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124 lines
2.5 KiB
C++
124 lines
2.5 KiB
C++
// See the file "COPYING" in the main distribution directory for copyright.
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#include <string>
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#include "Extract.h"
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#include "util.h"
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#include "Event.h"
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#include "file_analysis/Manager.h"
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using namespace file_analysis;
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Extract::Extract(RecordVal* args, File* file, const string& arg_filename,
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uint64 arg_limit)
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: file_analysis::Analyzer(file_mgr->GetComponentTag("EXTRACT"), args, file),
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filename(arg_filename), limit(arg_limit), depth(0)
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{
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fd = open(filename.c_str(), O_WRONLY | O_CREAT | O_TRUNC | O_APPEND, 0666);
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if ( fd < 0 )
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{
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fd = 0;
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char buf[128];
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strerror_r(errno, buf, sizeof(buf));
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reporter->Error("cannot open %s: %s", filename.c_str(), buf);
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}
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}
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Extract::~Extract()
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{
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if ( fd )
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safe_close(fd);
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}
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static Val* get_extract_field_val(RecordVal* args, const char* name)
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{
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Val* rval = args->Lookup(name);
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if ( ! rval )
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reporter->Error("File extraction analyzer missing arg field: %s", name);
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return rval;
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}
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file_analysis::Analyzer* Extract::Instantiate(RecordVal* args, File* file)
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{
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Val* fname = get_extract_field_val(args, "extract_filename");
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Val* limit = get_extract_field_val(args, "extract_limit");
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if ( ! fname || ! limit )
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return 0;
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return new Extract(args, file, fname->AsString()->CheckString(),
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limit->AsCount());
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}
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static bool check_limit_exceeded(uint64 lim, uint64 depth, uint64 len, uint64* n)
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{
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if ( lim == 0 )
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{
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*n = len;
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return false;
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}
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if ( depth >= lim )
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{
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*n = 0;
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return true;
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}
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else if ( depth + len > lim )
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{
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*n = lim - depth;
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return true;
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}
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else
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{
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*n = len;
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}
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return false;
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}
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bool Extract::DeliverStream(const u_char* data, uint64 len)
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{
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if ( ! fd )
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return false;
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uint64 towrite = 0;
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bool limit_exceeded = check_limit_exceeded(limit, depth, len, &towrite);
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if ( limit_exceeded && file_extraction_limit )
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{
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File* f = GetFile();
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val_list* vl = new val_list();
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vl->append(f->GetVal()->Ref());
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vl->append(Args()->Ref());
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vl->append(new Val(limit, TYPE_COUNT));
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vl->append(new Val(len, TYPE_COUNT));
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f->FileEvent(file_extraction_limit, vl);
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// Limit may have been modified by a BIF, re-check it.
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limit_exceeded = check_limit_exceeded(limit, depth, len, &towrite);
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}
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if ( towrite > 0 )
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{
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safe_write(fd, reinterpret_cast<const char*>(data), towrite);
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depth += towrite;
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}
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return ( ! limit_exceeded );
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}
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bool Extract::Undelivered(uint64 offset, uint64 len)
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{
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if ( depth == offset )
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{
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char* tmp = new char[len]();
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safe_write(fd, tmp, len);
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delete [] tmp;
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depth += len;
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}
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return true;
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}
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