Re: [PATCH] libceph: use 64-bit arithmetic instead of 32-bit
Hello Ilya,
Quoting Ilya Dryomov :
On Wed, Jan 31, 2018 at 6:29 AM, Gustavo A. R. Silva
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
---
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
Re: [PATCH] libceph: use 64-bit arithmetic instead of 32-bit
On Wed, Jan 31, 2018 at 6:29 AM, Gustavo A. R. Silva
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
> ---
> 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
[PATCH] libceph: use 64-bit arithmetic instead of 32-bit
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
---
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
