[dpdk-dev] [PATCH 3/8] vhost: validate untrusted memory.nregions field

[Stefan Hajnoczi]

Check if memory.nregions is valid right away.  This eliminates the
possibility of bugs when memory.nregions is used later on in
vhost_user_set_mem_table().

Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
 lib/librte_vhost/vhost_user.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index a96afbe84..48b493d70 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -662,6 +662,12 @@ vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg)
 	uint32_t i;
 	int fd;
 
+	if (memory.nregions > VHOST_MEMORY_MAX_NREGIONS) {
+		RTE_LOG(ERR, VHOST_CONFIG,
+			"too many memory regions (%u)\n", memory.nregions);
+		return -1;
+	}
+
 	if (dev->mem && !vhost_memory_changed(&memory, dev->mem)) {
 		RTE_LOG(INFO, VHOST_CONFIG,
 			"(%d) memory regions not changed\n", dev->vid);
-- 
2.14.3