]> git.saurik.com Git - apt.git/blobdiff - apt-pkg/acquire-item.cc
Wreck validation until we can assess ecosystem :/.
[apt.git] / apt-pkg / acquire-item.cc
index 959627a01ed2a6111568767e05ff5b388f31ae70..663452b9f1c92451c72ac5008f46e4c0c83411f4 100644 (file)
@@ -46,6 +46,7 @@
 #include <ctime>
 #include <sstream>
 #include <numeric>
+#include <random>
 
 #include <apti18n.h>
                                                                        /*}}}*/
@@ -145,7 +146,7 @@ static void ReportMirrorFailureToCentral(pkgAcquire::Item const &I, std::string
             << FailCode << std::endl;
 #endif
    string const report = _config->Find("Methods::Mirror::ProblemReporting",
-                                "/usr/lib/apt/apt-report-mirror-failure");
+                                LIBEXEC_DIR "/apt-report-mirror-failure");
    if(!FileExists(report))
       return;
 
@@ -175,41 +176,101 @@ static void ReportMirrorFailureToCentral(pkgAcquire::Item const &I, std::string
 }
                                                                        /*}}}*/
 
-static bool MessageInsecureRepository(bool const isError, std::string const &msg)/*{{{*/
+static APT_NONNULL(2) bool MessageInsecureRepository(bool const isError, char const * const msg, std::string const &repo)/*{{{*/
 {
+   std::string m;
+   strprintf(m, msg, repo.c_str());
    if (isError)
    {
-      _error->Error("%s", msg.c_str());
+      _error->Error("%s", m.c_str());
       _error->Notice("%s", _("Updating from such a repository can't be done securely, and is therefore disabled by default."));
    }
    else
    {
-      _error->Warning("%s", msg.c_str());
+      _error->Warning("%s", m.c_str());
       _error->Notice("%s", _("Data from such a repository can't be authenticated and is therefore potentially dangerous to use."));
    }
    _error->Notice("%s", _("See apt-secure(8) manpage for repository creation and user configuration details."));
    return false;
 }
-static bool APT_NONNULL(2) MessageInsecureRepository(bool const isError, char const * const msg, std::string const &repo)
+                                                                       /*}}}*/
+// AllowInsecureRepositories                                           /*{{{*/
+enum class InsecureType { UNSIGNED, WEAK, NORELEASE };
+static bool TargetIsAllowedToBe(IndexTarget const &Target, InsecureType const type)
 {
-   std::string m;
-   strprintf(m, msg, repo.c_str());
-   return MessageInsecureRepository(isError, m);
+   if (_config->FindB("Acquire::AllowInsecureRepositories"))
+      return true;
+
+   if (Target.OptionBool(IndexTarget::ALLOW_INSECURE))
+      return true;
+
+   switch (type)
+   {
+      case InsecureType::UNSIGNED: break;
+      case InsecureType::NORELEASE: break;
+      case InsecureType::WEAK:
+        if (_config->FindB("Acquire::AllowWeakRepositories"))
+           return true;
+        if (Target.OptionBool(IndexTarget::ALLOW_WEAK))
+           return true;
+        break;
+   }
+   return false;
 }
-                                                                       /*}}}*/
-static bool APT_NONNULL(1, 3, 4, 5) AllowInsecureRepositories(char const * const msg, std::string const &repo,/*{{{*/
+static bool APT_NONNULL(3, 4, 5) AllowInsecureRepositories(InsecureType const msg, std::string const &repo,
       metaIndex const * const MetaIndexParser, pkgAcqMetaClearSig * const TransactionManager, pkgAcquire::Item * const I)
 {
+   // we skip weak downgrades as its unlikely that a repository gets really weaker –
+   // its more realistic that apt got pickier in a newer version
+   if (msg != InsecureType::WEAK)
+   {
+      std::string const FinalInRelease = TransactionManager->GetFinalFilename();
+      std::string const FinalReleasegpg = FinalInRelease.substr(0, FinalInRelease.length() - strlen("InRelease")) + "Release.gpg";
+      if (RealFileExists(FinalReleasegpg) || RealFileExists(FinalInRelease))
+      {
+        char const * msgstr = nullptr;
+        switch (msg)
+        {
+           case InsecureType::UNSIGNED: msgstr = _("The repository '%s' is no longer signed."); break;
+           case InsecureType::NORELEASE: msgstr = _("The repository '%s' does no longer have a Release file."); break;
+           case InsecureType::WEAK: /* unreachable */ break;
+        }
+        if (_config->FindB("Acquire::AllowDowngradeToInsecureRepositories") ||
+              TransactionManager->Target.OptionBool(IndexTarget::ALLOW_DOWNGRADE_TO_INSECURE))
+        {
+           // meh, the users wants to take risks (we still mark the packages
+           // from this repository as unauthenticated)
+           _error->Warning(msgstr, repo.c_str());
+           _error->Warning(_("This is normally not allowed, but the option "
+                    "Acquire::AllowDowngradeToInsecureRepositories was "
+                    "given to override it."));
+        } else {
+           MessageInsecureRepository(true, msgstr, repo);
+           TransactionManager->AbortTransaction();
+           I->Status = pkgAcquire::Item::StatError;
+           return false;
+        }
+      }
+   }
+
    if(MetaIndexParser->GetTrusted() == metaIndex::TRI_YES)
       return true;
 
-   if (_config->FindB("Acquire::AllowInsecureRepositories") == true)
+   char const * msgstr = nullptr;
+   switch (msg)
    {
-      MessageInsecureRepository(false, msg, repo);
+      case InsecureType::UNSIGNED: msgstr = _("The repository '%s' is not signed."); break;
+      case InsecureType::NORELEASE: msgstr = _("The repository '%s' does not have a Release file."); break;
+      case InsecureType::WEAK: msgstr = _("The repository '%s' provides only weak security information."); break;
+   }
+
+   if (TargetIsAllowedToBe(TransactionManager->Target, msg) == true)
+   {
+      //MessageInsecureRepository(false, msgstr, repo);
       return true;
    }
 
-   MessageInsecureRepository(true, msg, repo);
+   MessageInsecureRepository(true, msgstr, repo);
    TransactionManager->AbortTransaction();
    I->Status = pkgAcquire::Item::StatError;
    return false;
@@ -239,7 +300,20 @@ APT_CONST bool pkgAcqTransactionItem::HashesRequired() const
       we can at least trust them for integrity of the download itself.
       Only repositories without a Release file can (obviously) not have
       hashes – and they are very uncommon and strongly discouraged */
-   return TransactionManager->MetaIndexParser->GetLoadedSuccessfully() == metaIndex::TRI_YES;
+   if (TransactionManager->MetaIndexParser->GetLoadedSuccessfully() != metaIndex::TRI_YES)
+      return false;
+   if (TargetIsAllowedToBe(Target, InsecureType::WEAK))
+   {
+      /* If we allow weak hashes, we check that we have some (weak) and then
+         declare hashes not needed. That will tip us in the right direction
+        as if hashes exist, they will be used, even if not required */
+      auto const hsl = GetExpectedHashes();
+      if (hsl.usable())
+        return true;
+      if (hsl.empty() == false)
+        return false;
+   }
+   return true;
 }
 HashStringList pkgAcqTransactionItem::GetExpectedHashes() const
 {
@@ -337,7 +411,7 @@ bool pkgAcqTransactionItem::QueueURI(pkgAcquire::ItemDesc &Item)
       return false;
    }
    // If we got the InRelease file via a mirror, pick all indexes directly from this mirror, too
-   if (TransactionManager->BaseURI.empty() == false &&
+   if (TransactionManager->BaseURI.empty() == false && UsedMirror.empty() &&
         URI::SiteOnly(Item.URI) != URI::SiteOnly(TransactionManager->BaseURI))
    {
       // this ensures we rewrite only once and only the first step
@@ -378,7 +452,11 @@ std::string pkgAcquire::Item::GetFinalFilename() const
 }
 std::string pkgAcqDiffIndex::GetFinalFilename() const
 {
-   return GetFinalFileNameFromURI(GetDiffIndexURI(Target));
+   std::string const FinalFile = GetFinalFileNameFromURI(GetDiffIndexURI(Target));
+   // we don't want recompress, so lets keep whatever we got
+   if (CurrentCompressionExtension == "uncompressed")
+      return FinalFile;
+   return FinalFile + "." + CurrentCompressionExtension;
 }
 std::string pkgAcqIndex::GetFinalFilename() const
 {
@@ -415,7 +493,10 @@ std::string pkgAcqIndex::GetMetaKey() const
 }
 std::string pkgAcqDiffIndex::GetMetaKey() const
 {
-   return GetDiffIndexFileName(Target.MetaKey);
+   auto const metakey = GetDiffIndexFileName(Target.MetaKey);
+   if (CurrentCompressionExtension == "uncompressed")
+      return metakey;
+   return metakey + "." + CurrentCompressionExtension;
 }
                                                                        /*}}}*/
 //pkgAcqTransactionItem::TransactionState and specialisations for child classes        /*{{{*/
@@ -612,10 +693,15 @@ 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;
@@ -626,6 +712,7 @@ APT_IGNORE_DEPRECATED_POP
 pkgAcquire::Item::~Item()
 {
    Owner->Remove(this);
+   delete d;
 }
                                                                        /*}}}*/
 std::string pkgAcquire::Item::Custom600Headers() const                 /*{{{*/
@@ -661,6 +748,18 @@ APT_CONST bool pkgAcquire::Item::IsTrusted() const                 /*{{{*/
 // ---------------------------------------------------------------------
 /* We return to an idle state if there are still other queues that could
    fetch this object */
+static void formatHashsum(std::ostream &out, HashString const &hs)
+{
+   auto const type = hs.HashType();
+   if (type == "Checksum-FileSize")
+      out << " - Filesize";
+   else
+      out << " - " << type;
+   out << ':' << hs.HashValue();
+   if (hs.usable() == false)
+      out << " [weak]";
+   out << std::endl;
+}
 void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
 {
    if (QueueCounter <= 1)
@@ -693,33 +792,46 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
    }
 
    string const FailReason = LookupTag(Message, "FailReason");
-   enum { MAXIMUM_SIZE_EXCEEDED, HASHSUM_MISMATCH, 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 MAXIMUM_SIZE_EXCEEDED:
-           case OTHER:
-              out << LookupTag(Message, "Message") << std::endl;
-              break;
-        }
         auto const ExpectedHashes = GetExpectedHashes();
         if (ExpectedHashes.empty() == false)
         {
            out << "Hashes of expected file:" << std::endl;
            for (auto const &hs: ExpectedHashes)
-              out << " - " << hs.toStr() << std::endl;
+              formatHashsum(out, hs);
         }
         if (failreason == HASHSUM_MISMATCH)
         {
@@ -729,20 +841,22 @@ void pkgAcquire::Item::Failed(string const &Message,pkgAcquire::MethodConfig con
               std::string const tagname = std::string(*type) + "-Hash";
               std::string const hashsum = LookupTag(Message, tagname.c_str());
               if (hashsum.empty() == false)
-                 out << " - " << HashString(*type, hashsum).toStr() << std::endl;
+                 formatHashsum(out, HashString(*type, hashsum));
            }
-           out << "Last modification reported: " << LookupTag(Message, "Last-Modified", "<none>") << std::endl;
         }
-        ErrorText = out.str();
+        auto const lastmod = LookupTag(Message, "Last-Modified", "");
+        if (lastmod.empty() == false)
+           out << "Last modification reported: " << lastmod << std::endl;
       }
-      else
-        ErrorText = LookupTag(Message,"Message");
+      ErrorText = out.str();
    }
 
    switch (failreason)
    {
       case MAXIMUM_SIZE_EXCEEDED: RenameOnError(MaximumSizeExceeded); break;
       case HASHSUM_MISMATCH: RenameOnError(HashSumMismatch); break;
+      case WEAK_HASHSUMS: break;
+      case REDIRECTION_LOOP: break;
       case OTHER: break;
    }
 
@@ -886,6 +1000,47 @@ std::string pkgAcquire::Item::HashSum() const                             /*{{{*/
    return hs != NULL ? hs->toStr() : "";
 }
                                                                        /*}}}*/
+bool pkgAcquire::Item::IsRedirectionLoop(std::string const &NewURI)    /*{{{*/
+{
+   // store can fail due to permission errors and the item will "loop" then
+   if (APT::String::Startswith(NewURI, "store:"))
+      return false;
+   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;
+}
+                                                                       /*}}}*/
+int pkgAcquire::Item::Priority()                                       /*{{{*/
+{
+   // Stage 1: Meta indices and diff indices
+   // - those need to be fetched first to have progress reporting working
+   //   for the rest
+   if (dynamic_cast<pkgAcqMetaSig*>(this) != nullptr
+       || dynamic_cast<pkgAcqMetaBase*>(this) != nullptr
+       || dynamic_cast<pkgAcqDiffIndex*>(this) != nullptr)
+      return 1000;
+   // Stage 2: Diff files
+   // - fetch before complete indexes so we can apply the diffs while fetching
+   //   larger files.
+   if (dynamic_cast<pkgAcqIndexDiffs*>(this) != nullptr ||
+       dynamic_cast<pkgAcqIndexMergeDiffs*>(this) != nullptr)
+      return 800;
+
+   // Stage 3: The rest - complete index files and other stuff
+   return 500;
+}
+                                                                       /*}}}*/
 
 pkgAcqTransactionItem::pkgAcqTransactionItem(pkgAcquire * const Owner, /*{{{*/
       pkgAcqMetaClearSig * const transactionManager, IndexTarget const &target) :
@@ -956,7 +1111,7 @@ void pkgAcqMetaBase::AbortTransaction()
    {
       case TransactionStarted: break;
       case TransactionAbort: _error->Fatal("Transaction %s was already aborted and is aborted again", TransactionManager->Target.URI.c_str()); return;
-      case TransactionCommit: _error->Fatal("Transaction %s was already aborted and is now commited", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already aborted and is now committed", TransactionManager->Target.URI.c_str()); return;
    }
    TransactionManager->State = TransactionAbort;
 
@@ -998,8 +1153,8 @@ void pkgAcqMetaBase::CommitTransaction()
    switch (TransactionManager->State)
    {
       case TransactionStarted: break;
-      case TransactionAbort: _error->Fatal("Transaction %s was already commited and is now aborted", TransactionManager->Target.URI.c_str()); return;
-      case TransactionCommit: _error->Fatal("Transaction %s was already commited and is again commited", TransactionManager->Target.URI.c_str()); return;
+      case TransactionAbort: _error->Fatal("Transaction %s was already committed and is now aborted", TransactionManager->Target.URI.c_str()); return;
+      case TransactionCommit: _error->Fatal("Transaction %s was already committed and is again committed", TransactionManager->Target.URI.c_str()); return;
    }
    TransactionManager->State = TransactionCommit;
 
@@ -1077,7 +1232,7 @@ string pkgAcqMetaBase::Custom600Headers() const
    string const FinalFile = GetFinalFilename();
    struct stat Buf;
    if (stat(FinalFile.c_str(),&Buf) == 0)
-      Header += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
+      Header += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime, false);
 
    return Header;
 }
@@ -1102,9 +1257,15 @@ bool pkgAcqMetaBase::CheckDownloadDone(pkgAcqTransactionItem * const I, const st
    if (I->UsedMirror.empty() == false && _config->FindB("Acquire::SameMirrorForAllIndexes", true))
    {
       if (APT::String::Endswith(I->Desc.URI, "InRelease"))
+      {
         TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - strlen("InRelease"));
+        TransactionManager->UsedMirror = I->UsedMirror;
+      }
       else if (APT::String::Endswith(I->Desc.URI, "Release"))
+      {
         TransactionManager->BaseURI = I->Desc.URI.substr(0, I->Desc.URI.length() - strlen("Release"));
+        TransactionManager->UsedMirror = I->UsedMirror;
+      }
    }
 
    std::string const FileName = LookupTag(Message,"Filename");
@@ -1149,6 +1310,8 @@ bool pkgAcqMetaBase::CheckAuthDone(string const &Message)         /*{{{*/
    // valid signature from a key in the trusted keyring.  We
    // perform additional verification of its contents, and use them
    // to verify the indexes we are about to download
+   if (_config->FindB("Debug::pkgAcquire::Auth", false))
+      std::cerr << "Signature verification succeeded: " << DestFile << std::endl;
 
    if (TransactionManager->IMSHit == false)
    {
@@ -1169,7 +1332,8 @@ bool pkgAcqMetaBase::CheckAuthDone(string const &Message)         /*{{{*/
       LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
    }
 
-   if (TransactionManager->MetaIndexParser->Load(DestFile, &ErrorText) == false)
+   bool const GoodAuth = TransactionManager->MetaIndexParser->Load(DestFile, &ErrorText);
+   if (GoodAuth == false && AllowInsecureRepositories(InsecureType::WEAK, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == false)
    {
       Status = StatAuthError;
       return false;
@@ -1181,14 +1345,10 @@ bool pkgAcqMetaBase::CheckAuthDone(string const &Message)               /*{{{*/
       return false;
    }
 
-   if (_config->FindB("Debug::pkgAcquire::Auth", false))
-      std::cerr << "Signature verification succeeded: "
-                << DestFile << std::endl;
-
    // Download further indexes with verification
-   TransactionManager->QueueIndexes(true);
+   TransactionManager->QueueIndexes(GoodAuth);
 
-   return true;
+   return GoodAuth;
 }
                                                                        /*}}}*/
 void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                       /*{{{*/
@@ -1196,19 +1356,50 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                        /*{{{*/
    // at this point the real Items are loaded in the fetcher
    ExpectedAdditionalItems = 0;
 
-   bool const metaBaseSupportsByHash = TransactionManager->MetaIndexParser->GetSupportsAcquireByHash();
-   for (auto Target : TransactionManager->MetaIndexParser->GetIndexTargets())
-   {
+   std::set<std::string> targetsSeen;
+   bool const hasReleaseFile = TransactionManager->MetaIndexParser != NULL;
+   bool const metaBaseSupportsByHash = hasReleaseFile && TransactionManager->MetaIndexParser->GetSupportsAcquireByHash();
+   bool hasHashes = true;
+   auto IndexTargets = TransactionManager->MetaIndexParser->GetIndexTargets();
+   if (hasReleaseFile && verify == false)
+      hasHashes = std::any_of(IndexTargets.begin(), IndexTargets.end(),
+           [&](IndexTarget const &Target) { return TransactionManager->MetaIndexParser->Exists(Target.MetaKey); });
+   if (_config->FindB("Acquire::IndexTargets::Randomized", true) && likely(IndexTargets.empty() == false))
+   {
+      /* For fallback handling and to have some reasonable progress information
+        we can't randomize everything, but at least the order in the same type
+        can be as we shouldn't be telling the mirrors (and everyone else watching)
+        which is native/foreign arch, specific order of preference of translations, … */
+      auto range_start = IndexTargets.begin();
+      std::random_device rd;
+      std::default_random_engine g(rd());
+      do {
+        auto const type = range_start->Option(IndexTarget::CREATED_BY);
+        auto const range_end = std::find_if_not(range_start, IndexTargets.end(),
+              [&type](IndexTarget const &T) { return type == T.Option(IndexTarget::CREATED_BY); });
+        std::shuffle(range_start, range_end, g);
+        range_start = range_end;
+      } while (range_start != IndexTargets.end());
+   }
+   for (auto&& Target: IndexTargets)
+   {
+      // if we have seen a target which is created-by a target this one here is declared a
+      // fallback to, we skip acquiring the fallback (but we make sure we clean up)
+      if (targetsSeen.find(Target.Option(IndexTarget::FALLBACK_OF)) != targetsSeen.end())
+      {
+        targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
+        new CleanupItem(Owner, TransactionManager, Target);
+        continue;
+      }
       // all is an implementation detail. Users shouldn't use this as arch
       // We need this support trickery here as e.g. Debian has binary-all files already,
       // but arch:all packages are still in the arch:any files, so we would waste precious
       // download time, bandwidth and diskspace for nothing, BUT Debian doesn't feature all
       // in the set of supported architectures, so we can filter based on this property rather
       // than invent an entirely new flag we would need to carry for all of eternity.
-      if (Target.Option(IndexTarget::ARCHITECTURE) == "all")
+      if (hasReleaseFile && Target.Option(IndexTarget::ARCHITECTURE) == "all")
       {
-        if (TransactionManager->MetaIndexParser->IsArchitectureSupported("all") == false ||
-              TransactionManager->MetaIndexParser->IsArchitectureAllSupportedFor(Target) == false)
+        if (TransactionManager->MetaIndexParser->IsArchitectureAllSupportedFor(Target) == false)
         {
            new CleanupItem(Owner, TransactionManager, Target);
            continue;
@@ -1216,12 +1407,12 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                        /*{{{*/
       }
 
       bool trypdiff = Target.OptionBool(IndexTarget::PDIFFS);
-      if (verify == true)
+      if (hasReleaseFile == true)
       {
         if (TransactionManager->MetaIndexParser->Exists(Target.MetaKey) == false)
         {
            // optional targets that we do not have in the Release file are skipped
-           if (Target.IsOptional)
+           if (hasHashes == true && Target.IsOptional)
            {
               new CleanupItem(Owner, TransactionManager, Target);
               continue;
@@ -1240,23 +1431,31 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                        /*{{{*/
               // if the architecture is officially supported but currently no packages for it available,
               // ignore silently as this is pretty much the same as just shipping an empty file.
               // if we don't know which architectures are supported, we do NOT ignore it to notify user about this
-              if (TransactionManager->MetaIndexParser->IsArchitectureSupported("*undefined*") == false)
+              if (hasHashes == true && TransactionManager->MetaIndexParser->IsArchitectureSupported("*undefined*") == false)
               {
                  new CleanupItem(Owner, TransactionManager, Target);
                  continue;
               }
            }
 
-           Status = StatAuthError;
-           strprintf(ErrorText, _("Unable to find expected entry '%s' in Release file (Wrong sources.list entry or malformed file)"), Target.MetaKey.c_str());
-           return;
+           if (hasHashes == true)
+           {
+              Status = StatAuthError;
+              strprintf(ErrorText, _("Unable to find expected entry '%s' in Release file (Wrong sources.list entry or malformed file)"), Target.MetaKey.c_str());
+              return;
+           }
+           else
+           {
+              new pkgAcqIndex(Owner, TransactionManager, Target);
+              continue;
+           }
         }
-        else
+        else if (verify)
         {
            auto const hashes = GetExpectedHashesFor(Target.MetaKey);
            if (hashes.empty() == false)
            {
-              if (hashes.usable() == false)
+              if (hashes.usable() == false && TargetIsAllowedToBe(TransactionManager->Target, InsecureType::WEAK) == false)
               {
                  new CleanupItem(Owner, TransactionManager, Target);
                  _error->Warning(_("Skipping acquire of configured file '%s' as repository '%s' provides only weak security information for it"),
@@ -1267,6 +1466,7 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                  /*{{{*/
               else if (hashes.FileSize() == 0)
               {
                  new CleanupItem(Owner, TransactionManager, Target);
+                 targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
                  continue;
               }
            }
@@ -1327,6 +1527,7 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                  /*{{{*/
            std::string const idxfilename = GetFinalFileNameFromURI(GetDiffIndexURI(Target));
            if (FileExists(idxfilename))
               new NoActionItem(Owner, Target, idxfilename);
+           targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
            continue;
         }
 
@@ -1348,6 +1549,7 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                  /*{{{*/
       }
 
       // Queue the Index file (Packages, Sources, Translation-$foo, …)
+      targetsSeen.emplace(Target.Option(IndexTarget::CREATED_BY));
       if (trypdiff)
          new pkgAcqDiffIndex(Owner, TransactionManager, Target);
       else
@@ -1357,24 +1559,6 @@ void pkgAcqMetaClearSig::QueueIndexes(bool const verify)                 /*{{{*/
                                                                        /*}}}*/
 bool pkgAcqMetaBase::VerifyVendor(string const &)                      /*{{{*/
 {
-   string Transformed = TransactionManager->MetaIndexParser->GetExpectedDist();
-
-   if (Transformed == "../project/experimental")
-   {
-      Transformed = "experimental";
-   }
-
-   auto pos = Transformed.rfind('/');
-   if (pos != string::npos)
-   {
-      Transformed = Transformed.substr(0, pos);
-   }
-
-   if (Transformed == ".")
-   {
-      Transformed = "";
-   }
-
    if (TransactionManager->MetaIndexParser->GetValidUntil() > 0)
    {
       time_t const invalid_since = time(NULL) - TransactionManager->MetaIndexParser->GetValidUntil();
@@ -1409,30 +1593,27 @@ bool pkgAcqMetaBase::VerifyVendor(string const &)                       /*{{{*/
       TransactionManager->LastMetaIndexParser = NULL;
    }
 
-   if (_config->FindB("Debug::pkgAcquire::Auth", false)) 
+   if (_config->FindB("Debug::pkgAcquire::Auth", false))
    {
       std::cerr << "Got Codename: " << TransactionManager->MetaIndexParser->GetCodename() << std::endl;
+      std::cerr << "Got Suite: " << TransactionManager->MetaIndexParser->GetSuite() << std::endl;
       std::cerr << "Expecting Dist: " << TransactionManager->MetaIndexParser->GetExpectedDist() << std::endl;
-      std::cerr << "Transformed Dist: " << Transformed << std::endl;
    }
 
-   if (TransactionManager->MetaIndexParser->CheckDist(Transformed) == false)
+   // One day that might become fatal…
+   auto const ExpectedDist = TransactionManager->MetaIndexParser->GetExpectedDist();
+   auto const NowCodename = TransactionManager->MetaIndexParser->GetCodename();
+   if (TransactionManager->MetaIndexParser->CheckDist(ExpectedDist) == false)
+      _error->Warning(_("Conflicting distribution: %s (expected %s but got %s)"),
+           Desc.Description.c_str(), ExpectedDist.c_str(), NowCodename.c_str());
+   // might be okay, might be not
+   if (TransactionManager->LastMetaIndexParser != nullptr)
    {
-      // This might become fatal one day
-//       Status = StatAuthError;
-//       ErrorText = "Conflicting distribution; expected "
-//          + MetaIndexParser->GetExpectedDist() + " but got "
-//          + MetaIndexParser->GetCodename();
-//       return false;
-      if (!Transformed.empty())
-      {
-         _error->Warning(_("Conflicting distribution: %s (expected %s but got %s)"),
-                         Desc.Description.c_str(),
-                         Transformed.c_str(),
-                         TransactionManager->MetaIndexParser->GetCodename().c_str());
-      }
+      auto const LastCodename = TransactionManager->LastMetaIndexParser->GetCodename();
+      if (LastCodename.empty() == false && NowCodename.empty() == false && LastCodename != NowCodename)
+        _error->Warning(_("Conflicting distribution: %s (expected %s but got %s)"),
+              Desc.Description.c_str(), LastCodename.c_str(), NowCodename.c_str());
    }
-
    return true;
 }
                                                                        /*}}}*/
@@ -1445,8 +1626,7 @@ pkgAcqMetaClearSig::pkgAcqMetaClearSig(pkgAcquire * const Owner,  /*{{{*/
       IndexTarget const &DetachedDataTarget, IndexTarget const &DetachedSigTarget,
       metaIndex * const MetaIndexParser) :
    pkgAcqMetaIndex(Owner, this, ClearsignedTarget, DetachedSigTarget),
-   d(NULL), ClearsignedTarget(ClearsignedTarget),
-   DetachedDataTarget(DetachedDataTarget),
+   d(NULL), DetachedDataTarget(DetachedDataTarget),
    MetaIndexParser(MetaIndexParser), LastMetaIndexParser(NULL)
 {
    // index targets + (worst case:) Release/Release.gpg
@@ -1518,6 +1698,17 @@ void pkgAcqMetaClearSig::Done(std::string const &Message,
         new NoActionItem(Owner, DetachedSigTarget);
       }
    }
+   else if (Status != StatAuthError)
+   {
+      string const FinalFile = GetFinalFileNameFromURI(DetachedDataTarget.URI);
+      string const OldFile = GetFinalFilename();
+      if (TransactionManager->IMSHit == false)
+        TransactionManager->TransactionStageCopy(this, DestFile, FinalFile);
+      else if (RealFileExists(OldFile) == false)
+        new NoActionItem(Owner, DetachedDataTarget);
+      else
+        TransactionManager->TransactionStageCopy(this, OldFile, FinalFile);
+   }
 }
                                                                        /*}}}*/
 void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf) /*{{{*/
@@ -1549,10 +1740,7 @@ void pkgAcqMetaClearSig::Failed(string const &Message,pkgAcquire::MethodConfig c
       if(CheckStopAuthentication(this, Message))
          return;
 
-      // No Release file was present, or verification failed, so fall
-      // back to queueing Packages files without verification
-      // only allow going further if the user explicitly wants it
-      if(AllowInsecureRepositories(_("The repository '%s' is not signed."), ClearsignedTarget.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+      if(AllowInsecureRepositories(InsecureType::UNSIGNED, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
       {
         Status = StatDone;
 
@@ -1623,7 +1811,7 @@ void pkgAcqMetaIndex::Failed(string const &Message,
    // No Release file was present so fall
    // back to queueing Packages files without verification
    // only allow going further if the user explicitly wants it
-   if(AllowInsecureRepositories(_("The repository '%s' does not have a Release file."), Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+   if(AllowInsecureRepositories(InsecureType::NORELEASE, Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
    {
       // ensure old Release files are removed
       TransactionManager->TransactionStageRemoval(this, GetFinalFilename());
@@ -1717,12 +1905,26 @@ void pkgAcqMetaSig::Done(string const &Message, HashStringList const &Hashes,
    }
    else if(MetaIndex->CheckAuthDone(Message) == true)
    {
-      if (TransactionManager->IMSHit == false)
+      auto const Releasegpg = GetFinalFilename();
+      auto const Release = MetaIndex->GetFinalFilename();
+      // if this is an IMS-Hit on Release ensure we also have the the Release.gpg file stored
+      // (previously an unknown pubkey) – but only if the Release file exists locally (unlikely
+      // event of InRelease removed from the mirror causing fallback but still an IMS-Hit)
+      if (TransactionManager->IMSHit == false ||
+           (FileExists(Releasegpg) == false && FileExists(Release) == true))
       {
-        TransactionManager->TransactionStageCopy(this, DestFile, GetFinalFilename());
-        TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, MetaIndex->GetFinalFilename());
+        TransactionManager->TransactionStageCopy(this, DestFile, Releasegpg);
+        TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, Release);
       }
    }
+   else if (MetaIndex->Status != StatAuthError)
+   {
+      std::string const FinalFile = MetaIndex->GetFinalFilename();
+      if (TransactionManager->IMSHit == false)
+        TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, FinalFile);
+      else
+        TransactionManager->TransactionStageCopy(MetaIndex, FinalFile, FinalFile);
+   }
 }
                                                                        /*}}}*/
 void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
@@ -1733,40 +1935,14 @@ void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const
    if (MetaIndex->AuthPass == true && MetaIndex->CheckStopAuthentication(this, Message))
          return;
 
-   string const FinalRelease = MetaIndex->GetFinalFilename();
-   string const FinalReleasegpg = GetFinalFilename();
-   string const FinalInRelease = TransactionManager->GetFinalFilename();
-
-   if (RealFileExists(FinalReleasegpg) || RealFileExists(FinalInRelease))
-   {
-      std::string downgrade_msg;
-      strprintf(downgrade_msg, _("The repository '%s' is no longer signed."),
-                MetaIndex->Target.Description.c_str());
-      if(_config->FindB("Acquire::AllowDowngradeToInsecureRepositories"))
-      {
-         // meh, the users wants to take risks (we still mark the packages
-         // from this repository as unauthenticated)
-         _error->Warning("%s", downgrade_msg.c_str());
-         _error->Warning(_("This is normally not allowed, but the option "
-                           "Acquire::AllowDowngradeToInsecureRepositories was "
-                           "given to override it."));
-         Status = StatDone;
-      } else {
-        MessageInsecureRepository(true, downgrade_msg);
-        if (TransactionManager->IMSHit == false)
-           Rename(MetaIndex->DestFile, MetaIndex->DestFile + ".FAILED");
-        Item::Failed("Message: " + downgrade_msg, Cnf);
-         TransactionManager->AbortTransaction();
-         return;
-      }
-   }
-
    // ensures that a Release.gpg file in the lists/ is removed by the transaction
    TransactionManager->TransactionStageRemoval(this, DestFile);
 
    // only allow going further if the user explicitly wants it
-   if (AllowInsecureRepositories(_("The repository '%s' is not signed."), MetaIndex->Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
+   if (AllowInsecureRepositories(InsecureType::UNSIGNED, MetaIndex->Target.Description, TransactionManager->MetaIndexParser, TransactionManager, this) == true)
    {
+      string const FinalRelease = MetaIndex->GetFinalFilename();
+      string const FinalInRelease = TransactionManager->GetFinalFilename();
       LoadLastMetaIndexParser(TransactionManager, FinalRelease, FinalInRelease);
 
       // we parse the indexes here because at this point the user wanted
@@ -1777,8 +1953,10 @@ void pkgAcqMetaSig::Failed(string const &Message,pkgAcquire::MethodConfig const
       else
         TransactionManager->QueueIndexes(GoodLoad);
 
-      TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, MetaIndex->GetFinalFilename());
+      TransactionManager->TransactionStageCopy(MetaIndex, MetaIndex->DestFile, FinalRelease);
    }
+   else if (TransactionManager->IMSHit == false)
+      Rename(MetaIndex->DestFile, MetaIndex->DestFile + ".FAILED");
 
    // FIXME: this is used often (e.g. in pkgAcqIndexTrans) so refactor
    if (Cnf->LocalOnly == true ||
@@ -1810,7 +1988,7 @@ void pkgAcqBaseIndex::Failed(std::string const &Message,pkgAcquire::MethodConfig
    if (timespec == 0)
       ErrorText.append("<unknown>");
    else
-      ErrorText.append(TimeRFC1123(timespec));
+      ErrorText.append(TimeRFC1123(timespec, true));
    ErrorText.append("\n");
 }
                                                                        /*}}}*/
@@ -1826,51 +2004,52 @@ pkgAcqBaseIndex::~pkgAcqBaseIndex() {}
 pkgAcqDiffIndex::pkgAcqDiffIndex(pkgAcquire * const Owner,
                                  pkgAcqMetaClearSig * const TransactionManager,
                                  IndexTarget const &Target)
-   : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL), diffs(NULL)
+   : pkgAcqIndex(Owner, TransactionManager, Target, true), d(NULL), diffs(NULL)
 {
    // FIXME: Magic number as an upper bound on pdiffs we will reasonably acquire
    ExpectedAdditionalItems = 40;
-
    Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
 
-   Desc.Owner = this;
-   Desc.Description = GetDiffIndexFileName(Target.Description);
-   Desc.ShortDesc = Target.ShortDesc;
-   Desc.URI = GetDiffIndexURI(Target);
-
-   DestFile = GetPartialFileNameFromURI(Desc.URI);
+   CompressionExtensions.clear();
+   {
+      std::vector<std::string> types = APT::Configuration::getCompressionTypes();
+      if (types.empty() == false)
+      {
+        std::ostringstream os;
+        std::copy_if(types.begin(), types.end()-1, std::ostream_iterator<std::string>(os, " "), [&](std::string const type) {
+              if (type == "uncompressed")
+                 return true;
+              return TransactionManager->MetaIndexParser->Exists(GetDiffIndexFileName(Target.MetaKey) + '.' + type);
+        });
+        os << *types.rbegin();
+        CompressionExtensions = os.str();
+      }
+   }
+   if (Target.Option(IndexTarget::COMPRESSIONTYPES).find("by-hash") != std::string::npos)
+      CompressionExtensions = "by-hash " + CompressionExtensions;
+   Init(GetDiffIndexURI(Target), GetDiffIndexFileName(Target.Description), Target.ShortDesc);
 
    if(Debug)
       std::clog << "pkgAcqDiffIndex: " << Desc.URI << std::endl;
-
-   QueueURI(Desc);
-}
-                                                                       /*}}}*/
-// AcqIndex::Custom600Headers - Insert custom request headers          /*{{{*/
-// ---------------------------------------------------------------------
-/* The only header we use is the last-modified header. */
-string pkgAcqDiffIndex::Custom600Headers() const
-{
-   if (TransactionManager->LastMetaIndexParser != NULL)
-      return "\nIndex-File: true";
-
-   string const Final = GetFinalFilename();
-
-   if(Debug)
-      std::clog << "Custom600Header-IMS: " << Final << std::endl;
-
-   struct stat Buf;
-   if (stat(Final.c_str(),&Buf) != 0)
-      return "\nIndex-File: true";
-   
-   return "\nIndex-File: true\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
 }
                                                                        /*}}}*/
 void pkgAcqDiffIndex::QueueOnIMSHit() const                            /*{{{*/
 {
    // list cleanup needs to know that this file as well as the already
    // present index is ours, so we create an empty diff to save it for us
-   new pkgAcqIndexDiffs(Owner, TransactionManager, Target);
+   new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, Target.URI);
+}
+                                                                       /*}}}*/
+static bool RemoveFileForBootstrapLinking(bool const Debug, std::string const &For, std::string const &Boot)/*{{{*/
+{
+   if (FileExists(Boot) && RemoveFile("Bootstrap-linking", Boot) == false)
+   {
+      if (Debug)
+        std::clog << "Bootstrap-linking for patching " << For
+           << " by removing stale " << Boot << " failed!" << std::endl;
+      return false;
+   }
+   return true;
 }
                                                                        /*}}}*/
 bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)      /*{{{*/
@@ -1882,7 +2061,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       std::clog << "pkgAcqDiffIndex::ParseIndexDiff() " << IndexDiffFile
         << std::endl;
 
-   FileFd Fd(IndexDiffFile,FileFd::ReadOnly);
+   FileFd Fd(IndexDiffFile, FileFd::ReadOnly, FileFd::Extension);
    pkgTagFile TF(&Fd);
    if (Fd.IsOpen() == false || Fd.Failed())
       return false;
@@ -1894,6 +2073,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
    HashStringList ServerHashes;
    unsigned long long ServerSize = 0;
 
+   auto const &posix = std::locale::classic();
    for (char const * const * type = HashString::SupportedHashes(); *type != NULL; ++type)
    {
       std::string tagname = *type;
@@ -1905,6 +2085,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       string hash;
       unsigned long long size;
       std::stringstream ss(tmp);
+      ss.imbue(posix);
       ss >> hash >> size;
       if (unlikely(hash.empty() == true))
         continue;
@@ -1983,6 +2164,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       string hash, filename;
       unsigned long long size;
       std::stringstream ss(tmp);
+      ss.imbue(posix);
 
       while (ss >> hash >> size >> filename)
       {
@@ -2041,6 +2223,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       string hash, filename;
       unsigned long long size;
       std::stringstream ss(tmp);
+      ss.imbue(posix);
 
       while (ss >> hash >> size >> filename)
       {
@@ -2078,6 +2261,7 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
       string hash, filename;
       unsigned long long size;
       std::stringstream ss(tmp);
+      ss.imbue(posix);
 
       // FIXME: all of pdiff supports only .gz compressed patches
       while (ss >> hash >> size >> filename)
@@ -2208,23 +2392,15 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)       /*{{{*/
       if (unlikely(Final.empty())) // because we wouldn't be called in such a case
         return false;
       std::string const PartialFile = GetPartialFileNameFromURI(Target.URI);
-      if (FileExists(PartialFile) && RemoveFile("Bootstrap-linking", PartialFile) == false)
-      {
-        if (Debug)
-           std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile
-              << " by removing stale " << PartialFile << " failed!" << std::endl;
+      std::string const PatchedFile = GetKeepCompressedFileName(PartialFile + "-patched", Target);
+      if (RemoveFileForBootstrapLinking(Debug, CurrentPackagesFile, PartialFile) == false ||
+           RemoveFileForBootstrapLinking(Debug, CurrentPackagesFile, PatchedFile) == false)
         return false;
-      }
       for (auto const &ext : APT::Configuration::getCompressorExtensions())
       {
-        std::string const Partial = PartialFile + ext;
-        if (FileExists(Partial) && RemoveFile("Bootstrap-linking", Partial) == false)
-        {
-           if (Debug)
-              std::clog << "Bootstrap-linking for patching " << CurrentPackagesFile
-                 << " by removing stale " << Partial << " failed!" << std::endl;
+        if (RemoveFileForBootstrapLinking(Debug, CurrentPackagesFile, PartialFile + ext) == false ||
+              RemoveFileForBootstrapLinking(Debug, CurrentPackagesFile, PatchedFile + ext) == false)
            return false;
-        }
       }
       std::string const Ext = Final.substr(CurrentPackagesFile.length());
       std::string const Partial = PartialFile + Ext;
@@ -2237,14 +2413,26 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile)       /*{{{*/
       }
    }
 
+   std::string indexURI = Desc.URI;
+   auto const byhashidx = indexURI.find("/by-hash/");
+   if (byhashidx != std::string::npos)
+      indexURI = indexURI.substr(0, byhashidx - strlen(".diff"));
+   else
+   {
+      auto end = indexURI.length() - strlen(".diff/Index");
+      if (CurrentCompressionExtension != "uncompressed")
+        end -= (1 + CurrentCompressionExtension.length());
+      indexURI = indexURI.substr(0, end);
+   }
+
    if (pdiff_merge == false)
-      new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+      new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, indexURI, available_patches);
    else
    {
       diffs = new std::vector<pkgAcqIndexMergeDiffs*>(available_patches.size());
       for(size_t i = 0; i < available_patches.size(); ++i)
         (*diffs)[i] = new pkgAcqIndexMergeDiffs(Owner, TransactionManager,
-               Target,
+               Target, UsedMirror, indexURI,
               available_patches[i],
               diffs);
    }
@@ -2257,7 +2445,9 @@ bool pkgAcqDiffIndex::ParseDiffIndex(string const &IndexDiffFile) /*{{{*/
                                                                        /*}}}*/
 void pkgAcqDiffIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)/*{{{*/
 {
-   pkgAcqBaseIndex::Failed(Message,Cnf);
+   if (CommonFailed(GetDiffIndexURI(Target), GetDiffIndexFileName(Target.Description), Message, Cnf))
+      return;
+
    Status = StatDone;
    ExpectedAdditionalItems = 0;
 
@@ -2312,8 +2502,9 @@ pkgAcqDiffIndex::~pkgAcqDiffIndex()
 pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire * const Owner,
                                    pkgAcqMetaClearSig * const TransactionManager,
                                    IndexTarget const &Target,
+                                  std::string const &indexUsedMirror, std::string const &indexURI,
                                   vector<DiffInfo> const &diffs)
-   : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL),
+   : pkgAcqBaseIndex(Owner, TransactionManager, Target), indexURI(indexURI),
      available_patches(diffs)
 {
    DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI), Target);
@@ -2324,6 +2515,12 @@ pkgAcqIndexDiffs::pkgAcqIndexDiffs(pkgAcquire * const Owner,
    Description = Target.Description;
    Desc.ShortDesc = Target.ShortDesc;
 
+   UsedMirror = indexUsedMirror;
+   if (UsedMirror == "DIRECT")
+      UsedMirror.clear();
+   else if (UsedMirror.empty() == false && Description.find(" ") != string::npos)
+      Description.replace(0, Description.find(" "), UsedMirror);
+
    if(available_patches.empty() == true)
    {
       // we are done (yeah!), check hashes against the final file
@@ -2438,7 +2635,7 @@ bool pkgAcqIndexDiffs::QueueNextDiff()                                    /*{{{*/
    }
 
    // queue the right diff
-   Desc.URI = Target.URI + ".diff/" + available_patches[0].file + ".gz";
+   Desc.URI = indexURI + ".diff/" + available_patches[0].file + ".gz";
    Desc.Description = Description + " " + available_patches[0].file + string(".pdiff");
    DestFile = GetKeepCompressedFileName(GetPartialFileNameFromURI(Target.URI + ".diff/" + available_patches[0].file), Target);
 
@@ -2491,7 +2688,7 @@ void pkgAcqIndexDiffs::Done(string const &Message, HashStringList const &Hashes,
         // see if there is more to download
         if(available_patches.empty() == false)
         {
-           new pkgAcqIndexDiffs(Owner, TransactionManager, Target, available_patches);
+           new pkgAcqIndexDiffs(Owner, TransactionManager, Target, UsedMirror, indexURI, available_patches);
            Finish();
         } else {
            DestFile = PatchedFile;
@@ -2506,9 +2703,10 @@ std::string pkgAcqIndexDiffs::Custom600Headers() const                   /*{{{*/
    if(State != StateApplyDiff)
       return pkgAcqBaseIndex::Custom600Headers();
    std::ostringstream patchhashes;
-   HashStringList const ExpectedHashes = available_patches[0].patch_hashes;
-   for (HashStringList::const_iterator hs = ExpectedHashes.begin(); hs != ExpectedHashes.end(); ++hs)
-      patchhashes <<  "\nPatch-0-" << hs->HashType() << "-Hash: " << hs->HashValue();
+   for (auto && hs : available_patches[0].result_hashes)
+      patchhashes <<  "\nStart-" << hs.HashType() << "-Hash: " << hs.HashValue();
+   for (auto && hs : available_patches[0].patch_hashes)
+      patchhashes <<  "\nPatch-0-" << hs.HashType() << "-Hash: " << hs.HashValue();
    patchhashes << pkgAcqBaseIndex::Custom600Headers();
    return patchhashes.str();
 }
@@ -2519,19 +2717,26 @@ pkgAcqIndexDiffs::~pkgAcqIndexDiffs() {}
 pkgAcqIndexMergeDiffs::pkgAcqIndexMergeDiffs(pkgAcquire * const Owner,
                                              pkgAcqMetaClearSig * const TransactionManager,
                                              IndexTarget const &Target,
+                                            std::string const &indexUsedMirror, std::string const &indexURI,
                                              DiffInfo const &patch,
                                              std::vector<pkgAcqIndexMergeDiffs*> const * const allPatches)
-  : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL),
-     patch(patch), allPatches(allPatches), State(StateFetchDiff)
+  : pkgAcqBaseIndex(Owner, TransactionManager, Target), indexURI(indexURI),
+    patch(patch), allPatches(allPatches), State(StateFetchDiff)
 {
    Debug = _config->FindB("Debug::pkgAcquire::Diffs",false);
 
-   Desc.Owner = this;
    Description = Target.Description;
+   UsedMirror = indexUsedMirror;
+   if (UsedMirror == "DIRECT")
+      UsedMirror.clear();
+   else if (UsedMirror.empty() == false && Description.find(" ") != string::npos)
+      Description.replace(0, Description.find(" "), UsedMirror);
+
+   Desc.Owner = this;
    Desc.ShortDesc = Target.ShortDesc;
-   Desc.URI = Target.URI + ".diff/" + patch.file + ".gz";
+   Desc.URI = indexURI + ".diff/" + patch.file + ".gz";
    Desc.Description = Description + " " + patch.file + ".pdiff";
-   DestFile = GetPartialFileNameFromURI(Desc.URI);
+   DestFile = GetPartialFileNameFromURI(Target.URI + ".diff/" + patch.file + ".gz");
 
    if(Debug)
       std::clog << "pkgAcqIndexMergeDiffs: " << Desc.URI << std::endl;
@@ -2655,12 +2860,14 @@ std::string pkgAcqIndexMergeDiffs::Custom600Headers() const             /*{{{*/
       return pkgAcqBaseIndex::Custom600Headers();
    std::ostringstream patchhashes;
    unsigned int seen_patches = 0;
+   for (auto && hs : (*allPatches)[0]->patch.result_hashes)
+      patchhashes <<  "\nStart-" << hs.HashType() << "-Hash: " << hs.HashValue();
    for (std::vector<pkgAcqIndexMergeDiffs *>::const_iterator I = allPatches->begin();
         I != allPatches->end(); ++I)
    {
       HashStringList const ExpectedHashes = (*I)->patch.patch_hashes;
       for (HashStringList::const_iterator hs = ExpectedHashes.begin(); hs != ExpectedHashes.end(); ++hs)
-        patchhashes <<  "\nPatch-" << seen_patches << "-" << hs->HashType() << "-Hash: " << hs->HashValue();
+        patchhashes <<  "\nPatch-" << std::to_string(seen_patches) << "-" << hs->HashType() << "-Hash: " << hs->HashValue();
       ++seen_patches;
    }
    patchhashes << pkgAcqBaseIndex::Custom600Headers();
@@ -2672,10 +2879,12 @@ pkgAcqIndexMergeDiffs::~pkgAcqIndexMergeDiffs() {}
 // AcqIndex::AcqIndex - Constructor                                    /*{{{*/
 pkgAcqIndex::pkgAcqIndex(pkgAcquire * const Owner,
                          pkgAcqMetaClearSig * const TransactionManager,
-                         IndexTarget const &Target)
+                         IndexTarget const &Target, bool const Derived)
    : pkgAcqBaseIndex(Owner, TransactionManager, Target), d(NULL), Stage(STAGE_DOWNLOAD),
    CompressionExtensions(Target.Option(IndexTarget::COMPRESSIONTYPES))
 {
+   if (Derived)
+      return;
    Init(Target.URI, Target.Description, Target.ShortDesc);
 
    if(_config->FindB("Debug::Acquire::Transaction", false) == true)
@@ -2708,10 +2917,6 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
    DestFile = GetPartialFileNameFromURI(URI);
    NextCompressionExtension(CurrentCompressionExtension, CompressionExtensions, false);
 
-   // store file size of the download to ensure the fetcher gives
-   // accurate progress reporting
-   FileSize = GetExpectedHashes().FileSize();
-
    if (CurrentCompressionExtension == "uncompressed")
    {
       Desc.URI = URI;
@@ -2726,6 +2931,8 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
         Desc.URI = URI + '.' + CurrentCompressionExtension;
         DestFile = DestFile + '.' + CurrentCompressionExtension;
       }
+      else
+        Desc.URI = URI;
 
       HashStringList const Hashes = GetExpectedHashes();
       HashString const * const TargetHash = Hashes.find(NULL);
@@ -2748,6 +2955,9 @@ void pkgAcqIndex::Init(string const &URI, string const &URIDesc,
       DestFile = DestFile + '.' + CurrentCompressionExtension;
    }
 
+   // store file size of the download to ensure the fetcher gives
+   // accurate progress reporting
+   FileSize = GetExpectedHashes().FileSize();
 
    Desc.Description = URIDesc;
    Desc.Owner = this;
@@ -2770,7 +2980,7 @@ string pkgAcqIndex::Custom600Headers() const
 
       struct stat Buf;
       if (stat(Final.c_str(),&Buf) == 0)
-        msg += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime);
+        msg += "\nLast-Modified: " + TimeRFC1123(Buf.st_mtime, false);
    }
 
    if(Target.IsOptional)
@@ -2780,20 +2990,40 @@ string pkgAcqIndex::Custom600Headers() const
 }
                                                                        /*}}}*/
 // AcqIndex::Failed - getting the indexfile failed                     /*{{{*/
-void pkgAcqIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
+bool pkgAcqIndex::CommonFailed(std::string const &TargetURI, std::string const TargetDesc,
+      std::string const &Message, pkgAcquire::MethodConfig const * const Cnf)
 {
    pkgAcqBaseIndex::Failed(Message,Cnf);
 
+   if (UsedMirror.empty() == false && UsedMirror != "DIRECT" &&
+        LookupTag(Message, "FailReason") == "HttpError404")
+   {
+      UsedMirror = "DIRECT";
+      if (Desc.URI.find("/by-hash/") != std::string::npos)
+        CompressionExtensions = "by-hash " + CompressionExtensions;
+      else
+        CompressionExtensions = CurrentCompressionExtension + ' ' + CompressionExtensions;
+      Init(TargetURI, TargetDesc, Desc.ShortDesc);
+      Status = StatIdle;
+      return true;
+   }
+
    // authorisation matches will not be fixed by other compression types
    if (Status != StatAuthError)
    {
       if (CompressionExtensions.empty() == false)
       {
-        Init(Target.URI, Desc.Description, Desc.ShortDesc);
+        Init(TargetURI, Desc.Description, Desc.ShortDesc);
         Status = StatIdle;
-        return;
+        return true;
       }
    }
+   return false;
+}
+void pkgAcqIndex::Failed(string const &Message,pkgAcquire::MethodConfig const * const Cnf)
+{
+   if (CommonFailed(Target.URI, Target.Description, Message, Cnf))
+      return;
 
    if(Target.IsOptional && GetExpectedHashes().empty() && Stage == STAGE_DOWNLOAD)
       Status = StatDone;
@@ -3101,9 +3331,8 @@ bool pkgAcqArchive::QueueNext()
 
       // Create the item
       Local = false;
-      QueueURI(Desc);
-
       ++Vf;
+      QueueURI(Desc);
       return true;
    }
    return false;
@@ -3262,7 +3491,7 @@ void pkgAcqChangelog::Init(std::string const &DestDir, std::string const &DestFi
    TemporaryDirectory = tmpname;
 
    ChangeOwnerAndPermissionOfFile("Item::QueueURI", TemporaryDirectory.c_str(),
-        SandboxUser.c_str(), "root", 0700);
+        SandboxUser.c_str(), ROOT_GROUP, 0700);
 
    DestFile = flCombine(TemporaryDirectory, DestFileName);
    if (DestDir.empty() == false)
@@ -3310,7 +3539,8 @@ std::string pkgAcqChangelog::URI(pkgCache::VerIterator const &Ver)        /*{{{*/
       pkgCache::PkgIterator const Pkg = Ver.ParentPkg();
       if (Pkg->CurrentVer != 0 && Pkg.CurrentVer() == Ver)
       {
-        std::string const basename = std::string("/usr/share/doc/") + Pkg.Name() + "/changelog";
+        std::string const root = _config->FindDir("Dir");
+        std::string const basename = root + std::string("usr/share/doc/") + Pkg.Name() + "/changelog";
         std::string const debianname = basename + ".Debian";
         if (FileExists(debianname))
            return "copy://" + debianname;
@@ -3373,7 +3603,7 @@ std::string pkgAcqChangelog::URITemplate(pkgCache::RlsFileIterator const &Rls)
         should be so this could produce request order-dependent anomalies */
       if (OpenMaybeClearSignedFile(Rls.FileName(), rf) == true)
       {
-        pkgTagFile TagFile(&rf, rf.Size());
+        pkgTagFile TagFile(&rf);
         pkgTagSection Section;
         if (TagFile.Step(Section) == true)
            server = Section.FindS("Changelogs");