One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
struct boo entry[];
};
instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
security/integrity/ima/ima_template.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
index b631b8bc7624..b945dff2ed14 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -281,9 +281,8 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc,
int ret = 0;
int i;
- *entry = kzalloc(sizeof(**entry) +
- template_desc->num_fields * sizeof(struct ima_field_data),
- GFP_NOFS);
+ *entry = kzalloc(struct_size(*entry, template_data,
+ template_desc->num_fields), GFP_NOFS);
if (!*entry)
return -ENOMEM;
--
2.21.0
On Wed, 2019-08-28 at 13:29 -0500, Gustavo A. R. Silva wrote:
> Hi all,
>
> Friendly ping:
>
> Who can take this, please?
Thank you for the reminder. I'm just getting back from LSS and a very
short vacation. I'll look at it shortly.
Mimi
On 8/28/19 1:46 PM, Mimi Zohar wrote:
> On Wed, 2019-08-28 at 13:29 -0500, Gustavo A. R. Silva wrote:
>> Hi all,
>>
>> Friendly ping:
>>
>> Who can take this, please?
>
> Thank you for the reminder. I'm just getting back from LSS and a very
> short vacation. I'll look at it shortly.
>
Thanks, Mimi.
--
Gustavo
Hi all,
Friendly ping:
Who can take this, please?
Thanks
--
Gustavo
On 5/29/19 11:53 AM, Gustavo A. R. Silva wrote:
> One of the more common cases of allocation size calculations is finding
> the size of a structure that has a zero-sized array at the end, along
> with memory for some number of elements for that array. For example:
>
> struct foo {
> int stuff;
> struct boo entry[];
> };
>
> instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> security/integrity/ima/ima_template.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
> index b631b8bc7624..b945dff2ed14 100644
> --- a/security/integrity/ima/ima_template.c
> +++ b/security/integrity/ima/ima_template.c
> @@ -281,9 +281,8 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc,
> int ret = 0;
> int i;
>
> - *entry = kzalloc(sizeof(**entry) +
> - template_desc->num_fields * sizeof(struct ima_field_data),
> - GFP_NOFS);
> + *entry = kzalloc(struct_size(*entry, template_data,
> + template_desc->num_fields), GFP_NOFS);
> if (!*entry)
> return -ENOMEM;
>
>
Hi Gustavo,
On Wed, 2019-08-28 at 13:29 -0500, Gustavo A. R. Silva wrote:
> On 5/29/19 11:53 AM, Gustavo A. R. Silva wrote:
> > One of the more common cases of allocation size calculations is finding
> > the size of a structure that has a zero-sized array at the end, along
> > with memory for some number of elements for that array. For example:
> >
> > struct foo {
> > int stuff;
> > struct boo entry[];
> > };
> >
> > instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
> >
> > Instead of leaving these open-coded and prone to type mistakes, we can
> > now use the new struct_size() helper:
> >
> > instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);
> >
> > This code was detected with the help of Coccinelle.
> >
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
> > ---
> > security/integrity/ima/ima_template.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c
> > index b631b8bc7624..b945dff2ed14 100644
> > --- a/security/integrity/ima/ima_template.c
> > +++ b/security/integrity/ima/ima_template.c
> > @@ -281,9 +281,8 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc,
> > int ret = 0;
> > int i;
> >
> > - *entry = kzalloc(sizeof(**entry) +
> > - template_desc->num_fields * sizeof(struct ima_field_data),
> > - GFP_NOFS);
> > + *entry = kzalloc(struct_size(*entry, template_data,
> > + template_desc->num_fields), GFP_NOFS);
> > if (!*entry)
> > return -ENOMEM;
> >
> >
The same usage exists in ima_api.c: ima_alloc_init_template(). Did
you want to make the change there as well?
thanks,
Mimi
Hi Mimi,
On 8/28/19 10:45 PM, Mimi Zohar wrote:
>
> The same usage exists in ima_api.c: ima_alloc_init_template(). Did
> you want to make the change there as well?
>
Yep. I'll write a patch for that one too.
Thanks
--
Gustavo