diff --git a/openssl/src/ssl/callbacks.rs b/openssl/src/ssl/callbacks.rs
index 424bdc1a..60d40fc7 100644
--- a/openssl/src/ssl/callbacks.rs
+++ b/openssl/src/ssl/callbacks.rs
@@ -365,10 +365,10 @@ where
 pub extern "C" fn raw_cookie_generate<F>(
     ssl: *mut ffi::SSL,
     cookie: *mut c_uchar,
-    cookie_len: *mut c_uint
+    cookie_len: *mut c_uint,
 ) -> c_int
 where
-    F: Fn(&mut SslRef, &mut [u8]) -> Result<usize, ErrorStack> + 'static + Sync + Send
+    F: Fn(&mut SslRef, &mut [u8]) -> Result<usize, ErrorStack> + 'static + Sync + Send,
 {
     unsafe {
         let ssl_ctx = ffi::SSL_get_SSL_CTX(ssl as *const _);
@@ -377,13 +377,17 @@ where
         let callback = &*(callback as *mut F);
         // We subtract 1 from DTLS1_COOKIE_LENGTH as the ostensible value, 256, is erroneous but retained for
         // compatibility. See comments in dtls1.h.
-        let slice = slice::from_raw_parts_mut(cookie as *mut u8, ffi::DTLS1_COOKIE_LENGTH as usize - 1);
+        let slice =
+            slice::from_raw_parts_mut(cookie as *mut u8, ffi::DTLS1_COOKIE_LENGTH as usize - 1);
         match callback(ssl, slice) {
             Ok(len) => {
                 *cookie_len = len as c_uint;
                 1
             }
-            Err(_) => 0,
+            Err(e) => {
+                e.put();
+                0
+            }
         }
     }
 }
@@ -397,17 +401,18 @@ type CookiePtr = *mut c_uchar;
 pub extern "C" fn raw_cookie_verify<F>(
     ssl: *mut ffi::SSL,
     cookie: CookiePtr,
-    cookie_len: c_uint
+    cookie_len: c_uint,
 ) -> c_int
 where
-    F: Fn(&mut SslRef, &[u8]) -> bool + 'static + Sync + Send
+    F: Fn(&mut SslRef, &[u8]) -> bool + 'static + Sync + Send,
 {
     unsafe {
         let ssl_ctx = ffi::SSL_get_SSL_CTX(ssl as *const _);
         let callback = ffi::SSL_CTX_get_ex_data(ssl_ctx, get_callback_idx::<F>());
         let ssl = SslRef::from_ptr_mut(ssl);
         let callback = &*(callback as *mut F);
-        let slice = slice::from_raw_parts(cookie as *const c_uchar as *const u8, cookie_len as usize);
+        let slice =
+            slice::from_raw_parts(cookie as *const c_uchar as *const u8, cookie_len as usize);
         callback(ssl, slice) as c_int
     }
 }