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More file reassembly work.

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- The reassembly behavior can be modified per-file by enabling or
   disabling the reassembler and/or modifying the size of the reassembly
   buffer.

 - Changed the file extraction analyzer to use the stream to avoid
   issues with the chunk based approach not immediately triggering
   the file_new event due to mime-type detection delay.  Early chunks
   frequently ended up lost before.

 - Generally things are working now and I'd consider this in testing.
This commit is contained in:
Seth Hall 2014-01-05 04:58:01 -05:00
parent 0b78f444a1
commit 38dbba7622
23 changed files with 375 additions and 159 deletions
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39
src/file_analysis/File.h
View file

@ -169,6 +169,7 @@ public:
protected:
friend class Manager;
friend class FileReassembler;
/**
* Constructor; only file_analysis::Manager should be creating these.
@ -236,6 +237,33 @@ protected:
*/
bool DetectMIME(const u_char* data, uint64 len);
/**
* Enables reassembly on the file.
*/
void EnableReassembly();
/**
* Disables reassembly on the file. If there is an existing reassembler
* for the file, this will cause it to be deleted and won't allow a new
* one to be created until reassembly is reenabled.
*/
void DisableReassembly();
/**
* Set a maximum allowed bytes of memory for file reassembly for this file.
*/
void SetReassemblyBuffer(uint64 max);
/**
* Perform stream-wise delivery for analyzers that need it.
*/
void DeliverStream(const u_char* data, uint64 len);
/**
* Perform chunk-wise delivery for analyzers that need it.
*/
void DeliverChunk(const u_char* data, uint64 len, uint64 offset);
/**
* Lookup a record field index/offset by name.
* @param field_name the name of the \c fa_file record field.
@ -248,18 +276,17 @@ protected:
*/
static void StaticInit();
private:
protected:
string id; /**< A pretty hash that likely identifies file */
RecordVal* val; /**< \c fa_file from script layer. */
uint64 forwarded_offset; /**< The offset of the file which has been forwarded. */
FileReassembler *file_reassembler; /**< A reassembler for the file if it's needed. */
uint64 stream_offset; /**< The offset of the file which has been forwarded. */
uint64 reassembly_max_buffer; /**< Maximum allowed buffer for reassembly. */
bool reassembly_enabled; /**< Whether file stream reassembly is needed. */
bool postpone_timeout; /**< Whether postponing timeout is requested. */
bool first_chunk; /**< Track first non-linear chunk. */
bool missed_bof; /**< Flags that we missed start of file. */
bool need_reassembly; /**< Whether file stream reassembly is needed. */
bool done; /**< If this object is about to be deleted. */
bool did_file_new_event; /**< Whether the file_new event has been done. */
AnalyzerSet analyzers; /**< A set of attached file analyzer. */
AnalyzerSet analyzers; /**< A set of attached file analyzers. */
queue<pair<EventHandlerPtr, val_list*> > fonc_queue;
struct BOF_Buffer {