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:

quoted

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 <redacted>
---
 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