X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/8e0002ac420707b94a8a43dfedea7fc182dd5851..7e4dfb4349e909c15b1c777679fdae81d76eeb62:/apt-pkg/contrib/fileutl.cc diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index c7c60e00e..c5eb56f0e 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -47,6 +47,8 @@ #include #include #include +#include +#include #include #include @@ -58,12 +60,13 @@ #include #endif #ifdef HAVE_LZMA - #include #include #endif +#include +#include -#ifdef WORDS_BIGENDIAN -#include +#if __gnu_linux__ +#include #endif #include @@ -855,6 +858,27 @@ bool ExecWait(pid_t Pid,const char *Name,bool Reap) } /*}}}*/ + +// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned /*{{{*/ +// --------------------------------------------------------------------- +/* */ +bool StartsWithGPGClearTextSignature(string const &FileName) +{ + static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----\n"; + char buffer[strlen(SIGMSG)+1]; + FILE* gpg = fopen(FileName.c_str(), "r"); + if (gpg == NULL) + return false; + + char const * const test = fgets(buffer, sizeof(buffer), gpg); + fclose(gpg); + if (test == NULL || strcmp(buffer, SIGMSG) != 0) + return false; + + return true; +} + + class FileFdPrivate { /*{{{*/ public: #ifdef HAVE_ZLIB @@ -872,7 +896,7 @@ class FileFdPrivate { /*{{{*/ bool eof; bool compressing; - LZMAFILE() : file(NULL), eof(false), compressing(false) {} + LZMAFILE() : file(NULL), eof(false), compressing(false) { buffer[0] = '\0'; } ~LZMAFILE() { if (compressing == true) { @@ -1260,7 +1284,8 @@ bool FileFd::OpenInternDescriptor(unsigned int const Mode, APT::Configuration::C if (d->lzma == NULL) d->lzma = new FileFdPrivate::LZMAFILE; d->lzma->file = (FILE*) compress_struct; - d->lzma->stream = LZMA_STREAM_INIT; + lzma_stream tmp_stream = LZMA_STREAM_INIT; + d->lzma->stream = tmp_stream; if ((Mode & ReadWrite) == ReadWrite) return FileFdError("ReadWrite mode is not supported for file %s", FileName.c_str()); @@ -1500,7 +1525,7 @@ bool FileFd::Read(void *To,unsigned long long Size,unsigned long long *Actual) int err; char const * const errmsg = BZ2_bzerror(d->bz2, &err); if (err != BZ_IO_ERROR) - return FileFdError("BZ2_bzread: %s (%d: %s)", _("Read error"), err, errmsg); + return FileFdError("BZ2_bzread: %s %s (%d: %s)", FileName.c_str(), _("Read error"), err, errmsg); } #endif #ifdef HAVE_LZMA @@ -1816,7 +1841,8 @@ static bool StatFileFd(char const * const msg, int const iFd, std::string const // higher-level code will generate more meaningful messages, // even translated this would be meaningless for users return _error->Errno("fstat", "Unable to determine %s for fd %i", msg, iFd); - ispipe = S_ISFIFO(Buf.st_mode); + if (FileName.empty() == false) + ispipe = S_ISFIFO(Buf.st_mode); } // for compressor pipes st_size is undefined and at 'best' zero @@ -1896,19 +1922,13 @@ unsigned long long FileFd::Size() FileFdErrno("lseek","Unable to seek to end of gzipped file"); return 0; } - size = 0; + uint32_t size = 0; if (read(iFd, &size, 4) != 4) { FileFdErrno("read","Unable to read original size of gzipped file"); return 0; } - -#ifdef WORDS_BIGENDIAN - uint32_t tmp_size = size; - uint8_t const * const p = (uint8_t const * const) &tmp_size; - tmp_size = (p[3] << 24) | (p[2] << 16) | (p[1] << 8) | p[0]; - size = tmp_size; -#endif + size = le32toh(size); if (lseek(iFd, oldPos, SEEK_SET) < 0) { @@ -2106,10 +2126,8 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode) int Pipe[2] = {-1, -1}; if(pipe(Pipe) != 0) - { return _error->Errno("pipe", _("Failed to create subprocess IPC")); - return NULL; - } + std::set keep_fds; keep_fds.insert(Pipe[0]); keep_fds.insert(Pipe[1]); @@ -2152,3 +2170,92 @@ bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode) return true; } + +bool DropPrivs() +{ + // uid will be 0 in the end, but gid might be different anyway + uid_t old_uid = getuid(); + gid_t old_gid = getgid(); + + if (old_uid != 0) + return true; + if(_config->FindB("Debug::NoDropPrivs", false) == true) + return true; + + const std::string toUser = _config->Find("APT::Sandbox::User", "_apt"); + struct passwd *pw = getpwnam(toUser.c_str()); + if (pw == NULL) + return _error->Error("No user %s, can not drop rights", toUser.c_str()); + +#if __gnu_linux__ + // see prctl(2), needs linux3.5 + int ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0,0, 0); + if(ret < 0) + _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret); +#endif + // Do not change the order here, it might break things + if (setgroups(1, &pw->pw_gid)) + return _error->Errno("setgroups", "Failed to setgroups"); + + if (setegid(pw->pw_gid) != 0) + return _error->Errno("setegid", "Failed to setegid"); + + if (setgid(pw->pw_gid) != 0) + return _error->Errno("setgid", "Failed to setgid"); + + if (setuid(pw->pw_uid) != 0) + return _error->Errno("setuid", "Failed to setuid"); + + // the seteuid() is probably uneeded (at least thats what the linux + // man-page says about setuid(2)) but we cargo culted it anyway + if (seteuid(pw->pw_uid) != 0) + return _error->Errno("seteuid", "Failed to seteuid"); + + // Verify that the user has only a single group, and the correct one + gid_t groups[1]; + if (getgroups(1, groups) != 1) + return _error->Errno("getgroups", "Could not get new groups"); + if (groups[0] != pw->pw_gid) + return _error->Error("Could not switch group"); + + // Verify that gid, egid, uid, and euid changed + if (getgid() != pw->pw_gid) + return _error->Error("Could not switch group"); + if (getegid() != pw->pw_gid) + return _error->Error("Could not switch effective group"); + if (getuid() != pw->pw_uid) + return _error->Error("Could not switch user"); + if (geteuid() != pw->pw_uid) + return _error->Error("Could not switch effective user"); + +#ifdef HAVE_GETRESUID + // verify that the saved set-user-id was changed as well + uid_t ruid = 0; + uid_t euid = 0; + uid_t suid = 0; + if (getresuid(&ruid, &euid, &suid)) + return _error->Errno("getresuid", "Could not get saved set-user-ID"); + if (suid != pw->pw_uid) + return _error->Error("Could not switch saved set-user-ID"); +#endif + +#ifdef HAVE_GETRESGID + // verify that the saved set-group-id was changed as well + gid_t rgid = 0; + gid_t egid = 0; + gid_t sgid = 0; + if (getresgid(&rgid, &egid, &sgid)) + return _error->Errno("getresuid", "Could not get saved set-group-ID"); + if (sgid != pw->pw_gid) + return _error->Error("Could not switch saved set-group-ID"); +#endif + + // Check that uid and gid changes do not work anymore + if (pw->pw_gid != old_gid && (setgid(old_gid) != -1 || setegid(old_gid) != -1)) + return _error->Error("Could restore a gid to root, privilege dropping did not work"); + + if (pw->pw_uid != old_uid && (setuid(old_uid) != -1 || seteuid(old_uid) != -1)) + return _error->Error("Could restore a uid to root, privilege dropping did not work"); + + return true; +}