvb = tvb_new_real_data((guint8 *)uncompr, (guint)total_out, (gint)total_out);
tvb_set_free_cb(uncompr_tvb, g_free);
g_free(strmbuf);
wmem_free(NULL, compr);
BrotliDecoderDestroyInstance(decoder);
return uncompr_tvb;
cleanup:
g_free(strmbuf);
g_free(uncompr);
wmem_free(NULL, compr);
BrotliDecoderDestroyInstance(decoder);
return NULL;
}
#else
tvbuff_t *
tvb_uncompress_brotli(tvbuff_t *tvb _U_, const int offset _U_, int comprlen _U_)
{
return NULL;
}
#endif
tvbuff_t *
tvb_child_uncompress_brotli(tvbuff_t *parent, tvbuff_t *tvb, const int offset, int comprlen)
{
tvbuff_t *new_tvb = tvb_uncompress_brotli(tvb, offset, comprlen);
if (new_tvb)
tvb_set_child_real_data_tvbuff(parent, new_tvb);
return new_tvb;
}
/*
* Editor modelines - https://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 4
* tab-width: 8
* indent-tabs-mode: nil
* End:
*
* vi: set shiftwidth=4 tabstop=8 expandtab:
* :indentSize=4:tabSize=8:noTabs=true:
*/
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