netdev - [PATCH net] net: nfc: fix bounds checking bugs on "pipe"

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Message-ID: <20200304142429.2734khtbfyyoxmwc@kili.mountain>
Date:   Wed, 4 Mar 2020 17:24:31 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     "David S. Miller" <davem@...emloft.net>,
        Christophe Ricard <christophe.ricard@...il.com>
Cc:     Jakub Kicinski <kuba@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Allison Randal <allison@...utok.net>, netdev@...r.kernel.org,
        Suren Baghdasaryan <surenb@...gle.com>,
        kernel-janitors@...r.kernel.org
Subject: [PATCH net] net: nfc: fix bounds checking bugs on "pipe"

This is similar to commit 674d9de02aa7 ("NFC: Fix possible memory
corruption when handling SHDLC I-Frame commands") and commit d7ee81ad09f0
("NFC: nci: Add some bounds checking in nci_hci_cmd_received()") which
added range checks on "pipe".

The "pipe" variable comes skb->data[0] in nfc_hci_msg_rx_work().
It's in the 0-255 range.  We're using it as the array index into the
hdev->pipes[] array which has NFC_HCI_MAX_PIPES (128) members.

Fixes: 118278f20aa8 ("NFC: hci: Add pipes table to reference them with a tuple {gate, host}")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 net/nfc/hci/core.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 6f1b096e601c..43811b5219b5 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -181,13 +181,20 @@ void nfc_hci_resp_received(struct nfc_hci_dev *hdev, u8 result,
 void nfc_hci_cmd_received(struct nfc_hci_dev *hdev, u8 pipe, u8 cmd,
 			  struct sk_buff *skb)
 {
-	u8 gate = hdev->pipes[pipe].gate;
 	u8 status = NFC_HCI_ANY_OK;
 	struct hci_create_pipe_resp *create_info;
 	struct hci_delete_pipe_noti *delete_info;
 	struct hci_all_pipe_cleared_noti *cleared_info;
+	u8 gate;
 
-	pr_debug("from gate %x pipe %x cmd %x\n", gate, pipe, cmd);
+	pr_debug("from pipe %x cmd %x\n", pipe, cmd);
+
+	if (pipe >= NFC_HCI_MAX_PIPES) {
+		status = NFC_HCI_ANY_E_NOK;
+		goto exit;
+	}
+
+	gate = hdev->pipes[pipe].gate;
 
 	switch (cmd) {
 	case NFC_HCI_ADM_NOTIFY_PIPE_CREATED:
@@ -375,8 +382,14 @@ void nfc_hci_event_received(struct nfc_hci_dev *hdev, u8 pipe, u8 event,
 			    struct sk_buff *skb)
 {
 	int r = 0;
-	u8 gate = hdev->pipes[pipe].gate;
+	u8 gate;
+
+	if (pipe >= NFC_HCI_MAX_PIPES) {
+		pr_err("Discarded event %x to invalid pipe %x\n", event, pipe);
+		goto exit;
+	}
 
+	gate = hdev->pipes[pipe].gate;
 	if (gate == NFC_HCI_INVALID_GATE) {
 		pr_err("Discarded event %x to unopened pipe %x\n", event, pipe);
 		goto exit;
-- 
2.11.0