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Subject[PATCH] nfc: virtual_ncidev: Add variable to check if ndev is running
Date
syzbot reported an memory leak that happens when an skb is add to
send_buff after virtual nci closed.
This patch adds a variable to track if the ndev is running before
handling new skb in send function.

Reported-by: syzbot+6eb09d75211863f15e3e@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/lkml/00000000000075472b06007df4fb@google.com
Signed-off-by: Nguyen Dinh Phi <phind.uet@gmail.com>
---
drivers/nfc/virtual_ncidev.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/nfc/virtual_ncidev.c b/drivers/nfc/virtual_ncidev.c
index b027be0b0b6f..ac8226db54e2 100644
--- a/drivers/nfc/virtual_ncidev.c
+++ b/drivers/nfc/virtual_ncidev.c
@@ -20,26 +20,31 @@
NFC_PROTO_ISO14443_MASK | \
NFC_PROTO_ISO14443_B_MASK | \
NFC_PROTO_ISO15693_MASK)
+#define NCIDEV_RUNNING 0

struct virtual_nci_dev {
struct nci_dev *ndev;
struct mutex mtx;
struct sk_buff *send_buff;
struct wait_queue_head wq;
+ bool running;
};

static int virtual_nci_open(struct nci_dev *ndev)
{
+ struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);
+
+ vdev->running = true;
return 0;
}

static int virtual_nci_close(struct nci_dev *ndev)
{
struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);
-
mutex_lock(&vdev->mtx);
kfree_skb(vdev->send_buff);
vdev->send_buff = NULL;
+ vdev->running = false;
mutex_unlock(&vdev->mtx);

return 0;
@@ -50,7 +55,7 @@ static int virtual_nci_send(struct nci_dev *ndev, struct sk_buff *skb)
struct virtual_nci_dev *vdev = nci_get_drvdata(ndev);

mutex_lock(&vdev->mtx);
- if (vdev->send_buff) {
+ if (vdev->send_buff || !vdev->running) {
mutex_unlock(&vdev->mtx);
kfree_skb(skb);
return -1;
--
2.34.1
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