From 1dc2d785156cbdc80806c32e8d2c7c735d0b4721 Mon Sep 17 00:00:00 2001 From: Myungho Jung Date: Tue, 22 Jan 2019 00:33:26 -0800 Subject: [PATCH] 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 Signed-off-by: Marcel Holtmann --- drivers/bluetooth/h4_recv.h | 4 ++++ drivers/bluetooth/hci_h4.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/drivers/bluetooth/h4_recv.h b/drivers/bluetooth/h4_recv.h index b432651f8236..307d82166f48 100644 --- 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 fb97a3bf069b..5d97d77627c1 100644 --- 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;