Bug 1585236 - Have a preference to not be conservative when conneting a proxy, r=dragana

Differential Revision: https://phabricator.services.mozilla.com/D47973

--HG--
extra : moz-landing-system : lando

modules/libpref/init/all.js

@@ -1266,6 +1266,13 @@ pref("network.http.proxy.version", "1.1");    // default
 // pref("network.http.proxy.version", "1.0"); // uncomment this out in case of problems
                                               // (required if using junkbuster proxy)
 
+// Whether we should respect the BE_CONSERVATIVE (aka nsIHttpChannelInternal.beConservative)
+// flag when connecting to a proxy.  If the configured proxy accepts only TLS 1.3, system
+// requests like updates will not pass through.  Setting this pref to false will fix that
+// problem.
+// Default at true to preserve the behavior we had before for backward compat.
+pref("network.http.proxy.respect-be-conservative", true);
+
 // this preference can be set to override the socket type used for normal
 // HTTP traffic.  an empty value indicates the normal TCP/IP socket type.
 pref("network.http.default-socket-type", "");

netwerk/protocol/http/nsHttpConnectionMgr.cpp

@@ -126,6 +126,7 @@ nsHttpConnectionMgr::nsHttpConnectionMgr()
       mThrottleReadInterval(0),
       mThrottleHoldTime(0),
       mThrottleMaxTime(0),
+      mBeConservativeForProxy(true),
       mIsShuttingDown(false),
       mNumActiveConns(0),
       mNumIdleConns(0),
@@ -3003,6 +3004,9 @@ void nsHttpConnectionMgr::OnMsgUpdateParam(int32_t inParam, ARefBase*) {
     case THROTTLING_MAX_TIME:
       mThrottleMaxTime = TimeDuration::FromMilliseconds(value);
       break;
+    case PROXY_BE_CONSERVATIVE:
+      mBeConservativeForProxy = !!value;
+      break;
     default:
       MOZ_ASSERT_UNREACHABLE("unexpected parameter name");
   }
@@ -4013,6 +4017,24 @@ nsHttpConnectionMgr::nsHalfOpenSocket::~nsHalfOpenSocket() {
   if (mEnt) mEnt->RemoveHalfOpen(this);
 }
 
+bool nsHttpConnectionMgr::BeConservativeIfProxied(nsIProxyInfo* proxy) {
+  if (mBeConservativeForProxy) {
+    // The pref says to be conservative for proxies.
+    return true;
+  }
+
+  if (!proxy) {
+    // There is no proxy, so be conservative by default.
+    return true;
+  }
+
+  // Be conservative only if there is no proxy host set either.
+  // This logic was copied from nsSSLIOLayerAddToSocket.
+  nsAutoCString proxyHost;
+  proxy->GetHost(proxyHost);
+  return proxyHost.IsEmpty();
+}
+
 nsresult nsHttpConnectionMgr::nsHalfOpenSocket::SetupStreams(
     nsISocketTransport** transport, nsIAsyncInputStream** instream,
     nsIAsyncOutputStream** outstream, bool isBackup) {
@@ -4085,7 +4107,8 @@ nsresult nsHttpConnectionMgr::nsHalfOpenSocket::SetupStreams(
     tmpFlags |= nsISocketTransport::DONT_TRY_ESNI;
   }
 
-  if ((mCaps & NS_HTTP_BE_CONSERVATIVE) || ci->GetBeConservative()) {
+  if (((mCaps & NS_HTTP_BE_CONSERVATIVE) || ci->GetBeConservative()) &&
+      gHttpHandler->ConnMgr()->BeConservativeIfProxied(ci->ProxyInfo())) {
     LOG(("Setting Socket to BE_CONSERVATIVE"));
     tmpFlags |= nsISocketTransport::BE_CONSERVATIVE;
   }

netwerk/protocol/http/nsHttpConnectionMgr.h

@@ -65,7 +65,8 @@ class nsHttpConnectionMgr final : public nsIObserver, public AltSvcCache {
     THROTTLING_READ_LIMIT,
     THROTTLING_READ_INTERVAL,
     THROTTLING_HOLD_TIME,
-    THROTTLING_MAX_TIME
+    THROTTLING_MAX_TIME,
+    PROXY_BE_CONSERVATIVE
   };
 
   //-------------------------------------------------------------------------
@@ -565,6 +566,7 @@ class nsHttpConnectionMgr final : public nsIObserver, public AltSvcCache {
   uint32_t mThrottleReadInterval;
   uint32_t mThrottleHoldTime;
   TimeDuration mThrottleMaxTime;
+  bool mBeConservativeForProxy;
   Atomic<bool, mozilla::Relaxed> mIsShuttingDown;
 
   //-------------------------------------------------------------------------
@@ -818,6 +820,10 @@ class nsHttpConnectionMgr final : public nsIObserver, public AltSvcCache {
   // Then, it notifies selected transactions' connection of the new active tab
   // id.
   void NotifyConnectionOfWindowIdChange(uint64_t previousWindowId);
+
+  // A test if be-conservative should be used when proxy is setup for the
+  // connection
+  bool BeConservativeIfProxied(nsIProxyInfo* proxy);
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsHttpConnectionMgr::nsHalfOpenSocket,

netwerk/protocol/http/nsHttpHandler.cpp

@@ -1319,6 +1319,16 @@ void nsHttpHandler::PrefsChanged(const char* pref) {
     }
   }
 
+  if (PREF_CHANGED(HTTP_PREF("proxy.respect-be-conservative"))) {
+    rv =
+        Preferences::GetBool(HTTP_PREF("proxy.respect-be-conservative"), &cVar);
+    if (NS_SUCCEEDED(rv) && mConnMgr) {
+      Unused << mConnMgr->UpdateParam(
+          nsHttpConnectionMgr::PROXY_BE_CONSERVATIVE,
+          static_cast<int32_t>(cVar));
+    }
+  }
+
   if (PREF_CHANGED(HTTP_PREF("qos"))) {
     rv = Preferences::GetInt(HTTP_PREF("qos"), &val);
     if (NS_SUCCEEDED(rv)) mQoSBits = (uint8_t)clamped(val, 0, 0xff);