From 0ad6bded175e829c2ca261529c9dce39a32a042d Mon Sep 17 00:00:00 2001 From: Lin Ma Date: Wed, 16 Nov 2022 21:02:49 +0800 Subject: nfc/nci: fix race with opening and closing Previously we leverage NCI_UNREG and the lock inside nci_close_device to prevent the race condition between opening a device and closing a device. However, it still has problem because a failed opening command will erase the NCI_UNREG flag and allow another opening command to bypass the status checking. This fix corrects that by making sure the NCI_UNREG is held. Reported-by: syzbot+43475bf3cfbd6e41f5b7@syzkaller.appspotmail.com Fixes: 48b71a9e66c2 ("NFC: add NCI_UNREG flag to eliminate the race") Signed-off-by: Lin Ma Signed-off-by: David S. Miller --- net/nfc/nci/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/nfc') diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index 6a193cce2a75..4ffdf2f45c44 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -542,7 +542,7 @@ static int nci_open_device(struct nci_dev *ndev) skb_queue_purge(&ndev->tx_q); ndev->ops->close(ndev); - ndev->flags = 0; + ndev->flags &= BIT(NCI_UNREG); } done: -- cgit