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From fa5b57175364431245b006c2afcbf94dc2b15400 Mon Sep 17 00:00:00 2001
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Wed, 29 May 2019 11:53:43 -0500
Subject: [PATCH] ima: use struct_size() in kzalloc()

References: jsc#SLE-15857 jsc#SLE-13618 bsc#1176918 ltc#186474
Patch-mainline: v5.4-rc1
Git-commit: fa5b57175364431245b006c2afcbf94dc2b15400

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 <gustavo@embeddedor.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 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 f5b950e0a955..6aa6408603e3 100644
--- a/security/integrity/ima/ima_template.c
+++ b/security/integrity/ima/ima_template.c
@@ -306,9 +306,8 @@ 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;
 
-- 
2.28.0