Ticket History #335: On systems with POSIX signals, rlogin doesn't clear them

From kenh@cmf.nrl.navy.mil Mon Jan 6 23:53:16 1997
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Date: Mon, 6 Jan 1997 23:53:13 -0500 (EST)
From: Ken Hornstein <kenh@cmf.nrl.navy.mil>
Reply-To: kenh@cmf.nrl.navy.mil
To: krb5-bugs@MIT.EDU
Subject: When using POSIX signals, rlogin doesn't clear them properly
X-Send-Pr-Version: 3.2

Naval Research Lab

System: SunOS nexus 4.1.4 1 sun4m
Architecture: sun4


Rlogin will try to run the regular Unix rlogin if the Kerberos one fails.
However, if your system supports POSIX signals, there is a subtle problem.

The Kerberos rlogin does not clear the signal mask before it tries running
the regular rlogin; as a result, some rlogins will not get SIGUSR1 during
startup and will not send the window size.

Run Kerberos rlogin on a system that supports POSIX signals (like NetBSD)
to host that doesn't support Kerberos. Note that your window size isn't
passed.

--- krlogin.c.orig Mon Jan 6 23:45:33 1997
+++ krlogin.c Mon Jan 6 23:46:53 1997
@@ -1570,6 +1570,10 @@
char **argv;
{
register char *host;
+#ifdef POSIX_SIGNALS
+ struct sigaction sa;
+ sigest_t mask;
+#endif

#ifndef KRB5_ATHENA_COMPAT
if (encrypt_flag)
@@ -1587,6 +1591,11 @@
if (!strcmp(host, "rlogin"))
argv++;

+#ifdef POSIX_SIGNALS
+ sigemptyset(&mask)
+ sigprocmask(SIG_SETMASK, &mask, NULL);
+#endif
+
execv(UCB_RLOGIN, argv);
perror("exec");
exit(1);

State-Changed-From-To: open-closed
State-Changed-By: tytso
State-Changed-When: Fri Mar 28 01:07:49 1997
State-Changed-Why: Patch applied to mainline