output/jsonbuilder: helper function SCJbSetPrintAsciiString

To replace C PrintStringsToBuffer and avoid a stack alloc
+ copy

Ticket: 8004

rust/src/jsonbuilder.rs

@@ -563,6 +563,52 @@ impl JsonBuilder {
         }
     }
 
+    /// Set a key with a string value taking only ascii-printable bytes.
+    /// Non-printable characters are replaced by a dot `.`, except
+    /// CR and LF which are escaped the regular json way \r and \n
+    pub fn set_print_ascii(&mut self, key: &str, val: &[u8]) -> Result<&mut Self, JsonError> {
+        match self.current_state() {
+            State::ObjectNth => {
+                self.push(',')?;
+            }
+            State::ObjectFirst => {
+                self.set_state(State::ObjectNth);
+            }
+            _ => {
+                debug_validate_fail!("invalid state");
+                return Err(JsonError::InvalidState);
+            }
+        }
+        self.push('"')?;
+        self.push_str(key)?;
+        self.push_str("\":\"")?;
+        for &x in val.iter() {
+            match x {
+                b'\r' => {
+                    self.push_str("\\r")?;
+                }
+                b'\n'=> {
+                    self.push_str("\\n")?;
+                }
+                b'"'=> {
+                    self.push_str("\\\"")?;
+                }
+                b'\\'=> {
+                    self.push_str("\\\\")?;
+                }
+                _ => {
+                    if !x.is_ascii() || x.is_ascii_control()  {
+                        self.push('.')?;
+                    } else {
+                        self.push(x as char)?;
+                    }
+                }
+            }
+        }
+        self.push('"')?;
+        Ok(self)
+    }
+
     /// Set a key and a string value (from bytes) on an object, with a limited size
     pub fn set_string_from_bytes_limited(
         &mut self, key: &str, val: &[u8], limit: usize,
@@ -933,6 +979,20 @@ pub unsafe extern "C" fn SCJbSetStringFromBytes(
     return false;
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn SCJbSetPrintAsciiString(
+    js: &mut JsonBuilder, key: *const c_char, bytes: *const u8, len: u32,
+) -> bool {
+    if bytes.is_null() || len == 0 {
+        return false;
+    }
+    if let Ok(key) = CStr::from_ptr(key).to_str() {
+        let val = std::slice::from_raw_parts(bytes, len as usize);
+        return js.set_print_ascii(key, val).is_ok();
+    }
+    return false;
+}
+
 #[no_mangle]
 pub unsafe extern "C" fn SCJbSetBase64(
     js: &mut JsonBuilder, key: *const c_char, bytes: *const u8, len: u32,

rust/sys/src/jsonbuilder.rs

@@ -51,6 +51,11 @@ extern "C" {
         js: *mut SCJsonBuilder, key: *const ::std::os::raw::c_char, bytes: *const u8, len: u32,
     ) -> bool;
 }
+extern "C" {
+    pub fn SCJbSetPrintAsciiString(
+        js: *mut SCJsonBuilder, key: *const ::std::os::raw::c_char, bytes: *const u8, len: u32,
+    ) -> bool;
+}
 extern "C" {
     pub fn SCJbSetBase64(
         js: *mut SCJsonBuilder, key: *const ::std::os::raw::c_char, bytes: *const u8, len: u32,

src/output-json-alert.c

@@ -315,13 +315,7 @@ static void AlertAddPayload(AlertJsonOutputCtx *json_output_ctx, SCJsonBuilder *
     }
 
     if (json_output_ctx->flags & LOG_JSON_PAYLOAD) {
-        uint8_t printable_buf[p->payload_len + 1];
-        uint32_t offset = 0;
-        PrintStringsToBuffer(printable_buf, &offset,
-                p->payload_len + 1,
-                p->payload, p->payload_len);
-        printable_buf[p->payload_len] = '\0';
-        SCJbSetString(js, "payload_printable", (char *)printable_buf);
+        SCJbSetPrintAsciiString(js, "payload_printable", p->payload, p->payload_len);
     }
 }
 
@@ -638,11 +632,8 @@ static bool AlertJsonStreamData(const AlertJsonOutputCtx *json_output_ctx, JsonA
         }
 
         if (json_output_ctx->flags & LOG_JSON_PAYLOAD) {
-            uint8_t printable_buf[cbd.payload->offset + 1];
-            uint32_t offset = 0;
-            PrintStringsToBuffer(printable_buf, &offset, cbd.payload->offset + 1,
-                    cbd.payload->buffer, cbd.payload->offset);
-            SCJbSetString(jb, "payload_printable", (char *)printable_buf);
+            SCJbSetPrintAsciiString(
+                    jb, "payload_printable", cbd.payload->buffer, cbd.payload->offset);
         }
         return true;
     }

src/output-json-frame.c

@@ -200,11 +200,7 @@ static void FrameAddPayloadTCP(Flow *f, const TcpSession *ssn, const TcpStream *
 
     if (cbd.payload->offset) {
         SCJbSetBase64(jb, "payload", cbd.payload->buffer, cbd.payload->offset);
-        uint8_t printable_buf[cbd.payload->offset + 1];
-        uint32_t offset = 0;
-        PrintStringsToBuffer(printable_buf, &offset, cbd.payload->offset + 1, cbd.payload->buffer,
-                cbd.payload->offset);
-        SCJbSetString(jb, "payload_printable", (char *)printable_buf);
+        SCJbSetPrintAsciiString(jb, "payload_printable", cbd.payload->buffer, cbd.payload->offset);
         SCJbSetBool(jb, "complete", complete);
     }
 }
@@ -233,11 +229,7 @@ static void FrameAddPayloadUDP(SCJsonBuilder *js, const Packet *p, const Frame *
     const uint32_t log_data_len = MIN(data_len, 256);
     SCJbSetBase64(js, "payload", data, log_data_len);
 
-    uint8_t printable_buf[log_data_len + 1];
-    uint32_t o = 0;
-    PrintStringsToBuffer(printable_buf, &o, log_data_len + 1, data, log_data_len);
-    printable_buf[log_data_len] = '\0';
-    SCJbSetString(js, "payload_printable", (char *)printable_buf);
+    SCJbSetPrintAsciiString(js, "payload_printable", data, log_data_len);
 #if 0
     char pretty_buf[data_len * 4 + 1];
     pretty_buf[0] = '\0';

src/output-json-http.c

@@ -370,7 +370,6 @@ static void EveHttpLogJSONHeaders(
 static void BodyPrintableBuffer(SCJsonBuilder *js, HtpBody *body, const char *key)
 {
     if (body->sb != NULL && body->sb->region.buf != NULL) {
-        uint32_t offset = 0;
         const uint8_t *body_data;
         uint32_t body_data_len;
         uint64_t body_offset;
@@ -380,11 +379,7 @@ static void BodyPrintableBuffer(SCJsonBuilder *js, HtpBody *body, const char *ke
             return;
         }
 
-        uint8_t printable_buf[body_data_len + 1];
-        PrintStringsToBuffer(printable_buf, &offset, body_data_len + 1, body_data, body_data_len);
-        if (offset > 0) {
-            SCJbSetString(js, key, (char *)printable_buf);
-        }
+        SCJbSetPrintAsciiString(js, key, body_data, body_data_len);
     }
 }
 

src/output-json.c

@@ -200,18 +200,10 @@ static void EveAddPacketVars(const Packet *p, SCJsonBuilder *js_vars)
                 uint32_t offset = 0;
                 uint8_t keybuf[pv->key_len + 1];
                 PrintStringsToBuffer(keybuf, &offset, pv->key_len + 1, pv->key, pv->key_len);
-                uint32_t len = pv->value_len;
-                uint8_t printable_buf[len + 1];
-                offset = 0;
-                PrintStringsToBuffer(printable_buf, &offset, len + 1, pv->value, pv->value_len);
-                SCJbSetString(js_vars, (char *)keybuf, (char *)printable_buf);
+                SCJbSetPrintAsciiString(js_vars, (char *)keybuf, pv->value, pv->value_len);
             } else {
                 const char *varname = VarNameStoreLookupById(pv->id, VAR_TYPE_PKT_VAR);
-                uint32_t len = pv->value_len;
-                uint8_t printable_buf[len + 1];
-                uint32_t offset = 0;
-                PrintStringsToBuffer(printable_buf, &offset, len + 1, pv->value, pv->value_len);
-                SCJbSetString(js_vars, varname, (char *)printable_buf);
+                SCJbSetPrintAsciiString(js_vars, varname, pv->value, pv->value_len);
             }
             SCJbClose(js_vars);
         }
@@ -263,14 +255,9 @@ static void EveAddFlowVars(const Flow *f, SCJsonBuilder *js_root, SCJsonBuilder
                             break;
                     }
 
-                    uint32_t len = fv->data.fv_str.value_len;
-                    uint8_t printable_buf[len + 1];
-                    uint32_t offset = 0;
-                    PrintStringsToBuffer(printable_buf, &offset, len + 1, fv->data.fv_str.value,
-                            fv->data.fv_str.value_len);
-
                     SCJbStartObject(js_flowvars);
-                    SCJbSetString(js_flowvars, varname, (char *)printable_buf);
+                    SCJbSetPrintAsciiString(
+                            js_flowvars, varname, fv->data.fv_str.value, fv->data.fv_str.value_len);
                     SCJbClose(js_flowvars);
                 }
             } else if (fv->datatype == FLOWVAR_TYPE_STR && fv->key != NULL) {
@@ -284,14 +271,9 @@ static void EveAddFlowVars(const Flow *f, SCJsonBuilder *js_root, SCJsonBuilder
                 uint32_t offset = 0;
                 PrintStringsToBuffer(keybuf, &offset, fv->keylen + 1, fv->key, fv->keylen);
 
-                uint32_t len = fv->data.fv_str.value_len;
-                uint8_t printable_buf[len + 1];
-                offset = 0;
-                PrintStringsToBuffer(printable_buf, &offset, len + 1, fv->data.fv_str.value,
-                        fv->data.fv_str.value_len);
-
                 SCJbStartObject(js_flowvars);
-                SCJbSetString(js_flowvars, (const char *)keybuf, (char *)printable_buf);
+                SCJbSetPrintAsciiString(js_flowvars, (const char *)keybuf, fv->data.fv_str.value,
+                        fv->data.fv_str.value_len);
                 SCJbClose(js_flowvars);
             } else if (fv->datatype == FLOWVAR_TYPE_FLOAT) {
                 const char *varname = VarNameStoreLookupById(fv->idx, VAR_TYPE_FLOW_FLOAT);