feat(wasm): session stores image_secret for recovery QR generation

crates/relicario-wasm/src/lib.rs

@@ -8,6 +8,7 @@ mod session;
 mod device;
 
 use wasm_bindgen::prelude::*;
+use zeroize::Zeroizing;
 
 use relicario_core::{derive_master_key, imgsecret, KdfParams};
 
@@ -36,7 +37,8 @@ pub fn unlock(
         .map_err(|_| JsError::new("salt must be exactly 32 bytes"))?;
     let master_key = derive_master_key(passphrase.as_bytes(), &image_secret, salt_arr, &params)
         .map_err(|e| JsError::new(&e.to_string()))?;
-    let handle = session::insert(master_key);
+    let stored_secret = Zeroizing::new(image_secret);
+    let handle = session::insert(master_key, stored_secret);
     Ok(SessionHandle(handle))
 }
 
@@ -492,7 +494,7 @@ mod session_tests {
     #[test]
     fn insert_then_remove_clears_entry() {
         session::clear();
-        let h = session::insert(Zeroizing::new([0x11u8; 32]));
+        let h = session::insert(Zeroizing::new([0x11u8; 32]), Zeroizing::new([0u8; 32]));
         assert_ne!(h, 0);
         assert!(session::remove(h));
         assert!(!session::remove(h));   // second remove false
@@ -501,7 +503,7 @@ mod session_tests {
     #[test]
     fn with_yields_key_only_while_session_lives() {
         session::clear();
-        let h = session::insert(Zeroizing::new([0x22u8; 32]));
+        let h = session::insert(Zeroizing::new([0x22u8; 32]), Zeroizing::new([0u8; 32]));
         let byte = session::with(h, |k| k[0]);
         assert_eq!(byte, Some(0x22));
         session::remove(h);
@@ -513,7 +515,7 @@ mod session_tests {
     fn manifest_round_trip_via_handle() {
         use relicario_core::{Manifest, decrypt_manifest};
         session::clear();
-        let h = session::insert(Zeroizing::new([0x55u8; 32]));
+        let h = session::insert(Zeroizing::new([0x55u8; 32]), Zeroizing::new([0u8; 32]));
         let handle = SessionHandle(h);
         let key = Zeroizing::new([0x55u8; 32]);
         let empty = Manifest::new();

crates/relicario-wasm/src/session.rs

@@ -6,12 +6,17 @@ use std::cell::RefCell;
 use std::collections::HashMap;
 use zeroize::Zeroizing;
 
+pub struct SessionData {
+    pub master_key: Zeroizing<[u8; 32]>,
+    pub image_secret: Zeroizing<[u8; 32]>,
+}
+
 thread_local! {
-    static SESSIONS: RefCell<HashMap<u32, Zeroizing<[u8; 32]>>> = RefCell::new(HashMap::new());
+    static SESSIONS: RefCell<HashMap<u32, SessionData>> = RefCell::new(HashMap::new());
     static NEXT_HANDLE: RefCell<u32> = const { RefCell::new(1) };
 }
 
-pub fn insert(key: Zeroizing<[u8; 32]>) -> u32 {
+pub fn insert(master_key: Zeroizing<[u8; 32]>, image_secret: Zeroizing<[u8; 32]>) -> u32 {
     let handle = NEXT_HANDLE.with(|n| {
         let mut n = n.borrow_mut();
         let h = *n;
@@ -19,15 +24,26 @@ pub fn insert(key: Zeroizing<[u8; 32]>) -> u32 {
         if *n == 0 { *n = 1; } // avoid reserving 0 as a valid handle
         h
     });
-    SESSIONS.with(|s| { s.borrow_mut().insert(handle, key); });
+    SESSIONS.with(|s| {
+        s.borrow_mut().insert(handle, SessionData { master_key, image_secret });
+    });
     handle
 }
 
+/// Access the master key for a handle. Preserves original `with` signature for all existing callers.
 pub fn with<F, R>(handle: u32, f: F) -> Option<R>
 where
     F: FnOnce(&Zeroizing<[u8; 32]>) -> R,
 {
-    SESSIONS.with(|s| s.borrow().get(&handle).map(f))
+    SESSIONS.with(|s| s.borrow().get(&handle).map(|d| f(&d.master_key)))
+}
+
+/// Access the image_secret for a handle (used by recovery QR).
+pub fn with_image_secret<F, R>(handle: u32, f: F) -> Option<R>
+where
+    F: FnOnce(&Zeroizing<[u8; 32]>) -> R,
+{
+    SESSIONS.with(|s| s.borrow().get(&handle).map(|d| f(&d.image_secret)))
 }
 
 pub fn remove(handle: u32) -> bool {