[rsh] rlogind: don't call forkpty()

[Michal Sekletar]

commit 3c095f9e2ad63c6026f213bc1d0261ae1e2669e4
Author: Michal Sekletar <msekleta at redhat.com>
Date:   Thu Apr 11 14:38:27 2013 +0200

    rlogind: don't call forkpty()
    
    We can no longer call forkpty (a convenience routine that combines
    openpty, fork, and login_tty) because, with forkpty, the slave end of
    the pty is open only in the child process. The child process execs
    /bin/login which now closes all open file descriptors before doing
    a vhangup (see lkml.org/lkml/2012/6/5/145), and this resets packet
    mode on the pty, undoing the effect of the ioctl(master, TIOCPKT,
    &on) call made by the parent.
    
    Instead, we call openpty, fork, and login_tty individually, so
    that we can keep a file descriptor to the slave open in the parent
    process, thereby retaining packet mode even when the child closes
    file descriptors to call vhangup.
    
    Patch contributed by Philip Spencer, <pspencer at fields.utoronto.ca>.
    
    Resolves RHBZ #947213.
    
    Signed-off-by: Michal Sekletar <msekleta at redhat.com>

 netkit-rsh-0.17-rh947213.patch |   65 ++++++++++++++++++++++++++++++++++++++++
 rsh.spec                       |    2 +
 2 files changed, 67 insertions(+), 0 deletions(-)
---
diff --git a/netkit-rsh-0.17-rh947213.patch b/netkit-rsh-0.17-rh947213.patch
new file mode 100644
index 0000000..155f873
--- /dev/null
+++ b/netkit-rsh-0.17-rh947213.patch
@@ -0,0 +1,65 @@
+diff -up netkit-rsh-0.17/rlogind/rlogind.c.rh947213 netkit-rsh-0.17/rlogind/rlogind.c
+--- netkit-rsh-0.17/rlogind/rlogind.c.rh947213	2013-04-11 14:18:47.481715853 +0200
++++ netkit-rsh-0.17/rlogind/rlogind.c	2013-04-11 14:32:50.807780164 +0200
+@@ -67,12 +67,13 @@ char rcsid[] =
+ #include <unistd.h>
+ #include <stdlib.h>
+ #include <string.h>
++#include <pty.h>
++#include <utmp.h>
+ 
+ #include "pathnames.h"
+ #include "logwtmp.h"
+ #include "rlogind.h"
+ 
+-pid_t forkpty(int *, char *, struct termios *, struct winsize *);
+ int logout(const char *);
+ 
+ #ifndef TIOCPKT_WINDOW
+@@ -389,7 +390,7 @@ static void getstr(char *buf, int cnt, c
+ }
+ 
+ static void doit(int netfd) {
+-    int master, pid, on = 1;
++    int master, slave, r, pid, on = 1;
+     int authenticated = 0;
+     char *hname;
+     int hostok;
+@@ -421,12 +422,34 @@ static void doit(int netfd) {
+ 	write(netfd, "rlogind: Host address mismatch.\r\n", 33);
+     }
+ 
+-    pid = forkpty(&master, line, NULL, &win);
+-    if (pid < 0) {
++    /*  We can no longer call forkpty here (a convenience routine that combines
++        openpty, fork, and login_tty) because, with forkpty, the slave end of
++        the pty is open only in the child process. The child process execs
++        /bin/login which now closes all open file descriptors before doing a
++        vhangup (see lkml.org/lkml/2012/6/5/145), and this resets packet mode
++        on the pty, undoing the effect of the ioctl(master, TIOCPKT, &on) call
++        made by the parent.
++
++        Instead, we call openpty, fork, and login_tty individually, so that we
++        can keep a file descriptor to the slave open in the parent process,
++        thereby retaining packet mode even when the child closes file descriptors
++        to call vhangup. */
++    r = openpty(&master, &slave, line, NULL, &win);
++    if (r < 0) {
+ 	if (errno == ENOENT) fatal(netfd, "Out of ptys", 0);
+-	fatal(netfd, "Forkpty", 1);
++	fatal(netfd, "Openpty", 1);
++    }
++
++    signal(SIGHUP, SIG_IGN);
++
++    pid = fork();
++    if (pid < 0) {
++        fatal(netfd, "Fork", 1);
+     }
++
+     if (pid == 0) {
++	close(master);
++	login_tty(slave);
+ 	/* netfd should always be 0, but... */ 
+ 	if (netfd > 2) close(netfd);
+ 	child(hname, termtype, lusername, authenticated, rusername);
diff --git a/rsh.spec b/rsh.spec
index 3e8f8ba..82ff227 100644
--- a/rsh.spec
+++ b/rsh.spec
@@ -82,6 +82,7 @@ Patch41: netkit-rsh-0.17-rh650119.patch
 Patch42: netkit-rsh-0.17-rh710987.patch
 Patch43: netkit-rsh-0.17-rh784467.patch
 Patch44: netkit-rsh-0.17-rh896583.patch
+Patch45: netkit-rsh-0.17-rh947213.patch
 
 %description
 The rsh package contains a set of programs which allow users to run
@@ -154,6 +155,7 @@ from other machines
 %patch42 -p1 -b .rh710987
 %patch43 -p1 -b .rh784467
 %patch44 -b .rh896583
+%patch45 -p1 -b .rh947213
 
 # No, I don't know what this is doing in the tarball.
 rm -f rexec/rexec