Encode URLs properly (#728)

We were escaping the URL before performing any pattern matching on it.
This meant that if you sent data that URLdecoded to a "/", it would count as
a "/" in the URL, potentially causing a 404. This was causing some flaky tests
with some randomly-generated query parameters.

Now, we keep URLs encoded while doing the pattern matching, and only afterwards
do we URL decode each query parameter individually before passing them to their
respective handler functions.

github.com/gorilla/mux was also updated to v1.7.3 to fix a bug with URL encoding and subrouters.

2 files changed, 36 insertions, 1 deletions

diff --git a/common/basecomponent/base.go b/common/basecomponent/base.go
index d1f50754..6a20aca3 100644
--- a/common/basecomponent/base.go
+++ b/common/basecomponent/base.go
@@ -71,7 +71,7 @@ func NewBaseDendrite(cfg *config.Dendrite, componentName string) *BaseDendrite {
 		componentName: componentName,
 		tracerCloser:  closer,
 		Cfg:           cfg,
-		APIMux:        mux.NewRouter(),
+		APIMux:        mux.NewRouter().UseEncodedPath(),
 		KafkaConsumer: kafkaConsumer,
 		KafkaProducer: kafkaProducer,
 	}
diff --git a/common/routing.go b/common/routing.go
new file mode 100644
index 00000000..330912cd
--- /dev/null
+++ b/common/routing.go
@@ -0,0 +1,35 @@
+// Copyright 2019 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package common
+
+import (
+	"net/url"
+)
+
+// URLDecodeMapValues is a function that iterates through each of the items in a
+// map, URL decodes the value, and returns a new map with the decoded values
+// under the same key names
+func URLDecodeMapValues(vmap map[string]string) (map[string]string, error) {
+	decoded := make(map[string]string, len(vmap))
+	for key, value := range vmap {
+		decodedVal, err := url.QueryUnescape(value)
+		if err != nil {
+			return make(map[string]string), err
+		}
+		decoded[key] = decodedVal
+	}
+
+	return decoded, nil
+}