X-Git-Url: https://git.saurik.com/apt.git/blobdiff_plain/a943fbf21ca0b9b58b8f1492fc518679b1d7c749..eed4639e3feea0dd4ebedfac95fb5428753b795f:/apt-pkg/contrib/fileutl.cc diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc index 3e592d94f..837edef4b 100644 --- a/apt-pkg/contrib/fileutl.cc +++ b/apt-pkg/contrib/fileutl.cc @@ -52,6 +52,7 @@ #include #include +#include #ifdef HAVE_ZLIB #include @@ -159,7 +160,7 @@ bool CopyFile(FileFd &From,FileFd &To) return false; // Buffered copy between fds - SPtrArray Buf = new unsigned char[64000]; + std::unique_ptr Buf(new unsigned char[64000]); unsigned long long Size = From.Size(); while (Size != 0) { @@ -167,8 +168,8 @@ bool CopyFile(FileFd &From,FileFd &To) if (Size > 64000) ToRead = 64000; - if (From.Read(Buf,ToRead) == false || - To.Write(Buf,ToRead) == false) + if (From.Read(Buf.get(),ToRead) == false || + To.Write(Buf.get(),ToRead) == false) return false; Size -= ToRead; @@ -800,11 +801,26 @@ pid_t ExecFork(std::set KeepFDs) signal(SIGCONT,SIG_DFL); signal(SIGTSTP,SIG_DFL); - // Close all of our FDs - just in case - for (int K = 3; K != sysconf(_SC_OPEN_MAX); K++) + DIR *dir = opendir("/proc/self/fd"); + if (dir != NULL) { - if(KeepFDs.find(K) == KeepFDs.end()) - fcntl(K,F_SETFD,FD_CLOEXEC); + struct dirent *ent; + while ((ent = readdir(dir))) + { + int fd = atoi(ent->d_name); + // If fd > 0, it was a fd number and not . or .. + if (fd >= 3 && KeepFDs.find(fd) == KeepFDs.end()) + fcntl(fd,F_SETFD,FD_CLOEXEC); + } + closedir(dir); + } else { + long ScOpenMax = sysconf(_SC_OPEN_MAX); + // Close all of our FDs - just in case + for (int K = 3; K != ScOpenMax; K++) + { + if(KeepFDs.find(K) == KeepFDs.end()) + fcntl(K,F_SETFD,FD_CLOEXEC); + } } } @@ -874,6 +890,25 @@ bool StartsWithGPGClearTextSignature(string const &FileName) return true; } /*}}}*/ +// ChangeOwnerAndPermissionOfFile - set file attributes to requested values /*{{{*/ +bool ChangeOwnerAndPermissionOfFile(char const * const requester, char const * const file, char const * const user, char const * const group, mode_t const mode) +{ + if (strcmp(file, "/dev/null") == 0) + return true; + bool Res = true; + if (getuid() == 0 && strlen(user) != 0 && strlen(group) != 0) // if we aren't root, we can't chown, so don't try it + { + // ensure the file is owned by root and has good permissions + struct passwd const * const pw = getpwnam(user); + struct group const * const gr = getgrnam(group); + if (pw != NULL && gr != NULL && chown(file, pw->pw_uid, gr->gr_gid) != 0) + Res &= _error->WarningE(requester, "chown to %s:%s of file %s failed", user, group, file); + } + if (chmod(file, mode) != 0) + Res &= _error->WarningE(requester, "chmod 0%o of file %s failed", mode, file); + return Res; +} + /*}}}*/ class FileFdPrivate { /*{{{*/ public: @@ -991,6 +1026,25 @@ class FileFdPrivate { /*{{{*/ ~FileFdPrivate() { CloseDown(""); } }; /*}}}*/ +// FileFd Constructors /*{{{*/ +FileFd::FileFd(std::string FileName,unsigned int const Mode,unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL) +{ + Open(FileName,Mode, None, AccessMode); +} +FileFd::FileFd(std::string FileName,unsigned int const Mode, CompressMode Compress, unsigned long AccessMode) : iFd(-1), Flags(0), d(NULL) +{ + Open(FileName,Mode, Compress, AccessMode); +} +FileFd::FileFd() : iFd(-1), Flags(AutoClose), d(NULL) {} +FileFd::FileFd(int const Fd, unsigned int const Mode, CompressMode Compress) : iFd(-1), Flags(0), d(NULL) +{ + OpenDescriptor(Fd, Mode, Compress); +} +FileFd::FileFd(int const Fd, bool const AutoClose) : iFd(-1), Flags(0), d(NULL) +{ + OpenDescriptor(Fd, ReadWrite, None, AutoClose); +} + /*}}}*/ // FileFd::Open - Open a file /*{{{*/ // --------------------------------------------------------------------- /* The most commonly used open mode combinations are given with Mode */ @@ -1952,12 +2006,13 @@ bool FileFd::Close() { if ((Flags & Compressed) != Compressed && iFd > 0 && close(iFd) != 0) Res &= _error->Errno("close",_("Problem closing the file %s"), FileName.c_str()); - if (d != NULL) - { - Res &= d->CloseDown(FileName); - delete d; - d = NULL; - } + } + + if (d != NULL) + { + Res &= d->CloseDown(FileName); + delete d; + d = NULL; } if ((Flags & Replace) == Replace) { @@ -2066,36 +2121,64 @@ std::string GetTempDir() /*{{{*/ tmpdir = P_tmpdir; #endif - // check that tmpdir is set and exists struct stat st; - if (!tmpdir || strlen(tmpdir) == 0 || stat(tmpdir, &st) != 0) + if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set + stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0) // exists and is directory + tmpdir = "/tmp"; + else if (geteuid() != 0 && // root can do everything anyway + faccessat(-1, tmpdir, R_OK | W_OK | X_OK, AT_EACCESS | AT_SYMLINK_NOFOLLOW) != 0) // current user has rwx access to directory tmpdir = "/tmp"; return string(tmpdir); +} +std::string GetTempDir(std::string const &User) +{ + // no need/possibility to drop privs + if(getuid() != 0 || User.empty() || User == "root") + return GetTempDir(); + + struct passwd const * const pw = getpwnam(User.c_str()); + if (pw == NULL) + return GetTempDir(); + + gid_t const old_euid = geteuid(); + gid_t const old_egid = getegid(); + if (setegid(pw->pw_gid) != 0) + _error->Errno("setegid", "setegid %u failed", pw->pw_gid); + if (seteuid(pw->pw_uid) != 0) + _error->Errno("seteuid", "seteuid %u failed", pw->pw_uid); + + std::string const tmp = GetTempDir(); + + if (seteuid(old_euid) != 0) + _error->Errno("seteuid", "seteuid %u failed", old_euid); + if (setegid(old_egid) != 0) + _error->Errno("setegid", "setegid %u failed", old_egid); + + return tmp; } /*}}}*/ -FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink) /*{{{*/ +FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink, FileFd * const TmpFd) /*{{{*/ { char fn[512]; - FileFd *Fd = new FileFd(); + FileFd * const Fd = TmpFd == NULL ? new FileFd() : TmpFd; - std::string tempdir = GetTempDir(); - snprintf(fn, sizeof(fn), "%s/%s.XXXXXX", + std::string const tempdir = GetTempDir(); + snprintf(fn, sizeof(fn), "%s/%s.XXXXXX", tempdir.c_str(), Prefix.c_str()); - int fd = mkstemp(fn); + int const fd = mkstemp(fn); if(ImmediateUnlink) unlink(fn); - if (fd < 0) + if (fd < 0) { _error->Errno("GetTempFile",_("Unable to mkstemp %s"), fn); return NULL; } - if (!Fd->OpenDescriptor(fd, FileFd::WriteOnly, FileFd::None, true)) + if (!Fd->OpenDescriptor(fd, FileFd::ReadWrite, FileFd::None, true)) { _error->Errno("GetTempFile",_("Unable to write to %s"),fn); return NULL; } - return Fd; } /*}}}*/ @@ -2179,6 +2262,12 @@ bool DropPrivileges() /*{{{*/ _error->Warning("PR_SET_NO_NEW_PRIVS failed with %i", ret); #endif + // empty setting disables privilege dropping - this also ensures + // backward compatibility, see bug #764506 + const std::string toUser = _config->Find("APT::Sandbox::User"); + if (toUser.empty()) + return true; + // uid will be 0 in the end, but gid might be different anyway uid_t const old_uid = getuid(); gid_t const old_gid = getgid(); @@ -2186,28 +2275,37 @@ bool DropPrivileges() /*{{{*/ if (old_uid != 0) 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()); // Do not change the order here, it might break things + // Get rid of all our supplementary groups first if (setgroups(1, &pw->pw_gid)) return _error->Errno("setgroups", "Failed to setgroups"); + // Now change the group ids to the new user +#ifdef HAVE_SETRESGID + if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0) + return _error->Errno("setresgid", "Failed to set new group ids"); +#else 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"); +#endif + // Change the user ids to the new user +#ifdef HAVE_SETRESUID + if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0) + return _error->Errno("setresuid", "Failed to set new user ids"); +#else 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"); +#endif // Verify that the user has only a single group, and the correct one gid_t groups[1];