From: Lin Ma linma@zju.edu.cn
[ Upstream commit 0ad6bded175e829c2ca261529c9dce39a32a042d ]
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 linma@zju.edu.cn Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/nfc/nci/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c index df90872fcf90..e7701c36f36c 100644 --- a/net/nfc/nci/core.c +++ b/net/nfc/nci/core.c @@ -543,7 +543,7 @@ 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: