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.
Cc: "James E.J. Bottomley" <j...@linux.ibm.com> Cc: "Martin K. Petersen" <martin.peter...@oracle.com> Cc: linux-s...@vger.kernel.org Signed-off-by: Andres Beltran <lkmlab...@gmail.com> Reviewed-by: Michael Kelley <mikel...@microsoft.com> Tested-by: Andrea Parri <parri.and...@gmail.com> Acked-by: Martin K. Petersen <martin.peter...@oracle.com> Link: https://lore.kernel.org/r/20200701001221.2540-3-lkmlab...@gmail.com Signed-off-by: Wei Liu <wei....@kernel.org> --- Changes in v2: - Add casts to unsigned long to fix warnings on 32bit. drivers/scsi/storvsc_drv.c | 85 +++++++++++++++++++++++++++++++++----- 1 file changed, 74 insertions(+), 11 deletions(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 624467e2590a..6d2df1f0fe6d 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, @@ -726,6 +733,7 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) struct storvsc_cmd_request *request; struct vstor_packet *vstor_packet; int ret, t; + u64 rqst_id; /* * If the number of CPUs is artificially restricted, such as @@ -760,14 +768,23 @@ static void handle_multichannel_storage(struct hv_device *device, int max_chns) vstor_packet->flags = REQUEST_COMPLETION_FLAG; vstor_packet->sub_channel_count = num_sc; + rqst_id = vmbus_next_request_id(&device->channel->requestor, + (unsigned long)request); + if (rqst_id == VMBUS_RQST_ERROR) { + dev_err(dev, "No request id available\n"); + return; + } + ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - vmscsi_size_delta), - (unsigned long)request, + rqst_id, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); if (ret != 0) { + /* Reclaim request ID to avoid leak of IDs */ + vmbus_request_addr(&device->channel->requestor, rqst_id); dev_err(dev, "Failed to create sub-channel: err=%d\n", ret); return; } @@ -818,20 +835,31 @@ static int storvsc_execute_vstor_op(struct hv_device *device, { struct vstor_packet *vstor_packet; int ret, t; + u64 rqst_id; vstor_packet = &request->vstor_packet; init_completion(&request->wait_event); vstor_packet->flags = REQUEST_COMPLETION_FLAG; + rqst_id = vmbus_next_request_id(&device->channel->requestor, + (unsigned long)request); + if (rqst_id == VMBUS_RQST_ERROR) { + dev_err(&device->device, "No request id available\n"); + return -EAGAIN; + } + ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - vmscsi_size_delta), - (unsigned long)request, + rqst_id, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); - if (ret != 0) + if (ret != 0) { + /* Reclaim request ID to avoid leak of IDs */ + vmbus_request_addr(&device->channel->requestor, rqst_id); return ret; + } t = wait_for_completion_timeout(&request->wait_event, 5*HZ); if (t == 0) @@ -1233,9 +1261,17 @@ 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) { @@ -1256,6 +1292,12 @@ 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, @@ -1369,6 +1411,7 @@ static int storvsc_do_io(struct hv_device *device, int ret = 0; const struct cpumask *node_mask; int tgt_cpu; + u64 rqst_id; vstor_packet = &request->vstor_packet; stor_device = get_out_stor_device(device); @@ -1463,6 +1506,13 @@ static int storvsc_do_io(struct hv_device *device, vstor_packet->operation = VSTOR_OPERATION_EXECUTE_SRB; + rqst_id = vmbus_next_request_id(&outgoing_channel->requestor, + (unsigned long)request); + if (rqst_id == VMBUS_RQST_ERROR) { + dev_err(&device->device, "No request id available\n"); + return -EAGAIN; + } + if (request->payload->range.len) { ret = vmbus_sendpacket_mpb_desc(outgoing_channel, @@ -1470,18 +1520,21 @@ static int storvsc_do_io(struct hv_device *device, vstor_packet, (sizeof(struct vstor_packet) - vmscsi_size_delta), - (unsigned long)request); + rqst_id); } else { ret = vmbus_sendpacket(outgoing_channel, vstor_packet, (sizeof(struct vstor_packet) - vmscsi_size_delta), - (unsigned long)request, + rqst_id, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); } - if (ret != 0) + if (ret != 0) { + /* Reclaim request ID to avoid leak of IDs */ + vmbus_request_addr(&outgoing_channel->requestor, rqst_id); return ret; + } atomic_inc(&stor_device->num_outstanding_req); @@ -1562,7 +1615,7 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd) struct storvsc_cmd_request *request; struct vstor_packet *vstor_packet; int ret, t; - + u64 rqst_id; stor_device = get_out_stor_device(device); if (!stor_device) @@ -1577,14 +1630,24 @@ static int storvsc_host_reset_handler(struct scsi_cmnd *scmnd) vstor_packet->flags = REQUEST_COMPLETION_FLAG; vstor_packet->vm_srb.path_id = stor_device->path_id; + rqst_id = vmbus_next_request_id(&device->channel->requestor, + (unsigned long)&stor_device->reset_request); + if (rqst_id == VMBUS_RQST_ERROR) { + dev_err(&device->device, "No request id available\n"); + return FAILED; + } + ret = vmbus_sendpacket(device->channel, vstor_packet, (sizeof(struct vstor_packet) - vmscsi_size_delta), - (unsigned long)&stor_device->reset_request, + rqst_id, VM_PKT_DATA_INBAND, VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED); - if (ret != 0) + if (ret != 0) { + /* Reclaim request ID to avoid leak of IDs */ + vmbus_request_addr(&device->channel->requestor, rqst_id); return FAILED; + } t = wait_for_completion_timeout(&request->wait_event, 5*HZ); if (t == 0) -- 2.25.1
