nfc: digital: clamp SENSF_RES length to the destination buffer

commit 344a56d upstream.

digital_in_recv_sensf_res() memcpy()s resp->len bytes from a remote
NFC-F device response into the NFC_SENSF_RES_MAXSIZE-byte target.sensf_res
field without an upper-bound check. A nearby malicious NFC-F device can
send an oversized SENSF_RES response to overflow the stack-local struct
nfc_target.

Clamp resp->len to NFC_SENSF_RES_MAXSIZE before the copy.

Found by 0sec automated security-research tooling (https://0sec.ai).

Fixes: 8c0695e ("NFC Digital: Add NFC-F technology support")
Cc: stable@vger.kernel.org
Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai>
Reviewed-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Link: https://patch.msgid.link/20260603141355.68156-1-doruk@0sec.ai
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: peaktwilight

net/nfc/digital_technology.c

@@ -778,6 +778,8 @@ static void digital_in_recv_sensf_res(struct nfc_digital_dev *ddev, void *arg,
 
 	sensf_res = (struct digital_sensf_res *)resp->data;
 
+	resp->len = min_t(unsigned int, resp->len, NFC_SENSF_RES_MAXSIZE);
+
 	memcpy(target.sensf_res, sensf_res, resp->len);
 	target.sensf_res_len = resp->len;