From e53a7f8afcbd2886f2a94c5d56757328109730ea Mon Sep 17 00:00:00 2001 From: Ryosuke Yasuoka Date: Sun, 19 May 2024 18:43:03 +0900 Subject: 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@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=d7b4dc6cd50410152534 [1] Signed-off-by: Ryosuke Yasuoka Reviewed-by: Krzysztof Kozlowski Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/nfc/nci/core.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'net') diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 5d708af0fcfd..f350c5fb992e 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -1463,6 +1463,19 @@ 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) @@ -1516,7 +1529,7 @@ 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); kcov_remote_stop(); break; -- cgit v1.2.3