detect redirection loops in acquire instead of workers

Having the detection handled in specific (http) workers means that a
redirection loop over different hostnames isn't detected. Its also not a
good idea have this implement in each method independently even if it
would work

apt-pkg/acquire-item.cc

@@ -685,10 +685,15 @@ class APT_HIDDEN CleanupItem : public pkgAcqTransactionItem		/*{{{*/
 									/*}}}*/
 
 // Acquire::Item::Item - Constructor					/*{{{*/
+class pkgAcquire::Item::Private
+{
+public:
+   std::vector<std::string> PastRedirections;
+};
 APT_IGNORE_DEPRECATED_PUSH
 pkgAcquire::Item::Item(pkgAcquire * const owner) :
    FileSize(0), PartialSize(0), Mode(0), ID(0), Complete(false), Local(false),
-    QueueCounter(0), ExpectedAdditionalItems(0), Owner(owner), d(NULL)
+    QueueCounter(0), ExpectedAdditionalItems(0), Owner(owner), d(new Private())
 {
    Owner->Add(this);
    Status = StatIdle;
@@ -699,6 +704,7 @@ APT_IGNORE_DEPRECATED_POP
 pkgAcquire::Item::~Item()
 {
    Owner->Remove(this);
+   delete d;
 }
 									/*}}}*/
 std::string pkgAcquire::Item::Custom600Headers() const			/*{{{*/
@@ -766,32 +772,40 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
    }
 
    string const FailReason = LookupTag(Message, "FailReason");
-   enum { MAXIMUM_SIZE_EXCEEDED, HASHSUM_MISMATCH, WEAK_HASHSUMS, OTHER } failreason = OTHER;
+   enum { MAXIMUM_SIZE_EXCEEDED, HASHSUM_MISMATCH, WEAK_HASHSUMS, REDIRECTION_LOOP, OTHER } failreason = OTHER;
    if ( FailReason == "MaximumSizeExceeded")
       failreason = MAXIMUM_SIZE_EXCEEDED;
    else if ( FailReason == "WeakHashSums")
       failreason = WEAK_HASHSUMS;
+   else if (FailReason == "RedirectionLoop")
+      failreason = REDIRECTION_LOOP;
    else if (Status == StatAuthError)
       failreason = HASHSUM_MISMATCH;
 
    if(ErrorText.empty())
    {
+      std::ostringstream out;
+      switch (failreason)
+      {
+	 case HASHSUM_MISMATCH:
+	    out << _("Hash Sum mismatch") << std::endl;
+	    break;
+	 case WEAK_HASHSUMS:
+	    out << _("Insufficient information available to perform this download securely") << std::endl;
+	    break;
+	 case REDIRECTION_LOOP:
+	    out << "Redirection loop encountered" << std::endl;
+	    break;
+	 case MAXIMUM_SIZE_EXCEEDED:
+	    out << LookupTag(Message, "Message") << std::endl;
+	    break;
+	 case OTHER:
+	    out << LookupTag(Message, "Message");
+	    break;
+      }
+
       if (Status == StatAuthError)
       {
-	 std::ostringstream out;
-	 switch (failreason)
-	 {
-	    case HASHSUM_MISMATCH:
-	       out << _("Hash Sum mismatch") << std::endl;
-	       break;
-	    case WEAK_HASHSUMS:
-	       out << _("Insufficient information available to perform this download securely") << std::endl;
-	       break;
-	    case MAXIMUM_SIZE_EXCEEDED:
-	    case OTHER:
-	       out << LookupTag(Message, "Message") << std::endl;
-	       break;
-	 }
 	 auto const ExpectedHashes = GetExpectedHashes();
 	 if (ExpectedHashes.empty() == false)
 	 {
@@ -822,10 +836,8 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
 	    }
 	    out << "Last modification reported: " << LookupTag(Message, "Last-Modified", "<none>") << std::endl;
 	 }
-	 ErrorText = out.str();
       }
-      else
-	 ErrorText = LookupTag(Message,"Message");
+      ErrorText = out.str();
    }
 
    switch (failreason)
@@ -833,6 +845,7 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
       case MAXIMUM_SIZE_EXCEEDED: RenameOnError(MaximumSizeExceeded); break;
       case HASHSUM_MISMATCH: RenameOnError(HashSumMismatch); break;
       case WEAK_HASHSUMS: break;
+      case REDIRECTION_LOOP: break;
       case OTHER: break;
    }
 
@@ -976,6 +989,24 @@ std::string pkgAcquire::Item::HashSum() const				/*{{{*/
    return hs != NULL ? hs->toStr() : "";
 }
 									/*}}}*/
+bool pkgAcquire::Item::IsRedirectionLoop(std::string const &NewURI)	/*{{{*/
+{
+   if (d->PastRedirections.empty())
+   {
+      d->PastRedirections.push_back(NewURI);
+      return false;
+   }
+   auto const LastURI = std::prev(d->PastRedirections.end());
+   // redirections to the same file are a way of restarting/resheduling,
+   // individual methods will have to make sure that they aren't looping this way
+   if (*LastURI == NewURI)
+      return false;
+   if (std::find(d->PastRedirections.begin(), LastURI, NewURI) != LastURI)
+      return true;
+   d->PastRedirections.push_back(NewURI);
+   return false;
+}
+									/*}}}*/
 
 pkgAcqTransactionItem::pkgAcqTransactionItem(pkgAcquire * const Owner,	/*{{{*/
       pkgAcqMetaClearSig * const transactionManager, IndexTarget const &target) :

apt-pkg/acquire-item.h

@@ -304,6 +304,8 @@ class pkgAcquire::Item : public WeakPointable				/*{{{*/
     */
    virtual ~Item();
 
+   bool APT_HIDDEN IsRedirectionLoop(std::string const &NewURI);
+
    protected:
    /** \brief The acquire object with which this item is associated. */
    pkgAcquire * const Owner;
@@ -357,7 +359,8 @@ class pkgAcquire::Item : public WeakPointable				/*{{{*/
    virtual std::string GetFinalFilename() const;
 
    private:
-   void * const d;
+   class Private;
+   Private * const d;
 
    friend class pkgAcqMetaBase;
    friend class pkgAcqMetaClearSig;

apt-pkg/acquire-worker.cc

@@ -269,6 +269,16 @@ bool pkgAcquire::Worker::RunMessages()
 	    for (auto const &Owner: ItmOwners)
 	    {
 	       pkgAcquire::ItemDesc &desc = Owner->GetItemDesc();
+	       if (Owner->IsRedirectionLoop(NewURI))
+	       {
+		  std::string msg = Message;
+		  msg.append("\nFailReason: RedirectionLoop");
+		  Owner->Failed(msg, Config);
+		  if (Log != nullptr)
+		     Log->Fail(Owner->GetItemDesc());
+		  continue;
+	       }
+
 	       if (Log != nullptr)
 		  Log->Done(desc);
 

methods/aptmethod.h

@@ -17,7 +17,8 @@
 
 class aptMethod : public pkgAcqMethod
 {
-   char const * const Binary;
+protected:
+   std::string Binary;
 
 public:
    virtual bool Configuration(std::string Message) APT_OVERRIDE

methods/http.cc

@@ -465,6 +465,12 @@ bool HttpServerState::RunData(FileFd * const File)
    return Owner->Flush() && !_error->PendingError();
 }
 									/*}}}*/
+bool HttpServerState::RunDataToDevNull()				/*{{{*/
+{
+   FileFd DevNull("/dev/null", FileFd::WriteOnly);
+   return RunData(&DevNull);
+}
+									/*}}}*/
 bool HttpServerState::ReadHeaderLines(std::string &Data)		/*{{{*/
 {
    return In.WriteTillEl(Data);

methods/http.h

@@ -106,6 +106,7 @@ struct HttpServerState: public ServerState
    virtual void Reset() APT_OVERRIDE { ServerState::Reset(); ServerFd = -1; };
 
    virtual bool RunData(FileFd * const File) APT_OVERRIDE;
+   virtual bool RunDataToDevNull() APT_OVERRIDE;
 
    virtual bool Open() APT_OVERRIDE;
    virtual bool IsOpen() APT_OVERRIDE;

methods/https.h

@@ -39,6 +39,7 @@ class HttpsServerState : public ServerState
 
    /** \brief Transfer the data from the socket */
    virtual bool RunData(FileFd * const /*File*/) APT_OVERRIDE { return false; }
+   virtual bool RunDataToDevNull() APT_OVERRIDE { return false; }
 
    virtual bool Open() APT_OVERRIDE { return false; }
    virtual bool IsOpen() APT_OVERRIDE { return false; }

methods/server.cc

@@ -297,12 +297,33 @@ ServerMethod::DealWithHeaders(FetchResult &Res)
 	 else
 	    NextURI.clear();
 	 NextURI.append(DeQuoteString(Server->Location));
+	 if (Queue->Uri == NextURI)
+	 {
+	    SetFailReason("RedirectionLoop");
+	    _error->Error("Redirection loop encountered");
+	    if (Server->HaveContent == true)
+	       return ERROR_WITH_CONTENT_PAGE;
+	    return ERROR_UNRECOVERABLE;
+	 }
 	 return TRY_AGAIN_OR_REDIRECT;
       }
       else
       {
 	 NextURI = DeQuoteString(Server->Location);
 	 URI tmpURI = NextURI;
+	 if (tmpURI.Access == "http" && Binary == "https+http")
+	 {
+	    tmpURI.Access = "https+http";
+	    NextURI = tmpURI;
+	 }
+	 if (Queue->Uri == NextURI)
+	 {
+	    SetFailReason("RedirectionLoop");
+	    _error->Error("Redirection loop encountered");
+	    if (Server->HaveContent == true)
+	       return ERROR_WITH_CONTENT_PAGE;
+	    return ERROR_UNRECOVERABLE;
+	 }
 	 URI Uri = Queue->Uri;
 	 // same protocol redirects are okay
 	 if (tmpURI.Access == Uri.Access)
@@ -486,10 +507,6 @@ bool ServerMethod::Fetch(FetchItem *)
 // ServerMethod::Loop - Main loop					/*{{{*/
 int ServerMethod::Loop()
 {
-   typedef vector<string> StringVector;
-   typedef vector<string>::iterator StringVectorIterator;
-   map<string, StringVector> Redirected;
-
    signal(SIGTERM,SigTerm);
    signal(SIGINT,SigTerm);
    
@@ -720,46 +737,16 @@ int ServerMethod::Loop()
 	    File = 0;
 	    break;
 	 }
-	 
-         // Try again with a new URL
-         case TRY_AGAIN_OR_REDIRECT:
-         {
-            // Clear rest of response if there is content
-            if (Server->HaveContent)
-            {
-               File = new FileFd("/dev/null",FileFd::WriteExists);
-               Server->RunData(File);
-               delete File;
-               File = 0;
-            }
-
-            /* Detect redirect loops.  No more redirects are allowed
-               after the same URI is seen twice in a queue item. */
-            StringVector &R = Redirected[Queue->DestFile];
-            bool StopRedirects = false;
-            if (R.empty() == true)
-               R.push_back(Queue->Uri);
-            else if (R[0] == "STOP" || R.size() > 10)
-               StopRedirects = true;
-            else
-            {
-               for (StringVectorIterator I = R.begin(); I != R.end(); ++I)
-                  if (Queue->Uri == *I)
-                  {
-                     R[0] = "STOP";
-                     break;
-                  }
- 
-               R.push_back(Queue->Uri);
-            }
- 
-            if (StopRedirects == false)
-               Redirect(NextURI);
-            else
-               Fail();
- 
-            break;
-         }
+
+	 // Try again with a new URL
+	 case TRY_AGAIN_OR_REDIRECT:
+	 {
+	    // Clear rest of response if there is content
+	    if (Server->HaveContent)
+	       Server->RunDataToDevNull();
+	    Redirect(NextURI);
+	    break;
+	 }
 
 	 default:
 	 Fail(_("Internal error"));

methods/server.h

@@ -91,6 +91,7 @@ struct ServerState
 
    /** \brief Transfer the data from the socket */
    virtual bool RunData(FileFd * const File) = 0;
+   virtual bool RunDataToDevNull() = 0;
 
    virtual bool Open() = 0;
    virtual bool IsOpen() = 0;

test/integration/test-apt-redirect-loop

@@ -0,0 +1,23 @@
+#!/bin/sh
+set -e
+
+TESTDIR="$(readlink -f "$(dirname "$0")")"
+. "$TESTDIR/framework"
+
+setupenvironment
+configarchitecture "i386"
+
+insertpackage 'stable' 'apt' 'all' '1'
+setupaptarchive --no-update
+
+echo 'alright' > aptarchive/working
+changetohttpswebserver
+webserverconfig 'aptwebserver::redirect::replace::/redirectme3/' '/redirectme/'
+webserverconfig 'aptwebserver::redirect::replace::/redirectme2/' '/redirectme3/'
+webserverconfig 'aptwebserver::redirect::replace::/redirectme/' '/redirectme2/'
+
+testfailure apthelper download-file "http://localhost:${APTHTTPPORT}/redirectme/working" httpfile
+testsuccess grep 'Redirection loop encountered' rootdir/tmp/testfailure.output
+
+testfailure apthelper download-file "https://localhost:${APTHTTPSPORT}/redirectme/working" httpsfile
+testsuccess grep 'Redirection loop encountered' rootdir/tmp/testfailure.output