[PATCH v2] nfc: st-nci: Fix potential buffer overflows in EVT_TRANSACTION
From: Jordy Zomer <hidden>
Date: 2021-11-18 07:02:30
Also in:
lkml
Subsystem:
nfc subsystem, the rest · Maintainers:
David Heidelberg, Linus Torvalds
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. It would be nice if someone can review and test this patch because I don't own the hardware :) EDIT: Changed comment style and double newlines Signed-off-by: Jordy Zomer <redacted> --- drivers/nfc/st-nci/se.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c
index 7764b1a4c3cf..8e2ac8a3d199 100644
--- a/drivers/nfc/st-nci/se.c
+++ b/drivers/nfc/st-nci/se.c@@ -335,6 +335,11 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, 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); /* Check next byte is PARAMETERS tag (82) */
@@ -343,6 +348,16 @@ static int st_nci_hci_connectivity_event_received(struct nci_dev *ndev, return -EPROTO; transaction->params_len = skb->data[transaction->aid_len + 3]; + + /* + * check if the length of the parameters is valid + * we can't use sizeof(transaction->params) because it's + * a flexible array member so we have to check if params_len + * is bigger than the space allocated for the array + */ + 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);
--
2.27.0