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 A95BC2FE571; Tue, 12 Aug 2025 18:40:43 +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=1755024043; cv=none; b=m7q3Yk3L6yI9pSJfaRiuTa7lTTPJZgeJdzd0U0yizVVbizMqggOjtS4BCWNO8GDBkCtRVjTAdV7Jy94AKElrgUkyLQCzIRUophwWx72gZqjNdn52RWmClRqwK2pM0NB9q030DR3fYjamtV2ajWC8nDQVrHMUIcks5lqwjlaCor4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755024043; c=relaxed/simple; bh=0EUm9J9D94tPi1uwVTKXTwzg6Y42cYUoOAxm59aRdsM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NznYmUpZkDas17Nj1Cerg45iLqxsUvlpCFC0wjzGpNkD1Cd0+mugb9yKtenR+Pz9OFd5fO/s/CdL8dtgo9DkisF6JxuNGETUaj2l5fUcMLDzVZepNTzHOvfuynpWHed7lfQi8Y9KunKmy8tPrXf1NkUaUi4YnZY1qOmWERyUxm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=LZEigW3t; 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="LZEigW3t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17690C4CEF0; Tue, 12 Aug 2025 18:40:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1755024043; bh=0EUm9J9D94tPi1uwVTKXTwzg6Y42cYUoOAxm59aRdsM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LZEigW3t6ts5/E42QQw4UUDvpjuk1JZAYrWqokxpHB1MwDoNoGfYLF2UrOMTbyj1s j/0eIJ5+Im/YW5haYsUOM1EklmrpUqsY1xaxNRq2EHfu85vhiCgAdZmnk5Fjlsxsqh Ih2kzyUPPP+J/62zickuFt771Uulwd9eRG2Q/2Vc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+ac3c79181f6aecc5120c@syzkaller.appspotmail.com, Ivan Pravdin , Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 6.16 257/627] Bluetooth: hci_devcd_dump: fix out-of-bounds via dev_coredumpv Date: Tue, 12 Aug 2025 19:29:12 +0200 Message-ID: <20250812173429.094146491@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250812173419.303046420@linuxfoundation.org> References: <20250812173419.303046420@linuxfoundation.org> User-Agent: quilt/0.68 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 6.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ivan Pravdin [ Upstream commit 7af4d7b53502286c6cf946d397ab183e76d14820 ] Currently both dev_coredumpv and skb_put_data in hci_devcd_dump use hdev->dump.head. However, dev_coredumpv can free the buffer. From dev_coredumpm_timeout documentation, which is used by dev_coredumpv: > Creates a new device coredump for the given device. If a previous one hasn't > been read yet, the new coredump is discarded. The data lifetime is determined > by the device coredump framework and when it is no longer needed the @free > function will be called to free the data. If the data has not been read by the userspace yet, dev_coredumpv will discard new buffer, freeing hdev->dump.head. This leads to vmalloc-out-of-bounds error when skb_put_data tries to access hdev->dump.head. A crash report from syzbot illustrates this: ================================================================== BUG: KASAN: vmalloc-out-of-bounds in skb_put_data include/linux/skbuff.h:2752 [inline] BUG: KASAN: vmalloc-out-of-bounds in hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258 Read of size 140 at addr ffffc90004ed5000 by task kworker/u9:2/5844 CPU: 1 UID: 0 PID: 5844 Comm: kworker/u9:2 Not tainted 6.14.0-syzkaller-10892-g4e82c87058f4 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: hci0 hci_devcd_timeout Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xc3/0x670 mm/kasan/report.c:521 kasan_report+0xe0/0x110 mm/kasan/report.c:634 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189 __asan_memcpy+0x23/0x60 mm/kasan/shadow.c:105 skb_put_data include/linux/skbuff.h:2752 [inline] hci_devcd_dump+0x142/0x240 net/bluetooth/coredump.c:258 hci_devcd_timeout+0xb5/0x2e0 net/bluetooth/coredump.c:413 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3319 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400 kthread+0x3c2/0x780 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 The buggy address ffffc90004ed5000 belongs to a vmalloc virtual mapping Memory state around the buggy address: ffffc90004ed4f00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90004ed4f80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 >ffffc90004ed5000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90004ed5080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90004ed5100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== To avoid this issue, reorder dev_coredumpv to be called after skb_put_data that does not free the data. Reported-by: syzbot+ac3c79181f6aecc5120c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ac3c79181f6aecc5120c Fixes: b257e02ecc46 ("HCI: coredump: Log devcd dumps into the monitor") Tested-by: syzbot+ac3c79181f6aecc5120c@syzkaller.appspotmail.com Signed-off-by: Ivan Pravdin Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/coredump.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/net/bluetooth/coredump.c b/net/bluetooth/coredump.c index 819eacb38762..720cb79adf96 100644 --- a/net/bluetooth/coredump.c +++ b/net/bluetooth/coredump.c @@ -249,15 +249,15 @@ static void hci_devcd_dump(struct hci_dev *hdev) size = hdev->dump.tail - hdev->dump.head; - /* Emit a devcoredump with the available data */ - dev_coredumpv(&hdev->dev, hdev->dump.head, size, GFP_KERNEL); - /* Send a copy to monitor as a diagnostic packet */ skb = bt_skb_alloc(size, GFP_ATOMIC); if (skb) { skb_put_data(skb, hdev->dump.head, size); hci_recv_diag(hdev, skb); } + + /* Emit a devcoredump with the available data */ + dev_coredumpv(&hdev->dev, hdev->dump.head, size, GFP_KERNEL); } static void hci_devcd_handle_pkt_complete(struct hci_dev *hdev, -- 2.39.5