Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932737AbcDKNim (ORCPT ); Mon, 11 Apr 2016 09:38:42 -0400 Received: from mx2.suse.de ([195.135.220.15]:37494 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932536AbcDKNYO (ORCPT ); Mon, 11 Apr 2016 09:24:14 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Peter Hurley , Jiri Slaby Subject: [PATCH 3.12 65/98] net: irda: Fix use-after-free in irtty_open() Date: Mon, 11 Apr 2016 15:23:07 +0200 Message-Id: <6ac8c9ad25835cb971268f1e6ad0c6440ef076a8.1460380917.git.jslaby@suse.cz> X-Mailer: git-send-email 2.8.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2679 Lines: 67 From: Peter Hurley 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 401879c57f01cbf2da204ad2e8db910525c6dbea upstream. The N_IRDA line discipline may access the previous line discipline's closed and already-fre private data on open [1]. The tty->disc_data field _never_ refers to valid data on entry to the line discipline's open() method. Rather, the ldisc is expected to initialize that field for its own use for the lifetime of the instance (ie. from open() to close() only). [1] ================================================================== BUG: KASAN: use-after-free in irtty_open+0x422/0x550 at addr ffff8800331dd068 Read of size 4 by task a.out/13960 ============================================================================= BUG kmalloc-512 (Tainted: G B ): kasan: bad access detected ----------------------------------------------------------------------------- ... Call Trace: [] __asan_report_load4_noabort+0x3e/0x40 mm/kasan/report.c:279 [] irtty_open+0x422/0x550 drivers/net/irda/irtty-sir.c:436 [] tty_ldisc_open.isra.2+0x60/0xa0 drivers/tty/tty_ldisc.c:447 [] tty_set_ldisc+0x1a0/0x940 drivers/tty/tty_ldisc.c:567 [< inline >] tiocsetd drivers/tty/tty_io.c:2650 [] tty_ioctl+0xace/0x1fd0 drivers/tty/tty_io.c:2883 [< inline >] vfs_ioctl fs/ioctl.c:43 [] do_vfs_ioctl+0x57c/0xe60 fs/ioctl.c:607 [< inline >] SYSC_ioctl fs/ioctl.c:622 [] SyS_ioctl+0x74/0x80 fs/ioctl.c:613 [] entry_SYSCALL_64_fastpath+0x16/0x7a Reported-and-tested-by: Dmitry Vyukov Signed-off-by: Peter Hurley Signed-off-by: Jiri Slaby --- drivers/net/irda/irtty-sir.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/drivers/net/irda/irtty-sir.c b/drivers/net/irda/irtty-sir.c index 177441afeb96..aef74c69a661 100644 --- a/drivers/net/irda/irtty-sir.c +++ b/drivers/net/irda/irtty-sir.c @@ -430,16 +430,6 @@ static int irtty_open(struct tty_struct *tty) /* Module stuff handled via irda_ldisc.owner - Jean II */ - /* First make sure we're not already connected. */ - if (tty->disc_data != NULL) { - priv = tty->disc_data; - if (priv && priv->magic == IRTTY_MAGIC) { - ret = -EEXIST; - goto out; - } - tty->disc_data = NULL; /* ### */ - } - /* stop the underlying driver */ irtty_stop_receiver(tty, TRUE); if (tty->ops->stop) -- 2.8.1