diff mbox series

nfc: st-nci: Fix potential buffer overflows in EVT_TRANSACTION

Message ID 20211117171554.2731340-1-jordy@pwning.systems (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series nfc: st-nci: Fix potential buffer overflows in EVT_TRANSACTION | expand

Checks

Context Check Description
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix warning Target tree name not specified in the subject
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning CHECK: Please don't use multiple blank lines WARNING: line length of 100 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Jordy Zomer Nov. 17, 2021, 5:15 p.m. UTC 
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 :)

Signed-off-by: Jordy Zomer <jordy@pwning.systems>
---
 drivers/nfc/st-nci/se.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

Comments

Jakub Kicinski Nov. 18, 2021, 4:42 a.m. UTC | #1 
On Wed, 17 Nov 2021 18:15:51 +0100 Jordy Zomer wrote:
> +
> +		// Checking if the length of the AID is valid
> +		if (transaction->aid_len > sizeof(transaction->aid))
> +			return -EINVAL;
> +
> +

Please remove the double blank lines and use more common style of
multi-line comments /* */ like the rest of this file.

Same for the other patch. Thanks!
diff mbox series

Patch

diff --git a/drivers/nfc/st-nci/se.c b/drivers/nfc/st-nci/se.c
index 7764b1a4c3cf..0d22853925d8 100644
--- a/drivers/nfc/st-nci/se.c
+++ b/drivers/nfc/st-nci/se.c
@@ -335,6 +335,12 @@  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 +349,15 @@  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);