nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet

syzbot reported the following uninit-value access issue [1][2]:

nci_rx_work() parses and processes received packet. When the payload
length is zero, each message type handler reads uninitialized payload
and KMSAN detects this issue. The receipt of a packet with a zero-size
payload is considered unexpected, and therefore, such packets should be
silently discarded.

This patch resolved this issue by checking payload size before calling
each message type handler codes.

Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation")
Reported-and-tested-by: syzbot+7ea9413ea6749baf5574@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+29b5ca705d2e0f4a44d2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7ea9413ea6749baf5574 [1]
Closes: https://syzkaller.appspot.com/bug?extid=29b5ca705d2e0f4a44d2 [2]
Signed-off-by: Ryosuke Yasuoka <ryasuoka@redhat.com>
Reviewed-by: Jeremy Cline <jeremy@jcline.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index cdad47b140fa4bd54ac0571457ab16ab505a3a11..0d26c8ec9993ea18af0beeeff5ac1a8cd3ef72f6 100644 (file)
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -1516,6 +1516,11 @@ static void nci_rx_work(struct work_struct *work)
                nfc_send_to_raw_sock(ndev->nfc_dev, skb,
                                     RAW_PAYLOAD_NCI, NFC_DIRECTION_RX);
 
+               if (!nci_plen(skb->data)) {
+                       kfree_skb(skb);
+                       break;
+               }
+
                /* Process frame */
                switch (nci_mt(skb->data)) {
                case NCI_MT_RSP_PKT: