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([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-488fc14a61asm332563105e9.15.2026.04.21.03.48.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Apr 2026 03:48:23 -0700 (PDT) From: Tristan Madani To: Luiz Augusto von Dentz Cc: Marcel Holtmann , Sean Wang , Mark Chen , linux-mediatek@lists.infradead.org, stable@vger.kernel.org, linux-bluetooth@vger.kernel.org, Tristan Madani Subject: [PATCH v4] Bluetooth: btmtk: validate WMT event SKB length before struct access Date: Tue, 21 Apr 2026 10:48:22 +0000 Message-ID: <20260421104822.2498025-1-tristmd@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tristan Madani btmtk_usb_hci_wmt_sync() casts the WMT event response SKB data to struct btmtk_hci_wmt_evt (7 bytes) and struct btmtk_hci_wmt_evt_funcc (9 bytes) without first checking that the SKB contains enough data. A short firmware response causes out-of-bounds reads from SKB tailroom. Use skb_pull_data() to validate and advance past the base WMT event header. For the FUNC_CTRL case, pull the additional status field bytes before accessing them. Fixes: d019930b0049 ("Bluetooth: btmtk: move btusb_mtk_hci_wmt_sync to btmtk.c") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- Changes in v4: - Use skb_pull_data() instead of manual length checks, per Luiz Augusto von Dentz. Changes in v3: - CI all pass (CheckPatch, BuildKernel, CheckSparse, etc.). drivers/bluetooth/btmtk.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c index 6fb6ca274..b1a96ebae 100644 --- a/drivers/bluetooth/btmtk.c +++ b/drivers/bluetooth/btmtk.c @@ -695,8 +695,13 @@ static int btmtk_usb_hci_wmt_sync(struct hci_dev *hdev, if (data->evt_skb == NULL) goto err_free_wc; - /* Parse and handle the return WMT event */ - wmt_evt = (struct btmtk_hci_wmt_evt *)data->evt_skb->data; + wmt_evt = skb_pull_data(data->evt_skb, sizeof(*wmt_evt)); + if (!wmt_evt) { + bt_dev_err(hdev, "WMT event too short (%u bytes)", + data->evt_skb->len); + err = -EINVAL; + goto err_free_skb; + } + if (wmt_evt->whdr.op != hdr->op) { bt_dev_err(hdev, "Wrong op received %d expected %d", wmt_evt->whdr.op, hdr->op); @@ -712,7 +717,13 @@ static int btmtk_usb_hci_wmt_sync(struct hci_dev *hdev, status = BTMTK_WMT_PATCH_DONE; break; case BTMTK_WMT_FUNC_CTRL: - wmt_evt_funcc = (struct btmtk_hci_wmt_evt_funcc *)wmt_evt; + if (!skb_pull_data(data->evt_skb, + sizeof(wmt_evt_funcc->status))) { + err = -EINVAL; + goto err_free_skb; + } + + wmt_evt_funcc = (struct btmtk_hci_wmt_evt_funcc *)wmt_evt; if (be16_to_cpu(wmt_evt_funcc->status) == 0x404) status = BTMTK_WMT_ON_DONE; else if (be16_to_cpu(wmt_evt_funcc->status) == 0x420) -- 2.47.3