From 502adc06ba76dee19c292ae4a07d74d202fe734d Mon Sep 17 00:00:00 2001 From: HyeongJun An Date: Thu, 30 Jul 2026 10:57:28 +0900 Subject: [PATCH] Bluetooth: virtio_bt: avoid OOB read of build info string The virtbt_setup_zephyr() sends the Zephyr vendor command 0xfc08 (Read Build Information) and hands the response to bt_dev_info() and hci_set_fw_info() as a "%s" string starting at skb->data + 1, without checking the length. A backend that answers with status only leaves that pointer past the end of the received data, so the walk reads adjacent slab memory until it meets a NUL. Those bytes reach the kernel log and the firmware-info debugfs file. To fix this, print the string with a bounded "%.*s" limited to skb->len - 1. A short or unterminated response then prints as much as arrived instead of failing setup. This mirrors commit dd068ef04412 ("Bluetooth: bpa10x: avoid OOB read of revision string in bpa10x_setup()"), which fixed the identical pattern. Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver") Signed-off-by: HyeongJun An Assisted-by: Claude:claude-opus-4-8 Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/virtio_bt.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c index 140ab55c9fc5..c20d54088c8c 100644 --- a/drivers/bluetooth/virtio_bt.c +++ b/drivers/bluetooth/virtio_bt.c @@ -120,9 +120,13 @@ static int virtbt_setup_zephyr(struct hci_dev *hdev) if (IS_ERR(skb)) return PTR_ERR(skb); - bt_dev_info(hdev, "%s", (char *)(skb->data + 1)); + /* Bounded print: the backend controls skb->len. */ + if (skb->len > 1) { + int len = skb->len - 1; - hci_set_fw_info(hdev, "%s", skb->data + 1); + bt_dev_info(hdev, "%.*s", len, (char *)(skb->data + 1)); + hci_set_fw_info(hdev, "%.*s", len, skb->data + 1); + } kfree_skb(skb); return 0;