From: Myungho Jung <mhjungk@gmail.com>
Date: Tue, 22 Jan 2019 08:33:26 +0000 (-0800)
Subject: Bluetooth: hci_uart: Check if socket buffer is ERR_PTR in h4_recv_buf()
X-Git-Tag: v4.14.109~22
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=86384a1fa3e5389e58d8a6673ed09143abe1354e;p=users%2Fjedix%2Flinux-maple.git

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

commit 1dc2d785156cbdc80806c32e8d2c7c735d0b4721 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/bluetooth/hci_h4.c b/drivers/bluetooth/hci_h4.c
index 3b82a87224a9..d428117c97c3 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;