[Qemu-devel] [PATCH] vmdk: return ENOTSUP before offset overflow

[yuchenlin@synology.com]

From: yuchenlin <yuchenlin@synology.com>

VMDK has a hard limitation of extent size, which is due to the size of grain
table entry is 32 bits. It means it can only point to a grain located at
offset = 2^32. To prevent offset overflow and record a useless offset
in grain table. We should return un-support here.

Signed-off-by: yuchenlin <yuchenlin@synology.com>
---
 block/vmdk.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c
index f94c49a9c0..d8fc961940 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -47,6 +47,9 @@
 #define VMDK4_FLAG_MARKER (1 << 17)
 #define VMDK4_GD_AT_END 0xffffffffffffffffULL
 
+/* 2TB */
+#define VMDK_EXTENT_SIZE_LIMIT (2199023255552)
+
 #define VMDK_GTE_ZEROED 0x1
 
 /* VMDK internal error codes */
@@ -1645,6 +1648,9 @@ static int vmdk_pwritev(BlockDriverState *bs, uint64_t offset,
                 return ret;
             }
             if (m_data.valid) {
+                if (cluster_offset > VMDK_EXTENT_SIZE_LIMIT) {
+                    return -ENOTSUP;
+                }
                 /* update L2 tables */
                 if (vmdk_L2update(extent, &m_data,
                                   cluster_offset >> BDRV_SECTOR_BITS)
-- 
2.16.2