[dpdk-dev] [PATCH 8/8] vhost: check for memory_size + mmap_offset overflow

[Stefan Hajnoczi]

If memory_size + mmap_offset overflows then the memory region is bogus.
Do not use the overflowed mmap_size value for mmap().

Signed-off-by: Stefan Hajnoczi <stefanha at redhat.com>
---
 lib/librte_vhost/vhost_user.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
index 7d282cb36..cf742a558 100644
--- a/lib/librte_vhost/vhost_user.c
+++ b/lib/librte_vhost/vhost_user.c
@@ -729,7 +729,17 @@ vhost_user_set_mem_table(struct virtio_net *dev, struct VhostUserMsg *pmsg)
 		reg->fd              = fd;
 
 		mmap_offset = memory.regions[i].mmap_offset;
-		mmap_size   = reg->size + mmap_offset;
+
+		/* Check for memory_size + mmap_offset overflow */
+		if (mmap_offset >= -reg->size) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"mmap_offset (%#"PRIx64") and memory_size "
+				"(%#"PRIx64") overflow\n",
+				mmap_offset, reg->size);
+			goto err_mmap;
+		}
+
+		mmap_size = reg->size + mmap_offset;
 
 		/* mmap() without flag of MAP_ANONYMOUS, should be called
 		 * with length argument aligned with hugepagesz at older
-- 
2.14.3