From: Juergen Gross Date: Thu, 22 Dec 2016 07:19:46 +0000 (+0100) Subject: xen: xenbus driver must not accept invalid transaction ids X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=639b08810d6ad74ded2c5f6e233c4fcb9d147168;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git xen: xenbus driver must not accept invalid transaction ids 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 --- diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index 6c0ead4be784..a06828124b70 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;