upstream commit

fix use-after-free in ~^Z escape handler path, introduced
in channels.c refactor; spotted by millert@ "makes sense" deraadt@

Upstream-ID: 8fa2cdc65c23ad6420c1e59444b0c955b0589b22

1 files changed, 4 insertions, 13 deletions

diff --git a/clientloop.c b/clientloop.c
index 3b4840b12..791d336e3 100644
--- a/clientloop.c
+++ b/clientloop.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: clientloop.c,v 1.304 2017/09/12 06:35:32 djm Exp $ */
+/* $OpenBSD: clientloop.c,v 1.305 2017/09/19 04:24:22 djm Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -600,13 +600,9 @@ client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
 
         leave_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 
-        /*
-         * Free (and clear) the buffer to reduce the amount of data that gets
-         * written to swap.
-         */
-        buffer_free(bin);
-        buffer_free(bout);
-        buffer_free(berr);
+        sshbuf_reset(bin);
+        sshbuf_reset(bout);
+        sshbuf_reset(berr);
 
         /* Send the suspend signal to the program itself. */
         kill(getpid(), SIGTSTP);
@@ -614,11 +610,6 @@ client_suspend_self(Buffer *bin, Buffer *bout, Buffer *berr)
         /* Reset window sizes in case they have changed */
         received_window_change_signal = 1;
 
-        /* OK, we have been continued by the user. Reinitialize buffers. */
-        buffer_init(bin);
-        buffer_init(bout);
-        buffer_init(berr);
-
         enter_raw_mode(options.request_tty == REQUEST_TTY_FORCE);
 }