From: Karel Zak <kzak@redhat.com>
Date: Wed, 1 Feb 2017 10:58:09 +0000 (+0100)
Subject: su: properly clear child PID
X-Git-Tag: v2.29.2~17
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b018571132cb8c9fece3d75ed240cc74cdb5f0f7;p=thirdparty%2Futil-linux.git

su: properly clear child PID

Reported-by: Tobias Stöckmann <tobias@stoeckmann.org>
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index 0ea4e40bd0..b1720f037f 100644
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -376,6 +376,9 @@ create_watching_parent (void)
             }
           else
             status = WEXITSTATUS (status);
+
+	  /* child is gone, don't use the PID anymore */
+	  child = (pid_t) -1;
         }
       else if (caught_signal)
         status = caught_signal + 128;
@@ -385,7 +388,7 @@ create_watching_parent (void)
   else
     status = 1;
 
-  if (caught_signal)
+  if (caught_signal && child != (pid_t)-1)
     {
       fprintf (stderr, _("\nSession terminated, killing shell..."));
       kill (child, SIGTERM);
@@ -395,9 +398,12 @@ create_watching_parent (void)
 
   if (caught_signal)
     {
-      sleep (2);
-      kill (child, SIGKILL);
-      fprintf (stderr, _(" ...killed.\n"));
+      if (child != (pid_t)-1)
+	{
+	  sleep (2);
+	  kill (child, SIGKILL);
+	  fprintf (stderr, _(" ...killed.\n"));
+	}
 
       /* Let's terminate itself with the received signal.
        *