From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756949Ab3J1Q0y (ORCPT ); Mon, 28 Oct 2013 12:26:54 -0400 Received: from mail-pd0-f177.google.com ([209.85.192.177]:39138 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756347Ab3J1Q0x (ORCPT ); Mon, 28 Oct 2013 12:26:53 -0400 Date: Tue, 29 Oct 2013 00:26:05 +0800 From: Wang YanQing To: gregkh@linuxfoundation.org Cc: rucsoftsec@gmail.com, jslaby@suse.cz, airlied@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH]tty:vt: Add NULL check to return value of kzalloc() Message-ID: <20131028162605.GA3738@udknight> Mail-Followup-To: Wang YanQing , gregkh@linuxfoundation.org, rucsoftsec@gmail.com, jslaby@suse.cz, airlied@redhat.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In extreme situation kzalloc in con_init may return NULL, so we should check it to prevent OOPS! Signed-off-by: Wang YanQing Reported-by: rucsoftsec@gmail.com --- I don't think a system without memory to initialize vt could do some useful things, but this patch could make debug easier and improve kernel code's robustness in theory. drivers/tty/vt/vc_screen.c | 2 +- drivers/tty/vt/vt.c | 12 ++++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c index 14a2b5f..2bc3987bc 100644 --- a/drivers/tty/vt/vc_screen.c +++ b/drivers/tty/vt/vc_screen.c @@ -648,6 +648,6 @@ int __init vcs_init(void) device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 0), NULL, "vcs"); device_create(vc_class, NULL, MKDEV(VCS_MAJOR, 128), NULL, "vcsa"); for (i = 0; i < MIN_NR_CONSOLES; i++) - vcs_make_sysfs(i); + if (vc_cons[i].d) vcs_make_sysfs(i); return 0; } diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c index 9a8e8c5..ef8b1aa 100644 --- a/drivers/tty/vt/vt.c +++ b/drivers/tty/vt/vt.c @@ -2887,6 +2887,8 @@ static int __init con_init(void) for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) { vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT); + if (vc == NULL) + break; INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK); tty_port_init(&vc->port); visual_init(vc, currcons, 1); @@ -2894,8 +2896,18 @@ static int __init con_init(void) vc_init(vc, vc->vc_rows, vc->vc_cols, currcons || !vc->vc_sw->con_save_screen); } + if (currcons < MIN_NR_CONSOLES) + printk(KERN_WARNING "Console: vt %d-%d initialization failed!\n", + currcons, MIN_NR_CONSOLES - 1); + currcons = fg_console = 0; master_display_fg = vc = vc_cons[currcons].d; + + if (vc == NULL) { + printk(KERN_WARNING "Console: no avaiable vt!\n"); + console_unlock(); + return 0; + } set_origin(vc); save_screen(vc); gotoxy(vc, vc->vc_x, vc->vc_y); -- 1.7.12.4.dirty