Issue #1975 - Implement Origin header CSRF mitigation.

Backported from Mozilla bug 446344.

modules/libpref/init/all.js

@@ -1491,6 +1491,10 @@ pref("network.http.referer.XOriginTrimmingPolicy", 0);
 // 0=always send, 1=send iff base domains match, 2=send iff hosts match
 pref("network.http.referer.XOriginPolicy", 0);
 
+// Include an origin header on non-GET and non-HEAD requests regardless of CORS
+// 0=never send, 1=send when same-origin only, 2=always send
+pref("network.http.sendOriginHeader", 0);
+
 // Controls whether referrer attributes in <a>, <img>, <area>, <iframe>, and <link> are honoured
 pref("network.http.enablePerElementReferrer", true);
 

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -1398,22 +1398,10 @@ HttpBaseChannel::SetReferrerWithPolicy(nsIURI *referrer,
     referrer = referrerGrip.get();
   }
 
-  //
-  // block referrer if not on our white list...
-  //
-  static const char *const referrerWhiteList[] = {
-    "http",
-    "https",
-    "ftp",
-    nullptr
-  };
-  match = false;
-  const char *const *scheme = referrerWhiteList;
-  for (; *scheme && !match; ++scheme) {
-    rv = referrer->SchemeIs(*scheme, &match);
-    if (NS_FAILED(rv)) return rv;
+  // Enforce Referrer whitelist
+  if (!IsReferrerSchemeAllowed(referrer)) {
+    return NS_OK; // kick out....
   }
-  if (!match) return NS_OK; // kick out....
 
   //
   // Handle secure referrals.
@@ -2844,6 +2832,24 @@ HttpBaseChannel::AddCookiesToRequest()
   SetRequestHeader(nsDependentCString(nsHttp::Cookie), cookie, false);
 }
 
+/* static */
+bool
+HttpBaseChannel::IsReferrerSchemeAllowed(nsIURI *aReferrer)
+{
+  NS_ENSURE_TRUE(aReferrer, false);
+
+  nsAutoCString scheme;
+  nsresult rv = aReferrer->GetScheme(scheme);
+  NS_ENSURE_SUCCESS(rv, false);
+
+  if (scheme.EqualsIgnoreCase("https") ||
+      scheme.EqualsIgnoreCase("http") ||
+      scheme.EqualsIgnoreCase("ftp")) {
+    return true;
+  }
+  return false;
+}
+
 bool
 HttpBaseChannel::ShouldRewriteRedirectToGET(uint32_t httpStatus,
                                             nsHttpRequestHead::ParsedMethodType method)

netwerk/protocol/http/HttpBaseChannel.h

@@ -319,6 +319,8 @@ public:
 public: /* Necko internal use only... */
     bool IsNavigation();
 
+    static bool IsReferrerSchemeAllowed(nsIURI *aReferrer);
+
     // Return whether upon a redirect code of httpStatus for method, the
     // request method should be rewritten to GET.
     static bool ShouldRewriteRedirectToGET(uint32_t httpStatus,

netwerk/protocol/http/nsHttpAtomList.h

@@ -64,6 +64,7 @@ HTTP_ATOM(Lock_Token,                "Lock-Token")
 HTTP_ATOM(Link,                      "Link")
 HTTP_ATOM(Location,                  "Location")
 HTTP_ATOM(Max_Forwards,              "Max-Forwards")
+HTTP_ATOM(Origin,                    "Origin")
 HTTP_ATOM(Overwrite,                 "Overwrite")
 HTTP_ATOM(Pragma,                    "Pragma")
 HTTP_ATOM(Prefer,                    "Prefer")

netwerk/protocol/http/nsHttpChannel.cpp

@@ -5710,6 +5710,7 @@ nsHttpChannel::BeginConnect()
     mRequestHead.SetHTTPS(isHttps);
     mRequestHead.SetOrigin(scheme, host, port);
 
+    SetOriginHeader();
     SetDoNotTrack();
 
     NeckoOriginAttributes originAttributes;
@@ -7997,6 +7998,58 @@ nsHttpChannel::ResumeInternal()
     return NS_FAILED(rvTransaction) ? rvTransaction : rvCache;
 }
 
+// Step 10 of HTTP-network-or-cache fetch
+void
+nsHttpChannel::SetOriginHeader()
+{
+    if (mRequestHead.IsGet() || mRequestHead.IsHead()) {
+        return;
+    }
+    nsAutoCString existingHeader;
+    Unused << mRequestHead.GetHeader(nsHttp::Origin, existingHeader);
+    if (!existingHeader.IsEmpty()) {
+        LOG(("nsHttpChannel::SetOriginHeader Origin header already present"));
+        return;
+    }
+
+    DebugOnly<nsresult> rv;
+
+    // Instead of consulting Preferences::GetInt() all the time we
+    // can cache the result to speed things up.
+    static int32_t sSendOriginHeader = 0;
+    static bool sIsInited = false;
+    if (!sIsInited) {
+        sIsInited = true;
+        Preferences::AddIntVarCache(&sSendOriginHeader,
+                                    "network.http.sendOriginHeader");
+    }
+    if (sSendOriginHeader == 0) {
+        // Origin header suppressed by user setting
+        return;
+    }
+
+    nsCOMPtr<nsIURI> referrer;
+    mLoadInfo->TriggeringPrincipal()->GetURI(getter_AddRefs(referrer));
+
+    nsAutoCString origin("null");
+    if (referrer && IsReferrerSchemeAllowed(referrer)) {
+        nsContentUtils::GetASCIIOrigin(referrer, origin);
+    }
+
+    // Restrict Origin to same-origin loads if requested by user
+    if (sSendOriginHeader == 1) {
+        nsAutoCString currentOrigin;
+        nsContentUtils::GetASCIIOrigin(mURI, currentOrigin);
+        if (!origin.EqualsIgnoreCase(currentOrigin.get())) {
+            // Origin header suppressed by user setting
+            return;
+        }
+    }
+
+    rv = mRequestHead.SetHeader(nsHttp::Origin, origin, false /* merge */);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+}
+
 void
 nsHttpChannel::SetDoNotTrack()
 {

netwerk/protocol/http/nsHttpChannel.h

@@ -452,6 +452,7 @@ private:
 
     void SetPushedStream(Http2PushedStreamWrapper *stream);
 
+    void SetOriginHeader();
     void SetDoNotTrack();
 
 private: