Messages in this thread | | | Date | Wed, 31 Jan 2018 06:02:53 -0600 | From | "Gustavo A. R. Silva" <> | Subject | Re: [PATCH] libceph: use 64-bit arithmetic instead of 32-bit |
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Hello Ilya,
Quoting Ilya Dryomov <idryomov@gmail.com>:
> On Wed, Jan 31, 2018 at 6:29 AM, Gustavo A. R. Silva > <gustavo@embeddedor.com> wrote: >> 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@embeddedor.com> >> --- >> 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. >
Yeah, this was the only one warning reported by Coverity in this particular module.
Thanks -- Gustavo
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