NFC: Prevent multiple buffer overflows in NCI

commit 67de956f upstream.

Fix multiple remotely-exploitable stack-based buffer overflows due to
the NCI code pulling length fields directly from incoming frames and
copying too much data into statically-sized arrays.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com>
Cc: security@kernel.org
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Ilan Elias <ilane@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
[bwh: Backported to 3.2:
 - Drop changes to parsing of tech B and tech F parameters
 - Various renaming]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

net/nfc/nci/ntf.c

@@ -86,7 +86,7 @@ static int nci_rf_activate_nfca_passive_poll(struct nci_dev *ndev,
 	nfca_poll->sens_res = __le16_to_cpu(*((__u16 *)data));
 	data += 2;
 
-	nfca_poll->nfcid1_len = *data++;
+	nfca_poll->nfcid1_len = min_t(__u8, *data++, sizeof(nfca_poll->nfcid1));
 
 	nfc_dbg("sens_res 0x%x, nfcid1_len %d",
 		nfca_poll->sens_res,
@@ -111,7 +111,7 @@ static int nci_rf_activate_nfca_passive_poll(struct nci_dev *ndev,
 
 	switch (ntf->rf_interface_type) {
 	case NCI_RF_INTERFACE_ISO_DEP:
-		nfca_poll_iso_dep->rats_res_len = *data++;
+		nfca_poll_iso_dep->rats_res_len = min_t(__u8, *data++, 20);
 		if (nfca_poll_iso_dep->rats_res_len > 0) {
 			memcpy(nfca_poll_iso_dep->rats_res,
 				data,