Bug 1398646: Forbid sync DNS resolution on the main thread. r=valentin

MozReview-Commit-ID: A6mUDNSri2m

--HG--
extra : rebase_source : 43c58d61614e186b89523a301fd1d2d8bd99a503
extra : source : 963bf9d8573273894016e7082cb5f3fb85d80661

extensions/auth/moz.build

@@ -24,6 +24,10 @@ else:
         'nsAuthSambaNTLM.cpp',
     ]
 
+LOCAL_INCLUDES += [
+    '/netwerk/dns', # For nsDNSService2.h
+]
+
 FINAL_LIBRARY = 'xul'
 
 with Files('**'):

extensions/auth/nsAuthSSPI.cpp

@@ -14,6 +14,7 @@
 //
 
 #include "nsAuthSSPI.h"
+#include "nsDNSService2.h"
 #include "nsIServiceManager.h"
 #include "nsIDNSService.h"
 #include "nsIDNSRecord.h"
@@ -92,8 +93,8 @@ InitSSPI()
 
 //-----------------------------------------------------------------------------
 
-static nsresult
-MakeSN(const char *principal, nsCString &result)
+nsresult
+nsAuthSSPI::MakeSN(const char *principal, nsCString &result)
 {
     nsresult rv;
 
@@ -106,10 +107,12 @@ MakeSN(const char *principal, nsCString &result)
     if (index == kNotFound)
         return NS_ERROR_UNEXPECTED;
 
-    nsCOMPtr<nsIDNSService> dns = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
+    nsCOMPtr<nsIDNSService> dnsService = do_GetService(NS_DNSSERVICE_CONTRACTID, &rv);
     if (NS_FAILED(rv))
         return rv;
 
+    auto dns = static_cast<nsDNSService*>(dnsService.get());
+
     // This could be expensive if our DNS cache cannot satisfy the request.
     // However, we should have at least hit the OS resolver once prior to
     // reaching this code, so provided the OS resolver has this information
@@ -120,10 +123,10 @@ MakeSN(const char *principal, nsCString &result)
     // its cache.  This is not an issue in versions of Windows up to WinXP.
     nsCOMPtr<nsIDNSRecord> record;
     mozilla::OriginAttributes attrs;
-    rv = dns->ResolveNative(Substring(buf, index + 1),
-                            nsIDNSService::RESOLVE_CANONICAL_NAME,
-                            attrs,
-                            getter_AddRefs(record));
+    rv = dns->DeprecatedSyncResolve(Substring(buf, index + 1),
+                                    nsIDNSService::RESOLVE_CANONICAL_NAME,
+                                    attrs,
+                                    getter_AddRefs(record));
     if (NS_FAILED(rv))
         return rv;
 

extensions/auth/nsAuthSSPI.h

@@ -42,6 +42,8 @@ private:
     typedef TimeStamp MS_TimeStamp;
 
 private:
+    nsresult MakeSN(const char *principal, nsCString &result);
+
     CredHandle   mCred;
     CtxtHandle   mCtxt;
     nsCString    mServiceName;

netwerk/dns/nsDNSService2.cpp

@@ -991,6 +991,29 @@ nsDNSService::ResolveNative(const nsACString        &aHostname,
                             uint32_t                 flags,
                             const OriginAttributes  &aOriginAttributes,
                             nsIDNSRecord           **result)
+{
+    // Synchronous resolution is not available on the main thread.
+    if (NS_IsMainThread()) {
+        return NS_ERROR_NOT_AVAILABLE;
+    }
+
+    return ResolveInternal(aHostname, flags, aOriginAttributes, result);
+}
+
+nsresult
+nsDNSService::DeprecatedSyncResolve(const nsACString        &aHostname,
+                                    uint32_t                 flags,
+                                    const OriginAttributes  &aOriginAttributes,
+                                    nsIDNSRecord           **result)
+{
+    return ResolveInternal(aHostname, flags, aOriginAttributes, result);
+}
+
+nsresult
+nsDNSService::ResolveInternal(const nsACString        &aHostname,
+                              uint32_t                 flags,
+                              const OriginAttributes  &aOriginAttributes,
+                              nsIDNSRecord           **result)
 {
     // grab reference to global host resolver and IDN service.  beware
     // simultaneous shutdown!!

netwerk/dns/nsDNSService2.h

@@ -19,6 +19,8 @@
 #include "mozilla/Mutex.h"
 #include "mozilla/Attributes.h"
 
+class nsAuthSSPI;
+
 class nsDNSService final : public nsPIDNSService
                          , public nsIObserver
                          , public nsIMemoryReporter
@@ -38,6 +40,14 @@ public:
 
     bool GetOffline() const;
 
+protected:
+    friend class nsAuthSSPI;
+
+    nsresult DeprecatedSyncResolve(const nsACString &aHostname,
+                                   uint32_t flags,
+                                   const mozilla::OriginAttributes &aOriginAttributes,
+                                   nsIDNSRecord **result);
+
 private:
     ~nsDNSService();
 
@@ -50,6 +60,11 @@ private:
                                 nsIIDNService    *aIDN,
                                 nsACString       &aACE);
 
+    nsresult ResolveInternal(const nsACString &aHostname,
+                             uint32_t flags,
+                             const mozilla::OriginAttributes &aOriginAttributes,
+                             nsIDNSRecord **result);
+
     RefPtr<nsHostResolver>  mResolver;
     nsCOMPtr<nsIIDNService>   mIDN;
 

netwerk/dns/nsIDNSService.idl

@@ -99,9 +99,10 @@ interface nsIDNSService : nsISupports
                                       in OriginAttributes  aOriginAttributes);
 
     /**
-     * called to synchronously resolve a hostname.  warning this method may
-     * block the calling thread for a long period of time.  it is extremely
-     * unwise to call this function on the UI thread of an application.
+     * called to synchronously resolve a hostname.
+     *
+     * Since this method may block the calling thread for a long period of
+     * time, it may not be accessed from the main thread.
      *
      * @param aHostName
      *        the hostname or IP-address-literal to resolve.
@@ -114,6 +115,7 @@ interface nsIDNSService : nsISupports
      *
      * @return DNS record corresponding to the given hostname.
      * @throws NS_ERROR_UNKNOWN_HOST if host could not be resolved.
+     * @throws NS_ERROR_NOT_AVAILABLE if accessed from the main thread.
      */
     [implicit_jscontext, optional_argc]
     nsIDNSRecord resolve(in AUTF8String   aHostName,