Adding upstream version 2.6.1.upstream/2.6.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 325 insertions, 0 deletions

diff --git a/apt-pkg/contrib/extracttar.cc b/apt-pkg/contrib/extracttar.cc
new file mode 100644
index 0000000..dc24375
--- /dev/null
+++ b/apt-pkg/contrib/extracttar.cc
@@ -0,0 +1,325 @@
+// -*- mode: cpp; mode: fold -*-
+// Description								/*{{{*/
+/* ######################################################################
+
+   Extract a Tar - Tar Extractor
+
+   Some performance measurements showed that zlib performed quite poorly
+   in comparison to a forked gzip process. This tar extractor makes use
+   of the fact that dup'd file descriptors have the same seek pointer
+   and that gzip will not read past the end of a compressed stream, 
+   even if there is more data. We use the dup property to track extraction
+   progress and the gzip feature to just feed gzip a fd in the middle
+   of an AR file. 
+   
+   ##################################################################### */
+									/*}}}*/
+// Include Files							/*{{{*/
+#include <config.h>
+
+#include <apt-pkg/configuration.h>
+#include <apt-pkg/dirstream.h>
+#include <apt-pkg/error.h>
+#include <apt-pkg/extracttar.h>
+#include <apt-pkg/fileutl.h>
+#include <apt-pkg/strutl.h>
+
+#include <algorithm>
+#include <iostream>
+#include <string>
+#include <fcntl.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <apti18n.h>
+									/*}}}*/
+
+using namespace std;
+    
+// The on disk header for a tar file.
+struct ExtractTar::TarHeader
+{
+   char Name[100];
+   char Mode[8];
+   char UserID[8];
+   char GroupID[8];
+   char Size[12];
+   char MTime[12];
+   char Checksum[8];
+   char LinkFlag;
+   char LinkName[100];
+   char MagicNumber[8];
+   char UserName[32];
+   char GroupName[32];
+   char Major[8];
+   char Minor[8];      
+};
+
+// We need to read long names (names and link targets) into memory, so let's
+// have a limit (shamelessly stolen from libarchive) to avoid people OOMing
+// us with large streams.
+static const unsigned long long APT_LONGNAME_LIMIT = 1048576llu;
+
+// A file size limit that we allow extracting. Currently, that's 128 GB.
+// We also should leave some wiggle room for code adding files to it, and
+// possibly conversion for signed, so this should not be larger than like 2**62.
+static const unsigned long long APT_FILESIZE_LIMIT = 1llu << 37;
+
+// ExtractTar::ExtractTar - Constructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::ExtractTar(FileFd &Fd,unsigned long long Max,string DecompressionProgram)
+	: File(Fd), MaxInSize(Max), DecompressProg(DecompressionProgram)
+{
+   GZPid = -1;
+   Eof = false;
+}
+									/*}}}*/
+// ExtractTar::ExtractTar - Destructor					/*{{{*/
+// ---------------------------------------------------------------------
+/* */
+ExtractTar::~ExtractTar()
+{
+   // Error close
+   Done();
+}
+									/*}}}*/
+// ExtractTar::Done - Reap the gzip sub process				/*{{{*/
+bool ExtractTar::Done()
+{
+   return InFd.Close();
+}
+									/*}}}*/
+// ExtractTar::StartGzip - Startup gzip					/*{{{*/
+// ---------------------------------------------------------------------
+/* This creates a gzip sub process that has its input as the file itself.
+   If this tar file is embedded into something like an ar file then 
+   gzip will efficiently ignore the extra bits. */
+bool ExtractTar::StartGzip()
+{
+   if (DecompressProg.empty())
+   {
+      InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, FileFd::None, false);
+      return true;
+   }
+
+   std::vector<APT::Configuration::Compressor> const compressors = APT::Configuration::getCompressors();
+   std::vector<APT::Configuration::Compressor>::const_iterator compressor = compressors.begin();
+   for (; compressor != compressors.end(); ++compressor) {
+      if (compressor->Name == DecompressProg) {
+	 return InFd.OpenDescriptor(File.Fd(), FileFd::ReadOnly, *compressor, false);
+      }
+   }
+
+   return _error->Error(_("Cannot find a configured compressor for '%s'"),
+			DecompressProg.c_str());
+
+}
+									/*}}}*/
+// ExtractTar::Go - Perform extraction					/*{{{*/
+// ---------------------------------------------------------------------
+/* This reads each 512 byte block from the archive and extracts the header
+   information into the Item structure. Then it resolves the UID/GID and
+   invokes the correct processing function. */
+bool ExtractTar::Go(pkgDirStream &Stream)
+{   
+   if (StartGzip() == false)
+      return false;
+   
+   // Loop over all blocks
+   string LastLongLink, ItemLink;
+   string LastLongName, ItemName;
+   while (1)
+   {
+      bool BadRecord = false;      
+      unsigned char Block[512];      
+      if (InFd.Read(Block,sizeof(Block),true) == false)
+	 return false;
+      
+      if (InFd.Eof() == true)
+	 break;
+
+      // Get the checksum
+      TarHeader *Tar = (TarHeader *)Block;
+      unsigned long CheckSum;
+      if (StrToNum(Tar->Checksum,CheckSum,sizeof(Tar->Checksum),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+      
+      /* Compute the checksum field. The actual checksum is blanked out
+         with spaces so it is not included in the computation */
+      unsigned long NewSum = 0;
+      memset(Tar->Checksum,' ',sizeof(Tar->Checksum));
+      for (int I = 0; I != sizeof(Block); I++)
+	 NewSum += Block[I];
+      
+      /* Check for a block of nulls - in this case we kill gzip, GNU tar
+       	 does this.. */
+      if (NewSum == ' '*sizeof(Tar->Checksum))
+	 return Done();
+      
+      if (NewSum != CheckSum)
+	 return _error->Error(_("Tar checksum failed, archive corrupted"));
+   
+      // Decode all of the fields
+      pkgDirStream::Item Itm;
+      if (StrToNum(Tar->Mode,Itm.Mode,sizeof(Tar->Mode),8) == false ||
+          (Base256ToNum(Tar->UserID,Itm.UID,8) == false &&
+	     StrToNum(Tar->UserID,Itm.UID,sizeof(Tar->UserID),8) == false) ||
+          (Base256ToNum(Tar->GroupID,Itm.GID,8) == false &&
+	     StrToNum(Tar->GroupID,Itm.GID,sizeof(Tar->GroupID),8) == false) ||
+          (Base256ToNum(Tar->Size,Itm.Size,12) == false &&
+	     StrToNum(Tar->Size,Itm.Size,sizeof(Tar->Size),8) == false) ||
+          (Base256ToNum(Tar->MTime,Itm.MTime,12) == false &&
+	     StrToNum(Tar->MTime,Itm.MTime,sizeof(Tar->MTime),8) == false) ||
+	  StrToNum(Tar->Major,Itm.Major,sizeof(Tar->Major),8) == false ||
+	  StrToNum(Tar->Minor,Itm.Minor,sizeof(Tar->Minor),8) == false)
+	 return _error->Error(_("Corrupted archive"));
+
+      // Security check. Prevents overflows below the code when rounding up in skip/copy code,
+      // and provides modest protection against decompression bombs.
+      if (Itm.Size > APT_FILESIZE_LIMIT)
+	 return _error->Error("Tar member too large: %llu > %llu bytes", Itm.Size, APT_FILESIZE_LIMIT);
+
+      // Grab the filename and link target: use last long name if one was
+      // set, otherwise use the header value as-is, but remember that it may
+      // fill the entire 100-byte block and needs to be zero-terminated.
+      // See Debian Bug #689582.
+      if (LastLongName.empty() == false)
+	 Itm.Name = (char *)LastLongName.c_str();
+      else
+	 Itm.Name = (char *)ItemName.assign(Tar->Name, sizeof(Tar->Name)).c_str();
+      if (Itm.Name[0] == '.' && Itm.Name[1] == '/' && Itm.Name[2] != 0)
+	 Itm.Name += 2;
+
+      if (LastLongLink.empty() == false)
+	 Itm.LinkTarget = (char *)LastLongLink.c_str();
+      else
+	 Itm.LinkTarget = (char *)ItemLink.assign(Tar->LinkName, sizeof(Tar->LinkName)).c_str();
+
+      // Convert the type over
+      switch (Tar->LinkFlag)
+      {
+	 case NormalFile0:
+	 case NormalFile:
+	 Itm.Type = pkgDirStream::Item::File;
+	 break;
+	 
+	 case HardLink:
+	 Itm.Type = pkgDirStream::Item::HardLink;
+	 break;
+	 
+	 case SymbolicLink:
+	 Itm.Type = pkgDirStream::Item::SymbolicLink;
+	 break;
+	 
+	 case CharacterDevice:
+	 Itm.Type = pkgDirStream::Item::CharDevice;
+	 break;
+	    
+	 case BlockDevice:
+	 Itm.Type = pkgDirStream::Item::BlockDevice;
+	 break;
+	 
+	 case Directory:
+	 Itm.Type = pkgDirStream::Item::Directory;
+	 break;
+	 
+	 case FIFO:
+	 Itm.Type = pkgDirStream::Item::FIFO;
+	 break;
+
+	 case GNU_LongLink:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length <= sizeof(Block))
+	       {
+		  LastLongLink.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongLink.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 case GNU_LongName:
+	 {
+	    unsigned long long Length = Itm.Size;
+	    unsigned char Block[512];
+	    if (Length > APT_LONGNAME_LIMIT)
+	       return _error->Error("Long name to large: %llu bytes > %llu bytes", Length, APT_LONGNAME_LIMIT);
+	    while (Length > 0)
+	    {
+	       if (InFd.Read(Block,sizeof(Block),true) == false)
+		  return false;
+	       if (Length < sizeof(Block))
+	       {
+		  LastLongName.append(Block,Block+sizeof(Block));
+		  break;
+	       }	       
+	       LastLongName.append(Block,Block+sizeof(Block));
+	       Length -= sizeof(Block);
+	    }
+	    continue;
+	 }
+	 
+	 default:
+	 BadRecord = true;
+	 _error->Warning(_("Unknown TAR header type %u"), (unsigned)Tar->LinkFlag);
+	 break;
+      }
+
+      int Fd = -1;
+      if (not BadRecord && not Stream.DoItem(Itm, Fd))
+	 return false;
+
+      if (Fd == -1 || Fd < -2 || BadRecord)
+      {
+	 if (Itm.Size > 0 && not InFd.Skip(((Itm.Size + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	    return false;
+      }
+      else if (Itm.Size != 0)
+      {
+	 // Copy the file over the FD
+	 auto Size = Itm.Size;
+	 unsigned char Junk[32*1024];
+	 do
+	 {
+	    auto const Read = std::min<unsigned long long>(Size, sizeof(Junk));
+	    if (not InFd.Read(Junk, ((Read + (sizeof(Block) - 1)) / sizeof(Block)) * sizeof(Block)))
+	       return false;
+
+	    if (Fd > 0)
+	    {
+	       if (not FileFd::Write(Fd, Junk, Read))
+		  return Stream.Fail(Itm, Fd);
+	    }
+	    // An Fd of -2 means to send to a special processing function
+	    else if (Fd == -2)
+	    {
+	       if (not Stream.Process(Itm, Junk, Read, Itm.Size - Size))
+		  return Stream.Fail(Itm, Fd);
+	    }
+
+	    Size -= Read;
+	 } while (Size != 0);
+      }
+
+      // And finish up
+      if (not BadRecord && not Stream.FinishedFile(Itm, Fd))
+	 return false;
+      LastLongName.erase();
+      LastLongLink.erase();
+   }
+
+   return Done();
+}
+									/*}}}*/