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 583A321E085; Thu, 12 Dec 2024 17:29:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734024562; cv=none; b=Z+7paNAg+j0LGTTsrXOw362OlTEgf5IUkbdX0ExWnn5iquLdzbDQfpPSdG/1RhxUzbx17XmqpM0WWIDhdhOhsn9rmqD5eHs95ByfKNZlcvucKXkxD+ejmO4winM+RJpjc9ZX/NBrvHGIeft6Z2vNJYHx8+7embRe+I+cvLt6lMU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734024562; c=relaxed/simple; bh=KwB/D6hOG986RsVf/V6TFsNHRO+YOfHIZeunxJKMKz8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TgHy4Vt8+fmZG/9xBIlVgu8sW+FLCkORkd9QD13b3zZTSHcf2qjLymiLfyLI4ko9C+qO3w2y20uYDSMS95nFYtTYY9PDrHN0McXs2k3qh8UmNYG/0wR/uhQNBBhsAUtpaTD29zYd4rdm40X+GlH9lLffAb3L6KHRkZOqxUubwKE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=for/88Na; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="for/88Na" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0005C4CED4; Thu, 12 Dec 2024 17:29:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1734024562; bh=KwB/D6hOG986RsVf/V6TFsNHRO+YOfHIZeunxJKMKz8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=for/88NaD50yQlPQoFQO/oUD8AsKkSkMdKEMBhghxgA+cswHAsibyEglfELpctaIL HaVhfckV/5BBYrB2q4bCqyYFvyJ2kipbGMmhIM9FQZJX2KB0gTZ7wzOaEAmudEsvMm adzK7DhCEDtDFdBIWTkkZOI3pURhJOFgnCT4sopQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzkaller , Kuniyuki Iwashima , Paolo Abeni , Sasha Levin Subject: [PATCH 5.10 337/459] tipc: Fix use-after-free of kernel socket in cleanup_bearer(). Date: Thu, 12 Dec 2024 16:01:15 +0100 Message-ID: <20241212144306.974809038@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241212144253.511169641@linuxfoundation.org> References: <20241212144253.511169641@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kuniyuki Iwashima [ Upstream commit 6a2fa13312e51a621f652d522d7e2df7066330b6 ] syzkaller reported a use-after-free of UDP kernel socket in cleanup_bearer() without repro. [0][1] When bearer_disable() calls tipc_udp_disable(), cleanup of the UDP kernel socket is deferred by work calling cleanup_bearer(). tipc_net_stop() waits for such works to finish by checking tipc_net(net)->wq_count. However, the work decrements the count too early before releasing the kernel socket, unblocking cleanup_net() and resulting in use-after-free. Let's move the decrement after releasing the socket in cleanup_bearer(). [0]: ref_tracker: net notrefcnt@000000009b3d1faf has 1/1 users at sk_alloc+0x438/0x608 inet_create+0x4c8/0xcb0 __sock_create+0x350/0x6b8 sock_create_kern+0x58/0x78 udp_sock_create4+0x68/0x398 udp_sock_create+0x88/0xc8 tipc_udp_enable+0x5e8/0x848 __tipc_nl_bearer_enable+0x84c/0xed8 tipc_nl_bearer_enable+0x38/0x60 genl_family_rcv_msg_doit+0x170/0x248 genl_rcv_msg+0x400/0x5b0 netlink_rcv_skb+0x1dc/0x398 genl_rcv+0x44/0x68 netlink_unicast+0x678/0x8b0 netlink_sendmsg+0x5e4/0x898 ____sys_sendmsg+0x500/0x830 [1]: BUG: KMSAN: use-after-free in udp_hashslot include/net/udp.h:85 [inline] BUG: KMSAN: use-after-free in udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 udp_hashslot include/net/udp.h:85 [inline] udp_lib_unhash+0x3b8/0x930 net/ipv4/udp.c:1979 sk_common_release+0xaf/0x3f0 net/core/sock.c:3820 inet_release+0x1e0/0x260 net/ipv4/af_inet.c:437 inet6_release+0x6f/0xd0 net/ipv6/af_inet6.c:489 __sock_release net/socket.c:658 [inline] sock_release+0xa0/0x210 net/socket.c:686 cleanup_bearer+0x42d/0x4c0 net/tipc/udp_media.c:819 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244 Uninit was created at: slab_free_hook mm/slub.c:2269 [inline] slab_free mm/slub.c:4580 [inline] kmem_cache_free+0x207/0xc40 mm/slub.c:4682 net_free net/core/net_namespace.c:454 [inline] cleanup_net+0x16f2/0x19d0 net/core/net_namespace.c:647 process_one_work kernel/workqueue.c:3229 [inline] process_scheduled_works+0xcaf/0x1c90 kernel/workqueue.c:3310 worker_thread+0xf6c/0x1510 kernel/workqueue.c:3391 kthread+0x531/0x6b0 kernel/kthread.c:389 ret_from_fork+0x60/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:244 CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted 6.12.0-rc1-00131-gf66ebf37d69c #7 91723d6f74857f70725e1583cba3cf4adc716cfa Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 Workqueue: events cleanup_bearer Fixes: 26abe14379f8 ("net: Modify sk_alloc to not reference count the netns of kernel sockets.") Reported-by: syzkaller Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241127050512.28438-1-kuniyu@amazon.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/tipc/udp_media.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/tipc/udp_media.c b/net/tipc/udp_media.c index ec6d7730b8522..d54b5c1d3c83c 100644 --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -810,10 +810,10 @@ static void cleanup_bearer(struct work_struct *work) kfree_rcu(rcast, rcu); } - atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); dst_cache_destroy(&ub->rcast.dst_cache); udp_tunnel_sock_release(ub->ubsock); synchronize_net(); + atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); kfree(ub); } -- 2.43.0