transforms: move compress_whitespace to rust

Ticket: 7229

Author: catenacyber

rust/src/detect/transforms/compress_whitespace.rs

@@ -0,0 +1,160 @@
+/* Copyright (C) 2024 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+use super::{
+    DetectHelperTransformRegister, DetectSignatureAddTransform, InspectionBufferCheckAndExpand,
+    InspectionBufferLength, InspectionBufferPtr, InspectionBufferTruncate, SCTransformTableElmt,
+};
+use crate::detect::SIGMATCH_NOOPT;
+
+use std::os::raw::{c_int, c_void};
+use std::ptr;
+
+static mut G_TRANSFORM_COMPRESS_WHITESPACE_ID: c_int = 0;
+
+#[no_mangle]
+unsafe extern "C" fn compress_whitespace_setup(
+    _de: *mut c_void, s: *mut c_void, _raw: *const std::os::raw::c_char,
+) -> c_int {
+    return DetectSignatureAddTransform(s, G_TRANSFORM_COMPRESS_WHITESPACE_ID, ptr::null_mut());
+}
+
+fn compress_whitespace_transform_do(input: &[u8], output: &mut [u8]) -> u32 {
+    let mut nb = 0;
+    // seems faster than writing one byte at a time via
+    // for (i, o) in input.iter().filter(|c| !matches!(*c, b'\t' | b'\n' | b'\x0B' | b'\x0C' | b'\r' | b' ')).zip(output)
+    for subslice in
+        input.split_inclusive(|c| matches!(*c, b'\t' | b'\n' | b'\x0B' | b'\x0C' | b'\r' | b' '))
+    {
+        // a subslice of length 1 not at the beginning is a space following another space
+        if nb == 0
+            || subslice.len() > 1
+            || !matches!(
+                subslice[0],
+                b'\t' | b'\n' | b'\x0B' | b'\x0C' | b'\r' | b' '
+            )
+        {
+            output[nb..nb + subslice.len()].copy_from_slice(subslice);
+            nb += subslice.len();
+        }
+    }
+    return nb as u32;
+}
+
+#[no_mangle]
+unsafe extern "C" fn compress_whitespace_transform(buffer: *mut c_void, _ctx: *mut c_void) {
+    let input = InspectionBufferPtr(buffer);
+    let input_len = InspectionBufferLength(buffer);
+    if input.is_null() || input_len == 0 {
+        return;
+    }
+    let input = build_slice!(input, input_len as usize);
+
+    let output = InspectionBufferCheckAndExpand(buffer, input_len);
+    if output.is_null() {
+        // allocation failure
+        return;
+    }
+    let output = std::slice::from_raw_parts_mut(output, input_len as usize);
+
+    let output_len = compress_whitespace_transform_do(input, output);
+
+    InspectionBufferTruncate(buffer, output_len);
+}
+
+fn compress_whitespace_validate_do(input: &[u8]) -> bool {
+    let mut space = false;
+    for &c in input {
+        if space {
+            if matches!(c, b'\t' | b'\n' | b'\x0B' | b'\x0C' | b'\r' | b' ') {
+                return false;
+            }
+            space = false;
+        } else if matches!(c, b'\t' | b'\n' | b'\x0B' | b'\x0C' | b'\r' | b' ') {
+            space = true;
+        }
+    }
+    return true;
+}
+
+#[no_mangle]
+unsafe extern "C" fn compress_whitespace_validate(
+    content: *const u8, len: u16, _ctx: *mut c_void,
+) -> bool {
+    let input = build_slice!(content, len as usize);
+    return compress_whitespace_validate_do(input);
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn DetectTransformCompressWhitespaceRegister() {
+    let kw = SCTransformTableElmt {
+        name: b"compress_whitespace\0".as_ptr() as *const libc::c_char,
+        desc: b"modify buffer to compress consecutive whitespace characters into a single one before inspection\0".as_ptr()
+            as *const libc::c_char,
+        url: b"/rules/transforms.html#compress-whitespace\0".as_ptr() as *const libc::c_char,
+        Setup: compress_whitespace_setup,
+        flags: SIGMATCH_NOOPT,
+        Transform: compress_whitespace_transform,
+        Free: None,
+        TransformValidate: Some(compress_whitespace_validate),
+    };
+    unsafe {
+        G_TRANSFORM_COMPRESS_WHITESPACE_ID = DetectHelperTransformRegister(&kw);
+        if G_TRANSFORM_COMPRESS_WHITESPACE_ID < 0 {
+            SCLogWarning!("Failed registering transform compress_whitespace");
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_compress_whitespace_transform() {
+        let buf = b" A B C D ";
+        let mut out = vec![0; buf.len()];
+        let exp = b" A B C D ";
+        assert_eq!(
+            compress_whitespace_transform_do(buf, &mut out),
+            exp.len() as u32
+        );
+        assert_eq!(&out[..exp.len()], exp);
+        let buf = b"EFGH";
+        let mut out = vec![0; buf.len()];
+        let exp = b"EFGH";
+        assert_eq!(
+            compress_whitespace_transform_do(buf, &mut out),
+            exp.len() as u32
+        );
+        assert_eq!(&out[..exp.len()], exp);
+        let buf = b"I  \t J";
+        let mut out = vec![0; buf.len()];
+        let exp = b"I J";
+        assert_eq!(
+            compress_whitespace_transform_do(buf, &mut out),
+            exp.len() as u32
+        );
+        assert_eq!(&out[..exp.len()], exp);
+    }
+
+    #[test]
+    fn test_compress_whitespace_validate() {
+        assert!(compress_whitespace_validate_do(b" A B C D "));
+        assert!(!compress_whitespace_validate_do(b" A B C D  "));
+    }
+}

rust/src/detect/transforms/mod.rs

@@ -19,6 +19,7 @@
 
 use std::os::raw::{c_char, c_int, c_void};
 
+pub mod compress_whitespace;
 pub mod strip_whitespace;
 
 #[repr(C)]

src/Makefile.am

@@ -308,7 +308,6 @@ noinst_HEADERS = \
 	detect-tos.h \
 	detect-transform-base64.h \
 	detect-transform-casechange.h \
-	detect-transform-compress-whitespace.h \
 	detect-transform-dotprefix.h \
 	detect-transform-header-lowercase.h \
 	detect-transform-md5.h \
@@ -880,7 +879,6 @@ libsuricata_c_a_SOURCES = \
 	detect-tos.c \
 	detect-transform-base64.c \
 	detect-transform-casechange.c \
-	detect-transform-compress-whitespace.c \
 	detect-transform-dotprefix.c \
 	detect-transform-header-lowercase.c \
 	detect-transform-md5.c \

src/detect-engine-register.c

@@ -216,7 +216,6 @@
 #include "detect-ftpdata.h"
 #include "detect-engine-content-inspection.h"
 
-#include "detect-transform-compress-whitespace.h"
 #include "detect-transform-strip-pseudo-headers.h"
 #include "detect-transform-md5.h"
 #include "detect-transform-sha1.h"