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| author | Juergen Gross <jgross@suse.com> | 2022-02-25 16:05:41 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-03-11 10:15:13 +0100 |
| commit | 927e4eb8ddf4968b6a33be992b28063f84552c72 (patch) | |
| tree | 6f0ff3b916f6f7819bc5e71275d54a8fe127db1d /drivers/net | |
| parent | 423a3a50dce9a48d10d2d2a70cd2f78064c13703 (diff) | |
| download | linux-stable-927e4eb8ddf4968b6a33be992b28063f84552c72.tar.gz linux-stable-927e4eb8ddf4968b6a33be992b28063f84552c72.tar.bz2 linux-stable-927e4eb8ddf4968b6a33be992b28063f84552c72.zip | |
xen/netfront: don't use gnttab_query_foreign_access() for mapped status
Commit 31185df7e2b1d2fa1de4900247a12d7b9c7087eb upstream.
It isn't enough to check whether a grant is still being in use by
calling gnttab_query_foreign_access(), as a mapping could be realized
by the other side just after having called that function.
In case the call was done in preparation of revoking a grant it is
better to do so via gnttab_end_foreign_access_ref() and check the
success of that operation instead.
This is CVE-2022-23037 / part of XSA-396.
Reported-by: Demi Marie Obenour <demi@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/xen-netfront.c | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 7fb7c10ff9eb..fddfa93d8d47 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -414,14 +414,12 @@ static bool xennet_tx_buf_gc(struct netfront_queue *queue) queue->tx_link[id] = TX_LINK_NONE; skb = queue->tx_skbs[id]; queue->tx_skbs[id] = NULL; - if (unlikely(gnttab_query_foreign_access( - queue->grant_tx_ref[id]) != 0)) { + if (unlikely(!gnttab_end_foreign_access_ref( + queue->grant_tx_ref[id], GNTMAP_readonly))) { dev_alert(dev, "Grant still in use by backend domain\n"); goto err; } - gnttab_end_foreign_access_ref( - queue->grant_tx_ref[id], GNTMAP_readonly); gnttab_release_grant_reference( &queue->gref_tx_head, queue->grant_tx_ref[id]); queue->grant_tx_ref[id] = GRANT_INVALID_REF; |