[PATCH] libceph: use 64-bit arithmetic instead of 32-bit

[Gustavo A. R. Silva]

Cast objsetno to u64 in order to give the compiler complete
information about the proper arithmetic to use. Notice
that this variable is used in a context that expects an
expression of type u64 (64 bits, unsigned).

The expression objsetno * sc + stripepos is currently
being evaluated using 32-bit arithmetic.

In general, the use of incorrect arithmetic has security
implications.

Addresses-Coverity-ID: 200686
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
---
 net/ceph/osdmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 0da27c6..58dc965 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -2183,7 +2183,7 @@ int ceph_calc_file_object_mapping(struct ceph_file_layout *layout,
 	stripepos = bl % sc;
 	objsetno = stripeno / su_per_object;
 
-	*ono = objsetno * sc + stripepos;
+	*ono = (u64)objsetno * sc + stripepos;
 	dout("objset %u * sc %u = ono %u\n", objsetno, sc, (unsigned int)*ono);
 
 	/* *oxoff = *off % layout->fl_stripe_unit;  # offset in su */
-- 
2.7.4