[Qemu-devel] [PATCH v2] vmdk: return ERROR when cluster sector is larger than vmdk limitation

[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 avoid writing the user data beyond limitation and record a useless offset
in grain table. We should return ERROR here.

Signed-off-by: yuchenlin <yuchenlin@synology.com>
---
v1->v2:
 - change commit message
 - check before allocating
 - should be >=
 - the unit is sector now

 thanks

 block/vmdk.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/vmdk.c b/block/vmdk.c
index f94c49a9c0..a1c21dbbba 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -47,6 +47,8 @@
 #define VMDK4_FLAG_MARKER (1 << 17)
 #define VMDK4_GD_AT_END 0xffffffffffffffffULL
 
+#define VMDK_EXTENT_MAX_SECTORS (4294967296)
+
 #define VMDK_GTE_ZEROED 0x1
 
 /* VMDK internal error codes */
@@ -1250,6 +1252,10 @@ static int get_cluster_offset(BlockDriverState *bs,
             return zeroed ? VMDK_ZEROED : VMDK_UNALLOC;
         }
 
+        if (extent->next_cluster_sector >= VMDK_EXTENT_MAX_SECTORS) {
+            return VMDK_ERROR;
+        }
+
         cluster_sector = extent->next_cluster_sector;
         extent->next_cluster_sector += extent->cluster_sectors;
 
-- 
2.16.2