[webcrypto] Add length parameter to HmacKeyAlgorithm. (blink)

Matches a planned change to the spec:
https://www.w3.org/Bugs/Public/show_bug.cgi?id=25094

Chromium side of this change: https://codereview.chromium.org/203303006/

BUG=245025

Review URL: https://codereview.chromium.org/204013006

git-svn-id: svn://svn.chromium.org/blink/trunk@169567 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/crypto/sign-verify-expected.txt

@@ -9,31 +9,37 @@ PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-1'
+PASS tmpKey.algorithm.length is 0
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-256'
+PASS tmpKey.algorithm.length is 0
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-1'
+PASS tmpKey.algorithm.length is 80
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-1'
+PASS tmpKey.algorithm.length is 640
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-256'
+PASS tmpKey.algorithm.length is 320
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS tmpKey.type is 'secret'
 PASS tmpKey.extractable is false
 PASS tmpKey.algorithm.name is 'HMAC'
 PASS tmpKey.algorithm.hash.name is 'SHA-256'
+PASS tmpKey.algorithm.length is 592
 PASS tmpKey.usages.join(',') is 'sign,verify'
 PASS: Mac should be [fbdb1d1b18aa6c08324b7d64b71fb76370690e1d] and was
 PASS: Mac should be [b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad] and was

third_party/WebKit/LayoutTests/crypto/sign-verify.html

@@ -94,6 +94,7 @@ function runSuccessTestCase(testCase)
         shouldBe("tmpKey.extractable", "false")
         shouldBe("tmpKey.algorithm.name", "'HMAC'")
         shouldBe("tmpKey.algorithm.hash.name", "'" + testCase.algorithm + "'")
+        shouldEvaluateTo("tmpKey.algorithm.length", keyData.length * 8);
         shouldBe("tmpKey.usages.join(',')", "'sign,verify'")
 
         // (2) Sign.

third_party/WebKit/Source/modules/crypto/HmacKeyAlgorithm.cpp

@@ -48,6 +48,11 @@ KeyAlgorithm* HmacKeyAlgorithm::hash()
     return m_hash.get();
 }
 
+unsigned HmacKeyAlgorithm::length()
+{
+    return m_algorithm.hmacParams()->lengthBits();
+}
+
 void HmacKeyAlgorithm::trace(Visitor* visitor)
 {
     KeyAlgorithm::trace(visitor);

third_party/WebKit/Source/modules/crypto/HmacKeyAlgorithm.h

@@ -40,6 +40,7 @@ public:
     static PassRefPtrWillBeRawPtr<HmacKeyAlgorithm> create(const blink::WebCryptoKeyAlgorithm&);
 
     KeyAlgorithm* hash();
+    unsigned length();
 
     virtual void trace(Visitor*) OVERRIDE;
 

third_party/WebKit/Source/modules/crypto/HmacKeyAlgorithm.idl

@@ -32,4 +32,5 @@
     NoInterfaceObject
 ] interface HmacKeyAlgorithm : KeyAlgorithm {
   readonly attribute KeyAlgorithm hash;
+  readonly attribute unsigned long length;
 };

third_party/WebKit/public/platform/WebCryptoKeyAlgorithmParams.h

@@ -35,6 +35,9 @@
 #include "WebCryptoAlgorithm.h"
 #include "WebVector.h"
 
+// FIXME: Delete this once the chromium side has picked up the API change.
+#define WEBCRYPTO_HMAC_KEY_HAS_LENGTH 1
+
 namespace blink {
 
 enum WebCryptoKeyAlgorithmParamsType {
@@ -77,8 +80,9 @@ private:
 
 class WebCryptoHmacKeyAlgorithmParams : public WebCryptoKeyAlgorithmParams {
 public:
-    explicit WebCryptoHmacKeyAlgorithmParams(const WebCryptoAlgorithm& hash)
+    WebCryptoHmacKeyAlgorithmParams(const WebCryptoAlgorithm& hash, unsigned lengthBits)
         : m_hash(hash)
+        , m_lengthBits(lengthBits)
     {
     }
 
@@ -87,6 +91,11 @@ public:
         return m_hash;
     }
 
+    unsigned lengthBits() const
+    {
+        return m_lengthBits;
+    }
+
     virtual WebCryptoKeyAlgorithmParamsType type() const
     {
         return WebCryptoKeyAlgorithmParamsTypeHmac;
@@ -94,6 +103,7 @@ public:
 
 private:
     WebCryptoAlgorithm m_hash;
+    unsigned m_lengthBits;
 };
 
 class WebCryptoRsaKeyAlgorithmParams : public WebCryptoKeyAlgorithmParams {