smb: do not use tree id to match create request and response

As an SMB2 async response does not have a tree id, even if
the request has it.

Per spec, MessageId should be enough to identifiy a message request
and response uniquely across all messages that are sent on the same
SMB2 Protocol transport connection.
So, the tree id is redundant anyways.

rust/src/smb/smb.rs

@@ -670,6 +670,24 @@ impl SMBCommonHdr {
         }
 
     }
+    pub fn from2_notree(r: &Smb2Record, rec_type: u32) -> SMBCommonHdr {
+        // async responses do not have a tree id (even if the request has it)
+        // making thus the match between the two impossible.
+        // Per spec, MessageId should be enough to identifiy a message request and response uniquely
+        // across all messages that are sent on the same SMB2 Protocol transport connection.
+        // cf https://docs.microsoft.com/en-us/openspecs/windows_protocols/ms-smb2/ea4560b7-90da-4803-82b5-344754b92a79
+        let msg_id = match rec_type {
+            SMBHDR_TYPE_TRANS_FRAG | SMBHDR_TYPE_SHARE => { 0 },
+            _ => { r.message_id as u64 },
+        };
+
+        SMBCommonHdr {
+            rec_type : rec_type,
+            ssn_id : r.session_id,
+            tree_id : 0,
+            msg_id : msg_id,
+        }
+    }
     pub fn from1(r: &SmbRecord, rec_type: u32) -> SMBCommonHdr {
         let tree_id = match rec_type {
             SMBHDR_TYPE_TREE => { 0 },

rust/src/smb/smb2.rs

@@ -431,7 +431,7 @@ pub fn smb2_request_record<'b>(state: &mut SMBState, r: &Smb2Record<'b>)
                                 Some(n) => { n.to_vec() },
                                 None => {
                                     // try to find latest created file in case of chained commands
-                                    let mut guid_key = SMBCommonHdr::from2(r, SMBHDR_TYPE_FILENAME);
+                                    let mut guid_key = SMBCommonHdr::from2_notree(r, SMBHDR_TYPE_FILENAME);
                                     if guid_key.msg_id == 0 {
                                         b"<unknown>".to_vec()
                                     } else {
@@ -563,7 +563,7 @@ pub fn smb2_request_record<'b>(state: &mut SMBState, r: &Smb2Record<'b>)
 
                     SCLogDebug!("create_options {:08x}", cr.create_options);
 
-                    let name_key = SMBCommonHdr::from2(r, SMBHDR_TYPE_FILENAME);
+                    let name_key = SMBCommonHdr::from2_notree(r, SMBHDR_TYPE_FILENAME);
                     state.ssn2vec_map.insert(name_key, cr.data.to_vec());
 
                     let tx_hdr = SMBCommonHdr::from2(r, SMBHDR_TYPE_GENERICTX);
@@ -728,7 +728,7 @@ pub fn smb2_response_record<'b>(state: &mut SMBState, r: &Smb2Record<'b>)
                     Ok((_, cr)) => {
                         SCLogDebug!("SMBv2: Create response => {:?}", cr);
 
-                        let guid_key = SMBCommonHdr::from2(r, SMBHDR_TYPE_FILENAME);
+                        let guid_key = SMBCommonHdr::from2_notree(r, SMBHDR_TYPE_FILENAME);
                         if let Some(mut p) = state.ssn2vec_map.remove(&guid_key) {
                             p.retain(|&i|i != 0x00);
                             state.guid2name_map.insert(cr.guid.to_vec(), p);