From 84c24fb151fc1179355296d7ff29129ac7c42129 Mon Sep 17 00:00:00 2001 From: David Carlier Date: Fri, 15 May 2026 07:25:25 +0100 Subject: [PATCH] Bluetooth: ISO: drop ISO_END frames received without prior ISO_START ISO data PDUs carry a packet-boundary flag indicating START, CONT, END or SINGLE. The ISO_CONT branch of iso_recv() guards against a missing ISO_START by checking conn->rx_len before touching conn->rx_skb, but ISO_END does not. If a peer sends an ISO_END as the first packet on a fresh ISO connection, conn->rx_skb is still NULL and conn->rx_len is zero, so skb_put(conn->rx_skb, ...) dereferences NULL and oopses. For BIS, where receivers sync to a broadcaster without pairing, any broadcaster on the air can trigger this. Mirror the ISO_CONT check at the top of ISO_END so a stray end fragment is logged and dropped instead of crashing the host. Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-7 Signed-off-by: David Carlier Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/iso.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index 7cb2864fe872..b971281f0a2b 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -2593,6 +2593,11 @@ int iso_recv(struct hci_dev *hdev, u16 handle, struct sk_buff *skb, u16 flags) break; case ISO_END: + if (!conn->rx_len) { + BT_ERR("Unexpected end frame (len %d)", skb->len); + goto drop; + } + skb_copy_from_linear_data(skb, skb_put(conn->rx_skb, skb->len), skb->len); conn->rx_len -= skb->len;