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Diffstat (limited to 'apt-pkg/deb/debfile.cc')
| -rw-r--r-- | apt-pkg/deb/debfile.cc | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/apt-pkg/deb/debfile.cc b/apt-pkg/deb/debfile.cc new file mode 100644 index 0000000..1d61c82 --- /dev/null +++ b/apt-pkg/deb/debfile.cc @@ -0,0 +1,274 @@ +// -*- 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 <cstring> +#include <sstream> +#include <string> +#include <vector> +#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); +} + /*}}}*/ + |