Bluetooth: hci_uart: Check if socket buffer is ERR_PTR in h4_recv_buf()

h4_recv_buf() callers store the return value to socket buffer and
recursively pass the buffer to h4_recv_buf() without protection. So,
ERR_PTR returned from h4_recv_buf() can be dereferenced, if called again
before setting the socket buffer to NULL from previous error. Check if
skb is ERR_PTR in h4_recv_buf().

Reported-by: syzbot+017a32f149406df32703@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

diff --git a/drivers/bluetooth/h4_recv.h b/drivers/bluetooth/h4_recv.h
index b432651..307d821 100644 (file)
--- a/drivers/bluetooth/h4_recv.h
+++ b/drivers/bluetooth/h4_recv.h
@@ -60,6 +60,10 @@ static inline struct sk_buff *h4_recv_buf(struct hci_dev *hdev,
                                          const struct h4_recv_pkt *pkts,
                                          int pkts_count)
 {
+       /* Check for error from previous call */
+       if (IS_ERR(skb))
+               skb = NULL;
+
        while (count) {
                int i, len;
 

diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c
index fb97a3b..5d97d77 100644 (file)
--- a/drivers/bluetooth/hci_h4.c
+++ b/drivers/bluetooth/hci_h4.c
@@ -174,6 +174,10 @@ struct sk_buff *h4_recv_buf(struct hci_dev *hdev, struct sk_buff *skb,
        struct hci_uart *hu = hci_get_drvdata(hdev);
        u8 alignment = hu->alignment ? hu->alignment : 1;
 
+       /* Check for error from previous call */
+       if (IS_ERR(skb))
+               skb = NULL;
+
        while (count) {
                int i, len;