Consider md5sum no longer a usable hash

[apt.git] / apt-pkg / contrib / fileutl.cc

diff --git a/apt-pkg/contrib/fileutl.cc b/apt-pkg/contrib/fileutl.cc
index a6af27b0092f8a19a3d5c9f1f4206faf84b315ef..837edef4b1e015a075549c5cccbc672c7c3149c3 100644 (file)
--- a/apt-pkg/contrib/fileutl.cc
+++ b/apt-pkg/contrib/fileutl.cc
@@ -2006,12 +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) {
@@ -2122,12 +2123,39 @@ std::string GetTempDir()                                                /*{{{*/
 
    struct stat st;
    if (!tmpdir || strlen(tmpdir) == 0 || // tmpdir is set
-        stat(tmpdir, &st) != 0 || (st.st_mode & S_IFDIR) == 0 || // exists and is directory
-        access(tmpdir, R_OK | W_OK | X_OK) != 0 // current user has rwx access to directory
-      )
+        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 * const TmpFd)     /*{{{*/
@@ -2252,22 +2280,32 @@ bool DropPrivileges()                                                   /*{{{*/
       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];