[dpdk-dev] [PATCH 10/12] examples/vhost_scsi: move to safe GPA translation API

[Maxime Coquelin <maxime.coquelin@redhat.com>]

This patch uses the new rte_vhost_va_from_guest_pa() API
to ensure all the descriptor buffer is mapped contiguously
in the application virtual address space.

As the application did not checked return of previous API,
this patch just print an error if the buffer address isn't in
the vhost memory regions or if it is scattered. Ideally, it
should handle scattered buffers gracefully.

This issue has been assigned CVE-2018-1059.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
---
 examples/vhost_scsi/vhost_scsi.c | 56 +++++++++++++++++++++++++++++++++-------
 1 file changed, 47 insertions(+), 9 deletions(-)

diff --git a/examples/vhost_scsi/vhost_scsi.c b/examples/vhost_scsi/vhost_scsi.c
index 3cb4383e9..2908ff68b 100644
--- a/examples/vhost_scsi/vhost_scsi.c
+++ b/examples/vhost_scsi/vhost_scsi.c
@@ -38,7 +38,7 @@ vhost_scsi_ctrlr_find(__rte_unused const char *ctrlr_name)
 	return g_vhost_ctrlr;
 }
 
-static uint64_t gpa_to_vva(int vid, uint64_t gpa)
+static uint64_t gpa_to_vva(int vid, uint64_t gpa, uint64_t *len)
 {
 	char path[PATH_MAX];
 	struct vhost_scsi_ctrlr *ctrlr;
@@ -58,7 +58,7 @@ static uint64_t gpa_to_vva(int vid, uint64_t gpa)
 
 	assert(ctrlr->mem != NULL);
 
-	return rte_vhost_gpa_to_vva(ctrlr->mem, gpa);
+	return rte_vhost_va_from_guest_pa(ctrlr->mem, gpa, len);
 }
 
 static struct vring_desc *
@@ -108,15 +108,29 @@ static void
 vhost_process_read_payload_chain(struct vhost_scsi_task *task)
 {
 	void *data;
+	uint64_t chunck_len;
 
 	task->iovs_cnt = 0;
+	chunck_len = task->desc->len;
 	task->resp = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
-						   task->desc->addr);
+						   task->desc->addr,
+						   &chunck_len);
+	if (!task->resp || chunck_len != task->desc->len) {
+		fprintf(stderr, "failed to translate desc address.\n");
+		return;
+	}
 
 	while (descriptor_has_next(task->desc)) {
 		task->desc = descriptor_get_next(task->vq->desc, task->desc);
+		chunck_len = task->desc->len;
 		data = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
-						     task->desc->addr);
+						     task->desc->addr,
+							 &chunck_len);
+		if (!data || chunck_len != task->desc->len) {
+			fprintf(stderr, "failed to translate desc address.\n");
+			return;
+		}
+
 		task->iovs[task->iovs_cnt].iov_base = data;
 		task->iovs[task->iovs_cnt].iov_len = task->desc->len;
 		task->data_len += task->desc->len;
@@ -128,12 +142,20 @@ static void
 vhost_process_write_payload_chain(struct vhost_scsi_task *task)
 {
 	void *data;
+	uint64_t chunck_len;
 
 	task->iovs_cnt = 0;
 
 	do {
+		chunck_len = task->desc->len;
 		data = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
-						     task->desc->addr);
+						     task->desc->addr,
+							 &chunck_len);
+		if (!data || chunck_len != task->desc->len) {
+			fprintf(stderr, "failed to translate desc address.\n");
+			return;
+		}
+
 		task->iovs[task->iovs_cnt].iov_base = data;
 		task->iovs[task->iovs_cnt].iov_len = task->desc->len;
 		task->data_len += task->desc->len;
@@ -141,8 +163,12 @@ vhost_process_write_payload_chain(struct vhost_scsi_task *task)
 		task->desc = descriptor_get_next(task->vq->desc, task->desc);
 	} while (descriptor_has_next(task->desc));
 
+	chunck_len = task->desc->len;
 	task->resp = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
-						   task->desc->addr);
+						   task->desc->addr,
+						   &chunck_len);
+	if (!task->resp || chunck_len != task->desc->len)
+		fprintf(stderr, "failed to translate desc address.\n");
 }
 
 static struct vhost_block_dev *
@@ -188,6 +214,7 @@ process_requestq(struct vhost_scsi_ctrlr *ctrlr, uint32_t q_idx)
 		int req_idx;
 		uint16_t last_idx;
 		struct vhost_scsi_task *task;
+		uint64_t chunck_len;
 
 		last_idx = scsi_vq->last_used_idx & (vq->size - 1);
 		req_idx = vq->avail->ring[last_idx];
@@ -205,16 +232,27 @@ process_requestq(struct vhost_scsi_ctrlr *ctrlr, uint32_t q_idx)
 		assert((task->desc->flags & VRING_DESC_F_INDIRECT) == 0);
 		scsi_vq->last_used_idx++;
 
+		chunck_len = task->desc->len;
 		task->req = (void *)(uintptr_t)gpa_to_vva(task->bdev->vid,
-							  task->desc->addr);
+							  task->desc->addr,
+							  &chunck_len);
+		if (!task->req || chunck_len != task->desc->len) {
+			fprintf(stderr, "failed to translate desc address.\n");
+			return;
+		}
 
 		task->desc = descriptor_get_next(task->vq->desc, task->desc);
 		if (!descriptor_has_next(task->desc)) {
 			task->dxfer_dir = SCSI_DIR_NONE;
+			chunck_len = task->desc->len;
 			task->resp = (void *)(uintptr_t)
 					      gpa_to_vva(task->bdev->vid,
-							 task->desc->addr);
-
+							 task->desc->addr,
+							 &chunck_len);
+			if (!task->resp || chunck_len != task->desc->len) {
+				fprintf(stderr, "failed to translate desc address.\n");
+				return;
+			}
 		} else if (!descriptor_is_wr(task->desc)) {
 			task->dxfer_dir = SCSI_DIR_TO_DEV;
 			vhost_process_write_payload_chain(task);
-- 
2.14.3