From 18dfc9b6b2509be30a5905b42b6477b9eaf054e2 Mon Sep 17 00:00:00 2001
From: Mike Belopuhov <mike@arcatrust.io>
Date: Fri, 28 Sep 2018 14:43:33 +0200
Subject: [PATCH] Add support for encoding and decoding ECDSA signatures

---
 openssl-sys/src/ec.rs |  8 ++++++++
 openssl/src/ecdsa.rs  | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/openssl-sys/src/ec.rs b/openssl-sys/src/ec.rs
index a33d4d46..d422997a 100644
--- a/openssl-sys/src/ec.rs
+++ b/openssl-sys/src/ec.rs
@@ -200,4 +200,12 @@ extern "C" {
         sig: *const ECDSA_SIG,
         eckey: *mut EC_KEY,
     ) -> c_int;
+
+    pub fn d2i_ECDSA_SIG(
+        sig: *mut *mut ECDSA_SIG,
+        inp: *mut *const c_uchar,
+        length: c_long,
+    ) -> *mut ECDSA_SIG;
+
+    pub fn i2d_ECDSA_SIG(sig: *const ECDSA_SIG, out: *mut *mut c_uchar) -> c_int;
 }
diff --git a/openssl/src/ecdsa.rs b/openssl/src/ecdsa.rs
index 86b42677..ac65c06c 100644
--- a/openssl/src/ecdsa.rs
+++ b/openssl/src/ecdsa.rs
@@ -102,6 +102,25 @@ impl EcdsaSig {
             BigNumRef::from_ptr(s as *mut _)
         }
     }
+
+    from_der! {
+        /// Decodes a DER-encoded ECDSA signature.
+        ///
+        /// This corresponds to [`d2i_ECDSA_SIG`]: https://www.openssl.org/docs/man1.1.0/crypto/d2i_ECDSA_SIG.html
+        from_der,
+        EcdsaSig,
+        ffi::d2i_ECDSA_SIG
+	}
+}
+
+impl EcdsaSigRef {
+    to_der! {
+        /// Serializes the ECDSA signature into a DER-encoded ECDSASignature structure.
+        ///
+        /// This corresponds to [`i2d_ECDSA_SIG`]: https://www.openssl.org/docs/man1.1.0/crypto/i2d_ECDSA_SIG.html
+        to_der,
+        ffi::i2d_ECDSA_SIG
+	}
 }
 
 cfg_if! {
@@ -194,4 +213,21 @@ mod test {
         let verification2 = res2.verify(data.as_bytes(), &public_key).unwrap();
         assert!(verification2);
     }
+
+    #[test]
+    #[cfg_attr(osslconf = "OPENSSL_NO_EC2M", ignore)]
+    fn serialize_deserialize() {
+        let group = EcGroup::from_curve_name(Nid::SECP256K1).unwrap();
+        let private_key = EcKey::generate(&group).unwrap();
+        let public_key = get_public_key(&group, &private_key).unwrap();
+
+        let data = String::from("hello");
+        let res = EcdsaSig::sign(data.as_bytes(), &private_key).unwrap();
+
+        let der = res.to_der().unwrap();
+        let sig = EcdsaSig::from_der(&der).unwrap();
+
+        let verification = sig.verify(data.as_bytes(), &public_key).unwrap();
+        assert!(verification);
+    }
 }