zeek/src/analyzer/protocol/zip/ZIP.cc
2020-04-07 16:08:34 -07:00

115 lines
2.1 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#include "ZIP.h"
using namespace analyzer::zip;
ZIP_Analyzer::ZIP_Analyzer(Connection* conn, bool orig, Method arg_method)
: tcp::TCP_SupportAnalyzer("ZIP", conn, orig)
{
zip = nullptr;
zip_status = Z_OK;
method = arg_method;
zip = new z_stream;
zip->zalloc = 0;
zip->zfree = 0;
zip->opaque = 0;
zip->next_out = 0;
zip->avail_out = 0;
zip->next_in = 0;
zip->avail_in = 0;
// "32" is a gross overload hack that means "check it
// for whether it's a gzip file". Sheesh.
if ( inflateInit2(zip, MAX_WBITS + 32) != Z_OK )
{
Weird("inflate_init_failed");
delete zip;
zip = nullptr;
}
}
ZIP_Analyzer::~ZIP_Analyzer()
{
delete zip;
}
void ZIP_Analyzer::Done()
{
Analyzer::Done();
if ( zip )
inflateEnd(zip);
}
void ZIP_Analyzer::DeliverStream(int len, const u_char* data, bool orig)
{
tcp::TCP_SupportAnalyzer::DeliverStream(len, data, orig);
if ( ! len || zip_status != Z_OK )
return;
static unsigned int unzip_size = 4096;
Bytef unzipbuf[unzip_size];
int allow_restart = 1;
zip->next_in = (Bytef*) data;
zip->avail_in = len;
Bytef *orig_next_in = zip->next_in;
size_t orig_avail_in = zip->avail_in;
while ( true )
{
zip->next_out = unzipbuf;
zip->avail_out = unzip_size;
zip_status = inflate(zip, Z_SYNC_FLUSH);
if ( zip_status == Z_STREAM_END ||
zip_status == Z_OK )
{
allow_restart = 0;
int have = unzip_size - zip->avail_out;
if ( have )
ForwardStream(have, unzipbuf, IsOrig());
if ( zip_status == Z_STREAM_END )
{
inflateEnd(zip);
return;
}
if ( zip->avail_in == 0 )
return;
}
else if ( allow_restart && zip_status == Z_DATA_ERROR )
{
// Some servers seem to not generate zlib headers,
// so this is an attempt to fix and continue anyway.
inflateEnd(zip);
if ( inflateInit2(zip, -MAX_WBITS) != Z_OK )
{
Weird("inflate_init_failed");
return;
}
zip->next_in = orig_next_in;
zip->avail_in = orig_avail_in;
allow_restart = 0;
continue;
}
else
{
Weird("inflate_failed");
return;
}
}
}