From e04dbfa3ee47741d7f74987803e0a8405550f5f3 Mon Sep 17 00:00:00 2001
From: Benjamin Saunders <ben.e.saunders@gmail.com>
Date: Sun, 25 Feb 2018 19:36:47 -0800
Subject: [PATCH] Expose cookie generate/verify callback setters

---
 openssl/src/ssl/callbacks.rs | 50 ++++++++++++++++++++++++++++++++++++
 openssl/src/ssl/mod.rs       | 45 ++++++++++++++++++++++++++++++++
 2 files changed, 95 insertions(+)

diff --git a/openssl/src/ssl/callbacks.rs b/openssl/src/ssl/callbacks.rs
index c06d32a0..424bdc1a 100644
--- a/openssl/src/ssl/callbacks.rs
+++ b/openssl/src/ssl/callbacks.rs
@@ -361,3 +361,53 @@ where
 
     callback(ssl, line);
 }
+
+pub extern "C" fn raw_cookie_generate<F>(
+    ssl: *mut ffi::SSL,
+    cookie: *mut c_uchar,
+    cookie_len: *mut c_uint
+) -> c_int
+where
+    F: Fn(&mut SslRef, &mut [u8]) -> Result<usize, ErrorStack> + '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);
+        // 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);
+        match callback(ssl, slice) {
+            Ok(len) => {
+                *cookie_len = len as c_uint;
+                1
+            }
+            Err(_) => 0,
+        }
+    }
+}
+
+#[cfg(ossl110)]
+type CookiePtr = *const c_uchar;
+
+#[cfg(not(ossl110))]
+type CookiePtr = *mut c_uchar;
+
+pub extern "C" fn raw_cookie_verify<F>(
+    ssl: *mut ffi::SSL,
+    cookie: CookiePtr,
+    cookie_len: c_uint
+) -> c_int
+where
+    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);
+        callback(ssl, slice) as c_int
+    }
+}
diff --git a/openssl/src/ssl/mod.rs b/openssl/src/ssl/mod.rs
index fb7db988..91b97818 100644
--- a/openssl/src/ssl/mod.rs
+++ b/openssl/src/ssl/mod.rs
@@ -1311,6 +1311,51 @@ impl SslContextBuilder {
         }
     }
 
+    /// Sets the callback for generating an application cookie for stateless handshakes.
+    ///
+    /// The callback will be called with the SSL context and a slice into which the cookie
+    /// should be written. The callback should return the number of bytes written.
+    ///
+    /// This corresponds to `SSL_CTX_set_cookie_generate_cb`.
+    pub fn set_cookie_generate_cb<F>(&mut self, callback: F)
+    where
+        F: Fn(&mut SslRef, &mut [u8]) -> Result<usize, ErrorStack> + 'static + Sync + Send
+    {
+        unsafe {
+            let callback = Box::new(callback);
+            ffi::SSL_CTX_set_ex_data(
+                self.as_ptr(),
+                get_callback_idx::<F>(),
+                mem::transmute(callback),
+            );
+            ffi::SSL_CTX_set_cookie_generate_cb(self.as_ptr(), Some(raw_cookie_generate::<F>))
+        }
+    }
+
+    /// Sets the callback for verifying an application cookie for stateless handshakes.
+    ///
+    /// The callback will be called with the SSL context and the cookie supplied by the
+    /// client. It should return true if and only if the cookie is valid.
+    ///
+    /// Note that the OpenSSL implementation independently verifies the integrity of
+    /// application cookies using an HMAC before invoking the supplied callback.
+    ///
+    /// This corresponds to `SSL_CTX_set_cookie_verify_cb`.
+    pub fn set_cookie_verify_cb<F>(&mut self, callback: F)
+    where
+        F: Fn(&mut SslRef, &[u8]) -> bool + 'static + Sync + Send
+    {
+        unsafe {
+            let callback = Box::new(callback);
+            ffi::SSL_CTX_set_ex_data(
+                self.as_ptr(),
+                get_callback_idx::<F>(),
+                mem::transmute(callback),
+            );
+            ffi::SSL_CTX_set_cookie_verify_cb(self.as_ptr(), Some(raw_cookie_verify::<F>))
+        }
+    }
+
     /// Sets the extra data at the specified index.
     ///
     /// This can be used to provide data to callbacks registered with the context. Use the