On 03/22/2018 02:41 AM, Fam Zheng wrote:
On Thu, 03/22 14:24, yuchen...@synology.com wrote:
From: yuchenlin <yuchen...@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 <yuchen...@synology.com>
---
+++ 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)
+
Hmm, with sectors instead of bytes, you don't want to use Phillipe's '2
* T_BYTE' macro after all; but it would still look better spelled as
'(1ULL << 32)' or '(4ULL * 1024 * 1024 * 1024)'. Most importantly,
since the value does NOT fit in a 32-bit unsigned integer, I think you
NEED to use the ULL suffix to make your intent clear.
#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
Cc'ing Kevin and Max who merge block/ patches.
Also, CC'ing qemu-block, as all block-related patches should go through
there.
Reviewed-by: Fam Zheng <f...@redhat.com>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org