[Qemu-block] [PATCH 2/2] block/vhdx: check for offset overflow to bdrv_truncate()

[Jeff Cody]

VHDX uses uint64_t types for most offsets, following the VHDX spec.
However, bdrv_truncate() takes an int64_t value for the truncating
offset.  Check for overflow before calling bdrv_truncate().

N.B.: For a compliant image this is not an issue, as the maximum VHDX
image size is defined per the spec to be 64TB.

Signed-off-by: Jeff Cody <address@hidden>
---
 block/vhdx-log.c | 4 ++++
 block/vhdx.c     | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/block/vhdx-log.c b/block/vhdx-log.c
index fd4e7af..3b74e5d 100644
--- a/block/vhdx-log.c
+++ b/block/vhdx-log.c
@@ -554,6 +554,10 @@ static int vhdx_log_flush(BlockDriverState *bs, 
BDRVVHDXState *s,
             if (new_file_size % (1024*1024)) {
                 /* round up to nearest 1MB boundary */
                 new_file_size = ((new_file_size >> 20) + 1) << 20;
+                if (new_file_size > INT64_MAX) {
+                    ret = -EINVAL;
+                    goto exit;
+                }
                 bdrv_truncate(bs->file, new_file_size, PREALLOC_MODE_OFF, 
NULL);
             }
         }
diff --git a/block/vhdx.c b/block/vhdx.c
index 6a14999..c45af73 100644
--- a/block/vhdx.c
+++ b/block/vhdx.c
@@ -1177,6 +1177,9 @@ static int vhdx_allocate_block(BlockDriverState *bs, 
BDRVVHDXState *s,
 
     /* per the spec, the address for a block is in units of 1MB */
     *new_offset = ROUND_UP(*new_offset, 1024 * 1024);
+    if (*new_offset > INT64_MAX) {
+        return -EINVAL;
+    }
 
     return bdrv_truncate(bs->file, *new_offset + s->block_size,
                          PREALLOC_MODE_OFF, NULL);
-- 
2.9.4