1 files changed, 79 insertions, 0 deletions
diff --git a/libmisc/chowntty.c b/libmisc/chowntty.c
new file mode 100644
index 0000000..8043d8c
--- /dev/null
+++ b/libmisc/chowntty.c
@@ -0,0 +1,79 @@
+/*
+ * SPDX-FileCopyrightText: 1989 - 1994, Julianne Frances Haugh
+ * SPDX-FileCopyrightText: 1996 - 2001, Marek Michałkiewicz
+ * SPDX-FileCopyrightText: 2003 - 2005, Tomasz Kłoczko
+ * SPDX-FileCopyrightText: 2007 - 2009, Nicolas François
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <config.h>
+
+#ident "$Id$"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <errno.h>
+#include <grp.h>
+#include "prototypes.h"
+#include "defines.h"
+#include <pwd.h>
+#include "getdef.h"
+#include "shadowlog.h"
+
+/*
+ *	chown_tty() sets the login tty to be owned by the new user ID
+ *	with TTYPERM modes
+ */
+
+void chown_tty (const struct passwd *info)
+{
+	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.
+	 */
+
+	grent = getgr_nam_gid (getdef_str ("TTYGROUP"));
+	if (NULL != grent) {
+		gid = grent->gr_gid;
+		gr_free (grent);
+	} else {
+		gid = info->pw_gid;
+	}
+
+	/*
+	 * Change the permissions on the TTY to be owned by the user with
+	 * the group as determined above.
+	 */
+
+	if (   (fchown (STDIN_FILENO, info->pw_uid, gid) != 0)
+	    || (fchmod (STDIN_FILENO, (mode_t)getdef_num ("TTYPERM", 0600)) != 0)) {
+		int err = errno;
+		FILE *shadow_logfd = log_get_logfd();
+
+		fprintf (shadow_logfd,
+		         _("Unable to change owner or mode of tty stdin: %s"),
+		         strerror (err));
+		SYSLOG ((LOG_WARN,
+		         "unable to change owner or mode of tty stdin for user `%s': %s\n",
+		         info->pw_name, strerror (err)));
+		if (EROFS != err) {
+			closelog ();
+			exit (EXIT_FAILURE);
+		}
+	}
+#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
+}
+