From 902fe40bce7059722f7ffa1c378e577675cf1918 Mon Sep 17 00:00:00 2001 From: Aurelien DESBRIERES Date: Tue, 21 Apr 2026 15:53:31 +0200 Subject: Bluetooth: hci_uart: Fix NULL deref in recv callbacks when priv is uninitialized When a fault is injected during hci_uart line discipline setup, the proto open() callback may fail leaving hu->priv as NULL. A subsequent TIOCSTI ioctl can trigger the recv() callback before priv is initialized, causing a NULL pointer dereference. Fix all four affected HCI UART protocol drivers by adding a NULL check on hu->priv at the start of their recv() callbacks: h4, h5, ath and bcsp. Reported-by: syzbot+ff30eeab8e07b37d524e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ff30eeab8e07b37d524e Signed-off-by: Aurelien DESBRIERES Assisted-by: Claude:claude-sonnet-4-6 Signed-off-by: Luiz Augusto von Dentz --- drivers/bluetooth/hci_ath.c | 3 +++ drivers/bluetooth/hci_bcsp.c | 3 +++ drivers/bluetooth/hci_h4.c | 3 +++ drivers/bluetooth/hci_h5.c | 3 +++ 4 files changed, 12 insertions(+) diff --git a/drivers/bluetooth/hci_ath.c b/drivers/bluetooth/hci_ath.c index fa679ad0acdf..8201fa7f61e8 100644 --- a/drivers/bluetooth/hci_ath.c +++ b/drivers/bluetooth/hci_ath.c @@ -191,6 +191,9 @@ static int ath_recv(struct hci_uart *hu, const void *data, int count) { struct ath_struct *ath = hu->priv; + if (!ath) + return -ENODEV; + ath->rx_skb = h4_recv_buf(hu, ath->rx_skb, data, count, ath_recv_pkts, ARRAY_SIZE(ath_recv_pkts)); if (IS_ERR(ath->rx_skb)) { diff --git a/drivers/bluetooth/hci_bcsp.c b/drivers/bluetooth/hci_bcsp.c index b386f91d8b46..db56eead27ce 100644 --- a/drivers/bluetooth/hci_bcsp.c +++ b/drivers/bluetooth/hci_bcsp.c @@ -585,6 +585,9 @@ static int bcsp_recv(struct hci_uart *hu, const void *data, int count) if (!test_bit(HCI_UART_REGISTERED, &hu->flags)) return -EUNATCH; + if (!bcsp) + return -ENODEV; + BT_DBG("hu %p count %d rx_state %d rx_count %ld", hu, count, bcsp->rx_state, bcsp->rx_count); diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c index a889a66a326f..767372707498 100644 --- a/drivers/bluetooth/hci_h4.c +++ b/drivers/bluetooth/hci_h4.c @@ -109,6 +109,9 @@ static int h4_recv(struct hci_uart *hu, const void *data, int count) { struct h4_struct *h4 = hu->priv; + if (!h4) + return -ENODEV; + h4->rx_skb = h4_recv_buf(hu, h4->rx_skb, data, count, h4_recv_pkts, ARRAY_SIZE(h4_recv_pkts)); if (IS_ERR(h4->rx_skb)) { diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c index cfdf75dc2847..d35383718212 100644 --- a/drivers/bluetooth/hci_h5.c +++ b/drivers/bluetooth/hci_h5.c @@ -587,6 +587,9 @@ static int h5_recv(struct hci_uart *hu, const void *data, int count) struct h5 *h5 = hu->priv; const unsigned char *ptr = data; + if (!h5) + return -ENODEV; + BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending, count); -- cgit v1.2.3