linux-kernel - [PATCH 4.14 124/126] tuntap: fix use after free during release

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

Message-Id: <20180917211712.100481625@linuxfoundation.org>
Date:   Tue, 18 Sep 2018 00:42:52 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Andrei Vagin <avagin@...tuozzo.com>,
        Jason Wang <jasowang@...hat.com>,
        "David S. Miller" <davem@...emloft.net>,
        Zubin Mithra <zsm@...omium.org>
Subject: [PATCH 4.14 124/126] tuntap: fix use after free during release

4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@...hat.com>

commit 7063efd33bb15abc0160347f89eb5aba6b7d000e upstream.

After commit b196d88aba8a ("tun: fix use after free for ptr_ring") we
need clean up tx ring during release(). But unfortunately, it tries to
do the cleanup blindly after socket were destroyed which will lead
another use-after-free. Fix this by doing the cleanup before dropping
the last reference of the socket in __tun_detach().

Backport Note :-
Upstream commit moves the ptr_ring_cleanup call from tun_chr_close to
__tun_detach. Upstream applied that patch after replacing skb_array with
ptr_ring. This patch moves the skb_array_cleanup call from
tun_chr_close to __tun_detach.

Reported-by: Andrei Vagin <avagin@...tuozzo.com>
Acked-by: Andrei Vagin <avagin@...tuozzo.com>
Fixes: b196d88aba8a ("tun: fix use after free for ptr_ring")
Signed-off-by: Jason Wang <jasowang@...hat.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Zubin Mithra <zsm@...omium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/net/tun.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -575,6 +575,7 @@ static void __tun_detach(struct tun_file
 			    tun->dev->reg_state == NETREG_REGISTERED)
 				unregister_netdevice(tun->dev);
 		}
+		skb_array_cleanup(&tfile->tx_array);
 		sock_put(&tfile->sk);
 	}
 }
@@ -2646,7 +2647,6 @@ static int tun_chr_close(struct inode *i
 	struct tun_file *tfile = file->private_data;
 
 	tun_detach(tfile, true);
-	skb_array_cleanup(&tfile->tx_array);
 
 	return 0;
 }