From f771f96557a4d953a7e4d045870547271e36e819 Mon Sep 17 00:00:00 2001 From: Chandrashekar Devegowda Date: Tue, 22 Sep 2026 12:10:22 +0530 Subject: [PATCH] Bluetooth: btintel_pcie: reject oversized TX packets in send_frame() btintel_pcie_send_frame() eventually copies skb->data into a fixed BTINTEL_PCIE_BUFFER_SIZE (4096) DMA buffer via memcpy() in btintel_pcie_prepare_tx(), with a 4-byte PCIe type header prepended. A user-space process with HCI_CHANNEL_USER access can inject an oversized packet and overflow the buffer. Reject packets larger than BTINTEL_PCIE_BUFFER_SIZE - BTINTEL_PCIE_HCI_TYPE_LEN on entry. Fixes: 6e65a09f9275 ("Bluetooth: btintel_pcie: Add *setup* function to download firmware") Cc: stable@vger.kernel.org Signed-off-by: Chandrashekar Devegowda Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/btintel_pcie.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c index d05af27790f9..f333b01f7465 100644 --- a/drivers/bluetooth/btintel_pcie.c +++ b/drivers/bluetooth/btintel_pcie.c @@ -2219,6 +2219,16 @@ static int btintel_pcie_send_frame(struct hci_dev *hdev, if (test_bit(BTINTEL_PCIE_RECOVERY_IN_PROGRESS, &data->flags)) return -ENODEV; + /* Account for the 4-byte PCIe type header prepended before the + * DMA copy. Written as a subtraction to avoid wrap-around on + * attacker-controlled skb->len. + */ + if (skb->len > BTINTEL_PCIE_BUFFER_SIZE - BTINTEL_PCIE_HCI_TYPE_LEN) { + bt_dev_err(hdev, "Packet too large: %u > %u", skb->len, + BTINTEL_PCIE_BUFFER_SIZE - BTINTEL_PCIE_HCI_TYPE_LEN); + return -EMSGSIZE; + } + /* Due to the fw limitation, the type header of the packet should be * 4 bytes unlike 1 byte for UART. In UART, the firmware can read * the first byte to get the packet type and redirect the rest of data