Bluetooth: Check minimum length of SMP packets

When SMP packets are received, make sure they contain at least 1 byte
header for the opcode. If not, drop the packet and disconnect the link.

Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 6e0494971db1..884b2081a262 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -848,8 +848,7 @@ static int smp_cmd_master_ident(struct l2cap_conn *conn, struct sk_buff *skb)
 int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
 {
         struct hci_conn *hcon = conn->hcon;
-        __u8 code = skb->data[0];
-        __u8 reason;
+        __u8 code, reason;
         int err = 0;
 
         if (hcon->type != LE_LINK) {
@@ -857,12 +856,18 @@ int smp_sig_channel(struct l2cap_conn *conn, struct sk_buff *skb)
                 return -ENOTSUPP;
         }
 
+        if (skb->len < 1) {
+                kfree_skb(skb);
+                return -EILSEQ;
+        }
+
         if (!test_bit(HCI_LE_ENABLED, &conn->hcon->hdev->dev_flags)) {
                 err = -ENOTSUPP;
                 reason = SMP_PAIRING_NOTSUPP;
                 goto done;
         }
 
+        code = skb->data[0];
         skb_pull(skb, sizeof(code));
 
         /*