block: fix theoretical overflow in bdrv_init_padding()

Calculation of sum may theoretically overflow, so use 64bit type and
add some good assertions.

Use int64_t constantly.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: tweak assertion order]
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-12-11 21:39:21 +03:00 committed by Eric Blake
parent 4c002cef0e
commit a56ed80c42
1 changed files with 6 additions and 2 deletions

View File

@ -1565,8 +1565,12 @@ static bool bdrv_init_padding(BlockDriverState *bs,
int64_t offset, int64_t bytes,
BdrvRequestPadding *pad)
{
uint64_t align = bs->bl.request_alignment;
size_t sum;
int64_t align = bs->bl.request_alignment;
int64_t sum;
bdrv_check_request(offset, bytes, &error_abort);
assert(align <= INT_MAX); /* documented in block/block_int.h */
assert(align <= SIZE_MAX / 2); /* so we can allocate the buffer */
memset(pad, 0, sizeof(*pad));