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file/swf: Use lzma-rs decompression instead of libhtp. #7625

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file/swf: Use lzma-rs decompression instead of libhtp. #7625

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1 change: 1 addition & 0 deletions rust/Cargo.toml.in
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,7 @@ bitflags = "~1.2.1"
byteorder = "~1.4.2"
uuid = "~0.8.2"
crc = "~1.8.1"
lzma-rs = { version = "~0.2.0", features = ["stream"] }
memchr = "~2.4.1"
num = "~0.2.1"
num-derive = "~0.2.5"
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1 change: 1 addition & 0 deletions rust/src/lib.rs
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Expand Up @@ -134,5 +134,6 @@ pub mod ssh;
pub mod http2;
pub mod quic;
pub mod plugin;
pub mod lzma;
pub mod util;
pub mod ffi;
63 changes: 63 additions & 0 deletions rust/src/lzma.rs
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@@ -0,0 +1,63 @@
use lzma_rs::decompress::{Options, Stream};
use lzma_rs::error::Error;
use std::io::{Cursor, Write};

/// Propagate lzma crate errors
#[repr(C)]
pub enum LzmaStatus {
LzmaOk,
LzmaIoError,
LzmaHeaderTooShortError,
LzmaError,
LzmaXzError,
}

impl From<Error> for LzmaStatus {
fn from(e: Error) -> LzmaStatus {
match e {
Error::IoError(_) => LzmaStatus::LzmaIoError,
Error::HeaderTooShort(_) => LzmaStatus::LzmaHeaderTooShortError,
Error::LzmaError(_) => LzmaStatus::LzmaError,
Error::XzError(_) => LzmaStatus::LzmaXzError,
}
}
}

impl From<std::io::Error> for LzmaStatus {
fn from(_e: std::io::Error) -> LzmaStatus {
LzmaStatus::LzmaIoError
}
}

/// Use the lzma algorithm to decompress a chunk of data.
#[no_mangle]
pub unsafe extern "C" fn lzma_decompress(
input: *const u8, input_len: &mut usize, output: *mut u8, output_len: &mut usize,
allow_incomplete: bool, memlimit: usize,
) -> LzmaStatus {
let input = std::slice::from_raw_parts(input, *input_len);
let output = std::slice::from_raw_parts_mut(output, *output_len);
let output = Cursor::new(output);

let options = Options {
memlimit: Some(memlimit),
allow_incomplete,
..Default::default()
};

let mut stream = Stream::new_with_options(&options, output);

if let Err(e) = stream.write_all(input) {
if !allow_incomplete {
return e.into();
}
}

match stream.finish() {
Ok(output) => {
*output_len = output.position() as usize;
LzmaStatus::LzmaOk
}
Err(e) => e.into(),
}
}
8 changes: 3 additions & 5 deletions src/detect-engine.c
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Expand Up @@ -114,12 +114,10 @@ SCEnumCharMap det_ctx_event_table[] = {
{ "Z_STREAM_ERROR", FILE_DECODER_EVENT_Z_STREAM_ERROR },
{ "Z_BUF_ERROR", FILE_DECODER_EVENT_Z_BUF_ERROR },
{ "Z_UNKNOWN_ERROR", FILE_DECODER_EVENT_Z_UNKNOWN_ERROR },
{ "LZMA_IO_ERROR", FILE_DECODER_EVENT_LZMA_IO_ERROR },
{ "LZMA_HEADER_TOO_SHORT_ERROR", FILE_DECODER_EVENT_LZMA_HEADER_TOO_SHORT_ERROR },
{ "LZMA_DECODER_ERROR", FILE_DECODER_EVENT_LZMA_DECODER_ERROR },
{ "LZMA_MEMLIMIT_ERROR", FILE_DECODER_EVENT_LZMA_MEMLIMIT_ERROR },
{ "LZMA_OPTIONS_ERROR", FILE_DECODER_EVENT_LZMA_OPTIONS_ERROR },
{ "LZMA_FORMAT_ERROR", FILE_DECODER_EVENT_LZMA_FORMAT_ERROR },
{ "LZMA_DATA_ERROR", FILE_DECODER_EVENT_LZMA_DATA_ERROR },
{ "LZMA_BUF_ERROR", FILE_DECODER_EVENT_LZMA_BUF_ERROR },
{ "LZMA_XZ_ERROR", FILE_DECODER_EVENT_LZMA_XZ_ERROR },
{ "LZMA_UNKNOWN_ERROR", FILE_DECODER_EVENT_LZMA_UNKNOWN_ERROR },
{
"TOO_MANY_BUFFERS",
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8 changes: 3 additions & 5 deletions src/detect.h
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Expand Up @@ -1266,12 +1266,10 @@ enum {
FILE_DECODER_EVENT_Z_STREAM_ERROR,
FILE_DECODER_EVENT_Z_BUF_ERROR,
FILE_DECODER_EVENT_Z_UNKNOWN_ERROR,
FILE_DECODER_EVENT_LZMA_IO_ERROR,
FILE_DECODER_EVENT_LZMA_HEADER_TOO_SHORT_ERROR,
FILE_DECODER_EVENT_LZMA_DECODER_ERROR,
FILE_DECODER_EVENT_LZMA_MEMLIMIT_ERROR,
FILE_DECODER_EVENT_LZMA_OPTIONS_ERROR,
FILE_DECODER_EVENT_LZMA_FORMAT_ERROR,
FILE_DECODER_EVENT_LZMA_DATA_ERROR,
FILE_DECODER_EVENT_LZMA_BUF_ERROR,
FILE_DECODER_EVENT_LZMA_XZ_ERROR,
FILE_DECODER_EVENT_LZMA_UNKNOWN_ERROR,

DETECT_EVENT_TOO_MANY_BUFFERS,
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47 changes: 13 additions & 34 deletions src/util-file-swf-decompression.c
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Expand Up @@ -32,9 +32,9 @@
#include "util-misc.h"
#include "util-print.h"

#include <zlib.h>
#include "rust.h"

#include <htp/lzma/LzmaDec.h>
#include <zlib.h>
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Can the zlib.h include be removed?

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I don't think so. It is still used in the CWS decompression path.

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Ok, make sense. Even if removed from this file, its pulled in via one of the other includes, so we shouldn't remove it.


#define MAX_SWF_DECOMPRESSED_LEN 50000000
/*
Expand Down Expand Up @@ -129,10 +129,6 @@ int FileSwfZlibDecompression(DetectEngineThreadCtx *det_ctx,
return ret;
}

static void *SzAlloc(ISzAllocPtr p, size_t size) { return malloc(size); }
static void SzFree(ISzAllocPtr p, void *address) { free(address); }
static const ISzAlloc suri_lzma_Alloc = { SzAlloc, SzFree };

/* ZWS format */
/*
* | 4 bytes | 4 bytes | 4 bytes | 5 bytes | n bytes | 6 bytes |
Expand All @@ -144,46 +140,30 @@ int FileSwfLzmaDecompression(DetectEngineThreadCtx *det_ctx,
{
int ret = 0;

CLzmaDec strm;
LzmaDec_Construct(&strm);
ELzmaStatus status;

if (compressed_data_len < LZMA_PROPS_SIZE + 8) {
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_FORMAT_ERROR);
return 0;
}
ret = LzmaDec_Allocate(&strm, compressed_data, LZMA_PROPS_SIZE, &suri_lzma_Alloc);
if (ret != SZ_OK) {
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_DECODER_ERROR);
return 0;
}
LzmaDec_Init(&strm);
compressed_data += LZMA_PROPS_SIZE + 8;
compressed_data_len -= LZMA_PROPS_SIZE + 8;
size_t inprocessed = compressed_data_len;
size_t outprocessed = decompressed_data_len;

ret = LzmaDec_DecodeToBuf(&strm, decompressed_data, &outprocessed,
compressed_data, &inprocessed, LZMA_FINISH_ANY, &status, MAX_SWF_DECOMPRESSED_LEN);
ret = lzma_decompress(compressed_data, &inprocessed, decompressed_data,
&outprocessed, true, MAX_SWF_DECOMPRESSED_LEN);

switch(ret) {
case SZ_OK:
case LzmaOk:
ret = 1;
break;
case SZ_ERROR_MEM:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_MEMLIMIT_ERROR);
case LzmaIoError:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_IO_ERROR);
ret = 0;
break;
case SZ_ERROR_UNSUPPORTED:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_OPTIONS_ERROR);
case LzmaHeaderTooShortError:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_HEADER_TOO_SHORT_ERROR);
ret = 0;
break;
case SZ_ERROR_DATA:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_DATA_ERROR);
case LzmaError:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_DECODER_ERROR);
ret = 0;
break;
case SZ_ERROR_INPUT_EOF:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_BUF_ERROR);
case LzmaXzError:
DetectEngineSetEvent(det_ctx, FILE_DECODER_EVENT_LZMA_XZ_ERROR);
ret = 0;
break;
default:
Expand All @@ -192,6 +172,5 @@ int FileSwfLzmaDecompression(DetectEngineThreadCtx *det_ctx,
break;
}

LzmaDec_Free(&strm, &suri_lzma_Alloc);
return ret;
}