From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DF84F746F for ; Sun, 17 Sep 2023 20:37:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A74FC433C7; Sun, 17 Sep 2023 20:37:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694983051; bh=muDtx0IPLQwvepeTe6y4RStc7A5tyrUojWhDuhDpv+w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HzCHm4DuBpp8cfy7X0pttgEk9NO5USOBds5MsiXkjCOXF7was7dLEqTAH+gbjPuZz IeKpoj4NDCjUVrIhBCfj4+WSay1nLAPbobl5x32zu8ZsSIFwinnykWyc58HaRIi70R bTqXXqSL64jpSGR3NyWCaMY+F4c3dkhnXy0LX06g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+822d1359297e2694f873@syzkaller.appspotmail.com, Magnus Karlsson , Daniel Borkmann , Maciej Fijalkowski , Sasha Levin Subject: [PATCH 5.15 431/511] xsk: Fix xsk_diag use-after-free error during socket cleanup Date: Sun, 17 Sep 2023 21:14:18 +0200 Message-ID: <20230917191124.174314960@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230917191113.831992765@linuxfoundation.org> References: <20230917191113.831992765@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Magnus Karlsson [ Upstream commit 3e019d8a05a38abb5c85d4f1e85fda964610aa14 ] Fix a use-after-free error that is possible if the xsk_diag interface is used after the socket has been unbound from the device. This can happen either due to the socket being closed or the device disappearing. In the early days of AF_XDP, the way we tested that a socket was not bound to a device was to simply check if the netdevice pointer in the xsk socket structure was NULL. Later, a better system was introduced by having an explicit state variable in the xsk socket struct. For example, the state of a socket that is on the way to being closed and has been unbound from the device is XSK_UNBOUND. The commit in the Fixes tag below deleted the old way of signalling that a socket is unbound, setting dev to NULL. This in the belief that all code using the old way had been exterminated. That was unfortunately not true as the xsk diagnostics code was still using the old way and thus does not work as intended when a socket is going down. Fix this by introducing a test against the state variable. If the socket is in the state XSK_UNBOUND, simply abort the diagnostic's netlink operation. Fixes: 18b1ab7aa76b ("xsk: Fix race at socket teardown") Reported-by: syzbot+822d1359297e2694f873@syzkaller.appspotmail.com Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Tested-by: syzbot+822d1359297e2694f873@syzkaller.appspotmail.com Tested-by: Maciej Fijalkowski Reviewed-by: Maciej Fijalkowski Link: https://lore.kernel.org/bpf/20230831100119.17408-1-magnus.karlsson@gmail.com Signed-off-by: Sasha Levin --- net/xdp/xsk_diag.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/xdp/xsk_diag.c b/net/xdp/xsk_diag.c index c014217f5fa7d..22b36c8143cfd 100644 --- a/net/xdp/xsk_diag.c +++ b/net/xdp/xsk_diag.c @@ -111,6 +111,9 @@ static int xsk_diag_fill(struct sock *sk, struct sk_buff *nlskb, sock_diag_save_cookie(sk, msg->xdiag_cookie); mutex_lock(&xs->mutex); + if (READ_ONCE(xs->state) == XSK_UNBOUND) + goto out_nlmsg_trim; + if ((req->xdiag_show & XDP_SHOW_INFO) && xsk_diag_put_info(xs, nlskb)) goto out_nlmsg_trim; -- 2.40.1