kpty: assume grantpt() and unlockpt() are available

Signed-off-by: Ivailo Monev <xakepa10@gmail.com>

ConfigureChecks.cmake

@@ -119,8 +119,6 @@ if (UNIX)
     set(HAVE_OPENPTY 0)
 
     check_function_exists(revoke     HAVE_REVOKE)
-    check_function_exists(grantpt    HAVE_GRANTPT)
-    check_function_exists(unlockpt   HAVE_UNLOCKPT)
   endif (openpty_in_libc OR openpty_in_libutil)
 
   check_function_exists(ptsname_r  HAVE_PTSNAME_R)

config-pty.h.cmake

@@ -2,11 +2,9 @@
 #cmakedefine PTM_DEVICE "${PTM_DEVICE}"
 
 #cmakedefine HAVE_LIBUTIL_H 1
-#cmakedefine HAVE_GRANTPT 1
 #cmakedefine HAVE_OPENPTY 1
 #cmakedefine HAVE_PTSNAME_R 1
 #cmakedefine HAVE_REVOKE 1
-#cmakedefine HAVE_UNLOCKPT 1
 
 #cmakedefine HAVE_PTY_H 1
 #cmakedefine HAVE_TERMIO_H 1

kpty/CMakeLists.txt

@@ -42,12 +42,6 @@ install(
 
 ########### next target ###############
 
-if(NOT HAVE_OPENPTY)
-    add_executable(kgrantpty kgrantpty.c)
-    target_link_libraries(kgrantpty)
-    install(TARGETS kgrantpty DESTINATION ${KDE4_LIBEXEC_INSTALL_DIR})
-endif()
-
 if(ENABLE_TESTING)
     add_subdirectory(tests)
 endif()

kpty/kgrantpty.c

@@ -1,180 +0,0 @@
-/* kgrantpty - helper program for KPty. */
-
-/* This program is based on the glibc2.1 pt_chmod.
- * It was pulled out from there since both Linux
- * distributors and other OSes are not able to make
- * use of the glibc for different reasons.
- *
- * THIS IS A ROOT SUID PROGRAM
- *
- * Things work as following:
- *
- * In konsole we open a master pty. This can be opened
- * done by at most one process. Prior to opening the
- * master pty, the slave pty cannot be opened. Then, in
- * grantpty, we fork to this program. The trick is, that
- * the parameter is passes as a file handle, which cannot
- * be faked, so that we get a secure setuid root chmod/chown
- * with this program.
- *
- * We have to chown/chmod the slave pty to prevent eavesdroping.
- *
- * Contributed by Zack Weinberg <zack@rabi.phys.columbia.edu>, 1998.
- * Copyright (c) 1999 by Lars Doelle <lars.doelle@on-line.de>.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor,
- * Boston, MA  02110-1301, USA
- */
-
-#include <config.h>
-#include <config-pty.h>
-
-#include <sys/types.h>
-#include <errno.h>
-#include <grp.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/ioctl.h>
-#include <sys/param.h>
-#include <unistd.h>
-
-#ifdef HAVE_PTY_H
-#  include <pty.h>
-#endif
-
-
-#define TTY_GROUP "tty"
-
-int main (int argc, char *argv[])
-{
-  struct stat   st;
-  gid_t         gid;
-  uid_t         uid;
-  mode_t        mod;
-  char*         tty = 0;
-  int           fd;
-#if defined(HAVE_PTSNAME_R)
-  char          ttyb[32];
-#endif
-
-  /* check preconditions **************************************************/
-  if (argc != 3 || (strcmp(argv[1],"--grant") && strcmp(argv[1],"--revoke")))
-  {
-    printf("usage: %s (--grant|--revoke) <file descriptor>\n"
-           "%s is a helper for the KDE core libraries.\n"
-           "It is not intended to be called from the command line.\n"
-           "It needs to be installed setuid root to function.\n",
-           argv[0], argv[0]);
-    return 1; /* FAIL */
-  }
-
-  if (geteuid () != 0)
-  {
-    fprintf(stderr, "%s not installed setuid root\n", argv[0]);
-    return 1; /* FAIL */
-  }
-
-  fd = atoi(argv[2]);
-
-  /* get slave pty name from master pty file handle *********/
-#if defined(HAVE_PTSNAME_R)
-  memset(ttyb, '\0', sizeof(ttyb) * sizeof(char));
-  if (ptsname_r(fd, ttyb, sizeof(ttyb)) == 0) {
-     tty = ttyb;
-  if (!tty)
-#else
-  tty = ptsname(fd);
-  if (!tty)
-#endif
-  {
-    /* Check that fd is a valid master pseudo terminal.  */
-#if defined(HAVE_TTYNAME_R)
-    char pty[32];
-    memset(pty, '\0', sizeof(pty) * sizeof(char));
-    if (ttyname_r(fd, pty, sizeof(pty)) != 0)
-#else
-    char *pty = ttyname(fd);
-    if (pty == NULL)
-#endif
-    {
-      fprintf(stderr,"%s: cannot determine pty name.\n",argv[0]);
-      return 1; /* FAIL */
-    }
-
-    /* matches /dev/pty?? */
-    if (memcmp(pty,"/dev/pty",8))
-    {
-      fprintf(stderr,"%s: determined a strange pty name '%s'.\n",argv[0],pty);
-#if !defined(HAVE_TTYNAME_R)
-      free(pty);
-#endif
-      return 1; /* FAIL */
-    }
-
-    tty = malloc(strlen(pty) + 1);
-    strcpy(tty,"/dev/tty");
-    strcat(tty,pty+8);
-#if !defined(HAVE_TTYNAME_R)
-    free(pty);
-#endif
-  }
-
-  /* Check that the returned slave pseudo terminal is a character device.  */
-  if (stat(tty, &st) < 0 || !S_ISCHR(st.st_mode))
-  {
-    fprintf(stderr,"%s: found '%s' not to be a character device.\n",argv[0],tty);
-    free(tty);
-    return 1; /* FAIL */
-  }
-
-  /* setup parameters for the operation ***********************************/
-
-  if (!strcmp(argv[1],"--grant"))
-  {
-    uid = getuid();
-    struct group* p = getgrnam(TTY_GROUP);
-    if (!p)
-      p = getgrnam("wheel");
-    gid = p ? p->gr_gid : getgid ();
-    mod = S_IRUSR | S_IWUSR | S_IWGRP;
-  }
-  else
-  {
-    uid = 0;
-    gid = st.st_gid == getgid () ? 0 : -1;
-    mod = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
-  }
-
-  /* Perform the actual chown/chmod ************************************/
-
-  if (chown(tty, uid, gid) < 0)
-  {
-    fprintf(stderr,"%s: cannot chown %s: %s\n",argv[0],tty,strerror(errno));
-    free(tty);
-    return 1; /* FAIL */
-  }
-
-  if (chmod(tty, mod) < 0)
-  {
-    fprintf(stderr,"%s: cannot chmod %s: %s\n",argv[0],tty,strerror(errno));
-    free(tty);
-    return 1; /* FAIL */
-  }
-
-  free(tty);
-  return 0; /* OK */
-}

kpty/kpty.cpp

@@ -80,13 +80,8 @@ extern "C" {
 #endif
 
 #include <kdebug.h>
-#include <kstandarddirs.h>	// findExe
 #include <kde_file.h>
 
-#include <QtCore/qprocess.h>
-
-#define TTY_GROUP "tty"
-
 #ifndef PATH_MAX
 # define PATH_MAX _POSIX_PATH_MAX
 #endif
@@ -108,14 +103,6 @@ KPtyPrivate::~KPtyPrivate()
 {
 }
 
-#ifndef HAVE_OPENPTY
-bool KPtyPrivate::chownpty(bool grant)
-{
-    return !QProcess::execute(KStandardDirs::findExe("kgrantpty"),
-        QStringList() << (grant?"--grant":"--revoke") << QString::number(masterFd));
-}
-#endif
-
 /////////////////////////////
 // public member functions //
 /////////////////////////////
@@ -176,97 +163,29 @@ bool KPty::open()
 #ifdef HAVE_PTSNAME_R
     char ptsn[32];
     ::memset(ptsn, '\0', sizeof(ptsn) * sizeof(char));
-    if (ptsname_r(d->masterFd, ptsn, sizeof(ptsn)) == 0) {
+    if (::ptsname_r(d->masterFd, ptsn, sizeof(ptsn)) == 0) {
         d->ttyName = ptsn;
 #else // HAVE_PTSNAME_R
-    char *ptsn = ptsname(d->masterFd);
+    char *ptsn = ::ptsname(d->masterFd);
     if (ptsn) {
         d->ttyName = ptsn;
 #endif // HAVE_PTSNAME_R
-#ifdef HAVE_GRANTPT
+        if (::grantpt(d->masterFd) == 0)
-        if (!grantpt(d->masterFd))
            goto grantedpt;
-#else // HAVE_GRANTPT
-        goto gotpty;
-#endif // HAVE_GRANTPT
     }
     ::close(d->masterFd);
     d->masterFd = -1;
   }
 
-  // Linux device names, FIXME: Trouble on other systems?
-  for (const char* s3 = "pqrstuvwxyzabcde"; *s3; s3++)
-  {
-    for (const char* s4 = "0123456789abcdef"; *s4; s4++)
-    {
-      ptyName = QString().sprintf("/dev/pty%c%c", *s3, *s4).toLatin1();
-      d->ttyName = QString().sprintf("/dev/tty%c%c", *s3, *s4).toLatin1();
-
-      d->masterFd = KDE_open(ptyName.data(), O_RDWR);
-      if (d->masterFd >= 0)
-      {
-#ifdef Q_OS_SOLARIS
-        /* Need to check the process group of the pty.
-         * If it exists, then the slave pty is in use,
-         * and we need to get another one.
-         */
-        int pgrp_rtn;
-        if (ioctl(d->masterFd, TIOCGPGRP, &pgrp_rtn) == 0 || errno != EIO) {
-          ::close(d->masterFd);
-          d->masterFd = -1;
-          continue;
-        }
-#endif /// Q_OS_SOLARIS
-        if (!access(d->ttyName.data(),R_OK|W_OK)) // checks availability based on permission bits
-        {
-          if (!geteuid())
-          {
-            struct group* p = getgrnam(TTY_GROUP);
-            if (!p)
-              p = getgrnam("wheel");
-            gid_t gid = p ? p->gr_gid : getgid ();
-
-            chown(d->ttyName.data(), getuid(), gid);
-            chmod(d->ttyName.data(), S_IRUSR|S_IWUSR|S_IWGRP);
-          }
-          goto gotpty;
-        }
-        ::close(d->masterFd);
-        d->masterFd = -1;
-      }
-    }
-  }
-
   kWarning(175) << "Can't open a pseudo teletype";
   return false;
 
- gotpty:
-  KDE_struct_stat st;
-  if (KDE_stat(d->ttyName.data(), &st))
-    return false; // this just cannot happen ... *cough*  Yeah right, I just
-                  // had it happen when pty #349 was allocated.  I guess
-                  // there was some sort of leak?  I only had a few open.
-  if (((st.st_uid != getuid()) ||
-       (st.st_mode & (S_IRGRP|S_IXGRP|S_IROTH|S_IWOTH|S_IXOTH))) &&
-      !d->chownpty(true))
-  {
-    kWarning(175)
-      << "chownpty failed for device " << ptyName << "::" << d->ttyName
-      << "\nThis means the communication can be eavesdropped." << endl;
-  }
-
  grantedpt:
-
 #ifdef HAVE_REVOKE
   revoke(d->ttyName.data());
 #endif
 
-#ifdef HAVE_UNLOCKPT
   unlockpt(d->masterFd);
-#elif defined(TIOCSPTLCK)
-  int flag = 0;
-  ioctl(d->masterFd, TIOCSPTLCK, &flag);
-#endif
 
   d->slaveFd = KDE_open(d->ttyName.data(), O_RDWR | O_NOCTTY);
   if (d->slaveFd < 0)
@@ -375,15 +294,14 @@ void KPty::close()
 #ifndef HAVE_OPENPTY
         // don't bother resetting unix98 pty, it will go away after closing master anyway.
         if (memcmp(d->ttyName.data(), "/dev/pts/", 9)) {
-            if (!geteuid()) {
+            if (geteuid() == 0) {
                 KDE_struct_stat st;
-                if (!KDE_stat(d->ttyName.data(), &st)) {
+                if (KDE_stat(d->ttyName.data(), &st) == 0) {
                     chown(d->ttyName.data(), 0, st.st_gid == getgid() ? 0 : -1);
                     chmod(d->ttyName.data(), S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
                 }
             } else {
                 fcntl(d->masterFd, F_SETFD, 0);
-                d->chownpty(false);
             }
         }
 #endif

kpty/kpty_p.h

@@ -33,9 +33,6 @@ class KPtyPrivate {
 public:
     KPtyPrivate(KPty* parent);
     virtual ~KPtyPrivate();
-#ifndef HAVE_OPENPTY
-    bool chownpty(bool grant);
-#endif
 
     int masterFd;
     int slaveFd;