From c73eb1e0cc5675ebb584b3824b71f5c20ca33fc9 Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 22 Dec 2016 08:19:46 +0100 Subject: xen: xenbus driver must not accept invalid transaction ids [ Upstream commit 639b08810d6ad74ded2c5f6e233c4fcb9d147168 ] When accessing Xenstore in a transaction the user is specifying a transaction id which he normally obtained from Xenstore when starting the transaction. Xenstore is validating a transaction id against all known transaction ids of the connection the request came in. As all requests of a domain not being the one where Xenstore lives share one connection, validation of transaction ids of different users of Xenstore in that domain should be done by the kernel of that domain being the multiplexer between the Xenstore users in that domain and Xenstore. In order to prohibit one Xenstore user "hijacking" a transaction from another user the xenbus driver has to verify a given transaction id against all known transaction ids of the user before forwarding it to Xenstore. Signed-off-by: Juergen Gross Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 0e0eb10f82a0..816a0e08ef10 100644 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -316,7 +316,7 @@ static int xenbus_write_transaction(unsigned msg_type, rc = -ENOMEM; goto out; } - } else if (msg_type == XS_TRANSACTION_END) { + } else if (u->u.msg.tx_id != 0) { list_for_each_entry(trans, &u->transactions, list) if (trans->handle.id == u->u.msg.tx_id) break; -- cgit v1.2.3