Reset displays before dumping a core.

If defined SHADOWPW, we may have passwd records in core, that the user
would not be able to access otherwise. In that case, we should not dump
core, as the core file would contain the passwd records, and would be
readable for the user.
We do not explicitly check for eff_uid == 0, because if his real_uid is
also 0 he could have read all this anyway. Leaving only the cases where the
two uids differ.

1 files changed, 35 insertions, 21 deletions

diff --git a/src/screen.c b/src/screen.c
index 67cddbc..06441dd 100644
--- a/src/screen.c
+++ b/src/screen.c
@@ -1,4 +1,7 @@
-/* Copyright (c) 2008, 2009
+/* Copyright (c) 2010
+ *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ *      Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
+ * Copyright (c) 2008, 2009
  *      Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
  *      Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
  *      Micah Cowan (micah@cowan.name)
@@ -764,17 +767,12 @@ char **av;
   real_gid = getgid();
   eff_uid = geteuid();
   eff_gid = getegid();
-  if (eff_uid != real_uid)
-    {
-      /* if running with s-bit, we must install a special signal
-       * handler routine that resets the s-bit, so that we get a
-       * core file anyway.
-       */
+
 #ifdef SIGBUS /* OOPS, linux has no bus errors! */
-      signal(SIGBUS, CoreDump);
+  signal(SIGBUS, CoreDump);
 #endif /* SIGBUS */
-      signal(SIGSEGV, CoreDump);
-    }
+  signal(SIGSEGV, CoreDump);
+
 
 #ifdef USE_LOCALE
   setlocale(LC_ALL, "");
@@ -1636,39 +1634,55 @@ SigInt SIGDEFARG
 static sigret_t
 CoreDump SIGDEFARG
 {
+  /* if running with s-bit, we must reset the s-bit, so that we get a
+   * core file anyway.
+   */
+
   struct display *disp;
   char buf[80];
 
+  char *dump_msg = " (core dumped)";
+
+  int running_w_s_bit = getuid() != geteuid();
+#if defined(SHADOWPW) && !defined(DEBUG) && !defined(DUMPSHADOW)
+  if (running_w_s_bit)
+    dump_msg = "";
+#endif
+
 #if defined(SYSVSIGS) && defined(SIGHASARG)
   signal(sigsig, SIG_IGN);
 #endif
   setgid(getgid());
   setuid(getuid());
   unlink("core");
+
 #ifdef SIGHASARG
-  sprintf(buf, "\r\n[screen caught signal %d.%s]\r\n", sigsig,
+  sprintf(buf, "\r\n[screen caught signal %d.%s]\r\n", sigsig, dump_msg);
 #else
-  sprintf(buf, "\r\n[screen caught a fatal signal.%s]\r\n",
+  sprintf(buf, "\r\n[screen caught a fatal signal.%s]\r\n", dump_msg);
 #endif
-#if defined(SHADOWPW) && !defined(DEBUG) && !defined(DUMPSHADOW)
-              ""
-#else /* SHADOWPW  && !DEBUG */
-              " (core dumped)"
-#endif /* SHADOWPW  && !DEBUG */
-              );
+
   for (disp = displays; disp; disp = disp->d_next)
     {
+      if (disp->d_nonblock < -1 || disp->d_nonblock > 1000000)
+	continue;
       fcntl(disp->d_userfd, F_SETFL, 0);
       SetTTY(disp->d_userfd, &D_OldMode);
       write(disp->d_userfd, buf, strlen(buf));
       Kill(disp->d_userpid, SIG_BYE);
     }
+
+  if (running_w_s_bit)
+    {
 #if defined(SHADOWPW) && !defined(DEBUG) && !defined(DUMPSHADOW)
-  Kill(getpid(), SIGKILL);
-  eexit(11);
+      Kill(getpid(), SIGKILL);
+      eexit(11);
 #else /* SHADOWPW && !DEBUG */
-  abort();
+      abort();
 #endif /* SHADOWPW  && !DEBUG */
+    }
+  else
+    abort();
   SIGRETURN;
 }