Fix SslContext::add_extra_chain_cert

SSL_CTX_add_extra_chain_cert assumes ownership of the certificate, so
the method really needs to take an X509 by value. Work around this by
manually cloning the cert.

This method has been around for over a year but I'm guessing nobody
actually used it since it produces a nice double free into segfault!

3 files changed, 27 insertions, 3 deletions

diff --git a/openssl/src/ssl/mod.rs b/openssl/src/ssl/mod.rs
index 64a2ccaf..6e365af6 100644
--- a/openssl/src/ssl/mod.rs
+++ b/openssl/src/ssl/mod.rs
@@ -535,9 +535,14 @@ impl<'a> SslContextRef<'a> {
     /// Adds a certificate to the certificate chain presented together with the
     /// certificate specified using set_certificate()
     pub fn add_extra_chain_cert(&mut self, cert: &X509Ref) -> Result<(), ErrorStack> {
-        wrap_ssl_result(unsafe {
-            ffi::SSL_CTX_add_extra_chain_cert(self.as_ptr(), cert.as_ptr()) as c_int
-        })
+        // FIXME this should really just take an X509 by value
+        let der = try!(cert.to_der());
+        let cert = try!(X509::from_der(&der));
+        unsafe {
+            try_ssl!(ffi::SSL_CTX_add_extra_chain_cert(self.as_ptr(), cert.as_ptr()));
+        }
+        mem::forget(cert);
+        Ok(())
     }
 
     /// Specifies the file that contains private key
diff --git a/openssl/src/ssl/tests/mod.rs b/openssl/src/ssl/tests/mod.rs
index 2881d4fe..3bbbed03 100644
--- a/openssl/src/ssl/tests/mod.rs
+++ b/openssl/src/ssl/tests/mod.rs
@@ -1081,3 +1081,11 @@ fn default_verify_paths() {
     assert!(result.starts_with(b"HTTP/1.0"));
     assert!(result.ends_with(b"</HTML>\r\n") || result.ends_with(b"</html>"));
 }
+
+#[test]
+fn add_extra_chain_cert() {
+    let cert = include_bytes!("../../../test/cert.pem");
+    let cert = X509::from_pem(cert).unwrap();
+    let mut ctx = SslContext::new(SslMethod::Sslv23).unwrap();
+    ctx.add_extra_chain_cert(&cert).unwrap();
+}
diff --git a/openssl/src/x509/mod.rs b/openssl/src/x509/mod.rs
index 1319b75c..f5369447 100644
--- a/openssl/src/x509/mod.rs
+++ b/openssl/src/x509/mod.rs
@@ -1,4 +1,5 @@
 use libc::{c_char, c_int, c_long, c_ulong, c_void};
+use std::cmp;
 use std::ffi::CString;
 use std::mem;
 use std::ptr;
@@ -492,6 +493,16 @@ impl X509 {
         X509::from_ptr(x509)
     }
 
+    /// Reads a certificate from DER.
+    pub fn from_der(buf: &[u8]) -> Result<X509, ErrorStack> {
+        unsafe {
+            let mut ptr = buf.as_ptr() as *mut _;
+            let len = cmp::min(buf.len(), c_long::max_value() as usize) as c_long;
+            let x509 = try_ssl_null!(ffi::d2i_X509(ptr::null_mut(), &mut ptr, len));
+            Ok(X509::from_ptr(x509))
+        }
+    }
+
     /// Reads a certificate from PEM.
     pub fn from_pem(buf: &[u8]) -> Result<X509, ErrorStack> {
         let mem_bio = try!(MemBioSlice::new(buf));