migration: fix potential overflow in multifd send

I would guess it won't happen normally, but this should ease Coverity.

>>>     CID 1394385:  Integer handling issues  (OVERFLOW_BEFORE_WIDEN)
>>>     Potentially overflowing expression "pages->used * 8192U" with type "unsigned int" (32 bits, unsigned) is evaluated using 32-bit arithmetic, and then used in a context that expects an expression of type "uint64_t" (64 bits, unsigned).
854         transferred = pages->used * TARGET_PAGE_SIZE + p->packet_len;

Fixes: CID 1394385
CC: Juan Quintela <quintela@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180720034713.11711-1-peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index 52dd678092ee66ddbf27785b647f5498fa98f072..fdd108475c60c30e5e786975949a2282ac98527c 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -851,7 +851,7 @@ static void multifd_send_pages(void)
     p->pages->block = NULL;
     multifd_send_state->pages = p->pages;
     p->pages = pages;
-    transferred = pages->used * TARGET_PAGE_SIZE + p->packet_len;
+    transferred = ((uint64_t) pages->used) * TARGET_PAGE_SIZE + p->packet_len;
     ram_counters.multifd_bytes += transferred;
     ram_counters.transferred += transferred;;
     qemu_mutex_unlock(&p->mutex);