[svn-upgrade] Integrating new upstream version, shadow (19990709)

libmisc/chowntty.c

@@ -0,0 +1,127 @@
+/*
+ * Copyright 1989 - 1994, Julianne Frances Haugh
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of Julianne F. Haugh nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <config.h>
+
+#include "rcsid.h"
+RCSID("$Id: chowntty.c,v 1.7 1998/12/28 20:34:43 marekm Exp $")
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdio.h>
+#include <grp.h>
+
+#include "prototypes.h"
+#include "defines.h"
+#include <pwd.h>
+#include "getdef.h"
+
+/*
+ * is_my_tty -- determine if "tty" is the same as TTY stdin is using
+ */
+
+static int
+is_my_tty(const char *tty)
+{
+	struct	stat	by_name, by_fd;
+
+	if (stat (tty, &by_name) || fstat (0, &by_fd))
+		return 0;
+
+	if (by_name.st_rdev != by_fd.st_rdev)
+		return 0;
+	else
+		return 1;
+}
+
+/*
+ *	chown_tty() sets the login tty to be owned by the new user ID
+ *	with TTYPERM modes
+ */
+
+void
+chown_tty(const char *tty, const struct passwd *info)
+{
+	char buf[200], full_tty[200];
+	char	*group;		/* TTY group name or number */
+	struct	group	*grent;
+	gid_t gid;
+
+	/*
+	 * See if login.defs has some value configured for the port group
+	 * ID.  Otherwise, use the user's primary group ID.
+	 */
+
+	if (! (group = getdef_str ("TTYGROUP")))
+		gid = info->pw_gid;
+	else if (group[0] >= '0' && group[0] <= '9')
+		gid = atoi (group);
+	else if ((grent = getgrnam (group)))
+		gid = grent->gr_gid;
+	else
+		gid = info->pw_gid;
+
+	/*
+	 * Change the permissions on the TTY to be owned by the user with
+	 * the group as determined above.
+	 */
+
+	if (*tty != '/') {
+		snprintf(full_tty, sizeof full_tty, "/dev/%s", tty);
+		tty = full_tty;
+	}
+
+	if (! is_my_tty (tty)) {
+		SYSLOG((LOG_WARN, "unable to determine TTY name, got %s\n",
+			tty));
+		closelog();
+		exit (1);
+	}
+	
+	if (chown(tty, info->pw_uid, gid) ||
+			chmod(tty, getdef_num("TTYPERM", 0600))) {
+		snprintf(buf, sizeof buf, _("Unable to change tty %s"), tty);
+		SYSLOG((LOG_WARN, "unable to change tty `%s' for user `%s'\n",
+			tty, info->pw_name));
+		closelog();
+		perror (buf);
+		exit(1);
+	}
+
+#ifdef __linux__
+	/*
+	 * Please don't add code to chown /dev/vcs* to the user logging in -
+	 * it's a potential security hole.  I wouldn't like the previous user
+	 * to hold the file descriptor open and watch my screen.  We don't
+	 * have the *BSD revoke() system call yet, and vhangup() only works
+	 * for tty devices (which vcs* is not).  --marekm
+	 */
+#endif
+}