feat(recovery): implement header backup/restore, BIP-39 recovery key, and integrity verification

src/verify.rs

@@ -0,0 +1,343 @@
+use std::collections::{HashMap, HashSet};
+use std::path::Path;
+
+use anyhow::{bail, Context, Result};
+use zeroize::Zeroizing;
+
+use crate::crypto::{decrypt_chunk, FORMAT_VERSION_V1, FORMAT_VERSION_V2};
+use crate::storage::Database;
+
+/// Bericht über das Ergebnis einer Container-Integritätsprüfung.
+#[derive(Debug, Clone)]
+pub struct VerificationReport {
+    pub container_path: String,
+    pub format_version: u32,
+    pub sqlite_ok: bool,
+    pub sqlite_errors: Vec<String>,
+    pub header_ok: bool,
+    pub header_error: Option<String>,
+    pub total_nodes: usize,
+    pub total_dirs: usize,
+    pub total_files: usize,
+    pub total_chunks: usize,
+    pub total_bytes_decrypted: u64,
+    pub corrupted_chunks: usize,
+    pub orphan_nodes: usize,
+    pub errors: Vec<String>,
+}
+
+impl VerificationReport {
+    pub fn is_healthy(&self) -> bool {
+        self.sqlite_ok
+            && self.header_ok
+            && self.corrupted_chunks == 0
+            && self.orphan_nodes == 0
+            && self.errors.is_empty()
+    }
+}
+
+/// Führt eine detaillierte Integritäts- und Bitrot-Prüfung auf einem Sanctum-Container durch.
+pub fn verify_container(
+    container_path: &Path,
+    dek: Option<&Zeroizing<[u8; 32]>>,
+    full_chunks: bool,
+) -> Result<VerificationReport> {
+    if !container_path.exists() {
+        bail!("Containerdatei '{}' existiert nicht.", container_path.display());
+    }
+
+    let db = Database::open(container_path)
+        .context("Konnte Container-Datenbank nicht öffnen")?;
+
+    let mut report = VerificationReport {
+        container_path: container_path.display().to_string(),
+        format_version: 0,
+        sqlite_ok: true,
+        sqlite_errors: Vec::new(),
+        header_ok: true,
+        header_error: None,
+        total_nodes: 0,
+        total_dirs: 0,
+        total_files: 0,
+        total_chunks: 0,
+        total_bytes_decrypted: 0,
+        corrupted_chunks: 0,
+        orphan_nodes: 0,
+        errors: Vec::new(),
+    };
+
+    // 1. SQLite B-Tree & Foreign Key Prüfung
+    let sqlite_issues = db.run_sqlite_integrity_check()
+        .context("Fehler bei der Ausführung des SQLite integrity_check")?;
+    if !sqlite_issues.is_empty() {
+        report.sqlite_ok = false;
+        report.sqlite_errors = sqlite_issues;
+    }
+
+    // 2. Header & Magic Bytes Prüfung
+    let meta = match db.read_meta() {
+        Ok(m) => {
+            report.format_version = m.version;
+            if m.version != FORMAT_VERSION_V1 && m.version != FORMAT_VERSION_V2 {
+                report.header_ok = false;
+                report.header_error = Some(format!("Unbekannte Formatversion: {}", m.version));
+            }
+            if m.kdf_salt.len() != 16 {
+                report.header_ok = false;
+                report.header_error = Some("Ungültige KDF-Salt-Länge".to_string());
+            }
+            Some(m)
+        }
+        Err(e) => {
+            report.header_ok = false;
+            report.header_error = Some(format!("{e}"));
+            None
+        }
+    };
+
+    // 3. Node-Hierarchie & Strukturprüfung
+    let (dirs, files, chunks_count) = db.count_nodes_and_chunks()
+        .context("Fehler beim Zählen der Knoten und Chunks")?;
+    report.total_dirs = dirs;
+    report.total_files = files;
+    report.total_chunks = chunks_count;
+
+    let all_nodes = db.list_all_nodes().context("Fehler beim Laden der Knotenliste")?;
+    report.total_nodes = all_nodes.len();
+
+    let mut node_map = HashMap::new();
+    for node in &all_nodes {
+        node_map.insert(node.id, node.clone());
+    }
+
+    // Root-Knoten prüfen (id = 1)
+    match node_map.get(&1) {
+        Some(root) => {
+            if !root.is_dir {
+                report.errors.push("Root-Knoten (id=1) ist nicht als Verzeichnis markiert!".to_string());
+            }
+            if root.parent_id.is_some() {
+                report.errors.push("Root-Knoten (id=1) darf keinen Parent haben!".to_string());
+            }
+        }
+        None => {
+            report.errors.push("Root-Knoten (id=1) fehlt in der nodes-Tabelle!".to_string());
+        }
+    }
+
+    // Alle anderen Knoten prüfen: Existenz des Parents, keine Zyklen
+    for node in &all_nodes {
+        if node.id == 1 {
+            continue;
+        }
+
+        match node.parent_id {
+            Some(pid) => match node_map.get(&pid) {
+                Some(parent) => {
+                    if !parent.is_dir {
+                        report.errors.push(format!(
+                            "Knoten '{}' (id={}) hat einen Parent (id={}), der kein Verzeichnis ist!",
+                            node.name, node.id, pid
+                        ));
+                    }
+                }
+                None => {
+                    report.orphan_nodes += 1;
+                    report.errors.push(format!(
+                        "Verwaister Knoten: '{}' (id={}) verweist auf nicht-existenten Parent id={}",
+                        node.name, node.id, pid
+                    ));
+                }
+            },
+            None => {
+                report.orphan_nodes += 1;
+                report.errors.push(format!(
+                    "Verwaister Knoten ohne Parent: '{}' (id={})",
+                    node.name, node.id
+                ));
+            }
+        }
+
+        // Zyklenprüfung
+        let mut visited = HashSet::new();
+        visited.insert(node.id);
+        let mut curr_parent = node.parent_id;
+        while let Some(pid) = curr_parent {
+            if !visited.insert(pid) {
+                report.errors.push(format!(
+                    "Zyklische Verzeichnisreferenz bei Knoten '{}' (id={}) entdeckt!",
+                    node.name, node.id
+                ));
+                break;
+            }
+            curr_parent = node_map.get(&pid).and_then(|n| n.parent_id);
+        }
+    }
+
+    // 4. Kryptografische Chunk- & AEAD-Authentifizierungsprüfung
+    let chunk_headers = db.list_all_chunk_headers()
+        .context("Fehler beim Abrufen der Chunk-Liste")?;
+
+    let format_version = meta.as_ref().map(|m| m.version).unwrap_or(FORMAT_VERSION_V2);
+
+    for (node_id, chunk_index) in chunk_headers {
+        if !node_map.contains_key(&node_id) {
+            report.errors.push(format!(
+                "Verwaister Daten-Chunk: Node #{node_id} Chunk #{chunk_index} gehört zu keinem bekannten Inode!"
+            ));
+        }
+
+        if let Some(active_dek) = dek {
+            if full_chunks {
+                match db.read_chunk(node_id, chunk_index) {
+                    Ok(Some(record)) => {
+                        match decrypt_chunk(
+                            active_dek,
+                            node_id,
+                            chunk_index,
+                            &record.ciphertext,
+                            &record.nonce,
+                            &record.tag,
+                            format_version,
+                        ) {
+                            Ok(plaintext) => {
+                                report.total_bytes_decrypted += plaintext.len() as u64;
+                            }
+                            Err(e) => {
+                                report.corrupted_chunks += 1;
+                                report.errors.push(format!(
+                                    "AEAD/Integritätsfehler bei Node #{node_id} Chunk #{chunk_index}: {e}"
+                                ));
+                            }
+                        }
+                    }
+                    Ok(None) => {
+                        report.errors.push(format!(
+                            "Chunk #{chunk_index} für Node #{node_id} in Index gefunden, aber Daten nicht lesbar!"
+                        ));
+                    }
+                    Err(e) => {
+                        report.corrupted_chunks += 1;
+                        report.errors.push(format!(
+                            "DB-Lesefehler bei Node #{node_id} Chunk #{chunk_index}: {e}"
+                        ));
+                    }
+                }
+            }
+        }
+    }
+
+    Ok(report)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::crypto::{
+        derive_kek, encrypt_chunk, generate_dek, generate_salt, wrap_dek, KdfParams, FORMAT_VERSION,
+    };
+    use std::fs;
+    use std::path::PathBuf;
+
+    #[test]
+    fn test_verify_healthy_container() {
+        let temp_dir = std::env::temp_dir();
+        let container_path: PathBuf =
+            temp_dir.join(format!("test_verify_ok_{}.sanctum", std::process::id()));
+
+        if container_path.exists() {
+            let _ = fs::remove_file(&container_path);
+        }
+
+        let password = "HealthyTestPassword123!";
+        let salt = generate_salt();
+        let kdf_params = KdfParams {
+            memory_cost: 1024,
+            time_cost: 1,
+            parallelism: 1,
+        };
+        let kek = derive_kek(password, &salt, &kdf_params).unwrap();
+        let dek = generate_dek();
+        let (wrapped_dek, nonce, tag) = wrap_dek(&kek, &dek).unwrap();
+
+        let db = Database::open(&container_path).unwrap();
+        db.init_schema(&salt, &kdf_params, &wrapped_dek, &nonce, &tag).unwrap();
+
+        // Verzeichnis & Datei anlegen
+        let folder = db.create_node(1, "photos", true).unwrap();
+        let file = db.create_node(folder.id, "img.jpg", false).unwrap();
+
+        // 2 Chunks schreiben
+        let chunk0_data = b"Sample JPEG data header and pixels";
+        let (ct0, n0, t0) = encrypt_chunk(&dek, file.id, 0, chunk0_data, FORMAT_VERSION).unwrap();
+        db.write_chunk(file.id, 0, &n0, &t0, &ct0).unwrap();
+
+        let chunk1_data = b"Additional payload data bytes";
+        let (ct1, n1, t1) = encrypt_chunk(&dek, file.id, 1, chunk1_data, FORMAT_VERSION).unwrap();
+        db.write_chunk(file.id, 1, &n1, &t1, &ct1).unwrap();
+
+        db.update_node_size_and_time(file.id, (chunk0_data.len() + chunk1_data.len()) as u64, 1000).unwrap();
+        db.checkpoint().unwrap();
+
+        // Verifizieren
+        let report = verify_container(&container_path, Some(&dek), true).expect("Verify container");
+        assert!(report.is_healthy(), "Container must be healthy, report: {:?}", report);
+        assert_eq!(report.total_files, 1);
+        assert_eq!(report.total_dirs, 2); // Root + photos
+        assert_eq!(report.total_chunks, 2);
+        assert_eq!(report.corrupted_chunks, 0);
+        assert_eq!(report.orphan_nodes, 0);
+
+        let _ = fs::remove_file(&container_path);
+    }
+
+    #[test]
+    fn test_verify_detects_bitrot() {
+        let temp_dir = std::env::temp_dir();
+        let container_path: PathBuf =
+            temp_dir.join(format!("test_verify_bitrot_{}.sanctum", std::process::id()));
+
+        if container_path.exists() {
+            let _ = fs::remove_file(&container_path);
+        }
+
+        let password = "BitrotTestPassword123!";
+        let salt = generate_salt();
+        let kdf_params = KdfParams {
+            memory_cost: 1024,
+            time_cost: 1,
+            parallelism: 1,
+        };
+        let kek = derive_kek(password, &salt, &kdf_params).unwrap();
+        let dek = generate_dek();
+        let (wrapped_dek, nonce, tag) = wrap_dek(&kek, &dek).unwrap();
+
+        let db = Database::open(&container_path).unwrap();
+        db.init_schema(&salt, &kdf_params, &wrapped_dek, &nonce, &tag).unwrap();
+
+        let file = db.create_node(1, "document.pdf", false).unwrap();
+        let chunk_data = b"Vital documents that must not be corrupted";
+        let (ct, n, t) = encrypt_chunk(&dek, file.id, 0, chunk_data, FORMAT_VERSION).unwrap();
+        db.write_chunk(file.id, 0, &n, &t, &ct).unwrap();
+        db.checkpoint().unwrap();
+        drop(db);
+
+        // Bitrot simulieren: Wir flippen 1 Byte im Ciphertext in SQLite direkt
+        let conn = rusqlite::Connection::open(&container_path).unwrap();
+        let mut corrupted_ct = ct.clone();
+        corrupted_ct[4] ^= 0xFF; // Bit-Flip!
+        conn.execute(
+            "UPDATE chunks SET ciphertext = ?1 WHERE node_id = ?2 AND chunk_index = 0",
+            rusqlite::params![corrupted_ct, file.id],
+        ).unwrap();
+        drop(conn);
+
+        // Verifizieren: Muss Bitrot via AEAD Tag-Fehler sofort entlarven!
+        let report = verify_container(&container_path, Some(&dek), true).expect("Verify container");
+        assert!(!report.is_healthy(), "Container must report unhealthy due to bitrot");
+        assert_eq!(report.corrupted_chunks, 1, "Must detect exactly 1 corrupted chunk");
+        assert!(report.errors.iter().any(|e| e.contains("AEAD/Integritätsfehler")));
+
+        let _ = fs::remove_file(&container_path);
+    }
+}