From patchwork Sat Apr 27 17:43:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sungwoo Kim X-Patchwork-Id: 792745 Received: from mail-qk1-f181.google.com (mail-qk1-f181.google.com [209.85.222.181]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF03812B75; Sat, 27 Apr 2024 17:44:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.181 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714239898; cv=none; b=Gnh2UJgFo69b97DtaI11pFUqN+r2VEM8agcZi08saB/VwmpXD0Apo1gd97uiHRtoIQ/WRLX92JEIdkbIQ/eaLuiLWE53ZlMH/6iS+b6sVTGv/d3lwvCHuWRWJHtbd0iHMV3cpslKAIq1tLU0RJg09x0B303oQ6wZN9pBq1qhKSU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714239898; c=relaxed/simple; bh=v+w1XSNzRiJCHarnE3KPWdKOCtHwseSrLnyxVzYQljs=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=ExbiNoQQX+o6a4+qKMFj2fxtVYbkWMf7Pb3/QVSwocgOwuRnLknyt8D4zc16htIC27MThGOs8sRzgmk36HQUZIkuZJxbhD3dptczIysFxYm30L7l7wGHZhb2nTrAcC6cAXlOfxLIq0b+7G9rQpM2cJ4DY+rYTgzrRKjT3NxiICc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=sung-woo.kim; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.client-ip=209.85.222.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=sung-woo.kim Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-qk1-f181.google.com with SMTP id af79cd13be357-78f05035f56so215573785a.3; Sat, 27 Apr 2024 10:44:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714239896; x=1714844696; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=tVwHFjP3dpqwH6JSPl11eVl29KJCyNCQ2GOP51xUw2A=; b=XNqJcFoWSrHmc5fcMyGzGAQQhy2L1cChYHGh1HcWL2mQ5DZ9mKyjUEt8p+shxtBlcN hV1Xtbt7ZTtAluVTqZKOiFw3cMbFLaNjcSVPdKSRaOJGhnxUsaUJ81QTcEbI+k/Gy+3b A2ZQGBKQmJ4MLKbUyfICo06ps9ly9Qp1YIJ+lrBIghOxb2/oqj7DELtDobYiXWEdNTJw pSCIkf+eANUcFyxNQ8T4A0tiB2w/bhkESChue+PsWGVv1Ie1qO4hqngTFfudejAm63ZW xIJUvubtRG7daOcLTKjskEJuL1YrWxihWYMtwZdrzBskt93jL7NJ1w2/wcfI7qgfSf9m 85GA== X-Forwarded-Encrypted: i=1; AJvYcCVQ/8+QOXJRh/m/en8DkNh7Z0klTx6v/PnOyPqL4TlDQh2fQvXIHeSYCVN496Ftwa3oTbtmrAlEgsE3/iUL7zuLQDmMe6yQnzlpqVVZ0D4FXqQpQcknOF/NK8BvXwxzlMQ6YynbyC+ujMKWgs3V X-Gm-Message-State: AOJu0YzdWW0J7J49YAW4Pdmb25cKdJwHaajtdoTAX4YeJzJbDP3Kd6eo XUM64v4hcx1pNjj5Xvj+yLtJICmntdwjHYb9x9pkpCeBH/nIK9p6 X-Google-Smtp-Source: AGHT+IEUjy/2KbG2uXcmZGGrB38i66lA7kXt6CZYsgBCMUmY8OUiZtQcdJd3SZmOdljJhMaYpENAOw== X-Received: by 2002:a37:de08:0:b0:78d:6649:4c79 with SMTP id h8-20020a37de08000000b0078d66494c79mr7640627qkj.70.1714239895507; Sat, 27 Apr 2024 10:44:55 -0700 (PDT) Received: from tofu.cs.purdue.edu ([128.210.0.165]) by smtp.gmail.com with ESMTPSA id wx37-20020a05620a5a6500b0078eebee6a49sm7400250qkn.85.2024.04.27.10.44.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 27 Apr 2024 10:44:54 -0700 (PDT) From: Sungwoo Kim To: Cc: daveti@purdue.edu, dan.carpenter@linaro.org, Sungwoo Kim , Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_connect() Date: Sat, 27 Apr 2024 13:43:34 -0400 Message-Id: <20240427174333.457156-1-iam@sung-woo.kim> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add an hold and lock the channel at l2cap_connect() to avoid use after free. Also make the l2cap_connect() return type void. Nothing is using the returned value but it is ugly to return a potentially freed pointer. Making i void will help with backports because earlier kernels did use the return value. Now the compile will break for kernels where this patch is not a complete fix. Thank you for your help, Dan. Call stack summary: [use] l2cap_bredr_sig_cmd l2cap_connect ┌ mutex_lock(&conn->chan_lock); │ chan = pchan->ops->new_connection(pchan); <- alloc chan │ __l2cap_chan_add(conn, chan); │ l2cap_chan_hold(chan); │ list_add(&chan->list, &conn->chan_l); ... (1) └ mutex_unlock(&conn->chan_lock); chan->conf_state ... (4) <- use after free [free] l2cap_conn_del ┌ mutex_lock(&conn->chan_lock); │ foreach chan in conn->chan_l: ... (2) │ l2cap_chan_put(chan); │ l2cap_chan_destroy │ kfree(chan) ... (3) <- chan freed └ mutex_unlock(&conn->chan_lock); ================================================================== BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] BUG: KASAN: slab-use-after-free in l2cap_connect+0xa67/0x11a0 net/bluetooth/l2cap_core.c:4260 Read of size 8 at addr ffff88810bf040a0 by task kworker/u3:1/311 CPU: 0 PID: 311 Comm: kworker/u3:1 Not tainted 6.8.0+ #61 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Workqueue: hci0 hci_rx_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x85/0xb0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x18f/0x560 mm/kasan/report.c:488 kasan_report+0xd7/0x110 mm/kasan/report.c:601 kasan_check_range+0x262/0x2f0 mm/kasan/generic.c:189 __kasan_check_read+0x15/0x20 mm/kasan/shadow.c:31 instrument_atomic_read include/linux/instrumented.h:68 [inline] _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline] l2cap_connect+0xa67/0x11a0 net/bluetooth/l2cap_core.c:4260 l2cap_bredr_sig_cmd+0x17fe/0x9a70 l2cap_sig_channel net/bluetooth/l2cap_core.c:6539 [inline] l2cap_recv_frame+0x82e/0x86a0 net/bluetooth/l2cap_core.c:7818 l2cap_recv_acldata+0x379/0xbe0 net/bluetooth/l2cap_core.c:8536 hci_acldata_packet net/bluetooth/hci_core.c:3876 [inline] hci_rx_work+0x64b/0xcb0 net/bluetooth/hci_core.c:4111 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x6b9/0xdc0 kernel/workqueue.c:2706 worker_thread+0xb2b/0x13d0 kernel/workqueue.c:2787 kthread+0x2a9/0x340 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 Allocated by task 311: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 kasan_save_alloc_info+0x3c/0x50 mm/kasan/generic.c:575 poison_kmalloc_redzone mm/kasan/common.c:370 [inline] __kasan_kmalloc+0xa2/0xc0 mm/kasan/common.c:387 kasan_kmalloc include/linux/kasan.h:211 [inline] kmalloc_trace+0x1c9/0x390 mm/slub.c:4012 kmalloc include/linux/slab.h:590 [inline] kzalloc include/linux/slab.h:711 [inline] l2cap_chan_create+0x59/0xc80 net/bluetooth/l2cap_core.c:466 l2cap_sock_alloc net/bluetooth/l2cap_sock.c:1849 [inline] l2cap_sock_new_connection_cb+0x14d/0x2a0 net/bluetooth/l2cap_sock.c:1457 l2cap_connect+0x329/0x11a0 net/bluetooth/l2cap_core.c:4176 l2cap_bredr_sig_cmd+0x17fe/0x9a70 l2cap_sig_channel net/bluetooth/l2cap_core.c:6539 [inline] l2cap_recv_frame+0x82e/0x86a0 net/bluetooth/l2cap_core.c:7818 l2cap_recv_acldata+0x379/0xbe0 net/bluetooth/l2cap_core.c:8536 hci_acldata_packet net/bluetooth/hci_core.c:3876 [inline] hci_rx_work+0x64b/0xcb0 net/bluetooth/hci_core.c:4111 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x6b9/0xdc0 kernel/workqueue.c:2706 worker_thread+0xb2b/0x13d0 kernel/workqueue.c:2787 kthread+0x2a9/0x340 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 Freed by task 66: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x30/0x70 mm/kasan/common.c:68 kasan_save_free_info+0x44/0x50 mm/kasan/generic.c:589 poison_slab_object+0x11a/0x190 mm/kasan/common.c:240 __kasan_slab_free+0x3b/0x60 mm/kasan/common.c:256 kasan_slab_free include/linux/kasan.h:184 [inline] slab_free_hook mm/slub.c:2121 [inline] slab_free mm/slub.c:4299 [inline] kfree+0x106/0x2e0 mm/slub.c:4409 l2cap_chan_destroy net/bluetooth/l2cap_core.c:509 [inline] kref_put include/linux/kref.h:65 [inline] l2cap_chan_put+0x1e7/0x2b0 net/bluetooth/l2cap_core.c:533 l2cap_conn_del+0x38e/0x5f0 net/bluetooth/l2cap_core.c:1929 l2cap_connect_cfm+0xc2/0x11e0 net/bluetooth/l2cap_core.c:8254 hci_connect_cfm include/net/bluetooth/hci_core.h:1986 [inline] hci_conn_failed+0x202/0x370 net/bluetooth/hci_conn.c:1289 hci_abort_conn_sync+0x913/0xae0 net/bluetooth/hci_sync.c:5359 abort_conn_sync+0xda/0x110 net/bluetooth/hci_conn.c:2988 hci_cmd_sync_work+0x20d/0x3e0 net/bluetooth/hci_sync.c:306 process_one_work kernel/workqueue.c:2633 [inline] process_scheduled_works+0x6b9/0xdc0 kernel/workqueue.c:2706 worker_thread+0xb2b/0x13d0 kernel/workqueue.c:2787 kthread+0x2a9/0x340 kernel/kthread.c:388 ret_from_fork+0x5c/0x90 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:243 The buggy address belongs to the object at ffff88810bf04000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 160 bytes inside of freed 1024-byte region [ffff88810bf04000, ffff88810bf04400) The buggy address belongs to the physical page: page:00000000567b7faa refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10bf04 head:00000000567b7faa order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x17ffffc0000840(slab|head|node=0|zone=2|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 0017ffffc0000840 ffff888100041dc0 0000000000000000 0000000000000001 raw: 0000000000000000 0000000080080008 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88810bf03f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff88810bf04000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810bf04080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810bf04100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810bf04180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Fixes: 73ffa904b782 ("Bluetooth: Move conf_{req,rsp} stuff to struct l2cap_chan") Signed-off-by: Sungwoo Kim --- V1 -> V2: Make l2cap_connect() return void. Fix a wrong stack trace attached. net/bluetooth/l2cap_core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 84fc70862..e7c18267c 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -3902,7 +3902,7 @@ static inline int l2cap_command_rej(struct l2cap_conn *conn, return 0; } -static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn, +static void l2cap_connect(struct l2cap_conn *conn, struct l2cap_cmd_hdr *cmd, u8 *data, u8 rsp_code, u8 amp_id) { @@ -3953,6 +3953,9 @@ static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn, if (!chan) goto response; + l2cap_chan_hold(chan); + l2cap_chan_lock(chan); + /* For certain devices (ex: HID mouse), support for authentication, * pairing and bonding is optional. For such devices, inorder to avoid * the ACL alive for too long after L2CAP disconnection, reset the ACL @@ -4041,7 +4044,10 @@ static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn, chan->num_conf_req++; } - return chan; + if (chan) { + l2cap_chan_unlock(chan); + l2cap_chan_put(chan); + } } static int l2cap_connect_req(struct l2cap_conn *conn,