From 453de21c2b8281228173a7b689120b92929743d6 Mon Sep 17 00:00:00 2001 From: Andres Beltran Date: Mon, 9 Nov 2020 11:04:01 +0100 Subject: [PATCH] scsi: storvsc: Use vmbus_requestor to generate transaction IDs for VMBus hardening Currently, pointers to guest memory are passed to Hyper-V as transaction IDs in storvsc. In the face of errors or malicious behavior in Hyper-V, storvsc should not expose or trust the transaction IDs returned by Hyper-V to be valid guest memory addresses. Instead, use small integers generated by vmbus_requestor as requests (transaction) IDs. Signed-off-by: Andres Beltran Co-developed-by: Andrea Parri (Microsoft) Signed-off-by: Andrea Parri (Microsoft) Reviewed-by: Michael Kelley Cc: "James E.J. Bottomley" Cc: "Martin K. Petersen" Cc: linux-scsi@vger.kernel.org Link: https://lore.kernel.org/r/20201109100402.8946-3-parri.andrea@gmail.com Acked-by: Martin K. Petersen Reviewed-by: Wei Liu Signed-off-by: Wei Liu --- drivers/scsi/storvsc_drv.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 0c65fbd41035..369a6c626672 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -399,6 +399,7 @@ static int storvsc_timeout = 180; static struct scsi_transport_template *fc_transport_template; #endif +static struct scsi_host_template scsi_driver; static void storvsc_on_channel_callback(void *context); #define STORVSC_MAX_LUNS_PER_TARGET 255 @@ -698,6 +699,12 @@ static void handle_sc_creation(struct vmbus_channel *new_sc) memset(&props, 0, sizeof(struct vmstorage_channel_properties)); + /* + * The size of vmbus_requestor is an upper bound on the number of requests + * that can be in-progress at any one time across all channels. + */ + new_sc->rqstor_size = scsi_driver.can_queue; + ret = vmbus_open(new_sc, storvsc_ringbuffer_size, storvsc_ringbuffer_size, @@ -1242,9 +1249,17 @@ static void storvsc_on_channel_callback(void *context) foreach_vmbus_pkt(desc, channel) { void *packet = hv_pkt_data(desc); struct storvsc_cmd_request *request; + u64 cmd_rqst; - request = (struct storvsc_cmd_request *) - ((unsigned long)desc->trans_id); + cmd_rqst = vmbus_request_addr(&channel->requestor, + desc->trans_id); + if (cmd_rqst == VMBUS_RQST_ERROR) { + dev_err(&device->device, + "Incorrect transaction id\n"); + continue; + } + + request = (struct storvsc_cmd_request *)(unsigned long)cmd_rqst; if (request == &stor_device->init_request || request == &stor_device->reset_request) { @@ -1265,6 +1280,12 @@ static int storvsc_connect_to_vsp(struct hv_device *device, u32 ring_size, memset(&props, 0, sizeof(struct vmstorage_channel_properties)); + /* + * The size of vmbus_requestor is an upper bound on the number of requests + * that can be in-progress at any one time across all channels. + */ + device->channel->rqstor_size = scsi_driver.can_queue; + ret = vmbus_open(device->channel, ring_size, ring_size, @@ -1572,7 +1593,6 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd) struct vstor_packet *vstor_packet; int ret, t; - stor_device = get_out_stor_device(device); if (!stor_device) return FAILED;