Skip to content
Permalink
Browse files Browse the repository at this point in the history
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>
  • Loading branch information
JordyZomer authored and davem330 committed Jan 12, 2022
1 parent 2a4d75b commit 4fbcc1a
Showing 1 changed file with 10 additions and 0 deletions.
10 changes: 10 additions & 0 deletions drivers/nfc/st21nfca/se.c
Expand Up @@ -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);

Expand All @@ -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);

Expand Down

0 comments on commit 4fbcc1a

Please sign in to comment.