Merge pull request #641 from luser/psk

Expose PSK via a SslContextBuilder::set_psk_callback method

openssl-sys/src/lib.rs

@@ -2262,6 +2262,15 @@ extern "C" {
                                                               arg: *mut c_void)
                                                               -> c_int,
                                             arg: *mut c_void);
+    #[cfg(not(osslconf = "OPENSSL_NO_PSK"))]
+    pub fn SSL_CTX_set_psk_client_callback(ssl: *mut SSL_CTX,
+                                           psk_client_cb: Option<extern "C" fn(*mut SSL,
+                                                                               *const c_char,
+                                                                               *mut c_char,
+                                                                               c_uint,
+                                                                               *mut c_uchar,
+                                                                               c_uint)
+                                                                               -> c_uint>);
     pub fn SSL_select_next_proto(out: *mut *mut c_uchar,
                                  outlen: *mut c_uchar,
                                  inbuf: *const c_uchar,

openssl/src/ssl/mod.rs

@@ -73,7 +73,7 @@
 use ffi;
 use foreign_types::{ForeignType, ForeignTypeRef};
 use libc::{c_int, c_void, c_long, c_ulong};
-use libc::{c_uchar, c_uint};
+use libc::{c_char, c_uchar, c_uint};
 use std::any::Any;
 use std::any::TypeId;
 use std::borrow::Borrow;
@@ -317,6 +317,36 @@ extern "C" fn raw_verify<F>(preverify_ok: c_int, x509_ctx: *mut ffi::X509_STORE_
     }
 }
 
+#[cfg(not(osslconf = "OPENSSL_NO_PSK"))]
+extern "C" fn raw_psk<F>(ssl: *mut ffi::SSL,
+                         hint: *const c_char,
+                         identity: *mut c_char,
+                         max_identity_len: c_uint,
+                         psk: *mut c_uchar,
+                         max_psk_len: c_uint) -> c_uint
+    where F: Fn(&mut SslRef, Option<&[u8]>, &mut [u8], &mut [u8]) -> Result<usize, ErrorStack> + Any + '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 hint = if hint != ptr::null() {
+            Some(CStr::from_ptr(hint).to_bytes())
+        } else {
+            None
+        };
+        // Give the callback mutable slices into which it can write the identity and psk.
+        let identity_sl = slice::from_raw_parts_mut(identity as *mut u8,
+                                                    max_identity_len as usize);
+        let psk_sl = slice::from_raw_parts_mut(psk as *mut u8, max_psk_len as usize);
+        match callback(ssl, hint, identity_sl, psk_sl) {
+            Ok(psk_len) => psk_len as u32,
+            _ => 0,
+        }
+    }
+}
+
 extern "C" fn ssl_raw_verify<F>(preverify_ok: c_int, x509_ctx: *mut ffi::X509_STORE_CTX) -> c_int
     where F: Fn(bool, &X509StoreContextRef) -> bool + Any + 'static + Sync + Send
 {
@@ -987,6 +1017,24 @@ impl SslContextBuilder {
         }
     }
 
+    /// Sets the callback for providing an identity and pre-shared key for a TLS-PSK client.
+    ///
+    /// The callback will be called with the SSL context, an identity hint if one was provided
+    /// by the server, a mut slice for each of the identity and pre-shared key bytes. The identity
+    /// must be written as a null-terminated C string.
+    #[cfg(not(osslconf = "OPENSSL_NO_PSK"))]
+    pub fn set_psk_callback<F>(&mut self, callback: F)
+        where F: Fn(&mut SslRef, Option<&[u8]>, &mut [u8], &mut [u8]) -> Result<usize, ErrorStack> + Any + '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_psk_client_callback(self.as_ptr(), Some(raw_psk::<F>))
+        }
+    }
+
     pub fn build(self) -> SslContext {
         let ctx = SslContext(self.0);
         mem::forget(self);