diff options
| author | Michael Bommarito <michael.bommarito@gmail.com> | 2026-04-21 13:08:45 -0400 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2026-05-06 16:22:33 -0400 |
| commit | daf23014e5d975e72ea9c02b5160d3fcf070ea47 (patch) | |
| tree | 83e06248e1d3b9adc9c15d5f95983cc274a7855a | |
| parent | 21bd244b6de5d2fe1063c23acc93fbdd2b20d112 (diff) | |
Bluetooth: virtio_bt: validate rx pkt_type header length
virtbt_rx_handle() reads the leading pkt_type byte from the RX skb
and forwards the remainder to hci_recv_frame() for every
event/ACL/SCO/ISO type, without checking that the remaining payload
is at least the fixed HCI header for that type.
After the preceding patch bounds the backend-supplied used.len to
[1, VIRTBT_RX_BUF_SIZE], a one-byte completion still reaches
hci_recv_frame() with skb->len already pulled to 0. If the byte
happened to be HCI_ACLDATA_PKT, the ACL-vs-ISO classification
fast-path in hci_dev_classify_pkt_type() dereferences
hci_acl_hdr(skb)->handle whenever the HCI device has an active
CIS_LINK, BIS_LINK, or PA_LINK connection, reading two bytes of
uninitialized RX-buffer data. The same hazard exists for every
packet type the driver accepts because none of the switch cases in
virtbt_rx_handle() check skb->len against the per-type minimum HCI
header size before handing the frame to the core.
After stripping pkt_type, require skb->len to cover the fixed
header size for the selected type (event 2, ACL 4, SCO 3, ISO 4)
before calling hci_recv_frame(); drop ratelimited otherwise.
Unknown pkt_type values still take the original kfree_skb() default
path.
Use bt_dev_err_ratelimited() because both the length and pkt_type
values come from an untrusted backend that can otherwise flood the
kernel log.
Fixes: 160fbcf3bfb9 ("Bluetooth: virtio_bt: Use skb_put to set length")
Cc: stable@vger.kernel.org
Cc: Soenke Huster <soenke.huster@eknoes.de>
Signed-off-by: Michael Bommarito <michael.bommarito@gmail.com>
Assisted-by: Claude:claude-opus-4-7
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
| -rw-r--r-- | drivers/bluetooth/virtio_bt.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c index 2c5c39356a1c..140ab55c9fc5 100644 --- a/drivers/bluetooth/virtio_bt.c +++ b/drivers/bluetooth/virtio_bt.c @@ -198,6 +198,7 @@ static int virtbt_shutdown_generic(struct hci_dev *hdev) static void virtbt_rx_handle(struct virtio_bluetooth *vbt, struct sk_buff *skb) { + size_t min_hdr; __u8 pkt_type; pkt_type = *((__u8 *) skb->data); @@ -205,16 +206,32 @@ static void virtbt_rx_handle(struct virtio_bluetooth *vbt, struct sk_buff *skb) switch (pkt_type) { case HCI_EVENT_PKT: + min_hdr = sizeof(struct hci_event_hdr); + break; case HCI_ACLDATA_PKT: + min_hdr = sizeof(struct hci_acl_hdr); + break; case HCI_SCODATA_PKT: + min_hdr = sizeof(struct hci_sco_hdr); + break; case HCI_ISODATA_PKT: - hci_skb_pkt_type(skb) = pkt_type; - hci_recv_frame(vbt->hdev, skb); + min_hdr = sizeof(struct hci_iso_hdr); break; default: kfree_skb(skb); - break; + return; } + + if (skb->len < min_hdr) { + bt_dev_err_ratelimited(vbt->hdev, + "rx pkt_type 0x%02x payload %u < hdr %zu\n", + pkt_type, skb->len, min_hdr); + kfree_skb(skb); + return; + } + + hci_skb_pkt_type(skb) = pkt_type; + hci_recv_frame(vbt->hdev, skb); } static void virtbt_rx_work(struct work_struct *work) |