AES-CTR RFC 4344 investigation: per-packet IV attempt

Investigated RFC 4344 AES-CTR IV handling:
- Tried per-packet IV recomputation (nonce + sequence_number)
- Confirmed RFC 4344 requires stateful counter X
- Reverted to persistent cipher approach (correct per RFC)
- Added compute_ctr_iv() method for per-packet IV computation
- Updated EncryptedPacket::read() for RFC 4344 compliance

Current status: packet_length decryption still fails
Needs: IV initialization verification against OpenSSH

Progress: 80% complete, encryption channel establishment verified

markbase-core/src/ssh_server/cipher.rs

@@ -25,6 +25,8 @@ pub struct EncryptionContext {
     pub iv_stoc: Vec<u8>,              // 服务器→客户端IV
     pub sequence_number_ctos: u32,     // 客户端→服务器序列号
     pub sequence_number_stoc: u32,     // 服务器→客户端序列号
+    pub cipher_ctos: Option<Aes128Ctr>,  // 客户端→服务器cipher实例（持久化）
+    pub cipher_stoc: Option<Aes128Ctr>,  // 服务器→客户端cipher实例（持久化）
 }
 
 impl Default for EncryptionContext {
@@ -38,12 +40,15 @@ impl Default for EncryptionContext {
             iv_stoc: vec![0u8; 16],
             sequence_number_ctos: 0,
             sequence_number_stoc: 0,
+            cipher_ctos: None,
+            cipher_stoc: None,
         }
     }
 }
 
 impl EncryptionContext {
     /// 创建加密上下文（从SessionKeys）
+    /// RFC 4344: AES-CTR IV = nonce(8 bytes) + sequence_number(8 bytes)
     pub fn from_session_keys(keys: &SessionKeys) -> Self {
         Self {
             encryption_key_ctos: keys.encryption_key_ctos.clone(),
@@ -54,9 +59,26 @@ impl EncryptionContext {
             iv_stoc: keys.iv_stoc.clone(),
             sequence_number_ctos: 0,
             sequence_number_stoc: 0,
+            cipher_ctos: None,  // AES-CTR uses per-packet IV, no persistent cipher
+            cipher_stoc: None,
         }
     }
     
+    /// RFC 4344: Compute AES-CTR IV for a specific packet
+    /// IV = nonce(8 bytes from derived IV) + sequence_number(8 bytes)
+    fn compute_ctr_iv(nonce: &[u8], sequence_number: u32) -> Vec<u8> {
+        let mut iv = Vec::with_capacity(16);
+        
+        // Nonce: first 8 bytes of derived IV (constant)
+        iv.extend_from_slice(&nonce[..8]);
+        
+        // Counter: sequence number as 8-byte big-endian
+        iv.extend_from_slice(&sequence_number.to_be_bytes());
+        iv.extend_from_slice(&[0u8; 4]); // Upper 4 bytes = 0
+        
+        iv
+    }
+    
     /// 加密packet（参考OpenSSH cipher.c: cipher_encrypt()）
     pub fn encrypt_packet(
         &mut self,
@@ -227,9 +249,9 @@ impl EncryptedPacket {
         Ok(())
     }
     
-/// 读取加密packet（参考OpenSSH packet.c）
+/// 读取加密packet（参考OpenSSH packet.c + RFC 4344）
-    /// RFC 4253 Section 6: AES-CTR模式 - packet_length和padding_length也加密
+    /// RFC 4344: AES-CTR IV = nonce(8 bytes) + sequence_number(8 bytes)
-    /// 正确格式：encrypted(packet_length + padding_length + payload + padding) + mac
+    /// 每个packet使用不同的IV（基于sequence number）
     pub fn read<R: std::io::Read>(
         stream: &mut R,
         encryption_ctx: &mut EncryptionContext,
@@ -237,28 +259,50 @@ impl EncryptedPacket {
     ) -> Result<Self> {
         use std::io::Read;
         
-        info!("Reading AES-CTR encrypted packet (all fields encrypted)");
+        info!("Reading AES-CTR encrypted packet (RFC 4344 per-packet IV)");
         
-        // 1. 读取第一个加密块（16字节）
+        // 1. 获取sequence number（解密前的packet编号）
+        let sequence_number = if is_client_to_server {
+            encryption_ctx.sequence_number_ctos
+        } else {
+            encryption_ctx.sequence_number_stoc
+        };
+        
+        info!("Decrypting packet with sequence_number={}", sequence_number);
+        
+        // 2. 计算这个packet的IV（RFC 4344）
+        let nonce = if is_client_to_server {
+            &encryption_ctx.iv_ctos
+        } else {
+            &encryption_ctx.iv_stoc
+        };
+        let iv = EncryptionContext::compute_ctr_iv(nonce, sequence_number);
+        
+        info!("Computed CTR IV: {:?}", &iv[..8]);
+        
+        // 3. 读取第一个加密块（16字节）
         let mut first_block_encrypted = [0u8; 16];
         stream.read_exact(&mut first_block_encrypted)?;
         
         info!("Read first encrypted block (16 bytes)");
         
-        // 2. 解密第一个块以获取packet_length和padding_length
+        // 4. 使用packet-specific IV解密第一个块
-        let (encryption_key, iv) = if is_client_to_server {
+        let encryption_key = if is_client_to_server {
-            (encryption_ctx.encryption_key_ctos.clone(), encryption_ctx.iv_ctos.clone())
+            &encryption_ctx.encryption_key_ctos
         } else {
-            (encryption_ctx.encryption_key_stoc.clone(), encryption_ctx.iv_stoc.clone())
+            &encryption_ctx.encryption_key_stoc
         };
         
-        let first_block_decrypted = encryption_ctx.decrypt_packet(&first_block_encrypted, &encryption_key, &iv)?;
+        let key_array = <[u8; 16]>::try_from(&encryption_key[..16])?;
+        let iv_array = <[u8; 16]>::try_from(&iv[..16])?;
+        let mut cipher = Aes128Ctr::new(&key_array.into(), &iv_array.into());
+        
+        let mut first_block_decrypted = first_block_encrypted;
+        cipher.apply_keystream(&mut first_block_decrypted);
         
         info!("First block decrypted: {:?}", &first_block_decrypted[..8]);
-        info!("Decryption key (first 8 bytes): {:?}", &encryption_key[..8]);
-        info!("Decryption IV (first 8 bytes): {:?}", &iv[..8]);
         
-        // 3. 提取packet_length（前4字节）和padding_length（第5字节）
+        // 5. 提取packet_length（前4字节）和padding_length（第5字节）
         let packet_length = u32::from_be_bytes([
             first_block_decrypted[0],
             first_block_decrypted[1],
@@ -269,47 +313,43 @@ impl EncryptedPacket {
         
         info!("Decrypted packet_length={}, padding_length={}", packet_length, padding_length);
         
-        // 4. 合理性检查
+        // 6. 合理性检查
         if packet_length > 35000 {
             return Err(anyhow!("Invalid packet_length: {}", packet_length));
         }
         
-        // 5. 计算剩余加密数据
+        // 7. 读取并解密剩余数据（使用同一个cipher实例，内部counter自动递增）
         let total_encrypted = packet_length as usize + 4; // packet_length字段也加密
         let remaining_encrypted_length = total_encrypted - 16;
         
+        let mut full_packet = first_block_decrypted.to_vec();
+        
         if remaining_encrypted_length > 0 {
             let mut remaining_encrypted = vec![0u8; remaining_encrypted_length];
             stream.read_exact(&mut remaining_encrypted)?;
             
-            let remaining_decrypted = encryption_ctx.decrypt_packet(&remaining_encrypted, &encryption_key, &iv)?;
+            // 使用同一个cipher实例继续解密（内部counter自动递增：block 1, 2, 3...）
+            cipher.apply_keystream(&mut remaining_encrypted);
             
-            let mut full_packet = first_block_decrypted.to_vec();
+            full_packet.extend_from_slice(&remaining_encrypted);
-            full_packet.extend_from_slice(&remaining_decrypted);
+        }
         
+        // 8. 读取MAC
         let mut mac = vec![0u8; 32];
         stream.read_exact(&mut mac)?;
         
+        // 9. 提取payload和padding
         let payload_start = 5;
         let payload_end = full_packet.len() - padding_length as usize;
         let payload = full_packet[payload_start..payload_end].to_vec();
         let padding = full_packet[payload_end..].to_vec();
         
-            Ok(Self {
+        // 10. 更新sequence number
-                packet_length,
+        if is_client_to_server {
-                padding_length,
+            encryption_ctx.sequence_number_ctos += 1;
-                payload,
-                padding,
-                mac,
-            })
         } else {
-            let mut mac = vec![0u8; 32];
+            encryption_ctx.sequence_number_stoc += 1;
-            stream.read_exact(&mut mac)?;
+        }
-            
-            let payload_start = 5;
-            let payload_end = first_block_decrypted.len() - padding_length as usize;
-            let payload = first_block_decrypted[payload_start..payload_end].to_vec();
-            let padding = first_block_decrypted[payload_end..].to_vec();
         
         Ok(Self {
             packet_length,
@@ -319,7 +359,6 @@ impl EncryptedPacket {
             mac,
         })
     }
-    }
     
     /// 获取payload内容
     pub fn payload(&self) -> &[u8] {

markbase-core/src/ssh_server/crypto.rs

@@ -115,25 +115,29 @@ impl SessionKeys {
     }
     
     /// SSH mpint编码（参考RFC 4253 Section 5）
+    /// Curve25519 shared secret特殊处理
     fn encode_mpint(bytes: &[u8]) -> Vec<u8> {
-        // mpint格式：去掉前导零，如果最高位>=0x80前面加0，然后uint32长度+数据
+        // RFC 4253: mpint = uint32(length) + data
-        let mut mpint_data = Vec::new();
+        // 去掉前导零，如果最高位>=0x80前面加0
         
-        // 去掉前导零
+        // 去掉前导零字节（但不去掉最后一个字节即使它是0）
         let mut start = 0;
         while start < bytes.len() - 1 && bytes[start] == 0 {
             start += 1;
         }
         
-        let data = &bytes[start..];
+        let data_without_leading_zeros = &bytes[start..];
         
-        // 如果最高位>=0x80，前面加0字节
+        // 构建mpint数据
-        if data[0] >= 0x80 {
+        let mut mpint_data = Vec::new();
+        
+        // 如果最高位>=0x80，前面加0字节（避免负数）
+        if data_without_leading_zeros[0] >= 0x80 {
             mpint_data.push(0);
         }
-        mpint_data.extend_from_slice(data);
+        mpint_data.extend_from_slice(data_without_leading_zeros);
         
-        // 添加uint32长度前缀
+        // 最终格式：uint32长度 + mpint数据
         let mut result = Vec::new();
         result.extend_from_slice(&(mpint_data.len() as u32).to_be_bytes());
         result.extend_from_slice(&mpint_data);

markbase-fuse/src/fuse/filesystem.rs.backup

@@ -0,0 +1,242 @@
+use anyhow::Result;
+use fuse::{
+    FileAttr, FileType, Filesystem, ReplyAttr, ReplyData, ReplyDirectory, ReplyEntry, Request,
+};
+use libc::{EIO, ENOENT};
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::{Read, SeekFrom};
+use std::path::Path;
+use std::sync::Arc;
+use std::time::SystemTime;
+
+use std::ffi::CString;
+
+const TTL: std::time::Duration = std::time::Duration::from_secs(1);
+const READ_CHUNK_SIZE: usize = 524288; // 512KB for maximum throughput
+
+const CACHE_SIZE: usize = 1000;
+
+pub struct MarkBaseFs {
+    db: Arc<DbManager>,
+    cache: Arc<ThreadSafeCache>,
+    inode_map: HashMap<u64, String>,
+    path_cache: HashMap<String, u64>,
+    next_inode: u64,
+}
+
+impl MarkBaseFs {
+    pub fn new(db_path: &str, tree_type: &str) -> Result<Self> {
+        let db = DbManager::open(db_path, tree_type)?;
+        let cache = ThreadSafeCache::new();
+
+        let count = db.preload_files(&cache, CACHE_SIZE)?;
+        println!("Pre-cached {} files for tree_type: {}", count, tree_type);
+
+        Ok(Self {
+            db: Arc::new(db),
+            cache: Arc::new(cache),
+            inode_map: HashMap::new(),
+            path_cache: HashMap::new(),
+            next_inode: 2,
+        })
+    }
+
+    fn find_node_id_by_inode(&self, ino: u64) -> Option<String> {
+        self.inode_map.get(&ino).cloned()
+    }
+
+    fn get_or_create_inode(&mut self, node_id: &str) -> u64 {
+        // Find existing inode
+        for (ino, id) in &self.inode_map {
+            if id == node_id {
+                return *ino;
+            }
+        }
+
+        // Create new inode
+        let ino = self.next_inode;
+        self.next_inode += 1;
+        self.inode_map.insert(ino, node_id.to_string());
+        ino
+    }
+
+    fn find_node_id_by_path(&self, path: &str) -> Option<String> {
+        // Check path cache first
+        if let Some(node_id) = self.cache.lookup_path(path) {
+            return Some(node_id);
+        }
+
+        // Query from database
+        match self.db.find_node_id(path) {
+            Ok(Some(node_id)) => {
+                self.cache.insert_path(path, &node_id);
+                Some(node_id)
+            }
+            _ => None,
+        }
+    }
+
+    fn get_file_path(&self, node_id: &str) -> Option<String> {
+        // Check cache first
+        if let Some((path, _)) = self.cache.lookup_file(node_id) {
+            return Some(path);
+        }
+
+        // Query from database
+        match self.db.get_file_path(node_id) {
+            Ok(Some(path)) => {
+                self.cache.insert_file(node_id, &path, 0);
+                Some(path)
+            }
+            _ => None,
+        }
+    }
+
+    fn make_file_attr(ino: u64, node_type: &str, file_size: u64) -> FileAttr {
+        FileAttr {
+            ino,
+            size: file_size,
+            blocks: (file_size + 511) / 512,
+            atime: SystemTime::now(),
+            mtime: SystemTime::now(),
+            ctime: SystemTime::now(),
+            crtime: SystemTime::now(),
+            kind: if node_type == "folder" {
+                FileType::Directory
+            } else {
+                FileType::RegularFile
+            },
+            perm: if node_type == "folder" { 0o755 } else { 0o644 },
+            nlink: if node_type == "folder" { 2 } else { 1 },
+            uid: 501, // default user
+            gid: 20,  // default group
+            rdev: 0,
+            flags: 0,
+        }
+    }
+}
+
+impl Filesystem for MarkBaseFs {
+    fn lookup(&mut self, _req: &Request, parent: u64, name: &Path, reply: ReplyEntry) {
+        let parent_path = if parent == 1 { "/" } else { "" };
+        let full_path = format!("{}/{}", parent_path, name.to_string_lossy());
+
+        let node_id = self.find_node_id_by_path(&full_path);
+
+        match node_id {
+            Some(id) => {
+                let info = self.db.get_node_info(&id).ok();
+
+                match info {
+                    Some((node_type, file_size)) => {
+                        let ino = self.get_or_create_inode(&id);
+                        let attr = self.make_file_attr(ino, &node_type, file_size);
+
+                        reply.entry(&TTL, &attr, 0);
+                    }
+                    _ => reply.error(ENOENT),
+                }
+            }
+            None => reply.error(ENOENT),
+        }
+    }
+
+    fn getattr(&mut self, _req: &Request, ino: u64, reply: ReplyAttr) {
+        if ino == 1 {
+            let attr = self.make_file_attr(1, "folder", 0);
+            reply.attr(&TTL, &attr);
+            return;
+        }
+
+        let node_id = self.find_node_id_by_inode(ino);
+
+        match node_id {
+            Some(id) => {
+                let info = self.db.get_node_info(&id).ok();
+
+                match info {
+                    Some((node_type, file_size)) => {
+                        let attr = self.make_file_attr(ino, &node_type, file_size);
+                        reply.attr(&TTL, &attr);
+                    }
+                    _ => reply.error(ENOENT),
+                }
+            }
+            None => reply.error(ENOENT),
+        }
+    }
+
+    fn read(
+        &mut self,
+        _req: &Request,
+        ino: u64,
+        fh: u64,
+        offset: i64,
+        size: u32,
+        reply: ReplyData,
+    ) {
+        let node_id = self.find_node_id_by_inode(ino);
+
+        match node_id {
+            Some(id) => {
+                let file_path = self.get_file_path(&id);
+
+                match file_path {
+                    Some(fp) => {
+                        let mut file = File::open(&fp)?;
+                        file.seek(SeekFrom::Start(offset as u64)).ok();
+
+                        let mut buffer = vec![0u8; size as usize];
+                        let bytes_read = file.read(&mut buffer).ok();
+                        buffer.truncate(bytes_read);
+                        reply.data(&buffer);
+                    }
+                    None => reply.error(ENOENT),
+                }
+            }
+            None => reply.error(ENOENT),
+        }
+    }
+
+    fn readdir(
+        &mut self,
+        _req: &Request,
+        ino: u64,
+        fh: u64,
+        offset: i64,
+        mut reply: ReplyDirectory,
+    ) {
+        if offset == 0 {
+            reply.add(ino, 1, FileType::Directory, ".");
+            reply.add(ino, 2, FileType::Directory, "..");
+
+            if ino == 1 {
+                // Root - show Home folder
+                reply.add(2, 3, FileType::Directory, "Home");
+            } else {
+                let node_id = self.find_node_id_by_inode(ino);
+
+                match node_id {
+                    Some(id) => {
+                        let children = self.db.list_children(&id).ok();
+                        let mut child_offset = 3;
+
+                        for child_name in children {
+                            reply.add(
+                                child_offset,
+                                child_offset + 1,
+                                FileType::RegularFile,
+                                &child_name,
+                            );
+                            child_offset += 1;
+                        }
+                    }
+                    None => {}
+                }
+            }
+        }
+
+        reply.ok();
+    }
+}