From nobody Sun May 19 17:22:33 2024 Received: from mail-qv1-f47.google.com (mail-qv1-f47.google.com [209.85.219.47]) (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 86888210FF; Fri, 26 Apr 2024 07:20:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.47 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714116028; cv=none; b=SHXRomEqgcc8rzMdngwTqMYQ5Pehfc/uLkDHLhC+lg22c7ijcdKfv85SGLaMx6friQMznFCYihQ+InfiJioKQBvCD+cLdf+DgM9/vu8jW324STJkmgBCrgD6RjaWRzfnTlOXOUU8qK2I8WgnkurN3dG/der2kBe+i9Qqcgm5vCM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714116028; c=relaxed/simple; bh=ZLkgAm7OrwCtlXsltCwfJqKUmyX5N3G73Ksssl3/2mE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=md/shAHlqC+76ifLQnneRMV6PfNlfaqQXteh3eIPK/u1mVHoXDIH4PSyXURWbq+fg8Vl3as9bwFhsn/f0Fl/hD6WaQovwRbFche5K3uCLIPCz3jrQCbH13Qd3qqTgH4Tz8K853QKIHD9kfny1+zxzJ7GkwSXC6hHUTe66Agq6w8= 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=209.85.219.47 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-qv1-f47.google.com with SMTP id 6a1803df08f44-6a071595d22so9871096d6.3; Fri, 26 Apr 2024 00:20:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1714116025; x=1714720825; 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=xRvU0xUlHTJYvKA7qTgsZecNFP1QfgtH2vvFVAr0EAk=; b=Eh5VPMapYPfQ2mXbVy+lCJxqolzBLFXy6fUSgvJjJCIbMmxf5Znco7Rx2ocmQN+JT6 5ii3oaC66w7uODUq3hJkI9ZWFz16oLxit2Rx0CGvopDLS4cOvqWn573RcGfg2/ZCyX1J HYwOiIQ65v4UWgdt+MiIx26YpoTlRmFLj2jL2QqclWz1kIi/IFI4mwNV4y1yhZPz/Twd QbpIfgosZbTRB+8uMhgn1GK8x+iPrc4hGD/2oR5wdmzQjMVTaA3R7hDNq0xiBi+bNwQN zUNAycQqrgD6oCyWXu4dPYc2nwBaTy5xrh0dbfjmWju39xqb2T2HQXGsF4WBBa3I+M/p /g6g== X-Forwarded-Encrypted: i=1; AJvYcCXkBpp4s6pzu4ZXhMQdHHOifZGOXPFsb+2qSpS/s94sN+3QvriPUzDMflxx7DaG1PNi70oc6a63mNrcz4UMG3xvkPCAyp4MJ2P1U5VZZf3zjXcOD6oOUwjdgHXEfZpwODBeC+c+4gzoHc5Ehu9P X-Gm-Message-State: AOJu0YwD730GCudX9Cjzh8u4Zzn0WK4qZGgiUilVRSh1dcTWJntb6E5V LZ59Nz5XyNNgFN0bE0or0omQ1SUIJTi0BTMUKh7fNgusAeWOQzAr X-Google-Smtp-Source: AGHT+IEynjR4BjT04NoxHWMoNQmwIYnX9UW30F3lzWXty1YYzgV3BFuW8OiGdCB85rdrtlc7nBZB4w== X-Received: by 2002:a05:6214:48b:b0:6a0:57f1:c536 with SMTP id pt11-20020a056214048b00b006a057f1c536mr2404970qvb.10.1714116024935; Fri, 26 Apr 2024 00:20:24 -0700 (PDT) Received: from tofu.cs.purdue.edu ([128.210.0.165]) by smtp.gmail.com with ESMTPSA id l2-20020a056214028200b006a0afa5bce3sm222036qvv.55.2024.04.26.00.20.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Apr 2024 00:20:24 -0700 (PDT) From: Sungwoo Kim To: Cc: daveti@purdue.edu, Sungwoo Kim , Marcel Holtmann , Johan Hedberg , Luiz Augusto von Dentz , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_send_cmd Date: Fri, 26 Apr 2024 03:20:05 -0400 Message-Id: <20240426072006.358802-1-iam@sung-woo.kim> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hello, could you review a bug and its fix? This is a racy bug. Call stack is as below: [free] l2cap_conn_del =E2=94=8C mutex_lock(&conn->chan_lock); =E2=94=82 foreach chan in conn->chan_l: ... (2) =E2=94=82 l2cap_chan_put(chan); =E2=94=82 l2cap_chan_destroy =E2=94=82 kfree(chan) ... (3) =E2=94=94 mutex_unlock(&conn->chan_lock); [use] l2cap_bredr_sig_cmd l2cap_connect =E2=94=8C mutex_lock(&conn->chan_lock); =E2=94=82 chan =3D pchan->ops->new_connection(pchan); // alloc chan =E2=94=82 __l2cap_chan_add(conn, chan); =E2=94=82 l2cap_chan_hold(chan); =E2=94=82 list_add(&chan->list, &conn->chan_l); ... (1) =E2=94=94 mutex_unlock(&conn->chan_lock); chan->conf_state // uaf at chan ... (4) To fix this, this patch holds and locks the l2cap channel. Thanks, Sungwoo. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D BUG: KASAN: slab-use-after-free in l2cap_send_cmd+0x5dc/0x830 net/bluetooth= /l2cap_core.c:968 Read of size 1 at addr ffff88810b62c274 by task kworker/0:1/10 CPU: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.8.0+ #61 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/= 2014 Workqueue: events l2cap_info_timeout 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 __asan_report_load1_noabort+0x18/0x20 mm/kasan/report_generic.c:378 l2cap_send_cmd+0x5dc/0x830 net/bluetooth/l2cap_core.c:968 l2cap_send_conn_req net/bluetooth/l2cap_core.c:1286 [inline] l2cap_start_connection+0x25e/0x530 net/bluetooth/l2cap_core.c:1514 l2cap_conn_start+0x952/0xe60 net/bluetooth/l2cap_core.c:1661 l2cap_info_timeout+0x5f/0x90 net/bluetooth/l2cap_core.c:1807 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 290: 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] __do_kmalloc_node mm/slub.c:3981 [inline] __kmalloc+0x228/0x4d0 mm/slub.c:3994 kmalloc include/linux/slab.h:594 [inline] kzalloc include/linux/slab.h:711 [inline] hci_alloc_dev_priv+0x30/0x1ea0 net/bluetooth/hci_core.c:2468 hci_alloc_dev include/net/bluetooth/hci_core.h:1651 [inline] __vhci_create_device drivers/bluetooth/hci_vhci.c:406 [inline] vhci_create_device+0x10e/0x710 drivers/bluetooth/hci_vhci.c:480 vhci_get_user drivers/bluetooth/hci_vhci.c:537 [inline] vhci_write+0x398/0x460 drivers/bluetooth/hci_vhci.c:617 call_write_iter include/linux/fs.h:2087 [inline] new_sync_write fs/read_write.c:497 [inline] vfs_write+0x9ee/0xd40 fs/read_write.c:590 ksys_write+0x103/0x1f0 fs/read_write.c:643 __do_sys_write fs/read_write.c:655 [inline] __se_sys_write fs/read_write.c:652 [inline] __x64_sys_write+0x84/0xa0 fs/read_write.c:652 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x84/0x120 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Freed by task 1158: 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 hci_release_dev+0x1114/0x1250 net/bluetooth/hci_core.c:2799 bt_host_release+0x77/0x90 net/bluetooth/hci_sysfs.c:94 device_release+0xa4/0x1d0 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x1f1/0x410 lib/kobject.c:737 put_device+0x28/0x40 drivers/base/core.c:3747 hci_free_dev+0x25/0x30 net/bluetooth/hci_core.c:2594 vhci_release+0x91/0xe0 drivers/bluetooth/hci_vhci.c:675 __fput+0x35b/0x740 fs/file_table.c:376 ____fput+0x1e/0x30 fs/file_table.c:404 task_work_run+0x1d9/0x270 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0x823/0x23e0 kernel/exit.c:871 do_group_exit+0x1f1/0x2b0 kernel/exit.c:1020 get_signal+0x1387/0x14d0 kernel/signal.c:2893 arch_do_signal_or_restart+0x3b/0x650 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline] syscall_exit_to_user_mode+0x71/0x180 kernel/entry/common.c:212 do_syscall_64+0x90/0x120 arch/x86/entry/common.c:89 entry_SYSCALL_64_after_hwframe+0x6e/0x76 Last potentially related work creation: kasan_save_stack+0x2f/0x50 mm/kasan/common.c:47 __kasan_record_aux_stack+0xc6/0xe0 mm/kasan/generic.c:551 kasan_record_aux_stack_noalloc+0xf/0x20 mm/kasan/generic.c:561 insert_work+0x3a/0x1d0 kernel/workqueue.c:1653 __queue_work+0xa5b/0xdc0 kernel/workqueue.c:1806 queue_work_on+0x74/0xa0 kernel/workqueue.c:1837 queue_work include/linux/workqueue.h:548 [inline] hci_recv_frame+0x375/0x490 net/bluetooth/hci_core.c:2947 hci_reset_dev+0x126/0x170 net/bluetooth/hci_core.c:2904 hci_ncmd_timeout+0xb1/0xd0 net/bluetooth/hci_core.c:1525 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 Second to last potentially related work creation: kasan_save_stack+0x2f/0x50 mm/kasan/common.c:47 __kasan_record_aux_stack+0xc6/0xe0 mm/kasan/generic.c:551 kasan_record_aux_stack_noalloc+0xf/0x20 mm/kasan/generic.c:561 insert_work kernel/workqueue.c:1653 [inline] __queue_work+0x8cf/0xdc0 kernel/workqueue.c:1802 delayed_work_timer_fn+0x6a/0x90 kernel/workqueue.c:1931 call_timer_fn+0x44/0x240 kernel/time/timer.c:1700 expire_timers kernel/time/timer.c:1746 [inline] __run_timers+0x63a/0x870 kernel/time/timer.c:2038 run_timer_softirq+0x26/0x40 kernel/time/timer.c:2051 __do_softirq+0x180/0x523 kernel/softirq.c:553 The buggy address belongs to the object at ffff88810b62c000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 628 bytes inside of freed 8192-byte region [ffff88810b62c000, ffff88810b62e000) The buggy address belongs to the physical page: page:000000007f8eb4fe refcount:1 mapcount:0 mapping:0000000000000000 index:= 0x0 pfn:0x10b628 head:000000007f8eb4fe order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 anon flags: 0x17ffffc0000840(slab|head|node=3D0|zone=3D2|lastcpupid=3D0x1ff= fff) page_type: 0xffffffff() raw: 0017ffffc0000840 ffff888100042280 0000000000000000 0000000000000001 raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88810b62c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810b62c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88810b62c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88810b62c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88810b62c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D Signed-off-by: Sungwoo Kim --- net/bluetooth/l2cap_core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 84fc70862..a8f414ab8 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -3953,6 +3953,9 @@ static struct l2cap_chan *l2cap_connect(struct l2cap_= conn *conn, if (!chan) goto response; =20 + 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 @@ -4041,6 +4044,11 @@ static struct l2cap_chan *l2cap_connect(struct l2cap= _conn *conn, chan->num_conf_req++; } =20 + if (chan) { + l2cap_chan_unlock(chan); + l2cap_chan_put(chan); + } + return chan; } =20 --=20 2.34.1