#include <signal.h>
#include <errno.h>
#include <glob.h>
+#include <pwd.h>
+#include <grp.h>
#include <set>
#include <algorithm>
+#include <memory>
#ifdef HAVE_ZLIB
#include <zlib.h>
#include <endian.h>
#include <stdint.h>
+#if __gnu_linux__
+#include <sys/prctl.h>
+#endif
+
#include <apti18n.h>
/*}}}*/
if (From.IsOpen() == false || To.IsOpen() == false ||
From.Failed() == true || To.Failed() == true)
return false;
-
+
// Buffered copy between fds
- SPtrArray<unsigned char> Buf = new unsigned char[64000];
- unsigned long long Size = From.Size();
- while (Size != 0)
- {
- unsigned long long ToRead = Size;
- if (Size > 64000)
- ToRead = 64000;
-
- if (From.Read(Buf,ToRead) == false ||
- To.Write(Buf,ToRead) == false)
+ std::unique_ptr<unsigned char[]> Buf(new unsigned char[64000]);
+ constexpr unsigned long long BufSize = sizeof(Buf.get())/sizeof(Buf.get()[0]);
+ unsigned long long ToRead = 0;
+ do {
+ if (From.Read(Buf.get(),BufSize, &ToRead) == false ||
+ To.Write(Buf.get(),ToRead) == false)
return false;
-
- Size -= ToRead;
- }
+ } while (ToRead != 0);
+
+ return true;
+}
+ /*}}}*/
+bool RemoveFile(char const * const Function, std::string const &FileName)/*{{{*/
+{
+ if (FileName == "/dev/null")
+ return true;
+ errno = 0;
+ if (unlink(FileName.c_str()) != 0)
+ {
+ if (errno == ENOENT)
+ return true;
- return true;
+ return _error->WarningE(Function,_("Problem unlinking the file %s"), FileName.c_str());
+ }
+ return true;
}
/*}}}*/
// GetLock - Gets a lock file /*{{{*/
char *p = realpath(File.c_str(), NULL);
if (p == NULL)
{
- _error->Errno("realpath", "flAbsPath failed");
+ _error->Errno("realpath", "flAbsPath on %s failed", File.c_str());
return "";
}
std::string AbsPath(p);
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);
+ }
}
}
return true;
}
/*}}}*/
-
-
-// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned /*{{{*/
-// ---------------------------------------------------------------------
-/* */
+// StartsWithGPGClearTextSignature - Check if a file is Pgp/GPG clearsigned /*{{{*/
bool StartsWithGPGClearTextSignature(string const &FileName)
{
static const char* SIGMSG = "-----BEGIN PGP SIGNED MESSAGE-----\n";
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:
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)
{
~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 */
if ((Mode & ReadWrite) == 0)
return FileFdError("No openmode provided in FileFd::Open for %s", FileName.c_str());
- if ((Mode & Atomic) == Atomic)
+ unsigned int OpenMode = Mode;
+ if (FileName == "/dev/null")
+ OpenMode = OpenMode & ~(Atomic | Exclusive | Create | Empty);
+
+ if ((OpenMode & Atomic) == Atomic)
{
Flags |= Replace;
}
- else if ((Mode & (Exclusive | Create)) == (Exclusive | Create))
+ else if ((OpenMode & (Exclusive | Create)) == (Exclusive | Create))
{
// for atomic, this will be done by rename in Close()
- unlink(FileName.c_str());
+ RemoveFile("FileFd::Open", FileName);
}
- if ((Mode & Empty) == Empty)
+ if ((OpenMode & Empty) == Empty)
{
struct stat Buf;
if (lstat(FileName.c_str(),&Buf) == 0 && S_ISLNK(Buf.st_mode))
- unlink(FileName.c_str());
+ RemoveFile("FileFd::Open", FileName);
}
int fileflags = 0;
- #define if_FLAGGED_SET(FLAG, MODE) if ((Mode & FLAG) == FLAG) fileflags |= MODE
+ #define if_FLAGGED_SET(FLAG, MODE) if ((OpenMode & FLAG) == FLAG) fileflags |= MODE
if_FLAGGED_SET(ReadWrite, O_RDWR);
else if_FLAGGED_SET(ReadOnly, O_RDONLY);
else if_FLAGGED_SET(WriteOnly, O_WRONLY);
if_FLAGGED_SET(Exclusive, O_EXCL);
#undef if_FLAGGED_SET
- if ((Mode & Atomic) == Atomic)
+ if ((OpenMode & Atomic) == Atomic)
{
char *name = strdup((FileName + ".XXXXXX").c_str());
iFd = open(FileName.c_str(), fileflags, AccessMode);
this->FileName = FileName;
- if (iFd == -1 || OpenInternDescriptor(Mode, compressor) == false)
+ if (iFd == -1 || OpenInternDescriptor(OpenMode, compressor) == false)
{
if (iFd != -1)
{
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
{
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) {
if ((Flags & Fail) == Fail && (Flags & DelOnFail) == DelOnFail &&
FileName.empty() == false)
- if (unlink(FileName.c_str()) != 0)
- Res &= _error->WarningE("unlnk",_("Problem unlinking the file %s"), FileName.c_str());
+ Res &= RemoveFile("FileFd::Close", FileName);
if (Res == false)
Flags |= Fail;
}
/*}}}*/
-APT_DEPRECATED gzFile FileFd::gzFd() {
+gzFile FileFd::gzFd() {
#ifdef HAVE_ZLIB
return d->gz;
#else
#endif
}
-
-// Glob - wrapper around "glob()" /*{{{*/
-// ---------------------------------------------------------------------
-/* */
+// Glob - wrapper around "glob()" /*{{{*/
std::vector<std::string> Glob(std::string const &pattern, int flags)
{
std::vector<std::string> result;
return result;
}
/*}}}*/
-
-std::string GetTempDir()
+std::string GetTempDir() /*{{{*/
{
const char *tmpdir = getenv("TMPDIR");
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();
-FileFd* GetTempFile(std::string const &Prefix, bool ImmediateUnlink)
+ 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 * 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;
}
-
-bool Rename(std::string From, std::string To)
+ /*}}}*/
+bool Rename(std::string From, std::string To) /*{{{*/
{
if (rename(From.c_str(),To.c_str()) != 0)
{
_error->Error(_("rename failed, %s (%s -> %s)."),strerror(errno),
From.c_str(),To.c_str());
return false;
- }
+ }
return true;
}
-
-bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)
+ /*}}}*/
+bool Popen(const char* Args[], FileFd &Fd, pid_t &Child, FileFd::OpenMode Mode)/*{{{*/
{
int fd;
if (Mode != FileFd::ReadOnly && Mode != FileFd::WriteOnly)
int Pipe[2] = {-1, -1};
if(pipe(Pipe) != 0)
- {
return _error->Errno("pipe", _("Failed to create subprocess IPC"));
- return NULL;
- }
+
std::set<int> keep_fds;
keep_fds.insert(Pipe[0]);
keep_fds.insert(Pipe[1]);
{
close(Pipe[1]);
fd = Pipe[0];
- } else if(Mode == FileFd::WriteOnly)
+ }
+ else if(Mode == FileFd::WriteOnly)
{
close(Pipe[0]);
fd = Pipe[1];
}
+ else
+ return _error->Error("Popen supports ReadOnly (x)or WriteOnly mode only");
Fd.OpenDescriptor(fd, Mode, FileFd::None, true);
return true;
}
+ /*}}}*/
+bool DropPrivileges() /*{{{*/
+{
+ if(_config->FindB("Debug::NoDropPrivs", false) == true)
+ return true;
+
+#if __gnu_linux__
+#if defined(PR_SET_NO_NEW_PRIVS) && ( PR_SET_NO_NEW_PRIVS != 38 )
+#error "PR_SET_NO_NEW_PRIVS is defined, but with a different value than expected!"
+#endif
+ // see prctl(2), needs linux3.5 at runtime - magic constant to avoid it at buildtime
+ int ret = prctl(38, 1, 0, 0, 0);
+ // ignore EINVAL - kernel is too old to understand the option
+ if(ret < 0 && errno != EINVAL)
+ _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() || toUser == "root")
+ return true;
+
+ // a lot can go wrong trying to drop privileges completely,
+ // so ideally we would like to verify that we have done it –
+ // but the verify asks for too much in case of fakeroot (and alike)
+ // [Specific checks can be overridden with dedicated options]
+ bool const VerifySandboxing = _config->FindB("APT::Sandbox::Verify", false);
+
+ // 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();
+
+ if (old_uid != 0)
+ return true;
+
+ 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");
+ if (seteuid(pw->pw_uid) != 0)
+ return _error->Errno("seteuid", "Failed to seteuid");
+#endif
+
+ // disabled by default as fakeroot doesn't implement getgroups currently (#806521)
+ if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Groups", false) == true)
+ {
+ // Verify that the user isn't still in any supplementary groups
+ long const ngroups_max = sysconf(_SC_NGROUPS_MAX);
+ std::unique_ptr<gid_t[]> gidlist(new gid_t[ngroups_max]);
+ if (unlikely(gidlist == NULL))
+ return _error->Error("Allocation of a list of size %lu for getgroups failed", ngroups_max);
+ ssize_t gidlist_nr;
+ if ((gidlist_nr = getgroups(ngroups_max, gidlist.get())) < 0)
+ return _error->Errno("getgroups", "Could not get new groups (%lu)", ngroups_max);
+ for (ssize_t i = 0; i < gidlist_nr; ++i)
+ if (gidlist[i] != pw->pw_gid)
+ return _error->Error("Could not switch group, user %s is still in group %d", toUser.c_str(), gidlist[i]);
+ }
+
+ // enabled by default as all fakeroot-lookalikes should fake that accordingly
+ if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::IDs", true) == true)
+ {
+ // 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
+ }
+
+ // disabled as fakeroot doesn't forbid (by design) (re)gaining root from unprivileged
+ if (VerifySandboxing == true || _config->FindB("APT::Sandbox::Verify::Regain", false) == true)
+ {
+ // 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;
+}
+ /*}}}*/
projects / apt.git / blobdiff