Patch "nfc: nci: Fix uninit-value in nci_rx_work" has been added to the 4.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    nfc: nci: Fix uninit-value in nci_rx_work

to the 4.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     nfc-nci-fix-uninit-value-in-nci_rx_work.patch
and it can be found in the queue-4.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit e5dc3f234d579f80e220e5ede3937c6fc9c1245d
Author: Ryosuke Yasuoka <ryasuoka@xxxxxxxxxx>
Date:   Sun May 19 18:43:03 2024 +0900

    nfc: nci: Fix uninit-value in nci_rx_work
    
    [ Upstream commit e4a87abf588536d1cdfb128595e6e680af5cf3ed ]
    
    syzbot reported the following uninit-value access issue [1]
    
    nci_rx_work() parses received packet from ndev->rx_q. It should be
    validated header size, payload size and total packet size before
    processing the packet. If an invalid packet is detected, it should be
    silently discarded.
    
    Fixes: d24b03535e5e ("nfc: nci: Fix uninit-value in nci_dev_up and nci_ntf_packet")
    Reported-and-tested-by: syzbot+d7b4dc6cd50410152534@xxxxxxxxxxxxxxxxxxxxxxxxx
    Closes: https://syzkaller.appspot.com/bug?extid=d7b4dc6cd50410152534 [1]
    Signed-off-by: Ryosuke Yasuoka <ryasuoka@xxxxxxxxxx>
    Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 1f863ccf21211..6e83159b7b436 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -1461,6 +1461,19 @@ int nci_core_ntf_packet(struct nci_dev *ndev, __u16 opcode,
 				 ndev->ops->n_core_ops);
 }
 
+static bool nci_valid_size(struct sk_buff *skb)
+{
+	BUILD_BUG_ON(NCI_CTRL_HDR_SIZE != NCI_DATA_HDR_SIZE);
+	unsigned int hdr_size = NCI_CTRL_HDR_SIZE;
+
+	if (skb->len < hdr_size ||
+	    !nci_plen(skb->data) ||
+	    skb->len < hdr_size + nci_plen(skb->data)) {
+		return false;
+	}
+	return true;
+}
+
 /* ---- NCI TX Data worker thread ---- */
 
 static void nci_tx_work(struct work_struct *work)
@@ -1511,7 +1524,7 @@ 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)) {
+		if (!nci_valid_size(skb)) {
 			kfree_skb(skb);
 			break;
 		}