linux-kernel - [PATCH] net: irda: Fix use-after-free in irtty

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1448652170-4337-1-git-send-email-peter@hurleysoftware.com>
Date:	Fri, 27 Nov 2015 14:22:50 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Jiri Slaby <jslaby@...e.cz>, linux-kernel@...r.kernel.org,
	David Miller <davem@...emloft.net>,
	Samuel Ortiz <samuel@...tiz.org>,
	Dmitry Vyukov <dvyukov@...gle.com>,
	Peter Hurley <peter@...leysoftware.com>, stable@...r.kernel.org
Subject: [PATCH] net: irda: Fix use-after-free in irtty_open()

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:
     [<ffffffff815fa2ae>] __asan_report_load4_noabort+0x3e/0x40 mm/kasan/report.c:279
     [<ffffffff836938a2>] irtty_open+0x422/0x550 drivers/net/irda/irtty-sir.c:436
     [<ffffffff829f1b80>] tty_ldisc_open.isra.2+0x60/0xa0 drivers/tty/tty_ldisc.c:447
     [<ffffffff829f21c0>] tty_set_ldisc+0x1a0/0x940 drivers/tty/tty_ldisc.c:567
     [<     inline     >] tiocsetd drivers/tty/tty_io.c:2650
     [<ffffffff829da49e>] tty_ioctl+0xace/0x1fd0 drivers/tty/tty_io.c:2883
     [<     inline     >] vfs_ioctl fs/ioctl.c:43
     [<ffffffff816708ac>] do_vfs_ioctl+0x57c/0xe60 fs/ioctl.c:607
     [<     inline     >] SYSC_ioctl fs/ioctl.c:622
     [<ffffffff81671204>] SyS_ioctl+0x74/0x80 fs/ioctl.c:613
     [<ffffffff852a7876>] entry_SYSCALL_64_fastpath+0x16/0x7a

Reported-and-tested-by: Dmitry Vyukov <dvyukov@...gle.com>
Cc: <stable@...r.kernel.org>
Signed-off-by: Peter Hurley <peter@...leysoftware.com>
---
 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 696852e..7a3f990 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)
-- 
2.6.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/