Messages in this thread Patch in this message | | | From | Ryosuke Yasuoka <> | Subject | [PATCH net v2] nfc: nci: Fix uninit-value in nci_rx_work | Date | Sat, 27 Apr 2024 19:35:54 +0900 |
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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 <ryasuoka@redhat.com> --- v2 - The v1 patch only checked whether skb->len is zero. This patch also checks header size, payload size and total packet size.
v1 https://lore.kernel.org/linux-kernel/CANn89iJrQevxPFLCj2P=U+XSisYD0jqrUQpa=zWMXTjj5+RriA@mail.gmail.com/T/
net/nfc/nci/core.c | 28 ++++++++++++++++++++++------ 1 file changed, 22 insertions(+), 6 deletions(-)
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 0d26c8ec9993..ab07b5f69664 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -1463,6 +1463,16 @@ 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, unsigned int header_size) +{ + if (skb->len < header_size || + !nci_plen(skb->data) || + skb->len < header_size + nci_plen(skb->data)) { + return false; + } + return true; +} + /* ---- NCI TX Data worker thread ---- */ static void nci_tx_work(struct work_struct *work) @@ -1516,30 +1526,36 @@ 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; - } + if (!skb->len) + goto invalid_pkt_free; /* Process frame */ switch (nci_mt(skb->data)) { case NCI_MT_RSP_PKT: + if (!nci_valid_size(skb, NCI_CTRL_HDR_SIZE)) + goto invalid_pkt_free; nci_rsp_packet(ndev, skb); break; case NCI_MT_NTF_PKT: + if (!nci_valid_size(skb, NCI_CTRL_HDR_SIZE)) + goto invalid_pkt_free; nci_ntf_packet(ndev, skb); break; case NCI_MT_DATA_PKT: + if (!nci_valid_size(skb, NCI_DATA_HDR_SIZE)) + goto invalid_pkt_free; nci_rx_data_packet(ndev, skb); break; default: pr_err("unknown MT 0x%x\n", nci_mt(skb->data)); - kfree_skb(skb); - break; + goto invalid_pkt_free; } +invalid_pkt_free: + kfree_skb(skb); + break; } /* check if a data exchange timeout has occurred */ -- 2.44.0
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