Properly propagate panics

openssl/src/crypto/util.rs

@@ -1,7 +1,7 @@
 use libc::{c_int, c_char, c_void};
 
 use std::any::Any;
-use std::panic;
+use std::panic::{self, AssertUnwindSafe};
 use std::slice;
 
 /// Wraps a user-supplied callback and a slot for panics thrown inside the callback (while FFI
@@ -42,17 +42,20 @@ pub unsafe extern fn invoke_passwd_cb<F>(buf: *mut c_char,
                                          cb_state: *mut c_void)
                                          -> c_int
                                          where F: FnOnce(&mut [c_char]) -> usize {
-    let result = panic::catch_unwind(|| {
+    let callback = &mut *(cb_state as *mut CallbackState<F>);
+
+    let result = panic::catch_unwind(AssertUnwindSafe(|| {
         // build a `i8` slice to pass to the user callback
         let pass_slice = slice::from_raw_parts_mut(buf, size as usize);
-        let callback = &mut *(cb_state as *mut CallbackState<F>);
 
         callback.cb.take().unwrap()(pass_slice)
-    });
+    }));
 
-    if let Ok(len) = result {
-        return len as c_int;
-    } else {
-        return 0;
+    match result {
+        Ok(len) => len as c_int,
+        Err(err) => {
+            callback.panic = Some(err);
+            0
+        }
     }
 }