This is a note to let you know that I've just added the patch titled
nfc/nci: fix race with opening and closing
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfc-nci-fix-race-with-opening-and-closing.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit a2e1513f0d1c12b022615bc84357576bd480f1ba
Author: Lin Ma <linma@xxxxxxxxxx>
Date: Wed Nov 16 21:02:49 2022 +0800
nfc/nci: fix race with opening and closing
[ 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 48b71a9e66c2 ("NFC: add NCI_UNREG flag to eliminate the race")
Signed-off-by: Lin Ma <linma@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index b2e922fcc70d..57849baf9294 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -530,7 +530,7 @@ 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:
