From: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx> This fixes not checking if skb really contains an ACL header otherwise the code may attempt to access some uninitilized/invalid memory past the valid skb->data. Reported-by: syzbot+6ea290ba76d8c1eb1ac2@xxxxxxxxxxxxxxxxxxxxxxxxx Tested-by: syzbot+6ea290ba76d8c1eb1ac2@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=6ea290ba76d8c1eb1ac2 Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@xxxxxxxxx> --- net/bluetooth/hci_core.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index b2f8f9c5b610..d5f917076e0e 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -3765,18 +3765,22 @@ static void hci_tx_work(struct work_struct *work) /* ACL data packet */ static void hci_acldata_packet(struct hci_dev *hdev, struct sk_buff *skb) { - struct hci_acl_hdr *hdr = (void *) skb->data; + struct hci_acl_hdr *hdr; struct hci_conn *conn; __u16 handle, flags; - skb_pull(skb, HCI_ACL_HDR_SIZE); + hdr = skb_pull_data(skb, sizeof(*hdr)); + if (!hdr) { + bt_dev_err(hdev, "ACL packet too small"); + goto drop; + } handle = __le16_to_cpu(hdr->handle); flags = hci_flags(handle); handle = hci_handle(handle); - BT_DBG("%s len %d handle 0x%4.4x flags 0x%4.4x", hdev->name, skb->len, - handle, flags); + bt_dev_dbg(hdev, "len %d handle 0x%4.4x flags 0x%4.4x", skb->len, + handle, flags); hdev->stat.acl_rx++; @@ -3797,6 +3801,7 @@ static void hci_acldata_packet(struct hci_dev *hdev, struct sk_buff *skb) handle); } +drop: kfree_skb(skb); } -- 2.46.2
