From nobody Sun Feb 8 20:28:48 2026 Received: from smtp-relay-internal-1.canonical.com (smtp-relay-internal-1.canonical.com [185.125.188.123]) (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 2A1BE134A8 for ; Mon, 2 Dec 2024 02:30:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.125.188.123 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733106660; cv=none; b=CY2Gg4UpF/yHhyL4o64m0jlBJp+AbFb1tOEJzwVl6vNqQXur2+yBMH8Yj0Xc/W/hNiw5hGSXVFME+qe2IxyM0UzqWTgNy8wWAptjR8ctBZ4ZczsO6un0k+gTYMGCM8t5UkZbUMN2bXjOZc1lrCEgpjr+1bA+1NxggBMIKK9dgIM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733106660; c=relaxed/simple; bh=Zdq1ZwogLgVqgL+z9O7uP9pI89UJVYGAX8lIGuQkfMg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=B2aNvwMzP6+E5J3Z2kKIRjOgdJzyfY9X+yjr/qADgu1uZXOS2PNniO1yqnqSnU2prwdubJmejgKqJ3KTK2eyA0KsPDOXf366iU1kOfumn1ks52NJL3PdHiTCuqn253dIgZ50pltD7J0/VrykWL5RxOhI8fhmYyzTq4jDTEuygdA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canonical.com; spf=pass smtp.mailfrom=canonical.com; dkim=pass (2048-bit key) header.d=canonical.com header.i=@canonical.com header.b=TgFfQ18p; arc=none smtp.client-ip=185.125.188.123 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=canonical.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=canonical.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=canonical.com header.i=@canonical.com header.b="TgFfQ18p" Received: from mail-pf1-f200.google.com (mail-pf1-f200.google.com [209.85.210.200]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-1.canonical.com (Postfix) with ESMTPS id ACC233F288 for ; Mon, 2 Dec 2024 02:30:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1733106648; bh=+jndlWKS4Xdsna9rr9EhkPhfFpnli2KtOvGE3QLRJWI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=TgFfQ18pjSkaU67AOUn8XHIgvIgQ7fzxh2DmS/qZXOV1jhNVAVaeUTD0yPJ+/RkPL J7ZlZBy4G3xAZL/NiM9NYPmQDIekWypfIMV6uRzk7JUtrRJlRYp5cq7Ao3MuFovfUp Su5zIFNV5J9SUPkEagEkBrYmv6YGW9iF5vFZjxKb8MdToC0YZXiCDMTMjuQRP1DQ/4 PMdBufM0gQfbs/mcpqXVdVihaU13ZmiEBcxujW5R+2ri4qxOOtGPtJmuumWIPTqbrb CqX6bwpvDl7Tx0ltzyjkZ5L8PMgATHUUTQvzmq7G2spPFLZIvKq+yQ+xvIL1J+1B2g RJO6ySIwTtFBA== Received: by mail-pf1-f200.google.com with SMTP id d2e1a72fcca58-7251d77ddb7so5058869b3a.0 for ; Sun, 01 Dec 2024 18:30:48 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733106647; x=1733711447; 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=+jndlWKS4Xdsna9rr9EhkPhfFpnli2KtOvGE3QLRJWI=; b=FFLYJcysOJklyxA45Mf7soug5Y4ccdU343ulntai727PawIlGC3H2B5em/WMywDer3 oTEZt0Sw22guBIhBLtgrCYV56o+ymT+BCEthVjQQOK4NUfgTcfepn2SjQZoNe3+PtfuW f4C3D3MtA6WRYYFd5xfzXEBagjO9jwZRfmx6sOmbZm/30SC369eN/ADu5rJGUo3HAHth WunSGDt9nR7FPaABwrUCFL7zVw8i2rZnt+GOdAhb4uAxs+evpew5uOkPK+i/8ZIHAelI B0O9ZmBDeAI2hbODzWB0RthV/uUerkynmnQt3y674UPVLfklltEMCWoFYxwGrvL5UIFY a07g== X-Forwarded-Encrypted: i=1; AJvYcCVuWlka7fSrJflq+C2TYDL8UGn8KCne3XXhUXxjJOwSNkb0KPymmZOjXYwnRsIlqiaAfi4wijPu0vSvR0Y=@vger.kernel.org X-Gm-Message-State: AOJu0Yws9+nnkzJ0O/briNaPOlVOxkxJQeM8voR0k6zaub61DIRQcCOC mQgL7/jr3AOcnOT8yKErW+1B0Uw8iNJmk1IYN9jLv7p+8AV9JhL5PZlJYMlhgAJCniqBEFYUkof u4cZJ4B6vaGIZ7z5LSgvPIlO2KufPE5tLzgRWSu0Qc5h7bHU9KmskOkk7ZR/Cx24CpLExcus98b snqw== X-Gm-Gg: ASbGncuPEq+zVOdmH//a0qGu7oBivpXDnqLRqe+t475efOsqQzn6VEtgjrxqMWNix/p PTCkNP9l3WYrEPBspy8w3qjHb3HxYUQmquLAlycBXAGZWtQVLh4bhsevPr1Ct7GSFjGE7403Msy SA7u58qJ66nCufwzwmX70qT3BCWQY6p/xPUjGf3HruOW+qwfQD6U/eHieTX/NtgcI114iEoTj56 Ozy6rt8cdjCCFwcl1qvfEfEdBGGwdQdZA23OGRfx2DQDQyO+shvS7TmR+Sk/bXUVqds0D9IvH3B ICQJccV+r+/5zu4SPx00LcAUpeycRwUyp69Vi7Z7l7U6SVWglrNS X-Received: by 2002:a17:90b:3901:b0:2ee:cddd:2454 with SMTP id 98e67ed59e1d1-2eecddd2aa9mr3115186a91.15.1733106647176; Sun, 01 Dec 2024 18:30:47 -0800 (PST) X-Google-Smtp-Source: AGHT+IGxhGl95AGvKcN10Yj/5OchnG6inZsxo8Gn1gyPKjD3kWjbNF/yMuICL635d2N3oZktOyD4Cg== X-Received: by 2002:a17:90b:3901:b0:2ee:cddd:2454 with SMTP id 98e67ed59e1d1-2eecddd2aa9mr3115157a91.15.1733106646862; Sun, 01 Dec 2024 18:30:46 -0800 (PST) Received: from rickywu0421-ThinkPad-X1-Carbon-Gen-11.. (211-75-139-220.hinet-ip.hinet.net. [211.75.139.220]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2ee05324801sm6081821a91.1.2024.12.01.18.30.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Dec 2024 18:30:46 -0800 (PST) From: En-Wei Wu To: marcel@holtmann.org, luiz.dentz@gmail.com, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, pmenzel@molgen.mpg.de Cc: quic_tjiang@quicinc.com, kuan-ying.lee@canonical.com, anthony.wong@canonical.com Subject: [PATCH v2] Bluetooth: btusb: avoid NULL pointer dereference in skb_dequeue() Date: Mon, 2 Dec 2024 10:30:41 +0800 Message-ID: <20241202023041.492547-1-en-wei.wu@canonical.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The WCN7851 (0489:e0f3) Bluetooth controller supports firmware crash dump collection through devcoredump. During this process, the crash dump data is queued to a dump queue as skb for further processing. A NULL pointer dereference occurs in skb_dequeue() when processing the dump queue due to improper return value handling: [ 93.672166] Bluetooth: hci0: ACL memdump size(589824) [ 93.672475] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 93.672517] Workqueue: hci0 hci_devcd_rx [bluetooth] [ 93.672598] RIP: 0010:skb_dequeue+0x50/0x80 The issue stems from handle_dump_pkt_qca() returning the wrong value on success. It currently returns the value from hci_devcd_init() (0 on=20 success), but callers expect > 0 to indicate successful dump handling.=20 This causes hci_recv_frame() to free the skb while it's still queued for=20 dump processing, leading to the NULL pointer dereference when=20 hci_devcd_rx() tries to dequeue it. Fix this by: 1. Extracting dump packet detection into new is_dump_pkt_qca() function 2. Making handle_dump_pkt_qca() return 0 on success and negative errno on failure, consistent with other kernel interfaces This prevents premature skb freeing by ensuring proper handling of dump packets. Fixes: 20981ce2d5a5 ("Bluetooth: btusb: Add WCN6855 devcoredump support") Signed-off-by: En-Wei Wu --- changes in v2:=20 - Fix typo in the title - Re-flow a line in the commit message to fit 72 characters - Add a blank line before btusb_recv_acl_qca() drivers/bluetooth/btusb.c | 76 ++++++++++++++++++++++++--------------- 1 file changed, 48 insertions(+), 28 deletions(-) diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index 279fe6c115fa..741be218610e 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -2930,22 +2930,16 @@ static void btusb_coredump_qca(struct hci_dev *hdev) bt_dev_err(hdev, "%s: triggle crash failed (%d)", __func__, err); } =20 -/* - * =3D=3D0: not a dump pkt. - * < 0: fails to handle a dump pkt - * > 0: otherwise. - */ +/* Return: 0 on success, negative errno on failure. */ static int handle_dump_pkt_qca(struct hci_dev *hdev, struct sk_buff *skb) { - int ret =3D 1; + int ret =3D 0; u8 pkt_type; u8 *sk_ptr; unsigned int sk_len; u16 seqno; u32 dump_size; =20 - struct hci_event_hdr *event_hdr; - struct hci_acl_hdr *acl_hdr; struct qca_dump_hdr *dump_hdr; struct btusb_data *btdata =3D hci_get_drvdata(hdev); struct usb_device *udev =3D btdata->udev; @@ -2955,30 +2949,14 @@ static int handle_dump_pkt_qca(struct hci_dev *hdev= , struct sk_buff *skb) sk_len =3D skb->len; =20 if (pkt_type =3D=3D HCI_ACLDATA_PKT) { - acl_hdr =3D hci_acl_hdr(skb); - if (le16_to_cpu(acl_hdr->handle) !=3D QCA_MEMDUMP_ACL_HANDLE) - return 0; sk_ptr +=3D HCI_ACL_HDR_SIZE; sk_len -=3D HCI_ACL_HDR_SIZE; - event_hdr =3D (struct hci_event_hdr *)sk_ptr; - } else { - event_hdr =3D hci_event_hdr(skb); } =20 - if ((event_hdr->evt !=3D HCI_VENDOR_PKT) - || (event_hdr->plen !=3D (sk_len - HCI_EVENT_HDR_SIZE))) - return 0; - sk_ptr +=3D HCI_EVENT_HDR_SIZE; sk_len -=3D HCI_EVENT_HDR_SIZE; =20 dump_hdr =3D (struct qca_dump_hdr *)sk_ptr; - if ((sk_len < offsetof(struct qca_dump_hdr, data)) - || (dump_hdr->vse_class !=3D QCA_MEMDUMP_VSE_CLASS) - || (dump_hdr->msg_type !=3D QCA_MEMDUMP_MSG_TYPE)) - return 0; - - /*it is dump pkt now*/ seqno =3D le16_to_cpu(dump_hdr->seqno); if (seqno =3D=3D 0) { set_bit(BTUSB_HW_SSR_ACTIVE, &btdata->flags); @@ -3052,17 +3030,59 @@ static int handle_dump_pkt_qca(struct hci_dev *hdev= , struct sk_buff *skb) return ret; } =20 +/* Return: true if packet is a dump packet, false otherwise. */ +static bool is_dump_pkt_qca(struct hci_dev *hdev, struct sk_buff *skb) +{ + u8 pkt_type; + u8 *sk_ptr; + unsigned int sk_len; + + struct hci_event_hdr *event_hdr; + struct hci_acl_hdr *acl_hdr; + struct qca_dump_hdr *dump_hdr; + + pkt_type =3D hci_skb_pkt_type(skb); + sk_ptr =3D skb->data; + sk_len =3D skb->len; + + if (pkt_type =3D=3D HCI_ACLDATA_PKT) { + acl_hdr =3D hci_acl_hdr(skb); + if (le16_to_cpu(acl_hdr->handle) !=3D QCA_MEMDUMP_ACL_HANDLE) + return false; + sk_ptr +=3D HCI_ACL_HDR_SIZE; + sk_len -=3D HCI_ACL_HDR_SIZE; + event_hdr =3D (struct hci_event_hdr *)sk_ptr; + } else { + event_hdr =3D hci_event_hdr(skb); + } + + if ((event_hdr->evt !=3D HCI_VENDOR_PKT) + || (event_hdr->plen !=3D (sk_len - HCI_EVENT_HDR_SIZE))) + return false; + + sk_ptr +=3D HCI_EVENT_HDR_SIZE; + sk_len -=3D HCI_EVENT_HDR_SIZE; + + dump_hdr =3D (struct qca_dump_hdr *)sk_ptr; + if ((sk_len < offsetof(struct qca_dump_hdr, data)) + || (dump_hdr->vse_class !=3D QCA_MEMDUMP_VSE_CLASS) + || (dump_hdr->msg_type !=3D QCA_MEMDUMP_MSG_TYPE)) + return false; + + return true; +} + static int btusb_recv_acl_qca(struct hci_dev *hdev, struct sk_buff *skb) { - if (handle_dump_pkt_qca(hdev, skb)) - return 0; + if (is_dump_pkt_qca(hdev, skb)) + return handle_dump_pkt_qca(hdev, skb); return hci_recv_frame(hdev, skb); } =20 static int btusb_recv_evt_qca(struct hci_dev *hdev, struct sk_buff *skb) { - if (handle_dump_pkt_qca(hdev, skb)) - return 0; + if (is_dump_pkt_qca(hdev, skb)) + return handle_dump_pkt_qca(hdev, skb); return hci_recv_frame(hdev, skb); } =20 --=20 2.43.0