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-rw-r--r--apt-pkg/deb/debfile.cc274
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+// -*- mode: cpp; mode: fold -*-
+// Description /*{{{*/
+/* ######################################################################
+
+ Debian Archive File (.deb)
+
+ .DEB archives are AR files containing two tars and an empty marker
+ member called 'debian-binary'. The two tars contain the meta data and
+ the actual archive contents. Thus this class is a very simple wrapper
+ around ar/tar to simply extract the right tar files.
+
+ It also uses the deb package list parser to parse the control file
+ into the cache.
+
+ ##################################################################### */
+ /*}}}*/
+// Include Files /*{{{*/
+#include <config.h>
+
+#include <apt-pkg/aptconfiguration.h>
+#include <apt-pkg/arfile.h>
+#include <apt-pkg/debfile.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 <apt-pkg/tagfile.h>
+
+#include <algorithm>
+#include <string>
+#include <sstream>
+#include <vector>
+#include <string.h>
+#include <sys/stat.h>
+
+#include <apti18n.h>
+ /*}}}*/
+
+// DebFile::debDebFile - Constructor /*{{{*/
+// ---------------------------------------------------------------------
+/* Open the AR file and check for consistency */
+debDebFile::debDebFile(FileFd &File) : File(File), AR(File)
+{
+ if (_error->PendingError() == true)
+ return;
+
+ if (!CheckMember("debian-binary")) {
+ _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "debian-binary");
+ return;
+ }
+
+ if (!CheckMember("control.tar") &&
+ !CheckMember("control.tar.gz") &&
+ !CheckMember("control.tar.xz") &&
+ !CheckMember("control.tar.zst"))
+ {
+ _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "control.tar");
+ return;
+ }
+
+ if (!CheckMember("data.tar") &&
+ !CheckMember("data.tar.gz") &&
+ !CheckMember("data.tar.bz2") &&
+ !CheckMember("data.tar.lzma") &&
+ !CheckMember("data.tar.xz") &&
+ !CheckMember("data.tar.zst"))
+ {
+ _error->Error(_("This is not a valid DEB archive, missing '%s' member"), "data.tar");
+ return;
+ }
+}
+ /*}}}*/
+// DebFile::CheckMember - Check if a named member is in the archive /*{{{*/
+// ---------------------------------------------------------------------
+/* This is used to check for a correct deb and to give nicer error messages
+ for people playing around. */
+bool debDebFile::CheckMember(const char *Name)
+{
+ if (AR.FindMember(Name) == 0)
+ return false;
+ return true;
+}
+ /*}}}*/
+// DebFile::GotoMember - Jump to a Member /*{{{*/
+// ---------------------------------------------------------------------
+/* Jump in the file to the start of a named member and return the information
+ about that member. The caller can then read from the file up to the
+ returned size. Note, since this relies on the file position this is
+ a destructive operation, it also changes the last returned Member
+ structure - so don't nest them! */
+const ARArchive::Member *debDebFile::GotoMember(const char *Name)
+{
+ // Get the archive member and positition the file
+ const ARArchive::Member *Member = AR.FindMember(Name);
+ if (Member == 0)
+ {
+ return 0;
+ }
+ if (File.Seek(Member->Start) == false)
+ return 0;
+
+ return Member;
+}
+ /*}}}*/
+// DebFile::ExtractTarMember - Extract the contents of a tar member /*{{{*/
+// ---------------------------------------------------------------------
+/* Simple wrapper around tar.. */
+bool debDebFile::ExtractTarMember(pkgDirStream &Stream,const char *Name)
+{
+ std::string Compressor;
+ auto const Compressors = APT::Configuration::getCompressors();
+
+ ARArchive::Member const *Member = AR.FindMember(Name);
+ if (Member != nullptr)
+ {
+ auto const found = std::find_if(Compressors.cbegin(), Compressors.cend(), [&](auto const &c) {
+ return not c.Extension.empty() && APT::String::Endswith(Name, c.Extension);
+ });
+ if (found != Compressors.cend())
+ Compressor = found->Name;
+ }
+ else
+ {
+ for (auto const &c : Compressors)
+ {
+ if (c.Extension.empty())
+ continue;
+ Member = AR.FindMember(std::string(Name).append(c.Extension).c_str());
+ if (Member == nullptr)
+ continue;
+ Compressor = c.Name;
+ break;
+ }
+ }
+
+ if (Member == nullptr)
+ {
+ std::ostringstream ext;
+ ext << Name << '{';
+ for (auto const &c : Compressors)
+ if (not c.Extension.empty())
+ ext << c.Extension << ',';
+ ext << '}';
+ return _error->Error(_("Internal error, could not locate member %s"), ext.str().c_str());
+ }
+
+ if (not File.Seek(Member->Start))
+ return false;
+
+ ExtractTar Tar(File,Member->Size,Compressor);
+ if (_error->PendingError())
+ return false;
+ return Tar.Go(Stream);
+}
+ /*}}}*/
+// DebFile::ExtractArchive - Extract the archive data itself /*{{{*/
+// ---------------------------------------------------------------------
+/* Simple wrapper around DebFile::ExtractTarMember. */
+bool debDebFile::ExtractArchive(pkgDirStream &Stream)
+{
+ return ExtractTarMember(Stream, "data.tar");
+}
+ /*}}}*/
+
+// DebFile::ControlExtract::DoItem - Control Tar Extraction /*{{{*/
+// ---------------------------------------------------------------------
+/* This directory stream handler for the control tar handles extracting
+ it into the temporary meta directory. It only extracts files, it does
+ not create directories, links or anything else. */
+bool debDebFile::ControlExtract::DoItem(Item &Itm,int &Fd)
+{
+ if (Itm.Type != Item::File)
+ return true;
+
+ /* Cleanse the file name, prevent people from trying to unpack into
+ absolute paths, .., etc */
+ for (char *I = Itm.Name; *I != 0; I++)
+ if (*I == '/')
+ *I = '_';
+
+ /* Force the ownership to be root and ensure correct permissions,
+ go-w, the rest are left untouched */
+ Itm.UID = 0;
+ Itm.GID = 0;
+ Itm.Mode &= ~(S_IWGRP | S_IWOTH);
+
+ return pkgDirStream::DoItem(Itm,Fd);
+}
+ /*}}}*/
+
+// MemControlExtract::DoItem - Check if it is the control file /*{{{*/
+// ---------------------------------------------------------------------
+/* This sets up to extract the control block member file into a memory
+ block of just the right size. All other files go into the bit bucket. */
+
+// Upper size limit for control files. Two reasons for having a limit here:
+//
+// 1. We read those files into memory and want to avoid being killed by OOM
+//
+// 2. We allocate (Itm.Size+2)-large arrays, so this can overflow if Itm.Size
+// becomes 2**64-2 or larger. This is obviously
+//
+// 64 MiB seems like a terribly large size that everyone should be happy with.
+static const unsigned long long DEB_CONTROL_SIZE_LIMIT = 64 * 1024 * 1024;
+bool debDebFile::MemControlExtract::DoItem(Item &Itm,int &Fd)
+{
+ // At the control file, allocate buffer memory.
+ if (Member == Itm.Name)
+ {
+ if (Itm.Size > DEB_CONTROL_SIZE_LIMIT)
+ return _error->Error("Control file too large: %llu > %llu bytes", Itm.Size, DEB_CONTROL_SIZE_LIMIT);
+ delete [] Control;
+ Control = new char[Itm.Size+2];
+ IsControl = true;
+ Fd = -2; // Signal to pass to Process
+ Length = Itm.Size;
+ }
+ else
+ IsControl = false;
+
+ return true;
+}
+ /*}}}*/
+// MemControlExtract::Process - Process extracting the control file /*{{{*/
+// ---------------------------------------------------------------------
+/* Just memcopy the block from the tar extractor and put it in the right
+ place in the pre-allocated memory block. */
+bool debDebFile::MemControlExtract::Process(Item &/*Itm*/,const unsigned char *Data,
+ unsigned long long Size,unsigned long long Pos)
+{
+ memcpy(Control + Pos, Data,Size);
+ return true;
+}
+ /*}}}*/
+// MemControlExtract::Read - Read the control information from the deb /*{{{*/
+// ---------------------------------------------------------------------
+/* This uses the internal tar extractor to fetch the control file, and then
+ it parses it into a tag section parser. */
+bool debDebFile::MemControlExtract::Read(debDebFile &Deb)
+{
+ if (Deb.ExtractTarMember(*this, "control.tar") == false)
+ return false;
+
+ if (Control == 0)
+ return true;
+
+ Control[Length] = '\n';
+ Control[Length+1] = '\n';
+ if (Section.Scan(Control,Length+2) == false)
+ return _error->Error(_("Unparsable control file"));
+ return true;
+}
+ /*}}}*/
+// MemControlExtract::TakeControl - Parse a memory block /*{{{*/
+// ---------------------------------------------------------------------
+/* The given memory block is loaded into the parser and parsed as a control
+ record. */
+bool debDebFile::MemControlExtract::TakeControl(const void *Data,unsigned long long Size)
+{
+ if (Size > DEB_CONTROL_SIZE_LIMIT)
+ return _error->Error("Control file too large: %llu > %llu bytes", Size, DEB_CONTROL_SIZE_LIMIT);
+
+ delete [] Control;
+ Control = new char[Size+2];
+ Length = Size;
+ memcpy(Control,Data,Size);
+
+ Control[Length] = '\n';
+ Control[Length+1] = '\n';
+ return Section.Scan(Control,Length+2);
+}
+ /*}}}*/
+