lkml.org 
[lkml]   [2018]   [Jan]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] libceph: use 64-bit arithmetic instead of 32-bit
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





\
 
 \ /
  Last update: 2018-01-31 13:26    [W:0.048 / U:0.112 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site