releases/5.0.5/bluetooth-hci_uart-check-if-socket-buffer-is-err_ptr-in-h4_recv_buf.patch

   1 From 1dc2d785156cbdc80806c32e8d2c7c735d0b4721 Mon Sep 17 00:00:00 2001
   2 From: Myungho Jung <mhjungk@gmail.com>
   3 Date: Tue, 22 Jan 2019 00:33:26 -0800
   4 Subject: Bluetooth: hci_uart: Check if socket buffer is ERR_PTR in h4_recv_buf()
   5
   6 From: Myungho Jung <mhjungk@gmail.com>
   7
   8 commit 1dc2d785156cbdc80806c32e8d2c7c735d0b4721 upstream.
   9
  10 h4_recv_buf() callers store the return value to socket buffer and
  11 recursively pass the buffer to h4_recv_buf() without protection. So,
  12 ERR_PTR returned from h4_recv_buf() can be dereferenced, if called again
  13 before setting the socket buffer to NULL from previous error. Check if
  14 skb is ERR_PTR in h4_recv_buf().
  15
  16 Reported-by: syzbot+017a32f149406df32703@syzkaller.appspotmail.com
  17 Signed-off-by: Myungho Jung <mhjungk@gmail.com>
  18 Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20
  21 ---
  22  drivers/bluetooth/h4_recv.h |    4 ++++
  23  drivers/bluetooth/hci_h4.c  |    4 ++++
  24  2 files changed, 8 insertions(+)
  25
  26 --- a/drivers/bluetooth/h4_recv.h
  27 +++ b/drivers/bluetooth/h4_recv.h
  28 @@ -60,6 +60,10 @@ static inline struct sk_buff *h4_recv_bu
  29                                           const struct h4_recv_pkt *pkts,
  30                                           int pkts_count)
  31  {
  32 +       /* Check for error from previous call */
  33 +       if (IS_ERR(skb))
  34 +               skb = NULL;
  35 +
  36         while (count) {
  37                 int i, len;
  38
  39 --- a/drivers/bluetooth/hci_h4.c
  40 +++ b/drivers/bluetooth/hci_h4.c
  41 @@ -174,6 +174,10 @@ struct sk_buff *h4_recv_buf(struct hci_d
  42         struct hci_uart *hu = hci_get_drvdata(hdev);
  43         u8 alignment = hu->alignment ? hu->alignment : 1;
  44
  45 +       /* Check for error from previous call */
  46 +       if (IS_ERR(skb))
  47 +               skb = NULL;
  48 +
  49         while (count) {
  50                 int i, len;
  51