Re: [PATCH] libceph: use 64-bit arithmetic instead of 32-bit
From: Ilya Dryomov <idryomov@gmail.com>
Date: 2018-01-31 09:39:18
Also in:
ceph-devel, lkml
On Wed, Jan 31, 2018 at 6:29 AM, Gustavo A. R. Silva [off-list ref] wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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 */
Hi Gustavo,
This (and other u32/u64 issues in this function, is this the only
warning?) is fixed in my striping v2 work branch. I wasn't going to
push that patch separately, but I guess I should post it.
Thanks,
Ilya