From ad2acd36ae071631fe1e12bd4d3b71cdf5c7da88 Mon Sep 17 00:00:00 2001
From: Tim Taubert <ttaubert@mozilla.com>
Date: Tue, 29 Jul 2014 12:37:06 +0200
Subject: [PATCH] Bug 1034855 - Implement deriveKey() for ECDH r=rbarnes

---
 dom/crypto/WebCryptoTask.cpp | 30 +++++++++++++---------
 dom/crypto/test/tests.js     | 48 ++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 11 deletions(-)

diff --git a/dom/crypto/WebCryptoTask.cpp b/dom/crypto/WebCryptoTask.cpp
index ea729ad4daba..e4991aa048cb 100644
--- a/dom/crypto/WebCryptoTask.cpp
+++ b/dom/crypto/WebCryptoTask.cpp
@@ -2327,17 +2327,18 @@ private:
   }
 };
 
-class DerivePbkdfKeyTask : public DerivePbkdfBitsTask
+template<class DeriveBitsTask>
+class DeriveKeyTask : public DeriveBitsTask
 {
 public:
-  DerivePbkdfKeyTask(JSContext* aCx,
-                     const ObjectOrString& aAlgorithm, CryptoKey& aBaseKey,
-                     const ObjectOrString& aDerivedKeyType, bool aExtractable,
-                     const Sequence<nsString>& aKeyUsages)
-    : DerivePbkdfBitsTask(aCx, aAlgorithm, aBaseKey, aDerivedKeyType)
+  DeriveKeyTask(JSContext* aCx,
+                const ObjectOrString& aAlgorithm, CryptoKey& aBaseKey,
+                const ObjectOrString& aDerivedKeyType, bool aExtractable,
+                const Sequence<nsString>& aKeyUsages)
+    : DeriveBitsTask(aCx, aAlgorithm, aBaseKey, aDerivedKeyType)
     , mResolved(false)
   {
-    if (NS_FAILED(mEarlyRv)) {
+    if (NS_FAILED(this->mEarlyRv)) {
       return;
     }
 
@@ -2352,8 +2353,8 @@ protected:
 
 private:
   virtual void Resolve() MOZ_OVERRIDE {
-    mTask->SetKeyData(mResult);
-    mTask->DispatchWithPromise(mResultPromise);
+    mTask->SetKeyData(this->mResult);
+    mTask->DispatchWithPromise(this->mResultPromise);
     mResolved = true;
   }
 
@@ -2737,8 +2738,15 @@ WebCryptoTask::CreateDeriveKeyTask(JSContext* aCx,
   }
 
   if (algName.EqualsASCII(WEBCRYPTO_ALG_PBKDF2)) {
-    return new DerivePbkdfKeyTask(aCx, aAlgorithm, aBaseKey, aDerivedKeyType,
-                                  aExtractable, aKeyUsages);
+    return new DeriveKeyTask<DerivePbkdfBitsTask>(aCx, aAlgorithm, aBaseKey,
+                                                  aDerivedKeyType, aExtractable,
+                                                  aKeyUsages);
+  }
+
+  if (algName.EqualsASCII(WEBCRYPTO_ALG_ECDH)) {
+    return new DeriveKeyTask<DeriveEcdhBitsTask>(aCx, aAlgorithm, aBaseKey,
+                                                 aDerivedKeyType, aExtractable,
+                                                 aKeyUsages);
   }
 
   return new FailureTask(NS_ERROR_DOM_NOT_SUPPORTED_ERR);
diff --git a/dom/crypto/test/tests.js b/dom/crypto/test/tests.js
index 7b4f10ec283d..20f85ba11a3f 100644
--- a/dom/crypto/test/tests.js
+++ b/dom/crypto/test/tests.js
@@ -2143,3 +2143,51 @@ TestArray.addTest(
       .then(error(that), complete(that));
   }
 );
+
+// -----------------------------------------------------------------------------
+TestArray.addTest(
+  "Derive an HMAC key from two ECDH keys and test sign/verify",
+  function() {
+    var that = this;
+    var alg = { name: "ECDH" };
+    var algDerived = { name: "HMAC", hash: {name: "SHA-1"} };
+
+    var pubKey, privKey;
+    function setPub(x) { pubKey = x; }
+    function setPriv(x) { privKey = x; }
+
+    function doDerive() {
+      var alg = { name: "ECDH", public: pubKey };
+      return crypto.subtle.deriveKey(alg, privKey, algDerived, false, ["sign", "verify"])
+        .then(function (x) {
+          if (!hasKeyFields(x)) {
+            throw "Invalid key; missing field(s)";
+          }
+
+          // 512 bit is the default for HMAC-SHA1.
+          if (x.algorithm.length != 512) {
+            throw "Invalid key; incorrect length";
+          }
+
+          return x;
+        });
+    }
+
+    function doSignAndVerify(x) {
+      var data = crypto.getRandomValues(new Uint8Array(1024));
+      return crypto.subtle.sign("HMAC", x, data)
+        .then(function (sig) {
+          return crypto.subtle.verify("HMAC", x, sig, data);
+        });
+    }
+
+    Promise.all([
+      crypto.subtle.importKey("jwk", tv.ecdh_p521.jwk_priv, alg, false, ["deriveBits"])
+        .then(setPriv, error(that)),
+      crypto.subtle.importKey("jwk", tv.ecdh_p521.jwk_pub, alg, false, ["deriveBits"])
+        .then(setPub, error(that))
+    ]).then(doDerive, error(that))
+      .then(doSignAndVerify, error(that))
+      .then(complete(that), error(that));
+  }
+);