aws/signer/v4: Fix Signing Unordered Multi Value Query Parameters (aw…

…s#1491)

Removes sorting of query string values when calculating v4 signing as this is not part of the spec:
http://docs.aws.amazon.com/general/latest/gr/sigv4-create-canonical-request.html

The spec only requires the keys, not values, to be sorted which is achieved by Query.Encode().

Also fixed TestBuildCanonicalRequest, which was incorrectly testing without this important part of the build process leading to a false success.

aws/signer/v4/v4.go

@@ -324,10 +324,6 @@ func (v4 Signer) signWithBody(r *http.Request, body io.ReadSeeker, service, regi
 		unsignedPayload:        v4.UnsignedPayload,
 	}
 
-	for key := range ctx.Query {
-		sort.Strings(ctx.Query[key])
-	}
-
 	if ctx.isRequestSigned() {
 		ctx.Time = currentTimeFn()
 		ctx.handlePresignRemoval()

aws/signer/v4/v4_test.go

@@ -128,14 +128,14 @@ func TestPresignRequest(t *testing.T) {
 
 func TestPresignBodyWithArrayRequest(t *testing.T) {
 	req, body := buildRequest("dynamodb", "us-east-1", "{}")
-	req.URL.RawQuery = "Foo=z&Foo=o&Foo=m&Foo=a"
+	req.URL.RawQuery = "FooB=a&FooA=b&FooA=a&FooB=b"
 
 	signer := buildSigner()
 	signer.Presign(req, body, "dynamodb", "us-east-1", 300*time.Second, time.Unix(0, 0))
 
 	expectedDate := "19700101T000000Z"
 	expectedHeaders := "content-length;content-type;host;x-amz-meta-other-header;x-amz-meta-other-header_with_underscore"
-	expectedSig := "fef6002062400bbf526d70f1a6456abc0fb2e213fe1416012737eebd42a62924"
+	expectedSig := "60152079d308a87f036082a236c935261221a32d369ec4b6b75dbc9873d2ab9a"
 	expectedCred := "AKID/19700101/us-east-1/dynamodb/aws4_request"
 	expectedTarget := "prefix.Operation"
 
@@ -519,7 +519,7 @@ func TestSignWithRequestBody_Overwrite(t *testing.T) {
 
 func TestBuildCanonicalRequest(t *testing.T) {
 	req, body := buildRequest("dynamodb", "us-east-1", "{}")
-	req.URL.RawQuery = "Foo=z&Foo=o&Foo=m&Foo=a"
+	req.URL.RawQuery = "FooB=a&FooA=b&FooA=a&FooB=b"
 	ctx := &signingCtx{
 		ServiceName: "dynamodb",
 		Region:      "us-east-1",
@@ -531,7 +531,7 @@ func TestBuildCanonicalRequest(t *testing.T) {
 	}
 
 	ctx.buildCanonicalString()
-	expected := "https://example.org/bucket/key-._~,!@#$%^&*()?Foo=z&Foo=o&Foo=m&Foo=a"
+	expected := "https://example.org/bucket/key-._~,!@#$%^&*()?FooA=b&FooA=a&FooB=a&FooB=b"
 	if e, a := expected, ctx.Request.URL.String(); e != a {
 		t.Errorf("expect %v, got %v", e, a)
 	}