From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E3587C00144 for ; Mon, 1 Aug 2022 11:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231408AbiHALsC (ORCPT ); Mon, 1 Aug 2022 07:48:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33988 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230341AbiHALr7 (ORCPT ); Mon, 1 Aug 2022 07:47:59 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B23E357E6; Mon, 1 Aug 2022 04:47:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B37BCB81163; Mon, 1 Aug 2022 11:47:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A712C433D7; Mon, 1 Aug 2022 11:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1659354475; bh=/84djZfIdkDkqzPDIuV+7LN9m1x7972+uqaLrrjqWPY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BZvFxKY76jZHI8Vkyn20ISFHgEt4HoEVYegFZRHmoTpw8qO6RV8SFGspfO+NWeAJP 7D1tBxOE/+k5Dt+rS4MTh6lDKJdFJrPiiuCfUw7UxQ//5+ozsyfdVQ7rsuhE3lk/jH bqzw5HrYhlfANkDyRnxGjRBQbMPbJSQZQHFauxRw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, stable@kernel.org, Lee Jones , Luiz Augusto von Dentz Subject: [PATCH 5.4 01/34] Bluetooth: L2CAP: Fix use-after-free caused by l2cap_chan_put Date: Mon, 1 Aug 2022 13:46:41 +0200 Message-Id: <20220801114128.092552506@linuxfoundation.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20220801114128.025615151@linuxfoundation.org> References: <20220801114128.025615151@linuxfoundation.org> User-Agent: quilt/0.66 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Luiz Augusto von Dentz commit d0be8347c623e0ac4202a1d4e0373882821f56b0 upstream. This fixes the following trace which is caused by hci_rx_work starting up *after* the final channel reference has been put() during sock_close() but *before* the references to the channel have been destroyed, so instead the code now rely on kref_get_unless_zero/l2cap_chan_hold_unless_zero to prevent referencing a channel that is about to be destroyed. refcount_t: increment on 0; use-after-free. BUG: KASAN: use-after-free in refcount_dec_and_test+0x20/0xd0 Read of size 4 at addr ffffffc114f5bf18 by task kworker/u17:14/705 CPU: 4 PID: 705 Comm: kworker/u17:14 Tainted: G S W 4.14.234-00003-g1fb6d0bd49a4-dirty #28 Hardware name: Qualcomm Technologies, Inc. SM8150 V2 PM8150 Google Inc. MSM sm8150 Flame DVT (DT) Workqueue: hci0 hci_rx_work Call trace: dump_backtrace+0x0/0x378 show_stack+0x20/0x2c dump_stack+0x124/0x148 print_address_description+0x80/0x2e8 __kasan_report+0x168/0x188 kasan_report+0x10/0x18 __asan_load4+0x84/0x8c refcount_dec_and_test+0x20/0xd0 l2cap_chan_put+0x48/0x12c l2cap_recv_frame+0x4770/0x6550 l2cap_recv_acldata+0x44c/0x7a4 hci_acldata_packet+0x100/0x188 hci_rx_work+0x178/0x23c process_one_work+0x35c/0x95c worker_thread+0x4cc/0x960 kthread+0x1a8/0x1c4 ret_from_fork+0x10/0x18 Cc: stable@kernel.org Reported-by: Lee Jones Signed-off-by: Luiz Augusto von Dentz Tested-by: Lee Jones Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Greg Kroah-Hartman --- include/net/bluetooth/l2cap.h | 1 net/bluetooth/l2cap_core.c | 61 +++++++++++++++++++++++++++++++++--------- 2 files changed, 49 insertions(+), 13 deletions(-) --- a/include/net/bluetooth/l2cap.h +++ b/include/net/bluetooth/l2cap.h @@ -802,6 +802,7 @@ enum { }; void l2cap_chan_hold(struct l2cap_chan *c); +struct l2cap_chan *l2cap_chan_hold_unless_zero(struct l2cap_chan *c); void l2cap_chan_put(struct l2cap_chan *c); static inline void l2cap_chan_lock(struct l2cap_chan *chan) --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -110,7 +110,8 @@ static struct l2cap_chan *__l2cap_get_ch } /* Find channel with given SCID. - * Returns locked channel. */ + * Returns a reference locked channel. + */ static struct l2cap_chan *l2cap_get_chan_by_scid(struct l2cap_conn *conn, u16 cid) { @@ -118,15 +119,19 @@ static struct l2cap_chan *l2cap_get_chan mutex_lock(&conn->chan_lock); c = __l2cap_get_chan_by_scid(conn, cid); - if (c) - l2cap_chan_lock(c); + if (c) { + /* Only lock if chan reference is not 0 */ + c = l2cap_chan_hold_unless_zero(c); + if (c) + l2cap_chan_lock(c); + } mutex_unlock(&conn->chan_lock); return c; } /* Find channel with given DCID. - * Returns locked channel. + * Returns a reference locked channel. */ static struct l2cap_chan *l2cap_get_chan_by_dcid(struct l2cap_conn *conn, u16 cid) @@ -135,8 +140,12 @@ static struct l2cap_chan *l2cap_get_chan mutex_lock(&conn->chan_lock); c = __l2cap_get_chan_by_dcid(conn, cid); - if (c) - l2cap_chan_lock(c); + if (c) { + /* Only lock if chan reference is not 0 */ + c = l2cap_chan_hold_unless_zero(c); + if (c) + l2cap_chan_lock(c); + } mutex_unlock(&conn->chan_lock); return c; @@ -161,8 +170,12 @@ static struct l2cap_chan *l2cap_get_chan mutex_lock(&conn->chan_lock); c = __l2cap_get_chan_by_ident(conn, ident); - if (c) - l2cap_chan_lock(c); + if (c) { + /* Only lock if chan reference is not 0 */ + c = l2cap_chan_hold_unless_zero(c); + if (c) + l2cap_chan_lock(c); + } mutex_unlock(&conn->chan_lock); return c; @@ -496,6 +509,16 @@ void l2cap_chan_hold(struct l2cap_chan * kref_get(&c->kref); } +struct l2cap_chan *l2cap_chan_hold_unless_zero(struct l2cap_chan *c) +{ + BT_DBG("chan %p orig refcnt %u", c, kref_read(&c->kref)); + + if (!kref_get_unless_zero(&c->kref)) + return NULL; + + return c; +} + void l2cap_chan_put(struct l2cap_chan *c) { BT_DBG("chan %p orig refcnt %d", c, kref_read(&c->kref)); @@ -1812,7 +1835,10 @@ static struct l2cap_chan *l2cap_global_c src_match = !bacmp(&c->src, src); dst_match = !bacmp(&c->dst, dst); if (src_match && dst_match) { - l2cap_chan_hold(c); + c = l2cap_chan_hold_unless_zero(c); + if (!c) + continue; + read_unlock(&chan_list_lock); return c; } @@ -1827,7 +1853,7 @@ static struct l2cap_chan *l2cap_global_c } if (c1) - l2cap_chan_hold(c1); + c1 = l2cap_chan_hold_unless_zero(c1); read_unlock(&chan_list_lock); @@ -4221,6 +4247,7 @@ static inline int l2cap_config_req(struc unlock: l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return err; } @@ -4334,6 +4361,7 @@ static inline int l2cap_config_rsp(struc done: l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return err; } @@ -5062,6 +5090,7 @@ send_move_response: l2cap_send_move_chan_rsp(chan, result); l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return 0; } @@ -5154,6 +5183,7 @@ static void l2cap_move_continue(struct l } l2cap_chan_unlock(chan); + l2cap_chan_put(chan); } static void l2cap_move_fail(struct l2cap_conn *conn, u8 ident, u16 icid, @@ -5183,6 +5213,7 @@ static void l2cap_move_fail(struct l2cap l2cap_send_move_chan_cfm(chan, L2CAP_MC_UNCONFIRMED); l2cap_chan_unlock(chan); + l2cap_chan_put(chan); } static int l2cap_move_channel_rsp(struct l2cap_conn *conn, @@ -5246,6 +5277,7 @@ static int l2cap_move_channel_confirm(st l2cap_send_move_chan_cfm_rsp(conn, cmd->ident, icid); l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return 0; } @@ -5281,6 +5313,7 @@ static inline int l2cap_move_channel_con } l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return 0; } @@ -5653,12 +5686,11 @@ static inline int l2cap_le_credits(struc if (credits > max_credits) { BT_ERR("LE credits overflow"); l2cap_send_disconn_req(chan, ECONNRESET); - l2cap_chan_unlock(chan); /* Return 0 so that we don't trigger an unnecessary * command reject packet. */ - return 0; + goto unlock; } chan->tx_credits += credits; @@ -5669,7 +5701,9 @@ static inline int l2cap_le_credits(struc if (chan->tx_credits) chan->ops->resume(chan); +unlock: l2cap_chan_unlock(chan); + l2cap_chan_put(chan); return 0; } @@ -6983,6 +7017,7 @@ drop: done: l2cap_chan_unlock(chan); + l2cap_chan_put(chan); } static void l2cap_conless_channel(struct l2cap_conn *conn, __le16 psm, @@ -7386,7 +7421,7 @@ static struct l2cap_chan *l2cap_global_f if (src_type != c->src_type) continue; - l2cap_chan_hold(c); + c = l2cap_chan_hold_unless_zero(c); read_unlock(&chan_list_lock); return c; }