nfc: st21nfca: Fix potential buffer overflows in EVT_TRANSACTION

It appears that there are some buffer overflows in EVT_TRANSACTION.
This happens because the length parameters that are passed to memcpy
come directly from skb->data and are not guarded in any way.

Signed-off-by: Jordy Zomer <jordy@pwning.systems>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Jordy Zomer 2022-01-11 17:44:51 +01:00 committed by David S. Miller
parent 2a4d75bfe4
commit 4fbcc1a4cb

View File

@ -316,6 +316,11 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
return -ENOMEM;
transaction->aid_len = skb->data[1];
/* Checking if the length of the AID is valid */
if (transaction->aid_len > sizeof(transaction->aid))
return -EINVAL;
memcpy(transaction->aid, &skb->data[2],
transaction->aid_len);
@ -325,6 +330,11 @@ int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
return -EPROTO;
transaction->params_len = skb->data[transaction->aid_len + 3];
/* Total size is allocated (skb->len - 2) minus fixed array members */
if (transaction->params_len > ((skb->len - 2) - sizeof(struct nfc_evt_transaction)))
return -EINVAL;
memcpy(transaction->params, skb->data +
transaction->aid_len + 4, transaction->params_len);